UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

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

For the quarterly period ended ~~September 30, 2022~~March 31, 2023

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

For the transition period from to

Commission file number 0-17999

ImmunoGen, Inc.

Massachusetts		04-2726691
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

830 Winter Street, Waltham, MA 02451

(Address of principal executive ~~offices, including zip~~offices) (Zip code)

(781) 895-0600

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

	Title of Each Class		Trading Symbol		Name of Each Exchange on Which Registered
	Common Stock, $.01 par value		IMGN		Nasdaq Global Select Market

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

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

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12-b2 of the Exchange Act.

Large accelerated filer ⌧	Accelerated filer ◻
Non-accelerated filer ◻	Smaller reporting company ☐
	Emerging growth company ☐

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

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

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date.

Shares of common stock, par value $.01 per share: ~~220,750,928~~226,070,419 shares outstanding as of ~~October 31, 2022.~~April 21, 2023.

Table of Contents

IMMUNOGEN, INC.

FORM 10-Q

FOR THE QUARTER ENDED ~~SEPTEMBER 30, 2022~~MARCH 31, 2023

TABLE OF CONTENTS



Item		Page Number		Page Number
	Part I		Part I
	Financial Information		Financial Information
1.	Financial Statements (Unaudited)	2	Financial Statements (Unaudited)	2

1a.	Consolidated Balance Sheets as of September 30, 2022 and December 31, 2021	2	Consolidated Balance Sheets as of March 31, 2023 and December 31, 2022	2

1b.	Consolidated Statements of Operations and Comprehensive Loss for the three and nine months ended September 30, 2022 and 2021	3	Consolidated Statements of Operations and Comprehensive Loss for the three months ended March 31, 2023 and 2022	3

1c.	Consolidated Statements of Shareholders’ Equity for the three months ended March 31, June 30, and September 30, 2022 and the three months ended March 31, June 30, September 30, and December 31, 2021	4	Consolidated Statements of Shareholders’ Equity for the three months ended March 31, 2023 and the three months ended March 31, June 30, September 30, and December 31, 2022	4

1d.	Consolidated Statements of Cash Flows for the nine months ended September 30, 2022 and 2021	5	Consolidated Statements of Cash Flows for the three months ended March 31, 2023 and 2022	5

1e.	Notes to Consolidated Financial Statements	6	Notes to Consolidated Financial Statements	6

2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	17	Management’s Discussion and Analysis of Financial Condition and Results of Operations	18

3.	Quantitative and Qualitative Disclosures about Market Risk	24	Quantitative and Qualitative Disclosures about Market Risk	24

4.	Controls and Procedures	24	Controls and Procedures	25

	Part II		Part II
	Other Information		Other Information
1A.	Risk Factors	24	Risk Factors	25

6.	Exhibits	24	Exhibits	26

	Signatures	25	Signatures	27

Forward-looking statements

This Form 10-Q includes forward-looking statements. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, these forward-looking statements relate to analyses and other information that are based on beliefs, expectations, assumptions, and forecasts of future results and estimates of amounts that are not yet determinable. These statements also relate to our prospects, future clinical, regulatory, and other developments and data releases, commercialization efforts, product candidates, and business strategies.

These forward-looking statements are identified by their use of terms and phrases, such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “predict,” “project,” “will,” and other similar terms and phrases, including references to assumptions. These statements are contained in the “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Risk Factors” sections, as well as the notes to our financial statements and other sections of this report.

We may not actually achieve the plans, intentions, or expectations disclosed in our forward-looking statements, and investors should not place undue reliance on our forward-looking statements. Additionally, these forward-looking statements involve known and unknown risks, uncertainties, and other factors that may cause actual results to be materially different from those contemplated by our forward-looking statements. These known and unknown risks, uncertainties, and other factors are described in detail in the “Risk Factors” section and in other sections of this report and our Annual Report on Form 10-K for the year ended December 31, ~~2021~~2022 filed with the Securities and Exchange Commission (SEC) on ~~February 28, 2022,~~ ~~as supplemented by our Quarterly Reports on Form 10-Q for the quarters ended~~ March ~~31, 2022 and June 30, 2022, and~~1, 2023, as updated and/or supplemented in subsequent filings with the SEC. The forward-looking statements contained herein represent our views as of the date of this Form 10-Q. Except as required by law, we disclaim any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise.

Table of Contents

ITEM 1. Financial Statements

IMMUNOGEN, INC.

CONSOLIDATED BALANCE SHEETS

(UNAUDITED)

In thousands, except per share amounts

September 30,

December 31,

2022

2021
ASSETS

Cash and cash equivalents

$
309,511

$
478,750
Accounts receivable

42

4,467
Unbilled receivable

696

2,345
Contract assets

—

3,000
Non-cash royalty receivable

3,453

4,115
Prepaid and other current assets

16,714

7,322
Total current assets

330,416

499,999
Property and equipment, net of accumulated depreciation

4,474

4,663
Operating lease right-of-use assets

10,809

12,392
Other assets

13,100

8,711
Total assets

$
358,799

$
525,765
LIABILITIES AND SHAREHOLDERS’ EQUITY

Accounts payable

$
20,178

$
18,434
Accrued compensation

8,621

5,469
Other accrued liabilities

47,136

23,077
Current portion of liability related to the sale of future royalties, net of deferred financing costs of $175 and $198, respectively

8,647

6,077
Current portion of operating lease liability

3,981

3,537
Current portion of deferred revenue

15,079

44,351
Total current liabilities

103,642

100,945
Deferred revenue, net of current portion

38,732

47,717
Operating lease liability, net of current portion

12,217

15,244
Liability related to the sale of future royalties, net of current portion and deferred financing costs of $241 and $381, respectively

25,901

34,967
Other long-term liabilities

300

1,306
Total liabilities

180,792

200,179
Commitments and contingencies (Note H)

Shareholders’ equity:

Preferred stock, $.01 par value; authorized 5,000 shares; no shares issued and outstanding as of each of September 30, 2022 and December 31, 2021

—

—
Common stock, $.01 par value; authorized 600,000 shares; 220,751 and 220,361 shares issued and outstanding as of September 30, 2022 and December 31, 2021, respectively

2,208

2,204
Additional paid-in capital

1,810,863

1,794,525
Accumulated deficit

(1,635,064)

(1,471,143)
Total shareholders’ equity

178,007

325,586
Total liabilities and shareholders’ equity

$
358,799

$
525,765


	March 31,		December 31,
	2023		2022
ASSETS
Cash and cash equivalents	$	201,249	$	275,138
Accounts receivable		27,342		12,596
Unbilled receivable		1,249		1,531
Non-cash royalty receivable		2,455		3,851
Inventory		614		—
Prepaid and other current assets		10,955		11,005
Total current assets		243,864		304,121
Property and equipment, net of accumulated depreciation		4,067		4,377
Operating lease right-of-use assets		9,627		10,231
Inventory, net of current portion		16,291		16,196
Other assets		14,496		14,011
Total assets	$	288,345	$	348,936
LIABILITIES AND SHAREHOLDERS’ EQUITY
Accounts payable	$	32,260	$	45,353
Accrued compensation		11,780		11,111
Other accrued liabilities		30,918		38,783
Current portion of liability related to the sale of future royalties, net of deferred financing costs of $150 and $162, respectively		9,014		8,659
Current portion of operating lease liability		4,213		4,096
Current portion of deferred revenue		13,444		13,856
Total current liabilities		101,629		121,858
Deferred revenue, net of current portion		34,055		36,355
Operating lease liability, net of current portion		10,049		11,148
Liability related to the sale of future royalties, net of current portion and deferred financing costs of $172 and $205, respectively		20,394		23,449
Other long-term liabilities		300		300
Total liabilities		166,427		193,110
Commitments and contingencies (Note J)
Shareholders’ equity:
Preferred stock, $.01 par value; authorized 5,000 shares; no shares issued and outstanding as of March 31, 2023 and December 31, 2022, respectively		—		—
Common stock, $.01 par value; authorized 600,000 shares; 226,070 and 226,046 shares issued and outstanding as of March 31, 2023 and December 31, 2022, respectively		2,261		2,260
Additional paid-in capital		1,854,743		1,847,638
Accumulated deficit		(1,735,086)		(1,694,072)
Total shareholders’ equity		121,918		155,826
Total liabilities and shareholders’ equity	$	288,345	$	348,936

The accompanying notes are an integral part of the consolidated financial statements.

Table of Contents

IMMUNOGEN, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

(UNAUDITED)

In thousands, except per share amounts



	Three Months Ended				Nine Months Ended				Three Months Ended
	September 30,				September 30,				March 31,
	2022		2021		2022		2021		2023		2022
Revenues:
Product revenue, net									$	29,544	$	—
License and milestone fees	$	7,382	$	2,677	$	45,247	$	3,086		15,031		30,892
Non-cash royalty revenue related to the sale of future royalties		7,993		6,533		21,537		38,768		4,839		6,428
Research and development support		—		—		831		10		455		758
Total revenues		15,375		9,210		67,615		41,864		49,869		38,078
Operating expenses:
Cost and operating expenses:
Cost of sales										626		—
Research and development		59,181		33,147		154,885		102,149		51,620		44,282
Selling, general and administrative		33,623		10,297		74,064		30,234		40,016		16,648
Total operating expenses		92,804		43,444		228,949		132,383
Total cost and operating expenses										92,262		60,930
Loss from operations		(77,429)		(34,234)		(161,334)		(90,519)		(42,393)		(22,852)
Investment income, net		1,539		11		2,183		35		2,169		54
Non-cash interest expense on liability related to the sale of future royalties and convertible senior notes		(867)		(2,751)		(3,194)		(10,952)
Interest expense on convertible senior notes		—		—		—		(47)
Other (expense) income, net		(998)		(365)		(1,576)		(648)
Non-cash interest expense on liability related to the sale of future royalties										(853)		(1,249)
Other income (expense), net										63		(98)
Net loss	$	(77,755)	$	(37,339)	$	(163,921)	$	(102,131)	$	(41,014)	$	(24,145)
Basic and diluted net loss per common share	$	(0.31)	$	(0.18)	$	(0.65)	$	(0.51)	$	(0.16)	$	(0.10)
Basic and diluted weighted-average common shares outstanding		253,511		204,844		253,371		201,212		258,848		253,263
Total comprehensive loss	$	(77,755)	$	(37,339)	$	(163,921)	$	(102,131)	$	(41,014)	$	(24,145)

The accompanying notes are an integral part of the consolidated financial statements.

Table of Contents

IMMUNOGEN, INC.

CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ EQUITY

(UNAUDITED)

In thousands


				Additional				Total					Additional				Total
	Common Stock			Paid-In		Accumulated		Shareholders’		Common Stock			Paid-In		Accumulated		Shareholders’
	Shares	Amount		Capital		Deficit		Equity		Shares	Amount		Capital		Deficit		Equity
Balance at December 31, 2020	194,998	$	1,950	$	1,419,460	$	(1,331,840)	$	89,570
Balance at December 31, 2021										220,361	$	2,204	$	1,794,525	$	(1,471,143)	$	325,586
Net loss							(34,051)		(34,051)	—		—		—		(24,145)		(24,145)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	397		4		1,282		—		1,286	173		1		619		—		620
Issuance of common stock, net of issuance costs	4,544		45		33,447		—		33,492	—		—		—		—		—
Restricted stock units vested	2		—		—		—		—
Stock option and restricted stock compensation expense	—		—		3,674		—		3,674
Directors’ deferred share unit compensation	—		—		149		—		149
Balance at March 31, 2021	199,941	$	1,999	$	1,458,012	$	(1,365,891)	$	94,120
Net loss	—		—		—		(30,741)		(30,741)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	75		1		377		—		378
Conversion of convertible senior notes	239		3		997		—		1,000
Common stock issuance costs	—		—		(34)				(34)
Stock option and restricted stock compensation expense	—		—		3,598		—		3,598
Directors’ deferred share unit compensation	—		—		144		—		144
Balance at June 30, 2021	200,255	$	2,003	$	1,463,094	$	(1,396,632)	$	68,465
Net loss	—		—		—		(37,339)		(37,339)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	95		1		367		—		368
Issuance of common stock, net of issuance costs	2,150		21		12,336		—		12,357
Issuance of pre-funded warrant, net of issuance costs	—		—		29,765		—		29,765
Restricted stock award forfeitures	(57)		(1)		1		—		—
Stock option and restricted stock compensation expense	—		—		3,298		—		3,298
Directors’ deferred share unit compensation	—		—		179		—		179
Balance at September 30, 2021	202,443	$	2,024	$	1,509,040	$	(1,433,971)	$	77,093
Net loss	—		—		—		(37,172)		(37,172)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	431		4		1,733		—		1,737
Issuance of common stock, net of issuance costs	17,487		176		108,039		—		108,215
Issuance of pre-funded warrant, net of issuance costs	—		—		169,280		—		169,280
Stock option and restricted stock compensation expense	—		—		6,224		—		6,224
Directors’ deferred share unit compensation	—		—		209		—		209
Balance at December 31, 2021	220,361	$	2,204	$	1,794,525	$	(1,471,143)	$	325,586
Net loss	—		—		—		(24,145)		(24,145)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	173		1		619		—		620
Restricted stock units vested	2		—		—		—		—	2		—		—		—		—
Stock option and restricted stock compensation expense	—		—		4,196		—		4,196	—		—		4,196		—		4,196
Directors’ deferred share unit compensation	—		—		211		—		211	—		—		211		—		211
Balance at March 31, 2022	220,536	$	2,205	$	1,799,551	$	(1,495,288)	$	306,468	220,536	$	2,205	$	1,799,551	$	(1,495,288)	$	306,468
Net loss	—		—		—		(62,021)		(62,021)	—		—		—		(62,021)		(62,021)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	108		1		410		—		411	108		1		410		—		411
Stock option and restricted stock compensation expense	—		—		4,760		—		4,760	—		—		4,760		—		4,760
Directors’ deferred share unit compensation	—		—		213		—		213	—		—		213		—		213
Balance at June 30, 2022	220,644	$	2,206	$	1,804,934	$	(1,557,309)	$	249,831	220,644	$	2,206	$	1,804,934	$	(1,557,309)	$	249,831
Net loss	—		—		—		(77,755)		(77,755)	—		—		—		(77,755)		(77,755)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan	107		2		447		—		449	107		2		447		—		449
Stock option and restricted stock compensation expense	—		—		5,336		—		5,336	—		—		5,336		—		5,336
Directors’ deferred share unit compensation	—		—		146		—		146	—		—		146		—		146
Balance at September 30, 2022	220,751	$	2,208	$	1,810,863	$	(1,635,064)	$	178,007	220,751	$	2,208	$	1,810,863	$	(1,635,064)	$	178,007
Net loss										—		—		—		(59,008)		(59,008)
Issuance of common stock, net of issuance costs										5,167		51		25,596		—		25,647
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan										103		1		423		—		424
Stock option and restricted stock compensation expense										—		—		10,610		—		10,610
Restricted stock units vested										25		—		—		—		—
Directors’ deferred share unit compensation										—		—		146		—		146
Balance at December 31, 2022										226,046	$	2,260	$	1,847,638	$	(1,694,072)	$	155,826
Net loss										—		—		—		(41,014)		(41,014)
Issuance of common stock pursuant to the exercise of stock options and employee stock purchase plan										16		1		38		—		39
Stock option and restricted stock compensation expense										—		—		6,916		—		6,916
Directors’ deferred share unit and common stock compensation										8				151		—		151
Balance at March 31, 2023										226,070	$	2,261	$	1,854,743	$	(1,735,086)	$	121,918

The accompanying notes are an integral part of the consolidated financial statements.

Table of Contents

IMMUNOGEN, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(UNAUDITED)

In thousands




	Nine Months Ended				Three Months Ended
	September 30,				March 31,
	2022		2021		2023		2022

Cash flows from operating activities:
Net loss	$	(163,921)	$	(102,131)	$	(41,014)	$	(24,145)
Adjustments to reconcile net loss to net cash used for operating activities:
Non-cash royalty revenue related to sale of future royalties		(9,027)		(35,035)		(2,157)		(2,364)
Non-cash interest expense on liability related to sale of future royalties and convertible senior notes		3,194		10,952
Non-cash interest expense on liability related to sale of future royalties						853		1,249
Depreciation and amortization		1,355		1,555		448		473
Stock and deferred share unit compensation		14,862		11,042		7,067		4,407
Change in operating assets and liabilities:
Accounts receivable		4,425		(186)		(14,746)		3,277
Unbilled receivable		1,649		(4,695)		282		(1,298)
Contract asset		3,000		(2,500)
Inventory						(709)		—
Prepaid and other current assets		(9,392)		(6,429)		50		(1,485)
Operating lease right-of-use assets		1,583		1,327		604		504
Other assets		(4,389)		2,451		(485)		39
Accounts payable		1,689		1,354		(12,975)		(2,308)
Accrued compensation		3,152		98		670		(2,061)
Other accrued liabilities		23,057		5,153		(7,913)		5,023
Deferred revenue		(38,257)		(4,104)		(2,712)		(21,957)
Operating lease liability		(2,583)		(2,394)		(982)		(756)
Net cash used for operating activities		(169,603)		(123,542)		(73,719)		(41,402)
Cash flows from investing activities:
Purchases of property and equipment		(1,116)		(1,065)		(209)		(307)
Net cash used for investing activities		(1,116)		(1,065)		(209)		(307)
Cash flows from financing activities:
Payments upon settlement of convertible senior notes		—		(1,100)
Proceeds from issuance of common stock under stock plans		1,480		2,032		39		620
Proceeds from warrant issuance, net of $181 of transaction costs		—		29,765
Proceeds from common stock issuance, net of $143 of transaction costs		—		45,815
Net cash provided by financing activities		1,480		76,512		39		620
Net change in cash and cash equivalents		(169,239)		(48,095)		(73,889)		(41,089)
Cash and cash equivalents, beginning of period		478,750		293,856		275,138		478,750
Cash and cash equivalents, end of period	$	309,511	$	245,761	$	201,249	$	437,661

The accompanying notes are an integral part of the consolidated financial statements.

Table of Contents

IMMUNOGEN, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

~~September 30, 2022~~March 31, 2023

A.	Nature of Business and Plan of Operations

ImmunoGen, Inc. (the Company) was incorporated in Massachusetts in 1981 and is focused on the development and commercialization of antibody-drug conjugates (ADCs). On November 14, 2022, the U.S. Food and Drug Administration (FDA) granted accelerated approval for ELAHERE^® (mirvetuximab soravtansine-gynx) for the treatment of ~~cancer.~~ adult patients with folate receptor alpha (FRα)-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have received one to three prior systemic treatment regimens. ELAHERE was approved under the FDA's accelerated approval program based on objective response rate (ORR), duration of response (DOR), and safety data from the pivotal SORAYA trial. Continued approval may be contingent upon verification and description of clinical benefit in a confirmatory trial.

The Company has generally incurred operating losses and negative cash flows from operations since inception, incurred a net loss of ~~$163.9~~$41.0 million during the ~~nine~~three months ended ~~September 30, 2022,~~March 31, 2023, and had an accumulated deficit of approximately ~~$1.6~~$1.7 billion as of ~~September 30, 2022. The~~March 31, 2023. To date, the Company has ~~primarily~~ funded these losses through payments received from its collaborations, ~~and~~ equity, convertible debt, and other ~~financings. To date, the Company has had no revenues from~~financings, such as royalty financing transactions, a term loan facility, and commercial sales of ~~its own products and management~~ELAHERE. Management expects to continue to ~~incur~~generate substantial operating losses for at least the near term as the Company incurs significant operating expenses related to research and development and ~~potential commercialization~~selling and marketing of ~~its portfolio.~~ELAHERE.

~~As of September 30, 2022,~~At March 31, 2023, the Company had ~~$309.5~~$201.2 million of cash and cash equivalents on hand. In April 2023, the Company executed a loan agreement with BioPharma Credit PLC, BPCR Limited Partnership, and BioPharma Credit Investments V (Master) LP, which are funds managed by Pharmakon Advisors, LP (collectively, “Pharmakon”), that provides for up to a $175.0 million senior secured term loan consisting of two tranches that each mature on April 6, 2028. The ~~Company anticipates that its~~initial tranche of $75.0 million was drawn upon execution of the loan agreement. The second tranche of $50.0 million will be available at the Company’s option upon the achievement of positive top-line data from the Company’s confirmatory MIRASOL trial and a net sales threshold for ELAHERE. This tranche may be increased to $100.0 million upon mutual agreement of the parties. In consideration of the cash received pursuant to the term loan facility, the Company’s current capital resources, and anticipated sales of ELAHERE based on sales to date, the Company has concluded that the factors which previously raised substantial doubt about its ability to continue as a going concern no longer exist as of the issuance date of these financial statements. The Company currently believes that its existing capital resources and cash from anticipated sales of ELAHERE will ~~enable it~~be sufficient to ~~meet~~fund its operational expenses and capital expenditures for more than twelve months after the date these financial statements were issued.

The Company expects to ~~raise~~generate additional funds through a combination of commercial sales of ELAHERE, equity ~~debt,~~ or other financings, ~~or generate revenues from product sales of~~such as royalty financing transactions, additional debt pursuant to the ~~Company’s lead product candidate, mirvetuximab soravtansine (MIRV), if approved, as well as~~current term loan facility, and revenues from collaborations, ~~through a combination of~~including upfront license payments, milestone payments, royalty payments, and research funding, to support its planned operating ~~activities. There can be no assurance,~~activities; however, that the Company will be able to obtain additional equity, debt, or other financing or generate revenues from product sales of MIRV, if approved, or from collaborations on terms acceptable to the Company or at all.such activities may not succeed. The failure of the Company to ~~obtain~~generate sufficient funds on acceptable terms ~~when needed~~ could have a material adverse effect on the Company’s business, results of operations, and financial condition and require the Company to defer or limit some or all of its research, development, clinical and/or ~~clinical~~commercial projects.

The Company is subject to risks common to companies in the biotechnology industry including, but not limited to, the development by its competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, manufacturing and marketing limitations, challenges entering into new collaborations, complexities associated with managing collaboration arrangements, third-party reimbursements, and compliance with governmental regulations.

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B.	Basis of Presentation and Significant Accounting Policies

Basis of Presentation

The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany transactions and balances have been eliminated. The consolidated financial statements include all of the adjustments, consisting only of normal recurring adjustments, which management considers necessary for a fair presentation of the Company’s financial position in accordance with accounting principles generally accepted in the U.S. for interim financial information. The December 31, ~~2021~~2022 consolidated balance sheet presented for comparative purposes was derived from the Company’s audited financial statements, and certain information and footnote disclosures normally included in the Company’s annual financial statements have been condensed or omitted. The preparation of interim financial statements requires the use of management’s estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the interim financial statements and the reported amounts of revenues and expenditures during the reported periods. The results of the interim periods are not necessarily indicative of the results for the entire year. Accordingly, the interim financial statements should be read in conjunction with the audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, ~~2021~~2022 filed with the SEC on ~~February 28, 2022.~~March 1, 2023.

Significant Accounting Policies

The significant accounting policies used in preparation of these condensed consolidated financial statements for the three ~~and nine~~ months ended ~~September 30, 2022~~March 31, 2023 are consistent with those discussed in Note B to the consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, ~~2021.~~2022.

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Revenue Recognition

Transaction Price Allocated to Future Performance Obligations

Deferred revenue under Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC), Revenue from Contracts with Customers (ASC 606), represents the portion of the transaction price received under various contracts attributed to performance obligations that have not been satisfied (or have been partially satisfied) and includes the portion of the transaction price for certain arrangements attributed to unexercised contract options that are considered material rights. As of ~~September 30, 2022,~~March 31, 2023, the aggregate amount of the transaction price allocated to remaining performance obligations comprising deferred revenue was ~~$53.8~~$47.5 million. The Company expects to recognize revenue on approximately 28%, ~~66%~~70%, and 6%2% of the remaining performance obligations over the next 12 months, 13 to 60 months, and 61 to 120 months, respectively; however, the timing of recognition may vary due to such factors as the amount and timing of future sales of KADCYLA^®, the timing of exercise of contract options considered to be material rights, or termination of existing development and commercialization licenses.

Contract Balances from Contracts with Customers

The following tables present changes in the Company’s contract assets and contract liabilities during the ~~nine~~three months ended ~~September 30,~~March 31, 2023 and 2022 ~~and 2021~~ (in thousands):


	Balance at								Balance at		Balance at								Balance at
	December 31, 2021		Additions		Deductions		Impact of Netting		September 30, 2022		December 31, 2022		Additions		Deductions		Impact of Netting		March 31, 2023
Contract asset	$	3,000	$	—	$	(3,000)	$	—	$	—
Contract liabilities (deferred revenue)	$	92,068	$	5,704	$	(43,961)	$	—	$	53,811	$	50,211	$	—	$	(2,712)	$	—	$	47,499



	Balance at								Balance at		Balance at								Balance at
	December 31, 2020		Additions		Deductions		Impact of Netting		September 30, 2021		December 31, 2021		Additions		Deductions		Impact of Netting		March 31, 2022
Contract asset	$	—	$	2,500	$	—	$	—	$	2,500	$	3,000	$	—	$	—	$	—	$	3,000
Contract liabilities (deferred revenue)	$	110,109	$	25	$	(4,129)	$	—	$	106,005	$	92,068	$	3,803	$	(25,760)	$	—	$	70,111

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The Company recognized the following revenues as a result of changes in contract asset and contract liability balances in the respective periods (in thousands):


	Three Months Ended				Nine Months Ended				Three Months Ended
	September 30,				September 30,				March 31,
	2022		2021		2022		2021		2023		2022
Revenue recognized in the period from:
Amounts included in contract liabilities at the beginning of the period	$	7,337	$	3,292	$	43,961	$	4,129	$	2,712	$	25,760

The timing of revenue recognition, billings, and cash collections results in billed receivables, unbilled receivables, contract assets, and contract liabilities on the consolidated balance sheets. When consideration is received, or such consideration is unconditionally due, from a customer prior to transferring goods or services to the customer under the terms of a contract, a contract liability is recorded (under the caption deferred revenue). Contract liabilities are recognized as revenue after control of the products or services is transferred to the customer and all revenue recognition criteria have been met.

During the ~~year~~three months ended ~~December~~March 31, ~~2021,~~2023, the Company ~~recorded a contract asset~~received an upfront payment of ~~$3.0~~$15.0 million ~~for a probable development milestone~~ pursuant to ~~its~~a multi-target license and option agreement executed with ~~Viridian Therapeutics, Inc. (Viridian),~~Vertex Pharmaceuticals Incorporated (Vertex) which was ~~subsequently achieved~~recorded as license and milestone fee revenue in ~~April 2022. Pursuant~~the current period, further details of which can be found in Note C, “Collaboration and License Agreements.” The Company also recognized $2.7 million of previously deferred non-cash royalty revenue related to the sale of rights to KADCYLAroyalties, further details of which can be found in Note F, “Liability Related to Sale of Future Royalties.”

During the three months ended March 31, 2022, pursuant to the Company’s license agreement with Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd. (Huadong), upon delivery of clinical materials, ~~in the nine months ended September 30, 2022,~~ the Company recognized as license and milestone fee revenue $21.6 million of the ~~remaining~~ $28.5 million ~~of the~~remaining deferred revenue balance as of December 31, 2021 related to the $45.0 million of upfront and development milestone payments previously received. Additionally, pursuant to a license agreement executed with Eli Lilly and Company (Lilly), during the ~~nine~~three months ended ~~September 30,~~March 31, 2022, the Company received an upfront ~~payments~~payment of ~~$19.5~~$13.0 million, of which ~~$13.8~~$9.2 million was recognized as

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license and milestone fee revenue and the remainder deferred, further details of which can be found in Note C, ~~“Agreements.~~“Collaboration and License Agreements.” ~~During the nine months ended September 30, 2022, the~~The Company also recognized ~~$12.5~~$4.1 million of previously deferred non-cash royalty revenue related to the sale of rights to KADCYLA^® royalties, further details of which can be found in Note E,F, “Liability Related to Sale of Future Royalties,” and $2.9 million of license and milestone fee revenue related to numerous collaborators’ rights to technological improvements that had been previously deferred, which includes $2.8 million related to Novartis Institutes for BioMedical Research, Inc.’s (Novartis) termination of certain of the license agreements between the Company and Novartis in August 2022, further details of which can be found in Note C, “Agreements.”

During the nine months ended September 30, 2021, the Company recorded a contract asset of $2.5 million for a probable development milestone pursuant to its license agreement with Viridian, which was subsequently achieved in October 2021. During the nine months ended September 30, 2021, the Company also recorded $0.2 million as license and milestone fee revenue for delivery of certain materials to Viridian that had been previously deferred, and $0.2recognized $0.1 million of license and milestone fee revenue related to numerous collaborators’ rights to technological improvements that had been previously deferred. ~~Additionally, during the nine months ended September 30, 2021, the Company recorded $3.7 million of previously deferred non-cash royalty revenue related to the sale of rights to KADCYLAroyalties.~~

Financial Instruments and Concentration of Credit Risk

Cash and cash equivalents are primarily maintained with three financial institutions in the U.S. Deposits with banks may exceed the amount of insurance provided on such deposits. Generally, these deposits may be redeemed upon demand and, therefore, ~~bear minimal~~the Company does not believe it is exposed to significant risk. The Company’s cash equivalents consist of money market funds with underlying investments primarily being U.S. Government-issued securities and high quality, short-term commercial paper. Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash, cash equivalents, and marketable securities. The Company held no marketable securities as of ~~September 30, 2022~~March 31, 2023 and December 31, ~~2021.~~2022. The Company’s investment policy, approved by the Board of Directors, limits the amount it may invest in any one type of investment, thereby reducing credit risk concentrations.

Cash and Cash Equivalents

The Company considers all highly liquid financial instruments with maturities of three months or less when purchased to be cash equivalents. As of ~~September 30, 2022~~March 31, 2023, and December 31, ~~2021,~~2022, the Company held ~~$309.5~~$201.2 million and ~~$478.8~~$275.1 million, respectively, in cash and money market funds, which were classified as cash and cash equivalents.

Non-cash Investing and Financing Activities

The Company had $0.2 million and $0.3 million of accrued capital expenditures as of ~~September 30, 2022~~March 31, 2023 and December 31, ~~2021,~~2022, respectively, which have been treated as a non-cash investing activity and, accordingly, are not reflected in the consolidated statement of cash flows.

Fair Value of Financial Instruments

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Fair value is defined under ASC 820, Fair Value Measurements and Disclosures, as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The standard describes a hierarchy to measure fair value, which is based on three levels of inputs, of which the first two are considered observable and the last unobservable, as follows:

●

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

●

Level 2 - Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

●

Level 3 – Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

As of ~~September 30, 2022~~March 31, 2023 and December 31, ~~2021,~~2022, the Company held certain assets that are required to be measured at fair value on a recurring basis. The fair value of the Company’s cash equivalents is based on quoted prices

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from active markets (Level 1 inputs). The carrying amounts reflected in the consolidated balance sheets for accounts receivable, unbilled receivables, non-cash royalty receivable, prepaid and other current assets, accounts payable, accrued compensation, and other accrued liabilities approximate fair value due to their short-term nature.

Accounts Receivable

Accounts receivable arise from product sales and amounts due from the Company’s collaboration partners. The amount from product sales represents amounts due from specialty distributors and specialty pharmacy providers in the U.S. The Company monitors economic conditions and the financial performance and credit worthiness of its counterparties to identify facts or circumstances that may indicate that its receivables are at risk of collection. The Company provides reserves against accounts receivable for estimated losses that may result from a customer’s inability to pay based on the composition of its accounts receivable, considering past events, current economic conditions, and reasonable and supportable forecasts about the future economic conditions. The contractual life of accounts receivable is generally short-term. Amounts determined to be uncollectible are charged or written-off against the reserve. For the three months ended March 31, 2023 and 2022, the Company did not record any expected credit losses related to outstanding accounts receivable.~~Common Stock Warrants~~

Inventory

Inventories are stated at the lower of cost or estimated net realizable value with cost based on the first-in first-out method. Inventory that can be used in either the production of clinical or commercial products is expensed as research and development costs when identified for use in clinical trials. The Company classifies its inventory costs as long-term when it expects to utilize the inventory beyond its normal operating cycle based on forecasted levels of sales.

Prior to the regulatory approval of its drug candidates, the Company incurs expenses for the manufacture of drug product to support clinical development that could potentially be available to support the commercial launch of those drugs. Until the date at which regulatory approval has been received or is otherwise considered probable, the Company records all such costs as research and development expenses. Inventory used in clinical trials is also expensed as research and development expense, when selected for such use.

The Company ~~accounts for common stock warrants as either equity-classified or liability-classified instruments based on~~performs an assessment of the ~~warrant’s specific terms~~recoverability of capitalized inventories during each reporting period and ~~applicable authoritative guidance included~~writes down any excess and obsolete inventory to its net realizable value in ~~ASC 480,~~ ~~Distinguishing Liabilities from Equity~~ ~~(ASC 480) and ASC 815,~~ ~~Derivatives and Hedging~~ ~~(ASC 815). The assessment considers whether~~ the ~~warrants~~period in which the impairment is first identified. Such impairment charges, should they occur, are freestanding financial instruments pursuant to ASC 480, whether the warrants meet the definition of a liability pursuant to ASC 480, and whether the warrants meet all of the requirements for equity classification under ASC 815, including whether the warrants are indexed to the Company’s own common stock and whether the warrant holders could potentially require “net cash settlement” in a circumstance outside of the Company’s control, among other conditions for equity classification. This assessment, which requires the use of professional judgment, is conducted at the time of warrant issuance and as of each subsequent quarterly period end date while the warrants are outstanding.

~~For issued or modified warrants that meet all of the criteria for equity classification, the warrants are required to be~~ recorded as a component of ~~additional paid-in capital at the time~~cost of issuance. For issued or modified warrants that do not meet all the criteria for equity classification, the warrants are required to be recorded at their initial fair value on the date of issuance and remeasured each balance sheet date thereafter. Changessales in the ~~estimated fair value of the liability-classified warrants are recognized as a non-cash gain or loss in the accompanying~~ consolidated statements of operations and comprehensive loss. The determination of whether inventory costs will be realizable requires the use of estimates by management. If actual market conditions are less favorable than projected by management, additional write-downs of inventory may be required. There were no expenses recorded for excess inventory or other impairments during the three months ended March 31, 2023. There was no inventory held by the Company during the three months ended March 31, 2022.

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Computation of Net Loss per Common Share

Basic and diluted net loss per share is calculated based upon the weighted average number of shares of common stock outstanding during the period. Shares of the Company’s common stock underlying pre-funded warrants are included in the calculation of basic and diluted earnings per share. During periods of income, participating securities are allocated a proportional share of income determined by dividing total weighted-average participating securities by the sum of the total weighted average common shares and participating securities (the two-class method). Shares of the Company’s restricted stock participate in any dividends that may be declared by the Company and are therefore considered to be participating securities. Participating securities have the effect of diluting both basic and diluted earnings per share during periods of income. During periods of loss, no loss is allocated to participating securities since they have no contractual obligation to share in the losses of the Company. Diluted loss per share is computed after giving consideration to the dilutive effect of stock options, convertible notes, and restricted stock that are outstanding during the period, except where such non-participating securities would be anti-dilutive.

The Company’s common stock equivalents, as calculated in accordance with the treasury-stock method for options and unvested restricted stock ~~and the if-converted method for the convertible notes,~~ are shown in the following table (in thousands):


	Three Months Ended		Nine Months Ended		Three Months Ended
	September 30,		September 30,		March 31,
	2022	2021	2022	2021	2023	2022
Options outstanding to purchase common stock, shares issuable under the employee stock purchase plan, and unvested restricted stock/units at end of period	31,479	20,862	31,479	20,862	39,064	27,012
Common stock equivalents under treasury stock method for options, shares issuable under the employee stock purchase plan, and unvested restricted stock/units	2,246	2,116	1,437	2,743	1,098	1,981

The Company’s common stock equivalents have not been included in the net loss per share calculation because their effect is anti-dilutive due to the Company’s net loss position.

Stock-Based Compensation

As of ~~September 30, 2022,~~March 31, 2023, the Company was authorized to grant future awards under three employee share-based compensation plans, which are the ImmunoGen, Inc. Amended and Restated 2018 Employee, Director and

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Consultant Equity Incentive Plan (the 2018 Plan), the Employee Stock Purchase Plan (the ESPP), and the ImmunoGen Inducement Equity Incentive Plan (the Inducement Plan). At the annual meeting of shareholders on June 15, 2022, the 2018 Plan was amended to provide for the issuance of stock grants, the grant of options, and the grant of stock-based awards for up to an additional 13,000,000 shares of the Company’s common stock, as well as up to 28,742,013 shares of common stock, which represent the number of shares of common stock remaining under the 2018 Plan as of April 1, 2022, and awards previously granted under the 2018 Plan and the Company’s former stock-based plans, including the ImmunoGen, Inc. 2016 and 2006 Employee, Director and Consultant Equity Incentive Plans, that forfeit, expire, or cancel without delivery of shares of common stock or which resulted in the forfeiture of shares of common stock back to the Company subsequent to April 1, 2022. The Inducement Plan was approved by the Board of Directors in December 2019, and pursuant to subsequent amendments, provides for the issuance of non-qualified option grants for up to ~~10,500,000~~13,500,000 shares of the Company’s common stock. Options awarded under the two plans are granted with an exercise price equal to the market price of the Company’s stock at the date of grant. Options vest at various periods of up to four years and may be exercised within ten years of the date of grant under each of these plans.

The stock-based awards are accounted for under ASC 718, Compensation—Stock Compensation (ASC 718). Pursuant to ASC 718, the estimated grant date fair value of awards is charged to the statement of operations over the requisite service period, which is the vesting period. The fair value of each stock option is estimated on the date of grant using the Black-Scholes option-pricing model with the weighted-average assumptions noted in the following table. As the Company has not paid dividends since inception, nor does it expect to pay any dividends for the foreseeable future, the expected dividend yield assumption is zero. Expected volatility is based exclusively on historical volatility of the Company’s stock. The expected term of stock options granted is based exclusively on historical data and represents the period of time that stock options granted are expected to be outstanding. The expected term is calculated for and applied to one group of stock options as the Company does not expect substantially different exercise or post-vesting termination behavior among its option recipients. The risk-free rate of the stock options is based on the U.S. Treasury rate in effect at the time of grant for the expected term of the stock options.

Three Months Ended September 30,

Nine Months Ended September 30,

2022

2021

2022

2021
Dividend

None

None

None

None
Volatility

83.3%

82.7%

83.2%

85.2%
Risk-free interest rate

3.44%

0.95%

2.48%

0.68%
Expected life (years)

5.6

6.0

5.9

6.0

Using the Black-Scholes option-pricing model, the weighted-average grant date fair values of options granted during the three months ended September 30, 2022 and 2021 were $3.62 and $3.99 per share, respectively, and $3.58 and $5.34 for options granted during the nine months ended September 30, 2022 and 2021, respectively.

~~A summary of option activity under the Company’s equity plans for the nine months ended September 30, 2022 is presented below (in thousands, except weighted-average data):~~

Weighted-

Number

Average

of Stock

Exercise

Options

Price
Outstanding at December 31, 2021

21,219

$
6.28
Granted

11,290

5.05
Exercised

(280)

3.82
Forfeited/Canceled

(825)

9.46
Outstanding at September 30, 2022

31,404

$
5.78

In 2020, the Company issued 2.6 million performance-based stock options to certain employees that will vest upon the achievement of specified performance goals. Upon assessment of the performance-based stock option awards as of December 31, 2021, the Company determined the first performance goal to be probable of vesting and, as such, recorded $2.6 million of stock-based compensation expense for the year ended December 31, 2021. In May 2022, the first performance goal was achieved, resulting in the vesting of 25% of the 2.6 million performance-based stock options. The fair value of the remaining unvested performance-based stock options that could be expensed in future periods is $7.8 million.

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	Three Months Ended March 31,
	2023	2022
Dividend	None	None
Volatility	82.3%	83.0%
Risk-free interest rate	3.65%	1.81%
Expected life (years)	5.6	6.0

Using the Black-Scholes option-pricing model, the weighted-average grant date fair values of options granted during the three months ended March 31, 2023 and 2022 were $3.26 and $3.78 per share, respectively.

A summary of option activity under the Company’s equity plans for the three months ended March 31, 2023 is presented below (in thousands, except weighted-average data):


		Weighted-
	Number	Average
	of Stock	Exercise
	Options	Price
Outstanding at December 31, 2022	33,126	$	5.76
Granted	4,757		4.62
Exercised	(16)		2.31
Forfeited/Canceled	(763)		5.60
Outstanding at March 31, 2023	37,104	$	5.61

In 2020, the Company issued 2.6 million performance-based stock options to certain employees with vesting conditioned upon the achievement of specified performance goals. In 2022, 75% of the 2.6 million performance-based stock options vested upon achievement of specified performance goals and 12.5% were forfeited. There was no stock-based compensation recorded during the three months ended March 31, 2023 and 2022 related to these options. The fair value of the remaining unvested performance-based stock options that could be expensed in future periods is $1.3 million.

A summary of restricted stock unit activity under the Company’s equity plans for the ~~nine~~three months ended ~~September 30, 2022~~March 31, 2023 is presented below (in thousands, except weighted-average data):


	Number of	Weighted-		Number of	Weighted-
	Restricted	Average Grant		Restricted	Average Grant
	Stock Shares	Date Fair Value		Stock Shares	Date Fair Value
Unvested at December 31, 2021	77	$	5.59
Vested	(2)		2.53
Unvested at September 30, 2022	75	$	5.68
Unvested at December 31, 2022				138	$	5.45
Granted				1,824		4.65
Forfeited				(2)		4.66
Unvested at March 31, 2023				1,960	$	4.71

In June 2018, the Company's Board of Directors, with shareholder approval, adopted the Employee Stock Purchase Plan (ESPP). Following the automatic share increase on January 1, 2021, pursuant to the ESPP’s “evergreen” provision, an aggregate of 2,000,000 shares of common stock have been reserved for issuance under the ESPP. ESPP purchase periods are six months and begin on January 1 and July 1 of each year, with purchase dates occurring on the final business day of the given purchase period. The fair value of each ESPP award is estimated on the first day of the offering period using the Black-Scholes option-pricing model. The Company recognizes share-based compensation expense equal to the fair value of the ESPP awards on a straight-line basis over the offering period.

Stock compensation expense related to stock options and restricted stock unit awards granted under the stock plans and the ESPP was ~~$5.3~~$6.9 million and ~~$14.3~~$4.2 million during the three ~~and nine~~ months ended ~~September 30,~~March 31, 2023 and 2022, ~~respectively, compared to stock compensation expense of $3.3 million and $10.6 million for the three and nine months ended September 30, 2021,~~ respectively. As of ~~September 30, 2022,~~March 31, 2023, the estimated fair value of unvested employee awards ~~exclusive of performance awards,~~ was ~~$54.3~~$72.4 million. The weighted-average remaining vesting period for these awards is approximately three years.

Segment Information

During all periods presented, the Company continued to operate in one reportable business segment under the management approach of ASC 280, Segment Reporting, which is the business of ~~the discovery~~development and ~~development~~commercialization of ADCs for the treatment of cancer.

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During the three months ended ~~September 30, 2022, 52%, 30% and 18%~~March 31, 2023, 59% of revenues were generated from ~~Roche, Lilly,~~net U.S. sales of ELAHERE to four specialty distributors and ~~Novartis,~~specialty pharmacy providers, and 30% and 10% of revenues were generated from agreements with Vertex and Roche, respectively, compared to ~~71%~~59%, 24% and ~~28%~~17% of revenue from ~~Roche~~agreements with Huadong, Lilly, and ~~Viridian,~~Roche, respectively, during the three months ended September 30, 2021. During the nine months ended September 30, 2022, 43%, 32%, and 20% of revenues were from Huadong, Roche, and Lilly, respectively, compared to 93% of revenues from Roche in the nine months ended September 30, 2021. Revenue from Roche in all periods consisted of non-cash royalty revenue.March 31, 2022. There were no other customers of the Company that generated significant revenues in the three ~~and nine~~ months ended ~~September 30, 2022~~March 31, 2023 and ~~2021.~~2022.

Recently Adopted Accounting Pronouncements

There were no recently issued or effective FASB Accounting Standards Updates (ASUs) that had, or are expected to have, a material effect on the Company's results of operations, financial condition, or liquidity.

C.Collaboration and License Agreements

~~Significant Collaborative Agreements~~The Company has numerous collaboration and license agreements with third parties. These agreements typically provide the licensee with rights to use the Company’s ADC platform technology with the licensee’s antibodies or related targeting vehicles to a defined target to develop products. The licensee is generally responsible for the development, clinical testing, manufacturing, registration, and commercialization of any resulting product candidate. As part of these agreements, the Company is generally entitled to receive upfront fees, potential milestone payments, royalties on the sales of any resulting products, and research and development funding based on activities performed at our collaborative partner’s request. See below for details regarding the Company’s collaboration and license agreements with activity in the financial statement periods presented.

Vertex

In February 2023, the Company entered into a multi-target license and option agreement with Vertex, pursuant to which the Company granted Vertex rights to the Company’s ADC technology to research and evaluate ADCs directed to specified targets, with an option to obtain worldwide exclusive development and commercialization licenses to a specified number of targets (each, an Option and, collectively, the Options) before the end of the research term. Under the terms of the agreement, the Company received a non-refundable upfront payment of $15.0 million, reflecting the initial research targets selected by Vertex. During the research term, Vertex also has the right to select additional research targets in exchange for an additional license fee per target. In addition, upon exercise of each Option by Vertex, the Company will be eligible to receive up to approximately $337.0 million per target in potential option exercise fees and milestone payments based on the achievement of pre-specified development, regulatory, and sales-based milestones. With respect to each target that Vertex exercises an Option, the Company will also be eligible to receive tiered royalties, on a product-by-product basis, as a percentage of worldwide annual net sales by Vertex, its affiliates and sublicensees, based on certain net sales thresholds. Vertex is responsible for all costs related to the research and development of the compounds during the research term and commercialization of any ensuing products.

The Company evaluated the agreement and determined it was within the scope of ASC 606. The Company determined the promised goods and services included a license to use the Company’s intellectual property and know-how to research, manufacture, and evaluate products related to each of the initial research targets selected by Vertex during the research term. The Company determined that the agreement has a single performance obligation for these promised goods and services.

The Options to obtain exclusive development and commercialization licenses and the right to select additional research targets during the research term do not represent a material right as the fees associated with each option are at or above the standalone selling price. Accordingly, upon exercise, these Options will be accounted for as a separate arrangement.

The transaction price related to the single performance obligation was determined to consist of the upfront payment of $15.0 million.

The transfer of intellectual property and know-how to Vertex to allow Vertex to derive benefit from the license over the research term was completed during the three months ended March 31, 2023. As such, the Company’s performance obligation was satisfied, and the Company recognized $15.0 million of license and milestone fee revenue during the three months ended March 31, 2023.

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Lilly

In February 2022, the Company entered into a license agreement with Lilly, pursuant to which the Company granted Lilly worldwide exclusive rights to research, develop, and commercialize antibody-drug conjugates based on the Company’s novel camptothecin technology. Under the terms of the license agreement, the Company received a non-refundable upfront payment of $13.0 million, reflecting initial targets selected by Lilly. ~~In August~~During 2022, pursuant to the terms of the agreement, Lilly selected an additional ~~target~~targets for which the Company received ~~a $6.5~~an additional $13.0 million ~~payment.~~in non-refundable payments. Lilly may select a pre-specified number of additional targets, with the Company eligible to receive an additional ~~$26.0~~$19.5 million in exercise fees if Lilly licenses the full number of remaining additional targets over a specified period following the effective date of the license agreement, with the potential for up to $1.7 billion in development and sales-based milestone payments if all targets are selected and all milestones are realized. In addition, the Company is entitled to receive tiered

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royalties, on a product-by-product basis, as a percentage of worldwide annual net sales by Lilly, based on certain net sales thresholds. Lilly is responsible for all costs associated with the research, development, and commercialization of any ensuing products.

The Company evaluated the agreement and determined it was within the scope of ASC 606. The Company determined the promised goods and services included an exclusive license to use the Company’s intellectual property and know-how to research, develop, and commercialize products related to each of the initial targets selected by Lilly. Each of these licenses is distinct, as Lilly can derive benefit from each license independent of any other initial target licenses. Accordingly, the license to each of the initial targets selected by Lilly represents a separate performance obligation. Lilly has the right to replace each of the initial licensed targets once during a specified term for no additional consideration. If Lilly fails to advance an initial or replacement target to a specified stage within a specified period from the date the target was selected, Lilly’s rights to the respective target will cease and will revert back to the Company. The Company determined Lilly’s right to a replacement target for each of the initial targets represented a material right. Each material right is therefore a separate performance obligation.

Lilly’s right to select additional targets does not represent a material right as the target fee for each additional target is the same and is also consistent with the target fee for each of the initial targets selected by Lilly. Accordingly, each additional target selected by Lilly is accounted for as a separate arrangement.

The transaction price related to the initial targets was determined to consist of the upfront payment of $13.0 million. Future development milestones have been fully constrained. Any consideration related to sales-based milestones (including royalties) will be recognized when the related sales occur as these amounts have been determined to relate predominantly to the license granted to Lilly. The transaction price of $13.0 million was allocated to the performance obligations based on their relative stand-alone selling prices. In consideration of ~~each target being at the same stage of development at the time of the initial license or at the time of replacement and each target having approximately the same earnings potential,~~ the Company allocated the $13.0 million transaction price equally across the initial target licenses and the corresponding material rights to obtain licenses to replacement targets, adjusted based on the probability that Lilly would exercise those rights. The Company considered pharmaceutical industry data of the probability of early-stage assets to advance to clinical stage in determining the probability that Lilly would exercise its option to a replacement target. Accordingly, $9.2 million and $3.8 million of the total transaction price was allocated to the initial targets and the material rights to obtain licenses to replacement targets, respectively.

The license terms and accounting outlined above are the same for the additional target license selected. Accordingly, $4.6 million and $1.9 million of the $6.5 million transaction price was allocated to the target selected and the material right to obtain a license to a replacement target, respectively.

The Company re-evaluates the transaction price for each arrangement, including its estimated variable consideration included in the transaction price and all constrained amounts, at each reporting period and as uncertain events are resolved or other changes in circumstances occur.

~~The~~ transfer of intellectual property and know-how to Lilly to allow for Lilly to derive benefit from the initial and additional target licenses was completed during the three months ended March 31, 2022. As such, during ~~the nine months ended September 30,~~ 2022 the Company recognized ~~$13.8~~$18.4 million of license and milestone fee revenue related to the portion of the transaction price allocated to the initial and additional target ~~licenses.~~licenses, of which $9.2 million was recorded during the three months ended March 31, 2022. The ~~$5.7~~$7.6 million allocated to the material rights to obtain licenses to replacement targets is included in long-term deferred revenue as of ~~September 30, 2022~~March 31, 2023 and will be recognized when the right is either exercised or expires.

~~Roche~~

In 2000, the Company granted Genentech, now a unit of Roche, an exclusive development and commercialization license to use the Company’s maytansinoid ADC technology. Pursuant to this agreement, Roche developed and received marketing approval for its HER2-targeting ADC, KADCYLA, in the U.S., Japan, the European Union, and numerous other countries. In accordance with the Company’s revenue recognition policy, $21.5 million and $38.8 million of non-cash royalties on net sales of KADCYLA were recognized and included in non-cash royalty revenue for the nine months ended September 30, 2022 and 2021, respectively. The Company sold its rights to receive royalty payments on the net sales of KADCYLA through two separate transactions in 2015 and 2019. Following the 2019 transaction, OMERS, the defined benefit pension plan for municipal employees in the Province of Ontario, Canada, is entitled to receive all of these royalties.

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Huadong

In October 2020, the Company entered into a collaboration and license agreement with Huadong. The collaboration and license agreement grants Huadong an exclusive, royalty-bearing, and sublicensable right to develop and commercialize ~~mirvetuximab soravtansine~~ELAHERE (the Licensed Product) in the People’s Republic of China, Hong Kong, Macau, and Taiwan (collectively, Greater China). The Company retains exclusive rights to the Licensed Product outside of Greater China. Under the terms of the collaboration and license agreement, the Company received a non-refundable upfront payment of $40.0 million with the potential for approximately $265.0 million in development, regulatory, and sales-based milestone payments. In ~~December 2021,~~addition, the Company is entitled to receive tired royalties ranging from low double digits to high teens as a percentage of commercial sales of the licensed product, if approved, by Huadong in Greater China, subject to adjustment in specified circumstances. To date, the Company has received ~~a $5.0~~$15.0 million ~~payment upon achievement of a development milestone.~~in milestone payments.

The Company determined that revenue related to the agreement would be recognized as the clinical supply of the Licensed Product is delivered to Huadong, estimated to be completed over approximately two years. Accordingly, based on clinical supply delivered to Huadong during the ~~nine~~three months ended ~~September 30,~~March 31, 2022, the Company recorded $21.6 million of the remaining $28.5 million of deferred revenue as of December 31, 2021 related to ~~the~~ $45.0 million of upfront and development milestone payments previously received.

~~Viridian~~Roche

In ~~October 2020, the Company entered into a license agreement with Viridian pursuant to which~~2000, the Company granted ~~Viridian~~Genentech, now a unit of Roche, an exclusive development and commercialization license to use the ~~exclusive right~~Company’s maytansinoid ADC technology. Pursuant to ~~develop~~this agreement, Roche developed and ~~commercialize an insulin-like growth factor-1 receptor (IGF-1R) antibody~~received marketing approval for ~~all non-oncology indications that do not use radiopharmaceuticals~~its HER2-targeting ADC, KADCYLA, in ~~exchange for an upfront payment,~~the U.S., Japan, the European Union, and numerous other countries. In accordance with the ~~potential to receive up to a total~~Company’s revenue recognition policy, $4.8 million and $6.4 million of ~~$143.0 million in development, regulatory, and sales-based milestone payments plus~~non-cash royalties on ~~the commercial~~net sales of ~~any resulting product. In the three months ended December 31, 2021, a $3.0 million development milestone became probable of being achieved, which was allocated to the previously delivered license~~KADCYLA were recognized and ~~recognized as~~included in non-cash royalty revenue ~~as a component of license and milestone fees~~ for the three months ended ~~December~~March 31, ~~2021. The development milestone was subsequently achieved in April 2022.~~

~~Novartis~~

2023 and 2022, respectively. The Company previously granted Novartis exclusive development and commercialization licenses to the Company’s maytansinoid and IGN ADC technology for use with antibodies to specified targets under a now-expired right-to-test agreement established in 2010. In August 2022, Novartis terminated certain of the remaining development and commercialization licenses. The Company had $2.8 million of deferred revenue associated with the terminated licenses related to the portion of the transaction price previously allocated tosold its rights to ~~future technological improvements. In consideration that no technological improvements would be provided to Novartis~~receive royalty payments on the net sales of KADCYLA through two separate transactions in 2015 and ~~therefore, no unsatisfied obligations were remaining related to such licenses,~~2019. Following the ~~$2.8 million was recorded as revenue and~~2019 transaction, OMERS, the defined benefit pension plan for municipal employees in the Province of Ontario, Canada, is included in license and milestone fees for the three and nine months ended September 30, 2022. With respect to the remaining license, $0.8 million of deferred revenue related to the portion of the transaction price previously allocated to rights to future technological improvements continues to be amortized over the remaining estimated term of the license agreement, and we are entitled to receive ~~up to a total~~all of ~~$199.5 million in potential milestone payments, of which $5 million has been received to date, plus royalties on the commercial sales of any resulting products.~~these royalties.

For additional information related to these agreements, as well as the Company’s other ~~significant collaborative~~collaboration and license agreements, please read Note C, ~~“Agreements - Significant Collaborative~~“Collaboration and License Agreements,” to the audited financial statements included within the Company’s Annual Report on Form 10-K for the year ended December 31, ~~2021~~2022 filed with the SEC on ~~February 28, 2022.~~March 1, 2023.

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D.Product Revenue Reserves and Allowances

InNovember2022,the FDAgrantedacceleratedapprovalforELAHEREforthetreatmentof adult patients with FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritonealcancer,whohavereceivedonetothreepriorsystemictreatmentregimens. The Company recorded net product revenue of $29.5 million from U.S. sales of ELAHERE during the three months ended March 31, 2023.

The following table summarizes activity in each of the product revenue reserve and allowance categories for the three months ended March 31, 2023 and 2022 (in thousands):


	Three Months Ended
	March 31,
	2023		2022
Beginning balance at January 1	$	313	$	—
Provision related to sales in the current period		4,144		—
Credits and payments made		(1,533)		—
Ending balance at March 31	$	2,924	$	—

E.Inventory

Capitalized inventory consists of the following at March 31, 2023 and December 31, 2022 (in thousands):


	March 31,		December 31,
	2023		2022
Raw materials	$	15,983	$	15,952
Work in process		639		—
Finished goods		283		244
Total Inventory	$	16,905	$	16,196

D.F.

Liability Related to Sale of Future Royalties

In 2015, Immunity Royalty Holdings, L.P. (IRH) purchased the right to receive 100% of the royalty payments on commercial sales of KADCYLA arising under the Company’s development and commercialization license with Genentech, until IRH had received aggregate royalties equal to $235.0 million or $260.0 million, depending on when the aggregate royalties received by IRH ~~reach~~reached a specified milestone. Once the applicable threshold was met, the Company would thereafter have received 85% and IRH would have received 15% of the KADCYLA royalties for the remaining royalty term. At ~~the~~ consummation of the transaction, the Company received cash proceeds of $200 million. As part of this sale, the Company incurred $5.9 million of transaction costs, which are presented net of the liability in the

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accompanying consolidated balance sheet and are being amortized to interest expense over the estimated life of the royalty purchase agreement. Although the Company sold its rights to receive royalties from the sales of KADCYLA, as a result of its ~~then~~ ongoing involvement in the cash flows related to these royalties, the Company continues to account for these royalties as revenue and recorded the $200.0 million in proceeds from this transaction as a liability related to sale of future royalties (Royalty Obligation) that is being amortized using the interest method over the estimated life of the royalty purchase agreement.

In January 2019, the Company sold its residual rights to receive royalty payments on commercial sales of KADCYLA to OMERS for a payment of $65.2 million (amount is net of $1.5 million in broker fees). Simultaneously, OMERS purchased IRH’s right to the royalties the Company previously sold to IRH as described above, therefore obtaining the rights to 100% of the royalties received from that date on. Because the Company will not be involved with the cash flows related to the residual royalties, the $65.2 million of net proceeds received from the sale of its residual rights to receive royalty payments was recorded as deferred revenue and ~~will be~~is being amortized as the royalty revenue related to the residual rights is earned using the units of revenue approach. During the second quarter of 2021, the aggregate royalty threshold was met and, in accordance with the Company’s revenue recognition policy, ~~$12.5~~$2.7 million and ~~$3.7~~$4.1 million of revenue related to the residual rights was ~~recognized~~recorded and is included in non-cash royalty revenue for the ~~nine~~three months ended ~~September 30,~~March 31, 2023 and 2022, ~~and 2021,~~ respectively. Additionally, the purchase of IRH’s interest by OMERS did not

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result in an extinguishment or modification of the original instrument and, accordingly, the Company continues to account for the remaining obligation as a liability as outlined above.

The following table shows the activity within the liability account during the ~~nine-month~~three-month period ended ~~September 30, 2022~~March 31, 2023 (in thousands):



	Nine Months Ended		Three Months Ended
	September 30, 2022		March 31, 2023
Liability related to sale of future royalties, net — beginning balance	$	41,044	$	32,108
Proceeds from sale of future royalties, net		—		—
KADCYLA royalty payments received and paid		(9,690)		(3,553)
Non-cash interest expense recognized		3,194		853
Liability related to sale of future royalties, net — ending balance	$	34,548	$	29,408

The Company receives royalty reports and royalty payments related to sales of KADCYLA from Roche one quarter in arrears. As royalties are remitted to OMERS, the balance of the Royalty Obligation will be effectively repaid over the life of the agreement. In order to determine the amortization of the Royalty Obligation, the Company is required to estimate the total amount of future royalty payments to be received and remitted as noted above over the life of the agreement. The sum of these amounts less the $200 million proceeds the Company received from IRH will be recorded as interest expense over the life of the Royalty Obligation. ~~Since inception, the~~The Company’s estimate of this total interest expense has resulted in an imputed annual interest rate of 10.5%, since inception, and a current imputed interest rate of ~~8.7%~~10.0% as of ~~September 30, 2022.~~March 31, 2023. The Company periodically assesses the estimated royalty payments to IRH/OMERS, and to the extent such payments are greater or less than its initial estimates, or the timing of such payments is materially different than its original estimates, the Company will prospectively adjust the amortization of the Royalty Obligation. There are a number of factors that could materially affect the amount and timing of royalty payments from ~~Genentech,~~Roche, most of which are not within the Company’s control. Such factors include, but are not limited to, changing standards of care, the introduction of competing products, manufacturing or other delays, biosimilar competition, patent protection, adverse events that result in governmental health authority imposed restrictions on the use of the drug products, significant changes in foreign exchange rates as the royalties are paid in U.S. dollars (USD) while significant portions of the underlying sales of KADCYLA are made in currencies other than USD, and other events or circumstances that could result in reduced royalty payments from KADCYLA, all of which would result in a reduction of non-cash royalty revenues and ~~the~~ non-cash interest expense over the life of the Royalty Obligation. Conversely, if sales of KADCYLA are more than expected, the non-cash royalty revenues and the non-cash interest expense recorded by the Company would be greater over the term of the Royalty Obligation.

E.G.

Income Taxes

The liability method is used in the Company’s accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse.

As part of the Tax Cuts and Jobs Act of 2017 (TCJA), beginning with the 2022 tax year, the Company is required to capitalize research and development expenses, as defined under Internal Revenue Code section 174. For expenses that are incurred for research and development in the U.S., the amounts will be amortized over five years, and expenses that

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are incurred for research and experimentation outside the U.S. will be amortized over 15 years. ~~The Company expects that this provision will result in a significant decrease to its 2022 tax loss, but will not result in an actual tax liability for 2022.~~

~~During the nine months ended September 30, 2022,~~As of March 31, 2023, the Company ~~transferred certain of its intellectual property rights to~~determined a ~~newly formed Swiss subsidiary. This transfer resulted in a significant~~provision for income ~~inclusion~~tax was not required for ~~U.S. tax purposes which has been completely offset by utilization of a portion of~~ the ~~Company’s net operating loss carryforwards that existed before the transaction, resulting in no income tax.~~ calendar year ended December 31, 2023.

F.H.

Capital Stock

Pre-Funded Warrants

~~On August 11, 2021, the Company entered into a Securities Purchase Agreement (SPA) with RA Capital Healthcare Fund, L.P. (RA Capital), pursuant~~Pursuant to which the Company agreed to sell to RA Capital a pre-funded warrant to purchase up to an aggregate of 5,434,782 shares of the Company’s common stock for $5.51 per share of common stock underlying the pre-funded warrant. The per share exercise price of the pre-funded warrant is $0.01. The private placement resultedtransactions completed in ~~aggregate net proceeds of $29.7 million.~~

~~In connection with a public offering in December~~ 2021, the Company issued pre-funded warrants to purchase up to an aggregate of ~~16,000,000~~21,434,782 and 11,363,636 shares of the Company’s common stock to RA Capital and Redmile Group, LLC, ~~respectively, for $6.59 per share of common stock underlying the pre-funded warrants, which, together with the~~respectively. The per share exercise price of ~~$0.01,~~the pre-funded warrants is ~~equal to $6.60, the public offering price of the shares of common stock in the public offering, which resulted in aggregate net proceeds of $169.3 million.~~$0.01. RA Capital and Redmile Group, LLC are each considered related parties pursuant to ASC 850, Related Party Disclosures.

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The pre-funded warrants’ fundamental transaction provision does not provide the warrant holders with the option to settle any unexercised warrants for cash in the event of any fundamental transactions; rather, in all fundamental transaction scenarios, the warrant holder will only be entitled to receive from the Company or any successor entity the same type or form of consideration (and in the same proportion) that is being offered and paid to the shareholders of the Company in connection with the fundamental transaction, whether that consideration be in the form of cash, stock or any combination thereof. The pre-funded warrants also include a separate provision whereby the exercisability of the warrants may be limited if, upon exercise, the warrant holder or any of its affiliates would beneficially own more than 9.99% of the Company’s common stock. This threshold is subject to the holder’s rights under the pre-funded warrants to increase or decrease such percentage to any other percentage not in excess of 19.99% upon at least 61 days’ prior notice from the holder to the Company.

The Company assessed the pre-funded warrants for appropriate equity or liability classification pursuant to the Company’s accounting policy described in Note B, “Summary of Significant Accounting Policies.” During this assessment, the Company determined the pre-funded warrants are freestanding instruments that do not meet the definition of a liability pursuant to ASC 480 and do not meet the definition of a derivative pursuant to ASC 815. The pre-funded warrants are indexed to the Company’s common stock and meet all other conditions for equity classification under ASC 480 and ASC 815. Based on the results of this assessment, the Company concluded that the pre-funded warrants are freestanding equity-linked financial instruments that meet the criteria for equity classification under ASC 480 and ASC 815. Accordingly, the pre-funded warrants were classified as equity and accounted for as a component of additional paid-in capital at the time of issuance and at each subsequent balance sheet date. The Company also determined that the pre-funded warrants should be included in the determination of basic and diluted earnings per share in accordance with ASC 260, Earnings per Share.

Compensation Policy for Non-Employee Directors

Pursuant to the Compensation Policy for Non-Employee Directors, as amended, non-employee directors are granted ~~deferred share~~restricted stock units (RSUs) upon initial election to the Board of Directors and annually thereafter. Initial ~~awards~~ and annual ~~retainers~~RSUs vest ~~quarterly~~annually over approximately three years and one year from the date of grant, respectively, contingent upon the individual remaining a director of ImmunoGen as of each vesting date. The number of ~~deferred share units~~RSUs awarded is fixed per the policy on the date of the award. All unvested ~~deferred share units~~RSUs will automatically vest immediately prior to the occurrence of a change of ~~control. The redemption amount of deferred share units issued will be paid~~control or in ~~shares of common stock of~~ the ~~Company on the date~~event a director ceases to beserve as a member of the Board ~~of Directors.~~due to death or disability. Directors can elect to defer or re-defer RSU awards under the Company’s 2004 Non-Employee Director Compensation and Deferred Share Unit Plan, as amended.

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Pursuant to the Compensation Policy for Non-Employee Directors, as amended, non-employee directors also receive stock option awards upon initial election to the Board of Directors and annually thereafter. The directors received a total of approximately ~~322,000~~321,622 and 352,000 options in 2022 and 2021, respectively, and the related compensation expense for the three ~~and nine~~ months ended ~~September 30,~~March 31, 2023 and 2022 ~~and 2021~~ is included in the amounts discussed in the “Stock-Based Compensation” section of Note B above.

G.I.

Leases

The Company currently has one real estate lease for the rental of approximately 120,000 square feet of laboratory and office space at 830 Winter Street, Waltham, Massachusetts through March 2026. In 2020, the Company executed four subleases for approximately 65,000 square feet of this space in the aggregate through the remaining initial term of the lease. During 2022, in order to reclaim laboratory and office space, the ~~nine~~Company modified two of its sublease agreements to terminate the subleases early in January 2023. As a result of the sublease terminations, during the three months ended ~~September 30, 2022 and 2021,~~March 31, 2023 the Company recorded sublease income, ~~of $2.4 million and $3.7 million, respectively,~~ inclusive of the sublessees’ proportionate share of operating expenses and real estate taxes for the ~~period. The decrease in~~period, of $0.8 million compared to $1.2 million during the ~~current year period is driven by amortization of the lease incentive discussed further below.~~

~~In June 2022, in order to reclaim laboratory and office space, the Company modified one of its sublease agreements to terminate the sublease early, targeting an end date of~~three months ended March 31, ~~2023. Pursuant to the amended sublease agreement, the Company is required to pay the sublessee $3.5 million as a lease incentive,~~2022.

Table of ~~which $1.8 million was paid in June 2022 and the remainder will be paid at the end of the sublease term. No other terms from the original sublease agreement were modified. In accordance with ASC 842,~~ ~~Leases~~, the $3.5 million lease incentive is being recognized on a straight-line basis over the remaining sublease term. As a result of the early termination, the Company will forego $2.1 million in minimum future rental payments. The Company assessed the underlying right-of-use asset and determined there was no impairment.Contents

~~Except as disclosed above, there~~There have been no ~~other~~ material changes in lease obligations from those disclosed in Note J,K, “Leases,” to the consolidated financial statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, ~~2021.~~2022 filed with the SEC on March 1, 2023.

H.J. Commitments and Contingencies

~~Research Collaboration Agreement~~

In June 2022, the Company entered into a research collaboration agreement with Oxford BioTherapeutics Ltd (OBT) to develop novel ADCs utilizing the Company’s linker-payload technology directed to targets identified via OBT's proprietary OGAP^® discovery platform. Under the terms of the agreement, OBT received a non-refundable $7.5 million upfront payment reflecting OBT's preclinical programs to be included in the collaboration. Additionally, over the initial three-year term of the agreement, the Company is committed to reimbursing OBT up to $2.8 million annually to support research activities dependent on the number of active programs. Otherwise, each party is responsible for its own costs associated with the joint research plan. After antibodies generated by OBT have been conjugated with the Company's proprietary linker-payload technology, each party will have the opportunity to select one or more development programs to further develop on its own. Each party will be eligible to receive milestone payments based on the achievement of pre-specified development and regulatory milestones, as well as tiered royalties as a percentage of worldwide commercial sales, with respect to each program selected by the other party. Once a party has selected a given program, it will be solely responsible for all research and development costs associated with that specific program. If at the end of the initial three-year term, either party elects not to extend the research term, predetermined opt-out fees may apply based on the number of programs selected for further development by each party. At any time starting twelve months after the effective date of the agreement, the Company may terminate the agreement in its sole discretion upon 90 days written notice to OBT. Otherwise, the agreement may be terminated by either party for a material breach by the other party, subject to notice and cure provisions.

~~In accordance with ASC 730,~~ ~~Research and Development~~, the $7.5 million upfront payment made to OBT was expensed as incurred and is included in research and development expense for the nine months ended September 30, 2022. The committed reimbursement to OBT and other research costs will be expensed as incurred over the research term, with $0.6 million recorded as research and development expenses during the three and nine months ended September 30, 2022.

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Manufacturing Commitments

As of ~~September 30, 2022,~~March 31, 2023, the Company had noncancelable obligations under several agreements related to in-process and future manufacturing of antibody, drug substance, and cytotoxic agents required for supply of the Company’s product candidates totaling ~~$14.6~~$22.3 million. Additionally, pursuant to commercial agreements for future production of antibody, our noncancelable commitments total ~~$40.6~~$46.7 million at ~~September 30, 2022.~~March 31, 2023.

Litigation

The Company is not a party to any material litigation.

I.K.Related Party Transactions

Stuart A. Arbuckle serves as the chief operating officer at Vertex and has served as a member of the Company’s board of directors since 2018. In February 2023, the Company entered into a multi-target license and option agreement with Vertex, pursuant to which the Company granted Vertex rights to the Company’s ADC technology to research and evaluate ADCs to specified targets, further details of which can be found in Note C, “Collaboration and License Agreements.”

The Company’s chief executive officer has served as a director on the board of directors of Ergomed PLC since June 2021. During the ~~nine~~three months ended ~~September 30,~~March 31, 2022, the Company executed agreements with Ergomed Clinical Research, Inc. and PrimeVigilance USA, Inc., subsidiaries of Ergomed PLC, for clinical trial and pharmacovigilance-related services. Ergomed Clinical Research, Inc. and PrimeVigilance USA, Inc. are each considered related parties pursuant to ASC 850, Related Party Disclosures. InDuring the ~~nine~~three months ended ~~September 30, 2022,~~March 31, 2023, the Company made payments totaling ~~$3.9~~$1.3 million to Ergomed Clinical Research, Inc. No similar payments were made during the three months ended March 31, 2022. Payments made pursuant to the agreement with PrimeVigilance USA, Inc. during the ~~nine~~three months ended ~~September 30,~~March 31, 2023 and 2022 were not material to the Company’s consolidated statement of operations.

J.L.Subsequent Events

The Company has evaluated all events or transactions that occurred after ~~September 30, 2022,~~March 31, 2023, up through the date the Company issued these financial statements. On April 6, 2023, the Company entered into an agreement with BioPharma Credit PLC as collateral agent, BPCR Limited Partnership, and BioPharma Credit Investments V (Master) LP, which are funds managed by Pharmakon Advisors, LP (collectively, Pharmakon), as lenders and the guarantors party to the agreement. The loan agreement provides for up to a $175.0 million senior secured term loan consisting of two tranches that each mature on April 6, 2028. The initial tranche of $75.0 million was drawn upon execution of the loan agreement. The second tranche of $50.0 million will be available at the Company’s option upon the achievement of positive top-line data from the Company’s confirmatory MIRASOL trial and a net sales threshold for ELAHERE. This tranche may be increased to $100.0 million upon mutual agreement of the parties. The term loan bears interest at a rate based upon the secured overnight financing rate (SOFR), subject to a SOFR floor of 2.75% per annum, plus 8.00% per annum. Payments will be interest-only for the first 36 months with an extension of 12 months if certain conditions are met, after which ratable principal payments will commence for the remainder of the term. The loan agreement contains customary affirmative and negative covenants for transactions of this type and includes certain customary events of default. If an event of default occurs and is continuing, the Company may be required to repay all amounts outstanding under the loan agreement. The term loan is secured by a perfected security interest on substantially all of the Company’s assets, excluding certain products and related intellectual property and contracts that are not related to ELAHERE.

The Company did not have any other material subsequent events.

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

The following information should be read in conjunction with the unaudited financial statements and the notes thereto included elsewhere in this report, and the consolidated financial statements and notes thereto for the year ended December 31, ~~2021,~~2022, and the related Management’s Discussion and Analysis of Financial Condition and Results of Operations contained in our Annual Report on Form 10-K for the year ended December 31, ~~2021,~~2022 filed with the ~~United States Securities and Exchange Commission, or the~~ SEC on ~~February 28, 2022.~~March 1, 2023.

OVERVIEW

We are a ~~clinical-stage~~commercial-stage biotechnology company focused on developing and commercializing the next generation of antibody-drug conjugates (ADCs) to improve outcomes for cancer patients. By generating targeted therapies with enhanced anti-tumor activity and favorable tolerability profiles, we aim to disrupt the progression of cancer and offer patients more good days. We call this our commitment to “target a better now.”

An ADC with our proprietary technology comprises an antibody that binds to a target found on tumor cells and is conjugated to one of our potent anti-cancer agents as a “payload” to kill the tumor cell once the ADC has bound to its target. ADCs are an expanding ~~approach to the treatment~~class of ~~cancer,~~anticancer therapeutics, with twelve approved products and the number of agents in development growing significantly in recent years.

We have established a leadership position in ADCs with a portfolio of differentiated product candidates to address both solid tumors and ~~hematological~~hematologic malignancies. We have set four strategic priorities for the business:

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execute the commercial launch for ELAHERE;

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expand the ELAHERE label by moving into platinum-sensitive ovarian cancer;

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advance our clinical pipeline of novel ADCs for hematologic and solid tumors; and

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strengthen and expand our pipeline through both internal discovery and external partnerships.

We believe that sound execution of these prioritized activities has the potential to create substantial short-and long-term value for shareholders, employees, patients, and other stakeholders in the Company.

~~Our business~~ELAHERE (Mirvetuximab Soravtansine)

~~Our lead program~~Approval and Launch

ELAHERE is ~~mirvetuximab soravtansine (MIRV),~~ a first-in-class ~~investigational~~ ADC targeting ~~FRα~~folate receptor alpha (FRα), a cell-surface protein over-expressed in a number of epithelial tumors, including ovarian, endometrial, and non-small-cell lung cancers. ~~Following consultation with~~On November 14, 2022, the FDA ~~we initiated two trials~~granted accelerated approval for ELAHERE for the treatment of ~~MIRV~~adult patients with FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have received one to three prior systemic treatment regimens. The accelerated approval of ELAHERE was based on efficacy and safety outcomes from SORAYA, a single-arm trial of ELAHERE in patients with platinum-resistant ovarian cancer whose tumors express high levels of FRα:. Continued approval may be contingent upon verification and description of clinical benefit in a confirmatory trial. Patients eligible for treatment with ELAHERE are selected by the VENTANA FOLR1 (FOLR1-2.1) RxDx Assay developed by RocheTissueDiagnostics, which was also approved by the FDA on November 14, 2022. We completed the build-out of our U.S. commercial infrastructure in 2022 and initiated sales in the U.S. in November 2022.

Ongoing Development

In addition to SORAYA, ~~a single-arm clinical trial that could lead to accelerated approval, pending FDA review; and~~we are conducting MIRASOL, a randomized Phase 3 clinical trial ~~that, if successful, could lead~~designed to support full approval ~~in this setting.~~of ELAHERE. In November 2021, we reported positive top-line data from SORAYA with an overall response rate (ORR) by investigator of 32.4%. At the Society of Gynecologic Oncology (SGO) 2022 Annual Meeting in March 2022, we reported the full data set from SORAYA, including the median duration of response of 6.9

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~~months.In March 2022, we~~ ~~submitted a biologics license application (BLA) to the FDA for acceleratedapproval~~of~~MIRV~~in~~secondthroughfourth-linepatientswithFRα~~-~~positive,platinum-resistantovariancancer.The FDA accepted the BLA under Priority Review designation~~ ~~in May 2022 and~~ set a Prescription Drug User Fee Act (PDUFA) action date of November 28, 2022. In June 2022, we presented additional efficacy and safety analyses from the MIRV program at the American Society of Clinical Oncology and in July 2022, we completed enrollment in MIRASOL and expect to report top-line data from this ~~study~~trial in early May 2023. If the MIRASOL trial is successful, we plan to submit a marketing authorisation application for approval of ELAHERE for the treatment of adult patients with FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have received one to three prior systemic treatment regimens to the EMA in the second half of 2023. Additionally, our partner, Huadong, expects to submit a biologics license application to the National Medical Products Administration (NMPA) of China for ELAHERE in the same indication in the second half of 2023 to support potential approval and launch of ELAHERE in Greater China in 2024.

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Beyond platinum-resistant ovarian cancer,, ourstrategyisto~~develop and investigateMIRVfor~~ move ELAHERE into platinum-sensitive disease, ~~with the goal~~and to position the product as the combination agent of choice in ovarian cancer.Tothisend, in January 2023, we ~~initiated~~completed patient enrollment in PICCOLO, a single-arm ~~study~~trial of ~~MIRV~~ELAHERE monotherapy in later-line FRα positive platinum-sensitive ~~patients.~~patients, and plan to report on the primary endpoint before the end of 2023. We have also generated encouraging data in recurrent platinum-sensitive disease with the combination of ~~MIRV~~ELAHERE plus carboplatin and we aresupportinginvestigator sponsored trials (~~ISTs)~~(ISTs) with this combination inasingle-arm~~study~~ trial intheneoadjuvantsettingandinarandomized~~study~~ trial comparing~~MIRV~~ ELAHERE combinedwith carboplatin to standard of care in patients with recurrent platinum-sensitive disease. We ~~are~~ also ~~initiating a~~continued enrollment in the single-arm Phase 2 ~~study~~trial (0420) of this combination followed by ~~MIRV~~ELAHERE continuation in FRα-low, medium, and high patients with platinum-sensitive disease. Results from this ~~study~~trial and our ongoing ISTs will inform a path to the potential registration for ~~MIRV~~ELAHERE plus carboplatin and, in parallel, could support compendia listing for this combination.

~~In addition,~~we~~have generated data fromourPhase~~1b~~FORWARD~~II~~trial~~of~~MIRVplusAVASTIN~~^® ~~(bevacizumab) in recurrent ovarian cancer and believe these data could support compendia listing for this combination in close proximity to the initial monotherapy approval of MIRV. Furthermore,~~ Finally, we have ~~designed~~initiated GLORIOSA, a randomized Phase 3 ~~study~~trial of ~~MIRV~~ELAHERE plus bevacizumab maintenance in FRα-high recurrent platinum-sensitive disease ~~based on FDA feedback and have initiated this study, which~~that we believe could support ~~potential~~ label expansion.

Pivekimab Sunirine

Pivekimab sunirine (PVEK), ~~our product candidate~~ formerly known as IMGN632, is an ADC comprised of a high-affinity antibody designed to target CD123 with site-specific conjugation to a DNA-alkylating payload of the novel IGN ~~(indolinobenzodiazepine~~(indolinobenzodiazepine pseudodimer) class. OurIGNsaredesignedtoalkylateDNAwithoutcross-linking,whichhasprovidedabroadtherapeuticindex in preclinical models. We are advancing PVEK in clinical trials for patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN) and acute myeloid leukemia (AML).

BPDCN is a rare form of blood cancer, with an annual incidence of between 500 and 1,000 patients in the US. In October 2020, the FDAgrantedBreakthroughTherapydesignationforPVEKforthetreatmentofpatientswithrelapsed or refractory BPDCN. Based on feedback from the FDA, we amended our ongoing 801 Phase 2 ~~study,~~trial, knownas~~CADENZA,~~to~~include~~a~~newcohort~~ofupto20~~frontline~~ ~~BPDCN~~ ~~patients.~~

~~The~~ CADENZA, ~~study enrolled~~to include a new cohort of up to 20 frontline BPDCN ~~patients with~~patients.

Initial enrollment in CADENZA did not distinguish between de novo ~~disease~~BPDCN patients and those who presented with a prior or concomitant hematologic malignancy (PCHM). Although complete responses have been observed in BPDCN patients who present with PCHM, most will not achieve full hematologic recovery due to the impact of their prior or concomitant malignancy. For these patients, we believe that achieving a complete response with partial hematological recovery (CRh) is a potentially important measure of clinical benefit.

In data from the first ten patients in the pivotal CADENZA frontline cohort, we observed: 2 of 4 de novo patients achieved CR (complete response)/CRc (clinical complete response); and 4 of 6 PCHM patients achieved CR/CRc/CRh. In addition, in three frontline patients (2 de novo, 1 PCHM) enrolled prior to the opening of the pivotal cohort, all three patients achieved CR/CRc.

A Type B meeting was held in August 2022 regarding ~~these~~the initial data from the CADENZA ~~study.~~trial. Based on FDA feedback on ~~study~~trial design provided in this meeting, the efficacy analysis will be conducted in de novo BPDCN patients with ~~CR/~~CR (complete response)/CRc (clinical complete response) as the primary endpoint and the key secondary endpoint of duration of CR/CRc. We will enroll up to 20 de novo patients for purposes of the efficacy analysis. We will also continue to enroll PCHM patients in CADENZA to further evaluate PVEK in this population. ~~Given this is an ultra-rare disease, the~~The Company expects to report top-line data on the primary and key secondary endpoints in 2024.

We are also conducting our802~~study~~ trial for PVEK,,whichisaPhase1b/2~~study~~ trial designedtodeterminethesafety,tolerability,andpreliminary antileukemia activity of PVEK when administered in combination with azacytidine and venetoclax to patients with relapsed and frontline CD123-positive AML. Having identified the recommended Phase 2

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dose for the triplet, patients are accruing in both expansion ~~cohorts~~cohorts. In December 2022, safety and ~~we expect to share~~efficacy findings in relapsed refractory AML and initial data ~~from these cohorts~~in frontline AML was presented at the American Society of Hematology Annual ~~Meeting later this year.~~

Meeting. In the first 10 frontline patients enrolled, 5/10 (50%) patients achieved a CR and 3/4 (75%) patients tested had a minimal residual disease (MRD)-negative CR. Based upon these results, the Company will continue enrollment in two frontline AML expansion cohorts to optimize the duration of venetoclax therapy. In addition, ~~we are advancing~~in December 2022, the Company announced a clinical collaboration with Gilead Sciences, Inc. to study PVEK in combination with magrolimab in relapsed refractory AML and expects to initiate this cohort under the 802 trial in the second half of 2023.

Other Pipeline Programs

We continue to advance our earlier-stage pipeline programs. IMGC936 is an ADC in co-development with MacroGenics,Inc.thatisdesignedtotargetADAM9,anenzymeover-expressedinarangeofsolidtumors and implicated in tumor progression and metastasis. IMGC936 incorporates a number of innovations, including antibody engineering to extend half-life, site-specific conjugation with a fixed drug-antibody ratiotoenablehigherdosing,~~and~~a~~next-generationlinkerandpayloaddesignedforimprovedstability~~and a next-generation linker and payload designed for improved stability and bystander activity. Phase 1 dose escalation was completed and

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We ~~continue to enroll patients~~expansion cohorts in non–small cell lung cancer (NSCLC) and triple-negative breast cancer initiated in the ~~Phase 1 study for this program~~second half of 2022. Since then, we have prioritized the NSCLC cohort and ~~expect initial data in~~ the ~~fourth quarter of~~ ~~2022.~~Company expects to provide an update after an interim analysis.

IMGN151 is our next generation anti-FRα product candidate in development. This ADC integrates innovation in each of its components, which we believe may enable IMGN151 to address patientpopulationswithlowerlevelsofFRαexpression,includingtumortypesoutsideofovarian~~cancer. In January 2022, we submitted an IND application to evaluate IMGN151~~ cancer. We began enrollment in a ~~planned~~ Phase 1 clinical trial evaluating IMGN151 in patients with recurrent endometrial cancer and recurrent, high-grade serous epithelial ovarian, primary peritoneal, or fallopian tube cancers. In February 2022, the FDA placed a hold on our IND application pending responses to certain chemistry, manufacturing, and controls information requests. We submitted responses, have received a “Study-May-Proceed” letter from FDA, and anticipate enrolling our first patientcancers in ~~the fourth quarter of 2022.~~January 2023.

We have selectively licensed restricted access to our ADC platform technology to other companies to expand the use of our technology and to provide us with cash to fund our own product programs. These agreements typically provide the licensee with rights to use our ADC platform technology with its antibodies or related targeting vehicles to a defined target to develop products. The licensee is generally responsible for the development, clinical testing, manufacturing, registration, and commercialization of any resulting product candidate. As part of these agreements, we are generally entitled to receive upfront fees, potential milestone payments, and royalties on the sales of any resulting products.

In February 2022, we entered into a license agreement with Lilly, pursuant to which the Company granted Lilly worldwide exclusive rights to research, develop, and commercialize ADCs based on the Company’s novel camptothecin technology. Additionally, in June 2022, we entered into a research collaboration agreement with OBT to develop novel ADCs utilizing the Company’s linker-payload technology directed to targets identified via OBT's proprietary OGAP^® discovery platform. After antibodies generated by OBT have been conjugated with ImmunoGen's proprietary linker-payload technology, each company will have the opportunity to select one or more development programs to further develop on its own. For more information concerning these relationships, including their ongoing financial and accounting impact on our business, please read Note C, ~~“Significant Collaborative~~“Collaboration and License Agreements,~~” and Note H, “Commitments and Contingencies,~~” to our consolidated financial statements included in this report.

~~As of September 30, 2022, we have not generated revenues from commercial sales of internal products, and we~~We expect to continue to incur substantial operating losses for at least the near term as we incur significant operating expenses related to research and development and ~~the commercialization~~selling and marketing of ~~our portfolio over the next several years.~~ELAHERE. As of ~~September 30, 2022,~~March 31, 2023, we had ~~$309.5~~$201.2 million in cash and cash equivalents compared to ~~$478.8~~$275.1 million as of December 31, 2021. We expect to raise additional funds through equity, debt, and other financings or generate revenues from product sales of MIRV, if approved, as well as revenues from collaborations through a combination of upfront license payments, milestone payments, royalty payments, and research funding to support our planned operating activities. We cannot provide assurance that we will be able to obtain additional debt, equity, or other financing or generate revenues from product sales of MIRV, if approved, or from collaborations on terms acceptable to us or at all. The failure to obtain sufficient funds on acceptable terms when needed could have a material adverse effect on our business, results of operations, and financial condition and require us to defer or limit some or all of our research, development, and/or clinical projects, including trials to support potential label expansion of MIRV.

~~Managing the impact of the COVID-19 pandemic~~

Since the first quarter of 2020, although we have experienced some delays or disruptions due to the COVID-19 pandemic, we have successfully continued to move our clinical studies forward while adapting to meet the evolving challenges of the pandemic. We implemented business continuity plans in March 2020 that enabled our workforce to remain productive while working from home until mid-September 2021, at which time our workforce returned to the office. From a regulatory perspective, since the beginning of the pandemic, we have received timely reviews of our submissions to the FDA and other health authorities covering our clinical trial applications, as well as timely acceptance by the FDA of our BLA submitted in March 2022 for accelerated approval of MIRV. From a manufacturing and supply

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~~chain perspective, we believe we have sufficient inventory on hand for all of our ongoing and near-term studies and to support the launch of MIRV, if approved.~~2022.

Critical accounting policies and estimates

We prepare our consolidated financial statements in accordance with accounting principles generally accepted in the U.S. The preparation of these financial statements requires us to make certain estimates and judgments that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reported periods. These items are monitored and analyzed by management for changes in facts and circumstances, and material changes in these estimates could occur in the future. Changes in estimates are reflected in reported results for the period in which the change occurs. We base our estimates on historical experience and various other assumptions that we believe to be reasonable under the circumstances. Actual results may differ from our estimates if past experience or other assumptions do not turn out to be substantially accurate.

We believe that our application of the following accounting policies, each of which requires significant judgments and estimates on the part of management, are the most critical to aid in fully understanding and evaluating our reported financial results:

●

inventory capitalization;

●

revenue recognition;

●

clinical trial accruals; and

●

stock-based compensation.

During the three ~~and nine~~ months ended ~~September 30, 2022,~~March 31, 2023, there were no material changes to our critical accounting policies and estimates as reported in our Annual Report on Form 10-K for the year ended December 31, ~~2021,~~2022 filed with the SEC on ~~February 28, 2022.~~March 1, 2023.

Managing the impact of the COVID-19 pandemic

Since the first quarter of 2020, although we have experienced some delays or disruptions due to the COVID-19 pandemic, we have successfully continued to move our clinical trials forward while adapting to meet the evolving challenges of the pandemic. We implemented business continuity plans in March 2020 that enabled our workforce to remain productive while working from home until mid-September 2021, at which time our workforce returned to the office. From a regulatory perspective, since the beginning of the pandemic, we have received timely reviews of our submissions to the FDA and other health authorities covering our clinical trial applications. From a manufacturing and supply chain perspective, we believe we have sufficient inventory on hand for all of our ongoing and near-term clinical

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trials and to support the continued commercialization of ELAHERE. COVID-19 may impact our commercial activities for ELAHERE, including patient access to testing and identification; in that event, we would conduct commercial and medical affairs field activities in virtual formats where in-person interactions are not feasible.

RESULTS OF OPERATIONS

Revenues

For the three months ended ~~September 30, 2022,~~March 31, 2023, our total revenues increased ~~$6.2~~$11.8 million compared to the three months ended ~~September 30, 2021,~~March 31, 2022, driven by ~~increases~~net product sales of ELAHERE in the current period, partially offset by decreases in license and milestone fees and non-cash royalty revenue. For the nine months ended September 30, 2022, our total revenues increased $25.8 million compared to the nine months ended September 30, 2021, driven primarily by an increase in license and milestone fees, partially offset by lower non-cash royalty revenue. See further discussion below.

Product revenue, net

On November 14, 2022, the FDAgrantedacceleratedapprovalforELAHEREforthetreatmentof adult patients with FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritonealcancer,whohavereceivedonetothreepriorsystemictreatmentregimens. We recorded $29.5 million of net product revenue related to U.S. sales of ELAHERE in the three months ended March 31, 2023.

License and milestone fees

The amount of license and milestone fees we earn is directly related to the number of our collaborators, the advancement of product candidates covered by the agreements with our collaborators, and the overall success in the clinical trials of these product candidates. As such, the amount of license and milestone fees recognized may vary significantly from quarter to quarter and year to year. License and milestone fee revenue ~~increased $4.7 million and $42.2~~decreased $15.9 million in the three ~~and nine~~ months ended ~~September 30, 2022, respectively,~~March 31, 2023 compared to the three ~~and nine~~ months ended ~~September 30, 2021.~~March 31, 2022. Driving the ~~increases,~~decrease, during the three months ended March 31, 2022, we recorded as revenue $21.6 million of previously received and deferred payments pursuant to our license agreement with Huadong ~~executed in October 2020, upon delivery of clinical supply in the nine months ended September 30, 2022, we recognized $28.5~~and $9.2 million of ~~the remaining deferred revenue balance as of December 31, 2021 related to~~a $13.0 million upfront ~~and development milestone payments previously received. Additionally,~~payment received pursuant to a multi-target license agreement executed with Lilly in February 2022, ~~during~~which did not recur in the three ~~and nine~~ months ended ~~September 30, 2022,~~March 31, 2023. During the three months ended March 31, 2023, we ~~recognized $4.6~~received and recorded as revenue a $15.0 million upfront payment pursuant to a multi-target license and ~~$13.8 million, respectively, of upfront payments received.~~option agreement executed with Vertex in February 2023.

Non-cash royalty revenue related to the sale of future royalties

KADCYLA^® is a marketed ADC resulting from one of our development and commercialization licenses with Roche, through its Genentech unit. We receive royalty reports and payments related to sales of KADCYLA from Roche one quarter in arrears. We sold our rights to receive royalty payments on the net sales of KADCYLA through two separate transactions in 2015 and 2019. In accordance with our revenue recognition policy, ~~$8.0 million and $21.5~~$4.8 million of non-cash royalties on net sales of KADCYLA were recorded and included in non-cash royalty revenue for the three ~~and nine~~ months ended ~~September 30, 2022, respectively,~~March 31, 2023 compared to ~~$6.5 million and $38.8~~$6.4 million in non-cash royalty revenue

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recorded for the three ~~and nine~~ months ended September 30, 2021, respectively. The decrease in non-cash royalty revenue for the nine months ended September 30, 2022 compared to the prior nine-month period is a result of the aggregate royalty threshold, as outlined in the 2015 royalty purchase agreement, being met in the second quarter of 2021, effectively reducing the royalty payments under the 2015 transaction from 100% to 15% of KADCYLA royalty payments received over the remaining royalty term. Pursuant to the terms of these agreements, we expect to recognize less non-cash royalty revenue in 2022 and subsequent years as compared to 2021 and prior years.March 31, 2022. See further details regarding these agreements in Note F, “Liability Related to Sale of Future Royalties,” of the Consolidated Financial Statements.

Cost of Sales

Our cost of sales includes the cost of producing and distributing inventories that are related to product revenue, including freight. In addition, shipping and handling costs for product shipments are recorded as incurred. Finally, cost of sales may also include costs related to excess or obsolete inventory adjustment charges.

Prior to receiving FDA accelerated approval for ELAHERE in November 2022, we manufactured inventory to be sold upon commercialization and recorded the costs as research and development expense. As a result, the manufacturing costs related to the inventory manufactured prior to receiving FDA accelerated approval were expensed in a prior period and are therefore excluded from the cost of goods sold for the three months ended March 31, 2023. We estimate our cost of sales related to product revenue as a percentage of net product revenue will continue to be positively affected as we sell through certain inventory that was previously expensed prior to FDA approval. We expect to utilize zero and low-cost inventory for an extended period of time.

Research and development expenses

Our research and development expenses relate to (i) research to evaluate new targets and to develop and evaluate new antibodies, linkers, and cytotoxic agents, (ii) preclinical testing of our own and, in certain instances, our

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collaborators’ product candidates, and the cost of our own clinical trials, (iii) development related to clinical and commercial manufacturing processes, (iv) regulatory activities, (v) medical affairs activities, and (vi) external manufacturing operations.

We do not track our research and development costs by project. Since we use our research and development resources across multiple research and development projects, we manage our research and development expenses within each of the categories listed in the following table and described in more detail below (in thousands):


	Three Months Ended						Nine Months Ended						Three Months Ended
	September 30,				Increase/		September 30,				Increase/		March 31,				Increase/
Research and Development Expenses	2022		2021		(Decrease)		2022		2021		(Decrease)		2023		2022		(Decrease)
Research	$	560	$	—	$	560	$	8,060	$	—	$	8,060	$	1,358	$	—	$	1,358
Preclinical and clinical testing		39,394		23,484		15,910		102,664		72,095		30,569		38,320		31,495		6,825
Process and product development		2,086		2,030		56		5,261		4,898		363		2,919		1,461		1,458
Manufacturing operations		17,141		7,633		9,508		38,900		25,156		13,744		9,023		11,326		(2,303)
Total research and development expenses	$	59,181	$	33,147	$	26,034	$	154,885	$	102,149	$	52,736	$	51,620	$	44,282	$	7,338

Research

Research includes expenses to evaluate new targets and to develop and evaluate new antibodies, linkers, and cytotoxic agents. Such expenses include third-party license fees, research funding payments, and contract services. Pursuant to a research collaboration agreement executed with ~~OBT~~Oxford BioTherapeutics Ltd. in June 2022, we recognized ~~$0.6~~$1.2 million of committed research costs in the three months ended ~~September 30, 2022 and a $7.5 million upfront license fee as expense in the nine months ended September 30, 2022.~~March 31, 2023. No similar expenses were recorded in the three ~~and nine~~ months ended ~~September 30, 2021.~~March 31, 2022.

Preclinical and clinical testing

Preclinical and clinical testing includes expenses related to preclinical testing of our own, and, in certain instances, our collaborators’ product candidates, regulatory activities, the cost of clinical trials, and expenses related to medical affairs. Such expenses include the costs of personnel, third-party staffing, patient enrollment at our clinical testing sites, consultant fees, contract services, and facility expenses. In the three ~~and nine~~ months ended ~~September 30, 2022,~~March 31, 2023, preclinical and clinical testing expenses increased by ~~$15.9~~$6.8 million ~~and $30.6 million, respectively,~~ compared to the three ~~and nine~~ months ended ~~September 30, 2021,~~March 31, 2022, due primarily to ~~increases~~costs related to increased headcount to support the advancement of ELAHERE, including an expanded medical affairs team, and an increase in ~~personnel, third-party staffing costs, and~~ clinical trial costs driven by our ~~MIRV~~ELAHERE, PVEK, and ~~PVEK studies, as well as an increase in contract services driven by medical affairs’ activities in support of advancing MIRV.~~IMGN151 trials.

Process and product development

Process and product development expenses include costs for development of clinical and commercial manufacturing processes for our own and collaborator compounds. Such expenses include the costs of personnel, third-party staffing, contract services, and facility expenses. In the three ~~and nine~~ months ended ~~September 30, 2022,~~March 31, 2023, process and product development expenses increased by ~~$0.1~~$1.5 million ~~and $0.4 million, respectively,~~ compared to the three ~~and nine~~ months ended ~~September 30, 2021,~~March 31, 2022, due primarily to increased personnel-related ~~costs.~~costs and third-party contract services related to advancing early-stage programs.

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Manufacturing operations

Manufacturing operations expense includes costs to have preclinical and clinical materials manufactured for our product candidates and quality control and quality assurance activities. Such expenses include personnel, third-party staffing, raw materials for our preclinical studies and clinical trials, non-pivotal and pivotal development costs with contract manufacturing organizations, and facility expenses. In the three ~~and nine~~ months ended ~~September 30, 2022,~~March 31, 2023, manufacturing operations expense ~~increased~~decreased by ~~$9.5~~$2.3 million ~~and $13.7 million, respectively,~~ compared to the three ~~and nine~~ months ended ~~September 30, 2021,~~March 31, 2022, due primarily to greater raw materials produced for use in the manufacture and sale of ELAHERE in the prior year period, which were expensed where produced prior to FDA accelerated approval, partially offset by increases in personnel-related costs and external manufacturing activity across our other internal programs.

Selling, general and administrative expenses

Selling, general and administrative expenses consist primarily of personnel-related costs, including stock-based compensation, for commercial operations and for personnel in executive, finance, accounting, business development, information technology, legal, and human resources functions. Other significant costs include facility costs not otherwise

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included in research and development expenses, commercial development activities, legal fees related to intellectual property and corporate matters, and fees for accounting and consulting services.

In the three ~~and nine~~ months ended ~~September 30, 2022,~~March 31, 2023, selling, general and administrative expenses increased by ~~$23.3~~$23.4 million ~~and $43.8 million, respectively,~~ compared to the three ~~and nine~~ months ended ~~September 30, 2021~~March 31, 2022 due primarily to ~~building our commercial capabilities,~~greater expenses in support of advancing the U.S. launch of ELAHERE, including personnel-related costs and sales and marketing activities.

Investment income

Investment income for the three months ended March 31, 2023 and 2022 was $2.2 million and $0.1 million, respectively. The increase in ~~preparation for~~2023 was driven by a ~~potential U.S. launch of MIRV~~significant increase in ~~the fourth quarter of 2022.~~interest rates.

Non-cash interest expense on liability related to the sale of future royalties

In 2015, IRH purchased our right to receive 100% of the royalty payments on commercial sales of KADCYLA arising under our development and commercialization license with Genentech, subject to a residual cap. In January 2019, OMERS purchased IRH’s right to the royalties the Company previously sold in 2015. As described in Note E,F, “Liability Related to Sale of Future Royalties,” to our consolidated financial statements included in this report, this royalty sale transaction has been recorded as a liability that amortizes over the estimated royalty payment period as KADCYLA royalties are remitted directly to the purchaser. During the three ~~and nine~~ months ended ~~September 30, 2022,~~March 31, 2023, we recorded $0.9 million ~~and $3.2 million~~ of non-cash interest expense ~~respectively,~~ which includes amortization of deferred financing costs, compared to ~~$2.8 million and $11.0~~$1.3 million recorded in the three ~~and nine~~ months ended ~~September 30, 2021.~~March 31, 2022. The decrease was a result of a lower average royalty liability balance for the period and the KADCYLA royalty threshold being met in the second quarter of 2021, effectively reducing the royalty payments under the 2015 transaction from 100% to 15% of KADCYLA royalty payments received over the remaining royalty term.period.

LIQUIDITY AND CAPITAL RESOURCES

The tables below summarize our cash and cash equivalents, working capital, and shareholders’ equity as of ~~September 30, 2022~~March 31, 2023 and December 31, ~~2021,~~2022, and cash flow activities for the ~~nine~~three months ended ~~September 30,~~March 31, 2023 and 2022 ~~and 2021~~ (in thousands):


	As of				As of
	September 30,		December 31,		March 31,		December 31,
	2022		2021		2023		2022
Cash and cash equivalents	$	309,511	$	478,750	$	201,249	$	275,138
Working capital		226,774		399,054		142,235		182,263
Shareholders’ equity		178,007		325,586		121,918		155,826


	Nine Months Ended September 30,				Three Months Ended March 31,
	2022		2021		2023		2022
Cash used for operating activities	$	(169,603)	$	(123,542)	$	(73,719)	$	(41,402)
Cash used for investing activities		(1,116)		(1,065)		(209)		(307)
Cash provided by financing activities		1,480		76,512		39		620

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Cash flows

We require cash to fund our operating expenses, including the advancement of our clinical programs and to make capital expenditures. Historically, we have funded our cash requirements primarily through equity and convertible debt financings in private and public markets and payments from our collaborators, including license fees, milestone payments, research funding, and ~~royalties.~~royalties, and more recently, through commercial sales of ELAHERE. We have also monetized our rights to receive royalties on KADCYLA for upfront consideration. As of ~~September 30, 2022,~~March 31, 2023, we had ~~$309.5~~$201.2 million in cash and cash equivalents. Net cash used for operations was ~~$169.6~~$73.7 million and ~~$123.5~~$41.4 million for the ~~nine~~three months ended ~~September 30,~~March 31, 2023 and 2022, ~~and 2021,~~ respectively. The principal use of cash for operating activities for both periods presented was to fund our net loss, adjusted for non-cash ~~items, with the nine months ended September 30, 2022 benefiting from $19.5 million of upfront payments pursuant to a license agreement with Lilly.~~items.

Net cash used for investing activities was ~~$1.1~~$0.2 million and $0.3 million for ~~each of~~ the ~~nine~~three months ended ~~September 30,~~March 31, 2023 and 2022, ~~and 2021,~~respectively, consisting of cash outflows for capital expenditures in both ~~periods, including computer and office equipment and dedicated equipment at third-party manufacturing vendors.~~periods.

Net cash provided by financing activities was ~~$1.5 million~~$39,000 and ~~$76.5~~$0.6 million for the ~~nine~~three months ended ~~September 30,~~March 31, 2023 and 2022, ~~and 2021, respectively. Net cash provided by financing activities for the nine months ended September 30, 2022 and 2021 includes $1.5 million and $2.0 million,~~ respectively, consisting of proceeds from the exercise of stock options. ~~During the nine months ended September 30, 2021,~~

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In April 2023, we entered into a ~~Securities Purchase Agreement~~loan agreement with ~~RA Capital Healthcare Fund, L.P. (RA Capital) pursuant to~~BPCR Limited Partnership and BioPharma Credit Investments V (Master) LP, which ~~the Company agreed to sell to RA Capital a pre-funded warrant to purchase~~are funds managed by Pharmakon Advisors, LP (collectively, Pharmakon) which provides for up to ~~an aggregate~~a $175.0 million senior secured term loan consisting of ~~5,434,782 shares~~two tranches that each mature on April 6, 2028. The initial tranche of $75.0 million was drawn upon execution of the ~~Company’s common stock,~~loan agreement, resulting in proceeds net ~~proceeds~~ of ~~$29.8~~fees and expenses of approximately $72.0 million. ~~Additionally, during 2021, we sold 6,694,600 shares~~The second tranche of $50.0 million will be available at our ~~common stock under~~option upon the achievement of positive top-line data from our ~~Open Market Sale Agreement~~^SMconfirmatory MIRASOL trial and a net sales threshold for ELAHERE. This tranche may be increased to $100.0 million upon mutual agreement of the parties. The term loan bears interest at a rate based upon the secured overnight financing rate (SOFR), subject to a SOFR floor of 2.75% per annum, plus 8.00% per annum. Payments will be interest-only for the first 36 months with ~~Jefferies, LLC as sales agent, dated December 18, 2020, generating net proceeds~~an extension of ~~$45.8 million. Partially offsetting these cash inflows,~~ ~~$1.1 million~~12 months if certain conditions are met, after which ratable principal payments will commence for the remainder of ~~convertible 4.5% senior notes were paid in cash upon maturity on July 1, 2021.~~the term.

Future Capital Requirements

We have significant future capital requirements including:

●

significant expected operating expenses to commercialize ELAHERE;

●

significant expected operating expenses to conduct research and development activities and to potentially commercialize our portfolio;

●

noncancelable in-process and future manufacturing ~~obligations;~~obligations, including commercial supply of ELAHERE; and

●

substantial facility lease obligations as described in Note J,K, “Leases,” included in our Annual Report on Form 10-K for the year ended December 31, ~~2021,~~2022, and as described in Note G,I, “Leases,” included in this Quarterly Report on Form 10-Q.

We anticipate that our current capital resources will enable us to meet our operational expenses and capital requirements for more than twelve months after the date of this report. We expect to ~~raise~~generate additional funds through a combination of commercial sales of ELAHERE, equity ~~debt, and~~or other financings, ~~or generate revenues from product sales of MIRV, if approved,~~such as ~~well as~~royalty financing transactions, additional debt pursuant to the current term loan facility, and revenues from collaborations, ~~through a combination of~~including upfront license payments, milestone payments, royalty payments, and research funding, to support our planned operating activities. We cannot provide assurance that we will be able to obtain additional debt, equity, or other financing or generate revenues from product sales of MIRV, if approved, or from collaborations on terms acceptable to us or at all.activities; however, such activities may not succeed. The failure to ~~obtain~~generate sufficient funds on acceptable terms ~~when needed~~ could have a material adverse effect on our business, results of operations, and financial condition and require us to defer or limit some or all of our research, development, clinical, and/or ~~clinical~~commercial projects, including trials to support potential label expansion of ~~MIRV.~~ELAHERE.

Recent Accounting Pronouncements

The information set forth under Note B, ~~“Summary~~“Basis of Presentation and Significant Accounting Policies,” to our consolidated financial statements included in this report under the caption “Recently Adopted Accounting Pronouncements” is incorporated herein by reference.

Third-Party Trademarks

KADCYLA^® ~~and AVASTIN~~^® ~~are registered trademarks of Genentech, Inc. OGAP~~^®is a registered trademark of ~~Oxford BioTherapeutics Ltd.~~Genentech, Inc.

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ITEM 3. Quantitative and Qualitative Disclosure about Market Risk

Our market risks, and the ways we manage them, are summarized in Part II, Item 7A, “Quantitative and Qualitative Disclosures About Market Risk” of our Annual Report on Form 10-K for the year ended December 31, ~~2021,~~2022, filed with the SEC on ~~February 28, 2022 and there~~March 1, 2023. There have been no material changes to our market risks, or to our management of such risks, as set forth in such Annual Report on Form 10-K.

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ITEM 4. Controls and Procedures

(a)	Disclosure Controls and Procedures

Our management, with the participation of our principal executive and principal financial officers, has evaluated the effectiveness of our disclosure controls and procedures (as defined in Rules 13a-15(e) or 15d-15(e) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) as of the end of the period covered by this report. Based on such evaluation, our principal executive and principal financial officers have concluded that, as of the end of such period, our disclosure controls and procedures were effective.

(b)	Changes in Internal Controls Over Financial Reporting

During the three months ended March 31, 2023, we implemented certain internal controls in connection with product revenue. There were no other changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15(d)-15(f) under the Exchange Act) that occurred during the period covered by this report that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

PART II. OTHER INFORMATION

ITEM 1A. Risk Factors

In addition to the other information set forth in this report, you should carefully review and consider the information regarding certain factors that could materially affect our business, financial condition, or future results set forth under Item 1A. “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, ~~2021, filed with the SEC on February 28, 2022, and our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2022 and June 30,~~ 2022 filed with the SEC on ~~May 6, 2022 and August~~March 1, ~~2022, respectively.~~2023. There have been no material changes from the factors disclosed in our Annual Report on Form 10-K for the year ended December 31, ~~2021 or Quarterly Reports on Form 10-Q for~~2022, other than the ~~quarters ended March 31, 2022 and June 30, 2022.~~risk factors included below. We may, however, disclose changes to such risk factors, or disclose additional risk factors, from time to time in our future filings with the SEC.

Unfavorable global economic conditions, as well as regional conflicts, could adversely affect our business, financial condition, and results of operations.

Our results of operations could be adversely affected by general conditions in the global economy and in the global financial markets. For example, the global economy has experienced extreme volatility and disruptions, including significant volatility in commodity and market prices, declines in consumer confidence, declines in economic growth, supply chain interruptions, uncertainty about economic stability, and inflation. More recently, the closures of Silicon Valley Bank and Signature Bank and their placement into receivership with the Federal Deposit Insurance Corporation (FDIC) created bank-specific and broader financial institution liquidity risk and concerns. Although the Department of the Treasury, the Federal Reserve, and the FDIC jointly released a statement that depositors at Silicon Valley Bank and Signature Bank would have access to their funds, even those in excess of the standard FDIC insurance limits, under a systemic risk exception, future adverse developments with respect to specific financial institutions or the broader financial services industry may lead to market-wide liquidity shortages, impair the ability of companies to access near-term working capital needs, and create additional market and economic uncertainty. There can be no assurance that future credit and financial market instability and a deterioration in confidence in economic conditions will not occur. Our general business strategy may be adversely affected by any such economic downturn, liquidity shortages, volatile business environment or continued unpredictable and unstable market conditions. If the equity and credit markets deteriorate, or if financial institutions experience adverse developments, it may cause short-term liquidity risk. Unfavorable economic conditions could result in a variety of risks to our business, including demand and pricing for our products, difficulty in forecasting our financial results, and our ability to raise additional capital when needed and on acceptable terms. A weak or declining economy could also strain our suppliers, possibly resulting in supply chain disruptions. These and other economic factors or regional conflicts could adversely affect our business and results of operations.

We have outstanding indebtedness in the form of a term loan and may incur additional indebtedness in the future, which could adversely affect our financial position and prevent us from implementing our business strategy.

In April 2023, we entered into a loan agreement with certain funds managed by Pharmakon Advisors, LP, which provides for a term loan facility for up to $175.0 million. The loan agreement contains customary affirmative and negative covenants for this transaction type, including certain restrictions on the ability to incur indebtedness and grant liens or

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security interests on assets, which could impose significant restrictions on our ability to operate and engage in acts that may be in our long-term best interest. The term loan is also secured by a perfected security interest on substantially all of the Company’s assets, excluding certain products and related intellectual property and contracts that are not related to ELAHERE. A breach of any of the covenants or clauses under the loan agreement could result in a default under the loan agreement, which could cause all of the outstanding indebtedness under the facility to become immediately due and payable. In addition, if we are unable to pay our obligations under the loan agreement, the lenders could proceed against the collateral granted to them, which could restrict our ability to commercialize ELAHERE and adversely affect our business and results of operations. Our ability to pay principal or interest on the loan agreement depends on our future performance, which is subject to economic, financial, competitive, and other factors, some of which are beyond our control. Our business may not generate cash flow from operations in the future sufficient to satisfy any obligations under the loan agreement or under any future indebtedness we may incur. If we are unable to generate such cash flow, we may be required to delay, restrict, or eliminate all or a portion of our development programs or commercialization efforts or obtain additional financing on terms that may be onerous or highly dilutive. If we do not meet our debt obligations, it could materially adversely affect our business and results of operations.

ITEM 6. Exhibits

Exhibit No.		Description
10.1	*	License and Option Agreement dated as of February 28, 2023 by and between ImmunoGen, Inc. and Vertex Pharmaceuticals Incorporated
10.2	*	Loan Agreement, dated as of April 6, 2023, by and among ImmunoGen, Inc. as the borrower, and certain subsidiaries of the Company party thereto from time to time, as guarantors, BPCR Limited Partnership, as a lender, BioPharma Credit Investments V (Master) LP, as a lender, and BioPharma Credit PLC, as collateral agent for the lenders
31.1		Certification of the principal executive officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
31.2		Certification of the principal financial officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
32	†	Certifications of the principal executive officer and the principal financial officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
101		Financial statements from the quarterly report on Form 10-Q of ImmunoGen, Inc. for the quarter ended ~~September 30, 2022~~March 31, 2023 formatted in inline XBRL (eXtensible Business Reporting Language): (i) the Consolidated Balance Sheets; (ii) the Consolidated Statements of Operations and Comprehensive Loss; (iii) the Consolidated Statements of Shareholder’s Equity (Deficit); (iv) the Consolidated Statements of Cash Flows; and (v) the Notes to Consolidated Financial Statements
104		Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

* Certain confidential portions of this exhibit were omitted by means of marking such portions with brackets [***] because the identified confidential portions (i) are not material and (ii) is the type of information the Registrant treats as private or confidential.

†	Furnished, not filed.

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SIGNATURES

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

	ImmunoGen, Inc.

Date: ~~November 4, 2022~~April 28, 2023	By:	/s/ Mark J. Enyedy
		Mark J. Enyedy
		President and Chief Executive Officer (Principal Executive Officer)

Date: ~~November 4, 2022~~April 28, 2023	By:	/s/ ~~Susan Altschuller, Ph.D.~~Renee Lentini
		~~Susan Altschuller, Ph.D.~~Renee Lentini
		~~Senior~~ Vice President - Finance, Chief Accounting Officer, and Interim Chief Financial Officer (Principal Accounting Officer and Principal Financial Officer)

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	Three Months Ended September 30,		Nine Months Ended September 30,
	2022	2021	2022	2021
Dividend	None	None	None	None
Volatility	83.3%	82.7%	83.2%	85.2%
Risk-free interest rate	3.44%	0.95%	2.48%	0.68%
Expected life (years)	5.6	6.0	5.9	6.0