Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

As of ~~April 29,~~July 28, 2021, there were ~~75,092,567~~75,497,259 shares of Common Stock, $0.0001 par value per share, outstanding.


	March 31, 2021			December 31, 2020			June 30, 2021			December 31, 2020
Assets
Current assets:
Cash and cash equivalents	$	88,471		$	85,918		$	141,309		$	85,918
Short-term investments		135,894			163,322			94,581			163,322
Accounts receivable		17,843			12,881			17,887			12,881
Inventory		3,114			2,644			3,905			2,644
Prepaid expenses and other current assets		9,374			9,285			15,058			9,285
Restricted cash		815			2,481			762			2,481
Total current assets		255,511			276,531			273,502			276,531
Property and equipment, net		1,984			2,219			1,755			2,219
Operating lease right-of-use assets		9,020			9,363			8,665			9,363
Long-term investments		7,676			24,215			2,006			24,215
Restricted cash		718			722			639			722
Total assets	$	274,909		$	313,050		$	286,567		$	313,050
Liabilities and stockholders’ (deficit) equity
Current liabilities:
Accounts payable	$	3,040		$	4,450		$	2,309		$	4,450
Accrued expenses		55,611			52,930			53,211			52,930
Deferred revenue		0			297			0			297
Operating lease liabilities		1,997			1,917			2,079			1,917
Other current liabilities		1,360			609			524			609
Total current liabilities		62,008			60,203			58,123			60,203
Convertible senior notes		168,704			117,928			168,899			117,928
Deferred royalty obligation		73,088			73,088			132,478			73,088
Operating lease liabilities, net of current portion		10,749			11,285			10,199			11,285
Total liabilities		314,549			262,504			369,699			262,504
Stockholders’ (deficit) equity:
Preferred stock, $0.0001 par value; 5,000 shares authorized; NaN issued and outstanding		—			—
Common stock, $0.0001 par value; 200,000 shares authorized; 75,062 and 73,923 shares issued and outstanding at March 31, 2021 and December 31, 2020, respectively		8			7
Preferred stock, $0.0001 par value; 5,000 shares authorized; NaN issued and outstanding								—			—
Common stock, $0.0001 par value; 200,000 shares authorized; 75,334 and 73,923 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively								8			7
Additional paid-in capital		1,072,025			1,119,632			1,082,220			1,119,632
Accumulated other comprehensive income		301			518			196			518
Accumulated deficit		(1,111,974	)		(1,069,611	)		(1,165,556	)		(1,069,611	)
Total stockholders’ (deficit) equity		(39,640	)		50,546			(83,132	)		50,546
Total liabilities and stockholders’ equity	$	274,909		$	313,050
Total liabilities and stockholders’ (deficit) equity							$	286,567		$	313,050


	Three Months Ended March 31,						Three Months Ended June 30,						Six Months Ended June 30,
	2021			2020			2021			2020			2021			2020
Revenues:
Product revenue, net	$	21,731		$	16,061		$	20,179		$	18,601		$	41,910		$	34,662
License and other revenue		1,529			2,077			2,422			14,913			3,951			16,990
Total revenues		23,260			18,138			22,601			33,514			45,861			51,652
Operating expenses:
Cost of sales		933			819			1,138			396			2,071			1,215
Research and development		37,050			33,997			33,981			42,594			71,031			76,591
Selling, general and administrative		37,650			30,678			36,530			30,843			74,180			61,521
Total operating expenses		75,633			65,494			71,649			73,833			147,282			139,327
Loss from operations		(52,373	)		(47,356	)		(49,048	)		(40,319	)		(101,421	)		(87,675	)
Other income (expense):
Interest income		264			975			165			849			429			1,824
Interest expense		(5,095	)		(6,509	)		(5,001	)		(6,758	)		(10,096	)		(13,267	)
Other (expense) income, net		(61	)		25
Other income (expense), net								436			(61	)		375			(36	)
Total other expense, net		(4,892	)		(5,509	)		(4,400	)		(5,970	)		(9,292	)		(11,479	)
Loss before income taxes		(57,265	)		(52,865	)		(53,448	)		(46,289	)		(110,713	)		(99,154	)
Income tax provision		(149	)		(66	)		(134	)		(137	)		(283	)		(203	)
Net loss	$	(57,414	)	$	(52,931	)	$	(53,582	)	$	(46,426	)	$	(110,996	)	$	(99,357	)
Net loss per share—basic and diluted	$	(0.77	)	$	(0.78	)	$	(0.71	)	$	(0.63	)	$	(1.48	)	$	(1.41	)
Weighted-average number of common shares outstanding used in net loss per share—basic and diluted		74,517			67,627			75,189			73,237			74,863			70,475


	Three Months Ended March 31,						Six Months Ended June 30,
	2021			2020			2021			2020
Operating activities
Net loss	$	(57,414	)	$	(52,931	)	$	(110,996	)	$	(99,357	)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		235			242			464			480
Net amortization of premiums and discounts on investments		664			12			1,148			89
Amortization of debt discount and issuance costs		191			1,912			386			3,919
Stock-based compensation expense		7,359			5,152			15,494			11,580
Realized and unrealized gains on marketable equity securities		(14	)		0			(14	)		0
Inventory obsolescence charge		82			0			245			0
Change in fair value of embedded derivative liability								(610	)		0
Changes in operating assets and liabilities:
Accounts receivable		(4,962	)		(1,419	)		(5,006	)		(1,719	)
Inventory		(552	)		(624	)		(1,506	)		(1,306	)
Prepaid expenses and other current assets		(89	)		(268	)		(5,773	)		(682	)
Operating lease right-of-use assets		343			297			698			605
Accounts payable		(1,410	)		711		��	(2,141	)		903
Accrued expenses and other liabilities		3,432			3,350			196			5,228
Deferred revenue		(297	)		(1,054	)		(297	)		(4,236	)
Operating lease liabilities		(456	)		(391	)		(924	)		(792	)
Net cash used in operating activities		(52,888	)		(45,011	)		(108,636	)		(85,288	)
Investing activities
Purchases of property and equipment		0			(10	)		0			(26	)
Proceeds from maturities of investments		68,950			47,413
Proceeds from sales and maturities of investments								124,376			99,286
Purchases of investments		(25,764	)		(93,882	)		(34,732	)		(205,773	)
Net cash provided by (used in) investing activities		43,186			(46,479	)		89,644			(106,513	)
Financing activities
Proceeds from issuance of common stock, net of issuance costs		9,903			162,096			9,903			161,803
Proceeds from the exercise of stock options and shares issued under employee stock purchase plan		773			2,733			2,833			5,072
Proceeds from Amended Revenue Interest Agreement								60,000			0
Net cash provided by financing activities		10,676			164,829			72,736			166,875
Effect of exchange rate on cash, cash equivalents and restricted cash		(91	)		(80	)		(155	)		(32	)
Net increase in cash, cash equivalents and restricted cash		883			73,259
Net increase (decrease) in cash, cash equivalents and restricted cash								53,589			(24,958	)
Cash, cash equivalents and restricted cash at beginning of period		89,121			130,689			89,121			130,689
Cash, cash equivalents and restricted cash at end of period	$	90,004		$	203,948		$	142,710		$	105,731
Reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets
Cash and cash equivalents	$	88,471		$	202,247		$	141,309		$	103,102
Short-term restricted cash		815			987			762			1,915
Long-term restricted cash		718			714			639			714
Total cash, cash equivalents and restricted cash	$	90,004		$	203,948		$	142,710		$	105,731
Supplemental disclosures:
Deferred financing costs in accrued expenses	$	0		$	294
Cash paid for interest on convertible debt							$	2,588		$	2,588
Cash paid for amounts included in the measurement of operating lease liabilities	$	815		$	796		$	1,630		$	1,592
Cash paid for interest on deferred royalty obligation	$	2,457		$	1,240		$	4,068		$	2,400


	Common Shares																Common Shares				Additional Paid-In Capital			Accumulated Other Comprehensive Income (Loss)			Accumulated Deficit			Total Stockholders’ (Deficit) Equity
																	Shares		Amount
Balance at March 31, 2021																		75,062	$	8	$	1,072,025		$	301		$	(1,111,974	)	$	(39,640	)
Vesting of restricted stock																		2		—		—			—			—			—
Exercise of stock options and shares issued under the employee stock purchase plan																		270		0		2,060			0			0			2,060
Stock-based compensation expense																		—		0		8,135			0			0			8,135
Unrealized loss on investments																		—		0		0			(41	)		0			(41	)
Foreign currency cumulative translation adjustment																		—		0		0			(64	)		0			(64	)
Net loss																		—		0		0			0			(53,582	)		(53,582	)
Balance at June 30, 2021																		75,334	$	8	$	1,082,220		$	196		$	(1,165,556	)	$	(83,132	)

Balance at March 31, 2020																		73,095		7		1,092,829			(420	)		(926,269	)		166,147
Exercise of stock options and shares issued under the employee stock purchase plan																		271		0		2,339			0			0			2,339
Stock-based compensation expense																		—		0		6,428			0			0			6,428
Unrealized gain on investments																		—		0		0			1,273			0			1,273
Foreign currency translation adjustment																		—		0		0			38			0			38
Net loss																		—		0		0			0			(46,426	)		(46,426	)
Balance at June 30, 2020																		73,366	$	7	$	1,101,596		$	891		$	(972,695	)	$	129,799
	Shares		Amount		Additional Paid-In Capital			Accumulated Other Comprehensive Income (Loss)			Accumulated Deficit			Total Stockholders’ (Deficit) Equity
Balance at December 31, 2020		73,923	$	7	$	1,119,632		$	518		$	(1,069,611	)	$	50,546			73,923	$	7	$	1,119,632		$	518		$	(1,069,611	)	$	50,546
Vesting of restricted stock		409		—		—			—			—			—			411		0		0			0			0			0
Exercise of stock options and shares issued under the employee stock purchase plan		92		0		773			0			0			773			362		0		2,833			0			0			2,833
Stock-based compensation expense		0		0		7,359			0			0			7,359			—		0		15,494			0			0			15,494
Issuance of common stock, net of issuance costs		638		1		9,902			0			0			9,903			638		1		9,902			0			0			9,903
Cumulative effect adjustment for adoption of new accounting guidance		0		0		(65,641	)		0			15,051			(50,590	)		—		0		(65,641	)		0			15,051			(50,590	)
Unrealized loss on investments		0		0		0			(132	)		0			(132	)		—		0		0			(173	)		0			(173	)
Foreign currency cumulative translation adjustment		0		0		0			(85	)		0			(85	)		—		0		0			(149	)		0			(149	)
Net loss		0		0		0			0			(57,414	)		(57,414	)		—		0		0			0			(110,996	)	$	(110,996	)
Balance at March 31, 2021		75,062	$	8	$	1,072,025		$	301		$	(1,111,974	)	$	(39,640	)
Balance at June 30, 2021																		75,334	$	8	$	1,082,220		$	196		$	(1,165,556	)	$	(83,132	)

Balance at December 31, 2019		65,370	$	7	$	923,142		$	(37	)	$	(873,338	)	$	49,774			65,370	$	7	$	923,142		$	(37	)	$	(873,338	)	$	49,774
Vesting of restricted stock		189		—		—			—			—			—			189		0		0			0			0			0
Exercise of stock options and shares issued under the employee stock purchase plan		348		0		2,733			0			0			2,733			619		0		5,072			0			0			5,072
Issuance of common stock, net of issuance costs																		7,188		0		161,802			0			0			161,802
Stock-based compensation expense		0		0		5,152			0			0			5,152			—		0		11,580			0			0			11,580
Issuance of common stock, net of issuance costs		7,188		0		161,802			0			0			161,802
Unrealized loss on investments		0		0		0			(314	)		0			(314	)
Foreign currency cumulative translation adjustment		0		0		0			(69	)		0			(69	)
Unrealized gain on investments																		—		0		0			959			0			959
Foreign currency translation adjustment																		—		0		0			(31	)		0			(31	)
Net loss		0		0		0			0			(52,931	)		(52,931	)		—		0		0			0			(99,357	)		(99,357	)
Balance at March 31, 2020		73,095	$	7	$	1,092,829		$	(420	)	$	(926,269	)	$	166,147

Balance at June 30, 2020																		73,366	$	7	$	1,101,596		$	891		$	(972,695	)	$	129,799

Measures not related to income-based taxes within the CARES Act include (1) allowing an employer to pay its share of Social Security payroll taxes that would otherwise be due from the date of enactment through December 31, 2020 over the following two years and (2) allowing eligible employers subject to closure due to the COVID-19 pandemic to receive a 50% credit on qualified wages against their employment taxes each quarter, with any excess credits eligible for refunds. These measures of the CARES Act also are not material to our condensed consolidated financial statements or related disclosures.

6. Fair Value of Financial Instruments

Financial instruments, including cash, restricted cash, prepaid expenses and other current assets, accounts payable and accrued expenses, are presented at amounts that approximate fair value at ~~March 31,~~June 30, 2021 and December 31, 2020.

We are required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs:

Level 1 inputs - Quoted prices in active markets for identical assets or liabilities

Level 2 inputs - Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly

Level 3 inputs - Unobservable inputs that reflect our own assumptions about the assumptions market participants would use in pricing the asset or liability

Our cash equivalents are comprised of money market funds, U.S. government and agency securities, commercial paper and corporate debt securities as presented in the tables below. We measure these investments at fair value. The fair value of cash equivalents is determined based on “Level 1” or ~~"Level 2"~~“Level 2” inputs.

Items classified as Level 2 within the valuation hierarchy consist of corporate debt securities, commercial paper ~~certificates of deposit~~ and U.S. government and agency securities. We estimate the fair values of these marketable securities by taking into consideration valuations obtained from third-party pricing sources. These pricing sources utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include market pricing based on real-time trade data for the same or similar securities, issuer credit spreads, benchmark yields, and other observable inputs. We validate the prices provided by our third-party pricing sources by understanding the models used, obtaining market values from other pricing sources and analyzing pricing data in certain instances.

In certain cases where there is limited activity or less transparency around inputs to valuation, the related assets or liabilities are classified as Level 3. The embedded derivative liability associated with our deferred royalty obligation, as discussed further in Note 11, “Long-Term Obligations”, is measured at fair value using an option pricing Monte Carlo simulation model and is included as a component of the deferred royalty obligation. The embedded derivative liability is subject to remeasurement at the end of each reporting period, with changes in fair value recognized as a component of other income (expense), net. The assumptions used in the

1110

Table of Contents

option pricing Monte Carlo simulation model include: (1) our estimates of the probability and timing of related events; (2) the probability-weighted net sales of XPOVIO and any of our other future products, including worldwide net product sales, upfront payments, milestones and royalties; (3) our risk-adjusted discount rate that includes a company specific risk premium; (4) our cost of debt; (5) volatility; and (6) the probability of a change in control occurring during the term of the instrument. Our embedded derivative liability, as well as the estimated fair value of the deferred royalty obligation, is described in Note 2, “Summary of Significant Accounting Policies,” and Note 15, “Long-Term Obligations” to our consolidated financial statements contained in Item 8 of our Annual Report.

The following table presents information about our financial assets and liability that have been measured at fair value at ~~March 31,~~June 30, 2021 and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands):


Description	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Financial assets
Cash equivalents:
Money market funds	$	21,954	$	21,954	$	—	$	—	$	97,268	$	97,268	$	—	$	—
Commercial paper		10,749		—		10,749		—		1,000		1,000		—		—
Corporate debt securities		3,000		—		3,000		—
Investments:
Short-term:
Corporate debt securities		114,948		—		114,948		—		77,691		—		77,691		—
Commercial paper		18,987		—		18,987		—		15,991		—		15,991		—
Certificate of deposit		1,056		—		1,056		—
U.S. government and agency securities		903		—		903		—		899		—		899		—
Long-term:
Corporate debt securities (one to two-year maturity)		7,676		—		7,676		—		2,006		—		2,006		—
	$	179,273	$	21,954	$	157,319	$	—	$	194,855	$	98,268	$	96,587	$	—
Financial liability
Embedded derivative liability	$	1,800			$	—	$	1,800	$	2,140			$	—	$	2,140

The following table presents information about our financial assets and liability that have been measured at fair value at December 31, 2020 and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands):


Description	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Financial assets
Cash equivalents:
Money market funds	$	3,586	$	3,586	$	—	$	—
U.S. government and agency securities		16,000		16,000		—		—
Commercial paper		8,999		—		8,999		—
Corporate debt securities		2,755		—		2,755		—
Investments:
Short-term:
Corporate debt securities		136,833		—		136,833		—
Commercial paper		23,487		—		23,487		—
U.S. government and agency securities		3,002		—		3,002		—
Long-term:
Corporate debt securities (one to two-year maturity)		23,309		—		23,309		—
U.S. government and agency securities (one to two-year maturity)		906		—		906		—
	$	218,877	$	19,586	$	199,291	$	—
Financial liability
Embedded derivative liability	$	1,800			$	—	$	1,800

Table of Contents

Description

Total

Quoted
Prices
in Active
Markets for Identical Assets
(Level 1)

Significant
Other
Observable
Inputs
(Level 2)

Significant
Unobservable
Inputs
(Level 3)

Financial assets

Cash equivalents:

Money market funds

$
3,586

$
3,586

$
—

$
—

U.S. government and agency securities

16,000

16,000

—

—

Commercial paper

8,999

—

8,999

—

Corporate debt securities

2,755

—

2,755

—

Investments:

Short-term:

Corporate debt securities

136,833

—

136,833

—

Commercial paper

23,487

—

23,487

—

U.S. government and agency securities

3,002

—

3,002

—

Long-term:

Corporate debt securities (one to two-year maturity)

23,309

—

23,309

—

U.S. government and agency securities (one
to two-year maturity)

906

—

906

—

$
218,877

$
19,586

$
199,291

$
—

Financial liability

Embedded derivative liability

$
1,800

$
—

$
1,800

The following table sets forth a summary of the changes in the estimated fair value of our embedded derivative liability during the six months ended June 30, 2021 (in thousands):


	Embedded Derivative Liability
Balance as of December 31, 2020	$	1,800
Change in fair value since issuance		(610	)
Addition of value as a result of Amended Revenue Interest Agreement		950
Balance as of June 30, 2021	$	2,140

7. Investments

The following table summarizes our investments in debt securities, classified as available-for-sale, as of ~~March 31,~~June 30, 2021 (in thousands):


	Amortized Cost		Total Unrealized Gains		Total Unrealized Loss			Aggregate Fair Value		Amortized Cost		Total Unrealized Gains		Total Unrealized Loss			Aggregate Fair Value
Short-term:
Corporate debt securities	$	114,809	$	173	$	(34	)	$	114,948	$	77,586	$	111	$	(6	)	$	77,691
Commercial paper		18,987		3		(3	)		18,987		15,993		1		(3	)		15,991
Certificate of deposit		1,056		0		0			1,056
U.S. government and agency securities		895		8		0			903		894		5		0			899
Long-term:
Corporate debt securities (one to two-year maturity)		7,672		9		(5	)		7,676		2,006		0		0			2,006
	$	143,419	$	193	$	(42	)	$	143,570	$	96,479	$	117	$	(9	)	$	96,587

The following table summarizes our investments in debt securities, classified as available-for-sale, as of December 31, 2020 (in thousands):


	Amortized Cost		Total Unrealized Gains		Total Unrealized Loss			Aggregate Fair Value
Short-term:
Corporate debt securities	$	136,677	$	189	$	(33	)	$	136,833
Commercial paper		23,485		3		(1	)		23,487
U.S. government and agency securities		3,002		0		0			3,002
Long-term:
Corporate debt securities (one to two-year maturity)		23,195		126		(12	)		23,309
U.S. government and agency securities (one to two-year maturity)		897		9		0			906
	$	187,256	$	327	$	(46	)	$	187,537

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We determine the appropriate classification of our investments in debt securities at the time of purchase. All of our securities are classified as available-for-sale and are reported as short-term investments or long-term investments based on maturity dates and whether such assets are reasonably expected to be realized in cash or sold or consumed during the normal cycle of business. Available-for-sale investments are recorded at fair value. Short-term and long-term investments are composed of corporate debt securities, commercial paper, certificate of deposit and U.S. government and agency securities. We review investments whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. We evaluate whether the decline in fair value has resulted from credit losses or other factors. In making this assessment, we consider the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security, among other factors. If this assessment indicates that a credit loss exists, the present value of cash flows expected to be collected from the security is compared to the amortized cost basis of the security. If the present value of cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded on our condensed consolidated balance sheet, limited by the amount that the fair value is less than the amortized cost basis. Any impairment that is 0t0t related to a credit loss is recognized in other comprehensive income.

Changes in the allowance for credit losses are recorded as a provision for (or reversal of) credit loss expense. Losses are charged against the allowance when we believe the uncollectability of an available-for-sale security is confirmed or when either of the criteria regarding intent or requirement to sell is met. The unrealized losses at ~~March 31,~~June 30, 2021 and December 31, 2020 were attributable to changes in interest rates, and we do not believe any unrealized losses represent credit losses.

We held 3420 and 37 commercial paper and corporate debt securities at ~~March 31,~~June 30, 2021 and December 31, 2020, respectively, that were in an unrealized loss position. We do not intend to sell the investments before recovery of their amortized cost bases, which may be maturity. The following table summarizes these available-for-sale securities in an unrealized loss position for which an allowance for credit losses has not been recorded at ~~March 31,~~June 30, 2021, aggregated by major security type and length of time in a continuous unrealized loss position (in thousands):


	Less than 12 Months					12 Months or Longer				Total					Less than 12 Months					12 Months or Longer				Total
	Aggregate Related Fair Value		Unrealized Losses			Aggregate Related Fair Value		Unrealized Losses		Aggregate Related Fair Value		Unrealized Losses			Aggregate Related Fair Value		Unrealized Losses			Aggregate Related Fair Value		Unrealized Losses		Aggregate Related Fair Value		Unrealized Losses
Corporate debt securities	$	76,266	$	(39	)	$	—	$	—	$	76,266	$	(39	)	$	34,300	$	(6	)	$	—	$	—	$	34,300	$	(6	)
Commercial paper		9,989		(3	)		—		—		9,989		(3	)		9,993		(3	)		—		—		9,993		(3	)
Total	$	86,255	$	(42	)	$	—	$	—	$	86,255	$	(42	)	$	44,293	$	(9	)	$	—	$	—	$	44,293	$	(9	)

The following table summarizes our debt securities in an unrealized loss position for which an allowance for credit losses has not been recorded at December 31, 2020, aggregated by major security type and length of time in a continuous unrealized loss position (in thousands):


	Less than 12 Months					12 Months or Longer				Total
	Aggregate Related Fair Value		Unrealized Losses			Aggregate Related Fair Value		Unrealized Losses		Aggregate Related Fair Value		Unrealized Losses
Corporate debt securities	$	85,984	$	(45	)	$	—	$	—	$	85,984	$	(45	)
Commercial paper		2,496		(1	)		—		—		2,496		(1	)
Total	$	88,480	$	(46	)	$	—	$	—	$	88,480	$	(46	)

11. Long-Term Obligations

3.00% Convertible Senior Notes due 2025

On October 16, 2018, we completed an offering of ~~$150.0~~$150.0 million aggregate principal amount of the Notes. In addition, on October 26, 2018, we issued an additional ~~$22.5~~$22.5 million aggregate principal amount of the Notes pursuant to the full exercise of the option to purchase additional Notes granted to the initial purchasers in the offering. The Notes were sold in a private offering to qualified institutional buyers in reliance on Rule 144A under the Securities Act. In accordance with accounting guidance in effect at the time of the offering, for debt with conversion and other options, we separately accounted for the liability component (“Liability Component”) and the embedded conversion option (“Equity Component”) of the Notes by allocating the proceeds between the Liability Component and the Equity Component, due to our ability to settle the Notes in cash, shares of our common stock or a combination of cash and shares of our common stock, at our option. In connection with the issuance of the Notes, we incurred approximately ~~$5.6~~$5.6 million of debt issuance costs, which primarily consisted of underwriting, legal and other professional fees, and allocated these costs between the Liability Component and the Equity Component based on the allocation of the proceeds. Of the total debt issuance costs, ~~$2.2~~$2.2 million was allocated to the Equity Component and recorded as a reduction to additional paid-in capital and ~~$3.4~~$3.4 million was allocated to the Liability Component and recorded as a reduction of the Notes. The portion allocated to the Liability Component is amortized to interest expense using the effective interest method over seven years.

In 2021, upon adoption of ASU 2020-06, we reclassified the Equity Component as of January 1, 2021 and combined it with the Liability Component of the Notes, increasing the carrying value of our convertible debt by approximately ~~$50.6~~$50.6 million, with a corresponding decrease to additional paid-in capital of ~~$65.6~~$65.6 million and accumulated deficit of ~~$15.0~~$15.0 million. Our deferred tax liability related to the Notes also decreased by approximately ~~$11.8~~$11.8 million, with a corresponding increase in the income tax valuation allowance.

The Notes are senior unsecured obligations and bear interest at a rate of ~~3.00%~~3.00% per year payable semiannually in arrears on April 15 and October 15 of each year, beginning on April 15, 2019. Upon conversion, the Notes will be converted into cash, shares of our common stock, or a combination of cash and shares of our common stock, at our election. The Notes will be subject to redemption at our option, on or after October 15, 2022, in whole or in part, if the conditions described below are satisfied. The Notes will mature on October 15, 2025, unless earlier converted, redeemed or repurchased in accordance with their terms. Subject to satisfaction of certain conditions and during the periods described below, the Notes may be converted at an initial conversion rate of 63.0731 shares of common stock per $1$1 principal amount of the Notes (equivalent to an initial conversion price of approximately ~~$15.85~~$15.85 per share of common stock).

Holders of the Notes may convert all or any portion of their Notes, in multiples of $1$1 principal amount, at their option at any time prior to the close of business on the business day immediately preceding June 15, 2025 only under the following circumstances:

(1)

during any calendar quarter commencing after the calendar quarter ending on December 31, 2018 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to ~~130%~~130% of the conversion price for the Notes on each applicable trading day;

(2)

during the five business day period immediately after any five consecutive trading day period (the “Measurement Period”) in which the trading price per ~~$1,000~~$1,000 principal amount of Notes for each trading day of the Measurement Period was less than ~~98%~~98% of the product of the last reported sale price of our common stock and the conversion rate on each such trading day;

(3)

if we call the Notes for redemption, until the close of business on the business day immediately preceding the redemption date; or

(4)

upon the occurrence of specified corporate events as described within the indenture governing the Notes.

As of ~~March 31,~~June 30, 2021, none of the above circumstances had occurred and as such, the Notes could not have been converted.

We may not redeem the Notes prior to October 15, 2022. On or after October 15, 2022, we may redeem for cash all or part of the Notes at our option if the last reported sale price of our common stock equals or exceeds ~~130%~~130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending within 5 trading days prior to the date on which we send any notice of redemption. The redemption price will be ~~100%~~100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest, if any. In addition, calling any convertible note for redemption will constitute a make-whole fundamental change with respect to that convertible note, in which case the conversion rate applicable to the conversion of that convertible note, if it is converted in connection with the redemption, will be increased in certain circumstances.

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The outstanding balance of the Notes consisted of the following (in thousands):


	March 31, 2021			December 31, 2020			June 30, 2021			December 31, 2020
Liability component
Principal	$	172,500		$	172,500		$	172,500		$	172,500
Less: debt discount and issuance costs, net		(3,796	)		(54,572	)		(3,601	)		(54,572	)
Net carrying amount	$	168,704		$	117,928		$	168,899		$	117,928
Equity component	$	—		$	65,641		$	0		$	65,641

We determined the expected life of the Notes was equal to its seven-year term. The effective interest rate on the Liability Component of the Notes was ~~11.85%~~11.85%. As of ~~March 31,~~June 30, 2021, the “if-converted value” did not exceed the remaining principal amount of the Notes. The fair value of the Notes was determined based on data points other than quoted prices that are observable, either directly or indirectly, and has been classified as Level 2 within the fair value hierarchy. The fair value of the Notes, which differs from their carrying value, is influenced by market interest rates, our stock price and stock price volatility. The estimated fair value of the Notes as of ~~March 31,~~June 30, 2021 and December 31, 2020 was approximately ~~$179.6~~$173.1 million and ~~$215.8~~$215.8 million, respectively.

The following table sets forth total interest expense recognized related to the Notes for the periods indicated (in thousands):


	Three Months Ended March 31,					For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2021		2020			2021		2020		2021		2020
Contractual interest expense	$	1,294		$	1,294	$	1,294	$	1,294	$	2,588	$	2,588
Amortization of debt discount		—			1,821		0		1,911		0		3,732
Amortization of debt issuance costs		191			91		195		96		386		187
Total interest expense	$	1,485		$	3,206	$	1,489	$	3,301	$	2,974	$	6,507

Future minimum payments on the Notes as of ~~March 31,~~June 30, 2021 were as follows (in thousands):


Years ended December 31,	Future Minimum Payments			Future Minimum Payments
2021	$	5,175		$	2,588
2022		5,175			5,175
2023		5,175			5,175
2024		5,175			5,175
2025		177,675			177,675
Total minimum payments	$	198,375		$	195,788
Less: interest and issuance costs		(29,671	)		(26,889	)
Convertible senior notes	$	168,704		$	168,899

Deferred Royalty Obligation

In September 2019, we entered into a ~~deferred royalty obligation pursuant to a~~ Revenue Interest Financing Agreement (“~~deferred royalty obligation”~~the Revenue Interest Agreement”) with HealthCare Royalty Partners III, L.P. and HealthCare Royalty Partners IV, L.P. (“HCR”) ~~whereby~~. In June 2021, we, and certain of our subsidiaries, entered into an amendment of the Revenue Interest Agreement (the “Amended Revenue Interest Agreement”) with, among others, HCR.

We received $75.0 million, less certain transaction expenses, upon closing of the Revenue Interest Agreement (the “First Investment Amount”) and $60.0 million upon closing of the Amended Revenue Interest Agreement (the “Second Investment Amount” and together with the First Investment Amount, the “deferred royalty obligation”). The Amended Revenue Interest Agreement provides that we will also receive an additional $20.0 million (the “Third Investment Amount”) and an additional $20.0 million (the “Fourth Investment Amount” and together with the First Investment Amount, the Second Investment Amount and the Third Investment Amount, the “Investment Amount”) upon the achievement of certain prespecified development and commercial milestones.

In exchange for the above payments, HCR ~~receives~~will receive payments from us at a tiered percentage (the “Applicable Tiered Percentage”) of net revenues of ~~XPOVIO~~selinexor and any of our other future products, including worldwide net product sales and upfront payments, milestones, and royalties. The Applicable Tiered ~~Percentages are~~Percentage is subject to reduction in the future if a target based on cumulative U.S. net sales of selinexor is met. Total payments to HCR are capped at ~~185%~~185% of the Investment Amount. We received $75.0 million upon closing (the “First Investment Amount”) and have the right to receive an additional $75.0 million (the “Second Investment Amount” and together with the First Investment Amount, the “Investment Amount”) upon the achievement of regulatory and commercial milestones and subject to the approval of both parties and customary closing conditions.

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If HCR has not received ~~65%~~65% of the First Investment Amount by December 31, 2022, 100% of the First Investment Amount and 65% of the Second Investment amount by December 31, 2024, or ~~100%~~100% of both the First Investment Amount and the Second Investment Amount by September 30, 2026, we must make a cash payment sufficient to gross up the payments to such minimum amounts. In the event that the Third Investment Amount is funded and HCR has not received 65% of the First Investment Amount by December 31, 2022, 100% of the First Investment Amount and 65% of each of the Second Investment Amount and the Third Investment Amount by December 31, 2024, or 100% of each of the First Investment Amount, Second Investment Amount and Third Investment Amount by September 30, 2026, we must make a cash payment sufficient to gross up the payments to such minimum amounts. Further, in the event that both the Third Investment Amount and Fourth Investment Amount are funded and HCR has not received 65% of the First Investment Amount by December 31, 2022, 100% of the First Investment Amount and 65% of each of the Second Investment Amount, Third Investment Amount and Fourth Investment Amount by December 31, 2024, or 100% of the Investment Amount by ~~December 31, 2024,~~September 30, 2026, we must make a cash payment sufficient to gross up the payments to such minimum amounts.

As the repayment of the funded amount is contingent upon worldwide net product sales and upfront payments, milestones, and royalties, the repayment term may be shortened or extended depending on actual worldwide net product sales and upfront payments, milestones, and royalties. The repayment period commenced on October 1, 2019 for the First Investment Amount and on July 1, 2021 for the Second Investment Amount, and expires on the earlier of (i) the date in which HCR has received cash payments totaling an aggregate of ~~185%~~185% of the Investment Amount or (ii) the legal maturity date of October 1, 2031. If HCR has not received payments equal to ~~185%~~185% of the Investment Amount by the twelve-year anniversary of the initial closing date, we will be required to pay an amount equal to the Investment Amount plus a specific annual rate of return less payments previously received by HCR. In the event of a change of control, we are obligated to pay HCR an amount equal to ~~185%~~185% of the Investment Amount less payments previously received by HCR. In addition, upon the occurrence of an event of default, including, among others, our failure to pay any amounts due to HCR under the deferred royalty obligation, insolvency, our failure to pay indebtedness when due, the revocation of regulatory approval of XPOVIO in the U.S. or our breach of any covenant contained in the Amended Revenue Interest ~~Financing~~ Agreement and our failure to cure the breach within the prescribed time frame, we are obligated to pay HCR an amount equal to ~~185%~~185% of the Investment Amount less payments previously received by HCR. In addition, upon an event of default, HCR may exercise all other rights and remedies available under the Amended Revenue Interest ~~Financing~~ Agreement, including foreclosing on the collateral that was pledged to HCR, which consists of all of our present and future assets relating to XPOVIO. As of ~~March 31,~~June 30, 2021, we have made ~~$8.5~~$10.1 million in payments to HCR.

We have evaluated the terms of the deferred royalty obligation and concluded that the features of both the First Investment Amount and Second Investment Amount are similar to those of a debt instrument. Accordingly, we have accounted for the transaction as long-term ~~debt.~~ debt and presented it as a deferred royalty obligation on our condensed consolidated balance sheet. We have accounted for the Amended Revenue Interest Agreement as a debt modification under ASC 740-50, Debt - Modifications and Extinguishments.

We have further evaluated the terms of the debt and determined that the repayment of ~~185%~~185% of the Investment Amount, less any payments made to date, upon a change of control is an embedded derivative that requires bifurcation from the debt instrument and fair value recognition. We determined the fair value of the derivative using an option pricing Monte Carlo simulation model taking into account the probability of change of control occurring and potential repayment amounts and timing of such payments that would result under various scenarios, as further described in Note 6, “Fair Value of Financial Instruments” to our condensed consolidated financial statements. The aggregate fair value of the embedded derivative liability was ~~$1.8~~$2.1 million as of ~~both March 31,~~June 30, 2021 and $1.8 million as of December 31, 2020. We recorded a $0.6 million gain on the embedded derivative associated with the First Investment Amount in other (income) expense, net during the three and six months ended June 30, 2021 and did 0t incur a gain or loss on the embedded derivative during the three and six months ended June 30, 2020. We will remeasure the embedded derivative to fair value each reporting period until the time the features lapse and/or termination of the deferred royalty obligation.

The effective interest rate as of ~~March 31,~~June 30, 2021 was ~~18.0%~~approximately 19.0%. In connection with the ~~deferred royalty obligation,~~First Investment Amount, we incurred debt issuance costs totaling ~~$1.4~~$1.4 million. Debt issuance costs have been netted against the debt and are being amortized over the estimated term of the debt using the effective interest method, adjusted on a prospective basis for changes in the underlying assumptions and inputs. The assumptions used in determining the expected repayment term of the debt and amortization period of the issuance costs requires that we make estimates that could impact the short and long-term classification of these costs, as well as the period over which these costs will be amortized.

The carrying value of the deferred royalty obligation at ~~each~~June 30, 2021 was $130.3 million based on $135.0 million of ~~March 31, 2021~~proceeds, net of the fair value of the bifurcated embedded derivative liability upon execution of the Revenue Interest Agreement and the Amended Revenue Interest Agreement, and debt issuance costs incurred. The carrying value of the deferred royalty obligation at December 31, 2020 was ~~$71.3~~$71.3 million based on ~~$75.0~~$75.0 million of proceeds, net of the fair value of the bifurcated embedded derivative liability upon execution of the Revenue Interest Financing Agreement, and debt issuance costs incurred. The carrying value of the deferred royalty obligation ~~approximates~~approximated fair value at ~~March 31,~~June 30, 2021 and December 31, 2020 and was measured using Level 3 inputs. The estimated fair market value was calculated using an option pricing Monte Carlo simulation model with inputs consistent with

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those used in determining the embedded derivative values as described in Note 6, “Fair Value of Financial Instruments” to our condensed consolidated financial statements.

Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion and analysis of our financial condition and results of operations together with our financial statements and related notes appearing elsewhere in this quarterly report and the audited financial information and the notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2020, as filed with the Securities and Exchange Commission (“SEC”) on February 24, 2021 ("(“Annual ~~Report"~~Report”).

This Quarterly Report on Form 10-Q, including the following discussion, contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this Quarterly Report on Form 10-Q, including statements regarding possible achievement of discovery and development milestones, including regulatory submissions and approvals, our future discovery and development efforts, our commercialization efforts, our collaborations and partnering agreements with third parties, our strategy, our future operations, financial position and revenues, projected costs, prospects, plans and objectives of management, are forward looking statements. The words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “plan,” “predict,” “project,” “target,” “potential,” “will,” “would,” “could,” “should,” “continue” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. You also can identify these forward-looking statements by the fact that they do not relate strictly to historical or current facts. Forward-looking statements are not guarantees of future performance and our actual results could differ materially from the plans, intentions, expectations or results discussed in the forward-looking statements. There are a number of important risks and uncertainties that could cause actual results or events to differ materially from those indicated by forward-looking statements. These risks and uncertainties include, but are not limited to, those described in Part II, Item 1A - Risk Factors of this Quarterly Report on Form 10-Q. As a result of these and other factors, we may not actually achieve the plans, intentions, expectations or results disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make. We do not assume any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

We are a commercial-stage pharmaceutical company pioneering novel cancer therapies and dedicated to the discovery, development and commercialization of first-in-class drugs directed against nuclear transport for the treatment of cancer and other diseases. Our scientific expertise is based upon an understanding of the regulation of intracellular communication between the nucleus and the cytoplasm. We have discovered and are developing and commercializing novel, small molecule Selective Inhibitor of Nuclear Export (“SINE”) compounds that inhibit the nuclear export protein exportin 1 (“XPO1”). These SINE compounds, representing a new class of drug candidates with a novel mechanism of action that have the potential to treat a variety of diseases with high unmet medical need, were the first oral XPO1 inhibitors to receive marketing approval. Our lead asset, XPOVIO® (selinexor), received its initial U.S. approval from the ~~FDA~~U.S. Food and Drug Administration (“FDA”) in July 2019 and is currently approved and marketed for the following indications:

The commercialization of XPOVIO, for both the multiple myeloma and DLBCL indications, is currently supported by sales representatives and nurse liaisons, and a market access team as well as KaryForward™, an extensive patient and healthcare provider support program. Our commercial efforts are also supplemented by patient support initiatives coordinated by our dedicated network of participating specialty pharmacy providers. We plan to continue to educate physicians, other healthcare providers and patients about XPOVIO’s clinical profile and unique mechanism of action as we expand XPOVIO into the second-line plus multiple myeloma market and continue to penetrate the third-line DLBCL market.

XPOVIO also received its first regulatory approval outside the U.S. with an approval in Israel received in February 2021 by our partner Promedico Ltd., a member of the Neopharm Group, for the treatment of patients with multiple myeloma and DLBCL. In addition, in March 2021 and May 2021, the European Commission and the United Kingdom’s Medicines & Healthcare Products Regulatory Agency granted conditional approval, respectively, of NEXPOVIO®(selinexor), the brand name for selinexor in Europe and the United Kingdom, based on the results of the Phase 2b STORM Study, which evaluated selinexor in combination with dexamethasone for the treatment of multiple myeloma in adult patients who have received at least four prior therapies and whose disease is refractory to at least two PIs, two IMiDs and an anti-CD38 monoclonal antibody, and who have demonstrated disease progression on the last therapy. Based on our submission through the centralized procedure, ~~this~~the European Commission’s marketing authorization is valid in all 27 European Union member countries as well as the European Economic Area countries of Iceland, Liechtenstein and Norway. In addition, in April 2021, the European Medicines Agency validated our Type II variation marketing authorization application based on the data from the Phase 3 BOSTON Study, which evaluated once-weekly selinexor in combination with once-weekly Velcade®(bortezomib) and low-dose dexamethasone compared to standard twice-weekly Velcade® plus low-dose dexamethasone in patients with multiple myeloma who have received one to three prior lines of therapy. We expect that the review of our application will be completed byin the ~~fourth quarter~~first half of ~~2021.~~2022. Most recently, on July 30, 2021 our partner, Antengene Therapeutics Limited (“Antengene”), announced that the South Korean Ministry of Food and Drug Safety approved its New Drug Application for selinexor for the treatment of patients with multiple myeloma and DLBCL.

Our focus is on marketing XPOVIO in its currently approved indications as well as seeking the regulatory approval and potential commercialization of selinexor as an oral agent in additional cancer indications with significant unmet medical need. We plan to continue to conduct clinical trials and to seek additional approvals for the use of selinexor as a single agent or in combination with other oncology therapies to expand the patient populations that are eligible for treatment with selinexor. Thus, we are advancing our clinical development program for selinexor in the areas of multiple hematological malignancies and solid tumors, among ~~others.~~others, including our SIENDO study evaluating once weekly selinexor versus placebo as maintenance therapy in patients with endometrial cancer after first- or second-line chemotherapy. Additionally, we have initiated and expect ~~that~~to initiate a number of ~~selinexor~~key clinical trials ~~will be initiated~~ in 2021, including a Phase 3 study evaluating selinexor in combination with pomalidomide in patients with relapsed or refractory multiple myeloma as well as new or expanded Phase 1 and 2 studies evaluating (i) selinexor in patients with a variety of hematologic and solid tumor indications, including myelofibrosis, metastatic melanoma ~~lung~~and colorectal cancer and ~~colorectal cancer.~~(ii) eltanexor in patients with myelodysplastic syndrome. A number of these studies will be investigating the treatment of selinexor in combination with other standard of care anti-cancer drugs.

On May 3, 2021, ~~we announced that~~ Richard Paulson ~~M.B.A. will succeed~~succeeded Michael G. Kauffman ~~M.D., Ph.D.~~ as Chief Executive Officer and Sharon Shacham ~~Ph.D., M.B.A,~~ as ~~President, effective May 3, 2021.~~President. Both Mr. Paulson ~~will also remain a member~~and Dr. Kauffman continue to be members of the Board of Directors. In addition, Dr. Kauffman ~~will continue to advance the Company’s mission and remain a member of our Board of Directors. In addition, he will~~has also ~~take~~taken on a new role in the Company as Senior Clinical Advisor. ~~In this capacity, he will help guide the clinical development for our robust pipeline of programs, with a focus on solid tumor indications.~~ Dr. Shacham ~~will continue~~continues in her role as Chief Scientific Officer, overseeing research, development and regulatory affairs.

On November 24, 2020, we entered in an asset purchase agreement (the “Asset Purchase Agreement”) with Neumedicines Inc. (“Neumedicines”). Pursuant to the Asset Purchase Agreement, we agreed to acquire certain assets from Neumedicines, including HemaMax™, a proprietary recombinant human interleukin 12 (“IL-12”). The acquisition of the acquired assets closed on July 22, 2021 (the “Closing”), at which time we paid $6.0 million in cash and issued 150,000 unregistered shares of our common stock to Neumedicines for the acquired assets under the Asset Purchase Agreement. Further, we will owe Neumedicines up to $65.0 million in royalty payments on net product sales of IL-12 products and an additional 75,000 shares of our common stock as well as other contingent cash payments upon the satisfaction of certain development milestones. Contemporaneously with the Closing, we entered into a license agreement with Libo Pharma Corp. (“Libo”) under which we granted to Libo an exclusive license to manufacture, develop and commercialize IL-12 products in certain countries in Asia, Africa and Oceania.

In June 2021, we, and certain of our subsidiaries, entered into an amendment of the September 2019 Revenue Interest Financing Agreement (“Revenue Interest Agreement” and as amended, the “Amended Revenue Interest Agreement”) with, among others, HealthCare Royalty Partners III, L.P. and HealthCare Royalty Partners IV, L.P. (“HCR”). We received $60.0 million, less certain transaction expenses, upon closing of the Amended Revenue Interest Agreement on June 23, 2021. For additional information on the Amended Revenue Interest Agreement, see Note 11 to the condensed consolidated financial statements included under Part I, Item I of this Quarterly Report on Form 10-Q.

As of ~~March 31,~~June 30, 2021, we had an accumulated deficit of ~~$1.1~~$1.2 billion. We had net losses of ~~$57.4~~$111.0 million and ~~$52.9~~$99.4 million for the ~~three~~six months ended ~~March 31,~~June 30, 2021 and 2020, respectively. We anticipate that our expenses will continue to increase as compared to prior periods as we continue to commercialize XPOVIO in the U.S. and engage in activities to prepare for the potential commercialization of additional indications for selinexor and the potential approval of our other product candidates, including ~~due to~~ the impact of increased headcount, to support our clinical and commercialization activities and expanded infrastructure.

The COVID-19 pandemic has and will continue to affect economies and businesses around the world. We continue to closely monitor the impact of the COVID-19 pandemic on all aspects of our business, including the impact on our employees, patients and

business operations. We have and may continue to experience disruptions in the future that could impact our results of operations, including product revenue, and financial condition. Although we do not currently expect that the ongoing COVID-19 pandemic will have a material impact on our business plans or results of operations, we are unable to predict the impact that the COVID-19 pandemic will have on our operating results and financial condition due to numerous uncertainties. These uncertainties include the availability and effectiveness of vaccines and therapeutics, the spread of more contagious variants of the virus, the duration and scope of the pandemic, ~~the severity of the virus,~~ governmental, business or other actions, travel restrictions and social distancing, business closures or business disruptions, or changes to our operations, among others. We will continue to monitor the COVID-19 situation closely and intend to follow health and safety guidelines as they evolve. Further, the impacts of a potential worsening of global economic conditions and the continued disruptions to, and volatility in, the credit and financial markets, as well as other unanticipated consequences remain unknown. The situation surrounding the COVID-19 pandemic remains fluid and continues to rapidly evolve, and we are actively managing our response and assessing potential impacts to our operating results and financial condition, as well as adverse developments in our business. For further information regarding the impact of the COVID-19 pandemic on us, see Item 1A - Risk Factors included in this Quarterly Report on Form 10-Q.

We believe that several accounting policies are important to understanding our historical and future performance. We refer to these policies as “critical” because these specific areas generally require us to make judgments and estimates about matters that are uncertain at the time we make the estimate, and different estimates - which also would have been reasonable - could have been used, which would have resulted in different financial results.

There were no changes to the critical accounting policies we identified in our Annual Report. It is important that the discussion of our operating results that follows be read in conjunction with the critical accounting policies disclosed in our Annual Report.

Comparison of the Three Months Ended ~~March 31,~~June 30, 2021 and ~~March 31,~~June 30, 2020


	For the Three Months Ended March 31,												Three Months Ended June 30,
	2021			2020			$ Change			% Change			2021			2020			$ Change			% Change
	(in thousands)												(in thousands)
Product revenue, net	$	21,731		$	16,061		$	5,670			35	%	$	20,179		$	18,601		$	1,578			8	%
License and other revenue		1,529			2,077			(548	)		(26	)%		2,422			14,913			(12,491	)		(84	)%
Operating expenses:
Cost of sales		933			819			114			14	%		1,138			396			742			187	%
Research and development		37,050			33,997			3,053			9	%		33,981			42,594			(8,613	)		(20	)%
Selling, general and administrative		37,650			30,678			6,972			23	%		36,530			30,843			5,687			18	%
Loss from operations		(52,373	)		(47,356	)		(5,017	)		11	%		(49,048	)		(40,319	)		(8,729	)		22	%
Other expense, net		(4,892	)		(5,509	)		617			(11	)%		(4,400	)		(5,970	)		1,570			(26	)%
Loss before income taxes		(57,265	)		(52,865	)		(4,400	)		8	%		(53,448	)		(46,289	)		(7,159	)		15	%
Income tax provision		(149	)		(66	)		(83	)		126	%		(134	)		(137	)		3			(2	)%
Net loss	$	(57,414	)	$	(52,931	)	$	(4,483	)		8	%	$	(53,582	)	$	(46,426	)	$	(7,156	)		15	%

Product revenue, net. We recognized ~~$21.7~~$20.2 million and ~~$16.1~~$18.6 million of net product revenue in the three months ended ~~March 31,~~June 30, 2021 and 2020, respectively, from U.S. commercial sales of XPOVIO. We expect net product revenue to increase in the second ~~quarter~~half of 2021 as compared to the first ~~quarter~~half of 2021 ~~following the December 2020 FDA approval of~~as we continue to educate healthcare professionals on the expanded XPOVIO indication based on the BOSTON ~~Study.~~Study, which was approved in December 2020.

License and other revenue. We recognized ~~$1.5~~$2.4 million and ~~$2.1~~$14.9 million of license and other revenue for the three months ended ~~March 31,~~June 30, 2021 and 2020, respectively. During the three months ended ~~March 31,~~June 30, 2021, we recognized ~~$0.5~~$1.0 million pursuant to our license agreement with Anivive Lifesciences, Inc.~~, $0.3~~ and $1.4 million of revenue associated with named patient programs. During the three months ended June 30, 2020, we recognized $12.7 million pursuant to our license agreement with Antengene ~~Therapeutics Limited~~and $2.2 million upon reacquisition of the exclusive development and commercial rights from Ono Pharmaceutical Co., Ltd. (“~~Antengene”~~Ono”),. We expect license and ~~$0.7~~other revenue will increase in the second half of 2021 as compared to the first half of 2021, due primarily to $10.0 million in milestone payments expected to be received from Antengene following the July 2021 approval of ~~other revenue. During~~selinexor for the ~~three months ended March 31, 2020, we recognized $1.1 million pursuant to our license agreement~~treatment of patients with ~~Antengene, $0.5 million pursuant to a license agreement with a distributor,~~multiple myeloma and ~~$0.5 million related to clinical supply provided to various partners, as well as grant revenue pursuant to a government grant arrangement.~~DLBCL in South Korea.

Cost of sales. Cost of sales includes the cost of producing and distributing inventories that are related to U.S. XPOVIO product revenue during the respective period (including salary-related and stock-based compensation expenses for employees involved with XPOVIO production and distribution) and third-party royalties payable on our net product revenue for XPOVIO. We began capitalizing XPOVIO inventory costs during the third quarter of 2019 subsequent to FDA approval, as our expectation was that such costs will be recoverable through commercialization of XPOVIO. Prior to the capitalization of XPOVIO inventory costs, such costs were recorded as research and development expenses in the period incurred. During the three months ended ~~March 31,~~June 30, 2021 and 2020, we recorded ~~$0.9~~$1.1 million and ~~$0.8~~$0.4 million, respectively, of cost of sales, including $0.1 million ~~and $0.7 million, respectively,~~ related to ~~royalties.~~royalties in each of the three months ended June 30, 2021 and 2020. The cost of sales

during the three months ended ~~March 31,~~June 30, 2021 and 2020 only reflects a portion of the costs related to the manufacturing of XPOVIO and related materials, since, prior to FDA approval, these costs were expensed. The manufacturing costs of XPOVIO on-hand upon FDA approval amounted to approximately $2.8 million. At ~~March 31,~~June 30, 2021, we had $2.1 million of this previously expensed XPOVIO and related material on-hand. We expect to utilize zero cost inventory with respect to XPOVIO for an extended period of time. We expect cost of sales to remain relatively consistent in the second ~~quarter~~half of 2021 compared to the first ~~quarter~~half of 2021.

Research and development expense. Research and development expense ~~increased~~decreased approximately ~~$3.1~~$8.6 million to ~~$37.1 million for the three months ended March 31, 2021 from approximately~~ $34.0 million for the three months ended ~~March 31,~~June 30, 2021 from approximately $42.6 million for the three months ended June 30, 2020. The ~~increase~~decrease was primarily related to:

We expect our research and development expense to increase overall in the second ~~quarter~~half of 2021 compared to the first ~~quarter~~half of 2021, with variability from quarter to quarter, as we continue clinical development of selinexor in our lead indications with a focus on regulatory submissions for selinexor. In addition, in connection with the Closing of the Asset Purchase Agreement with Neumedicines, on July 22, 2021, we paid $6.0 million in cash and issued 150,000 unregistered shares of our common stock, to Neumedicines.

Selling, general and administrative expense. Selling, general and administrative expense increased approximately ~~$7.0~~$5.7 million to ~~$37.7~~$36.5 million for the three months ended ~~March 31,~~June 30, 2021 from approximately ~~$30.7~~$30.8 million for the three months ended ~~March 31,~~June 30, 2020. The increase was primarily related to:

We expect our selling, general and administrative expenses to remain relatively consistent in the second ~~quarter~~half of 2021 compared to the first ~~quarter~~half of 2021 as we continue to support our operating and commercial activities related to sales and marketing of XPOVIO.

Other Expense, net. Other expense, net decreased from ~~$5.5~~$6.0 million for the three months ended ~~March 31,~~June 30, 2020 to ~~$4.9~~$4.4 million for the three months ended ~~March 31,~~June 30, 2021. The net decrease of approximately ~~$0.6~~$1.6 million was primarily due to a decrease in interest expense of ~~$1.4~~$1.8 million, a $0.6 million realized gain resulting from the mark-to-market adjustment on our embedded derivative liability related to our deferred royalty obligation, offset by a decrease in interest income of $0.7 million and $0.1 million in foreign currency ~~translation~~ fluctuation. Interest expense related to our Revenue Interest ~~Financing~~ Agreement ~~(“deferred royalty obligation”) increased $0.3 million~~remained consistent quarter over quarter, and interest expense related to our 3.00% senior convertible notes due 2025 (the “Notes”) decreased ~~$1.7~~$1.8 million, as a result of the adoption of ASU No. 2020-06, Debt—Debt with Conversion and Other Options and Derivatives and Hedging—Contracts in Entity’s Own Equity(“ASU 2020-06”), on January 1, 2021. Post adoption of ASU 2020-06, we are no longer amortizing the debt discount to non-cash interest expense, and therefore, interest expense in the ~~quarter,~~three months ended June 30, 2021, related to the Notes, ~~decreased.~~decreased as compared to the three months ended June 30, 2020. We expect other expense, net to increase in the second half of 2021 compared to the first half of 2021 due to the increased royalty rates under the Amended Revenue Interest Agreement.

Product revenue, net. We recognized $41.9 million and $34.7 million of net product revenue in the six months ended June 30, 2021 and 2020, respectively, from U.S. commercial sales of XPOVIO.

License and other revenue. We recognized $4.0 million and $17.0 million of license and other revenue for the six months ended June 30, 2021 and 2020, respectively. During the six months ended June 30, 2021, we recognized $1.5 million pursuant to our license agreement with Anivive Lifesciences, Inc., $0.3 million pursuant to the license agreement with Antengene, and $2.2 million of revenue associated with named patient programs. During the six months ended June 30, 2020, we recognized $13.8 million pursuant to the license agreement with Antengene, $2.2 million upon reacquisition of the exclusive development and commercial rights from Ono, and $1.0 million related to clinical supply provided to various partners, as well as grant revenue pursuant to a government grant arrangement.

Cost of sales. During the six months ended June 30, 2021 and 2020, we recorded $2.1 million and $1.2 million, respectively, of cost of sales, including $0.2 million and $0.9 million, respectively, related to royalties.

Research and development expense. Research and development expense decreased approximately $5.6 million to $71.0 million for the six months ended June 30, 2021 from approximately $76.6 million for the six months ended June 30, 2020. The decrease was primarily related to:

Selling, general and administrative expense. Selling,general and administrative expense increased approximately $12.7 million to $74.2 million for the six months ended June 30, 2021 from approximately $61.5 million for the six months ended June 30, 2020. The increase was primarily related to:

Other Expense, net. Other expense, net decreased from $11.5 million for the six months ended June 30, 2020 to $9.3 million for the six months ended June 30, 2021. The net decrease of approximately $2.2 million was primarily due to a decrease in interest expense of $3.2 million, a $0.6 million realized gain resulting from the mark-to-market adjustment on our embedded derivative liability related to our deferred royalty obligation, offset by a decrease in interest income of $1.4 million and $0.2 million in foreign currency translation fluctuation.Interest expense related to our Revenue Interest Agreement increased $0.3 million and interest expense related to the Notes decreased $3.5 million, as a result of the adoption of ASU 2020-06 on January 1, 2021. Post adoption of

ASU 2020-06, we are no longer amortizing the debt discount to non-cash interest expense, and therefore, interest expense in the six months ended June 30, 2021, related to the Notes, decreased as compared to the six months ended June 30, 2020.

During the third quarter of 2019, we began generating revenues from product sales, as XPOVIO first became commercially available in the U.S. in July 2019. ~~While we began to generate revenue from the sales of XPOVIO in July 2019, to~~To date, we have financed our operations through a combination of product revenue sales, private placements of our preferred stock, proceeds from our initial public offering and follow-on offerings of common stock, proceeds from the issuance of convertible debt, proceeds pursuant to the deferred royalty obligation and related amendment, and cash generated from our business development ~~activities.~~activities.

As of ~~March 31,~~June 30, 2021, our principal source of liquidity was ~~$232.0~~$237.9 million of cash, cash equivalents and investments. We have had recurring losses and incurred a loss of ~~$57.4~~$111.0 million for the ~~three~~six months ended ~~March 31,~~June 30, 2021. Net cash used in operations for the ~~three~~six months ended ~~March 31,~~June 30, 2021 was ~~$52.9~~$108.6 million. We expect that our cash, cash equivalents and investments at ~~March 31,~~June 30, 2021 will be sufficient to fund our current operating plans and capital expenditure requirements for at least twelve months from the date of issuance of the financial statements contained in this Quarterly Report on Form 10-Q.

On June 23, 2021, we and certain of our subsidiaries entered into an amendment to the Revenue Interest Agreement. Pursuant to the Revenue Interest Agreement, HCR paid us $75.0 million, less certain transaction expenses, on September 27, 2019 and pursuant to the Amended Revenue Interest Agreement, HCR paid us $60.0 million, less certain transaction expenses, on June 23, 2021. The Amended Revenue Interest Agreement also provides that we will be entitled to receive two additional payments of $20.0 million each upon the achievement of certain prespecified development and commercial milestones and subject to certain conditions.For additional information on the Amended Revenue Interest Agreement, see Note 11 to the condensed consolidated financial statements included under Part I, Item I of this Quarterly Report on Form 10-Q.

On May 5, 2020, we entered into Amendment No. 1 to the Open Market Sale Agreement, dated August 17, 2018 (the “Open Market Sale Agreement”) with Jefferies LLC, as agent (“Jefferies”) pursuant to which we increased the maximum aggregate offering price of shares of our common stock that we may issue and sell from time to time through Jefferies, by $100.0 million from $75.0 million to up to $175.0 million. We did not sell shares under the Open Market Sale Agreement during the three months ended June 30, 2021. We sold an aggregate of 638,341 shares under the Open Market Sale Agreement, for net proceeds of approximately $9.9 million, during the ~~three~~six months ended ~~March 31,~~June 30, 2021.

On March 6, 2020, we completed a follow-on offering under our shelf registration statement on Form S-3 pursuant to which we issued an aggregate of 7,187,500 shares of common stock, which included the full exercise of the underwriters’ option to purchase

additional shares, at a public offering price of $24.00 per share. We received aggregate net proceeds of approximately $161.8 million from the offering after deducting the underwriting discounts and commissions and other offering expenses.

On September 14, 2019, we entered into a deferred royalty obligation, with HealthCare Royalty Partners III, L.P. and HealthCare Royalty Partners IV, L.P. (“HCR”). Pursuant to the deferred royalty obligation, HCR paid us $75.0 million, less certain transaction expenses, at the initial closing, which occurred on September 27, 2019, as disclosed in Note 11 to the condensed consolidated financial statements included under Part I, Item 1 of this Quarterly Report on Form 10-Q.

The following table provides information regarding our cash flows (in thousands):

Operating activities. The net cash used in operating activities in both periods resulted primarily from our net losses adjusted for non-cash charges and changes in the components of working capital. The increase in cash used in operating activities during the ~~three~~six months ended ~~March 31,~~June 30, 2021, compared to the ~~three~~six months ended ~~March 31,~~June 30, 2020, was primarily driven by our increased loss from operations during that period.

Investing activities. The net cash provided by (used in) investing activities during the ~~three~~six months ended ~~March 31,~~June 30, 2021, compared to the ~~three~~six months ended ~~March 31,~~June 30, 2020, primarily reflects a ~~$68.1~~$171.0 million decrease in the purchases of investments, coupled with a ~~$21.5~~$25.1 million increase in proceeds from the sales and maturities of investments.

Financing activities. The net cash provided by financing activities for the ~~three~~six months ended ~~March 31,~~June 30, 2021 compared to the ~~three~~six months ended ~~March 31,~~June 30, 2020, reflects a decrease of ~~$154.2~~$94.1 million. The decrease was primarily due to our $60.0 million cash inflow from the Amended Revenue Interest Agreement, coupled with $9.9 million in net cash proceeds from the sale of shares of our common stock under our Open Market Sale Agreement in the first ~~quarter~~six months of 2021, compared to net cash proceeds of ~~$162.1~~$161.8 million from the sale of shares of our common stock from the follow-on offering under our shelf registration statement on Form S-3 during the first ~~quarter~~six months of 2020. There was also a decrease in proceeds from the exercise of stock options in the first ~~three~~six months of 2021 compared to the first ~~three~~six months of 2020, of ~~$2.0~~$2.2 million.

We are party to an operating lease of 98,502 square feet of office and research space in Newton, Massachusetts with a term through September 30, 2025 (the “Newton, MA Lease”). Pursuant to the Newton, MA Lease, we have provided a security deposit in the form of a cash-collateralized letter of credit in the amount of $0.6 million. The amount is classified within long-term restricted cash. We expect lease costs under this commitment to total $3.3 million in 2021 and increase annually; we expect total lease costs of approximately $17.2 million.

In addition, we are party to certain short-term leases having a term of twelve months or less at the commencement date. We recognize short-term lease expense on a straight-line basis and do not record a related right-of use asset or lease liability for such leases. These costs were insignificant for the quarters ended ~~March 31,~~June 30, 2021 and December 31, 2020.

We have contractual obligations under our Notes and under our ~~deferred royalty obligation with HCR~~Revenue Interest Agreement as disclosed in Note 11 to the condensed consolidated financial statements included under Part I, Item 1 of this Quarterly Report on Form 10-Q.

We expect our expenses to continue to increase in connection with our ongoing activities, particularly as we continue the clinical trials of, and as we seek marketing approval for, our product candidates. We also anticipate that we will continue to incur substantial expenses as we commercialize XPOVIO, both within the U.S. and on a global basis, and engage in activities to prepare for the potential approval and commercialization of additional indications for selinexor as well as our other product candidates, if approved, to the extent that such expenses are not the responsibility of any current or future partner. For a description of these expenses, please refer the risk factor entitled “We have incurred significant losses since inception, expect to continue to incur significant losses, and may never achieve or maintain profitability.” in Part II, Item 1A - Risk Factors of this Quarterly Report on Form 10-Q.

Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs or commercialization efforts. Our future capital requirements will depend on many factors, including:

Identifying potential product candidates and conducting preclinical studies and clinical trials is a time-consuming, expensive and uncertain process that takes years to complete. In addition, our product candidates for which we receive marketing approval may not achieve commercial success. Our ability to become and remain profitable depends on our ability to generate revenue. While we began to generate revenue from the sales of XPOVIO in July 2019, there can be no assurance as to the amount or timing of any such revenue, and we may not achieve profitability for several years, if at all. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives. Adequate additional financing may not be available to us on acceptable terms, or at all. We may seek additional capital due to favorable market conditions or strategic considerations, even if we believe we have sufficient funds for our current or future operating plans.

We currently expect that our cash, cash equivalents and investments as of March 31, 2021, together with the cash we expect to generate from product revenues, will be sufficient to fund our current operating plans and capital expenditure requirements for at least twelve months from the date of issuance of the financial statements contained in this Quarterly Report on Form 10-Q.

We did not have during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined under SEC rules.

We are exposed to market risk related to changes in interest rates. We had cash, cash equivalents and investments of ~~$232.0~~$237.9 million as of ~~March 31,~~June 30, 2021. Our primary exposure to market risk is interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates, particularly because the majority of our investments are in short-term securities. Due to the short-term duration of our investment portfolio and the low risk profile of our investments, an immediate 100 basis point shift in interest rates would not have a material effect on the fair market value of our investment portfolio.

We do not believe our cash, cash equivalents, restricted cash and investments have significant risk of default or illiquidity. While we believe our cash, cash equivalents and investments do not contain excessive risk, we cannot provide absolute assurance that in the future our investments will not be subject to adverse changes in securities at one or more financial institutions that are in excess of federally insured limits. Given the potential instability of financial institutions, we cannot provide assurance that we will not experience losses on these deposits and investments.

We are also exposed to market risk related to changes in foreign currency exchange rates. We contract with contract research organizations and contract manufacturing organizations that are located in Canada and Europe, which are denominated in foreign currencies. We also contract with a number of clinical trial sites outside of the U.S., and our budgets for those studies are frequently denominated in foreign currencies. We are subject to fluctuations in foreign currency rates in connection with these agreements. We do not currently hedge our foreign currency exchange rate risk.

Our management, with the participation of our President and Chief Executive Officer (principal executive officer) and ~~Senior~~Executive Vice President, Chief Financial Officer and Treasurer (principal financial officer), evaluated the effectiveness of our disclosure controls and procedures as of ~~March 31,~~June 30, 2021. The term “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), means controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to our management, including our principal executive and principal financial officers, as appropriate to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies our judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on the evaluation of our disclosure controls and procedures as of ~~March 31,~~June 30, 2021, our President and Chief Executive Officer and our ~~Senior~~Executive Vice President, Chief Financial Officer and Treasurer concluded that, as of such date, our disclosure controls and procedures were effective at the reasonable assurance level.

There were no changes in our internal control over financial reporting identified in connection with the evaluation required by Rule 13a-15(d) and 15d-15(d) of the Exchange Act that occurred during the fiscal quarter ended ~~March 31,~~June 30, 2021 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

From time to time we may face legal claims or actions in the normal course of business. We were named as a defendant in a securities class action litigation filed on July 23, 2019 in the U.S. District Court for the District of Massachusetts. The complaint was filed by the Allegheny County Employees’ Retirement System, against us and certain of our current and former executive officers and directors as well as the underwriters of our public offerings of common stock conducted in April 2017 and May 2018. This complaint was voluntarily dismissed on March 12, 2020. A second complaint was filed by Heather Mehdi on September 17, 2019, in the same court and against the same defendants with the exception of the underwriters. In April 2020, the court appointed a lead plaintiff, Myo Thant (“Plaintiff”), who filed an amended complaint on June 29, 2020. The amended complaint alleges violations of federal securities laws based on our disclosures related to the results from the Phase 2 SOPRA study and Part 2 of the Phase 2b STORM study, and seeks unspecified compensatory damages, including interest; reasonable costs and expenses, including attorneys’ and expert fees; and such equitable/injunctive relief or other relief as the court may deem just and proper. We ~~have~~ reviewed the allegations and believe they are without merit. We moved to dismiss the complaint on July 31, 2020 and concluded related briefing in September 2020. Before the court ruled on this motion to dismiss, Plaintiff filed a second amended complaint. We moved to dismiss the second amended complaint on November 2, 2020. On December 14, 2020, we were named as a defendant in a shareholder derivative suit based on allegations substantially similar to those in the class action litigation. The suit was filed in the U.S. District Court for the District of Massachusetts, by Plaintiff Vladimir Gusinsky Revocable Trust, against us and certain of our current and former executive officers and directors. On January 12, 2021, the shareholder derivative suit was stayed pending the outcome of further proceedings in the securities class action.

On July 21, 2021, the court issued a decision dismissing the securities class action complaint, and an order of dismissal was issued on the same date. We ~~intend to defend vigorously against this litigation.~~cannot predict whether Plaintiff will appeal or seek other relief from the court’s decision or the dismissal order. The shareholder derivative suit remains stayed.

Careful consideration should be given to the following risk factors, in addition to the other information set forth in this Quarterly Report on Form 10-Q and in other documents that we file with the U.S. Securities and Exchange Commission ~~("SEC"~~(“SEC”) in evaluating us and our business. Investing in our common stock involves a high degree of risk. If any of the following risks and uncertainties actually occurs, our business, prospects, financial condition and results of operations could be materially and adversely affected. The risks described below are not intended to be exhaustive and are not the only risks we face. New risk factors can emerge from time to time, and it is not possible to predict the impact that any factor or combination of factors may have on our business, prospects, financial condition and results of operations.

Our business is substantially dependent on the commercial success of XPOVIO. If we are unable to successfully commercialize our current and future indications of XPOVIO or other products or product candidates on a timely basis, including our ability to achieve widespread market acceptance by physicians, patients, third-party payors and others in the medical community, our business, financial condition and future profitability will be materially harmed.

Our business and our ability to generate product revenue from the sales of drugs that treat cancer and other diseases in humans depend heavily on our ability to successfully commercialize our lead drug, XPOVIO® (selinexor) on a global basis, in currently approved and future indications and the level of market adoption for, and the continued use of, our products and product candidates, if approved. XPOVIO is currently approved and marketed in the U.S. in multiple hematologic malignancy indications, including in combination with Velcade® (bortezomib) and dexamethasone for the treatment of patients with multiple myeloma after at least one prior therapy, in combination with dexamethasone for the treatment of patients with heavily pretreated multiple myeloma and as a monotherapy for the treatment of patients with relapsed or refractory diffuse large B-cell lymphoma (“DLBCL”). Efforts to drive adoption within the medical community and third-party payors based on the benefits of our products and product candidates require significant resources and may not be successful. The success of XPOVIO and any current or future product candidates, whether alone or in collaboration with third-parties, including achieving and maintaining an adequate level of market adoption, depends on several factors, including:

If we do not achieve one or more of these factors in a timely manner, or at all, we could experience significant delays or an inability to successfully commercialize XPOVIO or our product candidates, if approved, which would materially harm our business.

We face substantial competition, which may result in others discovering, developing or commercializing drugs before or more successfully than we do.

The discovery, development and commercialization of new drugs is highly competitive, particularly in the cancer field. We face competition with respect to XPOVIO and will face competition with respect to any product candidates that we may seek to discover and develop or commercialize in the future, from major pharmaceutical companies, specialty pharmaceutical companies, biotechnology companies, academic institutions and governmental agencies as well as public and private research institutions worldwide, many of which have significantly greater financial resources and expertise in research and development, manufacturing, preclinical studies, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. There are a number of major pharmaceutical, specialty pharmaceutical and biotechnology companies that currently market and sell drugs and/or are pursuing the development of drugs for the treatment of cancer and the other disease indications for which we are developing our product candidates. For example, BLENREP and Monjuvi® were approved by the FDA in August and July 2020, respectively. In addition, several new mechanism of actions may be introduced into the multiple myeloma market, including Car-T therapies, which may have a significant impact on the multiple myeloma landscape and our product revenues. See Item 1 under the heading Business—Competition in our Annual Report on Form 10-K for the year ended December 31, 2020 as filed with the ~~Securities and Exchange Commission (“SEC”)~~SEC on February 24, 2021 (“Annual Report”) for more information on competition.

We are initially focused on developing and commercializing our current products and product candidates for the treatment of cancer and there are a variety of available therapies marketed for cancer. In many cases, cancer drugs are administered in combination to enhance efficacy. Some of these drugs are branded and subject to patent protection, and others are available on a generic basis. Many of these approved drugs are well-established therapies and are widely accepted by physicians, patients and third-party payors. Insurers and other third-party payors may also encourage the use of generic drugs. Our products are priced at a significant premium over competitive generic drugs, which may make it difficult for us to achieve our business strategy of using our products in combination with existing therapies or replacing existing therapies with our products.

Further, our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize drugs that are or are perceived to be more effective, safer, more tolerable, more convenient and/or less costly than any of our currently approved products or product candidates or that would render our products obsolete or non-competitive. Our competitors may also obtain marketing approval from the FDA or other regulatory authorities for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a stronger market position before we are able to enter the market or preventing us from entering into a particular indication at all.

Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller and other early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These third parties compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to, or that may be necessary for, our programs.

If we are not able to compete effectively against current or potential competitors, our business will not grow and our financial condition and operations will suffer.

Clinical development is a lengthy and expensive process, with uncertain timelines and outcomes. If clinical trials of our product candidates fail to demonstrate safety and efficacy to the satisfaction of regulatory authorities or do not otherwise produce positive results, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of such product candidates.

Our long-term success depends in a large part on our ability to continue to successfully develop new indications of XPOVIO, our other product candidates or any new product candidates we may develop or acquire. Clinical testing is expensive, time consuming, difficult to design and implement, inherently uncertain as to outcome and can fail at any stage of testing. Furthermore, the failure of any product candidates to demonstrate safety and efficacy in any clinical trial could negatively impact the perception of XPOVIO or our other product candidates and/or cause the FDA or other regulatory authorities to require additional testing before any of our product candidates are approved.

We may experience numerous unforeseen events during, or as a result of, clinical trials that could delay or prevent our ability to receive marketing approval of our product candidates, including, but not limited to, the following:

The COVID-19 pandemic may continue to have an impact on our clinical trials. At this time, however, we cannot fully forecast the scope of the impact that the COVID-19 pandemic may have on our ability to, among other things, initiate trial sites, enroll and assess patients, supply study drug and report trial results. In addition, we have and may continue to experience delays in the regulatory process as a result of the COVID-19 pandemic, which may impact our approval timelines, such as delays we encountered related to our reduced access to clinical trial sites in order to complete remonitoring activities associated with our Marketing Authorization Application (“MAA”) for selinexor in multiple myeloma based on the results on the STORM study. Further, in response to the COVID-19 pandemic, the FDA issued guidance on March 18, 2020, and updated it on July 2, 2020 and January 27, 2021, to address the conduct of clinical trials during the pandemic. The guidance sets out a number of considerations for sponsors of clinical trials impacted by the pandemic, including the requirement to include in the clinical study report (or as a separate document) contingency measures implemented to manage the study, and any disruption of the study as a result of COVID-19; a list of all study participants affected by COVID-19-related study disruptions by a unique subject identifier and by investigational site, and a description of how the individual’s participation was altered; and analyses and corresponding discussions that address the impact of implemented contingency measures (e.g., participant discontinuation from investigational product and/or study, alternative procedures used to collect critical safety and/or efficacy data) on the safety and efficacy results reported for the study.

If we are required to conduct additional clinical trials or other testing of our product candidates beyond those that we currently contemplate, if we are unable to successfully complete clinical trials of our product candidates or other testing, on a timely basis or at all, and/or if the results of these trials or tests are not positive or are only modestly positive or if there are safety concerns, we may:

Further, we do not know whether clinical trials will begin as planned, will need to be restructured or will be completed on schedule, or at all, particularly as a result of the COVID-19 pandemic. Significant clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our products, allow our competitors to bring products to market before we do or impair our ability to successfully commercialize our products, which would harm our business and results of operations. In addition, many of the factors that cause, or lead to, clinical trial delays may ultimately lead to the denial of regulatory approval of our product candidates.

Even if we or our collaborators complete the necessary preclinical studies and clinical trials for our product candidates, the marketing approval process is expensive, time-consuming and uncertain and we or they may not receive approvals for the commercialization of some or all of our or their product candidates in a timely manner, or at all.

Our long-term success and ability to sustain and grow revenue depends on our and our collaborators’ ability to continue to successfully develop our product candidates and obtain regulatory approval to market our or their products both in and outside of the U.S. The FDA and comparable foreign regulatory authorities, whose laws and regulations may differ from country to country, impose substantial requirements on the development of product candidates to become eligible for marketing approval and have substantial discretion in the process and may refuse to accept any application or may decide that the data are insufficient for approval and require additional preclinical studies, clinical trials or other studies and testing. In addition, the FDA and foreign regulatory authorities retain broad discretion in evaluating the results of our clinical trials and in determining whether the results demonstrate that selinexor or any of our other product candidates is safe and effective. If we are required to conduct additional clinical trials of selinexor or our other product candidates prior to approval of additional indications in earlier lines of therapy or in combination with other drugs, including additional earlier phase clinical trials that may be required prior to commencing any later phase clinical trials, or additional clinical trials following completion of our current and planned later phase clinical trials, we may need substantial additional funds, and there is no assurance that the results of any such additional clinical trials will be sufficient for approval.

The process of obtaining marketing approvals, both in the U.S. and abroad, is lengthy, expensive and uncertain. We have limited experience in conducting and managing the clinical trials necessary to obtain marketing approvals. The approval of our and our collaborators’ current or future product candidates for commercial sale could be delayed, limited or denied or we or they may be required to conduct additional studies for a number of reasons, including, but not limited to, the following:

Finally, disruptions at the FDA and other agencies may prolong the time necessary for new drugs to be reviewed and/or approved by necessary government agencies, which would adversely affect our business. For example, over the last several years, the U.S. government has shut down several times and certain regulatory agencies, such as the FDA, have had to furlough critical employees and stop critical activities. If a prolonged government shutdown occurs, it could significantly impact the ability of the FDA to timely review and process our regulatory submissions, which could have a material adverse effect on our business.

Any failure, delay or setback in obtaining regulatory approval for our or our collaborators’ product candidates could materially adversely affect our or our collaborators’ ability to generate revenue from a particular product candidate, which could result in significant harm to our financial position and adversely impact our stock price.

Serious adverse or unacceptable side effects related to XPOVIO or future products or product candidates may delay or prevent their regulatory approval, cause us or our collaborators to suspend or discontinue clinical trials, limit the commercial value of our approved indications or result in significant negative financial consequences following any marketing approval.

We currently have four product candidates in clinical development for the treatment of human diseases: selinexor, eltanexor, verdinexor and KPT-9274. Their risk of failure is high. If our current or future indications of XPOVIO or any of our product candidates are associated with undesirable side effects or have characteristics that are unexpected in clinical trials or following approval and/or commercialization, we may need to abandon or limit their development or limit marketing to certain uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective.

AEs in our clinical trials to date have been generally predictable and typically manageable, including through prophylactic care or dose reductions, although some patients have experienced more serious AEs. The most common drug-related AEs in our clinical trials for XPOVIO were fatigue, nausea, anorexia, diarrhea, peripheral neuropathy, upper respiratory tract infection, vomiting, cytopenias, hyponatremia, weight loss, decreased appetite, cataract, dizziness, syncope, depressed level of consciousness, and mental status changes. These side effects were generally mild or moderate in severity. The most common AEs that were Grade 3 or Grade 4, meaning they were more than mild or moderate in severity, included thrombocytopenia, lymphopenia, hypophosphatemia, anemia, hyponatremia and neutropenia. To date, the most common AEs in the multiple myeloma patient population have been managed with supportive care and dose modifications. However, a number of patients have withdrawn from our clinical trials as a result of AEs and some patients across our clinical trials have experienced serious AEs deemed by us and the clinical investigator to be related to selinexor. Serious AEs generally refer to AEs that result in death, are life threatening, require hospitalization or prolonging of hospitalization, or cause a significant and permanent disruption of normal life functions, congenital anomalies or birth defects, or require intervention to prevent such an outcome.

The occurrence of AEs in either our clinical trials or following regulatory approval could result in a more restrictive label for any product candidates approved for marketing or could result in the delay or denial of approval to market any product candidates by the FDA or comparable foreign regulatory authorities, which could prevent us from generating sufficient revenue from product sales or ultimately achieving profitability. Treatment-related side effects could also affect patient recruitment or the ability of enrolled patients to complete the trial, result in potential product liability claims or cause patients and/or healthcare providers to elect alternative courses of treatment. In addition, these side effects may not be appropriately recognized or managed by the treating medical staff. We engage in training programs for medical personnel using selinexor to help them understand and manage the side effect profiles for our clinical trials and following commercialization of any of our product candidates. Inadequate training in recognizing or managing the potential side effects of XPOVIO or our product candidates, if approved, could result in increased treatment-related side effects and cause patients to discontinue treatment. Any of these occurrences may harm our business, financial condition and prospects significantly.

Results of our trials could reveal an unacceptably high severity and prevalence of side effects. In such an event, our trials could be suspended or terminated and the FDA or comparable foreign regulatory authorities could order us or our collaborators to cease further development of or deny approval of our product candidates for any or all targeted indications. Many compounds that initially showed promise in early-stage trials for treating cancer or other diseases have later been found to cause side effects that prevented further development of the compound. If such an event occurs after any of our or our collaborators’ product candidates are approved and/or commercialized, a number of potentially significant negative consequences may result, including:

Further, we, our collaborators and our clinical trial investigators, currently determine if serious adverse or unacceptable side effects are drug-related. The FDA or foreign regulatory authorities may disagree with our, our collaborators’ or our clinical trial investigators’ interpretation of data from clinical trials and the conclusion by us, our collaborators or our clinical trial investigators that a serious adverse effect or unacceptable side effect was not drug-related. The FDA or foreign regulatory authorities may require more information related to the safety of our products or product candidates, including additional preclinical or clinical data to support approval, which may cause us to incur additional expenses, delay or prevent the approval of one of our product candidates, and/or delay or cause us to change our commercialization plans, or we may decide to abandon the development of the product candidate altogether.

Any of these events could prevent us or our collaborators from achieving or maintaining market acceptance of the affected product candidate, if approved, or could substantially increase costs and expenses of development or commercialization, which could delay or prevent us from generating sufficient revenue from the sale of our products and harm our business and results of operations.

The COVID-19 pandemic has adversely disrupted, and is expected to continue to adversely disrupt, our operations, including our clinical trial activities and commercial operations, which could have an adverse effect on our business and financial results.

As a result of the COVID-19 pandemic that has affected many segments of the global economy, we have experienced, and we expect to continue to experience, disruptions that could adversely impact our business, clinical trial activities and commercial operations, including:

The full extent of the impact of the disruptions to our business, including commercial sales and clinical trials, as a result of the pandemic will depend on the availability and effectiveness of vaccines and therapeutics and future developments, which are highly uncertain and cannot be predicted with confidence, such as the duration and severity of the pandemic, and the effectiveness of actions taken in the U.S. and other countries to contain and treat the disease. Due to the ongoing uncertainty regarding the severity and duration of the COVID-19 pandemic, we cannot predict whether our response to date or the actions we may take in the future will be effective in mitigating the effects of the COVID-19 pandemic on our business, results of operations or financial condition. Accordingly, we are unable at this time to predict the future impact of the COVID-19 pandemic on our operations, liquidity, and financial results.

The results of previous clinical trials may not be predictive of future trial results and interim or top-line data may be subject to change or qualification based on the complete analyses of data.

Clinical failure can occur at any stage of the clinical development process and, therefore, the outcome of preclinical studies and early-stage clinical trials may not be predictive of the success of later stage clinical trials. For example, certain data from our Phase 1 and Phase 2 clinical trials of selinexor are based on unaudited data provided by our clinical trial investigators. Finalization and cleaning of this data may change the conclusions drawn from this unaudited data provided by our clinical trial investigators indicating less promising results than we currently anticipate. Further, there can be significant variability in safety and/or efficacy results between different trials of the same product candidate due to numerous factors, including changes in trial protocols, differences in size and type of the patient populations, adherence to the dosing regimen and other trial protocols and the dropout rate among clinical trial participants. We do not know whether any Phase 2, Phase 3 or other clinical trials we may conduct will demonstrate consistent or adequate efficacy and safety data sufficient to obtain regulatory approval to market our product candidates, if approved. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies have suffered significant setbacks in late-stage clinical trials after achieving positive results in earlier development, and we could face similar setbacks.

We may publicly disclose preliminary, interim or top-line data from our clinical trials. These interim updates are based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change as further patient data become available and following a more comprehensive review of the data related to the particular study or trial. For example, in November 2020, we announced that our ongoing Phase 3 SIENDO study passed its planned interim futility analysis without the need to modify the study protocol or add additional patients. For this study or any other that we report preliminary, interim or top-line data, we make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. Consequently, the preliminary, interim or top-line data results that we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Preliminary, interim or top-line data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, these early data points should be viewed with caution until the final data are available.

Further, even if our product candidates achieve their primary endpoints in Phase 3 clinical trials or other registration trials, the FDA or foreign regulatory authorities may disagree with our trial design or our interpretation of data from preclinical studies and clinical trials. If the FDA, or other regulatory authorities, disagree about the overall benefit-risk assessment and data analyses, we may decide not to pursue regulatory approval or we may not obtain approval for our product candidates, which could harm our business, financial condition, results of operations and prospects.

We expect that in any later phase clinical trial where patients are randomized to receive either selinexor on the one hand, or standard of care, supportive care or placebo on the other hand, the primary endpoint will be either progression-free survival, meaning the length of time on treatment until objective tumor progression, or overall survival, while the primary endpoint in any later phase clinical trial that is not similarly randomized may be different. In some instances, the FDA and other regulatory bodies have accepted overall response rate as a surrogate for a clinical benefit and have granted regulatory approvals based on this or other surrogate endpoints, such as in our SADAL study and our STORM study. These clinical trials were not randomized against control arms and the primary endpoints of these trials were overall response rate. If selinexor does not demonstrate sufficient overall response rates for any other indication for which a clinical trial has overall response rate as a primary endpoint, or if the FDA or foreign regulatory authorities do not deem overall response rate a sufficient endpoint, or deem a positive overall response rate to be insufficient, selinexor will likely not be approved for that indication based on the applicable study.

Further, others, including regulatory agencies, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate or product and our company in general. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is typically selected from a more extensive amount of available information. Furthermore, we may report interim analyses of only certain endpoints rather than all endpoints. Investors may not agree with what we determine is the material or otherwise appropriate information to include in our disclosure, and any information we determine not to disclose may ultimately be deemed significant with respect to future decisions, conclusions, views, activities or otherwise regarding a particular product, product candidate or our business.

We may not be successful in our efforts to identify or discover additional potential product candidates or our decisions to prioritize the development of certain product candidates over others may later prove wrong.

Part of our strategy involves identifying and developing product candidates to build a pipeline of product candidates. Our drug discovery efforts may not be successful in identifying compounds that are useful in treating cancer or other diseases. Our research programs may initially show promise in identifying potential product candidates, yet fail to yield product candidates for clinical development for a number of reasons, including:

We are currently advancing multiple clinical development studies of selinexor and our other product candidates, which may create a strain on our limited human and financial resources. As a result, we may not be able to provide sufficient resources to any single product candidate to permit the successful development and commercialization of such product candidate, which could result in material harm to our business. Further, because we have limited financial and managerial resources, we focus on research programs and product candidates that we identify for specific indications. As a result, we may forego or delay pursuit of opportunities with other product candidates or for other indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development programs and product candidates for specific indications may not yield any additional commercially-viable products. If we do not accurately evaluate the commercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such product candidate.

If we are unable to maintain or expand our sales, marketing and distribution capabilities, we may not be successful in commercializing XPOVIO or any of our products or product candidates, if approved, that we may acquire or develop.

We have built a commercial infrastructure in the U.S. for XPOVIO, our first commercial product, in hematological malignancies and our company did not previously have any prior experience in the sales, marketing or distribution of pharmaceutical drugs. If XPOVIO or any of our other product candidates is approved for additional indications beyond hematological malignancies, such as solid tumors, we will need to substantially evolve our sales, marketing and distribution capabilities and we may not be able to do so successfully or on a timely basis. In the future, we may choose to expand our sales, marketing and distribution infrastructure to market or co-promote one or more of our product candidates, if and when they are approved, or enter into additional collaborations with respect to the sale, marketing and distribution of our product candidates. We intend to work with existing and potential partners to establish the commercial infrastructure to support a potential launch of selinexor outside of the U.S.

There are risks involved with establishing and maintaining our own sales, marketing and distribution capabilities. For example, recruiting and training a sales force is expensive and time-consuming and could delay any commercial launch of a product candidate. Further, we may underestimate the size of the sales force required for a successful product launch and we may need to expand our sales force earlier and at a higher cost than we anticipated. If the commercial launch of any of our product candidates is delayed or does not occur for any reason, including if we do not receive marketing approval in the timeframe we expect, we may have prematurely or unnecessarily incurred commercialization expenses. This may be costly, and our investment would be lost if we cannot retain or reposition our sales and marketing personnel.

Factors that may inhibit our efforts to successfully commercialize XPOVIO or any product candidates, if approved, on our own include:

Even if we or our collaborators are able to effectively commercialize XPOVIO or any approved product candidate that we may develop or acquire, the products may not receive coverage or may become subject to unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives, all of which would harm our business.

The legislation and regulations that govern marketing approvals, pricing and reimbursement for new drug products vary widely from country to country. As a result, we might obtain marketing approval for a drug in a particular country, but then be subject to price regulations that delay our commercial launch of the product, possibly for lengthy time periods, and negatively impact the revenues we or our collaborators are able to generate from product sales in that country. In the U.S., approval and reimbursement decisions are not linked directly, but there is increasing scrutiny from the Congress, regulatory authorities, payers, patients and pathway organizations of the pricing of pharmaceutical products. Adverse pricing limitations may also hinder our ability to recoup our investment in one or more product candidates, even if our product candidates obtain marketing approval.

Our ability to successfully commercialize XPOVIO or any of our product candidates that we may develop or acquire will depend, in part, on the extent to which reimbursement for these products is available from government health administration authorities, private health insurers and other organizations. Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which medications they will pay for and establish reimbursement levels. Obtaining and maintaining adequate reimbursement for XPOVIO and any of our product candidates, if approved, may be difficult. Moreover, the process for determining whether a third-party payor will provide coverage for a product may be separate from the process for setting the price of a product or for establishing the reimbursement rate that such a payor will pay for the product. Further, one payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage and reimbursement for our products by third-party payors. Even with payer coverage, patients may be unwilling or unable to pay the copay required and may choose not to take XPOVIO.

A primary trend in the healthcare industry in the U.S. and elsewhere is cost containment. Government authorities and third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. Increasingly, third-party payors are requiring that drug companies provide them with predetermined discounts from list prices and are challenging the prices charged for medical products. Third-party payors may also seek, with respect to an approved product, additional clinical evidence that goes beyond the data required to obtain marketing approval. They may require such evidence to demonstrate clinical benefits and value in specific patient populations or they may call for costly pharmaceutical studies to justify coverage and reimbursement or the level of reimbursement relative to other therapies before covering our products. Accordingly, we cannot be sure that reimbursement will be or will continue to be available for XPOVIO and any product that we commercialize and, if reimbursement is available, we cannot be sure as to the level of reimbursement and whether it will be adequate. Coverage and reimbursement may impact the demand for or the price of XPOVIO or any product candidate for which we obtain marketing approval. If reimbursement is not available or is available only at limited levels, we may not be able to successfully commercialize XPOVIO or any other approved products.

There may be significant delays in obtaining reimbursement for newly-approved drugs, and coverage may be more limited than the indications for which the drug is approved by the FDA or comparable foreign regulatory authorities. Moreover, eligibility for reimbursement does not imply that any drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim reimbursement levels for new drugs, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on reimbursement levels already set for lower cost drugs and may be incorporated into existing payments for other services. Net prices for drugs may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the U.S. Third-party payors often rely upon Medicare coverage policy and payment limitations in setting their own reimbursement policies. Our inability to promptly obtain coverage and profitable payment rates from both government-funded and private payors for any approved drugs that we develop could have a material adverse effect on our operating results, our ability to raise capital needed to commercialize our products and our overall financial condition.

Product liability lawsuits against us could divert our resources, cause us to incur substantial liabilities and limit commercialization of XPOVIO or any other products that we may develop or acquire.

We face an inherent risk of product liability exposure related to our commercialization of XPOVIO and the testing of our product candidates in human clinical trials as the administration of our products to humans may expose us to liability claims, whether or not our products are actually at fault for causing any harm or injury. As XPOVIO is used over longer periods of time by a wider group of patients taking numerous other medicines or by patients with additional underlying conditions, the likelihood of adverse drug reactions or unintended side effects, including death, may increase. For example, we may be sued if any drug we develop allegedly causes injury or is found to be otherwise unsuitable during clinical testing, manufacturing, marketing or sale. Any such product liability claims may include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability or a breach of warranties. Claims could also be asserted under state consumer protection acts. If we cannot successfully defend ourselves against claims that our products or product candidates caused injuries, we will incur substantial liabilities or be required to limit commercialization of our products. Regardless of merit or eventual outcome, liability claims may result in:

We currently hold clinical trial and general product liability insurance coverage, but that coverage may not be adequate to cover any and all liabilities that we may incur. Insurance coverage is increasingly expensive. We may not be able to maintain insurance coverage at a reasonable cost or in an amount adequate to satisfy any liability that may arise.

The business that we conduct outside of the U.S. may be adversely affected by international risks and uncertainties.

Although our operations are primarily based in the U.S., we conduct business outside of the U.S. and expect to continue to do so in the future. For instance, many of the sites at which our clinical trials are being conducted are located outside of the U.S. In addition, we and our collaborators are seeking and continue to plan to seek approvals to sell our and their products in foreign countries. Any business that we or our collaborators conduct outside of the U.S. will be subject to additional risks that may materially adversely affect our or their ability to conduct business in international markets, including:

We may seek approval from the FDA or comparable foreign regulatory authorities to use accelerated development pathways for our product candidates. If we are not able to use such pathways, we may be required to conduct additional clinical trials beyond those that we contemplate, which would increase the expense of obtaining, and delay the receipt of, necessary marketing approvals, if we receive them at all. In addition, even if an accelerated approval pathway is available to us, it may not lead to expedited approval of our product candidates, or approval at all.

Under the Federal Food, Drug and Cosmetic Act (“FDCA”) and implementing regulations, the FDA may grant accelerated approval to a product candidate to treat a serious or life-threatening condition that provides meaningful therapeutic benefit over available therapies, upon a determination that the product has an effect on a surrogate endpoint or intermediate clinical endpoint that is reasonably likely to predict clinical benefit. The FDA considers a clinical benefit to be a positive therapeutic effect that is clinically meaningful in the context of a given disease, such as irreversible morbidity or mortality. For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. An intermediate clinical endpoint is a clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit measurement of a therapeutic effect that is considered reasonably likely to predict the clinical benefit of a drug. The accelerated approval pathway may be used in cases in which the advantage of a new drug over available therapy may not be a direct therapeutic advantage, but is a clinically important improvement from a patient and public health perspective. Prior to seeking such accelerated approval, we will continue to seek feedback from the FDA or comparable foreign regulatory agencies and otherwise evaluate our ability to seek and receive such accelerated approval.

There can be no assurance that the FDA or foreign regulation agencies will agree with our surrogate endpoints or intermediate clinical endpoints in any of our clinical trials, or that we will decide to pursue or submit any additional New Drug Applications (“NDA”) for accelerated approval or any other form of expedited development, review or approval. Similarly, there can be no assurance that, after feedback from the FDA or comparable foreign regulatory agencies, we will continue to pursue or apply for accelerated approval or any other form of expedited development, review or approval. Furthermore, for any submission of an application for accelerated approval or application under another expedited regulatory designation, there can be no assurance that such submission or application will be accepted for filing or that any expedited development, review or approval will be granted on a timely basis, or at all.

A failure to obtain accelerated approval or any other form of expedited development, review or approval for our product candidates, or withdrawal of a product candidate, would result in a longer time period until commercialization of such product candidate, could increase the cost of development of such product candidate and could harm our competitive position in the marketplace.

Under accelerated or conditional approval regulations of the FDA or comparable foreign regulatory authorities, we must comply with post-approval development and regulatory requirements to maintain our approval of XPOVIO or any future approved products and, if we fail to do so, the FDA or comparable foreign regulatory authorities could withdraw its approval of XPOVIO or any future approved products for the indication that received accelerated or conditional approval, which would lead to substantially lower revenues.

For drugs approved under the FDA’s Accelerated Approval Program, the FDA typically requires post-marketing confirmatory trials to evaluate the anticipated effect on irreversible morbidity or mortality or other clinical benefit. These confirmatory trials must be completed with due diligence. For example, in June 2020, the FDA approved XPOVIO to treat DLBCL under the FDA’s accelerated approval regulations and as a condition of the accelerated approval for this indication we are required to (i) complete and submit a final report with full datasets from a randomized, double-blind, placebo-controlled Phase 3 trial that verifies and describes the clinical benefit of selinexor in patients with relapsed or refractory DLBCL and (ii) provide the interim and final analyses of a randomized Phase 2 clinical trial of selinexor to characterize the safety and efficacy of at least two different dosing regimens of selinexor monotherapy in patients with relapsed or refractory DLBCL after at least two prior lines of systemic therapy. We intend to satisfy the Phase 3 trial requirement though our ~~recently initiated~~ XPORT-DLBCL-030 study and we may not be able to successfully and timely complete this study or any other post-marketing confirmatory study as required to maintain approval or achieve full approval, including as a result of adverse impacts from the ongoing COVID-19 pandemic. If the required post-approval studies fail to verify the clinical benefits of XPOVIO or confirm that the surrogate marker used for accelerated approval of XPOVIO to treat DLBCL showed an adequate correlation with clinical outcomes, if a sufficient number of participants cannot be enrolled, or if we fail to perform the required post-approval studies with due diligence or on a timely basis, the FDA has the authority to withdraw approval of the drug following a hearing conducted under the FDA’s regulations, which would have a material adverse impact on our business. We cannot be certain of the results of the confirmatory clinical studies for the DLBCL indication or any other future conditional approval we receive or what action the FDA may take if the results of those studies are not as expected based on clinical data that FDA has already reviewed.

Similar risks to those described above are also applicable to any application that we have submitted or may submit to the EMA to support conditional approval of selinexor to treat heavily pretreated multiple myeloma, relapsed or refractory DLBCL, or any other cancer indication. For medicinal products where the benefit of immediate availability outweighs the risk of less comprehensive data than normally required, based on the scope and criteria defined in legislation and guidelines, it is possible to obtain a conditional marketing authorization in the European Union (the “EU”) with a 12 month validity period and annual renewal pursuant to Regulation No 507/2006. These are granted only if the EMA’s Committee for Medicinal Products for Human Use finds that all four requirements are met: (i) the benefit-risk balance of the product is positive; (ii) it is likely that the applicant will be able to provide comprehensive data; (iii) unmet medical needs will be fulfilled; and (iv) the benefit to public health of the medicinal product’s immediate availability on the market outweighs the risks due to need for further data. Once a conditional marketing authorization has been granted, the marketing authorization holder must fulfil specific obligations within defined timelines. These obligations could include completing ongoing or new studies or collecting additional data to confirm the medicine’s benefit-risk balance remains positive.

In March 2021, we received conditional marketing authorization from the European Commission for NEXPOVIO to treat adult patients with multiple myeloma who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, two immunomodulatory agents, and an anti-CD38 monoclonal antibody, and who have demonstrated disease progression on the last therapy. This marketing authorization, or any others we obtain from the European Commission in the future, is valid for a period for one year and could be renewed/prolonged if the conditions set out in the conditional marketing authorization are met. If we are not able to fulfill these specific obligations set out in the conditional marketing authorization requirements (which include the presentation of additional clinical data on the safety and efficacy for NEXPOVIO), the marketing authorization for the EU may not be prolonged and we will no longer be able to market NEXPOVIO in the EU.

XPOVIO and any of our product candidates for which we or our collaborators obtain marketing approval in the future could be subject to post-marketing restrictions or withdrawal from the market, and we and our collaborators may be subject to substantial penalties if we, or they, fail to comply with regulatory requirements or if we, or they, experience unanticipated problems with our products following approval.

XPOVIO and any of our product candidates for which we or our collaborators obtain marketing approval in the future, as well as the manufacturing processes, post-approval studies and measures, labeling, advertising and promotional activities for such drug, among other things, will be subject to continual requirements of and review by the FDA and other regulatory authorities. These requirements include submissions of safety and other post-marketing information and reports, registration and listing requirements, requirements relating to manufacturing, quality control, quality assurance and corresponding maintenance of records and documents, and requirements regarding the distribution of samples to physicians and recordkeeping. For example, as a condition of the XPOVIO approval for the multiple myeloma and DLBCL indications, we are required to complete certain post-marketing commitments. Even if marketing approval of a product candidate is granted, the approval may be subject to limitations on the indicated uses for which the drug may be marketed or to the conditions of approval, including the requirement to implement a Risk Evaluation and Mitigation Strategy, which could include requirements for a restricted distribution system.

The FDA may also impose requirements for costly post-marketing studies or clinical trials and surveillance to monitor the safety or efficacy of a drug. The FDA and other agencies, including the Department of Justice (the “DOJ”) closely regulate and monitor the post-approval marketing and promotion of drugs to ensure that they are manufactured, marketed and distributed only for the approved indications and in accordance with the provisions of the approved labeling. The FDA imposes stringent restrictions on manufacturers’ communications regarding off-label use, and if we or our collaborators do not market any of our product candidates for which we, or they, receive marketing approval for only their approved indications, we, or they, may be subject to warnings or enforcement action for off-label marketing. Violation of the FDCA and other statutes, including the False Claims Act (the “FCA”), relating to the promotion and advertising of prescription drugs may lead to investigations or allegations of violations of federal and state health care fraud and abuse laws and state consumer protection laws. In addition, later discovery of previously unknown AEs or other problems with our products or their manufacturers or manufacturing processes, data integrity issues with regulatory filings, or failure to comply with regulatory requirements, may yield various results, including:

Similar restrictions apply to the approval of our products in the EU. The holder of the marketing authorization is required to comply with a range of requirements applicable to the manufacturing, marketing, promotion and sale of medicinal products. These include:

If we or our collaborators do not comply with these and other applicable requirements, we or they may face enforcement actions by the European regulatory authorities that adversely affect our or their ability to market products in Europe and would have a material impact on our business.

Our or our collaborators’ failure to obtain marketing approval in foreign jurisdictions would prevent our or their product candidates from being marketed abroad, and any approval we are granted for product candidates in the U.S. does not assure approval of product candidates in foreign jurisdictions.

In order to market and sell our products in the EU and many other jurisdictions, we and our current or future collaborators must obtain separate marketing approvals and comply with numerous and varying regulatory requirements. The approval procedure varies among countries and can involve additional testing. The time required to obtain approval outside of the U.S. may differ substantially from that required to obtain FDA approval. The marketing approval process outside of the U.S. generally includes at least all of the risks associated with obtaining FDA approval. In addition, in many countries outside of the U.S., it is required that the drug be approved for reimbursement before the drug can be approved for sale in that country. We and our collaborators may not obtain approvals from regulatory authorities outside of the U.S. on a timely basis, if at all. Approval by the FDA does not ensure approval by regulatory authorities in other countries or jurisdictions, and approval by one regulatory authority outside of the U.S. does not ensure approval by regulatory authorities in other countries or jurisdictions or by the FDA. However, a failure or delay in obtaining regulatory approval in one country may have a negative effect on the regulatory process in other countries. We or our collaborators may not be able to file for marketing approvals and may not receive necessary approvals to commercialize our or their products in any market.

In June 2016, the electorate in the United Kingdom (“UK”) voted in favor of leaving the EU, commonly referred to as “Brexit”. Following protracted negotiations, the UK left the EU on January 31, 2020 and the EU rules and regulations ceased to apply to the UK starting on January 1, 2021. In December 2020, the UK government and the EU agreed on a long-term trade agreement to govern economic relations going forward. Since the existing regulatory framework for pharmaceutical products in the UK is derived from EU directives and regulations, Brexit could materially impact the future regulatory regime for pharmaceutical products in the UK, which remains uncertain. We and our collaborators are continuing to analyze how Brexit and the recently concluded trade agreement will affect the future regulatory regime for pharmaceutical products in the UK. Any delay in obtaining, or an inability to obtain, any marketing approvals, as a result of Brexit or otherwise, would prevent us or our collaborators from commercializing our product

candidates in the UK and/or the EU and restrict our ability to generate revenue and achieve and sustain profitability. If any of these outcomes occur, we or our collaborators may be forced to restrict or delay efforts to seek regulatory approval in the UK and/or EU for our product candidates, which could significantly and materially harm our business.

Further, we expect that we or our collaborators will be subject to additional risks in commercializing any of our product candidates that receive marketing approval outside the U.S., including tariffs, trade barriers and regulatory requirements; economic weakness, including inflation, or political instability in particular foreign economies and markets; compliance with tax, employment, immigration and labor laws for employees living or traveling abroad; foreign currency fluctuations, which could result in increased operating expenses and reduced revenue, and other obligations incident to doing business in another country; and workforce uncertainty in countries where labor unrest is more common than in the U.S.

We may seek certain designations for our product candidates, including Breakthrough Therapy, Fast Track and Priority Review designations, but we might not receive such designations, and even if we do, such designations may not lead to a faster development or regulatory review or approval process.

We may seek certain designations for one or more of our product candidates that could expedite review and approval by the FDA. A Breakthrough Therapy product is defined as a product that is intended, alone or in combination with one or more other products, to treat a serious condition, and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. For products that have been designated as breakthrough therapies, interaction and communication between the FDA and the sponsor of the trial can help to identify the most efficient path for clinical development while minimizing the number of patients placed in ineffective control regimens.

The FDA may also designate a product for Fast Track review if it is intended, whether alone or in combination with one or more other products, for the treatment of a serious or life-threatening disease or condition, and it demonstrates the potential to address unmet medical needs for such a disease or condition. For Fast Track products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a Fast Track product’s application before the application is complete. This rolling review may be available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a Fast Track product may be effective.

We may also seek a priority review designation for one or more of our product candidates. If the FDA determines that a product candidate offers major advances in treatment or provides a treatment where no adequate therapy exists, the FDA may designate the product candidate for priority review. A priority review designation means that the goal for the FDA to review an application is six months, rather than the standard review period of ten months.

These designations are within the discretion of the FDA. Accordingly, even if we believe that one of our product candidates meets the criteria for these designations, the FDA may disagree and instead determine not to make such designation. Further, even if we receive a designation, the receipt of such designation for a product candidate may not result in a faster development or regulatory review or approval process compared to products considered for approval under conventional FDA procedures and does not assure ultimate approval by the FDA. For example, in connection with our NDA for XPOVIO, in March 2019, the FDA extended the Prescription Drug User Fee Act action date by three months following our submission of additional, existing clinical information as an amendment to the NDA, which resulted in a nine-month review cycle despite the priority review designation. In addition, even if one or more of our product candidates qualifies for these designations, the FDA may later decide that the product candidates no longer meet the conditions for qualification or decide that the time period for FDA review or approval will not be shortened.

We may not be able to obtain orphan drug exclusivity for our product candidates.

Regulatory authorities in some jurisdictions, including the U.S. and Europe, may designate drugs and biologics for relatively small patient populations as orphan drugs. Under the Orphan Drug Act, the FDA may designate a product as an orphan drug if it is a drug or biologic intended to treat a rare disease or condition, which is generally defined as a patient population of fewer than 200,000 individuals annually in the U.S.

Generally, if a product with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a period of marketing exclusivity, which precludes the EMA or the FDA from approving another marketing application for the same product for that time period. The applicable period is seven years in the U.S. and ten years in Europe. The European exclusivity period can be reduced to six years if a product no longer meets the criteria for orphan drug designation or if the product is sufficiently profitable so that market exclusivity is no longer justified. Orphan drug exclusivity may be lost if the FDA or EMA determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantity of the product to meet the needs of patients with the rare disease or condition.

Even if we obtain orphan drug exclusivity from the FDA for a product, as we have for XPOVIO as a treatment for patients with heavily pretreated multiple myeloma and DLBCL and selinexor in acute myeloid leukemia, that exclusivity may not effectively protect the product from competition because different products can be approved for the same condition. Even after an orphan drug is approved, the FDA can subsequently approve a different product for the same condition if the FDA concludes that the later product is clinically superior in that it is shown to be safer, more effective or makes a major contribution to patient care.

Even if we or any of our collaborators obtain marketing approvals for our product candidates, the terms of approvals and ongoing regulation of our products may limit how we, or they, manufacture and market our products, which could materially impair our ability to generate revenue.

Once marketing approval has been granted, an approved product and its manufacturer and marketer are subject to ongoing review and extensive regulation. We and our collaborators must therefore comply with requirements concerning advertising and promotion for XPOVIO or for any of our or their approved products. Promotional communications with respect to prescription drugs are subject to a variety of legal and regulatory restrictions and must be consistent with the information in the drug’s approved labeling. Thus, we and our collaborators may not be able to promote any product we develop for indications or uses for which they are not approved.

In addition, manufacturers of approved products and those manufacturers’ facilities are required to comply with extensive FDA requirements, including ensuring that quality control and manufacturing procedures conform to cGMPs, which include requirements relating to quality control and quality assurance as well as the corresponding maintenance of records and documentation and reporting requirements. We, our contract manufacturers, our collaborators and their contract manufacturers could be subject to periodic unannounced inspections by the FDA or foreign regulatory authorities to monitor and ensure compliance with cGMPs or other regulations.

Accordingly, in connection with our currently approved products and assuming we or our current or future collaborators receive marketing approval for one or more of our product candidates, we, and our collaborators, and our and their contract manufacturers will continue to expend time, money and effort in all areas of regulatory compliance, including manufacturing, production, product surveillance and quality control. If we and our collaborators are not able to comply with post-approval regulatory requirements, regulatory authorities could withdraw the marketing approvals of our products, and our or our collaborators’ ability to market any future products could be limited, which could adversely affect our ability to achieve or sustain profitability. Further, the cost of compliance with post-approval regulations may have a negative effect on our operating results and financial condition.

Current and future legislation may increase the difficulty and cost for us and any collaborators to obtain marketing approval and commercialize our or their product candidates and affect the prices we, or they, may obtain.

In the U.S. and some foreign jurisdictions, there have been a number of legislative and regulatory changes and proposed changes regarding the healthcare system that could, among other things, prevent or delay marketing approval of our or our collaborators’ product candidates, restrict or regulate post-approval activities and affect our ability, or the ability of any collaborators, to profitably sell or commercialize XPOVIO or any product candidate for which we, or they, obtain marketing approval. We expect that current laws, as well as other healthcare reform measures that may be adopted in the future, may result in more rigorous coverage criteria and in additional downward pressure on the price that we, or any collaborators, may receive for any approved products. If reimbursement of our products is unavailable or limited in scope, our business could be materially harmed.

In March 2010, President Obama signed into law the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Affordability Reconciliation Act (collectively the “ACA”). In addition, other legislative changes have been proposed and adopted since the ACA was enacted. In August 2011, the Budget Control Act of 2011, among other things, created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the years 2013 through 2021, was unable to reach required goals, thereby triggering the legislation’s automatic reduction to several government programs. These changes included aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, which went into effect in April 2013 and will remain in effect through 2030 under the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”). The American Taxpayer Relief Act of 2012, among other things, reduced Medicare payments to several providers and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. These laws may result in additional reductions in Medicare and other healthcare funding and otherwise affect the prices we may obtain for any of our products or product candidates for which we may obtain regulatory approval or the frequency with which any such product is prescribed or used.

Since enactment of the ACA, there have been, and continue to be, numerous legal challenges and Congressional actions to repeal and replace provisions of the law. For example, with enactment of the Tax Cuts and Jobs Act of 2017, which was signed by President Trump on December 22, 2017, Congress repealed the “individual mandate.” The repeal of this provision, which requires

most Americans to carry a minimal level of health insurance, became effective in 2019. Further, on December 14, 2018, a U.S. District Court judge in the Northern District of Texas ruled that the individual mandate portion of the ACA is an essential and inseverable feature of the ACA, and therefore because the mandate was repealed as part of the Tax Cuts and Jobs Act, the remaining provisions of the ACA are invalid as well. On December 18, 2019, the Court of Appeals for the Fifth Circuit court affirmed the lower court’s ruling that the individual mandate portion of the ACA is unconstitutional and it remanded the case to the district court for reconsideration of the severability question and additional analysis of the provisions of the ACA. Thereafter, the U.S. Supreme Court agreed to hear this case. Oral argument in the case took place on November 10, ~~2020, and a ruling by~~2020. On June 17, 2021, the Court ~~is expected sometime this year.~~reversed and remanded the Appeals Court ruling, finding that the plaintiffs did not have standing to challenge the ACA. Litigation and legislation over the ACA are likely to continue, with unpredictable and uncertain results.

The Trump Administration also took executive actions to undermine or delay implementation of the ACA, including directing federal agencies with authorities and responsibilities under the ACA to waive, defer, grant exemptions from, or delay the implementation of any provision of the ACA that would impose a fiscal or regulatory burden on states, individuals, healthcare providers, health insurers, or manufacturers of pharmaceuticals or medical devices. On January 28, 2021, however, President Biden issued a new Executive Order which directs federal agencies to reconsider rules and other policies that limit Americans’ access to health care, and consider actions that will protect and strengthen that access. Under this Order, federal agencies are directed to re-examine: policies that undermine protections for people with pre-existing conditions, including complications related to COVID-19; demonstrations and waivers under Medicaid and the ACA that may reduce coverage or undermine the programs, including work requirements; policies that undermine the health insurance marketplace or other markets for health insurance; policies that make it more difficult to enroll in Medicaid and the ACA; and policies that reduce affordability of coverage or financial assistance, including for dependents.

We expect that these healthcare reforms, as well as other healthcare reform measures that may be adopted in the future, may result in additional reductions in Medicare and other healthcare funding, more rigorous coverage criteria and new payment methodologies that govern XPOVIO or any other approved product and/or the level of reimbursement physicians receive for administering XPOVIO or any other approved product we might bring to market. Reductions in reimbursement levels may negatively impact the prices we receive or the frequency with which our products are prescribed or administered. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors. Accordingly, such reforms, if enacted, could have an adverse effect on anticipated revenue from XPOVIO or from product candidates for which we may obtain marketing approval and may affect our overall financial condition and ability to develop or commercialize product candidates.

Further, outside of the US, including the countries of the EU, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a drug. To obtain reimbursement or pricing approval in some countries, we or our existing and future collaborators may be required to conduct a clinical trial that compares the cost-effectiveness of our products to other available therapies. If reimbursement of our products is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, our business could be materially harmed.

Current and future legislative efforts may limit the costs for our products, if and when they are approved for marketing, and that could materially impact our ability to generate revenues.

The containment of healthcare costs has become a priority of federal, state and foreign governments and the prices of pharmaceutical products have been a focus in this effort. Governments have shown significant interest in implementing cost-containment programs, including rebate programs, price controls, restrictions on reimbursement and requirements for substitution of generic products. Controlling drug pricing has garnered bipartisan support in U.S. Congress. To that end, the Trump Administration published final rules that would allow states or certain other non-federal government entities to submit importation program proposals to the FDA for review and approval. Applicants would be required to demonstrate that their importation plans pose no additional risk to public health and safety and will result in significant cost savings for consumers. Earlier, the FDA had issued draft guidance that would allow manufacturers to import their own FDA-approved drugs that are authorized for sale in other countries (multi-market approved products). Further, President Trump issued five executive orders intended to lower the costs of prescription drug products. Several of these orders are reflected in recently promulgated regulations, and one of these regulations is currently subject to a nationwide preliminary injunction.

The Biden Administration has frozen certain of the previous administration’s measures to reform drug prices, pending further review. It remains to be seen how the Biden Administration will address this issue but, under Medicare Part D, the new administration may seek to establish a ceiling for the launch prices of all branded, biologic, and certain generic drugs by referencing the average price of these drugs in other developed countries. At the same time, the administration may seek to limit Medicare Part D and public option drug prices through a tax penalty on manufacturers for increases in the cost of drugs and biologics above the general inflation rate.

The Biden administration has agreed to delay for a year the implementation of one of President Trump’s signature drug pricing

policies, from January 2022 to 2023. The policy at issue would have prevented drug makers and middlemen from negotiating rebates on prescription drugs.

At the state level, legislatures are increasingly passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In addition, regional health care authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products and which suppliers will be included in their prescription drug and other health care programs. These measures could reduce the ultimate demand for our approved products or put pressure on our product pricing. We expect that additional state and federal healthcare reform measures will be adopted in the future, any of which could limit the amounts that federal and state governments will pay for healthcare products and services, which could result in reduced demand for our products or additional pricing pressures.

Finally, outside the U.S., in some nations, including those of the EU, the pricing of prescription pharmaceuticals is subject to governmental control and access. In these countries, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we or our collaborators may be required to conduct a clinical trial that compares the cost-effectiveness of our product to other available therapies.

These measures, as well as others adopted in the future, may result in additional downward pressure on the price that we receive for XPOVIO or any other approved product we might bring to market. Accordingly, such reforms, if enacted, could have an adverse effect on anticipated revenue from XPOVIO or from product candidates that we may successfully develop and for which we may obtain marketing approval and may affect our overall financial condition and ability to develop or commercialize product candidates.

Our reporting and payment obligations under the Medicaid Drug Rebate Program and other governmental drug pricing programs are complex and may involve subjective decisions. Any failure to comply with those obligations could subject us to penalties and sanctions.

As a condition of reimbursement by various federal and state health insurance programs, we are required to calculate and report certain pricing information to federal and state agencies. The regulations governing the calculations, price reporting and payment obligations are complex and subject to interpretation by various government and regulatory agencies, as well as the courts. Reasonable assumptions have been made where there is lack of regulations or clear guidance and such assumptions involve subjective decisions and estimates. We are required to report any revisions to our calculation, price reporting and payment obligations previously reported or paid. Such revisions could affect our liability to federal and state payers and also adversely impact our reported financial results of operations in the period of such restatement.

Uncertainty exists as new laws, regulations, judicial decisions, or new interpretations of existing laws, or regulations related to our calculations, price reporting or payments obligations increases the chances of a legal challenge, restatement or investigation. If we become subject to investigations, restatements, or other inquiries concerning our compliance with price reporting laws and regulations, we could be required to pay or be subject to additional reimbursements, penalties, sanctions or fines, which could have a material adverse effect on our business, financial condition and results of operations. In addition, it is possible that future healthcare reform measures could be adopted, which could result in increased pressure on pricing and reimbursement of our products and thus have an adverse impact on our financial position or business operations.

Further, state Medicaid programs may be slow to invoice pharmaceutical companies for calculated rebates resulting in a lag between the time a sale is recorded and the time the rebate is paid. This results in us having to carry a liability on our consolidated balance sheets for the estimate of rebate claims expected for Medicaid patients. If actual claims are higher than current estimates, our financial position and results of operations could be adversely affected.

In addition to retroactive rebates and the potential for 340B Program refunds, if we are found to have knowingly submitted any false price information related to the Medicaid Drug Rebate Program to the Centers for Medicare & Medicaid Services (“CMS”), we may be liable for civil monetary penalties. Such failure could also be grounds for CMS to terminate our Medicaid drug rebate agreement, pursuant to which we participate in the Medicaid program. In the event that CMS terminates our rebate agreement, federal payments may not be available under government programs, including Medicaid or Medicare Part B, for our covered outpatient drugs.

Additionally, if we overcharge the government in connection with the FSS program or Tricare Retail Pharmacy Program, whether due to a misstated Federal Ceiling Price or otherwise, we are required to refund the difference to the government. Failure to make necessary disclosures and/or to identify contract overcharges can result in allegations against us under the FCA and other laws

and regulations. Unexpected refunds to the government, and responding to a government investigation or enforcement action, would

be expensive and time-consuming, and could have a material adverse effect on our business, financial condition, results of operations and growth prospects.

Our collaborators are also subject to similar requirements and thus the attendant risks and uncertainties. If our collaborators suffer material and adverse effects from such risks and uncertainties, our rights and benefits for our licensed products could be negatively impacted, which could have a material and adverse impact on our revenues.

Our relationships with healthcare providers and physicians and third-party payors are subject to applicable anti-kickback, fraud and abuse and other healthcare laws and regulations, which could expose us to criminal sanctions, civil penalties, contractual damages, reputational harm and diminished profits and future earnings.

Healthcare providers, physicians and third-party payors play a primary role in the recommendation and prescription of our approved products. Our arrangements with third-party payors, healthcare providers and physicians may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we market, sell and distribute any approved product. These include the Federal Anti-Kickback Statute, the FCA and federal transparency requirements (and their state analogues), as discussed ~~above~~ in Item 1 under the heading “Healthcare Law and Regulation” in ~~this~~our Annual ~~Report on Form 10-K.~~Report.

Some state laws require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government and require drug manufacturers to report information related to payments and other transfers of value to physicians and other healthcare providers or marketing expenditures. State and foreign laws also govern the privacy and security of health information in some circumstances, many of which differ from each other in significant ways and often are not pre-empted by the Health Insurance Portability and Accountability Act of 1996 (“HIPAA”), as amended by the Health Information Technology for Economic and Clinical Health Act of 2009 (“HITECH”), thus complicating compliance efforts.

Efforts to ensure that our business arrangements with third parties will comply with applicable healthcare laws and regulations involve substantial costs. It is possible that governmental authorities will conclude that our business practices may not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations are found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, imprisonment, exclusion of drugs from government funded healthcare programs, such as Medicare and Medicaid, and the curtailment or restructuring of our operations. If any of the physicians or other healthcare providers or entities with whom we do business is found to be not in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs.

The provision of benefits or advantages to physicians to induce or encourage the prescription, recommendation, endorsement, purchase, supply, order or use of medicinal products is also prohibited in the EU. The provision of benefits or advantages to physicians is governed by the national anti-bribery laws of EU Member States. Infringement of these laws could result in substantial fines and imprisonment.

Payments made to physicians in certain EU Member States must be publicly disclosed. Moreover, agreements with physicians often must be the subject of prior notification and approval by the physician’s employer, his or her competent professional organization and/or the regulatory authorities of the individual EU Member States. These requirements are provided in the national laws, industry codes or professional codes of conduct, applicable in the EU Member States. Failure to comply with these requirements could result in reputational risk, public reprimands, administrative penalties, fines or imprisonment.

Compliance with global privacy and data security requirements could result in additional costs and liabilities to us or inhibit our ability to collect and process data globally, and the failure to comply with such requirements could subject us to significant fines and penalties, which may have a material adverse effect on our business, financial condition or results of operations.

We are subject to a significant number of privacy and data protection laws and regulations globally, many of which place restrictions on our ability to transfer, access and use personal data across our business. The legislative and regulatory landscape for privacy and data protection is rapidly evolving and is likely to remain uncertain for the foreseeable future. Globally, virtually every jurisdiction in which we operate has established its own data security and privacy frameworks with which we must comply, with additional laws and amendments being passed on a regular basis. For example, the EU General Data Protection Regulation (the “GDPR”) imposes strict requirements on data controllers and processors of personal data, including personal health data, and penalties for noncompliance may include fines of up to four percent of a company’s global annual revenue. The GDPR increases our obligations with respect to clinical trials conducted in the European Economic Area (“EEA”) by expanding the definition of personal

data to include coded data and requiring changes to informed consent practices and more detailed notices for clinical trial subjects and

investigators. In addition, the GDPR also imposes strict rules on the transfer of personal data to countries outside of the EU, including the U.S. and, as a result, increases the scrutiny that clinical trial sites located in the EEA should apply to transfers of personal data from such sites to countries that are considered to lack an adequate level of data protection, such as the U.S.

In the U.S., there are a broad variety of data protection laws that are applicable to our activities, and a wide range of enforcement agencies at both the state and federal levels that can review companies for privacy and data security concerns based on general consumer protection laws. For example, the California Consumer Privacy Act (the “CCPA”), which went into effect on January 1, 2020, creates similar risks and obligations as those created by GDPR, though the CCPA does exempt certain information collected as part of a clinical trial subject to the Federal Policy for the Protection of Human Subjects (the “Common Rule”). The California Privacy Rights Act, which took effect on January 1, 2021, significantly expands the CCPA. Many other states are considering similar legislation and a broad range of legislative measures also have been introduced at the federal level. In addition, the Federal Trade Commission and state Attorneys General all are aggressive in reviewing privacy and data security protections for consumers.

Any inability to comply with applicable laws, regulations, policies, industry standards or other legal obligations regarding data protection or privacy either in the U.S. or in other jurisdictions where we do business could result in the imposition of fines, penalties, orders to stop non-compliant activities, or other liabilities, and could harm our reputation and our business.

Our employees, independent contractors, consultants and vendors may engage in misconduct or other improper activities, including non-compliance with regulatory standards and requirements and insider trading, which could cause significant liability for us and harm our reputation.

We are exposed to the risk of fraud or other misconduct by our employees, independent contractors, consultants and vendors. Misconduct by these partners could include intentional failures to comply with FDA regulations or similar regulations of comparable foreign regulatory authorities, provide accurate information to the FDA or comparable foreign regulatory authorities, comply with manufacturing standards, comply with federal and state healthcare fraud and abuse laws and regulations and similar laws and regulations established and enforced by comparable foreign regulatory authorities, report financial information or data accurately or disclose unauthorized activities to us. Employee misconduct could also involve the improper use of information obtained in the course of clinical trials, which could result in regulatory sanctions and serious harm to our reputation. This could include violations of HIPAA, other U.S. federal and state ~~law,~~laws, and requirements of foreign jurisdictions, including the GDPR. We are also exposed to risks in connection with any insider trading violations by employees or others affiliated with us. It is not always possible to identify and deter employee misconduct, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to be in compliance with such laws, standards, regulations, guidance or codes of conduct. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business and results of operations, including the imposition of significant fines or other sanctions.

If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could have a material adverse effect on our business.

We are subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Our operations involve the use of hazardous and flammable materials, including chemicals and biological and radioactive materials. Our operations also produce hazardous waste products. We generally contract with third parties for the disposal of these materials and wastes. We cannot eliminate the risk of contamination or injury from these materials. In the event of contamination or injury resulting from our use of hazardous materials, we could be held liable for any resulting damages, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties.

Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials, this insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological, hazardous or radioactive materials.

In addition, we may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research, development or commercialization efforts. Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

Laws and regulations governing any international operations we may have in the future may preclude us from developing, manufacturing and selling certain products outside of the U.S. and require us to develop and implement costly compliance programs.

We are subject to numerous laws and regulations in each jurisdiction outside of the U.S. in which we operate. The creation, implementation and maintenance of international business practices compliance programs is costly and such programs are difficult to enforce, particularly where reliance on third parties is required.

The FCPA prohibits any U.S. individual or business from paying, offering, authorizing payment or offering of anything of value, directly or indirectly, to any foreign official, political party or candidate for the purpose of influencing any act or decision of the foreign entity in order to assist the individual or business in obtaining or retaining business. The FCPA also obligates companies whose securities are listed in the U.S. to comply with certain accounting provisions requiring us to maintain books and records that accurately and fairly reflect all transactions of the corporation, including international subsidiaries, and to devise and maintain an adequate system of internal accounting controls. The FCPA is enforced by the DOJ and the SEC.

Compliance with the FCPA is expensive and difficult, particularly in countries in which corruption is a recognized problem. In addition, the FCPA presents particular challenges in the pharmaceutical industry, because, in many countries, hospitals, clinics, universities and similar institutions are operated by the government, and doctors and other healthcare professionals are considered foreign officials. Certain payments to healthcare professionals in connection with clinical trials, regulatory approvals, sales and marketing, and other work have been deemed to be improper payments to government officials and have led to FCPA enforcement actions. Because the FCPA applies to indirect payments, the use of third parties and other collaborators can increase potential FCPA risk, as we could be held liable for the acts of third parties that do not comply with the FCPA’s requirements.

The failure to comply with laws governing international business practices may result in substantial penalties, including suspension or debarment from government contracting. Violation of the FCPA can result in significant civil and criminal penalties. Indictment alone under the FCPA can lead to suspension of the right to do business with the U.S. government until the pending claims are resolved. Conviction of a violation of the FCPA can result in long-term disqualification as a government contractor. The termination of a government contract or relationship as a result of our failure to satisfy any of our obligations under laws governing international business practices would have a negative impact on our operations and harm our reputation and ability to procure government contracts. The SEC also may suspend or bar issuers from trading securities on U.S. exchanges for violations of the FCPA’s accounting provisions.

Like the FCPA, the UK Bribery Act and other anti-corruption laws throughout the world similarly prohibit offers and payments made to obtain improper business advantages, including offers or payments to healthcare professionals and other government and non-government officials. These other anti-corruption laws also can result in substantial financial penalties and other collateral consequences.

Various laws, regulations and executive orders also restrict the use and dissemination outside of the U.S., or the sharing with certain non-U.S. nationals, of information classified for national security purposes, as well as certain products and technical data relating to those products. Our expansion outside of the U.S., has required, and will continue to require, us to dedicate additional resources to comply with these laws, and these laws may preclude us from developing, manufacturing, or selling certain drugs and product candidates outside of the U.S., which could limit our growth potential and increase our development costs.

With the ~~recent~~ passage of the CREATES Act, we are exposed to possible litigation and damages by competitors who may claim that we are not providing sufficient quantities of our approved products on commercially reasonable, market-based terms for testing in support of their ANDAs and 505(b)(2) applications.

On December 20, 2019, President Trump signed legislation intended to facilitate the development of generic and biosimilar products. The bill, previously known as the CREATES Act, authorizes sponsors of abbreviated new drug applications (“ANDAs”) and 505(b)(2) applications to file lawsuits against companies holding NDAs that decline to provide sufficient quantities of an approved reference drug on commercially reasonable, market-based terms. Drug products on FDA’s drug shortage list are exempt from these new provisions unless the product has been on the list for more than six continuous months or the FDA determines that the supply of the product will help alleviate or prevent a shortage.

To bring an action under the statute, an ANDA or 505(b)(2) applicant must take certain steps to request the reference product, which, in the case of products covered by a ~~risk evaluation~~Risk Evaluation and ~~mitigation strategy~~Mitigation Strategy with elements to assure safe use, include obtaining authorization from the FDA for the acquisition of the reference product. If the applicant does bring an action for failure to provide a reference product, there are certain affirmative defenses available to the NDA holder, which must be shown by a preponderance of evidence. If the applicant prevails in litigation, it is entitled to a court order directing the NDA holder to provide, ~~without delay,~~

without delay, sufficient quantities of the applicable product on commercially reasonable, market-based terms, plus reasonable attorney fees and costs.

Additionally, the new statutory provisions authorize a federal court to award the product developer an amount “sufficient to deter” the NDA holder from refusing to provide sufficient product quantities on commercially reasonable, market-based terms if the court finds, by a preponderance of the evidence, that the NDA holder did not have a legitimate business justification to delay providing the product or failed to comply with the court’s order. For the purposes of the statute, the term “commercially reasonable, market-based terms” is defined as (1) the nondiscriminatory price at or below the most recent wholesale acquisition cost for the product, (2) a delivery schedule that meets the statutorily defined timetable, and (3) no additional conditions on the sale.

Although we intend to comply fully with the terms of these new statutory provisions, we are still exposed to potential litigation and damages by competitors who may claim that we are not providing sufficient quantities of our approved products on commercially reasonable, market-based terms for testing in support of ANDAs and 505(b)(2) applications. Such litigation would subject us to additional litigation costs, damages and reputational harm, which could lead to lower revenues. The CREATES Act may enable generic competition with XPOVIO and any of our other product candidates, if approved, which could impact our ability to maximize product revenue.

We are subject to governmental export and import controls that could impair our ability to compete in international markets due to licensing requirements and subject us to liability if we are not in compliance with applicable laws.

Our products are subject to export control and import laws and regulations, including the U.S. Export Administration Regulations, U.S. Customs regulations, and various economic and trade sanctions regulations administered by the U.S. Treasury Department’s Office of Foreign Assets Controls. Exports of our products outside of the U.S. must be made in compliance with these laws and regulations. If we fail to comply with these laws and regulations, we and certain of our employees could be subject to substantial civil or criminal penalties, including the possible loss of export or import privileges; fines, which may be imposed on us and responsible employees or managers; and, in extreme cases, the incarceration of responsible employees or managers.

In addition, changes in our products or changes in applicable export or import laws and regulations may create delays in the introduction, provision, or sale of our products in international markets, prevent customers from using our products or, in some cases, prevent the export or import of our products to certain countries, governments or persons altogether. Any limitation on our ability to export, provide, or sell our products could adversely affect our business, financial condition and results of operations.

We have incurred significant losses since inception, expect to continue to incur significant losses, and may never achieve or maintain profitability.

Since inception, we have incurred significant operating losses. Our net loss was ~~$57.4~~$53.6 million for the quarter ended ~~March 31,~~June 30, 2021. As of ~~March 31,~~June 30, 2021, we had an accumulated deficit of ~~$1.1~~$1.2 billion. Although we received our first FDA-approval for XPOVIO in July 2019, we may never attain profitability or positive cash flows from operations. We have historically financed our operations principally through product revenue sales, private placements of our preferred stock, proceeds from our initial public offering and follow-on offerings of common stock, issuance of convertible debt, proceeds from a revenue interest financing agreement and cash generated from our business development activities. Substantially all of our operating losses have resulted from costs incurred in connection with our research and development programs, the pursuit of regulatory approvals within and outside of the U.S., and the commercialization of XPOVIO. We expect to continue to incur significant expenses and operating losses as we continue to commercialize XPOVIO in the U.S. and outside of the U.S. and engage in activities to prepare for the potential approval and commercialization of additional indications for selinexor as well as our other product candidates. The net losses we incur may fluctuate significantly from quarter to quarter.

While we began to generate revenue from the sales of XPOVIO in July 2019 and have received revenue from our license arrangements, such as the partnership we have with Antengene Therapeutics Limited (“Antengene”) for our programs across most of the Asia-Pacific region, there can be no assurance as to the amount or timing of future product or license and other revenues, and we may not achieve profitability for several years, if at all. Our ability to become and remain profitable depends significantly on our success in many areas, including:

We anticipate that our operating and capital expenses will increase as we continue to:

Because of the numerous risks and uncertainties associated with pharmaceutical product development and commercialization, we are unable to accurately predict the timing or amount of our revenue and expenses or when, or if, we will be able to achieve profitability. We cannot be certain that our revenue from sales of XPOVIO alone, in the currently approved indications, will be sufficient for us to become profitable for several years, if at all. We may never generate revenues that are significant or large enough to achieve profitability. Even if we do achieve profitability, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to become and remain profitable would decrease the value of our company and could impair our ability to raise capital, maintain our research and development and commercialization efforts, expand our business and/or continue our operations. A decline in the value of our company could also cause our stockholders to lose all or part of their investment.

We will need additional funding to achieve our business objectives. If we are unable to raise capital when needed or on acceptable terms, we would be forced to delay, reduce or eliminate our research and development programs or commercialization efforts.

Discovering, developing and commercializing products involve time-consuming, expensive and uncertain processes that take years to complete. We have used substantial funds to develop XPOVIO and expect our operating expenses to continue to increase as we continue to commercialize XPOVIO, including for the recently approved indication based on the BOSTON study, conduct further research and development of our product candidates, seek marketing approval and prepare for commercialization of selinexor in additional indications or for our other product candidates, if approved, to the extent that such functions are not the responsibility of a collaborator. Furthermore, we will continue to incur additional costs associated with operating as a public company, hiring additional personnel and expanding our geographical reach. Although currently XPOVIO is commercially available in three indications, we do not anticipate that our revenue from product sales of XPOVIO or any funds we may receive from our collaborators will be sufficient for us to become profitable for several years, if at all. Accordingly, we will need to continue to rely on additional financing to achieve our business objectives.

As of ~~March 31,~~June 30, 2021, we believe that our existing cash, cash equivalents and investments will enable us to fund our current operating and capital expenditure plans for at least twelve months from the date of issuance of the financial statements contained in this Quarterly Report on Form 10-Q. The amount and timing of our future capital requirements will depend on many factors, including, but not limited to:

In addition, the terms of any financing may adversely affect the holdings or the rights of our stockholders. If we raise additional funds by issuing equity securities, dilution to our existing stockholders will result. In addition, as a condition to providing additional funding to us, future investors may demand, and may be granted, rights superior to those of existing stockholders. Moreover, any debt financing, if available, may involve restrictive covenants that could limit our flexibility in conducting future business activities and, in the event of insolvency, would be paid before holders of equity securities received any distribution of corporate assets. Our ability to satisfy and meet any future debt service obligations will depend upon our future performance, which will be subject to financial, business and other factors affecting our operations, many of which are beyond our control.

Even if we believe we have sufficient funds for our current or future operating plans, we may seek additional capital due to favorable market conditions or strategic considerations. Any future fundraising efforts could divert our management’s attention away from their day-to-day activities. Further, adequate additional financing may not be available to us on acceptable terms, or at all. In addition, raising funds in the current economic environment may present additional challenges. For example, any sustained disruption in the capital markets from the COVID-19 pandemic could negatively impact our ability to raise capital and we cannot predict the extent or duration of the macro-economic disruption stemming from the COVID-19 pandemic. If adequate funds are not available to us on a timely basis or on attractive terms, we may be required to delay, reduce or eliminate our research and development programs or any current or future commercialization efforts for one or more of our products or product candidates, any of which could have a material adverse effect on our business, operating results and prospects.

Our Revenue Interest Agreement with HCR, as amended, contains various covenants and other provisions, which, if violated, could result in the acceleration of payments due under such agreement or the foreclosure on the pledged collateral, including all of our present and future assets relating to XPOVIO.

In September 2019, we entered into the Revenue Interest Financing Agreement (“Revenue Interest Agreement”) with HealthCare Royalty Partners III, L.P. and HealthCare Royalty Partners IV, L.P. (“HCR”) and which was amended in June 2021 (the “Amended Revenue Interest Agreement”). Pursuant to the Amended Revenue Interest Agreement, we are required to comply with various covenants relating to the conduct of our business and the commercialization of XPOVIO, including obligations to use commercially reasonable efforts to commercialize our products and limits on our ability to incur or prepay indebtedness, create or incur liens, pay dividends on or repurchase outstanding shares of our capital stock or dispose of assets. In addition, the Amended Revenue Interest Agreement includes customary events of default upon the occurrence of enumerated events, including non-payment of revenue interests, failure to perform certain covenants and the occurrence of insolvency proceedings, specified judgments, specified cross-defaults or specified revocations, or withdrawals or cancellations of regulatory approval for XPOVIO. Upon the occurrence of an event of default and in the event of a change of control, HCR may accelerate payments due under the Amended Revenue Interest Agreement up to ~~$138.8~~$249.8 million, less the aggregate of all of the payments previously paid to HCR. Upon the occurrence of specified material adverse events or the material breach of specified representations and warranties, which will not be considered events of default, HCR may elect to terminate the Amended Revenue Interest Agreement and require us to make payments necessary for HCR to receive ~~$75.0~~$135.0 million, less the aggregate of all of the payments made to date, plus a specified annual rate of return. In the event that we are unable to make such payment, then HCR may be able to foreclose on the collateral that was pledged to HCR, which

consists of all of our present and future assets relating to XPOVIO. Any such foreclosure remedy would significantly and adversely affect us and could result in us losing our interest in such assets.

Our indebtedness could limit cash flow available for our operations, expose us to risks that could adversely affect our business, financial condition and results of operations and impair our ability to satisfy our obligations under the Convertible Senior Notes due 2025 (the “Notes”).

We incurred $172.5 million of indebtedness as a result of the sale of the Notes, ~~and~~ $75.0 million as a result of the initial closing pursuant to the Revenue Interest Agreement ~~that we entered into with HCR in September 2019.~~and $60.0 million following the closing of the Amended Revenue Interest Agreement. We may also incur additional indebtedness to meet future financing needs. Our indebtedness could have significant negative consequences for our security holders and our business, results of operations and financial condition by, among other things:

Our ability to pay the principal of or interest on the Notes or to make cash payments in connection with any conversion of the Notes depends on our future performance, which is subject to economic, financial, competitive and other factors beyond our control. Our business may not generate cash flow from operations in the future sufficient to service the Notes or other future indebtedness and make necessary capital expenditures. In addition, if the impact of the COVID-19 pandemic to our results of operations and business prospects is more severe and prolonged than we currently anticipate, our ability to repay the Notes could be impaired.

We may not have the ability to raise the funds necessary to settle conversions of the Notes in cash, to repurchase the Notes for cash upon a fundamental change, to pay the redemption price for any Notes we redeem or to refinance the Notes, and any future debt we incur may contain limitations on our ability to pay cash upon conversion or repurchase of the Notes.

Holders may require us to repurchase their Notes following a fundamental change at a cash repurchase price generally equal to the principal amount of the Notes to be repurchased, plus accrued and unpaid interest. In addition, upon conversion, unless we elect to deliver solely shares of our common stock to settle conversions (other than paying cash in lieu of delivering any fractional share), we must satisfy the conversion in cash. If we do not have enough available cash at the time we are required to repurchase the Notes, pay cash amounts due upon conversion or redemption of the Notes or refinance the Notes, we may be required to adopt one or more alternatives, such as selling assets, restructuring indebtedness or obtaining additional debt financing or equity capital on terms that may be onerous or highly dilutive. Our ability to refinance the Notes or other future indebtedness will depend on the capital markets, our financial condition at such time and our obligations under any other existing indebtedness in effect at such time. We may not be able to engage in any of these activities on desirable terms, or at all, which could result in a default on our debt obligations, including the Notes. In addition, our ability to repurchase the Notes, to pay cash upon conversion or redemption of the Notes or to refinance the Notes may be limited by law, regulatory authority or agreements governing any future indebtedness that we may incur. Our failure to repurchase the Notes at a time when the repurchase is required by the indenture governing the Notes or to pay cash upon conversion of the Notes as required by the indenture would constitute a default under the indenture. A default under the indenture or the fundamental change itself could also lead to a default under agreements governing our future indebtedness, if any. Moreover, the occurrence of a fundamental change under the indenture could constitute an event of default under any such agreements. If the repayment of the related indebtedness were to be accelerated after any applicable notice or grace periods, we may not have sufficient funds to repay the indebtedness and repurchase the Notes or to pay cash upon conversion of the Notes.

The conditional conversion feature of the Notes, if triggered, may adversely affect our financial condition and operating results.

In the event the conditional conversion feature of the Notes is triggered, holders of Notes will be entitled to convert the Notes at any time during specified periods at their option. If one or more holders elect to convert their Notes, unless we elect to satisfy our conversion obligation by delivering solely shares of our common stock (other than paying cash in lieu of delivering any fractional share), we would be required to settle a portion or all of our conversion obligation in cash, which could adversely affect our liquidity.

In addition, even if holders do not elect to convert their Notes, we could be required under applicable accounting rules to reclassify all or a portion of the outstanding principal amount of the Notes as a current rather than long-term liability, which would result in a material reduction of our net working capital.

The accounting method for convertible debt securities that may be settled in cash, such as the Notes, could have a material effect on our reported financial results.

Convertible debt instruments (such as the Notes) that may be settled entirely or partly in cash are currently eligible to be accounted for utilizing the treasury stock method, the effect of which is that the shares issuable upon conversion of the Notes are not included in the calculation of diluted earnings per share except to the extent that the conversion value of the Notes exceeds their principal amount. Under the treasury stock method, for diluted earnings per share purposes, the transaction is accounted for as if the number of shares of common stock that would be necessary to settle such excess, if we elected to settle such excess in shares, are issued. We cannot be sure that the accounting standards in the future will continue to permit the use of the treasury stock method. If we are unable to use the treasury stock method in accounting for the shares issuable upon conversion of the Notes, then our diluted earnings per share would be adversely affected.

Furthermore, if any of the conditions to the convertibility of the Notes is satisfied, then we may be required under applicable accounting standards to reclassify the liability carrying value of the Notes as a current, rather than a long-term, liability. This reclassification could be required even if no holders convert their Notes and could materially reduce our reported working capital.

Raising additional capital may cause dilution to our stockholders, restrict our operations or require us to relinquish rights to our product candidates.

Until such time, if ever, as we can generate substantial revenues from the sale of our products, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances and/or licensing arrangements. We do not have any committed external source of funds. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interests of stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of common stockholders. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. For example, during the term of the Amended Revenue Interest Agreement, we cannot make any voluntary or optional cash payment or prepayment on our existing convertible debt and cannot enter into any new debt without the consent of HCR.

If we raise funds through further collaborations, strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our research and drug development or current or future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Unstable market and economic conditions may have serious adverse consequences on our business, financial condition and stock price.

Global credit and financial markets have experienced extreme disruptions over the past several years. Such disruptions have resulted, and could in the future result, in diminished liquidity and credit availability, declines in consumer confidence, declines in economic growth, increases in unemployment rates and uncertainty about economic stability. For example, the COVID-19 pandemic has resulted in businesses suspending or terminating global operations and travel, self-imposed or government-mandated quarantines, and an overall slowdown of economic activity in many areas. Our general business strategy may be compromised by economic downturns, a volatile business environment and unpredictable and unstable market conditions, such as the current global situation resulting from the COVID-19 pandemic. If the equity and credit markets deteriorate, it may make any necessary equity or debt financing more difficult to secure, more costly or more dilutive. Failure to secure any necessary financing in a timely manner and on favorable terms could harm our growth strategy, financial performance and stock price and could require us to delay or abandon plans with respect to our business, including clinical development plans. In addition, there is a risk that one or more of our current service providers, manufacturers or other third parties with which we conduct business may not survive difficult economic times, including the current global situation resulting from the COVID-19 pandemic, which could directly affect our ability to attain our operating goals on schedule and on budget.

We depend on collaborations with third parties for certain aspects of the development, marketing and/or commercialization of XPOVIO and/or our product candidates. If those collaborations are not successful, or if we are not able to maintain our existing collaborations or establish additional collaborations, we may have to alter our development and commercialization plans and may not be able to capitalize on the market potential of XPOVIO or our product candidates.

Our drug development programs and the commercialization of our products and product candidates, if approved, require substantial additional cash to fund expenses. We expect to maintain our existing collaborations and collaborate with additional pharmaceutical and biotechnology companies for certain aspects of the development, marketing and/or commercialization of our products and product candidates within and outside of the U.S. For example, we are parties to a license arrangement with Antengene and distribution agreements with Promedico Ltd. and FORUS Therapeutics Inc. for the development, marketing and/or commercialization of selinexor in certain geographies outside of the U.S. In addition, we intend to seek one or more collaborators to aid in the further development, marketing and/or commercialization of selinexor and our other SINE compounds for indications outside of oncology. For example, we expect to rely on partners to develop and commercialize our products outside of the U.S. All of the risks relating to product development, regulatory approval and commercialization described in this Quarterly Report on Form 10-Q also apply to the activities of our collaborators.

Potential collaborators include large and mid-size pharmaceutical companies, regional and national pharmaceutical companies and biotechnology companies and we face significant competition in seeking appropriate collaborators, including as a result of a significant number of recent business combinations among large pharmaceutical companies that have reduced the number of potential collaborators. Whether we reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration and the proposed collaborator’s evaluation of a number of factors. Those factors may include the design or results of clinical trials, the likelihood of approval by the FDA or foreign regulatory authorities, the potential market for the product or product candidate, the costs and complexities of manufacturing and delivering such product or product candidate to patients, the potential of competing products, the existence of uncertainty with respect to our ownership of intellectual property, which can exist if there is a challenge to such ownership without regard to the merits of the challenge, and industry and market conditions generally. The collaborator may also consider alternative product candidates or technologies for similar indications that may be available to collaborate on and whether such a collaboration could be more attractive than the one with us.

Collaborations are complex and time-consuming to negotiate and document. We may not be able to negotiate collaborations on a timely basis, on acceptable terms, or at all, or we may be restricted under then-existing collaboration agreements from entering into future agreements on certain terms with potential collaborators. If we are unable to maintain our current collaboration agreements or enter into new collaboration agreements, we may have to curtail, reduce or delay the development or commercialization programs for our products or product candidates, or increase our expenditures and undertake development or commercialization activities at our own expense. If we elect to increase our expenditures to fund and undertake development or commercialization activities on our own, we may need to obtain additional expertise and additional capital, which may not be available to us on acceptable terms, or at all. If we do not have sufficient funds or expertise to undertake the necessary development and commercialization activities, we may not be able to further develop our product candidates or bring them to market and generate product revenue.

Our ability to generate revenues from these arrangements will depend on our collaborators’ abilities to successfully perform the functions assigned to them in these arrangements and our collaboration agreements may not lead to the development or commercialization of our products or product candidates in the most efficient manner, or at all, and may result in lower product revenues or profitability to us than if we were to market and sell these products ourselves. In connection with any such arrangements with third parties, we will likely have limited control over the amount and timing of resources that our collaborators dedicate to the development, marketing and/or commercialization of our products or product candidates. Further, if our collaborations do not result in the successful development and commercialization of our products or product candidates or if one of our collaborators terminates its agreement with us, we may not receive any future milestone or royalty payments under the collaboration. If we do not receive the funding we expect under these agreements, the development and commercialization of our products or product candidates could be delayed and we may need additional resources to develop product candidates.

Further, our ability to enter into new collaboration arrangements and the successful execution of our current arrangements by our collaborators could be negatively impacted by the COVID-19 pandemic, including as a result of businesses suspending or terminating global operations and travel, self-imposed or government-mandated quarantines, and a prolonged economic downturn. If our or our third-party collaborators are so affected, our business prospects and results of operations could be severely adversely impacted.

Collaborations involving our products and product candidates pose the following risks to us:

If any of these events occurs, the market potential of our products and product candidates could be reduced, and our business could be materially harmed.

If we are unable to establish and maintain our agreements with third parties to distribute XPOVIO to patients, our results of operations and business could be adversely affected.

We rely on third parties to commercially distribute XPOVIO to patients. For example, we have contracted with a limited number of specialty pharmacies, which sell XPOVIO directly to patients, and specialty distributors, which sell XPOVIO to healthcare entities who then resell XPOVIO to patients. While we have entered into agreements with each of these pharmacies and distributors to distribute XPOVIO in the U.S., they may not perform as agreed or they may terminate their agreements with us. We may also need to enter into agreements with additional pharmacies or distributors, and there is no guarantee that we will be able to do so on a timely basis, at commercially reasonable terms, or at all. If we are unable to maintain and, if needed, expand, our network of specialty pharmacies and specialty distributors, we would be exposed to substantial distribution risk.

The use of specialty pharmacies and specialty distributors involves certain risks, including, but not limited to, risks that these organizations will:

Any such events may result in decreased product sales, which would harm our results of operations and business.

We rely on third parties as we conduct our clinical trials and some aspects of our research and preclinical studies, and those third parties may not perform satisfactorily, including failing to meet deadlines for the completion of such trials, research or testing.

We rely on some third parties, such as CROs, clinical data management organizations, medical institutions and clinical investigators, as we conduct our clinical trials. We currently rely and expect to continue to rely on third parties to conduct some aspects of our research and preclinical studies. Any of these third parties may terminate their engagements with us at any time. If we need to enter into alternative arrangements, it would delay our drug development activities.

Our reliance on these third parties for research and development activities reduces our control over these activities but does not relieve us of our responsibilities. For example, we remain responsible for ensuring that each of our clinical trials is conducted in accordance with the general investigational plan and protocols for the trial. Moreover, the FDA requires us to comply with GCP standards when conducting, recording and reporting the results of clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of trial participants are protected. The EMA also requires us to comply with comparable standards. Regulatory authorities ensure compliance with these requirements through periodic inspections of trial sponsors, principal investigators and trial sites. Our reliance on third parties that we do not control does not relieve us of these responsibilities and requirements. If we or any of the third parties that we rely on in connection with our clinical trials fail to comply with applicable requirements, the clinical data generated in our clinical trials may be deemed unreliable and the FDA, EMA or other comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical trials comply with such requirements. We also are required to register ongoing clinical trials and post the results of completed clinical trials on a government-sponsored database, ClinicalTrials.gov, within certain timeframes. Failure to do so can result in fines, adverse publicity and civil and criminal sanctions.

Furthermore, these third parties may also have relationships with other entities, some of which may be our competitors. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or conduct our clinical trials in accordance with regulatory requirements or our stated protocols, we will not be able to obtain, or may be delayed in obtaining, marketing approvals for our product candidates and will not be able to, or may be delayed in our efforts to, successfully commercialize our products. In such an event, our financial results and the commercial prospects for our product candidates could be harmed, our costs could increase and our ability to generate revenues could be delayed, impaired or foreclosed.

We also expect to rely on other third parties to store and distribute drug supplies for our clinical trials. Any performance failure on the part of such third parties could delay clinical development or marketing approval of our product candidates or commercialization of our products, producing additional losses and depriving us of potential product revenue.

In addition, as discussed above, the third-parties upon whom we rely to conduct our clinical trials could be negatively impacted as a result of disruptions caused by the COVID-19 pandemic, including difficulties in initiating clinical sites or enrolling participants, diversion of healthcare resources away from clinical trials, travel or quarantine policies, and other factors. If these third parties are so affected, our business prospects and results of operations could be severely adversely impacted.

We rely on third parties to conduct investigator-sponsored clinical trials of selinexor and our other product candidates. Any failure by a third party to meet its obligations with respect to the clinical development of our product candidates may delay or impair our ability to obtain regulatory approval for selinexor and our other product candidates.

We rely on academic and private non-academic institutions to conduct and sponsor clinical trials relating to selinexor and our other product candidates. We do not control the design or conduct of the investigator-sponsored trials, and it is possible that the FDA or foreign regulatory authorities will not view these investigator-sponsored trials as providing adequate support for future clinical

trials, whether controlled by us or third parties, for any one or more reasons, including elements of the design, execution of the trials, safety concerns or other trial results.

Such arrangements will provide us certain information rights with respect to the investigator-sponsored trials, including access to and the ability to use and reference the data, including for our own regulatory filings, resulting from the investigator-sponsored trials. However, we do not have control over the timing and reporting of the data from investigator-sponsored trials, nor do we own the data from the investigator-sponsored trials. If we are unable to confirm or replicate the results from the investigator-sponsored

trials or if negative results are obtained, we would likely be further delayed or prevented from advancing clinical development of our product candidates. Further, if investigators or institutions breach their obligations with respect to the clinical development of our product candidates, or if the data proves to be inadequate compared to the first-hand knowledge we might have gained had the investigator-sponsored trials been sponsored and conducted by us, then our ability to design and conduct any future clinical trials ourselves may be adversely affected.

Additionally, the FDA or foreign regulatory authorities may disagree with the sufficiency of our right to reference the preclinical, manufacturing or clinical data generated by these investigator-sponsored trials, or our interpretation of preclinical, manufacturing or clinical data from these investigator-sponsored trials. If so, the FDA or foreign regulatory authorities may require us to obtain and submit additional preclinical, manufacturing, or clinical data before we may initiate our planned trials and/or may not accept such additional data as adequate to initiate our planned trials.

We are completely dependent on third parties for the manufacture of our products and product candidates and any difficulties, disruptions, delays or unexpected costs, or the need to find alternative sources, could adversely affect our results of operations, profitability and future business prospects.

We do not own or operate, and currently have no plans to establish, any manufacturing facilities for our products or product candidates. We currently rely, and expect to continue to rely, on third-party contract manufacturers to manufacture our products and product candidates for our commercial and clinical use.

Facilities used by our third-party manufacturers may be inspected by the FDA after we submit an NDA and before potential approval of the product candidate and are also subject to ongoing periodic unannounced inspections by the FDA for compliance with cGMP and other regulatory requirements following approval. Similar regulations apply to manufacturers of our product candidates for use or sale in foreign countries. We do not control the manufacturing processes of, and are completely dependent on, our third-party manufacturers for compliance with the applicable regulatory requirements for the manufacture of our products and product candidates. Third-party manufacturers may not be able to comply with cGMP regulations or similar regulatory requirements outside of the U.S. If our manufacturers cannot successfully manufacture material that conforms to our specifications and the strict regulatory requirements of the FDA and any applicable foreign regulatory authority, they will not be able to secure and/or maintain regulatory approval for their manufacturing facilities. If these facilities are not approved for commercial manufacture or are not able to maintain approval, we may need to find alternative manufacturing facilities, which could significantly impact our ability to develop, obtain regulatory approval for or market our products or product ~~candidate~~candidates as alternative qualified manufacturing facilities may not be available on a timely or cost-efficient basis, or at all. Failure by any of our manufacturers to comply with applicable cGMP regulations or other regulatory requirements could result in sanctions being imposed on us or the contract manufacturer, including fines, injunctions, civil penalties, delays, suspensions or withdrawals of approvals, operating restrictions, interruptions in supply and criminal prosecutions, any of which could significantly and adversely affect supplies of our products or product candidates and have a material adverse impact on our business, financial condition and results of operations.

We currently have long-term supply agreements with our third-party contract manufacturers to manufacture the clinical and commercial supplies of the drug product for XPOVIO. Our ability to have our products manufactured in sufficient quantities and at acceptable costs to meet our commercial demand and clinical development needs is dependent on the uninterrupted and efficient operation of our third-party contract manufacturers’ facilities. Reliance on third-party manufacturers entails risks, including:

We currently rely on a single source supplier for our active pharmaceutical ingredient and our drug product manufacturing requirements. Any performance failure on the part of our existing or future manufacturers could delay clinical development, marketing approval or commercialization of our products or product candidates. For example, as a result of the COVID-19 pandemic, our suppliers and contract manufacturers could be disrupted by worker absenteeism, quarantines, or other travel or health-related

restrictions or could incur increased costs associated with ensuring the safety and health of their personnel. If our suppliers or contract manufacturers are so affected, our supply chain could be disrupted, our product shipments could be delayed, our costs could be increased and our business could be adversely affected. If our current contract manufacturers cannot perform as agreed, we may be required to replace those manufacturers. Although we believe that there are several potential alternative manufacturers who could manufacture our products and product candidates, we could incur added costs and delays in identifying and qualifying any such replacement. Consequently, we may not be able to reach agreement with third-party manufacturers on satisfactory terms, which could negatively impact our XPOVIO revenues or delay commercialization of any product candidates that are subsequently approved.

If, because of the factors discussed above, we are unable to have our products manufactured on a timely or sufficient basis, we may not be able to meet clinical development needs or commercial demand for our products or product candidates or we may not be able to manufacture our products in a cost-effective manner. As a result, we may lose sales, fail to generate projected revenues or suffer development or regulatory setbacks, any of which could have an adverse impact on our profitability and future business prospects.

If we are unable to obtain and maintain patent protection for our products or product candidates and other discoveries, or if the scope of the patent protection obtained is not sufficiently broad, our competitors could develop and commercialize drugs and other discoveries similar or identical to ours, and our ability to successfully commercialize our products or product candidates and other discoveries may be adversely affected.

Our success depends in large part on our ability to obtain and maintain patent protection in the U.S. and other countries with respect to our proprietary products and product candidates and other discoveries. We seek to protect our proprietary position by filing patent applications in the U.S. and abroad related to our novel products and product candidates and other discoveries that are important to our business. As of ~~April 29,~~July 28, 2021, 8487 patents were in force that relate to XPO1 inhibitors, including composition of matter patents for selinexor, verdinexor and eltanexor in the U.S., and their use in targeted therapeutics. In addition, 1720 patents were in force that relate to our PAK4/NAMPT inhibitors, including two composition of matter patents for KPT-9274 in the U.S. and its use in targeted therapeutics. We cannot be certain that any other patents will issue with claims that cover any of our key products, product candidates or other discoveries.

The patent prosecution process is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. It is also possible that we will fail to identify patentable aspects of our research and development output before it is too late to obtain patent protection.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has in recent years been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of our patent rights are highly uncertain. Our pending and future patent applications may not result in patents being issued which protect our product candidates or other discoveries, or which effectively prevent others from commercializing competitive drugs and discoveries. Changes in either the patent laws or interpretation of the patent laws in the U.S. and other countries may diminish the value of our patents or narrow the scope of our patent protection.

The laws of foreign countries may not protect our rights to the same extent as the laws of the U.S. For example, in some foreign jurisdictions, our ability to secure patents based on our filings in the U.S. may depend, in part, on our ability to timely obtain assignment of rights to the invention from the employees and consultants who invented the technology. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the U.S. and other jurisdictions are typically not published until 18 months after filing, or in some cases not at all. Therefore, we cannot be certain that we were the first to make the inventions claimed in our patents or pending patent applications, or that we were the first to file for patent protection of such inventions.

Assuming the other requirements for patentability are met, prior to March 2013, in the U.S., the first to invent the claimed invention was entitled to the patent, while outside of the U.S., the first to file a patent application is entitled to the patent. In March 2013, the U.S. transitioned to a first-inventor-to-file system in which, assuming the other requirements for patentability are met, the

first inventor to file a patent application is entitled to the patent. We may be subject to a third-party preissuance submission of prior art to the U.S. Patent and Trademark Office (“USPTO”) or become involved in opposition, derivation, revocation, reexamination, or post-grant or inter partes review or interference proceedings challenging our patent rights or the patent rights of others. An adverse determination in any such submission, proceeding or litigation could reduce the scope of, or invalidate, our patent rights, allow third parties to commercialize our discoveries or drugs and compete directly with us, without payment to us, or result in our inability to manufacture or commercialize drugs without infringing third-party patent rights.

Even if our patent applications issue as patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors from competing with us or otherwise provide us with any competitive advantage. Our competitors may be able to circumvent our patents by developing similar or alternative discoveries or drugs in a non-infringing manner.

The issuance of a patent is not conclusive as to its inventorship, scope, validity or enforceability, and our patents may be challenged in the courts or patent offices in the U.S. and abroad. Such challenges may result in loss of exclusivity or in patent claims being narrowed, invalidated or held unenforceable, which could limit our ability to stop others from using or commercializing similar or identical discoveries and drugs, or limit the duration of the patent protection of our products, product candidates and discoveries. Given the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our patent portfolio may not provide us with sufficient rights to exclude others from commercializing drugs similar or identical to ours.

We may become involved in lawsuits to protect or enforce our patents and other intellectual property rights, which could be expensive, time-consuming and unsuccessful.

Competitors or commercial supply companies or others may infringe our patents and other intellectual property rights. For example, we are aware of third parties selling a version of our lead product candidate for research purposes, which may infringe our intellectual property rights. To counter such infringement, we may advise such companies of our intellectual property rights, including, in some cases, intellectual property rights that provide protection for our lead product candidates, and demand that they stop infringing those rights. Such demand may provide such companies the opportunity to challenge the validity of certain of our intellectual property rights, or the opportunity to seek a finding that their activities do not infringe our intellectual property rights. We may also be required to file infringement actions, which can be expensive and time-consuming. In an infringement proceeding, a defendant may assert and a court may agree with a defendant that a patent of ours is invalid or unenforceable, or may refuse to stop the other party from using the intellectual property at issue. An adverse result in any litigation could put one or more of our patents at risk of being invalidated or interpreted narrowly. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation.

Third parties may initiate legal proceedings alleging that we are infringing their intellectual property rights, the outcome of which would be uncertain and could have a material adverse effect on the success of our business.

Our commercial success depends upon our ability and the ability of any current and future collaborators to develop, manufacture, market and sell XPOVIO and our product candidates and use our proprietary technologies without infringing the proprietary rights of third parties. We may become party to, or threatened with, future adversarial proceedings or litigation regarding intellectual property rights with respect to our products or product candidates and technology, including interference proceedings before the USPTO. Third parties may assert infringement claims against us based on existing patents or patents that may be granted in the future. No litigation asserting such infringement claims is currently pending against us, and we have not been found by a court of competent jurisdiction to have infringed a third party’s intellectual property rights. If we are found to infringe or think there is a risk we may be found to infringe, a third party’s intellectual property rights, we could be required or choose to obtain a license from such third party to continue developing, marketing and selling our drugs, product candidates and technology. However, we may not be able to obtain any required license on commercially reasonable terms, or at all. Even if we were able to obtain a license, it could be non-exclusive, thereby giving our competitors access to the same intellectual property licensed to us. We could be forced, including by court order, to cease commercializing the infringing intellectual property or drug or to cease using the infringing technology. In addition, we could be found liable for monetary damages. A finding of infringement could prevent us from commercializing our products or product candidates or force us to cease some of our business operations, which could materially harm our business. Claims that we have misappropriated the confidential information or trade secrets of third parties could have a similar negative impact on our business.

We may be subject to claims that our employees have wrongfully used or disclosed alleged trade secrets of their former employers.

Many of our employees were previously employed at universities or other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Although we try to ensure that our employees do not use the proprietary

information or know-how of others in their work for us, we may be subject to claims that we or these employees have used or disclosed intellectual property, including trade secrets or other proprietary information, of any such employee’s former employer. Although we have no knowledge of any such claims being alleged to date, if such claims were to arise, litigation may be necessary to defend against any such claims. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management.

Intellectual property litigation could cause us to spend substantial resources and distract our personnel from their normal responsibilities.

Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses and could distract our technical and management personnel from their normal responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a material adverse effect on the price of our common stock. Such litigation or proceedings could substantially increase our operating losses and reduce the resources available for development activities or any future sales, marketing or distribution activities. We may not have sufficient financial or other resources to adequately conduct such litigation or proceedings. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their greater financial resources. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could have a material adverse effect on our ability to compete in the marketplace.

Obtaining and maintaining our patent protection depends on compliance with various procedural, documentary, fee payment and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated for non-compliance with these requirements.

Periodic maintenance fees, renewal fees, annuity fees and various other governmental fees on patents and/or applications will be due to the USPTO and various foreign patent offices at various points over the lifetime of the patents and/or applications. We have systems in place to remind us to pay these fees, and we rely on our outside counsel to pay these fees when due. Additionally, the USPTO and various foreign patent offices require compliance with a number of procedural, documentary, fee payment and other similar provisions during the patent application process. We employ reputable law firms and other professionals to help us comply with such provisions, and in many cases, an inadvertent lapse can be cured by payment of a late fee or by other means in accordance with rules applicable to the particular jurisdiction. However, there are situations in which non-compliance can result in abandonment or lapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. If such an event were to occur, it could have a material adverse effect on our business.

If we do not successfully extend the term of patents covering our product candidates under the Hatch-Waxman Amendments and similar foreign legislation, our business may be materially harmed.

Depending upon the timing, duration and conditions of FDA marketing approval, if any, of our products or product candidates, one or more of our U.S. patents may be eligible for patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, referred to as the Hatch-Waxman Amendments. The Hatch-Waxman Amendments permit a patent term extension of up to five years for one patent covering an approved product as compensation for effective patent term lost during product development and the FDA regulatory review process. However, we may not receive an extension if we fail to apply within applicable deadlines, fail to apply prior to expiration of relevant patents or otherwise fail to satisfy applicable requirements. Moreover, the length of the extension could be less than we request. The total patent term, including the extension period, may not exceed 14 years following FDA approval. Accordingly, the length of the extension, or the ability to even obtain an extension, depends on many factors.

In the U.S., only a single patent can be extended for each qualifying FDA approval, and any patent can be extended only once and only for a single product. Laws governing analogous patent term extensions in foreign jurisdictions vary widely, as do laws governing the ability to obtain multiple patents from a single patent family. Because both selinexor and verdinexor are protected by a single family of patents and applications, we may not be able to secure patent term extensions for both of these product candidates in all jurisdictions where these product candidates are approved.

If we are unable to obtain a patent term extension for a product or product candidate or the term of any such extension is less than we request, the period during which we can enforce our patent rights for that product or product candidate, if any, in that jurisdiction will be shortened and our competitors may obtain approval to market competing products sooner. As a result, our revenue could be materially reduced.

If we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to seeking patents for our products, product candidates and other discoveries, we also rely on trade secrets, including unpatented know-how, technology and other proprietary information, to maintain our competitive position. We seek to protect these trade secrets, in part, by entering into non-disclosure and confidentiality agreements with parties who have access to them, such as our employees, outside scientific collaborators, CROs, contract manufacturers, consultants, advisors and other third parties. We also enter into confidentiality and invention or patent assignment agreements with our employees and consultants. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and we may not be able

to obtain adequate remedies for such breaches. To the extent that we are unable to timely enter into confidentiality and invention or patent assignment agreements with our employees and consultants, our ability to protect our business through trade secrets and patents may be harmed. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts inside and outside of the U.S. are less willing or unwilling to protect trade secrets. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor, we would have no right to prevent them from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor, our competitive position would be harmed. To the extent inventions are made by a third party under an agreement that does not grant us an assignment of their rights in inventions, we may choose or be required to obtain a license.

Not all of our trademarks are registered. Failure to secure those registrations could adversely affect our business.

As of ~~April 29,~~July 28, 2021, we have trademark registrations in the U.S. for KARYOPHARM THERAPEUTICS, our ~~name and~~color logo, and a combination of the two, XPOVIO, PORE for our online research portal, and KARYFORWARD and our KARYFORWARD logo for our financial aid and charitable services. We also have pending applications in the U.S. to register ~~KARYFORWARD~~KARYOPHARM alone, and our logo in greyscale, for pharmaceuticals, and the KARYFORWARD logo for a SaaS portal related to our financial aid and charitable services. Outside the U.S., XPOVIO is registered or pending in 46 additional jurisdictions, and is registered in Katakana in Japan, Hangul in South Korea, and Chinese characters in Taiwan. The KARYFORWARD logo is registered or pending in four jurisdictions outside the U.S. We also have registrations or applications for eight additional possible drug names in numerous foreign jurisdictions. If we do not secure registrations for our trademarks, we may encounter more difficulty in enforcing them against third parties than we otherwise would, which could adversely affect our business. During trademark registration proceedings in the U.S. and foreign jurisdictions, we may receive rejections. We are given an opportunity to respond to those rejections, but we may not be able to overcome such rejections. In addition, in the USPTO and in comparable agencies in many foreign jurisdictions, third parties are given an opportunity to oppose pending trademark applications and to seek to cancel registered trademarks. Opposition or cancellation proceedings may be filed against our trademarks, and our trademarks may not survive such proceedings.

In addition, any proprietary name we propose to use with our key product candidates in the U.S. must be approved by the FDA, regardless of whether we have registered it, or applied to register it, as a trademark. The FDA typically conducts a review of proposed drug names, including an evaluation of potential for confusion with other drug names. If the FDA objects to any of our proposed proprietary drug names for any of our product candidates, if approved, we may be required to expend significant additional resources in an effort to identify a suitable proprietary drug name that would qualify under applicable trademark laws, not infringe the existing rights of third parties and be acceptable to the FDA.

Our future success depends on our ability to retain key members of our management team and to attract, retain and motivate qualified personnel.

We are highly dependent on the management, technical and scientific expertise of principal members of our management and scientific teams, including our Chief Executive Officer. Although we have entered into formal employment agreements with our executive officers, these agreements do not prevent them from terminating their employment with us at any time. We do not maintain “key person” insurance for any of our executives or other employees. The loss of the services of any of our key employees could impede the achievement of our research, development, commercialization and other business objectives.

Recruiting and retaining qualified scientific, clinical, manufacturing and sales and marketing personnel is critical to our success. We may not be able to attract and retain these personnel on acceptable terms given the competition among numerous pharmaceutical and biotechnology companies for similar personnel. We also experience competition for the hiring of scientific and clinical personnel from universities and research institutions. In addition, we rely on consultants and advisors, including scientific and clinical advisors, to assist us in formulating our research and development and commercialization strategies. Our consultants and advisors may be employed by employers other than us and may have commitments under consulting or advisory contracts with other entities that may limit their availability to us.

In addition, Dr. Kauffman, a member of our Board, and Dr. Shacham, our Chief Scientific Officer, are married to each other. Our business may be harmed if there are personal or professional conflicts between them, and their relationship could negatively impact the operations of the Company or our working environment.

We have expanded and expect to continue to expand our development, regulatory and sales, marketing and distribution capabilities, and as a result, we may encounter difficulties in managing our growth, which could disrupt our operations.

We have experienced and expect to continue to experience significant growth in the number of our employees and the scope of our operations, particularly in the areas of drug development, clinical operations, regulatory affairs, sales, marketing and distribution. To manage our current and anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. Due to our limited financial resources and the limited experience of our management team in managing such growth, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our business plans or disrupt our operations.

Our business and operations may be materially adversely affected in the event of information technology system failures or security breaches, and the costs and consequences of implementing data protection measures could be significant.

Despite the implementation of security measures, our internal computer systems, and those of our CROs and other third parties on which we rely, are vulnerable to damage from computer viruses, unauthorized access, natural disasters, fire, terrorism, war and telecommunication and electrical failures. Such systems are also vulnerable to service interruptions or to security breaches from inadvertent or intentional actions by our employees, third-party vendors and/or business partners, or from cyber incidents by malicious third parties. Cyber incidents are increasing in their frequency, sophistication and intensity, and have become increasingly difficult to detect. Cyber incidents could include the deployment of harmful malware, ransomware, denial-of-service attacks, unauthorized access to or deletion of files, social engineering and other means to affect service reliability and threaten the confidentiality, integrity and availability of information. Cyber incidents also could include phishing attempts or e-mail fraud to cause payments or information to be transmitted to an unintended recipient. We could be subject to risks caused by misappropriation, misuse, leakage, falsification or intentional or accidental release or loss of information maintained in the information systems and networks of our company, including personal data of our employees. In addition, we face other kinds of risks related to our commercial and personal data, including lost or stolen devices or other systems (including paper records) that collect and store our personal and commercial information.

If such an event were to occur and cause interruptions in our operations, it could result in a material disruption of our development and commercialization programs and our business operations, whether due to a loss of our trade secrets or other proprietary information or other similar disruptions. For example, the loss of clinical trial data from completed, ongoing or planned clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data or applications, or inappropriate disclosure of confidential or proprietary information, we could incur liability, our reputation or competitive position could be damaged, and the further development and commercialization of our products or product candidates could be delayed or halted. In addition, we may in certain instances be required to provide notification to individuals or others in connection with the loss of their personal or commercial information.

If a material breach of our security or that of our vendors occurs, our financial or other confidential information could be compromised and could adversely affect our business or result in legal proceedings. In addition, the cost and operational consequences of implementing further data protection measures could be significant. The development and maintenance of these systems, controls and processes is costly and requires ongoing monitoring and updating as technologies change and efforts to overcome security measures become more sophisticated. Moreover, the possibility of these events occurring cannot be eliminated entirely.

Provisions in our corporate charter documents and under Delaware law could make an acquisition of us, which may be beneficial to our stockholders, more difficult and may prevent attempts by our stockholders to replace or remove our current management.

Provisions in our corporate charter and our bylaws may discourage, delay or prevent a merger, acquisition or other change in control of us that stockholders may consider favorable, including transactions in which stockholders might otherwise receive a premium for their shares. These provisions could also limit the price that investors might be willing to pay in the future for shares of our common stock, thereby depressing the market price of our common stock. In addition, because our board of directors is responsible for appointing the members of our management team, these provisions may frustrate or prevent any attempts by our

stockholders to replace or remove our current management by making it more difficult for stockholders to replace members of our board of directors. Among other things, these provisions:

Moreover, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which prohibits a person who owns in excess of 15% of our outstanding voting stock from merging or combining with us for a period of three years after the date of the transaction in which the person acquired in excess of 15% of our outstanding voting stock, unless the merger or combination is approved in a prescribed manner.

The price of our common stock has been and may continue to be volatile and your investment in our stock could decline in value or fluctuate significantly, including as a result of analysts’ activities.

Our stock price has been, and may continue to be, volatile and your investment in our stock could decline or fluctuate significantly. ~~Since April 29, 2020, our~~Our common stock price has ranged from ~~$8.96~~$7.78 to ~~$24.53.~~$18.17 in the 52 week period ended July 28, 2021. On ~~April 29,~~July 28, 2021, the closing sale price of our common stock on the Nasdaq Global Select Market was ~~$9.56~~$8.79 per share. The stock market in general and the market for pharmaceutical and biotechnology companies in particular have experienced extreme volatility that has often been unrelated to the operating performance of particular companies, such as the ~~recent~~ response to the ongoing COVID-19 pandemic and related world-wide economic disruptions. The market price for our common stock may be influenced by many factors, including:

In addition, the trading market for our common stock relies, in part, on the research and reports that industry or financial analysts publish about us or our business. Our stock price could decline significantly if we fail to meet or exceed analysts’ forecasts and expectations or if one or more of the analysts covering our business downgrade their evaluations of our stock. Further, if one or more of these analysts cease to cover our stock, we could lose visibility in the market for our stock, which in turn could cause our stock price to decline.

Securities or other litigation could result in substantial costs and may divert management’s time and attention from our business.

Securities class action litigation is often been brought against a company following a decline in the market price of its securities. This risk is especially relevant for us because pharmaceutical companies have experienced significant stock price volatility in recent years and we are therefore a target of this type of litigation. For example, we are currently subject to a ~~securities class action litigation and a~~ shareholder derivative lawsuit initiated against us and certain of our executive officers and directors and certain other defendants, as described further in Part II, Item 1, “Legal Proceedings” in Part II, Item 1, “Legal Proceedings” in this Quarterly Report on Form 10-Q. We may face additional securities class action litigation or other litigation if we fail to successfully commercialize XPOVIO, or if we cannot obtain regulatory approvals for, or if we otherwise fail to successfully commercialize and launch, our product candidates.

The outcome of litigation is necessarily uncertain, and we could be forced to expend significant resources in the defense of such suits, and we may not prevail. Monitoring and defending against legal actions is time-consuming for our management and detracts from our ability to fully focus our internal resources on our business activities. In addition, we may incur substantial legal fees and costs in connection with any such litigation. We have not established any reserves for any potential liability relating to any such potential lawsuits. It is possible that we could, in the future, incur judgments or enter into settlements of claims for monetary damages. We currently maintain insurance coverage for some of these potential liabilities. Other potential liabilities may not be covered by insurance, insurers may dispute coverage or the amount of insurance may not be enough to cover damages awarded. In addition, certain types of damages may not be covered by insurance, and insurance coverage for all or certain forms of liability may become unavailable or prohibitively expensive in the future. A decision adverse to our interests on one or more legal matters or litigation could result in the payment of substantial damages, or possibly fines, and could have a material adverse effect on our reputation, financial condition and results of operations.

We have broad discretion in the use of our cash, cash equivalents and investments and may not use them effectively.

Our management has broad discretion to use our cash, cash equivalents and investments to fund our operations and could spend these funds in ways that do not improve our results of operations or enhance the value of our common stock. The failure by our management to apply these funds effectively could result in financial losses that could have a material adverse effect on our business, cause the price of our common stock to decline and delay the development of our product candidates. Pending their use to fund our operations, we may invest our cash and cash equivalents in a manner that does not produce income or that loses value.

If we identify a material weakness in our internal control over financial reporting, it could have an adverse effect on our business and financial results and our ability to meet our reporting obligations could be negatively affected, each of which could negatively affect the trading price of our common stock.

A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis. Accordingly, a material weakness increases the risk that the financial information we report contains material errors.

We regularly review and update our internal controls, disclosure controls and procedures, and corporate governance policies. In addition, we are required under the Sarbanes-Oxley Act of 2002 to report annually on our internal control over financial reporting. Any system of internal controls, however well designed and operated, is based in part on certain assumptions and can provide only reasonable, not absolute, assurances that the objectives of the system are met. If we, or our independent registered public accounting

firm, determine that our internal control over our financial reporting is not effective, or we discover areas that need improvement in the future, or we experience high turnover of our personnel in our financial reporting functions, these shortcomings could have an adverse effect on our business and financial results, and the price of our common stock could be negatively affected.

If we cannot conclude that we have effective internal control over our financial reporting, or if our independent registered public accounting firm is unable to provide an unqualified opinion regarding the effectiveness of our internal control over financial reporting,

investors could lose confidence in the reliability of our financial statements, which could lead to a decline in our stock price. Failure to comply with reporting requirements could also subject us to sanctions and/or investigations by the SEC, the Nasdaq Stock Market or other regulatory authorities.

If the estimates we make, or the assumptions on which we rely, in preparing our consolidated financial statements, our projected guidance and/or our projected market opportunities prove inaccurate, our actual results may vary from those reflected in our projections and accruals.

Our consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“~~GAAP��~~GAAP”). The preparation of these consolidated financial statements requires us to make estimates and judgments that affect the reported amounts of our assets, liabilities, revenues and expenses, the amounts of charges accrued by us and related disclosure of contingent assets and liabilities. We base our estimates on historical experience and on various other assumptions that we believe to be reasonable under the circumstances.

We cannot assure you, however, that our estimates, or the assumptions underlying them, will be correct. Further, from time to time we issue financial guidance relating to our expectations regarding our non-GAAP research and development and selling, general and administrative expenses, and expectations for our cash, cash equivalents and investments available for operations, which guidance is based on estimates and the judgment of management. If, for any reason, our expenses differ materially from our guidance or we utilize our cash more quickly than anticipated, we may have to adjust our publicly announced financial guidance. If we fail to meet, or if we are required to change or update any element of, our publicly disclosed financial guidance or other expectations about our business, our stock price could decline.

Further our estimates of the potential market opportunities for XPOVIO and our product candidates include several key assumptions based on our industry knowledge, industry publications, third-party research and other surveys, which may be based on a small sample size and fail to accurately reflect market opportunities. While we believe that our internal assumptions are reasonable, these assumptions involve the exercise of significant judgment on the part of our management, are inherently uncertain and the reasonableness of these assumptions has not been assessed by an independent source. If any of our assumptions or estimates, or these publications, research, surveys or studies prove to be inaccurate, then the actual market for XPOVIO, selinexor or any other products or product candidates may be smaller than we expect, and as a result our product revenue may be limited and it may be more difficult for us to achieve profitability.

Our ability to use our net operating loss carryforwards and tax credit carryforwards to offset future taxable income may be subject to certain limitations.

Under the provisions of the Internal Revenue Code of 1986, as amended (the “Code”), our net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service (and state tax authorities under relevant state tax rules). In addition, as described below in “Changes in tax laws or in their implementation or interpretation may adversely affect our business and financial condition,” the Tax Cuts and Jobs Act of 2017 (the “TCJA”) (as amended by the CARES Act) includes changes to U.S. federal tax rates and the rules governing net operating loss carryforwards that may significantly impact our ability to utilize our net operating losses to offset taxable income in the future. Furthermore, the use of net operating loss and tax credit carryforwards may become subject to an annual limitation under Sections 382 and 383 of the Code, respectively, and similar state provisions in the event of certain cumulative changes in the ownership interest of significant shareholders in excess of 50 percent over a three-year period. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of a company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. Our company has completed several financings since its inception which resulted in an ownership change under Sections 382 and 383 of the Code. In addition, future changes in our stock ownership, some of which are outside of our control, could result in ownership changes in the future. For these reasons, we may not be able to use some or all of our net operating loss and tax credit carryforwards, even if we attain profitability.

Changes in tax laws or in their implementation or interpretation may adversely affect our business and financial condition.

Changes in tax law may adversely affect our business or financial condition. The TCJA, as amended by the CARES Act, significantly revises the Code. The TCJA, among other things, contains significant changes to corporate taxation, including reduction

of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%, limitation of the tax deduction for net interest expense to 30% of adjusted taxable income (except for certain small businesses), limitation of the deduction for net operating losses to 80% of current year taxable income and elimination of net operating loss carrybacks, in each case, for losses arising in taxable years beginning after December 31, 2017 (though any such net operating losses may be carried forward ~~indefinitely)~~indefinitely and such NOLs arising in taxable years beginning after January 1, 2021 are generally eligible to be carried back up to five years), one time taxation of offshore earnings at reduced rates regardless of whether they are repatriated, elimination of U.S. tax on foreign earnings (subject to certain important exceptions),

immediate deductions for certain new investments instead of deductions for depreciation expense over time, and modifying or repealing many business deductions and credits.

AsIn addition to the CARES Act, as part of Congress’ response to the COVID-19 pandemic, ~~the Families First Coronavirus Response Act (the “FFCR Act”) was~~economic relief legislation has been enacted ~~on March 18, 2020, the CARES Act was enacted on March 27, 2020, COVID-19 relief provisions were included~~ in ~~the Consolidated Appropriations Act, 2021 (“CAA”), which was enacted on December 27,~~ 2020 and ~~the American Rescue Plan Act of~~ 2021 ~~(“ARPA”), was enacted on March 11, 2021. All contain numerous~~containing tax provisions. In particular, the CARES Act retroactively and temporarily (for taxable years beginning before January 1, 2021) suspends application of the 80%-of-income limitation on the use of net operating losses, which was enacted as part of the TCJA. It also provides that net operating losses arising in any taxable year beginning after December 31, 2017, and before January 1, 2021 are generally eligible to be carried back up to five years. The CARES Act also temporarily (for taxable years beginning in 2019 or 2020) relaxes the limitation of the tax deductibility for net interest expense by increasing the limitation from 30% to 50% of adjusted taxable income.

Regulatory guidance under the TCJA ~~the FFCR Act, the CARES Act, the CAA~~ and ~~the ARPA~~such additional legislation is and continues to be forthcoming, and such guidance could ultimately increase or lessen their impact on our business and financial condition. ~~It is also likely that Congress will enact additional legislation in connection with the COVID-19 pandemic, and~~Also, as a result of the changes in the U.S. presidential administration and control of the U.S. Senate, additional tax legislation may ~~also~~ be enacted; any such additional legislation could have an impact on us. In addition, it is uncertain if and to what extent various states will conform to the TCJA ~~the FFCR Act, the CARES Act, the CAA or the ARPA.~~and additional tax legislation.

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.


Delaware		26-3931704
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification Number)

85 Wells Avenue, 2nd Floor Newton, MA		02459
(Address of principal executive offices)		(Zip Code)


	PART I - FINANCIAL INFORMATION	43

Item 1.	Condensed Consolidated Financial Statements (Unaudited)	43
	Condensed Consolidated Balance Sheets	43
	Condensed Consolidated Statements of Operations	54
	Condensed Consolidated Statements of Comprehensive Loss	65
	Condensed Consolidated Statements of Cash Flows	76
	Condensed Consolidated Statements of Stockholders’ Equity	87
	Notes to Condensed Consolidated Financial Statements	98
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	19
Item 3.	Quantitative and Qualitative Disclosures About Market Risk	2527
Item 4.	Controls and Procedures	2527

	PART II - OTHER INFORMATION	2628

Item 1.	Legal Proceedings	2628
Item 1A.	Risk Factors	2628
Item 6.	Exhibits	6567
	Signatures	6668


	As of March 31,				As of June 30,
	2021		2020		2021		2020
Outstanding stock options		12,900		11,233		12,804		11,215
Unvested restricted stock units		2,517		1,734		2,723		1,693


Exhibit Number		Description of Exhibit

10.1		Omnibus Amendment to Transaction Documents, dated as of June 23, 2021, by and among the Registrant, Karyopharm Europe GmbH, Karyopharm Therapeutics (Bermuda) Ltd., HealthCare Royalty Partners III, L.P., HealthCare Royalty Partners IV, L.P., HCRP Overflow Fund, L.P., HCR Stafford Fund, L.P., HCR Canary Fund, L.P., HCR Potomac Fund, L.P., HCR Molag Fund, L.P., HealthCare Royalty Management, LLC and HCR Collateral Management, LLC (incorporated by reference to Exhibit 10.1 to the Registrant’s Current Report on Form 8-K (File No. 001-36167) filed with the Commission on June 24, 2021).

10.2*		Non-Employee Director Compensation Policy, dated as of May 12, 2021.

10.3		Offer Letter, dated as of April 28, 2021, between the Company and Richard Paulson (incorporated by reference to Exhibit 10.1 to the Registrant’s Current Report on Form 8-K (File No. 001-36167) filed with the Commission on May 3, 2021).


~~10.2~~10.4		Amended and Restated Letter Agreement, dated as of April 28, 2021, between the Company and Michael Kauffman, M.D., Ph.D. (incorporated by reference to Exhibit 10.2 to the Registrant’s Current Report on Form 8-K (File No. 001-36167) filed with the Commission on May 3, 2021).


~~10.3~~10.5		Amended and Restated Letter Agreement, dated as of April 28, 2021, between the Company and Sharon Shacham, Ph.D., M.B.A. (incorporated by reference to Exhibit 10.3 to the Registrant’s Current Report on Form 8-K (File No. 001-36167) filed with the Commission on May 3, 2021).

31.1*		Certification of principal executive officer pursuant to Rule 13a-14(a)/15d-14(a) of the Securities Exchange Act of 1934, as amended.

31.2*		Certification of principal financial officer pursuant to Rule 13a-14(a)/15d-14(a) of the Securities Exchange Act of 1934, as amended.

32.1**		Certification of principal executive officer pursuant to 18 U.S.C. §1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

32.2**		Certification of principal financial officer pursuant to 18 U.S.C. §1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

101.INS		Inline XBRL Instance Document. The instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document.

101.SCH		Inline XBRL Taxonomy Extension Schema Document.

101.CAL		Inline XBRL Taxonomy Extension Calculation Linkbase Document.

101.DEF		Inline XBRL Taxonomy Extension Definition Linkbase Document.

101.LAB		Inline XBRL Taxonomy Extension Label Linkbase Document.

101.PRE		Inline XBRL Taxonomy Extension Presentation Linkbase Document.

104		Cover Page Interactive Data File (formatted as inline XBRL with applicable taxonomy extension information contained in Exhibits 101)


	KARYOPHARM THERAPEUTICS INC.

Date: ~~May 4,~~August 5, 2021	By:	/s/ RICHARD PAULSON
		Richard Paulson
		President and Chief Executive Officer
		(Principal executive officer)

Date: ~~May 4,~~August 5, 2021	By:	/s/ MICHAEL MASON
		Michael Mason
		~~Senior~~Executive Vice President, Chief Financial Officer and Treasurer
		(Principal financial and accounting officer)


☒	QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934


☐	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934


Large accelerated filer	☒	Accelerated filer	☐

Non-accelerated filer	☐	Smaller reporting company	☐

		Emerging growth company	☐


	Six Months Ended June 30,
	2021			2020			$ Change			% Change
	(in thousands)
Product revenue, net	$	41,910		$	34,662		$	7,248			21	%
License and other revenue		3,951			16,990			(13,039	)		(77	)%
Operating expenses:
Cost of sales		2,071			1,215			856			70	%
Research and development		71,031			76,591			(5,560	)		(7	)%
Selling, general and administrative		74,180			61,521			12,659			21	%
Loss from operations		(101,421	)		(87,675	)		(13,746	)		16	%
Other expense, net		(9,292	)		(11,479	)		2,187			(19	)%
Loss before income taxes		(110,713	)		(99,154	)		(11,559	)		12	%
Income tax provision		(283	)		(203	)		(80	)		39	%
Net loss	$	(110,996	)	$	(99,357	)	$	(11,639	)		12	%