Iovance Biotherapeutics (IOVA) 10-K 27 Feb 25 2024 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2024	Feb. 21, 2025	Jun. 30, 2024
Document And Entity Information
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Document Transition Report	false
Entity File Number	001-36860
Entity Registrant Name	IOVANCE BIOTHERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	75-3254381
Entity Address, Address Line One	825 Industrial Road, Suite 100
Entity Address, City or Town	San Carlos
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94070
City Area Code	650
Local Phone Number	260-7120
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $ 0.000041666 Par Value per Share
Trading Symbol	IOVA
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		327,876,694
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 2.1
Auditor Name	Ernst & Young LLP
Auditor Firm ID	42
Auditor Location	San Mateo, California
Entity Central Index Key	0001425205
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Current Assets
Cash and cash equivalents	$ 115,694	$ 114,888
Trade accounts receivable	69,340	151
Short-term investments	208,087	164,979
Inventory	51,520	10,372
Prepaid expenses and other assets	12,377	17,458
Total Current Assets	457,018	307,848
Property and equipment, net	109,081	114,030
Intangible assets, net	282,398	229,258
Operating lease right-of-use assets	55,201	62,515
Restricted cash	6,359	66,430
Long-term assets	369	270
Total Assets	910,426	780,351
Current Liabilities
Accounts payable	27,509	33,123
Accrued expenses and other liabilities	81,936	69,406
Operating lease liabilities	12,896	7,777
Total Current Liabilities	122,341	110,306
Non-Current Liabilities
Operating lease liabilities - non-current	44,365	67,085
Deferred tax liabilities	32,315	17,347
Long-term note payable	1,000	1,000
Total Non-Current Liabilities	77,680	85,432
Total Liabilities	200,021	195,738
Commitments and contingencies
Stockholders' Equity
Common stock, $0.000041666 par value; 500,000,000 shares authorized, 305,252,194 and 256,135,715 shares issued and outstanding as of December 31, 2024 and December 31, 2023, respectively	13	11
Accumulated other comprehensive loss (income)	(1,046)	2,526
Additional paid-in capital	3,095,987	2,594,448
Accumulated deficit	(2,384,552)	(2,012,375)
Total Stockholders' Equity	710,405	584,613
Total Liabilities and Stockholders' Equity	910,426	780,351
Series A Convertible Preferred Stock
Stockholders' Equity
Preferred stock, Value
Series B Convertible Preferred Stock
Stockholders' Equity
Preferred stock, Value	$ 3	$ 3

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2024	Dec. 31, 2023
Common stock, par or stated value per share	$ 0.000041666	$ 0.000041666
Common stock, shares authorized	500,000,000	500,000,000
Common Stock, Shares, Issued	305,252,194	256,135,715
Common Stock, Shares, Outstanding	305,252,194	256,135,715
Series A Convertible Preferred Stock
Preferred stock, par or stated value per share	$ 0.001	$ 0.001
Preferred stock, shares authorized	17,000	17,000
Preferred Stock, Shares Issued	194	194
Preferred stock, shares outstanding	194	194
Series B Convertible Preferred Stock
Preferred stock, par or stated value per share	$ 0.001	$ 0.001
Preferred stock, shares authorized	11,500,000	11,500,000
Preferred Stock, Shares Issued	2,842,158	2,842,158
Preferred stock, shares outstanding	2,842,158	2,842,158

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Consolidated Statements of Operations
Total net revenue	$ 164,070	$ 1,189
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Costs and expenses
Cost of sales	$ 123,995	$ 10,755
Research and development	282,336	344,077	$ 294,781
Selling, general and administrative	153,017	106,916	104,097
Total costs and expenses	559,348	461,748	398,878
Loss from operations	(395,278)	(460,559)	(398,878)
Other income
Interest and other income, net	20,273	13,043	2,985
Net Loss before income taxes	(375,005)	(447,516)	(395,893)
Income tax benefit	2,828	3,479	0
Net Loss	$ (372,177)	$ (444,037)	$ (395,893)
Net Loss Per Share of Common Stock, Basic	$ (1.28)	$ (1.89)	$ (2.49)
Net Loss Per Share of Common Stock, Diluted	$ (1.28)	$ (1.89)	$ (2.49)
Weighted Average Shares of Common Stock Outstanding, Basic	289,877	235,131	159,259
Weighted Average Shares of Common Stock Outstanding, Diluted	289,877	235,131	159,259

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Consolidated Statements of Comprehensive Loss
Net Loss	$ (372,177)	$ (444,037)	$ (395,893)
Other comprehensive loss:
Unrealized gain on investments	78	940	(301)
Foreign currency translation adjustment	(3,650)	2,488
Comprehensive Loss	$ (375,749)	$ (440,609)	$ (396,194)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Series A Convertible Preferred Stock Preferred Stock	Series B Convertible Preferred Stock Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Total
Beginning Balance at Dec. 31, 2021		$ 3	$ 7	$ 1,794,695	$ (601)	$ (1,172,445)	$ 621,659
Beginning Balance (in Shares) at Dec. 31, 2021	194	2,842,158	157,004,742
Stock-based compensation expense				84,022			84,022
Common stock issued upon purchase of employee stock purchase plan				1,655			1,655
Common stock issued upon purchase of employee stock purchase plan (in shares)			262,701
Vesting of restricted shares issued for services (in shares)			894,760
Tax payments related to shares retired for vested restricted stock units				(2,649)			(2,649)
Tax payments related to shares retired for vested restricted stock units (in shares)			(342,703)
Common stock sold in public and/or at the market offering, net of offering costs			$ 1	189,501			189,502
Common stock sold in public and/or at the market offering, net of offering costs (in shares)			29,788,993
Common stock issued upon exercise of stock options				1,642			1,642
Common stock issued upon exercise of stock options (in shares)			203,579
Unrealized gain on investments					(301)		(301)
Net Income (Loss)						(395,893)	(395,893)
Ending Balance at Dec. 31, 2022		$ 3	$ 8	2,068,867	(902)	(1,568,338)	499,638
Ending Balance (in Shares) at Dec. 31, 2022	194	2,842,158	187,812,072
Stock-based compensation expense				62,625			62,625
Common stock issued upon purchase of employee stock purchase plan				2,410			2,410
Common stock issued upon purchase of employee stock purchase plan (in shares)			435,459
Vesting of restricted shares issued for services (in shares)			1,253,465
Tax payments related to shares retired for vested restricted stock units				(2,795)			(2,795)
Tax payments related to shares retired for vested restricted stock units (in shares)			(454,367)
Common stock sold in public and/or at the market offering, net of offering costs			$ 3	463,278			463,281
Common stock sold in public and/or at the market offering, net of offering costs (in shares)			67,080,226
Common stock issued upon exercise of stock options				63			63
Common stock issued upon exercise of stock options (in shares)			8,860
Unrealized gain on investments					940		940
Foreign currency cumulative translation adjustment					2,488		2,488
Net Income (Loss)						(444,037)	(444,037)
Ending Balance at Dec. 31, 2023		$ 3	$ 11	2,594,448	2,526	(2,012,375)	584,613
Ending Balance (in Shares) at Dec. 31, 2023	194	2,842,158	256,135,715
Stock-based compensation expense				110,877			110,877
Common stock issued upon purchase of employee stock purchase plan				2,952			2,952
Common stock issued upon purchase of employee stock purchase plan (in shares)			497,044
Vesting of restricted shares issued for services (in shares)			3,150,172
Tax payments related to shares retired for vested restricted stock units				(12,858)			(12,858)
Tax payments related to shares retired for vested restricted stock units (in shares)			(1,098,388)
Common stock sold in public and/or at the market offering, net of offering costs			$ 2	397,302			397,304
Common stock sold in public and/or at the market offering, net of offering costs (in shares)			46,141,726
Common stock issued upon exercise of stock options				3,266			3,266
Common stock issued upon exercise of stock options (in shares)			425,925
Unrealized gain on investments					78		78
Foreign currency cumulative translation adjustment					(3,650)		(3,650)
Net Income (Loss)						(372,177)	(372,177)
Ending Balance at Dec. 31, 2024		$ 3	$ 13	$ 3,095,987	$ (1,046)	$ (2,384,552)	$ 710,405
Ending Balance (in Shares) at Dec. 31, 2024	194	2,842,158	305,252,194

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash Flows from Operating Activities
Net Income (Loss)	$ (372,177)	$ (444,037)	$ (395,893)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	109,627	62,625	84,022
Unrealized foreign exchange gains	(175)	70
Amortization of intangible assets	21,202	9,849
Amortization of right of use asset	10,437	11,710	11,825
Depreciation and amortization of property and equipment	11,967	11,568	9,310
Deferred tax benefit	(2,828)	(3,479)
Accretion of discounts and premiums on investments	(10,261)	(3,605)	474
Impairment of long-lived assets	7,355		397
Gain on derecognition of lease assets and liabilities	(5,568)
Changes in assets and liabilities:
Prepaid expenses, other assets and long-term assets	(2,113)	(10,062)	(2,130)
Trade accounts receivable	(69,189)	(149)
Inventory	(39,917)	(10,118)
Operating lease liabilities	(12,074)	(10,794)	(1,942)
Accounts payable	(7,841)	4,828	5,883
Accrued expenses and other liabilities	8,578	19,774	(4,703)
Net cash used in operating activities	(352,977)	(361,820)	(292,757)
Cash Flows from Investing Activities
Maturities of investments	428,000	285,583	522,696
Purchase of investments	(460,769)	(205,902)	(245,816)
Cash paid for acquisition, including contingent consideration, net of cash acquired	(52,573)	(212,633)
Purchase of property and equipment	(11,069)	(22,290)	(20,425)
Net cash used in investing activities	(96,411)	(155,242)	256,455
Cash Flows from Financing Activities
Tax payments related to shares withheld for vested restricted stock units	(12,858)	(2,795)	(2,649)
Proceeds from the issuance of common stock under employee stock purchase plan	2,952	2,410	1,655
Proceeds from the issuance of common stock upon exercise of options	3,266	63	1,642
Proceeds from the issuance of common stock, net	397,304	463,281	189,502
Net cash provided by financing activities	390,664	462,959	190,150
Effect of foreign exchange rate changes	(541)	(2,740)
Net increase in cash, cash equivalents and restricted cash	(59,265)	(56,843)	153,848
Cash, Cash Equivalents and Restricted Cash Beginning of Period	181,318	238,161	84,313
Cash, Cash Equivalents and Restricted Cash End of Period	122,053	181,318	238,161
Supplemental disclosure of non-cash investing and financing activities:
Fair value of net assets acquired		222,637
Net unrealized gain on investments	78	940	(301)
Acquisition of property and equipment included in accounts payable and accrued expenses	7,365	4,062	5,985
Intangible asset and deferred tax liability arising from contingent consideration	17,495
Lease liabilities arising from obtaining right-of-use asset from new leases	2,306	177	553
Lease liabilities arising from obtaining right-of-use asset from lease modifications	$ (7,833)	$ 1,033	$ 15,304

GENERAL ORGANIZATION, BUSINESS

GENERAL ORGANIZATION, BUSINESS AND LIQUIDITY	12 Months Ended
	Dec. 31, 2024
GENERAL ORGANIZATION, BUSINESS AND LIQUIDITY
GENERAL ORGANIZATION, BUSINESS AND LIQUIDITY	NOTE 1. GENERAL ORGANIZATION, BUSINESS AND LIQUIDITY General Organization and Business Iovance Biotherapeutics, Inc. (the “Company”) is a commercial-stage biopharmaceutical company pioneering a transformational approach to treating cancer by harnessing the human immune system’s ability to recognize and destroy diverse cancer cells using therapies personalized for each patient. The Company’s mission is to be the global leader in innovating, developing, and delivering tumor infiltrating lymphocyte (“TIL”) cell therapies for patients with solid tumor cancers. The Company is executing the U.S. launch of Amtagvi ® ® ® ® ® ® ® Beyond the U.S., the Company plans to launch Amtagvi ® ® The Company was founded to build upon the promise of TIL cell therapy that was previously demonstrated in single-center clinical trials at academic research centers, including the National Cancer Institute (“NCI”). The Company’s multi-center trials, novel TIL products, manufacturing processes, facilities, and bioanalytical platforms have transformed TIL cell therapy into a commercially viable treatment which thousands of patients with cancer can access. The Company manufactures Amtagvi ® ® i The Company’s development pipeline includes multicenter trials of TIL cell therapies in additional treatment settings and indications for solid tumor cancers. To potentially improve outcomes for patients, the Company is investigating TIL monotherapies for patients previously treated with standard of care therapies and TIL cell therapy in combination with standard of care therapies for patients in earlier treatment settings. The Company is conducting two ongoing registrational trials to support a supplementary BLA (“sBLA”), of lifileucel in frontline advanced melanoma and in advanced non-small cell lung cancer (“NSCLC”) following standard of care chemo-immunotherapy. The Company is also developing next generation therapies, such as genetically modified TIL cell therapy and next generation cytokines for use in the TIL cell therapy regimen. Liquidity As of December 31, 2024, the Company had $330.1 million in cash, cash equivalents, short term-investments, and restricted cash ($115.7 million of cash and cash equivalents, $208.1 million in short-term investments, and $6.4 million in restricted cash). The Company has recently launched its first internally developed commercial product and continues to be engaged in the development of therapeutics to fight cancer, specifically solid tumors. With the recent approval of the BLA, the Company began to generate revenue from the sale of its product Amtagvi ® ® ® ® ® ® positive operational cash flows during the 12 months from the date the consolidated financial statements are issued and this Form 10-K is filed. The Company has incurred a net loss of $372.2 million for the year ended December 31, 2024 and used $353.0 million of cash in its operating activities during the year ended December 31, 2024. ​ The Company expects to continue to incur significant expenses to support its execution of the commercial launch of Amtagvi ® ​ Concentrations of Risk The Company is subject to credit risk from its portfolio of cash, cash equivalents, trade accounts receivable and investments. Under its investment policy, the Company limits amounts invested in securities by credit rating, maturity, industry group, investment type and issuer, except for securities issued by the U.S. government. The Company does not believe it is exposed to any significant concentrations of credit risk from these financial instruments. The goals of its investment policy are safety and preservation of principal, diversification of risk, and liquidity of investments sufficient to meet cash flow requirements. ​

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES	12 Months Ended
	Dec. 31, 2024
SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES
SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES	NOTE 2. SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES Cash, Cash Equivalents, and Investments The Company’s cash and cash equivalents include short-term investments with original maturities of three months or less when purchased. The Company's investments are classified as “available-for-sale.” The Company includes these investments in current assets or non-current assets in the Consolidated Balance Sheets based on the length of maturity from the reporting date and carries them at fair value. Unrealized gains and losses on available-for-sale securities are recorded in accumulated other comprehensive loss. Impairment losses related to credit losses (if any) are recorded as an allowance for credit losses with an offsetting entry to Interest income, net. No impairment losses related to credit losses were recognized for the years ended December 31, 2024, 2023 and 2022. The cost of debt securities is adjusted for the amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in Interest income, net in the consolidated statements of operations. Gains and losses on securities sold are recorded based on the specific identification method and are included in Interest income, net in the consolidated statements of operations. The Company has not incurred any realized gains or losses from sales of securities to date. The Company’s investment policy limits investments to certain types of instruments such as certificates of deposit, money market instruments, obligations issued by the U.S. government and U.S. government agencies as well as corporate debt securities and commercial paper, and places restrictions on maturities and concentration by type and issuer, except for securities issued by the U.S. government. Restricted Cash As of December 31, 2024 and December 31, 2023, restricted cash totaled $6.4 million and $66.4 million, respectively. These amounts have been classified as either current or non-current assets in the Company’s consolidated balance sheet based on the maturity date of the underlying letter of credit agreement. The Company maintains a required minimum balance in segregated bank accounts in connection with its letters of credit for which amounts are restricted as to their use by the Company. As of December 31, 2024, the Company’s letters of credit were primarily comprised of a letter of credit for the benefit of the i A letter of credit in the amount of $60.0 million for the regulatory approval milestone payment as required by the terms of the Option Agreement for the Proleukin ® ® The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ 2024 ​ 2023 ​ 2022 Cash and cash equivalents ​ $ 115,694 ​ $ 114,888 ​ $ 231,731 Restricted cash ​ 6,359 ​ 66,430 ​ 6,430 Total cash, cash equivalents and restricted cash ​ $ 122,053 ​ $ 181,318 ​ $ 238,161 ​ Asset Acquisitions ​ The Company evaluates acquisitions of assets using the guidance in Accounting Standard Codification (“ASC”) Topic 805, Business Combinations (“ASC 805”), to determine whether the transaction should be accounted for as a business combination or asset acquisition by first applying a screen test to assess if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of assets. If the screen test is met, the transaction is accounted for as an asset acquisition. If the screen test is not met, further assessment is required to determine whether the Company has acquired inputs and processes that have the ability to create outputs, which would meet the requirements of a business. If the assets acquired do not constitute a business, the Company accounts for asset acquisitions using the cost accumulation and allocation method. Under this method, the cost of the acquisition, including direct acquisition-related costs, is allocated to the assets acquired on a relative fair value basis. Goodwill is not recognized in an asset acquisition and any difference between consideration transferred and the fair value of the net assets acquired is allocated to the identifiable assets acquired based on their relative fair values. Deferred tax liabilities arising from basis differences in assets acquired are calculated using the simultaneous equations method under ASC Topic 740, Income Taxes (“ASC 740”), and based on the effective tax rate. The resulting deferred tax liability is recorded in the consolidated balance sheet as of December 31, 2024. Contingent consideration in the scope of ASC Topic 815, Derivatives and Hedging (“ASC 815”), is included in the cost of the asset acquisition at its acquisition date fair value. Contingent consideration in the scope of ASC Topic 450, Contingencies (“ASC 450”), is recognized when it is both probable and reasonably estimable. Inventory and Cost of Sales ​ Inventory is stated at the lower of cost or net realizable value on a first-in, first-out basis. Cost includes amounts related to materials, internal labor, costs of external manufacturing, and allocable depreciation of manufacturing facilities, equipment and overhead. Net realizable value is the estimated selling price in the ordinary course of business less reasonably predictable costs of completion, disposal and transportation. Inventoriable c osts incurred, such as manufacturing costs incurred prior to regulatory approval that did not qualify for capitalization and clinical manufacturing costs, are expensed as incurred as research and development expenses. Upon the February 2024 approval of Amtagvi ® ® Proleukin ® ® The Company periodically reviews inventory for excess and obsolescence, considering factors such as its most recent sales forecast compared to quantities on hand and the expiration date of the product and materials. The Company adjusts its inventory that is obsolete or otherwise unmarketable to its estimated net realizable value in the period in which the impairment is first identified. Any such adjustments are included as a component of cost of sales within the Company’s consolidated statements of operations. Cost of sales includes inventory and period costs related to overhead and manufacturing costs of Amtagvi ® ® ® During the Company’s commercial manufacturing process, certain Amtagvi ® Trade Accounts Receivable ​ Trade accounts receivable are recorded net of allowances for product returns and estimated credit losses. The estimate of allowance for credit losses considers factors, including existing contractual payment and the aging of receivable from its customers. To date, the Company has determined that an allowance for credit losses is not required. ​ Intangible Assets ​ The Company’s intangible assets are initially measured based on an allocation of the cost of the acquisition to the assets acquired on a relative fair value basis and are recorded net of accumulated amortization. The Company amortizes the intangible assets on a straight-line basis over their estimated useful lives. When contingent consideration is a component of the cost of an asset acquisition, the Company capitalizes the amount of incremental cost from the contingent consideration related to the intangible asset acquired in the period the underlying contingency is resolved. When this occurs, the Company will recognize amortization expense on the incremental cost prospectively from the date the incremental costs are capitalized. The Company reviews intangible assets for impairment at least annually and whenever events or changes in circumstances have occurred which could indicate that the carrying value of the assets are not recoverable. If such indicators are present, the Company assesses the recoverability of affected assets by determining if the carrying value of the assets is less than the sum of the undiscounted future cash flows of the assets. If the assets are found to not be recoverable, the Company measures the amount of impairment by comparing the carrying value of the assets to their fair values. The Company determined that no indicators of impairment existed as of December 31, 2024. Leases The Company determines if an arrangement includes a lease at inception and thereafter, if modified. Operating leases are included in its consolidated balance sheets as Operating lease right-of-use assets and Operating lease liabilities as of December 31, 2024 and 2023. Operating lease right-of-use assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date or modification date based on the present value of lease payments over the lease term. In determining the net present value of lease payments, the Company uses an estimated incremental borrowing rate that is applicable to the Company based on the information available at the later of the lease commencement or modification date. The operating lease right-of-use assets also include any lease payments made less lease incentives. The Company’s leases may include options to extend or terminate the lease, which is considered in the lease term when it is reasonably certain that the Company will exercise any such options. Lease expense is recognized on a straight-line basis over the expected lease term and recorded in costs and expenses in the consolidated statements of operations. The Company has elected not to apply the recognition requirements of Accounting Standards Update (“ASU”) No. 2016-02 and No. 2018-10 (together “Topic 842”) for short-term leases. For lease agreements entered into by the Company that include lease and non-lease components, such components are generally accounted for separately. Property and Equipment, net ​ Property and equipment are stated at cost, net of accumulated depreciation and amortization. The cost of property and equipment is depreciated or amortized on the straight-line method over the following estimated useful lives. The depreciation or amortization of capitalized construction in progress costs, a component of property and equipment, net, begins once the underlying asset is placed into service and is recognized over the estimated useful lives: ​ Computer equipment 2 years Computer software ​ 5 years Office furniture and equipment ​ 5 years Lab, process, and validation equipment ​ 5 years Machinery and equipment ​ 5 – 7 years Utility equipment ​ Lesser of the remaining economic life of the asset or the lease-term Leasehold improvements ​ Lesser of the remaining economic life of the asset or the lease-term ​ Expenditures for maintenance and repairs are charged to operations as incurred while renewals and betterments are capitalized. Gains and losses on disposals are included within operating expenses in the consolidated statements of operations. Management assesses the carrying value of property and equipment whenever events or changes in circumstances indicate that the carrying value may not be recoverable. If there is an indication of impairment, management prepares an estimate of future undiscounted cash flows expected to result from the use of the asset and its eventual disposition. If these cash flows are less than the carrying amount of the asset, an impairment loss is recognized to write down the asset to its estimated fair value. For the years ended December 31, 2024, 2023, and 2022, the Company did not recognize any impairments for its property and equipment. ​ Fair Value Measurements Under ASC Topic 820, Fair Value Measurements and Disclosures (“ASC 820”), fair value is defined as the price at which an asset could be exchanged, or a liability transferred in a transaction between knowledgeable, willing parties in the principal or most advantageous market for the asset or liability. Where available, fair value is based on observable market prices or parameters or derived from such prices or parameters. Where observable prices or parameters are not available, valuation models are applied. Assets and liabilities recorded at fair value in the Company’s financial statements are categorized based upon the level of judgment associated with the inputs used to measure their fair value. Hierarchical levels directly related to the amount of subjectivity associated with the inputs to fair valuation of these assets and liabilities, are as follows: - Level 1—These are investments where values are based on unadjusted quoted prices for identical assets in an active market that the Company has the ability to access. - Level 2—These are investments where values are based on quoted market prices in markets that are not active or model derived valuations in which all significant inputs are observable in active markets. - Level 3—These are financial instruments where values are derived from techniques in which one or more significant inputs are unobservable. The Company’s financial instruments consist of cash, cash equivalents, short-term investments, and long-term notes payable, all of which are reported at their respective fair value or approximate fair value on its consolidated balance sheets. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Where quoted prices are available in an active market, securities are classified as Level 1. ​ When quoted market prices are not available for a specific security, the Company estimates the fair value by using quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs obtained from various third-party data providers, including but not limited to, benchmark yields, interest rate curves, reported trades, broker/dealer quotes, and market reference data. ​ Revenue Recognition The Company recognizes revenue from product sales in accordance with ASC Topic 606, Revenue from Contracts with Customers In the U.S., products are sold principally to hospitals and clinics, as well as distributors and wholesalers, and outside of the U.S. to hospitals and clinics. Contractual performance obligations are usually limited to transfer of control of the product to the customer. In the case of Amtagvi ® ® Revenue is reduced at the time of recognition for expected chargebacks, product returns, discounts, rebates, and sales allowances, collectively referred to as gross to net adjustments (“GTN adjustments”). In the U.S., these GTN adjustments are attributable to various commercial arrangements and government programs. In addition, non-U.S. government programs include different pricing schemes such as cost caps and volume discounts. Cash discounts are recorded as a reduction to receivables and settled through the issuance of credits, typically within one month. All other GTN adjustments are recorded as a liability and settled through cash payments to the customer. Significant judgment is required in estimating GTN adjustments considering legal interpretations of applicable laws and regulations, historical experience, payer channel mix, current contract prices under applicable programs, processing time lags and inventory levels in the distribution channel. Indirect taxes collected from customers and remitted to government authorities that are related to sales of the Company’s products, primarily in Europe, are excluded from revenues. Stock-Based Compensation The Company periodically grants stock options to employees and non-employees as compensation for services rendered. The Company accounts for all stock-based payment awards made to employees, including the employee stock purchase plans, and non-employees in accordance with the authoritative guidance provided by the Financial Accounting Standards Board (“FASB”) where the value of the award is measured on the date of grant and recognized over the vesting period. Forfeitures are recognized in the period in which they occur. The Company accounts for stock option grants to non-employees in a similar manner as stock option grants to employees except for the term used in the grant date fair value, therefore no longer requiring a re-measurement at the then-current fair values at each reporting date until the shares underlying the options have vested. The non-employee awards that contain a performance condition that affects the quantity or other terms of the award are measured based on the outcome that is probable. The fair value of the Company's common stock option grants is estimated using a Black-Scholes option pricing model, which uses certain assumptions related to risk-free interest rates, expected volatility, expected term of the common stock options, and future dividends. The stock-based compensation expense is recorded based upon the value derived from the Black-Scholes option pricing model. The assumptions used in the Black-Scholes option pricing model could affect compensation expense recorded in future periods. The Company issues restricted stock units (“RSUs”) from time to time as part of its equity incentive plans. The Company measures the compensation cost with respect to RSUs issued to employees based upon the estimated fair value of the equity instruments at the date of the grant, which is recognized as an expense over the period during which an employee is required to provide services in exchange for the awards. The fair value of RSUs is based on the closing price of the Company’s common stock on the grant date. In addition to RSUs that have time-based vesting requirements, from time to time the Company may issue RSUs that include certain performance vesting criteria based upon the satisfaction of stated objectives (“PRSUs”). The Company measures the compensation cost with respect to PRSUs issued to employees based upon the estimated fair value of the equity instruments at the date of grant, which is recognized as an expense over the period that achievement is determined to be probable through the stated service period associated with the award. Accrued Research and Development Costs Research and development costs are expensed as incurred. Clinical development costs compose a significant component of research and development costs. The Company has a history of contracting with third parties, including contract research organizations (“CROs”), independent clinical investigators, and contract manufacturing organizations (“CMOs”) that perform various clinical trial activities on the Company’s behalf in connection with the ongoing development of the Company’s product candidates. The financial terms of these contracts are subject to negotiations and may vary from contract to contract and may result in uneven payment flow. The Company accrues and expenses costs for clinical trial activities performed by third parties based upon the work completed to date for each clinical trial in accordance with agreements established with CROs, hospitals, and clinical investigators. Accruals for CROs and CMOs are recorded based on services received and efforts expended pursuant to agreements established with CROs, CMOs and other outside service providers. The Company determines its costs through discussions with internal clinical stakeholders and outside service providers as to the progress or stage of completion of clinical trials or services and the contracted fee to be paid for such services. ​ Included in the Company’s clinical development costs are investigator costs, which are costs associated with treatments administered at clinical sites as required under each clinical trial protocol. The Company’s determination of clinical investigator costs and related timing of expense recognition will depend on a number of factors that include, but are not limited to, (i) the overall number of patients that enroll in the trial at each individual site, (ii) the length of clinical trial enrollment period, (iii) discontinuation and completion rates of patients, (iv) duration of patient safety follow-ups, (v) the number of sites included in the clinical trial, and (vi) the contracted fee of each participating site for patient treatment while on clinical trial, which can vary greatly for several reasons including, but not limited to, geographic region, medical center or physician costs, and overhead costs. In addition, the Company’s estimates for per patient trial costs will vary based on a number of factors that include, but are not limited to, the extent of additional procedures that may be administered by investigators as a result of patient health status, recoverability of patient costs through insurance carriers of patients, and unanticipated cost of injuries incurred as a result of the clinical trial treatment. The Company accrues estimated expenses resulting from obligations under investigator site agreements as the timing of payments does not always timely align with the periods over which the treatments are administered by the clinical investigators. These estimates are typically based on contracted amounts, patient visit data, discussions with internal clinical stakeholders and outside service providers, and historical look-back analysis of actual payments made to date. ​ The Company makes judgements and estimates in determining the accrual balance in each reporting period. ​ In the event advance payments are made to a CRO, CMO or other outside service provider, the payments are recorded within prepaid expenses and other current assets in the Consolidated Balance Sheets and subsequently recognized as research and development expense in the consolidated statements of operations when the associated services have been performed. As actual costs become known, the Company adjusts its estimates, liabilities and assets. Inputs used in the determination of estimates discussed above may vary from actual, which will result in adjustments to research and development expense in future periods. ​ Selling, general, and administrative expense ​ Selling, general, and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in executive, finance, procurement, legal, investor relations, facilities, business development, marketing, commercial, information technology and human resources functions. Other significant costs include facility costs not otherwise included in research and development expenses. Selling, general, and administrative costs are expensed as incurred, and the Company accrues for services provided by third parties related to such expenses by monitoring the status of services provided and receiving estimates from its service providers and adjusting its accruals as actual costs become known. Income Taxes The Company accounts for income taxes using the asset and liability method whereby deferred tax assets and liabilities are recognized for the differences between the carrying amounts of existing assets and liabilities for financial reporting purposes and their respective tax bases. In addition, deferred tax assets are recorded for the future benefit of utilizing net operating losses and research and development credit carryforwards. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of changes in tax laws and rates on deferred tax assets and liabilities is recognized in income in the period of enactment. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company is required to use significant judgment in determining any valuation allowance recorded against its deferred tax assets. In assessing the need for a valuation allowance, the Company considers all available evidence, including scheduled reversal of deferred tax liabilities, past operating results, the feasibility of tax planning strategies and estimates of future taxable income. The Company bases its estimates of future taxable income on assumptions that are consistent with its operating plans, and such assumptions represent its best estimates and involve inherent uncertainties and the application of judgment. Should actual amounts differ from estimates, the amount of tax expense and liabilities recognized could be materially impacted. The Company recognizes the tax benefit from an uncertain tax position if it is more likely than not that the tax position will be sustained upon examination by the tax authorities, based on the merits of the position. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties incurred in relation to the unrecognized tax benefits. Net Loss per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of shares of common stock outstanding and the dilutive common stock equivalent outstanding during the period. The Company’s potentially dilutive common stock equivalent shares, which include incremental common shares issuable upon (i) the exercise of outstanding stock options, (ii) purchases through the 2020 Employee Stock Purchase Plan (the “2020 ESPP”), (iii) vesting of restricted stock units, and (vi) conversion of preferred stock, are only included in the calculation of diluted net loss per share when their effect is dilutive. As of December 31, 2024, 2023, and 2022, the following outstanding common stock equivalents have been excluded from the calculation of net loss per share because their impact would be anti-dilutive. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2024 2023 2022 Stock options ​ 18,218,126 18,899,849 15,240,197 Restricted stock units ​ 9,547,643 ​ 296,751 ​ 260,859 Employee Stock Purchase Plan ​ 239,366 ​ 3,453,901 ​ 2,436,764 Series A Convertible Preferred Stock* ​ 97,000 ​ 97,000 ​ 97,000 Series B Convertible Preferred Stock* ​ 2,842,158 2,842,158 2,842,158 ​ ​ 30,944,293 25,589,659 20,876,978 *on an as-converted basis The dilutive effect of potentially dilutive securities would be reflected in diluted earnings per common share by application of the treasury stock method. Under the treasury stock method, an increase in the fair market value of the Company's common stock could result in a greater dilutive effect from potentially dilutive securities. ​ Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant items subject to such estimates and assumptions include assumptions made in the fair value of intangible assets, inventories acquired as part of the acquisition of Proleukin ® , equity awards and related stock-based compensation, assumptions used in measuring operating right- of-use assets and operating lease liabilities, accounting for potential liabilities, including estimates inherent in accruals related to clinical trials, and the realizability of the Company’s deferred tax assets . Principles of Consolidation The accompanying consolidated financial statements include the accounts of Iovance Biotherapeutics, Inc. and its wholly-owned subsidiaries, Iovance Biotherapeutics Manufacturing LLC, Iovance Biotherapeutics GmbH, Iovance Biotherapeutics B.V ., Iovance Biotherapeutics UK Ltd, Iovance Biotherapeutics UK SP Ltd, Iovance Biotherapeutics Canada, Inc., and Iovance Australia Pty Ltd. All intercompany accounts and transactions have been eliminated. Foreign Currency Translation The consolidated financial statements are presented in U.S. dollars, which is the Company’s reporting currency. The assets and liabilities of the Company’s subsidiaries whose functional currencies are not in U.S. dollars are translated into U.S. dollars at the related period-end exchange rate. The U.S. dollar effects that arise from translation of net assets of these subsidiaries at changing rates are recognized in accumulated other comprehensive loss in the consolidated balance sheets. The subsidiaries’ net loss is translated into U.S. dollars by using the average exchange rate for the applicable period. Segment Reporting The Company operates in one segment, focused on innovating, developing, and commercializing therapies using autologous TIL for patients with solid tumor cancers. Refer to Note 11 to the consolidated financial statements included in this Annual Report on Form 10-K for details. Concentrations The Company is subject to credit risk from its portfolio of cash, cash equivalents and investments. Under its investment policy, the Company limits amounts invested in such securities by credit rating, maturity, industry group, investment type and issuer, except for securities issued by the U.S. government. The Company does not believe it is exposed to any significant concentrations of credit risk from these financial instruments. The Company maintains cash, cash equivalents and investment balances at three financial institutions. Management believes that the financial institutions which hold its cash are financially sound and, accordingly, minimal credit risk exists. As of December 31, 2024 and 2023, respectively, the Company’s cash balances were in excess of insured limits maintained at the financial institutions. Recent Accounting Standards In November 2023, FASB issued Accounting Standard Update (“ASU”) ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which enhances the disclosures required for operating segments in annual and interim consolidated financial statements. ASU 2023-07 was effective for us in our annual reporting starting in fiscal year 2024 and for interim period reporting beginning in fiscal year 2025 on a retrospective basis. The Company adopted ASU 2023-07 as of December 31, 2024, and the enhanced disclosures as required are included in Note 11 – Segments. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires public entities, on an annual basis, to provide disclosure of specific categories in the rate reconciliation, as well as disclosure of income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024 on a prospective basis. Early adoption and retrospective reporting are permitted. The Company is currently evaluating the impact of ASU 2023-09 on its consolidated financial statements. In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which requires the disaggregation of certain expense captions into specified categories in disclosures within the notes to the financial statements to provide enhanced transparency into the expense captions presented on the face of the income statement. ASU 2024-03 is effective for annual reporting periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027, with early adoption permitted, and may be applied either prospectively or retrospectively to financial statements issued for reporting periods after the effective date of ASU 2024-03 or retrospectively to any or all prior periods presented in the financial statements. The Company is currently evaluating the impact of adopting ASU 2024-03.

CASH EQUIVALENTS AND INVESTMENT

CASH EQUIVALENTS AND INVESTMENTS	12 Months Ended
	Dec. 31, 2024
CASH EQUIVALENTS AND INVESTMENTS
CASH EQUIVALENTS AND INVESTMENTS	NOTE 3. CASH EQUIVALENTS AND INVESTMENTS The amortized cost and fair value of cash equivalents and investments as of December 31, 2024 and December 31, 2023 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ As of December 31, 2024 Cost Gains Losses Fair Value U.S. treasury securities ​ $ 207,970 ​ $ 117 ​ $ — ​ $ 208,087 Money market funds ​ ​ 61,432 ​ ​ — ​ ​ — ​ ​ 61,432 Total investments ​ $ 269,402 ​ $ 117 ​ $ — ​ $ 269,519 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ As of December 31, 2023 Cost Gains Losses Fair Value U.S. treasury securities ​ $ 164,940 ​ $ 39 ​ $ — ​ $ 164,979 Money market funds ​ ​ 34,053 ​ ​ — ​ ​ — ​ ​ 34,053 Total investments ​ $ 198,993 ​ $ 39 ​ $ — ​ $ 199,032 ​ The fair value of cash equivalents and investments as of December 31, 2024 and December 31, 2023 are classified as follows in the Company’s consolidated balance sheets (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, Classified as: ​ 2024 2023 Cash equivalents ​ $ 61,432 ​ $ 34,053 Short-term investments ​ ​ 208,087 ​ ​ 164,979 Total investments ​ $ 269,519 ​ $ 199,032 ​ Cash equivalents in the tables above exclude cash demand deposits of $54.3 million and $80.8 million as of December 31, 2024 and 2023, respectively. Unrealized gains and losses are included in accumulated other comprehensive loss, and as of December 31, 2024 and 2023 no unrealized losses on available-for-sale securities have resulted from credit risk. All available-for-sale securities held as of December 31, 2024 and December 31, 2023 had contractual maturities of less than one year. No significant available-for-sale securities held as of the periods presented have been in a continuous unrealized loss position for more than 12 months. To date, the Company has not recorded any impairment charges on its investments. ​ Recurring Fair Value Measurements ​ As of December 31, 2024 and 2023, the fair value of the Company’s financial assets that are measured at fair value on a recurring basis, which consist of cash equivalents and short-term and long-term investments classified as available-for-sale securities, are categorized in the table below based upon the lowest level of significant input to the valuations (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets at Fair Value as of December 31, 2024 ​ Level 1 Level 2 Level 3 Total U.S. treasury securities ​ $ 208,087 ​ $ — ​ $ — ​ $ 208,087 Money market funds ​ ​ 61,432 ​ ​ — ​ ​ — ​ ​ 61,432 Total investments ​ $ 269,519 ​ $ — ​ $ — ​ $ 269,519 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets at Fair Value as of December 31, 2023 ​ Level 1 Level 2 Level 3 Total U.S. treasury securities ​ $ 164,979 ​ $ — ​ $ — ​ $ 164,979 Money market funds ​ ​ 34,053 ​ ​ — ​ ​ — ​ ​ 34,053 Total ​ $ 199,032 ​ $ — ​ $ — ​ $ 199,032 ​

PROLEUKIN ACQUISITION

PROLEUKIN ACQUISITION	12 Months Ended
	Dec. 31, 2024
PROLEUKIN ACQUISITION
PROLEUKIN ACQUISITION	NOTE 4. PROLEUKIN ® ACQUISITION On January 23, 2023, the Company and its newly formed, wholly owned subsidiary, Iovance Biotherapeutics UK Ltd (the “Purchaser”) entered into an Option Agreement (the “Option Agreement”) with Clinigen Holdings Limited, Clinigen Healthcare Limited, and Clinigen, Inc. (collectively “Clinigen”), a global pharmaceutical services company, pursuant to which the Purchaser would acquire the worldwide rights for the manufacturing, supply, commercialization and sale of Proleukin ® ​ On May 18, 2023, the Company completed the Acquisition and specifically acquired (i) all issued and outstanding shares of Clinigen SP Limited (the “Target”), (ii) the business of the Target and Clinigen (the “Proleukin ® ​ The Acquisition was accounted for as an asset acquisition because substantially all of the fair value of the acquired assets was concentrated in the acquired developed technology related to the intellectual property rights of Proleukin ® ® ​ The following table summarizes the total cash consideration and allocated acquisition date fair values of assets acquired and liabilities assumed at the time of the acquisition (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ Amounts Cash ​ $ 35 Inventory ​ ​ 9,688 Developed technology ​ ​ 232,665 Assembled workforce ​ ​ 636 Deferred tax liability ​ ​ (20,352) Total Cost of Acquisition ​ $ 222,672 ​ The $222.7 million of total cost of the Acquisition consisted of (i) a $210.2 million of cash payment to Clinigen and (ii) $12.5 million of direct transaction costs incurred by the Company. The Option Agreement additionally provides for contingent cash payments consisting of (i) a milestone payment of £41.7 million, or approximately $50.0 million, upon first approval of lifileucel in advanced melanoma, (ii) deferred consideration based on double digit rates on global net sales (as defined in the Option Agreement) payable from the Company to the sellers following the completion of the Acquisition over a deferred consideration term of twelve years, and (iii) after the deferred consideration term, earnout payments payable from the Company to sellers following the completion of the transaction if deferred consideration payments are equal or greater than the deferred consideration amount provided for in the Option Agreement. These contingent payments were determined to be within the scope of ASC 450 and will be recognized when they are both probable and estimable. During the first quarter of 2024, the Company made the required milestone payment of $52.6 million (£41.7 million) upon the approval of the Company’s BLA of Amtagvi ® ​ The net assets acquired in the Acquisition were recorded by allocating the total cost of the Acquisition to the assets acquired on a relative fair value basis based on their estimated fair values as of May 18, 2023, which is the date that the Acquisition was completed. ​ The fair value of the developed technology was estimated using a multi-period excess earnings income approach that discounts expected cash flows to present value by applying a discount rate that represents the estimated rate that market participants would use to value the intangible assets. The fair value of the developed technology is being amortized over an expected useful life of 15 years and is recorded as Cost of Sales in the Company’s consolidated statement of operations. ​ The fair value of the assembled workforce was estimated using a replacement cost less depreciation method. The fair value of the assembled workforce is being amortized over an expected useful life of 3 years and is recorded as selling, general, and administrative expense in the Company’s consolidated statement of operations. ​ The weighted average amortization period the developed technology and assembled workforce ​ The fair value of the acquired inventory was determined using the comparative sales method of the market approach, which uses historical and expected average selling prices of inventory as the base amount to which adjustment for costs to complete for work-in-process, cost of disposal and reasonable profit allowance are applied. The inventory fair value adjustment is being amortized as cost of sales as the acquired inventories are sold. ​ A deferred tax liability was recognized on the temporary differences related to the book and tax basis of the acquired intangible assets. The deferred tax liability and resulting adjustment to the carrying amount of the acquired intangibles was calculated using the simultaneous equations method under ASC 740. The tax rate used is based on the estimated statutory rates in the United Kingdom as this is where the intangible assets are domiciled.

INTANGIBLE ASSETS, NET

INTANGIBLE ASSETS, NET	12 Months Ended
	Dec. 31, 2024
INTANGIBLE ASSETS, NET
INTANGIBLE ASSETS, NET	NOTE 5. INTANGIBLE ASSETS, NET The gross carrying amounts and net book value of intangible assets as of December 31, 2024 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ 2024 ​ 2023 Developed technology ​ $ 304,939 ​ $ 238,612 Assembled workforce ​ ​ 643 ​ ​ 652 Intellectual property license ​ ​ 7,500 ​ ​ — Total intangible assets ​ $ 313,082 ​ $ 239,264 Less: accumulated amortization ​ ​ (30,684) ​ ​ (10,006) Intangible assets, net ​ $ 282,398 ​ $ 229,258 ​ The Company recognized amortization expense of $21.2 million and $9.8 million during the years ended December 31, 2024 and December 31, 2023, respectively. Amortization expense for the developed technology and assembled workforce is recorded in cost of sales and selling, general, and administrative expense, respectively, in the consolidated statement of operations for the year ended December 31, 2024. ​ The total estimated amortization of the Company’s intangible assets the years ending December 31, 2025, 2026, 2027, 2028 and 2029 are $ 21.5 million, $21.4 million, $21.3 million, $21.3 million, and $21.3 million, respectively.

INVENTORY

INVENTORY	12 Months Ended
	Dec. 31, 2024
INVENTORY
INVENTORY	NOTE 6. INVENTORY As of December 31, 2024 and December 31, 2023, inventory consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ December 31, ​ ​ ​ 2024 ​ ​ 2023 Raw materials ​ $ 27,743 ​ $ — Work in process ​ ​ 8,765 ​ ​ 5,749 Finished goods ​ ​ 15,012 ​ ​ 4,623 Total inventory ​ $ 51,520 ​ $ 10,372 ​

REVENUE

REVENUE	12 Months Ended
	Dec. 31, 2024
REVENUE
REVENUE	NOTE 7. REVENUE Net revenue for the periods presented represents sales of Amtagvi ® ® ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ ​ 2024 ​ ​ 2023 ​ ​ 2022 Amtagvi ® ​ $ 103,567 ​ $ — ​ $ — Proleukin ® ​ ​ 60,503 ​ ​ 1,189 ​ ​ — Total net revenue ​ $ 164,070 ​ $ 1,189 ​ $ — ​ ​ Revenue from product sales was recorded net of GTN adjustments. The following table summarizes GTN adjustments for the periods presented (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ 2024 ​ ​ 2023 ​ ​ 2022 Gross revenue ​ $ 169,170 ​ $ 1,192 ​ $ — GTN adjustments: ​ ​ ​ ​ ​ ​ ​ ​ ​ Government rebates and chargebacks ​ ​ (172) ​ ​ — ​ ​ — Wholesaler fees and cash discounts ​ ​ (3,226) ​ ​ (3) ​ ​ — Other rebates, returns, discounts and adjustments ​ ​ (1,702) ​ ​ — ​ ​ — Total GTN adjustments ​ (5,100) ​ (3) ​ — Net revenue ​ $ 164,070 ​ $ 1,189 ​ $ — ​ ​ Consolidated net product revenue by geographic area for the periods presented is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ ​ 2024 ​ ​ 2023 ​ ​ 2022 United States ​ $ 161,043 ​ $ — ​ $ — Rest of world ​ ​ 3,027 ​ ​ 1,189 ​ ​ — Net revenue ​ $ 164,070 ​ $ 1,189 ​ $ — ​ Net product revenue in the U.S. is comprised of Amtagvi ® ® ® ® The following table summarizes the amount and percentage of gross revenue attributable to customers that represented more than 10% of the Company’s gross revenue and all other customers as a group for the years ended December 31, 2024 and December 31, 2023, respectively (in thousands, except percentages): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2024 ​ Year Ended December 31, 2023 ​ ​ ​ $ ​ ​ % ​ ​ $ ​ ​ % Customer A ​ $ 28,395 ​ ​ 17% ​ $ — ​ ​ 0% Other customers ​ ​ 140,775 ​ ​ 83% ​ ​ 1,192 ​ ​ 100% Gross revenue ​ $ 169,170 ​ ​ 100% ​ $ 1,192 ​ ​ 100% GTN adjustments ​ ​ (5,100) ​ ​ ​ ​ ​ (3) ​ ​ ​ Net revenue ​ $ 164,070 ​ ​ ​ ​ $ 1,189 ​ ​ ​ ​

PROPERTY AND EQUIPMENT, NET

PROPERTY AND EQUIPMENT, NET	12 Months Ended
	Dec. 31, 2024
PROPERTY AND EQUIPMENT, NET
PROPERTY AND EQUIPMENT, NET	NOTE 8. PROPERTY AND EQUIPMENT, NET Property and equipment, net consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2024 2023 Leasehold improvements ​ $ 67,375 ​ $ 76,804 Lab, process, and validation equipment ​ ​ 25,477 ​ ​ 23,131 Utility equipment ​ 5,990 ​ 5,990 Office furniture and equipment ​ 1,998 ​ 3,297 Computer software ​ ​ 8,512 ​ ​ 7,772 Computer equipment ​ 448 ​ 542 Machinery and equipment ​ ​ 363 ​ ​ 306 Construction in progress ​ 34,938 ​ 24,101 Total property and equipment, cost ​ $ 145,101 ​ $ 141,943 Less: Accumulated depreciation and amortization ​ (36,020) ​ (27,913) Property and equipment, net ​ $ 109,081 ​ $ 114,030 ​ Depreciation and amortization expense for the years ended December 31, 2024, 2023, and 2022 was approximately $12.0 million, $11.6 million and $9.3 million, respectively. As a result of the early termination of the former headquarters lease for the Company’s prior offices, the Company impaired approximately $7.4 million of long-lived assets, which included leasehold improvements, computer equipment and furniture and fixtures (See Note 15 – Leases).

ACCRUED EXPENSES

ACCRUED EXPENSES	12 Months Ended
	Dec. 31, 2024
ACCRUED EXPENSES
ACCRUED EXPENSES	NOTE 9. ACCRUED EXPENSES Accrued expenses consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ 2024 2023 Accrued payroll and employee related expenses ​ $ 31,910 ​ $ 34,814 Clinical related ​ ​ 13,017 ​ ​ 10,911 Manufacturing related ​ 10,084 ​ 10,893 Facilities related ​ ​ 6,748 ​ ​ 2,437 Legal and related services ​ 2,466 ​ 1,610 Inventory and distribution related ​ ​ 12,471 ​ ​ 2,148 Other accrued expenses ​ 5,240 ​ 6,593 Total accrued expenses ​ $ 81,936 ​ $ 69,406 ​

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2024
STOCKHOLDERS' EQUITY
STOCKHOLDERS' EQUITY	NOTE 10. STOCKHOLDERS’ EQUITY Common Stock The Company’s certificate of incorporation, as amended, authorizes the issuance of up to 500,000,000 shares of the Company’s common stock, par value $0.000041666 . As of December 31, 2024, 305,252,194 shares of the Company’s common stock were issued and outstanding . Public Offerings On February 22, 2024, the Company closed an underwritten public offering of 23,014,000 shares of its common stock at a public offering price of $9.15 per share, before underwriting discounts and commissions. The total net proceeds to the Company from the offering were $197.4 million after deducting underwriting discounts and commissions and offering expenses payable by the Company. On July 13, 2023, the Company closed an underwritten public offering of 23,000,000 shares of the Company’s common stock, which included 3,000,000 shares of common stock issued pursuant to the exercise of the option granted to the underwriters, at a public offering price of $7.50 per share, before underwriting discounts and commissions. The total net proceeds to the Company from the offering, including the exercise of the option by the underwriters, were $161.5 million after deducting underwriting discounts and commissions and offering expenses payable by the Company. At the Market Offering Program On November 18, 2022, the Company entered into an Open Market Sale Agreement (the “2022 Sale Agreement”) with Jefferies LLC (“Jefferies”). Under the terms of the 2022 Sale Agreement, the Company was able to, from time to time, at its sole discretion, issue and sell through Jefferies, acting as a sales agent, up to $500.0 million of shares of the Company’s common stock. On June 16, 2023, the Company entered into a new Open Market Sale Agreement (the “2023 Sale Agreement”), which superseded and replaced in its entirety the 2022 Sale Agreement, which was terminated by the Company. Under the terms of the 2023 Sale Agreement, the Company may, from time to time, in its sole discretion, issue and sell through Jefferies, acting as a sales agent, up to $450.0 million of shares of the Company’s common stock. The issuance and sale, if any, of the shares of common stock by the Company under the 2023 Sale Agreement was or will be made pursuant to a prospectus supplement dated June 16, 2023 to the Company’s Registration Statement on Form S-3ASR, which became effective immediately upon filing with the SEC on June 16, 2023. Pursuant to the 2023 Sale Agreement, Jefferies may sell the Common Shares by any method permitted by law deemed to be an “at the market” offering as defined in Rule 415 of the Securities Act of 1933, as amended. Jefferies will use commercially reasonable efforts consistent with its normal trading and sales practices to sell the Common Shares from time to time, based upon instructions from the Company (including any price or size limits or other customary parameters or conditions the Company may impose). The Company will pay Jefferies a commission of up to 3.0% of the gross sales proceeds of any Common Shares sold through Jefferies under the 2023 Sale Agreement. The Company is not obligated to make any sales of Common Shares under the 2023 Sale Agreement. The offering of Common Shares pursuant to the 2023 Sale Agreement will terminate upon the earlier to occur of (i) the issuance and sale, through Jefferies, of all Common Shares subject to the 2023 Sale Agreement and (ii) termination of the 2023 Sale Agreement in accordance with its terms. For the years ended December 31, 2024, 2023 and 2022, the Company received $200.0 million, $301.7 million, and $189.5 million in net proceeds, net of offering costs, through the sale of 23,127,726 shares, 44,080,226 shares and 29,788,993 shares of its common stock through the 2023 Sale Agreement and/or the 2022 Sale Agreement at a weighted average price per share of $8.82, $6.99 and $6.52, respectively. Preferred Stock The Company’s certificate of incorporation authorizes the issuance of up to 50,000,000 shares of “blank check” preferred stock. As of December 31, 2024, 17,000 shares were designated as Series A Convertible Preferred Stock and 11,500,000 shares were designated as Series B Convertible Preferred Stock. Series A Convertible Preferred Stock A total of 17,000 shares of Series A Convertible Preferred Stock have been authorized for issuance under the Company’s Certificate of Designation of Preferences and Rights of Series A Convertible Preferred Stock. The shares of Series A Convertible Preferred Stock have a stated value of $1,000 per share and are initially convertible into shares of common stock at a price of $2.00 per share, subject to adjustment. Each share of Series A Preferred Stock is initially convertible into 500 shares of common stock. The Series A Convertible Preferred Stock may, at the option of each investor, be converted into fully paid and non-assessable shares of common stock. The holders of shares of Series A Convertible Preferred Stock do not have the right to vote on matters that come before the Company’s stockholders. In the event of any dissolution or winding up of the Company, proceeds shall be paid pari passu among the holders of common stock and preferred stock, pro rata based on the number of shares held by each holder. The Company may not declare, pay or set aside any dividends on shares of capital stock of the Company (other than dividends on shares of common stock payable in shares of common stock) unless the holders of the Series A Convertible Preferred Stock shall first receive an equal dividend on each outstanding share of Series A Convertible Preferred Stock. No shares of Series A Convertible Preferred Stock were converted to common stock during the year ended December 31, 2024 and 2023. As of December 31, 2024, and 2023, 194 shares of Series A Convertible Preferred Stock (that are convertible into 97,000 shares of common stock) remained outstanding. Series B Convertible Preferred Stock ​ A total of 11,500,000 shares of Series B Convertible Preferred Stock are authorized for issuance under the Company’s Series B Certificate of Designation of Rights, Preferences and Privileges of Series B Convertible Preferred Stock. The shares of Series B Convertible Preferred Stock have a stated value of $4.75 per share and are convertible into shares of the Company’s common stock at an initial conversion price of $4.75 per share. Each share of Series B Preferred Stock is initially convertible into 1 share of common stock. The Series B Convertible Preferred Stock may, at the option of each investor, be converted into fully paid and non-assessable shares of common stock. The holders of Series B Convertible Preferred Stock do not have the right to vote on matters that come before the Company's stockholders. In the event of any dissolution or winding up of the Company, proceeds shall be paid pari passu among the holders of common stock and preferred stock, pro rata based on the number of shares held by each holder. Holders of Series B Convertible Preferred Stock are entitled to dividends on an as-if-converted basis in the same form as any dividends actually paid on shares of the Series A Convertible Preferred Stock or the Company’s common stock. So long as any Series B Convertible Preferred Stock remains outstanding, the Company may not redeem, purchase or otherwise acquire any material amount of the Series A Convertible Preferred Stock or any securities junior to the Series B Convertible Preferred Stock. No shares of Series B Convertible Preferred Stock were converted to common stock during the year ended December 31, 2024 and 2023. At December 31, 2024 and 2023, 2,842,158 shares of Series B Preferred Stock (that are convertible into 2,842,158 shares of common stock) remained outstanding. Equity Incentive Plans The Company has multiple equity incentive plans under which it grants awards. As of June 11, 2024, the Company’s stockholders approved the termination of the 2014 Equity Incentive Plan (the “2014 Plan”). In addition, the Company’s stockholders approved the recapture by the 2018 Equity Incentive Plan (the “2018 Plan”) of awards granted under the 2014 Plan that expire, terminate, or are cancelled or forfeited without being settled, vested, or exercised after the stockholders’ approval. On April 22, 2018, the Company’s Board of Directors (the “Board”) adopted the Iovance Biotherapeutics, Inc. 2018 Equity Incentive Plan (the “2018 Plan”), which was approved by the Company’s stockholders in June 2018. The 2018 Plan as approved initially authorized the issuance up to an aggregate of 6,000,000 shares of common stock in the form of incentive (qualified) stock options, non-qualified options, common stock, stock appreciation rights, restricted stock awards, restricted stock units, other stock-based awards, other cash-based awards or any combination of the foregoing. On June 8, 2020, the Company's stockholders approved an amendment to the 2018 Plan to increase the number of shares available for issuance upon the exercise of stock options under the 2018 Plan from 6,000,000 to 14,000,000 shares, which became effective immediately. Additionally, on June 10, 2022, the Company’s stockholders approved an amendment to the 2018 Plan to increase the number of shares available for issuance upon the exercise of stock options under the 2018 Plan from 14,000,000 to 20,700,000 shares, which became effective immediately. On June 6, 2023, the Company’s stockholders approved an amendment to the 2018 Plan to increase the number of shares available for issuance under the 2018 Plan from 20,700,000 to 29,700,000, which became effective immediately. On June 11, 2024, the Company’s stockholders approved an amendment to the 2018 Plan to increase the number of shares available for issuance under the 2018 Plan from 29,700,000 to 36,700,000 and permit share recapture from the 2014 Plan, which became effective immediately. As of December 31, 2024, 8,917,507 shares of common stock were available for grant under the Company’s 2018 Plan, including shares recaptured from the 2014 Plan. On September 22, 2021, the Board adopted the Iovance Biotherapeutics, Inc. 2021 Inducement Plan (the “2021 Inducement Plan”). The 2021 Inducement Plan provides for the grant of non-qualified options, common stock, stock appreciation rights, restricted stock awards, restricted stock units, other stock-based awards, other cash-based awards, or any combination of the foregoing. The 2021 Inducement Plan was recommended for approval by the Compensation Committee of the Board (the “Compensation Committee”), and subsequently approved and adopted by the Board without stockholder approval pursuant to Rule 5635(c)(4) of the rules and regulations of The Nasdaq Stock Market LLC (the “Nasdaq Listing Rules”). The Board initially reserved 1,000,000 shares of the Company’s common stock for issuance pursuant to equity awards granted under the 2021 Inducement Plan, and the 2021 Inducement Plan is administered by the Compensation Committee. On January 12, 2022, the Compensation Committee approved an amendment to the 2021 Inducement Plan solely to increase the number of shares reserved for issuance under the 2021 Inducement Plan from 1,000,000 shares of the Company’s common stock to 1,750,000 shares of the Company’s common stock without stockholder approval pursuant to Rule 5635(c)(4) of the Nasdaq Listing Rules. The Compensation Committee approved additional amendments to the 2021 Inducement Plan solely to increase the number of shares reserved for issuance under the 2021 Inducement Plan from 1,750,000 to 2,250,000 shares of the Company’s common stock on March 13, 2023, from 2,250,000 to 2,750,000 shares of the Company’s common stock on February 26, 2024, and from 2,750,000 shares to 4,750,000 shares on November 22, 2024 without stockholder approval pursuant to Rule 5635(c)(4) of the Nasdaq Listing Rules. In accordance with Rule 5635(c)(4) of the Nasdaq Listing Rules, equity awards under the 2021 Inducement Plan may only be made to an employee if such employee is granted such equity awards in connection with his or her commencement of employment with the Company or a subsidiary and such grant is an inducement material to his or her entering into employment with the Company or such subsidiary. In addition, awards under the 2021 Inducement Plan may only be made to employees who have not previously been an employee or member of the Board (or any parent or subsidiary of the Company) or following a bona fide period of non-employment of the employee by the Company (or a parent or subsidiary of the Company). As of December 31, 2024, 1,867,121 shares of common stock were available for grant under the Inducement Plan. Stock Options A summary of the status of stock options as of December 31, 2024, and the changes during the three years then ended, is presented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ Aggregate ​ ​ Number ​ Average ​ Remaining ​ Intrinsic ​ ​ of ​ Exercise ​ Contract ​ Value ​ Options Price Life (Years) ( in thousands) Outstanding at December 31, 2023 ​ 18,899,849 ​ $ 18.57 ​ ​ ​ $ ​ Issued ​ 1,731,325 ​ 9.72 ​ ​ ​ ​ ​ Exercised ​ (425,925) ​ 7.67 ​ ​ ​ ​ ​ Expired/Cancelled ​ (1,987,123) ​ 23.78 ​ ​ ​ ​ ​ Outstanding at December 31, 2024 ​ 18,218,126 $ 17.41 6.26 ​ $ 2,550 Ending vested and expected to vest at December 31, 2024 ​ 18,218,126 ​ $ 17.41 ​ 6.26 ​ $ 2,550 Options exercisable at December 31, 2024 14,137,830 ​ $ 19.96 5.56 ​ $ 1,527 ​ As of December 31, 2024, there was $20.8 million of total unrecognized compensation expense related to unvested employee stock options, which the Company expects to recognize over a remaining weighted average period of 1.71 The weighted average grant date fair value for employee options granted under the Company's stock option plans during the years ended December 31, 2024, 2023, and 2022 was $6.97, $4.91, and $8.29 per option, respectively. The aggregate intrinsic value in the table above reflects the total pre-tax intrinsic value (the difference between the Company’s closing stock price on the last trading day of the year ended December 31, 2024 and the exercise price of the options, multiplied by the number of in-the-money stock options) that would have been received by the option holders had all option holders exercised their options on December 31, 2024. The intrinsic value of the Company’s stock options changes based on the closing price of the Company’s common stock. The aggregate intrinsic value of stock options exercised during the year ended December 31, 2024, 2023, and 2022 were $1.1 million, $0.01 million, and $0.04 million, respectively. Employee Stock Purchase Plan In June 2020, the Company adopted the 2020 ESPP upon its approval by the Company’s shareholders at its Annual Stockholders Meeting on June 8, 2020. The Company reserved 500,000 shares of its common stock for issuance under the 2020 ESPP. On June 6, 2023, the Company's stockholders approved an amendment to the 2020 ESPP to increase the number of shares reserved for issuance under the 2020 ESPP from 500,000 shares of the Company’s common stock to 1,400,000 shares of the Company’s common stock, which became effective immediately. On June 11, 2024, the Company's stockholders approved an amendment to the 2020 ESPP, to increase the number of shares reserved for issuance under the 2020 ESPP from 1,400,000 to 1,900,000 shares of the Company’s common stock, which became effective immediately. ​ Under the 2020 ESPP, employees of the Company can purchase shares of its common stock based on a percentage of their compensation subject to certain limits. The purchase price per share is equal to the lower of 85% of the fair market value of its common stock on the offering date or the purchase date with a six-month look-back feature. The 2020 ESPP purchases are settled with common stock from the 2020 ESPP’s previously authorized and available pool of shares. The compensation expense related to the 2020 ESPP for the years ended December 31, 2024, 2023 and 2022 was $1.5 million, $1.2 million and $1.3 million, respectively. Under the 2020 ESPP, for the years ended December 31, 2024 and 2023, the Company received proceeds of $3.0 million for the issuance of 497,044 shares and $2.4 million for the issuance of 435,459 shares, respectively. As of December 31, 2024, there was $0.7 million of unrecognized compensation cost associated with the 2020 ESPP, which is expected to be recognized over 5.3 months. ​ Restricted Stock Units and Performance Restricted Stock Units ​ In addition to RSUs that have time-based vesting requirements, from time to time the Company may issue RSUs that include certain performance vesting criteria based upon the satisfaction of stated objectives (“PRSUs”). Compensation expense related to PRSUs is based on the grant date fair value of the award and recorded from the period that achievement is determined to be probable through the stated service period associated with the award. Activity for RSUs and PRSUs during the years ended December 31, 2024 and 2023 is presented in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Number ​ Average ​ ​ of ​ Grant Date ​ RSUs and PRSUs Fair Value Outstanding at December 31, 2023 ​ 3,453,901 ​ $ 8.97 Granted ​ 9,924,555 ​ ​ 16.53 Vested/Released ​ (3,150,172) ​ ​ 12.95 Canceled/Forfeited ​ (680,641) ​ ​ 15.09 Outstanding at December 31, 2024 ​ 9,547,643 ​ $ 15.08 Ending vested and expected to vest at December 31, 2024 ​ 9,547,643 ​ $ 15.08 ​ As of December 31, 2024 and 2023, there was $84.3 million and $19.9 million of unrecognized stock-based compensation expense associated with unvested RSUs, which the Company expects to recognize over a remaining weighted-average period of 1.61 and 1.65 ​ Stock-Based Compensation Total stock-based compensation expense related to the Company’s stock-based awards was recorded on the consolidated statements of operations as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ 2024 2023 2022 Cost of sales ​ $ 8,554 ​ $ — ​ $ — Research and development ​ ​ 49,270 ​ ​ 34,926 ​ ​ 50,242 Selling, general, and administrative ​ 51,799 ​ 27,699 ​ 33,780 Total stock-based compensation expense ​ $ 109,623 ​ $ 62,625 ​ $ 84,022 ​ The amount included in capitalized inventory for stock-based compensation expense for personnel engaged with manufacturing activities was $1.2 million as of December 31, 2024. No such cost was included in inventory as of December 31, 2023. ​ Total stock-based compensation expense by type of award was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ 2024 2023 2022 Stock option expense ​ $ 21,112 ​ $ 45,340 ​ $ 58,308 Restricted stock expense ​ 87,025 ​ 16,062 ​ 24,436 ESPP expense ​ 1,486 ​ 1,223 ​ 1,278 Total stock-based compensation expense ​ $ 109,623 ​ $ 62,625 ​ $ 84,022 ​ The following table summarizes the assumptions relating to options granted pursuant to the Company’s equity incentive plans for the years ended December 31, 2023, 2022, and 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock Options ​ ESPP ​ ​ Years Ended December 31, ​ Years Ended December 31, Assumptions: 2024 2023 2022 2024 2023 2022 Expected term (years) ​ 5.41 - 5.56 5.18 - 5.37 4.94 - 5.12 ​ 0.50 ​ 0.5 ​ 0.50 Expected volatility ​ 85.03% - 85.85% 83.63% - 84.21% 73.73% - 83.90% ​ 73.85% - 98.85% ​ 72.96% - 83.36% ​ 73.02% - 137.42% Risk-free interest rate ​ 3.61% - 4.33% ​ 3.59% - 4.60% ​ 1.25% - 4.05% ​ 4.35% - 5.40% ​ 5.38% - 5.40% ​ 1.98% - 4.78% Expected dividend yield ​ 0% ​ 0% ​ 0% ​ 0% ​ 0% ​ 0% ​ - Expected Term (Years) —The expected term of the stock option grants was calculated based on historical exercises, cancellations, and forfeitures of stock options and outstanding option shares. - Expected Volatility —The expected volatility is based on the historical volatility for the Company's stock over a period equal to the expected terms of the options. - Risk-Free Interest Rate —The risk-free interest rate was based on the market yield currently available on United States Treasury securities with maturities approximately equal to the option’s expected term. - Expected Dividend Yield —The Company has never paid dividends and does not expect to pay dividends in the foreseeable future. - Forfeiture Rate —The Company recognizes forfeitures as they occur. Each of the inputs discussed above is subjective and generally requires significant management judgment.

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Dec. 31, 2024
SEGMENT INFORMATION
SEGMENT INFORMATION	NOTE 11. SEGMENT INFORMATION The Company operates in one segment, focusing on innovating, developing, and commercializing therapies using its autologous TIL cell therapies for patients with solid tumor cancers. The Company is executing the U.S. launch of Amtagvi ® ® ® The Company’s Chief Operating Decision Maker (“CODM”) is the Chief Executive Officer, who uses net loss as measurement of segment loss and monitors results against budget to evaluate and assess performance of the Company and resource allocation within the Company. The measure of segment assets is reported on the balance sheet as total consolidated assets. The table below highlights the Company’s revenue, expenses and net loss for the segment and is reconciled to net loss on a consolidated basis for the year ended December 31, 2024 and 2023. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ Increase (Decrease) (in thousands) 2024 2023 ​ $ % Net sales $ 164,070 ​ $ 1,189 ​ 162,881 ​ 13,698 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Direct cost of goods sold (a) $ 83,637 ​ $ 663 ​ ​ ​ ​ Acquisition related cost of sales (b) $ 26,161 ​ $ 10,092 ​ ​ ​ ​ Royalties $ 14,197 ​ $ - ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total cost of sales $ 123,995 ​ $ 10,755 ​ 113,240 ​ 1,053 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development $ 200,361 ​ $ 278,032 ​ (77,671) ​ (27.9) General and administrative $ 97,153 ​ $ 88,960 ​ 8,193 ​ 9.2 Sales and marketing $ 26,986 ​ $ 21,376 ​ 5,610 ​ 26.2 Other segment items (c) $ 87,752 ​ $ 46,104 ​ 41,648 ​ 90.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total expenses $ 412,252 ​ $ 434,471 ​ (22,220) ​ (5.1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss $ (372,177) ​ $ (444,037) ​ (71,860) ​ (16.2) ​ ​ ​ a) Direct cost of goods sold represents inventory and period costs related to overhead and manufacturing costs of Amtagvi® as well as costs associated with the purchases and sales of Proleukin ® ® b) Acquisition related cost of sales represents amortization expenses for the developed technology intangible assets and the milestone payment recorded as part of the acquisition of Proleukin ® c) Other segment items include costs that are not considered significant expense segments nor reviewed by the CODM on a regular basis. Such amount includes stock-based compensation expenses, interest income, other income and expenses, and income tax benefits. ​

EMPLOYEE BENEFIT PLAN

EMPLOYEE BENEFIT PLAN	12 Months Ended
	Dec. 31, 2024
EMPLOYEE BENEFIT PLAN
EMPLOYEE BENEFIT PLAN	NOTE 12. EMPLOYEE BENEFIT PLAN The Company maintains a defined contribution plan covering substantially all U.S. employees under Section 401(k) of the Internal Revenue Code of 1986, as amended (the “IRC”). The Company's matching contribution to the defined contribution plan was $4.7 million, $4.1 million, and $3.0 million for the years ended December 31, 2024, 2023 and 2022, respectively. ​

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2024
INCOME TAXES
INCOME TAXES	NOTE 13. INCOME TAXES Loss before provision of income taxes consisted of U.S. losses of $359.9 million, $433.5 million, and $395.8 million, and foreign losses of $15.1 million, $14.0 million, and $0.1 million for the years ended December 31, 2024, December 31, 2023, and December 31, 2022, respectively. The Company recorded a tax benefit of $2.8 million and $3.5 million for the years ended December 31, 2024 and December 31, 2023, respectively, which resulted in an effective tax rate of 0.75% and 0.78% respectively. The income tax benefit for the periods presented primarily relates to operations in the United Kingdom and the movement of deferred tax assets and liabilities. No income tax benefit was recorded for the year ended December 31, 2022. The significant components of the Company’s net deferred tax assets and liabilities are summarized as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2024 2023 Deferred income tax assets: ​ ​ Net operating loss carryforwards ​ $ 302,875 ​ $ 255,639 Stock-based compensation ​ 40,909 ​ 28,609 Tax credit carryforwards ​ 66,874 ​ 58,565 Lease liabilities ​ ​ 14,759 ​ ​ 16,024 Capitalized R&D ​ ​ 137,577 ​ ​ 99,107 Reserves and accruals ​ 11,523 ​ 6,540 Deferred tax assets before valuation allowance ​ 574,517 ​ 464,484 Less: valuation allowance ​ (557,587) ​ (446,853) Net deferred income tax assets ​ 16,930 ​ 17,631 Deferred tax liabilities: ​ ​ ​ ​ Right-of-use assets ​ ​ (14,228) ​ ​ (13,381) Depreciation and amortization ​ (35,017) ​ (21,597) Net deferred tax assets (liabilities) ​ $ (32,315) ​ $ (17,347) ​ The reconciliation of the effective income tax rate to the U.S. statutory rate is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2024 2023 2022 Federal statutory tax rate 21 % 21 % 21 % Orphan drug and research credits 2 2 1 ​ Permanent and other differences (2) (1) (1) ​ Stock-based compensation (1) (1) (1) ​ State tax, net of federal benefit 10 1 1 ​ ​ 30 % 22 % 21 % Valuation allowance (29) % (21) % (21) % Effective tax rate 1 % 1 % — % ​ The Company had net operating loss carryforwards (“NOLs”) for federal, state, and foreign income tax purposes of approximately $1.3 billion, $331.9 million, and $15.2 million, respectively, as of December 31, 2024. $142.4 million of federal NOLs will expire beginning in 2027, while $1.2 billion generated after the recently enacted tax reform will have an indefinite life under the Tax Cuts and Jobs Act of 2017 (the “Tax Act”). The state NOLs will expire if unused in years 2030 through 2044. The foreign NOLs do not expire. The Company had $80.6 million of federal and $19.0 million of California research and development tax credit and other tax credit carryforwards available to offset future taxable income. The federal credits begin to expire in 2033, and the California research credits have no expiration dates. The Company’s utilization of NOLs and tax credits is subject to an annual limitation due to ownership changes that have occurred previously or that could occur in the future as provided in Section 382 of the Internal Revenue Code (“Section 382”), as well as similar state provisions. Section 382 limits the utilization of NOLs and tax credits when there is a greater than 50% change of ownership as determined under the regulations. Since its formation, the Company has raised capital through the issuance of capital stock and various convertible instruments which, combined with the purchasing shareholders’ subsequent disposition of these shares, has resulted in multiple ownership changes as defined by Section 382, and could result in ownership change in the future upon subsequent disposition. The Company’s utilization of NOLs and Tax Credits may also be adversely affected by future changes in federal and state tax laws and regulations. In assessing the realization of deferred tax assets, management considers whether it is more likely than not that some portion or all the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon future generation for taxable income during the periods in which temporary differences representing net future deductible amounts become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment. After consideration of all the information available, management continues to maintain a full valuation allowance against U.S. federal and state net deferred tax assets due to the Company’s cumulative loss position and lack of sufficient positive evidence to support the realizability of its U.S. net deferred tax assets. For the years ended December 31, 2024, 2023 and 2022, the change in the valuation allowance was approximately $110.7 million, $96.4 million, and $82.9 million, respectively. The Company evaluated the provisions of ASC 740 related to the accounting for uncertainty in income taxes recognized in an enterprise’s financial statements. ASC 740 prescribes a comprehensive model for how a company should recognize, present, and disclose uncertain positions that the Company has taken or expects to take in its tax return. For those benefits to be recognized, a tax position must be more-likely-than-not to be sustained upon examination by taxing authorities. Differences between tax positions taken or expected to be taken in a tax return and the net benefit recognized and measured pursuant to the interpretation are referred to as “unrecognized benefits.” A liability is recognized (or amount of NOL carry-forward or amount of tax refundable is reduced) for unrecognized tax benefits because it represents an enterprise’s potential future obligation to the taxing authority for a tax position that was not recognized as a result of applying the provisions of ASC 740. If applicable, interest costs related to the unrecognized tax benefits are required to be calculated and would be classified as income tax expenses in the consolidated statements of operations. Penalties would be recognized as a component of selling, general and administrative expenses in the consolidated statements of operations. A reconciliation of the beginning and ending balances of the unrecognized tax benefits during the years ended December 31, 2024, 2023 and 2022 is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ 2024 2023 2022 Unrecognized benefit - beginning of period ​ $ 26,107 ​ $ 21,645 ​ $ 18,171 Gross decreases - prior period tax positions ​ — ​ — ​ — Gross increases - current period tax positions ​ 3,747 ​ 4,462 ​ 3,474 Unrecognized benefit - end of period ​ $ 29,854 ​ $ 26,107 ​ $ 21,645 ​ No interest or penalties on unpaid tax were recorded during the years ended December 31, 2024, 2023, or 2022. The Company does not anticipate any significant changes within 12 months of this reporting date of its uncertain tax positions. The Company files tax returns in U.S. federal and state jurisdictions, as well as foreign jurisdictions. The U.S. federal and U.S. state taxing authorities may choose to audit tax returns for tax years beyond the statute of limitation period due to significant tax attribute carryforwards from prior years, making adjustments only to carryforward attributes. The Company is not currently under examination by income tax authorities in federal, state or other foreign jurisdictions. ​ The Inflation Reduction Act of 2022 (the “Act”), which includes certain new tax measures, was signed into law in August 2022. The Act contains two main tax provisions, a new corporate alternative minimum tax imposed on certain corporations meeting average annual financial statement income of more than $1 billion during a three-year tax period, and an excise tax imposed upon share repurchases by certain publicly traded corporations. The Act is effective for tax years beginning after December 31, 2022; however, the provisions of the Act will not have an impact on the Company’s consolidated financial statements. The Company will continue to monitor the effect of the Act and its impact on the Company.

LICENSES AND AGREEMENTS

LICENSES AND AGREEMENTS	12 Months Ended
	Dec. 31, 2024
LICENSES AND AGREEMENTS
LICENSES AND AGREEMENTS	NOTE 14. LICENSES AND AGREEMENTS National Institutes of Health (the “NIH”) and the National Cancer Institute (the “NCI”) Cooperative Research and Development Agreement (the “CRADA”) In August 2011, the Company signed a five-year CRADA with the NCI to work on the development of adoptive cell immunotherapies in multiple solid tumor types, including unmodified TIL as a stand-alone therapy or in combination, improved methods for the generation and selection of TIL cell therapy with anti-tumor reactivity, and strategies for more potent TILs. The CRADA has been amended since then to, among other things, extend the term of the CRADA, include new indications such as bladder, lung, triple-negative breast, and Human Papilloma Virus (“HPV”)-associated cancers, and modify the focus on the development of unmodified TIL as a stand-alone therapy or in combination, the evaluation in clinical trials of strategies for development of more potent TILs, such as selection of CD39/69 double negative cells and the use of certain inhibitors or other reagents in TIL expansion cultures. ​ In July 2024, the NCI and the Company entered into a fourth amendment to the CRADA to extend its term by an additional five years to August 2029. The fourth amendment also includes collaboration on preclinical and clinical development of enhanced tumor reactive TIL products for the treatment of a broad range of common epithelial cancers. Pursuant to the terms of the CRADA, as amended, the Company was required to make quarterly payments of $0.5 million to the NCI for support of research activities through the end of 2024. Commencing in 2025, the Company is required to make quarterly payments of $0.9 million to the NCI for support of research activities through the end of the CRADA’s term. To the extent the Company licenses patent rights relating to a TIL-based product candidate, the Company will be responsible for all patent-related expenses and fees, past and future, relating to the TIL-based product candidate. In addition, the Company may be required to supply certain test articles, including TIL, grown and processed under Current Good Manufacturing Practice (“cGMP”) conditions, suitable for use in clinical trials. The Company or the NCI may unilaterally terminate the CRADA for any reason or for no reason at any time by providing written notice at least 60 days before the desired termination date. The Company recorded costs associated with the CRADA of $2.0 million for each of the years ended December 31, 2024, 2023 and 2022, respectively, as research and development expenses. Patent License Agreement Related to the Development and Manufacture of TIL Cell Therapies The Company entered into an Exclusive Patent License Agreement (the “Patent License Agreement”) with the NIH, an agency of the U.S. Public Health Service within the Department of Health and Human Services, in 2011, as amended in 2015. Pursuant to the Patent License Agreement, as amended, the NIH granted the Company licenses, including exclusive, co-exclusive, and non-exclusive licenses, to certain technologies relating to autologous tumor infiltrating lymphocyte adoptive cell therapy products for the treatment of metastatic melanoma, lung, breast, bladder and HPV-positive cancers. In May 2021, the Company entered into an Amended and Restated Patent License Agreement with NIH, which included the grant of additional exclusive, worldwide patent rights in the indications to interleukin-15 and interleukin-21 cytokine-tethered TIL technology, and expanded the non-exclusive, worldwide field of use to all cancers. In August 2022, the Company entered into a Second Amended and Restated Patent License Agreement with NIH to include additional exclusive, worldwide patent rights to TIL products expressing interleukin-12, expanded rights to TIL selection technologies previously licensed under the Exclusive Patent License Agreement below, and additional non-exclusive, worldwide patent rights to certain technologies related to enhancing TIL potency. The Second Amended and Restated Patent License Agreement requires the Company to pay royalties based on a percentage of net sales in jurisdictions where patent rights exist, which percentage can fall into a tier that may be less than one percent to mid-single digits depending upon certain events, including the exclusivity of the rights, and the Company expects lower overall royalty payments as a result. The Company is also required to pay potential milestone payments on the achievement of certain clinical, regulatory, and commercial sales milestones for each of the indications and other direct costs incurred by the NIH pursuant to the Second Amended and Restated Patent License Agreement. The Company has made and anticipates making additional payments that could range from several hundred thousand dollars to the mid-single-digit millions of dollars in conjunction with certain development milestones, the approval of a BLA or its foreign equivalent, or the first U.S. and foreign commercial sales of any of its product candidates covered by the Second Amended and Restated Patent License Agreement. The term of the Second Amended and Restated Patent License Agreement continues until the expiry of the last-to-expire patent rights licensed thereunder, and the agreement contains standard termination provisions. The Company paid and recorded a $0.6 million milestone payment for an intellectual property license that was payable within 60 days of successful completion of the first Company-sponsored Phase 2 clinical study in melanoma, as research and development expenses, for the year ended December 31, 2023. The Company also paid a $1.5 million milestone payment for an intellectual property license that was payable within 60 days of the approval of Amtagvi ® ® Exclusive Patent License Agreement Related to TIL Selection On February 10, 2015, the Company entered into an exclusive patent license agreement (the “Exclusive Patent License Agreement”) with the NIH under which the Company received an exclusive, worldwide license under the selected TIL patents. This license was superseded and replaced by the Second Amended and Restated Patent License Agreement. H. Lee Moffitt Cancer Center Research Collaboration and Clinical Grant Agreements with Moffitt In June 2020, the Company entered into a Sponsored Research Agreement (the “SRA”) with the H. Lee Moffitt Cancer Center (“Moffitt”), with a term that ended either upon completion of the research thereunder or on July 1, 2022, whichever is sooner. The SRA has been extended multiple times and currently has an expiration date of May 31, 2025. The Company recorded research and development costs of $0.2 million, $0.2 million and $0.6 million for each of the years ended December 31, 2024, 2023 and 2022, respectively. The University of Texas M.D. Anderson Cancer Center Strategic Alliance Agreement In April 2017, the Company entered into a Strategic Alliance Agreement (the “SAA”) with The University of Texas M.D. Anderson Cancer Center (“MDACC”) under which the Company and MDACC agreed to conduct clinical and preclinical research studies. The Company agreed in the SAA to provide total funding not to exceed approximately $14.2 million for the performance of the multi-year studies under the SAA, of which approximately $5.3 million has been funded to date and has been recorded as research and development expense. In return, the Company acquired all rights to inventions resulting from the studies and has been granted a non-exclusive, sub-licensable, royalty-free, and perpetual license to specified background intellectual property of MDACC reasonably necessary to exploit, including the commercialization thereof. The Company has also been granted certain rights in clinical data generated by MDACC outside of the clinical trials to be performed under the SAA. The SAA’s term shall continue in effect until the later of the fourth anniversary of the SAA or the completion or termination of the research and receipt by the Company of all deliverables due from MDACC thereunder. On March 28, 2024, the Company and MDACC entered into the first amendment to the SAA, under which both parties agreed to conduct additional preclinical research studies. The Company recorded a benefit of $0.4 million, for the year ended December 31, 2024, as a result of finalization of the cost reconciliation. For the years ended December 31, 2023 and 2022, the Company recorded $0.0 and $0.2 million associated with the SAA as research and development expenses, respectively. WuXi Advanced Therapies, Inc. In November 2016, the Company entered into a manufacturing services agreement (the “First Wuxi MSA”) with WuXi Apptec, Inc. (“WuXi Apptec”) pursuant to which WuXi Apptec agreed to provide manufacturing and other services for two cGMP manufacturing suites for clinical manufacturing and related testing services. The First WuXi MSA was amended and restated in December 2017, further amended and restated and assigned to the Company’s subsidiary Iovance Biotherapeutics Manufacturing LLC (“Iovance Manufacturing LLC”), and Wuxi Advanced Therapies, Inc. in January 2020, and further amended in November 2020 and December 2021. The First WuXi MSA expired in November 2022. In October 2022, Iovance Manufacturing LLC entered into an additional three-year manufacturing and services agreement (the “Second Wuxi MSA”) with WuXi Advance Therapies, Inc. and its parent company, WuXi Apptec Co., Ltd (collectively, “WuXi”). Under the Second WuXi MSA, Iovance Manufacturing LLC entered into a statement of work for two cGMP manufacturing suites to be operated by WuXI for Iovance Manufacturing LLC to support clinical and commercial manufacturing and related testing services. The Second WuXi MSA and its related statement of work superseded the statements of work under the First WuXi MSA with respect to manufacturing in the two suites and expire on December 31, 2025. Iovance Manufacturing LLC may unilaterally terminate the statement of work for clinical and commercial manufacturing with written notice of written notice of 6 months in year 3 of the term. The Company recorded costs associated with agreements with WuXi of $25.0 million, $17.3 million, and $14.2 million for the years ended December 31, 2024, 2023, and 2022, respectively, as costs and expenses included in the consolidated statement of operations or as inventory in the consolidated balance sheets. Cellectis S.A In December 2019, the Company entered into a research collaboration and exclusive worldwide license agreement whereby the Company will license gene-editing technology from Cellectis S.A. (“Cellectis”), a clinical-stage biopharmaceutical company, to develop TIL cell therapies that have been genetically edited, including a PD-1 inactivated product that the Company refers to as IOV-4001. Financial terms of the license include annual license payments and development, regulatory and sales milestone payments from the Company to Cellectis, as well as royalty payments based on net sales of TALEN ® Novartis Pharma AG and Related Entities ​ In January 2020, the Company obtained a license from Novartis Pharma AG (“Novartis”) to develop and commercialize an antibody cytokine engrafted protein, which the Company refers to as IOV-3001. Under the agreement, the Company paid an upfront payment to Novartis and may pay future milestones related to initiation of patient dosing in various phases of clinical development for IOV-3001 and approval of the product in the U.S., EU and Japan. Novartis is also entitled to low-to-mid single digit percentage royalties from commercial sales of the product. The Company recorded costs associated with the license agreement from Novartis of $10.0 million as research and development expenses for the year ended December 31, 2020. No expenses were recorded for the years ended December 31, 2024, 2023 and 2022, respectively. ​ On May 18, 2023, as part of the completion of the Acquisition, the Company inherited two historical asset purchase agreements, one historical master cell bank license and working cell bank transfer agreement and one historical license agreement from Clinigen with Novartis AG, Novartis Pharma AG and Novartis Vaccines and Diagnostics, Inc. pursuant to which, among other things, the Company may be required to make future milestone payments based on net sales (as defined in the relevant underlying agreements) in the U.S. and the rest of world, which includes any and all sales outside of the U.S. The maximum amount of these milestone payments payable under these agreements is $30.0 million upon reaching several certain net sales amounts in the United States and $15.0 million upon reaching several certain net sales amounts in the rest of the world, of which 25% of each milestone payment will be reimbursed by Clinigen by deduction from the deferred consideration due under the Option Agreement in the period such milestone payment is made. To date, the net sales milestones have not been achieved, and, therefore, no payments were made under these agreements for the years ended December 31, 2024 and 2023, respectively. ​ Boehringer Ingelheim Biopharmaceuticals GmbH On May 18, 2023 as part of the completion of the Acquisition, the Company inherited a manufacturing and supply agreement from Clinigen with Boehringer Ingelheim Biopharmaceuticals GmbH (“BI”) pursuant to which BI will carry out the processing, manufacturing and supply of Proleukin ®

LEASES

LEASES	12 Months Ended
	Dec. 31, 2024
LEASES
LEASES	NOTE 15. LEASES Operating Leases The Company leases corporate office space in San Carlos, California, manufacturing, research and development lab facilities and office space in Philadelphia, Pennsylvania, including 136,000 square feet of commercial manufacturing and lab space at the i The Company’s leases have remaining lease terms that range from less than one year to approximately 16 years. Some of the Company’s leases include one or more options to renew with renewal terms that can extend the lease for additional years, or options to terminate the leases, both at the Company’s discretion. The Company’s leases may include options to extend or terminate the lease, which is considered in the lease term when it is reasonably certain that the Company will exercise any such options. Lease expense for minimum lease payments is recognized on a straight-line basis based on the fixed components of a lease arrangement. Variable lease cost is determined based on performance or usage in accordance with the contractual agreements and not based on an index or rate. Such costs that are not fixed in nature are recognized as incurred. The Company also leases certain furniture and equipment that has a lease term of 12 months or less. Since the lease agreements do not include an option to purchase the underlying asset, the Company elected not to apply the recognition requirements of Topic 842 for short-term leases, however, the lease costs that pertain to the short-term leases are disclosed in the components of lease costs table below. Relocation of the Headquarters Office Lease On November 15, 2024, the Company entered into a sublease agreement (the “New Headquarters Lease”) to relocate its office within the same building of its former San Carlos headquarters to lease approximately 16,731 square feet office space with the lease term of 24 months. The New Headquarters Lease commenced on December 15, 2024 and includes two options to extend the terms of the lease for 12 months each, exercisable under certain conditions and at a rate increase by 3% from the applicable monthly base rent of approximately $0.1 million. Upon the commencement date, the Company recognized operating lease liabilities and right-of-use assets of $2.3 million. Simultaneously, the Company entered into an Agreement for Termination of Lease and Voluntary Surrender of Premises with its landlord related to its lease for its then existing and now former headquarters location to surrender 49,918 square feet office and laboratory space and paid an early lease termination payment to its landlord of $0.6 million and $2.5 million of related brokerage fees. In accordance with ASC 842, the termination of this lease resulted in derecognition of right-of-use assets and corresponding lease liabilities of $13.7 million and $22.3 million, respectively, which resulted in a $8.6 million gain, partially offset by the aforementioned lease termination related fees, recorded as interest and other income, net in the consolidated statement of operations for the year ended December 31, 2024. In addition, as a result of the early termination of the former headquarters lease, the Company impaired approximately $7.4 million of long-lived assets, which included leasehold improvements, and furniture and fixtures, previously funded by the landlord through a tenant improvement allowance for the former corporate headquarters office lease (as discussed further below), and is included in the research and development expenses and selling, general and administrative expenses in the consolidated statement of operations for the year ended December 31, 2024. Manufacturing Contracts The Company uses contract manufacturing organizations (collectively the “CMOs” and each a “CMO”) to manufacture and supply TILs for clinical and commercial purposes. The CMO contractual obligations consist of the use of manufacturing facilities and minimum fixed commitment fees, such as personnel, general support fees, and minimum production or material fees. In addition to the minimum fixed commitment fees, the CMO contractual obligations include variable costs such as production and material costs in excess of the minimum quantity specified in each CMO agreement. During the term of each CMO agreement, the Company has access to and control of the use of a dedicated suite in each of the CMOs’ facilities for manufacturing activities. The contracts with CMOs generally contain embedded operating leases based on the fact that the suites are used for the Company’s production are implicitly identified, are used exclusively by the Company during the contractual term of the arrangements, and the CMOs have no substantive contractual rights to substitute the facilities used by the Company. Further, the Company controls the use of the facilities by obtaining all of the economic benefits from the use of the facilities and directs the use of the facilities throughout the period of use. The terms of the CMO contracts include options to terminate the lease with advance notice of five to six months. The termination clauses and extension clauses are included in the calculation of the lease term for each of the CMOs when it is reasonably certain that it will not exercise such options. For contracts with multiple deliverables, Topic 842 requires the Company to first identify a lease deliverable and non-lease deliverable included in the arrangements, and then allocate the fixed contractual consideration to the lease deliverable(s) and the non-lease deliverable(s) on a relative standalone selling price basis to determine the amount of operating lease right-of-use assets and liabilities. The Company identified the use of a dedicated suite as a single lease deliverable, and related labor services as a single non-lease deliverable in each of the CMO arrangements. Judgment is required to determine the relative standalone selling price of each deliverable as the observable standalone selling prices are not readily available. Therefore, management uses estimates and assumptions in determining relative standalone selling price of lease of a suite and labor service using information that includes market and other observable inputs to the extent possible. The balance sheet classification of the Company’s right-of-use asset and lease liabilities was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, ​ ​ 2024 ​ 2023 Operating lease right-of-use assets $ 55,201 $ 62,515 Operating lease liabilities ​ ​ Current portion included in current liabilities ​ 12,896 ​ 7,777 Long-term portion included in non-current liabilities ​ 44,365 ​ 67,085 Total operating lease liabilities ​ $ 57,261 ​ $ 74,862 ​ The following table summarizes components of lease expenses, which were included in total expenses in the Company’s consolidated statements of operations and in inventory in the consolidated balance sheets, and other information related to the Company’s operating leases as follows (in thousands, except weighted-average remaining lease terms and discount rates): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year ​ For the Year ​ ​ Ended ​ Ended ​ December 31, 2024 December 31, 2023 Operating lease cost ​ $ 16,484 ​ $ 17,786 ​ Variable lease cost ​ ​ 3,995 ​ 7,629 ​ Short-term lease cost ​ ​ 431 ​ 335 ​ Total lease cost ​ $ 20,910 ​ $ 25,750 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other information ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities included in cash flows from operations ​ $ 18,120 ​ $ 16,871 ​ Right-of-use assets obtained from entering new leases ​ $ 2,306 ​ $ 177 ​ Increase in right-of-use assets from lease modifications ​ $ 818 ​ $ 1,033 ​ Weighted-average remaining lease terms (years) ​ ​ 12.83 ​ ​ 13.09 ​ Weighted-average discount rates ​ ​ 7.9 % ​ 7.4 % ​ As of December 31, 2024, maturities of the Company's operating lease liabilities were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CMO ​ ​ ​ ​ Facility ​ embedded ​ ​ ​ Year Ending December 31, ​ leases leases Total 2025 ​ $ 6,039 ​ $ 10,910 ​ $ 16,949 2026 ​ 5,452 ​ — ​ 5,452 2027 ​ 4,307 ​ — ​ 4,307 2028 ​ 4,393 ​ — ​ 4,393 2029 ​ 4,481 ​ — ​ 4,481 Thereafter ​ 57,496 ​ — ​ 57,496 Total lease payments ​ $ 82,168 ​ $ 10,910 ​ $ 93,078 Less: Present value adjustment ​ (35,179) ​ (638) ​ (35,817) Operating lease liabilities ​ $ 46,989 ​ $ 10,272 ​ $ 57,261 ​ ​

LEGAL PROCEEDINGS

LEGAL PROCEEDINGS	12 Months Ended
	Dec. 31, 2024
LEGAL PROCEEDINGS
LEGAL PROCEEDINGS	NOTE 16. LEGAL PROCEEDINGS ​ Shumacher Derivative Lawsuit. ​ Ohio Laborers Derivative Lawsuit. ​ Solomon Capital, LLC. Solomon Capital, LLC, Solomon Capital 401(K) Trust, Solomon Sharbat and Shelhav Raff v. Lion Biotechnologies, Inc. The complaint further alleges that the Company agreed to (i) provide them with promissory notes totaling $0.2 million, plus interest, (ii) issue a total of 1,110 shares to the Solomon Plaintiffs (after the 1-for-100 the next financing of the Company on the same terms offered to other investors, which Solomon Plaintiffs allege, should have given them the right to convert their advances and payments into shares of the Company's common stock in the restructuring that took effect in May 2013. Based on the foregoing, the Solomon Plaintiffs allege causes for breach of contract and unjust enrichment and demand judgment against the Company in an unspecified amount exceeding $1.5 million, plus interest. On June 3, 2016, the Company filed an answer and counterclaims in the lawsuits. The Company has asserted counterclaims for fraudulent inducement, fraudulent misrepresentation, fraudulent concealment, breach of fiduciary duty, and breach of contract, alleging principally that the counterclaim defendants misrepresented their qualifications and failed to disclose that Solomon Sharbat was the subject of an investigation by the Financial Industry Regulatory Authority (“FINRA”) that resulted in the loss of his FINRA license. In its counterclaims, the Company is seeking damages in an amount exceeding $0.5 million and an order rescinding any and all agreements that the Solomon Plaintiffs contend entitled them to obtain shares of Company stock. On May 12, 2020, the court granted the Company’s motion for summary judgment limiting the Solomon Plaintiffs’ damages for the Equity Claim to $47,420. The Solomon Plaintiffs filed a notice of appeal of this summary judgment on June 9, 2020. On July 2, 2020, the court granted the Company’s motion to dismiss the First Solomon Suit for want of prosecution. On January 4, 2021, the court granted the Solomon Plaintiffs motion for reconsideration and reinstituted the case. On January 15, 2021, the Company filed a notice of appeal of the court’s grant of the Solomon Plaintiffs motion for reconsideration. On May 11, 2021, the Appellate Division upheld the court’s grant of the Solomon Plaintiffs’ motion for reconsideration of the dismissal of the First Solomon Suit for want of prosecution. On January 22, 2025, Solomon Sharbat and Shelhav Raff (through new legal counsel) filed a motion for leave to file an amended complaint in the First Solomon Suit. On September 27, 2019, the Solomon Plaintiffs filed a new lawsuit (through new legal counsel) (the “Second Solomon Suit”) titled Solomon Capital, LLC, Solomon Capital 401(K) Trust, Solomon Sharbat and Shelhav Raff v. Iovance Biotherapeutics, Inc., f/k/a/ Lion Biotechnologies Inc. f/k/a/ Genesis Biopharma Inc., and Manish Singh a monetary award pursuant to the District Court’s Rule 11 order and orders for attorneys’ fees and costs. On October 9, 2024, the Second Circuit Court stated that it will dismiss the appeal unless the Solomon Plaintiffs post the appeal bond by October 23, 2024. The Solomon Plaintiffs then moved for an extension of time until November 23, 2024 to post the appeal bond. The Company filed an opposition to the motion. The Second Circuit Court denied the Solomon Plaintiffs’ motion for an extension of time on November 7, 2024, and dismissed the appeal on November 8, 2024. The Company intends to vigorously defend these complaints and pursue its counterclaims, as applicable. At the current stage of the litigation, in both the First Solomon Suit and the Second Solomon Suit, it is not possible to estimate the amount or range of possible loss that might result from an adverse judgment or a settlement of these matters. The Company has been and may continue to be involved, from time to time, in legal proceedings and claims arising in the ordinary course of its business. Such matters are subject to many uncertainties and outcomes are not predictable with assurance. The Company accrues amounts, to the extent they can be reasonably estimated, that it believes are adequate to address any liabilities related to legal proceedings and other loss contingencies that it believes will result in a probable loss. While there can be no assurances as to the ultimate outcome of any legal proceeding or other loss contingency involving the Company, management does not believe any pending matter will be resolved in a manner that would have a material adverse effect on its financial position, results of operations or cash flows.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ (372,177)	$ (444,037)	$ (395,893)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Cybersecurity Risk Management a

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Risk Management and Strategy ​ We have designed and implemented a cybersecurity program which includes administrative, technical, and physical controls and processes to manage and mitigate material risks from internal and external cybersecurity threats, including but not limited to the following: ​ ● A team responsible for designing, implementing, and continually improving our policies, procedures, and technology. ● A risk management process to identify, assess, and treat internal and external ( third-party ) cybersecurity risks. ● An incident management program to effectively and efficiently identify, review, and escalate incidents with the appropriate stakeholders (e.g., CEO, CFO, Legal, Finance, and others, as required). ● A vulnerability management program to scan and penetration test, on an ongoing basis, our systems and networks to identify and treat identified vulnerabilities. ● A security awareness program that educates our team members on an ongoing basis on internal security policies and secure behaviors. ● Engage with key vendors, industry participants and intelligence and law enforcement communities as part of continuing efforts to evaluate and enhance the effectiveness of our information security program. ● Periodically reporting risks , previous and current incidents, and ways to mitigate risks to the Chief Executive Officer, the Audit Committee of the Board of Directors, and other members of senior management . As of the date of this report, we are not aware of any material risks from cybersecurity threats, including as a result of any previous cybersecurity incidents, that have materially affected our business strategy, results of operations, or financial condition. However, as discussed under “Risk Factors” in Part I, Item 1A of this Annual Report, cybersecurity threats pose multiple risks to us, including potentially to our results of operations and financial condition. Refer to Item 1A – “ Our internal computer systems, or those used by our CROs or other contractors or consultants, may fail or suffer security breaches We are dependent on information technology, systems, infrastructure and data
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	We have designed and implemented a cybersecurity program which includes administrative, technical, and physical controls and processes to manage and mitigate material risks from internal and external cybersecurity threats, including but not limited to the following: ​ ● A team responsible for designing, implementing, and continually improving our policies, procedures, and technology.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Governance: ● Board of Directors The Audit Committee operates under a written charter adopted by the Company’s Board of Directors. The Audit Committee oversees, among other things, a system of internal controls, including internal controls designed to assess, identify, and manage material risks from cybersecurity threats. The Audit Committee is also responsible for the adequacy and effectiveness of the Company’s internal controls, including those internal controls that are designed to assess, identify, and manage material risks from cybersecurity threats. For further information about the Audit Committee’s role in assessing and managing the registrant’s material risks from cybersecurity threats, see “Risk Management and Strategy,” under this Item 1C. ● Management Our team of cybersecurity professionals is led by our Vice President, Infrastructure and Security, who along with other members of the IT team collectively over extensive experience in the cybersecurity space in both the pharmaceutical and non-pharmaceutical sectors, many of whom have obtained professional security certifications. The IT team has primary responsibility for our overall cybersecurity risk management program and supervises both our internal cybersecurity personnel and our retained external cybersecurity consultants. For further information about Management’s role in assessing and managing the registrant’s material risks from cybersecurity threats, see “Risk Management and Strategy,” under this Item 1C.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	Audit Committee
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit Committee operates under a written charter adopted by the Company’s Board of Directors. The Audit Committee oversees, among other things, a system of internal controls, including internal controls designed to assess, identify, and manage material risks from cybersecurity threats. The Audit Committee is also responsible for the adequacy and effectiveness of the Company’s internal controls, including those internal controls that are designed to assess, identify, and manage material risks from cybersecurity threats. For further information about the Audit Committee’s role in assessing and managing the registrant’s material risks from cybersecurity threats
Cybersecurity Risk Role of Management [Text Block]	● A risk management process to identify, assess, and treat internal and external ( third-party ) cybersecurity risks. ● An incident management program to effectively and efficiently identify, review, and escalate incidents with the appropriate stakeholders (e.g., CEO, CFO, Legal, Finance, and others, as required). ● A vulnerability management program to scan and penetration test, on an ongoing basis, our systems and networks to identify and treat identified vulnerabilities. ● A security awareness program that educates our team members on an ongoing basis on internal security policies and secure behaviors. ● Engage with key vendors, industry participants and intelligence and law enforcement communities as part of continuing efforts to evaluate and enhance the effectiveness of our information security program. ● Periodically reporting risks , previous and current incidents, and ways to mitigate risks to the Chief Executive Officer, the Audit Committee of the Board of Directors, and other members of senior management .
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	Our team of cybersecurity professionals is led by our Vice President, Infrastructure and Security, who along with other members of the IT team
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Our team of cybersecurity professionals is led by our Vice President, Infrastructure and Security, who along with other members of the IT team collectively over extensive experience in the cybersecurity space in both the pharmaceutical and non-pharmaceutical sectors, many of whom have obtained professional security certifications.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	● Periodically reporting risks , previous and current incidents, and ways to mitigate risks to the Chief Executive Officer, the Audit Committee of the Board of Directors, and other members of senior management .
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES (Policies)	12 Months Ended
	Dec. 31, 2024
SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES
Cash, Cash Equivalents, and Investments	Cash, Cash Equivalents, and Investments The Company’s cash and cash equivalents include short-term investments with original maturities of three months or less when purchased. The Company's investments are classified as “available-for-sale.” The Company includes these investments in current assets or non-current assets in the Consolidated Balance Sheets based on the length of maturity from the reporting date and carries them at fair value. Unrealized gains and losses on available-for-sale securities are recorded in accumulated other comprehensive loss. Impairment losses related to credit losses (if any) are recorded as an allowance for credit losses with an offsetting entry to Interest income, net. No impairment losses related to credit losses were recognized for the years ended December 31, 2024, 2023 and 2022. The cost of debt securities is adjusted for the amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in Interest income, net in the consolidated statements of operations. Gains and losses on securities sold are recorded based on the specific identification method and are included in Interest income, net in the consolidated statements of operations. The Company has not incurred any realized gains or losses from sales of securities to date. The Company’s investment policy limits investments to certain types of instruments such as certificates of deposit, money market instruments, obligations issued by the U.S. government and U.S. government agencies as well as corporate debt securities and commercial paper, and places restrictions on maturities and concentration by type and issuer, except for securities issued by the U.S. government.
Restricted Cash	Restricted Cash As of December 31, 2024 and December 31, 2023, restricted cash totaled $6.4 million and $66.4 million, respectively. These amounts have been classified as either current or non-current assets in the Company’s consolidated balance sheet based on the maturity date of the underlying letter of credit agreement. The Company maintains a required minimum balance in segregated bank accounts in connection with its letters of credit for which amounts are restricted as to their use by the Company. As of December 31, 2024, the Company’s letters of credit were primarily comprised of a letter of credit for the benefit of the i A letter of credit in the amount of $60.0 million for the regulatory approval milestone payment as required by the terms of the Option Agreement for the Proleukin ® ® The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ 2024 ​ 2023 ​ 2022 Cash and cash equivalents ​ $ 115,694 ​ $ 114,888 ​ $ 231,731 Restricted cash ​ 6,359 ​ 66,430 ​ 6,430 Total cash, cash equivalents and restricted cash ​ $ 122,053 ​ $ 181,318 ​ $ 238,161 ​
Asset Acquisitions	Asset Acquisitions ​ The Company evaluates acquisitions of assets using the guidance in Accounting Standard Codification (“ASC”) Topic 805, Business Combinations (“ASC 805”), to determine whether the transaction should be accounted for as a business combination or asset acquisition by first applying a screen test to assess if substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of assets. If the screen test is met, the transaction is accounted for as an asset acquisition. If the screen test is not met, further assessment is required to determine whether the Company has acquired inputs and processes that have the ability to create outputs, which would meet the requirements of a business. If the assets acquired do not constitute a business, the Company accounts for asset acquisitions using the cost accumulation and allocation method. Under this method, the cost of the acquisition, including direct acquisition-related costs, is allocated to the assets acquired on a relative fair value basis. Goodwill is not recognized in an asset acquisition and any difference between consideration transferred and the fair value of the net assets acquired is allocated to the identifiable assets acquired based on their relative fair values. Deferred tax liabilities arising from basis differences in assets acquired are calculated using the simultaneous equations method under ASC Topic 740, Income Taxes (“ASC 740”), and based on the effective tax rate. The resulting deferred tax liability is recorded in the consolidated balance sheet as of December 31, 2024. Contingent consideration in the scope of ASC Topic 815, Derivatives and Hedging (“ASC 815”), is included in the cost of the asset acquisition at its acquisition date fair value. Contingent consideration in the scope of ASC Topic 450, Contingencies (“ASC 450”), is recognized when it is both probable and reasonably estimable.
Inventory and Cost of Sales	Inventory and Cost of Sales ​ Inventory is stated at the lower of cost or net realizable value on a first-in, first-out basis. Cost includes amounts related to materials, internal labor, costs of external manufacturing, and allocable depreciation of manufacturing facilities, equipment and overhead. Net realizable value is the estimated selling price in the ordinary course of business less reasonably predictable costs of completion, disposal and transportation. Inventoriable c osts incurred, such as manufacturing costs incurred prior to regulatory approval that did not qualify for capitalization and clinical manufacturing costs, are expensed as incurred as research and development expenses. Upon the February 2024 approval of Amtagvi ® ® Proleukin ® ® The Company periodically reviews inventory for excess and obsolescence, considering factors such as its most recent sales forecast compared to quantities on hand and the expiration date of the product and materials. The Company adjusts its inventory that is obsolete or otherwise unmarketable to its estimated net realizable value in the period in which the impairment is first identified. Any such adjustments are included as a component of cost of sales within the Company’s consolidated statements of operations. Cost of sales includes inventory and period costs related to overhead and manufacturing costs of Amtagvi ® ® ® During the Company’s commercial manufacturing process, certain Amtagvi ®
Trade Accounts Receivable	Trade Accounts Receivable ​ Trade accounts receivable are recorded net of allowances for product returns and estimated credit losses. The estimate of allowance for credit losses considers factors, including existing contractual payment and the aging of receivable from its customers. To date, the Company has determined that an allowance for credit losses is not required.
Intangible Assets	Intangible Assets ​ The Company’s intangible assets are initially measured based on an allocation of the cost of the acquisition to the assets acquired on a relative fair value basis and are recorded net of accumulated amortization. The Company amortizes the intangible assets on a straight-line basis over their estimated useful lives. When contingent consideration is a component of the cost of an asset acquisition, the Company capitalizes the amount of incremental cost from the contingent consideration related to the intangible asset acquired in the period the underlying contingency is resolved. When this occurs, the Company will recognize amortization expense on the incremental cost prospectively from the date the incremental costs are capitalized. The Company reviews intangible assets for impairment at least annually and whenever events or changes in circumstances have occurred which could indicate that the carrying value of the assets are not recoverable. If such indicators are present, the Company assesses the recoverability of affected assets by determining if the carrying value of the assets is less than the sum of the undiscounted future cash flows of the assets. If the assets are found to not be recoverable, the Company measures the amount of impairment by comparing the carrying value of the assets to their fair values. The Company determined that no indicators of impairment existed as of December 31, 2024.
Leases	Leases The Company determines if an arrangement includes a lease at inception and thereafter, if modified. Operating leases are included in its consolidated balance sheets as Operating lease right-of-use assets and Operating lease liabilities as of December 31, 2024 and 2023. Operating lease right-of-use assets represent the Company’s right to use an underlying asset for the lease term and operating lease liabilities represent the Company’s obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date or modification date based on the present value of lease payments over the lease term. In determining the net present value of lease payments, the Company uses an estimated incremental borrowing rate that is applicable to the Company based on the information available at the later of the lease commencement or modification date. The operating lease right-of-use assets also include any lease payments made less lease incentives. The Company’s leases may include options to extend or terminate the lease, which is considered in the lease term when it is reasonably certain that the Company will exercise any such options. Lease expense is recognized on a straight-line basis over the expected lease term and recorded in costs and expenses in the consolidated statements of operations. The Company has elected not to apply the recognition requirements of Accounting Standards Update (“ASU”) No. 2016-02 and No. 2018-10 (together “Topic 842”) for short-term leases. For lease agreements entered into by the Company that include lease and non-lease components, such components are generally accounted for separately.
Property and Equipment, net	Property and Equipment, net ​ Property and equipment are stated at cost, net of accumulated depreciation and amortization. The cost of property and equipment is depreciated or amortized on the straight-line method over the following estimated useful lives. The depreciation or amortization of capitalized construction in progress costs, a component of property and equipment, net, begins once the underlying asset is placed into service and is recognized over the estimated useful lives: ​ Computer equipment 2 years Computer software ​ 5 years Office furniture and equipment ​ 5 years Lab, process, and validation equipment ​ 5 years Machinery and equipment ​ 5 – 7 years Utility equipment ​ Lesser of the remaining economic life of the asset or the lease-term Leasehold improvements ​ Lesser of the remaining economic life of the asset or the lease-term ​ Expenditures for maintenance and repairs are charged to operations as incurred while renewals and betterments are capitalized. Gains and losses on disposals are included within operating expenses in the consolidated statements of operations. Management assesses the carrying value of property and equipment whenever events or changes in circumstances indicate that the carrying value may not be recoverable. If there is an indication of impairment, management prepares an estimate of future undiscounted cash flows expected to result from the use of the asset and its eventual disposition. If these cash flows are less than the carrying amount of the asset, an impairment loss is recognized to write down the asset to its estimated fair value. For the years ended December 31, 2024, 2023, and 2022, the Company did not recognize any impairments for its property and equipment.
Fair Value Measurements	Fair Value Measurements Under ASC Topic 820, Fair Value Measurements and Disclosures (“ASC 820”), fair value is defined as the price at which an asset could be exchanged, or a liability transferred in a transaction between knowledgeable, willing parties in the principal or most advantageous market for the asset or liability. Where available, fair value is based on observable market prices or parameters or derived from such prices or parameters. Where observable prices or parameters are not available, valuation models are applied. Assets and liabilities recorded at fair value in the Company’s financial statements are categorized based upon the level of judgment associated with the inputs used to measure their fair value. Hierarchical levels directly related to the amount of subjectivity associated with the inputs to fair valuation of these assets and liabilities, are as follows: - Level 1—These are investments where values are based on unadjusted quoted prices for identical assets in an active market that the Company has the ability to access. - Level 2—These are investments where values are based on quoted market prices in markets that are not active or model derived valuations in which all significant inputs are observable in active markets. - Level 3—These are financial instruments where values are derived from techniques in which one or more significant inputs are unobservable. The Company’s financial instruments consist of cash, cash equivalents, short-term investments, and long-term notes payable, all of which are reported at their respective fair value or approximate fair value on its consolidated balance sheets. A financial instrument’s categorization within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Where quoted prices are available in an active market, securities are classified as Level 1. ​ When quoted market prices are not available for a specific security, the Company estimates the fair value by using quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs obtained from various third-party data providers, including but not limited to, benchmark yields, interest rate curves, reported trades, broker/dealer quotes, and market reference data.
Revenue Recognition	Revenue Recognition The Company recognizes revenue from product sales in accordance with ASC Topic 606, Revenue from Contracts with Customers In the U.S., products are sold principally to hospitals and clinics, as well as distributors and wholesalers, and outside of the U.S. to hospitals and clinics. Contractual performance obligations are usually limited to transfer of control of the product to the customer. In the case of Amtagvi ® ® Revenue is reduced at the time of recognition for expected chargebacks, product returns, discounts, rebates, and sales allowances, collectively referred to as gross to net adjustments (“GTN adjustments”). In the U.S., these GTN adjustments are attributable to various commercial arrangements and government programs. In addition, non-U.S. government programs include different pricing schemes such as cost caps and volume discounts. Cash discounts are recorded as a reduction to receivables and settled through the issuance of credits, typically within one month. All other GTN adjustments are recorded as a liability and settled through cash payments to the customer. Significant judgment is required in estimating GTN adjustments considering legal interpretations of applicable laws and regulations, historical experience, payer channel mix, current contract prices under applicable programs, processing time lags and inventory levels in the distribution channel. Indirect taxes collected from customers and remitted to government authorities that are related to sales of the Company’s products, primarily in Europe, are excluded from revenues.
Stock-Based Compensation	Stock-Based Compensation The Company periodically grants stock options to employees and non-employees as compensation for services rendered. The Company accounts for all stock-based payment awards made to employees, including the employee stock purchase plans, and non-employees in accordance with the authoritative guidance provided by the Financial Accounting Standards Board (“FASB”) where the value of the award is measured on the date of grant and recognized over the vesting period. Forfeitures are recognized in the period in which they occur. The Company accounts for stock option grants to non-employees in a similar manner as stock option grants to employees except for the term used in the grant date fair value, therefore no longer requiring a re-measurement at the then-current fair values at each reporting date until the shares underlying the options have vested. The non-employee awards that contain a performance condition that affects the quantity or other terms of the award are measured based on the outcome that is probable. The fair value of the Company's common stock option grants is estimated using a Black-Scholes option pricing model, which uses certain assumptions related to risk-free interest rates, expected volatility, expected term of the common stock options, and future dividends. The stock-based compensation expense is recorded based upon the value derived from the Black-Scholes option pricing model. The assumptions used in the Black-Scholes option pricing model could affect compensation expense recorded in future periods. The Company issues restricted stock units (“RSUs”) from time to time as part of its equity incentive plans. The Company measures the compensation cost with respect to RSUs issued to employees based upon the estimated fair value of the equity instruments at the date of the grant, which is recognized as an expense over the period during which an employee is required to provide services in exchange for the awards. The fair value of RSUs is based on the closing price of the Company’s common stock on the grant date. In addition to RSUs that have time-based vesting requirements, from time to time the Company may issue RSUs that include certain performance vesting criteria based upon the satisfaction of stated objectives (“PRSUs”). The Company measures the compensation cost with respect to PRSUs issued to employees based upon the estimated fair value of the equity instruments at the date of grant, which is recognized as an expense over the period that achievement is determined to be probable through the stated service period associated with the award.
Accrued Research and Development Costs	Accrued Research and Development Costs Research and development costs are expensed as incurred. Clinical development costs compose a significant component of research and development costs. The Company has a history of contracting with third parties, including contract research organizations (“CROs”), independent clinical investigators, and contract manufacturing organizations (“CMOs”) that perform various clinical trial activities on the Company’s behalf in connection with the ongoing development of the Company’s product candidates. The financial terms of these contracts are subject to negotiations and may vary from contract to contract and may result in uneven payment flow. The Company accrues and expenses costs for clinical trial activities performed by third parties based upon the work completed to date for each clinical trial in accordance with agreements established with CROs, hospitals, and clinical investigators. Accruals for CROs and CMOs are recorded based on services received and efforts expended pursuant to agreements established with CROs, CMOs and other outside service providers. The Company determines its costs through discussions with internal clinical stakeholders and outside service providers as to the progress or stage of completion of clinical trials or services and the contracted fee to be paid for such services. ​ Included in the Company’s clinical development costs are investigator costs, which are costs associated with treatments administered at clinical sites as required under each clinical trial protocol. The Company’s determination of clinical investigator costs and related timing of expense recognition will depend on a number of factors that include, but are not limited to, (i) the overall number of patients that enroll in the trial at each individual site, (ii) the length of clinical trial enrollment period, (iii) discontinuation and completion rates of patients, (iv) duration of patient safety follow-ups, (v) the number of sites included in the clinical trial, and (vi) the contracted fee of each participating site for patient treatment while on clinical trial, which can vary greatly for several reasons including, but not limited to, geographic region, medical center or physician costs, and overhead costs. In addition, the Company’s estimates for per patient trial costs will vary based on a number of factors that include, but are not limited to, the extent of additional procedures that may be administered by investigators as a result of patient health status, recoverability of patient costs through insurance carriers of patients, and unanticipated cost of injuries incurred as a result of the clinical trial treatment. The Company accrues estimated expenses resulting from obligations under investigator site agreements as the timing of payments does not always timely align with the periods over which the treatments are administered by the clinical investigators. These estimates are typically based on contracted amounts, patient visit data, discussions with internal clinical stakeholders and outside service providers, and historical look-back analysis of actual payments made to date. ​ The Company makes judgements and estimates in determining the accrual balance in each reporting period. ​ In the event advance payments are made to a CRO, CMO or other outside service provider, the payments are recorded within prepaid expenses and other current assets in the Consolidated Balance Sheets and subsequently recognized as research and development expense in the consolidated statements of operations when the associated services have been performed. As actual costs become known, the Company adjusts its estimates, liabilities and assets. Inputs used in the determination of estimates discussed above may vary from actual, which will result in adjustments to research and development expense in future periods.
Selling, general and administrative expense	​ Selling, general, and administrative expense ​ Selling, general, and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in executive, finance, procurement, legal, investor relations, facilities, business development, marketing, commercial, information technology and human resources functions. Other significant costs include facility costs not otherwise included in research and development expenses. Selling, general, and administrative costs are expensed as incurred, and the Company accrues for services provided by third parties related to such expenses by monitoring the status of services provided and receiving estimates from its service providers and adjusting its accruals as actual costs become known.
Income Taxes	Income Taxes The Company accounts for income taxes using the asset and liability method whereby deferred tax assets and liabilities are recognized for the differences between the carrying amounts of existing assets and liabilities for financial reporting purposes and their respective tax bases. In addition, deferred tax assets are recorded for the future benefit of utilizing net operating losses and research and development credit carryforwards. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of changes in tax laws and rates on deferred tax assets and liabilities is recognized in income in the period of enactment. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some or all of the deferred tax assets will not be realized. The Company is required to use significant judgment in determining any valuation allowance recorded against its deferred tax assets. In assessing the need for a valuation allowance, the Company considers all available evidence, including scheduled reversal of deferred tax liabilities, past operating results, the feasibility of tax planning strategies and estimates of future taxable income. The Company bases its estimates of future taxable income on assumptions that are consistent with its operating plans, and such assumptions represent its best estimates and involve inherent uncertainties and the application of judgment. Should actual amounts differ from estimates, the amount of tax expense and liabilities recognized could be materially impacted. The Company recognizes the tax benefit from an uncertain tax position if it is more likely than not that the tax position will be sustained upon examination by the tax authorities, based on the merits of the position. The Company’s policy is to recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense or benefit. To date, there have been no interest or penalties incurred in relation to the unrecognized tax benefits.
Net Loss per Share	Net Loss per Share Basic net loss per share is computed by dividing the net loss by the weighted average number of common shares outstanding during the period. Diluted net loss per share is computed by dividing the net loss by the sum of the weighted average number of shares of common stock outstanding and the dilutive common stock equivalent outstanding during the period. The Company’s potentially dilutive common stock equivalent shares, which include incremental common shares issuable upon (i) the exercise of outstanding stock options, (ii) purchases through the 2020 Employee Stock Purchase Plan (the “2020 ESPP”), (iii) vesting of restricted stock units, and (vi) conversion of preferred stock, are only included in the calculation of diluted net loss per share when their effect is dilutive. As of December 31, 2024, 2023, and 2022, the following outstanding common stock equivalents have been excluded from the calculation of net loss per share because their impact would be anti-dilutive. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2024 2023 2022 Stock options ​ 18,218,126 18,899,849 15,240,197 Restricted stock units ​ 9,547,643 ​ 296,751 ​ 260,859 Employee Stock Purchase Plan ​ 239,366 ​ 3,453,901 ​ 2,436,764 Series A Convertible Preferred Stock* ​ 97,000 ​ 97,000 ​ 97,000 Series B Convertible Preferred Stock* ​ 2,842,158 2,842,158 2,842,158 ​ ​ 30,944,293 25,589,659 20,876,978 *on an as-converted basis The dilutive effect of potentially dilutive securities would be reflected in diluted earnings per common share by application of the treasury stock method. Under the treasury stock method, an increase in the fair market value of the Company's common stock could result in a greater dilutive effect from potentially dilutive securities.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of expenses during the reporting period. Actual results could differ from those estimates. Significant items subject to such estimates and assumptions include assumptions made in the fair value of intangible assets, inventories acquired as part of the acquisition of Proleukin ® , equity awards and related stock-based compensation, assumptions used in measuring operating right- of-use assets and operating lease liabilities, accounting for potential liabilities, including estimates inherent in accruals related to clinical trials, and the realizability of the Company’s deferred tax assets .
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include the accounts of Iovance Biotherapeutics, Inc. and its wholly-owned subsidiaries, Iovance Biotherapeutics Manufacturing LLC, Iovance Biotherapeutics GmbH, Iovance Biotherapeutics B.V ., Iovance Biotherapeutics UK Ltd, Iovance Biotherapeutics UK SP Ltd, Iovance Biotherapeutics Canada, Inc., and Iovance Australia Pty Ltd. All intercompany accounts and transactions have been eliminated.
Foreign Currency Translation	Foreign Currency Translation The consolidated financial statements are presented in U.S. dollars, which is the Company’s reporting currency. The assets and liabilities of the Company’s subsidiaries whose functional currencies are not in U.S. dollars are translated into U.S. dollars at the related period-end exchange rate. The U.S. dollar effects that arise from translation of net assets of these subsidiaries at changing rates are recognized in accumulated other comprehensive loss in the consolidated balance sheets. The subsidiaries’ net loss is translated into U.S. dollars by using the average exchange rate for the applicable period.
Segment Reporting	Segment Reporting The Company operates in one segment, focused on innovating, developing, and commercializing therapies using autologous TIL for patients with solid tumor cancers. Refer to Note 11 to the consolidated financial statements included in this Annual Report on Form 10-K for details.
Concentrations	Concentrations The Company is subject to credit risk from its portfolio of cash, cash equivalents and investments. Under its investment policy, the Company limits amounts invested in such securities by credit rating, maturity, industry group, investment type and issuer, except for securities issued by the U.S. government. The Company does not believe it is exposed to any significant concentrations of credit risk from these financial instruments. The Company maintains cash, cash equivalents and investment balances at three financial institutions. Management believes that the financial institutions which hold its cash are financially sound and, accordingly, minimal credit risk exists. As of December 31, 2024 and 2023, respectively, the Company’s cash balances were in excess of insured limits maintained at the financial institutions.
Recent Accounting Standards	Recent Accounting Standards In November 2023, FASB issued Accounting Standard Update (“ASU”) ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, which enhances the disclosures required for operating segments in annual and interim consolidated financial statements. ASU 2023-07 was effective for us in our annual reporting starting in fiscal year 2024 and for interim period reporting beginning in fiscal year 2025 on a retrospective basis. The Company adopted ASU 2023-07 as of December 31, 2024, and the enhanced disclosures as required are included in Note 11 – Segments. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which requires public entities, on an annual basis, to provide disclosure of specific categories in the rate reconciliation, as well as disclosure of income taxes paid disaggregated by jurisdiction. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024 on a prospective basis. Early adoption and retrospective reporting are permitted. The Company is currently evaluating the impact of ASU 2023-09 on its consolidated financial statements. In November 2024, the FASB issued ASU 2024-03, Income Statement-Reporting Comprehensive Income-Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses, which requires the disaggregation of certain expense captions into specified categories in disclosures within the notes to the financial statements to provide enhanced transparency into the expense captions presented on the face of the income statement. ASU 2024-03 is effective for annual reporting periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027, with early adoption permitted, and may be applied either prospectively or retrospectively to financial statements issued for reporting periods after the effective date of ASU 2024-03 or retrospectively to any or all prior periods presented in the financial statements. The Company is currently evaluating the impact of adopting ASU 2024-03.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2024
SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES
Schedule of cash and cash equivalents and restricted cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the consolidated balance sheets that sum to the total of the same such amounts shown in the consolidated statements of cash flows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ ​ ​ 2024 ​ 2023 ​ 2022 Cash and cash equivalents ​ $ 115,694 ​ $ 114,888 ​ $ 231,731 Restricted cash ​ 6,359 ​ 66,430 ​ 6,430 Total cash, cash equivalents and restricted cash ​ $ 122,053 ​ $ 181,318 ​ $ 238,161
Schedule Of Useful Lives Of Property Plant And Equipment	​ Computer equipment 2 years Computer software ​ 5 years Office furniture and equipment ​ 5 years Lab, process, and validation equipment ​ 5 years Machinery and equipment ​ 5 – 7 years Utility equipment ​ Lesser of the remaining economic life of the asset or the lease-term Leasehold improvements ​ Lesser of the remaining economic life of the asset or the lease-term
Schedule of Antidilutive securities excluded from computation of earnings per share	As of December 31, 2024, 2023, and 2022, the following outstanding common stock equivalents have been excluded from the calculation of net loss per share because their impact would be anti-dilutive. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2024 2023 2022 Stock options ​ 18,218,126 18,899,849 15,240,197 Restricted stock units ​ 9,547,643 ​ 296,751 ​ 260,859 Employee Stock Purchase Plan ​ 239,366 ​ 3,453,901 ​ 2,436,764 Series A Convertible Preferred Stock* ​ 97,000 ​ 97,000 ​ 97,000 Series B Convertible Preferred Stock* ​ 2,842,158 2,842,158 2,842,158 ​ ​ 30,944,293 25,589,659 20,876,978 *on an as-converted basis

CASH EQUIVALENTS AND INVESTME_2

CASH EQUIVALENTS AND INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2024
CASH EQUIVALENTS AND INVESTMENTS
Schedule of cost and fair value of cash equivalents and short-term investments	The amortized cost and fair value of cash equivalents and investments as of December 31, 2024 and December 31, 2023 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ As of December 31, 2024 Cost Gains Losses Fair Value U.S. treasury securities ​ $ 207,970 ​ $ 117 ​ $ — ​ $ 208,087 Money market funds ​ ​ 61,432 ​ ​ — ​ ​ — ​ ​ 61,432 Total investments ​ $ 269,402 ​ $ 117 ​ $ — ​ $ 269,519 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross ​ Gross ​ ​ ​ ​ ​ Amortized ​ Unrealized ​ Unrealized ​ ​ ​ As of December 31, 2023 Cost Gains Losses Fair Value U.S. treasury securities ​ $ 164,940 ​ $ 39 ​ $ — ​ $ 164,979 Money market funds ​ ​ 34,053 ​ ​ — ​ ​ — ​ ​ 34,053 Total investments ​ $ 198,993 ​ $ 39 ​ $ — ​ $ 199,032
Schedule of available-for-sale debt securities	The fair value of cash equivalents and investments as of December 31, 2024 and December 31, 2023 are classified as follows in the Company’s consolidated balance sheets (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, Classified as: ​ 2024 2023 Cash equivalents ​ $ 61,432 ​ $ 34,053 Short-term investments ​ ​ 208,087 ​ ​ 164,979 Total investments ​ $ 269,519 ​ $ 199,032
Schedule of fair value of the company's financial assets	As of December 31, 2024 and 2023, the fair value of the Company’s financial assets that are measured at fair value on a recurring basis, which consist of cash equivalents and short-term and long-term investments classified as available-for-sale securities, are categorized in the table below based upon the lowest level of significant input to the valuations (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets at Fair Value as of December 31, 2024 ​ Level 1 Level 2 Level 3 Total U.S. treasury securities ​ $ 208,087 ​ $ — ​ $ — ​ $ 208,087 Money market funds ​ ​ 61,432 ​ ​ — ​ ​ — ​ ​ 61,432 Total investments ​ $ 269,519 ​ $ — ​ $ — ​ $ 269,519 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Assets at Fair Value as of December 31, 2023 ​ Level 1 Level 2 Level 3 Total U.S. treasury securities ​ $ 164,979 ​ $ — ​ $ — ​ $ 164,979 Money market funds ​ ​ 34,053 ​ ​ — ​ ​ — ​ ​ 34,053 Total ​ $ 199,032 ​ $ — ​ $ — ​ $ 199,032 ​

PROLEUKIN ACQUISITION (Tables)

PROLEUKIN ACQUISITION (Tables)	12 Months Ended
	Dec. 31, 2024
PROLEUKIN ACQUISITION
Summary of the total cash consideration and allocated acquisition date fair values of assets acquired and liabilities assumed	The following table summarizes the total cash consideration and allocated acquisition date fair values of assets acquired and liabilities assumed at the time of the acquisition (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ Amounts Cash ​ $ 35 Inventory ​ ​ 9,688 Developed technology ​ ​ 232,665 Assembled workforce ​ ​ 636 Deferred tax liability ​ ​ (20,352) Total Cost of Acquisition ​ $ 222,672 ​

INTANGIBLE ASSETS, NET (Tables)

INTANGIBLE ASSETS, NET (Tables)	12 Months Ended
	Dec. 31, 2024
INTANGIBLE ASSETS, NET
Summary of gross carrying amounts and net book value of intangible assets	The gross carrying amounts and net book value of intangible assets as of December 31, 2024 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ 2024 ​ 2023 Developed technology ​ $ 304,939 ​ $ 238,612 Assembled workforce ​ ​ 643 ​ ​ 652 Intellectual property license ​ ​ 7,500 ​ ​ — Total intangible assets ​ $ 313,082 ​ $ 239,264 Less: accumulated amortization ​ ​ (30,684) ​ ​ (10,006) Intangible assets, net ​ $ 282,398 ​ $ 229,258

INVENTORY (Tables)

INVENTORY (Tables)	12 Months Ended
	Dec. 31, 2024
INVENTORY
Summary of inventories	As of December 31, 2024 and December 31, 2023, inventory consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ December 31, ​ ​ ​ 2024 ​ ​ 2023 Raw materials ​ $ 27,743 ​ $ — Work in process ​ ​ 8,765 ​ ​ 5,749 Finished goods ​ ​ 15,012 ​ ​ 4,623 Total inventory ​ $ 51,520 ​ $ 10,372 ​

REVENUE (Tables)

REVENUE (Tables)	12 Months Ended
	Dec. 31, 2024
REVENUE
Schedule of disaggregation of revenue by product	Net revenue for the periods presented represents sales of Amtagvi ® ® ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ ​ 2024 ​ ​ 2023 ​ ​ 2022 Amtagvi ® ​ $ 103,567 ​ $ — ​ $ — Proleukin ® ​ ​ 60,503 ​ ​ 1,189 ​ ​ — Total net revenue ​ $ 164,070 ​ $ 1,189 ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ 2024 ​ ​ 2023 ​ ​ 2022 Gross revenue ​ $ 169,170 ​ $ 1,192 ​ $ — GTN adjustments: ​ ​ ​ ​ ​ ​ ​ ​ ​ Government rebates and chargebacks ​ ​ (172) ​ ​ — ​ ​ — Wholesaler fees and cash discounts ​ ​ (3,226) ​ ​ (3) ​ ​ — Other rebates, returns, discounts and adjustments ​ ​ (1,702) ​ ​ — ​ ​ — Total GTN adjustments ​ (5,100) ​ (3) ​ — Net revenue ​ $ 164,070 ​ $ 1,189 ​ $ —
Schedule of GTN adjustments recorded in revenue	Revenue from product sales was recorded net of GTN adjustments. The following table summarizes GTN adjustments for the periods presented (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ 2024 ​ ​ 2023 ​ ​ 2022 Gross revenue ​ $ 169,170 ​ $ 1,192 ​ $ — GTN adjustments: ​ ​ ​ ​ ​ ​ ​ ​ ​ Government rebates and chargebacks ​ ​ (172) ​ ​ — ​ ​ — Wholesaler fees and cash discounts ​ ​ (3,226) ​ ​ (3) ​ ​ — Other rebates, returns, discounts and adjustments ​ ​ (1,702) ​ ​ — ​ ​ — Total GTN adjustments ​ (5,100) ​ (3) ​ — Net revenue ​ $ 164,070 ​ $ 1,189 ​ $ — ​ ​ Consolidated net product revenue by geographic area for the periods presented is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ ​ 2024 ​ ​ 2023 ​ ​ 2022 United States ​ $ 161,043 ​ $ — ​ $ — Rest of world ​ ​ 3,027 ​ ​ 1,189 ​ ​ — Net revenue ​ $ 164,070 ​ $ 1,189 ​ $ —
Schedule of the amount and percentage of gross revenue attributable to customers that represented more than 10% of the Company's gross revenue and all other customers as a group	The following table summarizes the amount and percentage of gross revenue attributable to customers that represented more than 10% of the Company’s gross revenue and all other customers as a group for the years ended December 31, 2024 and December 31, 2023, respectively (in thousands, except percentages): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2024 ​ Year Ended December 31, 2023 ​ ​ ​ $ ​ ​ % ​ ​ $ ​ ​ % Customer A ​ $ 28,395 ​ ​ 17% ​ $ — ​ ​ 0% Other customers ​ ​ 140,775 ​ ​ 83% ​ ​ 1,192 ​ ​ 100% Gross revenue ​ $ 169,170 ​ ​ 100% ​ $ 1,192 ​ ​ 100% GTN adjustments ​ ​ (5,100) ​ ​ ​ ​ ​ (3) ​ ​ ​ Net revenue ​ $ 164,070 ​ ​ ​ ​ $ 1,189 ​ ​ ​ ​

PROPERTY AND EQUIPMENT, NET (Ta

PROPERTY AND EQUIPMENT, NET (Tables)	12 Months Ended
	Dec. 31, 2024
PROPERTY AND EQUIPMENT, NET
Schedule of Property and equipment	Property and equipment, net consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2024 2023 Leasehold improvements ​ $ 67,375 ​ $ 76,804 Lab, process, and validation equipment ​ ​ 25,477 ​ ​ 23,131 Utility equipment ​ 5,990 ​ 5,990 Office furniture and equipment ​ 1,998 ​ 3,297 Computer software ​ ​ 8,512 ​ ​ 7,772 Computer equipment ​ 448 ​ 542 Machinery and equipment ​ ​ 363 ​ ​ 306 Construction in progress ​ 34,938 ​ 24,101 Total property and equipment, cost ​ $ 145,101 ​ $ 141,943 Less: Accumulated depreciation and amortization ​ (36,020) ​ (27,913) Property and equipment, net ​ $ 109,081 ​ $ 114,030

ACCRUED EXPENSES (Tables)

ACCRUED EXPENSES (Tables)	12 Months Ended
	Dec. 31, 2024
ACCRUED EXPENSES
Schedule of accrued expenses	Accrued expenses consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ 2024 2023 Accrued payroll and employee related expenses ​ $ 31,910 ​ $ 34,814 Clinical related ​ ​ 13,017 ​ ​ 10,911 Manufacturing related ​ 10,084 ​ 10,893 Facilities related ​ ​ 6,748 ​ ​ 2,437 Legal and related services ​ 2,466 ​ 1,610 Inventory and distribution related ​ ​ 12,471 ​ ​ 2,148 Other accrued expenses ​ 5,240 ​ 6,593 Total accrued expenses ​ $ 81,936 ​ $ 69,406 ​

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	12 Months Ended
	Dec. 31, 2024
STOCKHOLDERS' EQUITY
Schedule of status of stock options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ Aggregate ​ ​ Number ​ Average ​ Remaining ​ Intrinsic ​ ​ of ​ Exercise ​ Contract ​ Value ​ Options Price Life (Years) ( in thousands) Outstanding at December 31, 2023 ​ 18,899,849 ​ $ 18.57 ​ ​ ​ $ ​ Issued ​ 1,731,325 ​ 9.72 ​ ​ ​ ​ ​ Exercised ​ (425,925) ​ 7.67 ​ ​ ​ ​ ​ Expired/Cancelled ​ (1,987,123) ​ 23.78 ​ ​ ​ ​ ​ Outstanding at December 31, 2024 ​ 18,218,126 $ 17.41 6.26 ​ $ 2,550 Ending vested and expected to vest at December 31, 2024 ​ 18,218,126 ​ $ 17.41 ​ 6.26 ​ $ 2,550 Options exercisable at December 31, 2024 14,137,830 ​ $ 19.96 5.56 ​ $ 1,527
Schedule of summary of RSU activity including PRSUs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Number ​ Average ​ ​ of ​ Grant Date ​ RSUs and PRSUs Fair Value Outstanding at December 31, 2023 ​ 3,453,901 ​ $ 8.97 Granted ​ 9,924,555 ​ ​ 16.53 Vested/Released ​ (3,150,172) ​ ​ 12.95 Canceled/Forfeited ​ (680,641) ​ ​ 15.09 Outstanding at December 31, 2024 ​ 9,547,643 ​ $ 15.08 Ending vested and expected to vest at December 31, 2024 ​ 9,547,643 ​ $ 15.08
Schedule of stock-based compensation	Total stock-based compensation expense related to the Company’s stock-based awards was recorded on the consolidated statements of operations as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ 2024 2023 2022 Cost of sales ​ $ 8,554 ​ $ — ​ $ — Research and development ​ ​ 49,270 ​ ​ 34,926 ​ ​ 50,242 Selling, general, and administrative ​ 51,799 ​ 27,699 ​ 33,780 Total stock-based compensation expense ​ $ 109,623 ​ $ 62,625 ​ $ 84,022
Schedule of stock-based compensation by type of award	Total stock-based compensation expense by type of award was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ ​ 2024 2023 2022 Stock option expense ​ $ 21,112 ​ $ 45,340 ​ $ 58,308 Restricted stock expense ​ 87,025 ​ 16,062 ​ 24,436 ESPP expense ​ 1,486 ​ 1,223 ​ 1,278 Total stock-based compensation expense ​ $ 109,623 ​ $ 62,625 ​ $ 84,022
Schedule of share-based payment award, stock options, valuation assumptions	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock Options ​ ESPP ​ ​ Years Ended December 31, ​ Years Ended December 31, Assumptions: 2024 2023 2022 2024 2023 2022 Expected term (years) ​ 5.41 - 5.56 5.18 - 5.37 4.94 - 5.12 ​ 0.50 ​ 0.5 ​ 0.50 Expected volatility ​ 85.03% - 85.85% 83.63% - 84.21% 73.73% - 83.90% ​ 73.85% - 98.85% ​ 72.96% - 83.36% ​ 73.02% - 137.42% Risk-free interest rate ​ 3.61% - 4.33% ​ 3.59% - 4.60% ​ 1.25% - 4.05% ​ 4.35% - 5.40% ​ 5.38% - 5.40% ​ 1.98% - 4.78% Expected dividend yield ​ 0% ​ 0% ​ 0% ​ 0% ​ 0% ​ 0%

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2024
SEGMENT INFORMATION
Summary of company's revenue, expenses and net loss for the segment and is reconciled to net loss on a consolidated basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ Increase (Decrease) (in thousands) 2024 2023 ​ $ % Net sales $ 164,070 ​ $ 1,189 ​ 162,881 ​ 13,698 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Direct cost of goods sold (a) $ 83,637 ​ $ 663 ​ ​ ​ ​ Acquisition related cost of sales (b) $ 26,161 ​ $ 10,092 ​ ​ ​ ​ Royalties $ 14,197 ​ $ - ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total cost of sales $ 123,995 ​ $ 10,755 ​ 113,240 ​ 1,053 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expenses ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development $ 200,361 ​ $ 278,032 ​ (77,671) ​ (27.9) General and administrative $ 97,153 ​ $ 88,960 ​ 8,193 ​ 9.2 Sales and marketing $ 26,986 ​ $ 21,376 ​ 5,610 ​ 26.2 Other segment items (c) $ 87,752 ​ $ 46,104 ​ 41,648 ​ 90.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total expenses $ 412,252 ​ $ 434,471 ​ (22,220) ​ (5.1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net loss $ (372,177) ​ $ (444,037) ​ (71,860) ​ (16.2) ​ ​ ​ a) Direct cost of goods sold represents inventory and period costs related to overhead and manufacturing costs of Amtagvi® as well as costs associated with the purchases and sales of Proleukin ® ® b) Acquisition related cost of sales represents amortization expenses for the developed technology intangible assets and the milestone payment recorded as part of the acquisition of Proleukin ® c) Other segment items include costs that are not considered significant expense segments nor reviewed by the CODM on a regular basis. Such amount includes stock-based compensation expenses, interest income, other income and expenses, and income tax benefits. ​

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2024
INCOME TAXES
Schedule of Deferred Tax Assets and Liabilities	The significant components of the Company’s net deferred tax assets and liabilities are summarized as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2024 2023 Deferred income tax assets: ​ ​ Net operating loss carryforwards ​ $ 302,875 ​ $ 255,639 Stock-based compensation ​ 40,909 ​ 28,609 Tax credit carryforwards ​ 66,874 ​ 58,565 Lease liabilities ​ ​ 14,759 ​ ​ 16,024 Capitalized R&D ​ ​ 137,577 ​ ​ 99,107 Reserves and accruals ​ 11,523 ​ 6,540 Deferred tax assets before valuation allowance ​ 574,517 ​ 464,484 Less: valuation allowance ​ (557,587) ​ (446,853) Net deferred income tax assets ​ 16,930 ​ 17,631 Deferred tax liabilities: ​ ​ ​ ​ Right-of-use assets ​ ​ (14,228) ​ ​ (13,381) Depreciation and amortization ​ (35,017) ​ (21,597) Net deferred tax assets (liabilities) ​ $ (32,315) ​ $ (17,347)
Schedule of Effective Income Tax Rate Reconciliation	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years ended December 31, ​ 2024 2023 2022 Federal statutory tax rate 21 % 21 % 21 % Orphan drug and research credits 2 2 1 ​ Permanent and other differences (2) (1) (1) ​ Stock-based compensation (1) (1) (1) ​ State tax, net of federal benefit 10 1 1 ​ ​ 30 % 22 % 21 % Valuation allowance (29) % (21) % (21) % Effective tax rate 1 % 1 % — %
Schedule of Unrecognized Tax Benefits	A reconciliation of the beginning and ending balances of the unrecognized tax benefits during the years ended December 31, 2024, 2023 and 2022 is as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ 2024 2023 2022 Unrecognized benefit - beginning of period ​ $ 26,107 ​ $ 21,645 ​ $ 18,171 Gross decreases - prior period tax positions ​ — ​ — ​ — Gross increases - current period tax positions ​ 3,747 ​ 4,462 ​ 3,474 Unrecognized benefit - end of period ​ $ 29,854 ​ $ 26,107 ​ $ 21,645

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2024
LEASES
Schedule of balance sheet classification of the Company's right-of-use asset and lease liabilities	The balance sheet classification of the Company’s right-of-use asset and lease liabilities was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, ​ ​ 2024 ​ 2023 Operating lease right-of-use assets $ 55,201 $ 62,515 Operating lease liabilities ​ ​ Current portion included in current liabilities ​ 12,896 ​ 7,777 Long-term portion included in non-current liabilities ​ 44,365 ​ 67,085 Total operating lease liabilities ​ $ 57,261 ​ $ 74,862
Schedule of components of lease expenses	The following table summarizes components of lease expenses, which were included in total expenses in the Company’s consolidated statements of operations and in inventory in the consolidated balance sheets, and other information related to the Company’s operating leases as follows (in thousands, except weighted-average remaining lease terms and discount rates): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year ​ For the Year ​ ​ Ended ​ Ended ​ December 31, 2024 December 31, 2023 Operating lease cost ​ $ 16,484 ​ $ 17,786 ​ Variable lease cost ​ ​ 3,995 ​ 7,629 ​ Short-term lease cost ​ ​ 431 ​ 335 ​ Total lease cost ​ $ 20,910 ​ $ 25,750 ​ ​ ​ ​ ​ ​ ​ ​ ​ Other information ​ ​ ​ ​ ​ ​ ​ Cash paid for amounts included in the measurement of lease liabilities included in cash flows from operations ​ $ 18,120 ​ $ 16,871 ​ Right-of-use assets obtained from entering new leases ​ $ 2,306 ​ $ 177 ​ Increase in right-of-use assets from lease modifications ​ $ 818 ​ $ 1,033 ​ Weighted-average remaining lease terms (years) ​ ​ 12.83 ​ ​ 13.09 ​ Weighted-average discount rates ​ ​ 7.9 % ​ 7.4 % ​
Schedule of minimum lease commitments	As of December 31, 2024, maturities of the Company's operating lease liabilities were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CMO ​ ​ ​ ​ Facility ​ embedded ​ ​ ​ Year Ending December 31, ​ leases leases Total 2025 ​ $ 6,039 ​ $ 10,910 ​ $ 16,949 2026 ​ 5,452 ​ — ​ 5,452 2027 ​ 4,307 ​ — ​ 4,307 2028 ​ 4,393 ​ — ​ 4,393 2029 ​ 4,481 ​ — ​ 4,481 Thereafter ​ 57,496 ​ — ​ 57,496 Total lease payments ​ $ 82,168 ​ $ 10,910 ​ $ 93,078 Less: Present value adjustment ​ (35,179) ​ (638) ​ (35,817) Operating lease liabilities ​ $ 46,989 ​ $ 10,272 ​ $ 57,261

GENERAL ORGANIZATION, BUSINES_2

GENERAL ORGANIZATION, BUSINESS AND LIQUIDITY (Details) $ in Thousands		12 Months Ended
	Feb. 14, 2025 USD ($)	Dec. 31, 2024 USD ($) item	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Cash, cash equivalents, short-term investments, and restricted cash		$ 330,100
Cash and cash equivalents		115,694	$ 114,888	$ 231,731
Short-term investments		208,087	164,979
Restricted cash		6,359	66,430	6,430
Net Loss		372,177	444,037	395,893
Net cash used in operating activities		$ (352,977)	$ (361,820)	$ (292,757)
Minimum | Amtagvi
Number of patients to be treated annually | item		20,000
Subsequent Event
Proceeds from Issuance of sale	$ 122,300

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES - Cash, Cash equivalents and Restricted Cash (Details) $ in Thousands, £ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2024 GBP (£)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Impairment losses related to credit losses			$ 0	$ 0	$ 0
Restricted security deposit			5,450
Cash and cash equivalents			115,694	114,888	231,731
Restricted cash (current and long-term)			6,359	66,430	6,430
Total cash, cash equivalents and restricted cash			122,053	$ 181,318	$ 238,161	$ 84,313
PROLEUKIN
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Future milestone payment			$ 60,000
Contingent consideration paid for acquisition	$ 52,600	£ 41.7
Minimum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Customer payment term			45 days
Maximum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Customer payment term			105 days
Commercial manufacturing facility
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Decrease in letters of credit			$ 1,000
Restricted cash (current and long-term)			5,450
Commercial manufacturing facility | Minimum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Security deposit			1,500
Headquarters lease
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Security deposit			$ 600

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES - Useful lives, impairment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2022
Impairment of Long-Lived Assets Held-for-use	$ 7,355	$ 397
Computer equipment
Property, Plant and Equipment, Useful Life	2 years
Computer software
Property, Plant and Equipment, Useful Life	5 years
Office furniture and equipment
Property, Plant and Equipment, Useful Life	5 years
Lab, process, and validation equipment
Property, Plant and Equipment, Useful Life	5 years
Machinery and equipment | Minimum
Property, Plant and Equipment, Useful Life	5 years
Machinery and equipment | Maximum
Property, Plant and Equipment, Useful Life	7 years
Utility equipment
Property, Plant and Equipment, Estimated Useful Lives	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember
Leasehold improvements
Property, Plant and Equipment, Estimated Useful Lives	us-gaap:UsefulLifeShorterOfTermOfLeaseOrAssetUtilityMember

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES - Net Loss per Share (Details) - shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Antidilutive securities excluded from calculation of net loss per share	30,944,293	25,589,659	20,876,978
Employee Stock Option
Antidilutive securities excluded from calculation of net loss per share	18,218,126	18,899,849	15,240,197
Restricted stock units
Antidilutive securities excluded from calculation of net loss per share	9,547,643	296,751	260,859
Employee Stock Purchase Plan
Antidilutive securities excluded from calculation of net loss per share	239,366	3,453,901	2,436,764
Series A Convertible Preferred Stock
Antidilutive securities excluded from calculation of net loss per share	97,000	97,000	97,000
Series B Convertible Preferred Stock | Restricted stock units
Antidilutive securities excluded from calculation of net loss per share	2,842,158	2,842,158	2,842,158

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES - Income taxes & Segment Reporting (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) item segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
SUMMARY OF SIGNIFICANT ACCOUNTING PRACTICES
Number of operating segments | segment	1
Number Of Financial Institutions | item	3
Interest and penalties | $	$ 0	$ 0	$ 0

CASH EQUIVALENTS AND INVESTME_3

CASH EQUIVALENTS AND INVESTMENTS - Cost and fair value (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Amortized Cost	$ 269,402	$ 198,993
Gross Unrealized Gains	117	39
Fair Value	269,519	199,032
U.S. treasury securities
Amortized Cost	207,970	164,940
Gross Unrealized Gains	117	39
Fair Value	208,087	164,979
Money market funds
Amortized Cost	61,432	34,053
Fair Value	$ 61,432	$ 34,053

CASH EQUIVALENTS AND INVESTME_4

CASH EQUIVALENTS AND INVESTMENTS - Available for sale debt securities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
CASH EQUIVALENTS AND INVESTMENTS
Cash equivalents	$ 61,432	$ 34,053
Short-term investments	208,087	164,979
Total investments	$ 269,519	$ 199,032

CASH EQUIVALENTS AND INVESTME_5

CASH EQUIVALENTS AND INVESTMENTS - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Cash equivalents total	$ 61,432	$ 34,053
Unrealized losses on available-for-sale	$ 0	$ 0
Number of investments in debt securities in continuous unrealized loss position for more than 12 months	0	0
Demand Deposits
Cash equivalents total	$ 54,300	$ 80,800

CASH EQUIVALENTS AND INVESTME_6

CASH EQUIVALENTS AND INVESTMENTS - Fair value of company's financial assets (Details) - Recurring - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Total	$ 269,519	$ 199,032
U.S. treasury securities
Total	208,087	164,979
Money market funds
Total	61,432	34,053
Level 1
Total	269,519	199,032
Level 1 | U.S. treasury securities
Total	208,087	164,979
Level 1 | Money market funds
Total	$ 61,432	$ 34,053

PROLEUKIN ACQUISITION - Narrati

PROLEUKIN ACQUISITION - Narrative (Details) - PROLEUKIN £ in Millions, $ in Millions			12 Months Ended
	May 18, 2023 GBP (£)	May 18, 2023 USD ($)	Dec. 31, 2024 USD ($)
PROLEUKIN ACQUISITION
Upfront payment	£ 166.9	$ 207.2	$ 210.2
Payment for certain inventory	£ 2.4	$ 3

PROLEUKIN ACQUISITION - Cash co

PROLEUKIN ACQUISITION - Cash consideration and allocated fair value of assets acquired and liability assumed (Details) - PROLEUKIN - USD ($) $ in Thousands		12 Months Ended
	May 18, 2023	Dec. 31, 2024
Total cash consideration and allocated acquisition date fair values of assets acquired and liabilities assumed
Cash	$ 35
Inventory	9,688
Deferred tax liability	(20,352)
Total Cost of Acquisition	222,672	$ 222,700
Developed technology
Total cash consideration and allocated acquisition date fair values of assets acquired and liabilities assumed
Intangible assets	232,665
Assembled workforce
Total cash consideration and allocated acquisition date fair values of assets acquired and liabilities assumed
Intangible assets	$ 636

PROLEUKIN ACQUISITION - Additio

PROLEUKIN ACQUISITION - Additional information (Details) $ in Thousands, £ in Millions			3 Months Ended		12 Months Ended
	May 18, 2023 USD ($)	May 18, 2023 GBP (£)	Mar. 31, 2024 USD ($)	Mar. 31, 2024 GBP (£)	Dec. 31, 2024 USD ($)
PROLEUKIN ACQUISITION
Finite-lived intangible assets			$ 17,500	£ 13.9
PROLEUKIN
PROLEUKIN ACQUISITION
Total cost of acquisition	$ 222,672				$ 222,700
Cash payment	207,200	£ 166.9			210,200
Direct transaction costs incurred					$ 12,500
Contingent cash payments, milestone payment	$ 50,000	£ 41.7
Deferred consideration term	12 years	12 years
Contingent consideration paid for acquisition			$ 52,600	£ 41.7
PROLEUKIN | Developed technology
PROLEUKIN ACQUISITION
Expected useful life of intangible assets	15 years	15 years
Weighted average amortization period					14 years 9 months 18 days
PROLEUKIN | Assembled workforce
PROLEUKIN ACQUISITION
Weighted average amortization period					14 years 9 months 18 days
PROLEUKIN | Assembled workforce | Selling, general and administrative
PROLEUKIN ACQUISITION
Expected useful life of intangible assets	3 years	3 years

INTANGIBLE ASSETS, NET (Details

INTANGIBLE ASSETS, NET (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Gross carrying amounts and net book value of intangible assets
Gross carrying amounts	$ 313,082	$ 239,264
Less: accumulated amortization	(30,684)	(10,006)
Intangible assets, net	282,398	229,258
Amortization expense	21,202	9,849
Total estimated amortization of the Company's intangible assets:
Year ending December 31, 2025	21,500
Year ending December 31, 2026	21,400
Year ending December 31, 2027	21,300
Year ending December 31, 2028	21,300
Years ending December 31, 2029	21,300
Developed technology
Gross carrying amounts and net book value of intangible assets
Gross carrying amounts	304,939	238,612
Assembled workforce
Gross carrying amounts and net book value of intangible assets
Gross carrying amounts	643	$ 652
Intellectual property license
Gross carrying amounts and net book value of intangible assets
Gross carrying amounts	$ 7,500

INVENTORY (Details)

INVENTORY (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
INVENTORY
Raw materials	$ 27,743
Work in process	8,765	$ 5,749
Finished goods	15,012	4,623
Total inventory	$ 51,520	$ 10,372

REVENUE (Details)

REVENUE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
REVENUE
Total net revenue	$ 164,070	$ 1,189
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Amtagvi
REVENUE
Total net revenue	$ 103,567
Proleukin
REVENUE
Total net revenue	$ 60,503	$ 1,189

REVENUE - GTN Adjustments (Deta

REVENUE - GTN Adjustments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
REVENUE
Gross revenue	$ 169,170	$ 1,192
GTN adjustments:
Government rebates and chargebacks	(172)
Wholesaler fees and cash discounts	(3,226)	(3)
Other rebates, returns, discounts and adjustments	(1,702)
Total GTN adjustments	(5,100)	(3)
Net revenue	$ 164,070	$ 1,189
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember

REVENUE - Consolidated net prod

REVENUE - Consolidated net product revenue by geographic area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
REVENUE
Total net revenue	$ 164,070	$ 1,189
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Threshold for concentration of credit risk	10%	10%
United States
REVENUE
Total net revenue	$ 161,043
Rest of world
REVENUE
Total net revenue	$ 3,027	$ 1,189

REVENUE - Concentration (Detail

REVENUE - Concentration (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Summary of the amount and percentage of gross revenue attributable to customers that represented more than 10% of the Company's gross revenue and all other customers as a group
Gross revenue	$ 169,170	$ 1,192
GTN adjustments	(5,100)	(3)
Total net revenue	$ 164,070	$ 1,189
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Revenue | Customer concentration
Summary of the amount and percentage of gross revenue attributable to customers that represented more than 10% of the Company's gross revenue and all other customers as a group
Gross revenue	$ 169,170	$ 1,192
Concentration risk (in percent)	100%	100%
Revenue | Customer concentration | Customer A
Summary of the amount and percentage of gross revenue attributable to customers that represented more than 10% of the Company's gross revenue and all other customers as a group
Gross revenue	$ 28,395
Concentration risk (in percent)	17%	0%
Revenue | Customer concentration | Other customers
Summary of the amount and percentage of gross revenue attributable to customers that represented more than 10% of the Company's gross revenue and all other customers as a group
Gross revenue	$ 140,775	$ 1,192
Concentration risk (in percent)	83%	100%

PROPERTY AND EQUIPMENT, NET - (

PROPERTY AND EQUIPMENT, NET - (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	$ 145,101	$ 141,943
Less: Accumulated depreciation and amortization	(36,020)	(27,913)
Property and equipment, net	109,081	114,030
Leasehold improvements
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	67,375	76,804
Lab, process, and validation equipment
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	25,477	23,131
Utility equipment
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	5,990	5,990
Office furniture and equipment
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	1,998	3,297
Computer software
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	8,512	7,772
Computer equipment
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	448	542
Machinery and equipment
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	363	306
Construction in progress
PROPERTY AND EQUIPMENT, NET
Total property and equipment, cost	$ 34,938	$ 24,101

PROPERTY AND EQUIPMENT, NET - O

PROPERTY AND EQUIPMENT, NET - Other information (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 15, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
PROPERTY AND EQUIPMENT, NET
Depreciation and amortization expense		$ 11,967	$ 11,568	$ 9,310
New Headquarters Lease | San Carlos, California | Office Space
PROPERTY AND EQUIPMENT, NET
Impairment due to early termination	$ 7,400	$ 7,400

ACCRUED EXPENSES (Details)

ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
ACCRUED EXPENSES
Accrued payroll and employee related expenses	$ 31,910	$ 34,814
Clinical related	13,017	10,911
Manufacturing related	10,084	10,893
Facilities related	6,748	2,437
Legal and related services	2,466	1,610
Inventory and distribution related	12,471	2,148
Other accrued expenses	5,240	6,593
Total accrued expenses	$ 81,936	$ 69,406

STOCKHOLDERS' EQUITY (Details)

STOCKHOLDERS' EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands						12 Months Ended
	Feb. 14, 2025	Feb. 22, 2024	Jul. 13, 2023	Nov. 18, 2022	Jun. 08, 2020	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Nov. 22, 2024	Nov. 21, 2024	Jun. 11, 2024	Feb. 26, 2024	Feb. 25, 2024	Jun. 16, 2023	Jun. 06, 2023	Jun. 05, 2023	Mar. 13, 2023	Mar. 12, 2023	Jun. 10, 2022	Jan. 12, 2022	Jan. 11, 2022	Sep. 22, 2021	Apr. 22, 2018
STOCKHOLDERS' EQUITY
Common stock, shares authorized						500,000,000	500,000,000
Common stock, par or stated value per share						$ 0.000041666	$ 0.000041666
Common stock, shares issued						305,252,194	256,135,715
Common stock, shares outstanding						305,252,194	256,135,715
Common stock sold in public offering		23,014,000	23,000,000
Share price (in dollars per share)		$ 9.15	$ 7.5
Net proceeds from public offering		$ 197,400	$ 161,500
Common stock issued upon exercise of stock options (in shares)			3,000,000
Weighted average grant date fair value, options granted						$ 6.97	$ 4.91	$ 8.29
Intrinsic value of options exercised						$ 1,100	$ 10	$ 40
Inventories
STOCKHOLDERS' EQUITY
Stock-based compensation expense						$ 1,200	$ 0
Subsequent Event
STOCKHOLDERS' EQUITY
Proceeds from Issuance or Sale of Equity	$ 122,300
Common Stock
STOCKHOLDERS' EQUITY
Common stock issued upon exercise of stock options (in shares)						425,925	8,860	203,579
At the Market Offering Program
STOCKHOLDERS' EQUITY
Common stock sold in public offering						23,127,726	44,080,226	29,788,993
Maximum percentage of commission				3%
Proceeds from the issuance of common stock						$ 200,000	$ 301,700	$ 189,500
Weighted average price						$ 8.82	$ 6.99	$ 6.52
Second Sales Agreement
STOCKHOLDERS' EQUITY
Maximum amount of shares to be issued				$ 500,000
2023 Sales Agreement
STOCKHOLDERS' EQUITY
Maximum amount of shares to be issued														$ 450,000
Series A Convertible Preferred Stock
STOCKHOLDERS' EQUITY
Preferred stock, shares authorized						17,000	17,000
Preferred stock, par or stated value per share						$ 0.001	$ 0.001
Conversion of stock, shares issued						500
Conversion of Stock, shares converted						0	0
Preferred stock, shares outstanding						194	194
Series A Convertible Preferred Stock | Common Stock
STOCKHOLDERS' EQUITY
Common stock available in conversion, shares						97,000	97,000
Series A Convertible Preferred Stock | Private Placement
STOCKHOLDERS' EQUITY
Preferred stock, par or stated value per share						$ 1,000
Convertible price per share						$ 2
Series B Convertible Preferred Stock
STOCKHOLDERS' EQUITY
Preferred stock, shares authorized						11,500,000	11,500,000
Preferred stock, par or stated value per share						$ 0.001	$ 0.001
Convertible price per share						$ 4.75
Conversion of Stock, shares converted						1
Preferred stock, shares outstanding						2,842,158	2,842,158
Series B Convertible Preferred Stock | Issuance Of Common Stock Upon Conversion Of Preferred Stock
STOCKHOLDERS' EQUITY
Conversion of stock, shares issued						0	0
Series B Convertible Preferred Stock | Common Stock
STOCKHOLDERS' EQUITY
Common stock available in conversion, shares						2,842,158	2,842,158
Series B Convertible Preferred Stock | IPO
STOCKHOLDERS' EQUITY
Preferred stock, shares authorized						11,500,000
Convertible price per share						$ 4.75
Blank check
STOCKHOLDERS' EQUITY
Preferred stock, shares authorized						50,000,000
Stock option expense
STOCKHOLDERS' EQUITY
Total unrecognized compensation expense						$ 20,800
Unrecognized compensation cost recognition period						1 year 8 months 16 days
RSUs and PRSUs
STOCKHOLDERS' EQUITY
Total unrecognized compensation expense						$ 84,300	$ 19,900
Unrecognized compensation cost recognition period						1 year 7 months 9 days	1 year 7 months 24 days
Outstanding unvested shares						9,547,643	3,453,901
Aggregate intrinsic value of outstanding non-vested RSUs & PRSUs						$ 70,700	$ 28,100
Performance Based Restricted Stock Unit
STOCKHOLDERS' EQUITY
Outstanding unvested shares						0
The 2018 Plan
STOCKHOLDERS' EQUITY
Shares authorized					14,000,000						36,700,000				29,700,000				20,700,000				6,000,000
Number of shares available						8,917,507
2020 ESPP
STOCKHOLDERS' EQUITY
Common stock sold in public offering						497,044	435,459
Shares authorized					500,000						1,900,000				1,400,000	500,000
Unrecognized compensation cost recognition period						5 months 9 days
Percentage of purchase price					85%
Stock-based compensation expense						$ 1,500	$ 1,200	$ 1,300
Unrecognized compensation cost						700
Proceeds from Issuance or Sale of Equity						$ 3,000	$ 2,400
2021 Inducement Plan
STOCKHOLDERS' EQUITY
Shares authorized									4,750,000	2,750,000		2,750,000	2,250,000				2,250,000	1,750,000		1,750,000	1,000,000	1,000,000
Number of shares available						1,867,121

STOCKHOLDERS' EQUITY - Stock Op

STOCKHOLDERS' EQUITY - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 13, 2023	Dec. 31, 2024
Number of Options
Exercised	(3,000,000)
Stock option expense
Number of Options
Outstanding, beginning balance		18,899,849
Issued		1,731,325
Exercised		(425,925)
Expired/Cancelled		(1,987,123)
Outstanding, ending balance		18,218,126
Ending vested and expected to vest		18,218,126
Options exercisable		14,137,830
Weighted Average Exercise Price
Outstanding, beginning balance		$ 18.57
Issued		9.72
Exercised		7.67
Expired/Cancelled		23.78
Outstanding, ending balance		17.41
Ending vested and expected to vest		17.41
Options exercisable		$ 19.96
Weighted Average Remaining Contractual Life (Years)
Options outstanding, remaining term		6 years 3 months 3 days
Ending vested and expected to vest, remaining term		6 years 3 months 3 days
Options exercisable, remaining term		5 years 6 months 21 days
Aggregate Intrinsic Value
Option at ending balance		$ 2,550
Ending vested and expected to vest		2,550
Option exercisable		$ 1,527

STOCKHOLDERS' EQUITY - Restrict

STOCKHOLDERS' EQUITY - Restricted Stock Units and Performance Restricted Stock Units (Details) - RSUs and PRSUs	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Number of Shares
Outstanding, Beginning Balance | shares	3,453,901
Granted | shares	9,924,555
Vested/Released | shares	(3,150,172)
Canceled/Forfeited | shares	(680,641)
Outstanding, Ending balance | shares	9,547,643
Ending vested and expected to vest | shares	9,547,643
Weighted Average Grant Date Fair Value
Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 8.97
Weighted Average Grant Date Fair Value, Granted | $ / shares	16.53
Weighted Average Grant Date Fair Value, Vested/Released | $ / shares	12.95
Weighted Average Grant Date Fair Value, Canceled/forfeited | $ / shares	15.09
Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	15.08
Weighted Average Grant Date Fair Value, Ending vested and expected to vest | $ / shares	$ 15.08

STOCKHOLDERS' EQUITY - Stock ba

STOCKHOLDERS' EQUITY - Stock based expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Total stock-based compensation expense	$ 109,623	$ 62,625	$ 84,022
Cost of Sales
Total stock-based compensation expense	8,554
Research and development
Total stock-based compensation expense	49,270	34,926	50,242
General and administrative
Total stock-based compensation expense	$ 51,799	$ 27,699	$ 33,780

STOCKHOLDERS' EQUITY - Stock-ba

STOCKHOLDERS' EQUITY - Stock-based compensation by instrument (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Total stock-based compensation expense	$ 109,623	$ 62,625	$ 84,022
Stock option expense
Total stock-based compensation expense	21,112	45,340	58,308
Restricted stock expense
Total stock-based compensation expense	87,025	16,062	24,436
ESPP expense
Total stock-based compensation expense	$ 1,486	$ 1,223	$ 1,278

STOCKHOLDERS' EQUITY - Assumpti

STOCKHOLDERS' EQUITY - Assumptions (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Employee Stock Option
Expected dividend yield	0%	0%	0%
Employee Stock Option | Minimum
Expected term (years)	5 years 4 months 28 days	5 years 2 months 4 days	4 years 11 months 8 days
Expected volatility	85.03%	83.63%	73.73%
Risk-free interest rate	3.61%	3.59%	1.25%
Employee Stock Option | Maximum
Expected term (years)	5 years 6 months 21 days	5 years 4 months 13 days	5 years 1 month 13 days
Expected volatility	85.85%	84.21%	83.90%
Risk-free interest rate	4.33%	4.60%	4.05%
2020 ESPP
Expected term (years)	6 months	6 months	6 months
Expected dividend yield	0%	0%	0%
2020 ESPP | Minimum
Expected volatility	73.85%	72.96%	73.02%
Risk-free interest rate	4.35%	5.38%	1.98%
2020 ESPP | Maximum
Expected volatility	98.85%	83.36%	137.42%
Risk-free interest rate	5.40%	5.40%	4.78%

SEGMENT INFORMATION (Details)

SEGMENT INFORMATION (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 164,070	$ 1,189
Total cost of sales	123,995	10,755
Expenses
Research and development	282,336	344,077	$ 294,781
General and administrative	153,017	106,916	104,097
Net Income (Loss)	(372,177)	(444,037)	$ (395,893)
Increase (Decrease) in the amount of net loss
Net loss	$ (71,860)
Increase (decrease) in the percentage of net loss
Net loss	(16.20%)
Number of operating segment | segment	1
Other segment items	Other segment items include costs that are not considered significant expense segments nor reviewed by the CODM on a regular basis. Such amount includes stock-based compensation expenses, interest income, other income and expenses, and income tax benefits
Single reportable segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net sales	$ 164,070	1,189
Direct cost of goods sold	83,637	663
Acquisition related cost of sales	26,161	10,092
Royalties	14,197
Total cost of sales	123,995	10,755
Expenses
Research and development	200,361	278,032
General and administrative	97,153	88,960
Sales and marketing	26,986	21,376
Other segment items	87,752	46,104
Total expenses	412,252	$ 434,471
Increase (Decrease) in the amount of net loss
Net sales	162,881
Total cost of sales	113,240
Research and development	(77,671)
General and administrative	8,193
Sales and marketing	5,610
Other segment items	41,648
Total expenses	$ (22,220)
Increase (decrease) in the percentage of net loss
Net sales	13,698%
Total cost of sales	1,053%
Research and development	(27.90%)
General and administrative	9.20%
Sales and marketing	26.20%
Other segment items	90.30%
Total expenses	(5.10%)

EMPLOYEE BENEFIT PLAN (Details)

EMPLOYEE BENEFIT PLAN (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
EMPLOYEE BENEFIT PLAN
Defined contribution plan	$ 4.7	$ 4.1	$ 3

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
INCOME TAXES
Income tax benefit	$ 2,828	$ 3,479	$ 0
Effective tax rates	0.75%	0.78%
Loss before provision of income taxes of U.S. losses	$ 359,900	$ 433,500	395,800
Loss before provision of income taxes of foreign losses	$ 15,100	$ 14,000	$ 100
Federal statutory tax rate	21%	21%	21%

INCOME TAXES - Net deferred tax

INCOME TAXES - Net deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred income tax asset:
Net operating loss carry forwards	$ 302,875	$ 255,639
Stock-based compensation	40,909	28,609
Tax credit carryforwards	66,874	58,565
Lease liabilities	14,759	16,024
Capitalized R&D	137,577	99,107
Reserves and accruals	11,523	6,540
Deferred tax assets before valuation allowance	574,517	464,484
Less: valuation allowance	(557,587)	(446,853)
Net deferred income tax assets	16,930	17,631
Deferred tax liabilities:
Right-of-use assets	(14,228)	(13,381)
Depreciation and amortization	(35,017)	(21,597)
Net deferred tax assets (liabilities)	$ (32,315)	$ (17,347)

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of the effective income tax rate (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
INCOME TAXES
Federal statutory tax rate	21%	21%	21%
Orphan drug and research credits	2%	2%	1%
Permanent and other differences	(2.00%)	(1.00%)	(1.00%)
Stock-based compensation	(1.00%)	(1.00%)	(1.00%)
State tax, net of federal benefit	10%	1%	1%
Effective Income Tax Rate Reconciliation Expected Rate Total	30%	22%	21%
Valuation allowance	(29.00%)	(21.00%)	(21.00%)
Effective tax rate	0.75%	0.78%

INCOME TAXES - Other informatio

INCOME TAXES - Other information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Contingency [Line Items]
Net operating loss carryforwards (NOLs)	$ 15,200,000
Operating loss carryovers definite to be expired	142,400,000
Operating loss carryovers indefinite	1,200,000,000
Change in valuation allowance	110,700,000	$ 96,400,000	$ 82,900,000
Interest or penalties on unpaid tax	0	$ 0	$ 0
Federal income tax
Income Tax Contingency [Line Items]
Net operating loss carryforwards (NOLs)	1,300,000,000
Tax credit carryforwards	80,600,000
State income tax
Income Tax Contingency [Line Items]
Net operating loss carryforwards (NOLs)	331,900,000
Tax credit carryforwards	$ 19,000,000

INCOME TAXES - Unrecognized ben

INCOME TAXES - Unrecognized benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
INCOME TAXES
Unrecognized benefit - beginning of period	$ 26,107	$ 21,645	$ 18,171
Gross decreases - prior period tax positions	0	0	0
Gross increase current period tax positions	3,747	4,462	3,474
Unrecognized benefit - end of period	$ 29,854	$ 26,107	$ 21,645

LICENSES AND AGREEMENTS (Detail

LICENSES AND AGREEMENTS (Details) $ in Thousands		1 Months Ended					9 Months Ended	12 Months Ended
	May 18, 2023 USD ($) item	Jul. 31, 2024 USD ($)	Oct. 31, 2022 item	Apr. 30, 2017 USD ($)	Nov. 30, 2016 item	Aug. 31, 2011	Dec. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)
Research and development								$ 282,336	$ 344,077	$ 294,781
Through the end of 2024
Quarterly payment for research and development		$ 500
Commencing in 2025 and end of agreement term
Quarterly payment for research and development		$ 900
Strategic Alliance Agreement
Research and development								400	0	200
Research and development arrangement, contract to perform for others, costs incurred, gross							$ 5,300
Maximum | Strategic Alliance Agreement
Research and development arrangement, contract to perform for others, costs incurred, gross				$ 14,200
Sponsored research agreement
Research and development								200	200	600
First WuXi Manufacturing and Services Agreement
Number Of Suites Under The Agreement | item					2
Second WuXi Manufacturing and Services Agreement
Agreement term			3 years
Number Of Suites Under The Agreement | item			2
Patent license agreement related to the development and manufacture of TIL therapies
Research and development									0	0
License agreement								700
Phase 2 Clinical Study in Melanoma
Amount of collaborative arrangement required to be remitted									$ 600
Period of collaborative arrangement required to be remitted									60 days
Patent License Agreement, Related to approval of Amtagvi
Amount of collaborative arrangement required to be remitted							1,500	$ 1,500
Period of collaborative arrangement required to be remitted								60 days
Patent License Agreement, Related to approval of the first commercial sale of Amtagvi
Amount of collaborative arrangement required to be remitted							$ 6,000	$ 6,000
Period of collaborative arrangement required to be remitted								60 days
Cooperative Research and Development Agreement
Agreement term		5 years				5 years
Research and development								$ 2,000	$ 2,000	2,000
Notification period to terminate agreement		60 days
WuXi Apptech, Inc - Manufacturing and Services Agreement
Research and development								25,000	17,300	14,200
Cellectis S.A
Research and development								400	400	400
Novartis Pharma AG and Related Entities - License Agreement
Research and development								0	0	$ 0	$ 10,000
Number of historical asset purchase agreement. | item	2
Number of historical master cell bank license and working cell bank transfer agreement | item	1
Number of historical license agreement | item	1
Amount of milestone payment made during the period under the license agreement								$ 0	$ 0
Percent of milestone payments reimbursable	25%
Novartis Pharma AG and Related Entities - License Agreement | Non-US
Amount of milestone payments payable under the license agreement	$ 15,000
Novartis Pharma AG and Related Entities - License Agreement | Maximum | UNITED STATES
Amount of milestone payments payable under the license agreement	$ 30,000

LICENSES AND AGREEMENTS - Estim

LICENSES AND AGREEMENTS - Estimated purchase obligations (Details) - Manufacturing and Supply Agreement With Boehringer Ingelheim Biopharmaceuticals GmbH - USD ($) $ in Millions	May 18, 2023	Dec. 31, 2024
Renewal term of agreement	2 years
Years ending December 31, 2025		$ 13.6
Years ending December 31, 2026		7.2
Years ending December 31, 2027		$ 6.4

LEASES - Additional information

LEASES - Additional information (Details) $ in Thousands		12 Months Ended
	Nov. 15, 2024 USD ($) ft² item	Dec. 31, 2024 USD ($) ft²	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 USD ($)
Option to extend		true
Operating lease right-of-use assets		$ 55,201			$ 62,515
Operating lease liability		57,261			$ 74,862
Gain on termination of lease		5,568
Tenant improvement allowance		$ 8,200
Minimum
Term of contract in years		1 year
Maximum
Term of contract in years		16 years
Office Space | Minimum
Term of contract in years		12 months
Office Space | Philadelphia, Pennsylvania
Area of land | ft²		136,000
Furniture and equipment | Maximum
Term of contract in years		12 months
New Headquarters Lease | Office Space | San Carlos, California
Area of land surrendered | ft²	49,918
Early termination payment	$ 600
Brokerage fees paid	2,500
Derecognition of operating lease right-of-use assets	13,700
Derecognition of operating lease liabilities	22,300
Gain on termination of lease	8,600
Impairment due to early termination	$ 7,400	$ 7,400
Tenant improvement allowance reimbursed			$ 6,400	$ 1,600
Sub Lease Agreement | Office Space | San Carlos, California
Area of land | ft²	16,731
Term of contract in years	24 months
Number of options to extend the lease | item	2
Existence of option to extend lease	true
Renewal term in years	12 months
Percentage of increase in monthly base rent upon extension	3%
Monthly base rent	$ 100
Operating lease right-of-use assets	2,300
Operating lease liability	$ 2,300

LEASES - Right-of-use asset and

LEASES - Right-of-use asset and lease liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
LEASES
Operating lease right-of-use assets	$ 55,201	$ 62,515
Operating lease liabilities
Current portion included in current liabilities	12,896	7,777
Long-term portion included in non-current liabilities	44,365	67,085
Total operating lease liabilities	$ 57,261	$ 74,862

LEASES - Components of lease ex

LEASES - Components of lease expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
LEASES
Operating lease cost	$ 16,484	$ 17,786
Variable lease cost	3,995	7,629
Short-term lease cost	431	335
Total lease cost	20,910	25,750
Cash paid for amounts included in the measurement of lease liabilities included in cash flows from operations	18,120	16,871
Right-of-use assets obtained from entering new leases	2,306	177
Increase in right-of-use assets from lease modifications	$ 818	$ 1,033
Weighted-average remaining lease terms (years)	12 years 9 months 29 days	13 years 1 month 2 days
Weighted-average discount rates	7.90%	7.40%

LEASES - Maturities of the Comp

LEASES - Maturities of the Company's operating lease liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
2025	$ 16,949
2026	5,452
2027	4,307
2028	4,393
2028	4,481
Thereafter	57,496
Total lease payments	93,078
Less: Present value adjustment	(35,817)
Operating lease liabilities	57,261	$ 74,862
Facility leases
2025	6,039
2026	5,452
2027	4,307
2028	4,393
2028	4,481
Thereafter	57,496
Total lease payments	82,168
Less: Present value adjustment	(35,179)
Operating lease liabilities	46,989
CMO embedded leases
2025	10,910
Total lease payments	10,910
Less: Present value adjustment	(638)
Operating lease liabilities	$ 10,272

LEGAL PROCEEDINGS (Details)

LEGAL PROCEEDINGS (Details)				1 Months Ended
	Sep. 11, 2024 shares	May 12, 2020 USD ($)	Apr. 08, 2016 USD ($) item	Nov. 30, 2012 USD ($)	Jun. 30, 2012 USD ($)
Equity claim		$ 47,420
Public offering | shares	23,014,000
Solomon Capital LLC Litigation
Proceeds from lawsuit filed				$ 200,000	$ 100,000
Face amount			$ 200,000
Debt instrument, convertible, number of equity instruments | item			1,110
Reverse split ratio			0.01
Estimate of possible loss			$ 1,500,000
Damages claimed			$ 500,000