CYT Cyteir Therapeutics Inc

 

 

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

 

FORM 10-Q

 

(Mark One)

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

For the quarterly period ended September 30, 2023

OR

☐	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: 001-40499

 

Cyteir Therapeutics, Inc.

(Exact Name of Registrant as Specified in its Charter)

 

 

Delaware	45-5429901
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
99 Hayden Ave., Building B, Suite 450 Lexington, MA	02421
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: 857-285-4140

 

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

 

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, par value $0.001 per share		CYT		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, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

 

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 ☒

As of November 2, 2023, the registrant had 35,998,068 shares of common stock, $0.001 par value per share, outstanding.

 

 

 

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Table of Contents

 

		Page
PART I.	FINANCIAL INFORMATION	2
Item 1.	Financial Statements (Unaudited)	2
	Condensed Consolidated Balance Sheets	2
	Condensed Consolidated Statements of Operations	3
	Condensed Consolidated Statements of Stockholders’ Equity	4
	Condensed Consolidated Statements of Cash Flows	5
	Notes to Unaudited Condensed Consolidated Financial Statements	6
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	15
Item 3.	Quantitative and Qualitative Disclosures About Market Risk	23
Item 4.	Controls and Procedures	23
PART II.	OTHER INFORMATION	24
Item 1.	Legal Proceedings	24
Item 1A.	Risk Factors	24
Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	25
Item 3.	Defaults Upon Senior Securities	25
Item 4.	Mine Safety Disclosures	26
Item 5.	Other Information	26
Item 6.	Exhibits	27
Signatures		28

 

 

 

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Cautionary Note Regarding Forward-Looking Statements

This Quarterly Report on Form 10-Q contains forward-looking statements with respect to, among other things, our operations and financial performance. All statements other than statements of historical facts contained in this Quarterly Report on Form 10-Q, including statements regarding our future results of operations and financial position, business strategy and plans and our objectives for future operations, are forward-looking statements. The words “believe,” “may,” “will,” "estimate,” “continue,” “anticipate,” “intend,” “expect,” “should,” “could,” “target,” “predict,” “seek” and similar expressions are intended to identify forward-looking statements. We include forward-looking information in our discussion of the following, among other topics, the planned timing of our liquidation and dissolution, our intent to wind down our clinical trial of CYT-0851, and our estimates regarding our cash runway, expenses, and capital requirements.

These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those referenced in the section titled “Risk Factors,” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2022, filed with the U.S. Securities and Exchange Commission on March 23, 2023, which could cause actual results to differ materially. Moreover, we operate in a very competitive and rapidly changing environment and new risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in or implied by any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this Quarterly Report on Form 10-Q may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements.

The forward-looking statements included in this Quarterly Report on Form 10-Q are made only as of the date of this report. You should not rely upon forward-looking statements as predictions of future events. We cannot guarantee that the future results, levels of activity, performance or events and circumstances reflected in the forward-looking statements will be achieved or occur. Moreover, neither we nor any other person assumes responsibility for the accuracy and completeness of the forward-looking statements. We undertake no obligation to update publicly any forward-looking statements for any reason after the date of this Quarterly Report on Form 10-Q to conform these statements to actual results or reflect interim developments, except as required by law.

Some of the key factors that could cause actual results to differ include that:

• To the extent our liabilities, other obligations and expenses or claims against us are higher than we currently anticipate or larger contingency reserves are established, the amount available for distribution to our stockholders will be diminished.

• We may not be successful in selling our clinical assets and programs, which would limit the amount of cash available to distribute to our stockholders.

• The exact amount or timing of any liquidating distributions to our stockholders under our plan of liquidation and dissolution is uncertain.

• If we fail to create an adequate contingency reserve for payment of our expenses and liabilities, any stockholder receiving liquidating distributions could be held liable for payment to our creditors of their pro rata share of amounts owed to creditors in excess of the contingency reserve, up to the amount actually distributed to such stockholder in dissolution.

• Our stock transfer books will be closed at the close of business on the date we file the Certificate of Dissolution with the Delaware Secretary of State, after which it will not be possible for stockholders to publicly trade our stock.

• Our common stock may be delisted from Nasdaq and may result in limitation on future trading of our common stock prior to our liquidation and dissolution.

• We may be unable to retain employees, consultants and other resources to carry out our liquidation and dissolution.

• Our Board of Directors may abandon, modify, or delay implementation of our plan of liquidation and dissolution, even after stockholder approval.

 

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PART I—FINANCIAL INFORMATION

 

Item 1. Financial Statements.

CYTEIR THERAPEUTICS, INC.

Condensed consolidated balance sheets

(in thousands, except share and per share amounts) (unaudited)		September 30, 2023				December 31, 2022
Assets
Current assets:
Cash and cash equivalents		$	129,242			$	147,120
Prepaid expenses and other current assets			1,401				2,089
Total current assets		$	130,643			$	149,209
Property and equipment, net			105				1,699
Other assets			261				2,324
Total assets		$	131,009			$	153,232
Liabilities and stockholders’ equity
Current liabilities:
Accounts payable		$	508			$	1,128
Accrued expenses and other current liabilities			5,461				4,187
Total current liabilities		$	5,969			$	5,315
Other long term liabilities			9				1,631
Total liabilities		$	5,978			$	6,946
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $0.001 par value: 40,000,000 shares authorized    as of September 30, 2023 and December 31, 2022; no shares issued and    outstanding as of September 30, 2023 and December 31, 2022			—				—
Common stock, $0.001 par value: 280,000,000 shares    authorized as of September 30, 2023 and December 31, 2022;    36,091,075 and 35,575,694 shares issued as of September 30, 2023    and December 31, 2022, respectively; 36,083,742 and    35,516,249 shares outstanding as of September 30, 2023 and    December 31, 2022, respectively			35				35
Additional paid-in capital			287,532				284,365
Accumulated deficit			(162,536	)			(138,114	)
Total stockholders’ equity			125,031				146,286
Total liabilities and stockholders’ equity		$	131,009			$	153,232

 

See accompanying notes to condensed consolidated financial statements.

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CYTEIR THERAPEUTICS, INC.

Condensed consolidated statements of operations

		Three Months Ended September 30,								Nine Months Ended September 30,
(in thousands, except share and per share amounts) (unaudited)		2023				2022				2023				2022
Operating expenses:
Research and development		$	2,676			$	8,272			$	17,391			$	27,154
General and administrative			2,495				3,487				10,809				10,963
Total operating expenses			5,171				11,759				28,200				38,117
Loss from operations			(5,171	)			(11,759	)			(28,200	)			(38,117	)
Other income (expense):
Interest income			1,639				714				4,385				849
Loss on disposal of property and equipment			-				-				(925	)			-
Gain on lease terminations and modification			-				-				318				-
Total other income (expense)			1,639				714				3,778				849
Net loss		$	(3,532	)		$	(11,045	)		$	(24,422	)		$	(37,268	)
Net loss per share—basic and diluted		$	(0.10	)		$	(0.31	)		$	(0.68	)		$	(1.06	)
Weighted-average common stock outstanding—basic and diluted			36,030,474				35,329,137				35,647,202				35,283,454

 

See accompanying notes to condensed consolidated financial statements.

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CYTEIR THERAPEUTICS, INC.

Condensed consolidated statements of stockholders’ equity

 

	Common stock
(in thousands, except share and per share amounts) (unaudited)	Shares				Amount				Additional paid-in capital				Accumulated deficit				Total stockholders’ equity
Balance At December 31, 2021		35,219,834			$	35			$	279,310			$	(92,053	)		$	187,292
Exercise of common stock options		19,575				—				19				—				19
Vesting of early exercised options		32,605				—				39				—				39
Stock-based compensation expense		—				—				1,255				—				1,255
Net loss		—				—				—				(14,102	)			(14,102	)
Balance At March 31, 2022		35,272,014			$	35			$	280,623			$	(106,155	)		$	174,503
Exercise of common stock options		4,398				—				5				—				5
Vesting of early exercised options		26,732				—				32				—				32
Stock-based compensation expense		—				—				1,365				—				1,365
Net loss		—				—				—				(12,121	)			(12,121	)
Balance At June 30, 2022		35,303,144			$	35			$	282,025			$	(118,276	)		$	163,784
Exercise of common stock options		6,112				—				7				—				7
Vesting of early exercised options		25,511				—				30				—				30
Issuance of common stock under ESPP		19,374				—				64				—				64
Stock-based compensation expense		—				—				1,193				—				1,193
Net loss		—				—				—				(11,045	)			(11,045	)
Balance At September 30, 2022		35,354,141			$	35			$	283,319			$	(129,321	)		$	154,033

 

	Common stock
(in thousands, except share and per share amounts) (unaudited)	Shares				Amount				Additional paid-in capital				Accumulated deficit				Total stockholders’ equity
Balance At December 31, 2022		35,516,249			$	35			$	284,365			$	(138,114	)		$	146,286
Exercise of common stock options		41,588				—				42				—				42
Vesting of early exercised options		25,144				—				31				—				31
Issuance of common stock under ESPP		41,146				—				61				—				61
Stock-based compensation expense		—				—				1,042				—				1,042
Net loss		—				—				—				(12,486	)			(12,486	)
Balance At March 31, 2023		35,624,127			$	35			$	285,541			$	(150,600	)		$	134,976
Exercise of common stock options		351,879				—				428				—				428
Vesting of early exercised options		16,517				—				11				—				11
Stock-based compensation expense		—				—				776				—				776
Net loss		—				—				—				(8,404	)			(8,404	)
Balance At June 30, 2023		35,992,523			$	35			$	286,756			$	(159,004	)		$	127,787
Exercise of common stock options		64,112				—				133				—				133
Vesting of early exercised options		5,501				—				14				—				14
Issuance of common stock under ESPP		21,606				—				30				—				30
Stock-based compensation expense		—				—				599				—				599
Net loss		—				—				—				(3,532	)			(3,532	)
Balance At September 30, 2023		36,083,742			$	35			$	287,532			$	(162,536	)		$	125,031

 

See accompanying notes to condensed consolidated financial statements.

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CYTEIR THERAPEUTICS, INC.

Condensed consolidated statements of cash flows

		Nine Months Ended September 30,
(in thousands) (unaudited)		2023				2022
Cash flows from operating activities:
Net loss		$	(24,422	)		$	(37,268	)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense			368				498
Stock-based compensation			2,417				3,813
Non-cash lease expense			158				551
Loss on disposal of property and equipment			925				—
Gain on lease terminations and modification			(318	)			—
Changes in operating assets and liabilities:
Prepaid expenses and other current assets			686				(179	)
Accounts payable			(620	)			(119	)
Accrued expenses and other current liabilities			1,940				(2,912	)
Other long term liabilities			(6	)			1
Net cash used in operating activities		$	(18,872	)		$	(35,615	)
Cash flows from investing activities:
Purchases of property and equipment			—				(312	)
Proceeds from sales of property and equipment			303				—
Net cash provided by (used) in investing activities		$	303			$	(312	)
Cash flows from financing activities:
Proceeds from issuance of common stock under ESPP			92				64
Proceeds from exercise of stock options			603				31
Net cash provided by financing activities		$	695			$	95
Net decrease in cash, cash equivalents, and restricted cash			(17,874	)			(35,832	)
Cash, cash equivalents and restricted cash at beginning of period			147,377				189,979
Cash, cash equivalents and restricted cash at end of period		$	129,503			$	154,147
Supplemental disclosure of cash flows
Remeasurement of operating lease liabilities and right-of-use assets due to lease modification		$	(1,908	)			—
Vesting of early exercised options		$	56			$	101

 

The following table provides a reconciliation of the cash, cash equivalents, and restricted cash balances as of each of the dates shown below:

		Nine Months Ended September 30,
		2023				2022
Cash and cash equivalents		$	129,242			$	153,890
Restricted cash (included in other assets)			261				257
Total cash, cash equivalents, and restricted cash		$	129,503			$	154,147

 

See accompanying notes to condensed consolidated financial statements.

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CYTEIR THERAPEUTICS, INC.

Notes to condensed consolidated financial statements – (unaudited)

 

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

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our consolidated financial statements and the related notes to those statements included elsewhere in this Quarterly Report on Form 10-Q and our audited financial statements and notes thereto for the year ended December 31, 2022, included in our Annual Report on Form 10-K that was filed on March 23, 2023 with the U.S. Securities and Exchange Commission, or SEC.

In addition to historical financial information, the following discussion and analysis contains forward-looking statements that involve risks, uncertainties and assumptions. Some of the numbers included herein have been rounded for the convenience of presentation. Our actual results may differ materially from those anticipated in these forward-looking statements as a result of many factors, including those discussed under “Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2022.

Overview

On June 30, 2023, we announced the discontinuation of development of CYT-0851, our investigational monocarboxylate transporter inhibitor, and that we would initiate a plan to liquidate our assets following an orderly wind down of our operations, dissolve the Company and return remaining cash to stockholders, or the Dissolution. On September 7, 2023, our Board of Directors unanimously approved, subject to stockholder approval, the liquidation and dissolution of the Company pursuant to a plan of liquidation and dissolution, or the Plan of Dissolution, that includes the distribution of remaining cash to stockholders following an orderly wind down of our operations, including the proceeds, if any, from the sale of its assets. Prior to winding down operations, we intend to complete regulatory and patient obligations from the ongoing clinical trial. We have engaged independent advisors, who are experienced in the dissolution and liquidation of companies, to assist in our dissolution and liquidation. We have called a special meeting of our stockholders on November 16, 2023 to seek approval of the Plan of Dissolution and filed definitive proxy materials relating to the special meeting with the Securities and Exchange Commission, or the SEC, on October 12, 2023.

The Dissolution contemplates an orderly wind down of our business and operations in accordance with the provisions of Delaware General Corporation Law, or the DGCL. If our stockholders approve the Dissolution, we intend to (i) file a Certificate of Dissolution with the Delaware Secretary of State, (ii) cease all of our business activities except those relating to winding up and liquidating our business and affairs, including, but not limited to, prosecuting and defending suits by or against us, if any, and ultimately closing our Phase 1/2 clinical trial of CYT-0851, (iii) collect, sell, exchange or otherwise dispose of our remaining non-cash property and assets, (iv) pay or make a reasonable provision to pay all claims and obligations, including all contingent, conditional or un-matured contractual claims known to us, (v) make such provision as will be reasonably likely to be sufficient to provide compensation for any claim against us which is the subject of a pending action, suit or proceeding to which we are a party, (vi) make such provision as will be reasonably likely to be sufficient to provide compensation for claims that have not been made known to us or that have not arisen but that, based on facts known to us, are likely to arise or become known to us within ten years after the date of dissolution, (vii) set aside a contingency reserve consisting of cash and/or property to satisfy such claims and contingent obligations of the Company, (viii) make a distribution of remaining cash to our stockholders of record as of the date we file our Certificate of Dissolution with the Delaware Secretary of State, and (ix) take any and all other actions permitted or required by the DGCL and any other applicable laws and regulations.

Pursuant to the DGCL, our corporate existence will continue for a period of at least three years following the date on which we file our Certificate of Dissolution with the Delaware Secretary of State, for the purpose of prosecuting and defending suits, winding up the Company and making distributions to stockholders, but not for the purpose of continuing to engage in any business for which the Company was organized.

If stockholders do not approve the plan of liquidation and dissolution, then we will not distribute cash to stockholders and we will continue our corporate existence and the Board of Directors will continue to explore strategic alternatives.

CYT-0851 was being evaluated in a Phase 1/2 study as a monotherapy treatment and in combination with capecitabine or gemcitabine in advanced ovarian cancer and other solid tumors. We will continue to treat patients currently enrolled in this study until the conclusion of the study.

CYT-0851 is an investigational monocarboxylate transporter inhibitor, or MCT inhibitor, initially evaluated in a Phase 1/2 study to treat patients with hematologic malignancies and solid tumors as a monotherapy and in combination with standard of care therapies. Inhibiting MCT function in glycolytic cancer cells leads to an accumulation of intracellular lactate that impairs glycolysis and inhibits tumor cell growth, making MCTs an attractive target for cancer therapy.

In January 2023, we reported preliminary clinical activity in a small number of patients observed in the Phase 1 dose-escalation cohort with CYT-0851 in combination with capecitabine in advanced ovarian cancer. In this combination

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dose-escalation cohort, we enrolled a total of thirteen patients at dose levels of 100 mg to 400 mg of CYT-0851, which included five patients with advanced ovarian cancer. Based on the results of this study, we determined that 400 mg of CYT-0851 was the recommended Phase 2 dose in combination with capecitabine, and we expanded enrollment in the CYT-0851 and capecitabine combination cohort to enroll additional patients with advanced ovarian cancer. We discontinued enrollment in this study in connection with the announcement of the discontinuation of development of CYT-0851 in June 2023.

In January 2023, we announced the suspension of enrollment in the CYT-0851 Phase 2 monotherapy cohort due to insufficient activity observed with CYT-0851 alone. In addition to prioritizing CYT-0851 development as a potential combination therapy to treat advanced ovarian cancer at that time, we deferred all other research and development activities and reduced our headcount to 15 employees.

Since our inception in 2012, we have focused primarily on organizing and staffing our company, business planning, raising capital, establishing our intellectual property portfolio and performing research and development of novel therapeutics. We do not have any drug candidates approved for sale and have not generated any revenue from product sales. Since our inception, we have funded our operations primarily with proceeds from the sale of securities, including an aggregate of approximately $141.0 million of gross proceeds from the sale of redeemable convertible preferred stock and approximately $149.1 million of gross proceeds from the sale of common stock in our IPO, as of September 30, 2023.

We have incurred significant operating losses since inception, including net losses of $24.4 million and $37.3 million for the nine months ended September 30, 2023 and 2022, respectively. As of September 30, 2023 and December 31, 2022 we had an accumulated deficit of $162.5 million and $138.1 million, respectively. These losses have resulted primarily from costs incurred in connection with research and development activities and general and administrative costs associated with our operations. We expect to continue to generate operating losses and negative operating cash flows for the foreseeable future as we:

As of September 30, 2023, we had cash and cash equivalents of $129.2 million. We believe that our existing cash and cash equivalents as of September 30, 2023 will enable us to fund our operating expenses and capital expenditure requirements for at least twelve months from the date our condensed consolidated financial statements for the period ended September 30, 2023 are available to be issued, or until the effectiveness of our dissolution. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. See “—Liquidity and Capital Resources.”

Components of results of operations

Revenue

To date, we have not generated any revenue from product sales.

Operating expenses

Research and development expenses

Research and development expenses consist primarily of costs incurred in connection with the preclinical and clinical development and manufacture of our drug candidates, and include:

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Costs for external development activities are recognized based on an evaluation of the progress to completion of specific tasks using information provided to us by our vendors and our clinical investigative sites. Payments for these activities are based on the terms of the individual agreements, which may differ from the pattern of costs incurred, and are reflected in our consolidated financial statements as prepaid or accrued research and development expenses. Nonrefundable advance payments for goods or services to be received in the future for use in research and development activities are recorded as prepaid expenses and expensed as the related goods are delivered or the services are performed.

A significant portion of our research and development costs have been external costs, which we tracked on a program-by-program basis after a clinical drug candidate was identified. Our internal research and development costs were primarily personnel-related costs, internal lab costs and other indirect costs. The majority of our external research and development expenses to date have been incurred in connection with CYT-0851.

We do not allocate employee costs, costs associated with our discovery efforts, and facilities, including depreciation or other indirect costs, to specific programs because these costs are deployed across multiple programs and, as such, are not separately classified. We use internal resources and third-party consultants primarily to conduct our research and discovery activities as well as for managing our process development, manufacturing and clinical development activities.

We cannot reasonably estimate or know the nature, timing and estimated costs of the efforts that will be necessary to complete the liquidation and dissolution of the Company. Our level of costs may be highly variable on a quarterly basis.

 

General and administrative expenses

General and administrative expenses consist primarily of salaries and other related costs, including stock-based compensation, for personnel in our executive, finance, corporate and business development and administrative functions. General and administrative expenses also include professional fees for legal, patent, accounting, auditing, tax and consulting services, and facility-related expenses, which include direct depreciation costs and allocated expenses for rent and maintenance of facilities and other operating costs.

We expect to continue to incur general and administrative expenses in connection with our planned liquidation and dissolution of the Company.

Other income (expense)

Other income (expense) primarily consists of interest income earned on cash equivalents that generate interest on a monthly basis.

Results of operations

Comparison of the three months ended September 30, 2023 and 2022

The following table summarizes our results of operations:

		Three Months Ended September 30,
(in thousands)		2023				2022				Change
Operating expenses:
Research and development		$	2,676			$	8,272			$	(5,596	)
General and administrative			2,495				3,487				(992	)
Total operating expenses			5,171				11,759				(6,588	)
Loss from operations			(5,171	)			(11,759	)			6,588
Other income(expense):
Interest income			1,639				714				925
Total other income(expense)			1,639				714				925
Net loss		$	(3,532	)		$	(11,045	)		$	7,513

 

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Research and development expenses

The following table summarizes our research and development costs for each of the periods presented:

 

		Three Months Ended September 30,
(in thousands)		2023				2022				Change
Direct research and development expenses by program:
MCT inhibitor programs		$	1,611			$	3,122			$	(1,511	)
Unallocated research and development expenses:
Personnel expenses (including stock-based compensation)			910				3,207				(2,297	)
Other expenses			155				1,943				(1,788	)
Total research and development expenses		$	2,676			$	8,272			$	(5,596	)

 

 

Research and development expenses for the three months ended September 30, 2023 were $2.7 million, which decreased by $5.6 million from $8.3 million for the three months ended September 30, 2022. The decrease in research and development expenses was primarily attributable to the following:

General and administrative expenses

General and administrative expenses for the three months ended September 30, 2023 were $2.5 million, which decreased by $1.0 million from $3.5 million for the three months ended September 30, 2022. The decrease in general and administrative expenses was primarily attributable the following:

 

Total other income (expense)

Total other income (expense) for three months ended September 30, 2023 was $1.6 million, which increased by $0.9 million from $0.7 million for the three months ended September 30, 2022. The increase in other income (expense) was attributable to the increase in interest income due to higher interest rates on our cash equivalents, which are primarily invested in money market funds.

 

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Comparison of the nine months ended September 30, 2023 and 2022

The following table summarizes our results of operations:

		Nine Months Ended September 30,
(in thousands)		2023				2022				Change
Operating expenses:
Research and development		$	17,391			$	27,154			$	(9,763	)
General and administrative			10,809				10,963				(154	)
Total operating expenses			28,200				38,117				(9,917	)
Loss from operations			(28,200	)			(38,117	)			9,917
Other income(expense):
Interest income			4,385				849				3,536
Loss on disposal of property and equipment			(925	)			—				(925	)
Gain on lease terminations and modification			318				—				318
Total other income(expense)			3,778				849				2,929
Net loss		$	(24,422	)		$	(37,268	)		$	12,846

The following table summarizes our research and development costs for each of the periods presented:

 

		Nine Months Ended September 30,
(in thousands)		2023				2022				Change
Direct research and development expenses by program:
MCT inhibitor programs		$	8,036			$	12,699			$	(4,663	)
Unallocated research and development expenses:
Personnel expenses (including stock-based compensation)			7,624				9,311				(1,687	)
Other expenses			1,731				5,144				(3,413	)
Total research and development expenses		$	17,391			$	27,154			$	(9,763	)

 

Research and development expenses for the nine months ended September 30, 2023 were $17.4 million, which decreased by $9.8 million from $27.2 million for the nine months ended September 30, 2022. The decrease in research and development expenses was primarily attributable to the following:

General and administrative expenses

General and administrative expenses for the nine months ended September 30, 2023 were $10.8 million, which decreased by $0.2 million from $11.0 million for the nine months ended September 30, 2022. The decrease in general and administrative expenses was primarily attributable to the following:

 

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Total other income (expense)

Total other income (expense) for the nine months ended September 30, 2023 was $3.8 million, which increased by $3.0 million from $0.8 million for the nine months ended September 30, 2022. The increase in other income (expense) was attributable to the following:

Liquidity and capital resources

Sources of liquidity

Since our inception, we have not recognized any product revenue and have incurred operating losses and negative cash flows from our operations. We have not commercialized any product and we do not expect to generate revenue from sales of any products prior to our dissolution.

We have funded our operations primarily with proceeds from the sale of redeemable convertible preferred stock and the sale of our common stock in our IPO. From inception through September 30, 2023, we have raised an aggregate of approximately $141.0 million from the sale of redeemable convertible preferred stock and $136.1 million in net proceeds from the sale of our common stock with the completion of the IPO.

Funding requirements

As of September 30, 2023, our cash and cash equivalents on hand were $129.2 million. We believe that our existing cash and cash equivalents as of September 30, 2023 will be sufficient to fund our operating expenses and capital expenditure requirements for at least twelve months from the date the condensed consolidated financial statements for the period ended September 30, 2023 are available to be issued, or until the effectiveness of the Company’s dissolution. We have based this estimate on assumptions that may prove to be wrong, and we could expend our capital resources sooner than we expect.

We expect to incur expenses and operating losses for the foreseeable future as we continue to treat patients currently enrolled in our Phase 1 combination study with capecitabine or gemcitabine and as we plan and execute the liquidation and dissolution of the Company.

We are unable to estimate the exact amount of our working capital requirements. Our future capital requirements will depend on many factors, including:

20

 

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Cash flows

The following table summarizes our cash flows for each of the periods presented:

		Nine Months Ended September 30,
(in thousands)		2023				2022
Net cash used in operating activities		$	(18,872	)		$	(35,615	)
Net cash provided (used) in investing activities			303				(312	)
Net cash provided by financing activities			695				95
Net decrease in cash, cash equivalents and restricted cash		$	(17,874	)		$	(35,832	)

 

Operating activities

Net cash used in operating activities for the nine months ended September 30, 2023 was $18.9 million, compared to $35.6 million for the same period in 2022. Significant factors in the $16.7 million decrease in net cash used in operating activities include:

Investing activities

Net cash used by investing activities for the nine months ended September 30, 2023 and 2022 was immaterial due to $0.3 million purchases of property and equipment offset by proceeds of $0.3 million from the sale of property and equipment.

Financing activities

Net cash provided by financing activities for the nine months ended September 30, 2023 was $0.7 million, consisting of $0.1 million proceeds from issuance of common stock under our ESPP and $0.6 million proceeds from exercise of stock options.

Critical accounting estimates

Our management’s discussion and analysis of financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles in the United States. The preparation of our consolidated financial statements and related disclosures requires us to make judgments, estimates and assumptions that affect the reported amounts of assets and liabilities, costs and expenses and the disclosure of contingent assets and liabilities in our financial statements.

We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

There have been no significant changes to our critical accounting policies from those described in “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” included in our Annual Report on Form 10-K for the year ended December 31, 2022. If our shareholders approve the Plan of Dissolution and the likelihood is remote that the Company would return from liquidation, we would consider liquidation as imminent and implement liquidation basis of accounting.

21

 

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Emerging growth company status

We are an “emerging growth company”, or EGC, under the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. Section 107 of the JOBS Act provides that an EGC can take advantage of the extended transition period provided in Section 7(a)(2)(B) of the Securities Act of 1933, as amended, for complying with new or revised accounting standards. Thus, an EGC can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. We have elected to avail ourselves of delayed adoption of new or revised accounting standards and, therefore, we will be subject to the same requirements to adopt new or revised accounting standards as private entities.

As an EGC, we have elected to take advantage of certain exemptions and reduced reporting requirements under the JOBS Act. Subject to certain conditions, as an EGC:

We will remain an EGC until the earliest of (i) the last day of the fiscal year following the fifth anniversary of the completion of our IPO, (ii) the last day of the fiscal year in which we have total annual gross revenues of $1.235 billion or more, (iii) the date on which we have issued more than $1.0 billion in non-convertible debt during the previous rolling three-year period or (iv) the date on which we are deemed to be a large accelerated filer under the Securities Exchange Act of 1934, as amended, or the Exchange Act.

We are also a “smaller reporting company,” meaning that the market value of our stock held by non-affiliates is less than $700 million and our annual revenue was less than $100 million during the most recently completed fiscal year. We may continue to be a smaller reporting company if either (i) the market value of our stock held by non-affiliates is less than $250 million or (ii) our annual revenue was less than $100 million during the most recently completed fiscal year and the market value of our stock held by non-affiliates is less than $700 million. If we are a smaller reporting company at the time we cease to be an emerging growth company, we may continue to rely on exemptions from certain disclosure requirements that are available to smaller reporting companies. Specifically, as a smaller reporting company we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and, similar to emerging growth companies, smaller reporting companies have reduced disclosure obligations regarding executive compensation.

 

22

 

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Item 3. Quantitative and Qualitative Disclosures About Market Risk.

Interest rate risk

Our primary exposure to market risk is interest rate sensitivity, which is impacted by changes to the general level of U.S. interest rates, particularly because our cash equivalents are in the form of money market funds that are invested in U.S. Treasury securities. As of September 30, 2023 and December 31, 2022, we had cash, cash equivalents and restricted cash of $129.5 million and $149.4 million, respectively. Interest income is sensitive to changes in the general level of interest rates; however, due to the nature of these investments, an immediate 10% change in interest rates would not have a material effect on the fair market value of our investment portfolio.

As of September 30, 2023 and December 31, 2022, we had no debt outstanding, and therefore we are not subject to interest rate risk related to debt.

Foreign currency exchange risk

We are not currently exposed to significant market risk related to changes in foreign currency exchange rates.

Item 4. Controls and Procedures.

Evaluation of Disclosure Controls and Procedures

Our management, with the participation of our President and Chief Executive Officer and our Chief Financial Officer (our principal executive officer and principal financial officer, respectively), evaluated the effectiveness of our disclosure controls and procedures as of September 30, 2023. The term "disclosure controls and procedures," as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), means controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC's rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclose by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to the company's management, including its principal executive and principal financial officers, as appropriate to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on the evaluation of our disclosure controls and procedures as of September 30, 2023, our principal executive officer and principal financial officer concluded that, as of such date, our disclosure controls and procedures were effective at the reasonable assurance level.

Changes in Internal Control over Financial Reporting

No change in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) occurred during the fiscal three months ended September 30, 2023 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

 

23

 

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PART II—OTHER INFORMATION

Item 1. Legal Proceedings.

From time to time, we may become involved in litigation or other legal proceedings. We are not currently a party to any litigation or legal proceedings that, in the opinion of our management, are probable to have a material adverse effect on our business. Regardless of outcome, litigation can have an adverse impact on our business, financial condition, results of operations and prospects because of defense and settlement costs, diversion of management resources and other factors.

Item 1A. Risk Factors.

Investing in our common stock involves a high degree of risk. You should carefully consider the risks and uncertainties described in the section titled "Risk Factors" in our Annual Report on Form 10-K for the fiscal year ended December 31, 2022 together with all of the other information contained in this Quarterly Report on Form 10-Q, including the additional risk factors below and our consolidated financial statements and related notes appearing in this Quarterly Report on Form 10-Q, before deciding to invest in our common stock.

To the extent our liabilities, other obligations and expenses or claims against us are higher than we currently anticipate or larger contingency reserves are established, the amount available for distribution to our stockholders will be diminished.

As of September 30, 2023, we had $129.2 million in cash and cash equivalents. We expect to establish a reserve in connection with a Plan of Liquidation and Dissolution, or Plan of Dissolution, to be approved by our Board of Directors, which will be used to pay all expenses, including operating expenses up until the filing of the certificate of dissolution, or the Certificate of Dissolution, and other known, non-contingent liabilities, and which also includes reasonable provision for expenses of liquidation and potential, contingent and unknown liabilities as required by Delaware law. The amount of cash ultimately distributed to our stockholders in the liquidating distributions depends on the amount of our liabilities, obligations and expenses and claims against us, and contingency reserves that we establish during the liquidation process. While we will attempt to estimate reasonable reserves for such liabilities, obligations, expenses and claims against us, those estimates may be inaccurate. Factors that could impact our estimates include the following:

If any of the foregoing occurs, the amount we distribute to our stockholders may be substantially less.

We may not be successful in selling our clinical assets and programs, which would limit the amount of cash available to distribute to our stockholders.

We may sell our remaining clinical assets and programs and expect to continue pursuing the Plan of Dissolution in the near term. We may have significant expenses in connection with sale of our clinical assets and programs, which expenses will decrease the remaining cash available for use in our business and may diminish or delay any distributions to our stockholders in connection with the Plan of Dissolution.

The exact amount or timing of any liquidating distributions to our stockholders under the Plan of Dissolution is uncertain.

The precise amount and timing of any liquidating distribution to our stockholders will depend on and could be delayed by, among other things, sales of our remaining non-cash assets, any unexpected claims from third parties, including governmental authorities, and unexpected or greater than expected expenses.

Although our Board of Directors has not established a firm timetable for liquidating distributions to our stockholders, assuming our stockholders approve the Plan of Dissolution, the Board of Directors intends, subject to contingencies inherent in winding down our business, to make such liquidating distributions, if any, as promptly as practicable as creditor claims and contingent liabilities are paid or settled. However, we are currently unable to predict the precise timing of any such liquidating distributions or whether any liquidating distributions will occur at all. Additionally, a creditor could seek an

24

 

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injunction against the making of such distributions to our stockholders on the ground that the amounts to be distributed were needed to provide for the payment of our liabilities and expenses. Any action of this type could delay or substantially diminish the amount available for such distribution to our stockholders.

If we fail to create an adequate contingency reserve for payment of our expenses and liabilities, any stockholder receiving liquidating distributions could be held liable for payment to our creditors of their pro rata share of amounts owed to creditors in excess of the contingency reserve, up to the amount actually distributed to such stockholder in dissolution.

If the Plan of Dissolution is approved by our stockholders, we will file the Certificate of Dissolution with the Delaware Secretary of State dissolving Cyteir Therapeutics, Inc. Pursuant to the Delaware General Corporation Law, or the DGCL, we will continue to exist for three years after our dissolution or for such longer period as the Delaware Court of Chancery shall direct, for the purpose of prosecuting and defending suits against us and enabling us gradually to close our business, to dispose of our property, to discharge our liabilities, to conduct an orderly wind down of our clinical trial and to distribute to our stockholders any remaining assets. Under the DGCL, in the event we fail to create an adequate contingency reserve for payment of our expenses and liabilities, each stockholder of record as of the date of the filing of the Certificate of Dissolution, which is referred to hereinafter as the final record date, could be held liable for payment to our creditors of such stockholder’s pro rata share of amounts owed to creditors in excess of the contingency reserve, up to the amount actually distributed to such stockholder in dissolution.

Although the liability of any stockholder is limited to the amounts previously received by such stockholder from us pursuant to the Plan of Dissolution, this means that a stockholder could be required to return all liquidating distributions previously made to such stockholder and receive nothing from us under the Plan of Dissolution. Moreover, in the event a stockholder has paid taxes on amounts previously received, a repayment of all or a portion of such amount could result in a stockholder incurring a net tax cost if the stockholder’s repayment of an amount previously distributed does not cause a commensurate reduction in taxes payable. While we will endeavor to make adequate reserves for all known, contingent, and unknown liabilities, there is no guarantee that the reserves established by us will be adequate to cover all such expenses and liabilities.

Our stock transfer books will be closed at the close of business on the date we file the Certificate of Dissolution with the Delaware Secretary of State, after which it will not be possible for stockholders to publicly trade our stock.

On the date we file the Certificate of Dissolution with the Delaware Secretary of State, we intend to close our stock transfer books and discontinue recording transfers of our common stock. Thereafter, certificates or book entries representing our common stock will not be assignable or transferable on our books except by will, intestate succession or operation of law. The proportionate interests of all of our stockholders will be fixed on the basis of their respective stock holdings at the close of business on the final record date, and, after such date, any distributions made by us will be made solely to the stockholders of record at the close of business on the final record date, except as may be necessary to reflect subsequent transfers recorded on our books as a result of any assignments by will, intestate succession or operation of law.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds.

Use of Proceeds

On June 22, 2021, we completed our IPO pursuant to which we issued and sold 7,400,000 shares of our common stock at a public offering price of $18.00 per share. On July 1, 2021, we sold an additional 885,644 shares of our common stock at a public offering price of $18.00 per share. The offer and sale of all of our common shares were registered under the Securities Act pursuant to a registration statement on Form S-1, as amended (File No. 333-256601), which was declared effective by the SEC on June 17, 2021.

Our planned use of the net proceeds from the IPO as described in our final prospectus dated June 17, 2021 has changed due to our planned liquidation and dissolution. As a result, we currently expect to use our cash and cash equivalents, which include the net proceeds from our IPO, to conduct and orderly wind down of our business, including a wind down of our clinical trial of CYT-0851. We intend to distribute any remaining cash to our stockholders, in accordance with a Plan of Dissolution.

Item 3. Defaults Upon Senior Securities.

None.

25

 

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Item 4. Mine Safety Disclosures.

Not applicable.

Item 5. Other Information.

None.

26

 

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Item 6. Exhibits.

Exhibit Number		Description
3.1		Sixth Amended and Restated Certificate of Incorporation (incorporated by reference to Exhibit 3.1 to the Registrant's Current Report on Form 8-K (File No. 001-40499) filed with the SEC on June 25, 2021)
3.2		Second Amended and Restated Bylaws (incorporated by reference to Exhibit 3.2 to the Registrant's Current Report on Form 8-K (File No. 001-40499) filed with the SEC on June 25, 2021)
31.1*		Certification of Principal Executive Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
31.2*		Certification of Principal Financial Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002
32.1**		Certification of Principal Executive Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
32.2**		Certification of Principal Financial Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002
101.INS		Inline XBRL Instance Document – the instance document does not appear in the Interactive Data File because XBRL tags are embedded within the Inline XBRL document.
101.SCH		Inline XBRL Taxonomy Extension Schema Document
101.CAL		Inline XBRL Taxonomy Extension Calculation Linkbase Document
101.DEF		Inline XBRL Taxonomy Extension Definition Linkbase Document
101.LAB		Inline XBRL Taxonomy Extension Label Linkbase Document
101.PRE		Inline XBRL Taxonomy Extension Presentation Linkbase Document
104		Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101)

 

* Filed herewith.

** Furnished herewith.

+ Indicates management contract or compensatory plan or arrangement.

27

 

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on

its behalf by the undersigned thereunto duly authorized.

 

		Cyteir Therapeutics, Inc.
Date: November 6, 2023		By:	/s/ Markus Renschler
			Markus Renschler, M.D.
			President and Chief Executive Officer (Principal Executive Officer)
Date: November 6, 2023		By:	/s/ David Gaiero
			David Gaiero
			Chief Financial Officer and Treasurer (Principal Financial Officer)

 

28

 

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Exhibit 31.1

CERTIFICATION PURSUANT TO

RULES 13a-14(a) AND 15d-14(a) UNDER THE SECURITIES EXCHANGE ACT OF 1934,

AS ADOPTED PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Markus Renschler, M.D., certify that:

 

Date: November 6, 2023		By:	/s/ Markus Renschler
			Markus Renschler, M.D.
			President and Chief Executive Officer (Principal Executive Officer)

 

 

---

 

Exhibit 31.2

CERTIFICATION PURSUANT TO

RULES 13a-14(a) AND 15d-14(a) UNDER THE SECURITIES EXCHANGE ACT OF 1934,

AS ADOPTED PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, David Gaiero, certify that:

 

Date: November 6, 2023		By:	/s/ David Gaiero
			David Gaiero
			Chief Financial Officer and Treasurer (Principal Financial Officer)

 

 

---

 

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Cyteir Therapeutics, Inc. (the “Company”) on Form 10-Q for the period ending September 30, 2023 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that, to the best of my knowledge:

 

Date: November 6, 2023		By:	/s/ Markus Renschler
			Markus Renschler, M.D.
			President and Chief Executive Officer (Principal Executive Officer)

 

 

---

 

Exhibit 32.2

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Cyteir Therapeutics, Inc. (the “Company”) on Form 10-Q for the period ending September 30, 2023 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that, to the best of my knowledge:

 

Date: November 6, 2023		By:	/s/ David Gaiero
			David Gaiero
			Chief Financial Officer and Treasurer (Principal Financial Officer)

 

 

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v3.23.3

Document and Entity Information	9 Months Ended
	Sep. 30, 2023
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Entity Registrant Name	Cyteir Therapeutics, Inc.
Entity Central Index Key	0001662244
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Security12b Title	Common Stock, par value $0.001 per share
Trading Symbol	CYT
Security Exchange Name	NASDAQ
Entity File Number	001-40499
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	45-5429901
Entity Address Address Line One	99 Hayden Ave., Building B
Entity Address, Address Line Two	Suite 450
Entity Address City Or Town	Lexington
Entity Address State Or Province	MA
Entity Address Postal Zip Code	02421
City Area Code	857
Local Phone Number	285-4140
Document Quarterly Report	true
Document Transition Report	false

v3.23.3

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 129,242	$ 147,120
Prepaid expenses and other current assets	1,401	2,089
Total current assets	130,643	149,209
Property and equipment, net	105	1,699
Other assets	261	2,324
Total assets	131,009	153,232
Current liabilities:
Accounts payable	508	1,128
Accrued expenses and other current liabilities	5,461	4,187
Total current liabilities	5,969	5,315
Other long term liabilities	9	1,631
Total liabilities	5,978	6,946
Commitments and Contingencies (Note 10)
Stockholders' equity:
Preferred stock, $0.001 par value: 40,000,000 shares authorized as of September 30, 2023 and December 31, 2022; no shares issued and outstanding as of September 30, 2023 and December 31, 2022
Common stock, $0.001 par value: 280,000,000 shares authorized as of September 30, 2023 and December 31, 2022; 36,091,075 and 35,575,694 shares issued as of September 30, 2023 and December 31, 2022, respectively; 36,083,742 and 35,516,249 shares outstanding as of September 30, 2023 and December 31, 2022, respectively	35	35
Additional paid-in capital	287,532	284,365
Accumulated deficit	(162,536)	(138,114)
Total stockholders' equity	125,031	146,286
Total liabilities and stockholders' equity	$ 131,009	$ 153,232

v3.23.3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2023	Dec. 31, 2022
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	40,000,000	40,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	280,000,000	280,000,000
Common stock, shares issued	36,091,075	35,575,694
Common stock, shares outstanding	36,083,742	35,516,249

v3.23.3

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating expenses:
Research and development	$ 2,676	$ 8,272	$ 17,391	$ 27,154
General and administrative	2,495	3,487	10,809	10,963
Total operating expenses	5,171	11,759	28,200	38,117
Loss from operations	(5,171)	(11,759)	(28,200)	(38,117)
Other income (expense):
Interest income	1,639	714	4,385	849
Loss on disposal of property and equipment			(925)
Gain on lease terminations and modification			318
Total other income (expense)	1,639	714	3,778	849
Net loss	$ (3,532)	$ (11,045)	$ (24,422)	$ (37,268)
Net loss per share--basic	$ (0.10)	$ (0.31)	$ (0.68)	$ (1.06)
Net loss per share--diluted	$ (0.10)	$ (0.31)	$ (0.68)	$ (1.06)
Weighted-average common stock outstanding--basic	36,030,474	35,329,137	35,647,202	35,283,454
Weighted-average common stock outstanding--diluted	36,030,474	35,329,137	35,647,202	35,283,454

v3.23.3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance at Dec. 31, 2021	$ 187,292	$ 35	$ 279,310	$ (92,053)
Balance, Shares at Dec. 31, 2021		35,219,834
Exercise of common stock options	19		19
Exercise of common stock options, Shares		19,575
Vesting of early exercised options	39		39
Vesting of early exercised options, Shares		32,605
Stock-based compensation expense	1,255		1,255
Net loss	(14,102)			(14,102)
Balance at Mar. 31, 2022	174,503	$ 35	280,623	(106,155)
Balance, Shares at Mar. 31, 2022		35,272,014
Balance at Dec. 31, 2021	187,292	$ 35	279,310	(92,053)
Balance, Shares at Dec. 31, 2021		35,219,834
Net loss	(37,268)
Balance at Sep. 30, 2022	154,033	$ 35	283,319	(129,321)
Balance, Shares at Sep. 30, 2022		35,354,141
Balance at Mar. 31, 2022	174,503	$ 35	280,623	(106,155)
Balance, Shares at Mar. 31, 2022		35,272,014
Exercise of common stock options	5		5
Exercise of common stock options, Shares		4,398
Vesting of early exercised options	32		32
Vesting of early exercised options, Shares		26,732
Stock-based compensation expense	1,365		1,365
Net loss	(12,121)			(12,121)
Balance at Jun. 30, 2022	163,784	$ 35	282,025	(118,276)
Balance, Shares at Jun. 30, 2022		35,303,144
Exercise of common stock options	7		7
Exercise of common stock options, Shares		6,112
Vesting of early exercised options	30		30
Vesting of early exercised options, Shares		25,511
Issuance of common stock under ESPP	64		64
Issuance of common stock under ESPP, Shares		19,374
Stock-based compensation expense	1,193		1,193
Net loss	(11,045)			(11,045)
Balance at Sep. 30, 2022	154,033	$ 35	283,319	(129,321)
Balance, Shares at Sep. 30, 2022		35,354,141
Balance at Dec. 31, 2022	146,286	$ 35	284,365	(138,114)
Balance, Shares at Dec. 31, 2022		35,516,249
Exercise of common stock options	42		42
Exercise of common stock options, Shares		41,588
Vesting of early exercised options	31		31
Vesting of early exercised options, Shares		25,144
Issuance of common stock under ESPP	61		61
Issuance of common stock under ESPP, Shares		41,146
Stock-based compensation expense	1,042		1,042
Net loss	(12,486)			(12,486)
Balance at Mar. 31, 2023	134,976	$ 35	285,541	(150,600)
Balance, Shares at Mar. 31, 2023		35,624,127
Balance at Dec. 31, 2022	$ 146,286	$ 35	284,365	(138,114)
Balance, Shares at Dec. 31, 2022		35,516,249
Exercise of common stock options, Shares	457,579
Net loss	$ (24,422)
Balance at Sep. 30, 2023	125,031	$ 35	287,532	(162,536)
Balance, Shares at Sep. 30, 2023		36,083,742
Balance at Mar. 31, 2023	134,976	$ 35	285,541	(150,600)
Balance, Shares at Mar. 31, 2023		35,624,127
Exercise of common stock options	428		428
Exercise of common stock options, Shares		351,879
Vesting of early exercised options	11		11
Vesting of early exercised options, Shares		16,517
Stock-based compensation expense	776		776
Net loss	(8,404)			(8,404)
Balance at Jun. 30, 2023	127,787	$ 35	286,756	(159,004)
Balance, Shares at Jun. 30, 2023		35,992,523
Exercise of common stock options	133		133
Exercise of common stock options, Shares		64,112
Vesting of early exercised options	14		14
Vesting of early exercised options, Shares		5,501
Issuance of common stock under ESPP	30		30
Issuance of common stock under ESPP, Shares		21,606
Stock-based compensation expense	599		599
Net loss	(3,532)			(3,532)
Balance at Sep. 30, 2023	$ 125,031	$ 35	$ 287,532	$ (162,536)
Balance, Shares at Sep. 30, 2023		36,083,742

v3.23.3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Cash flows from operating activities:
Net loss			$ (24,422)	$ (37,268)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	$ 100	$ 200	368	498
Stock-based compensation	599	1,193	2,417	3,813
Non-cash lease expense			158	551
Loss on disposal of property and equipment			925
Gain on lease terminations and modification			(318)
Changes in operating assets and liabilities:
Prepaid expenses and other current assets			686	(179)
Accounts payable			(620)	(119)
Accrued expenses and other current liabilities			1,940	(2,912)
Other long term liabilities			(6)	1
Net cash used in operating activities			(18,872)	(35,615)
Cash flows from investing activities:
Purchases of property and equipment				(312)
Proceeds from sales of property and equipment			303
Net cash provided by (used) in investing activities			303	(312)
Cash flows from financing activities:
Proceeds from issuance of common stock under ESPP			92	64
Proceeds from exercise of stock options			603	31
Net cash provided by financing activities			695	95
Net decrease in cash, cash equivalents, and restricted cash			(17,874)	(35,832)
Cash, cash equivalents and restricted cash at beginning of period			147,377	189,979
Cash, cash equivalents and restricted cash at end of period	129,503	154,147	129,503	154,147
Supplemental disclosure of cash flows
Remeasurement of operating lease liabilities and right-of-use assets due to lease modification			(1,908)
Vesting of early exercised options			56	101
Reconciliation of cash, cash equivalents and restricted cash
Cash and cash equivalents	129,242	153,890	129,242	153,890
Restricted cash (included in other assets)	$ 261	$ 257	$ 261	$ 257
Restricted Cash and Cash Equivalents, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent	Other Assets, Noncurrent	Other Assets, Noncurrent
Total cash, cash equivalents, and restricted cash	$ 129,503	$ 154,147	$ 129,503	$ 154,147

v3.23.3

Nature of the Business	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Nature Of the Business	1. Nature of the business On June 30, 2023, Cyteir Therapeutics, Inc., (the “Company”) announced the discontinuation of development of CYT-0851, its investigational monocarboxylate transporter inhibitor, and that the Company would initiate a plan to liquidate its assets following an orderly wind down of the Company’s operations, and return remaining cash to shareholders. On September 7, 2023, the Board of Directors of the Company unanimously approved, subject to stockholder approval, the liquidation and dissolution of the Company pursuant to a plan of liquidation and dissolution (the “Plan of Dissolution”) that includes the distribution of remaining cash to stockholders following an orderly wind down of the Company’s operations, including the proceeds, if any, from the sale of its assets. Prior to winding down operations, the Company intends to complete regulatory and patient obligations from the ongoing clinical trial. The Company has engaged independent advisors, who are experienced in the dissolution and liquidation of companies, to assist in the Company’s dissolution and liquidation. The Company has called a special meeting of its stockholders on November 16, 2023 to seek approval of the Plan of Dissolution and filed definitive proxy materials relating to the special meeting with the Securities and Exchange Commission (the “SEC”) on October 12, 2023. If the Company’s stockholders approve the Plan of Dissolution and the likelihood is remote that the Company would return from liquidation, the Company would consider liquidation as imminent and implement liquidation basis of accounting. CYT-0851 was being evaluated in a Phase 1 combination study with capecitabine or gemcitabine in advanced ovarian cancer and other solid tumors. The Company will continue to treat patients currently enrolled in the Company’s Phase 1/2 study of CYT-0851 as a monotherapy and in a combination study with capecitabine or gemcitabine until the conclusion of the study. Through 2022, the Company used its expertise in DNA damage response biology and a disciplined approach to select targets for other novel, differentiated programs with the aim of building a patient-centric portfolio of effective cancer therapies. In January 2023, the Company announced a strategic prioritization that included the discontinuation of these preclinical efforts. The Company was formed as a Delaware corporation on June 4, 2012, pursuant to the General Corporation Law of the State of Delaware. The Company has a principal office in Lexington, Massachusetts. Liquidity The Company has incurred net operating losses since inception and has funded its operations primarily with proceeds from the sale of redeemable convertible preferred stock and the issuance of common stock in its initial public offering, or IPO. As of September 30, 2023, the Company had cash and cash equivalents of $129.2 million and an accumulated deficit of $162.5 million. The Company expects its operating losses and negative operating cash flows to continue into the foreseeable future. The Company expects that its cash and cash equivalents as of September 30, 2023 will be sufficient to fund its operating expenses and capital expenditure requirements for at least twelve months from the date these condensed consolidated financial statements are available to be issued, or until the effectiveness of the Company’s dissolution.

v3.23.3

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of significant accounting policies The Company's significant accounting policies are disclosed in the audited consolidated financial statements for the years ended December 31, 2022 and 2021 ("audited financial statements"), which are included in the Company's Annual Report on Form 10-K that was filed with the SEC on March 23, 2023. Since the date of the financial statements, there have been no changes to the Company's significant accounting policies, except as noted below. Interim Financial Information The accompanying condensed consolidated balance sheet at September 30, 2023, and the condensed consolidated statements of operations, statements of changes in stockholders’ equity for the three and nine months ended September 30, 2023 and 2022 and condensed consolidated statements of cash flows for the nine months ended September 30, 2023 and 2022 are unaudited. The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair presentation of the Company’s financial position at September 30, 2023 and the results of its operations for the three and nine months ended September 30, 2023 and 2022 and its cash flows for the nine months ended September 30, 2023 and 2022. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2023 and 2022 are also unaudited. The results for the three and nine months ended September 30, 2023 are not necessarily indicative of results to be expected for the full year or for any other subsequent interim period.

v3.23.3

Fair Value Measurement	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurement	3. Fair value measurement The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands):             September 30, 2023   Assets:   Total     Quoted prices in active markets for identical assets (level 1)     Significant other observable inputs (level 2)     Significant other observable inputs (level 3)   Cash equivalents:                         Money market funds   $ 128,954     $ 128,954     $ —     $ —   Total assets   $ 128,954     $ 128,954     $       $                 December 31, 2022   Assets   Total     Quoted prices in active markets for identical assets (level 1)     Significant other observable inputs (level 2)     Significant other observable inputs (level 3)   Cash equivalents:                         Money market funds   $ 146,870     $ 146,870     $ —     $ —   Total assets   $ 146,870     $ 146,870     $ —     $ —   During the nine months ended September 30, 2023 and the year ended December 31, 2022, there were no transfers between levels. The fair values of the Company’s cash equivalents, consisting of its standard checking accounts and money market funds, are based on quoted market prices in active markets without any valuation adjustment. The Company uses the carrying amounts of its restricted cash, prepaid expenses and other current assets, accounts payable and accrued expenses and other current liabilities to approximate their fair value due to the short-term nature of these amounts.

v3.23.3

Prepaid Expenses and Other Current Assets	9 Months Ended
	Sep. 30, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid Expenses and Other Current Assets	4. Prepaid expenses and other current assets Prepaid expenses and other current assets consisted of the following (in thousands):     September 30, 2023     December 31, 2022   Prepaid research and development expenses   $ 37     $ 786   Prepaid insurance     1,023       982   Prepaid other     324       304   Other receivables     17       17        Total   $ 1,401     $ 2,089

v3.23.3

Property and Equipment, Net	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	5. Property and equipment, net On January 19, 2023, the Company announced a strategic prioritization of clinical development of CYT-0851, which included the discontinuation of preclinical efforts and a workforce reduction by approximately 70% of the Company's workforce. For the nine months ended September 30, 2023, the Company recognized a loss on disposal of property and equipment totaling $0.9 million on the Company's condensed consolidated statement of operations. Property and equipment, net consisted of the following (in thousands):   Acquisition cost   Laboratory and computer equipment     Leasehold improvements     Total   As of December 31, 2022   $ 1,846     $ 1,675     $ 3,521   Disposals     (1,752 )     (1,266 )     (3,018 ) As of September 30, 2023   $ 94     $ 409     $ 503                       Accumulated depreciation and amortization   Laboratory and computer equipment     Leasehold improvements     Total   As of December 31, 2022   $ (827 )   $ (995 )   $ (1,822 ) Depreciation expense     (63 )     (305 )     (368 ) Disposals     866       926       1,792   As of September 30, 2023   $ (24 )   $ (374 )   $ (398 )                     Carrying amount   Laboratory and computer equipment     Leasehold improvements     Total   As of December 31, 2022   $ 1,019     $ 680     $ 1,699   As of September 30, 2023   $ 70     $ 35     $ 105   For the three months ended September 30, 2023 and 2022, depreciation and amortization expense related to property and equipment was $0.1 million and $0.2 million, respectively. For the nine months ended September 30, 2023 and 2022, depreciation and amortization expense related to property and equipment was $0.4 million and $0.5 million, respectively.

v3.23.3

Accrued Expenses and Other Current Liabilities	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	6. Accrued expenses and other current liabilities Accrued expenses and other current liabilities consisted of the following (in thousands):     September 30, 2023     December 31, 2022   Accrued research and development expenses   $ 1,646     $ 1,356   Accrued compensation     3,449       1,510   Accrued other     350       432   Operating lease liabilities     16       889        Total accrued expenses and other current liabilities   $ 5,461     $ 4,187

v3.23.3

Common Stock	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Common Stock	7. Common stock The voting, dividend and liquidation rights of the holders of the Company’s common stock are subject to and qualified by the rights, powers and preferences of the holders of the preferred stock as set forth in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2022. The holders of the common stock are entitled to one vote for each share of common stock held submitted to a vote of stockholders, and there are not any cumulative voting rights. Holders of common stock are entitled to receive proportionately any dividends as may be declared by the Company's board of directors subject to any preferential dividend rights of any series of preferred stock that the Company may designate and issue in the future. As of September 30, 2023 and December 31, 2022, the Company has reserved the following shares of common stock for the potential exercise of stock options:       September 30,     December 31,       2023     2022   Options to purchase common stock     2,672,831       3,460,897   Remaining shares reserved for future issuance     7,820,567       5,706,345        Total     10,493,398       9,167,242

v3.23.3

Stock-based Compensation	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	8. Stock-based compensation 2012 Stock Incentive Plan The Company adopted the 2012 Stock Incentive Plan (the “2012 Plan”) in November 2012 pursuant to which the Company can issue incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards and other stock awards. Recipients of stock options or stock appreciate rights shall be eligible to purchase shares of the Company’s common stock at an exercise price equal to the estimated fair market value of such stock on the date of grant. The exercise price may be less than fair market value if the stock award is granted pursuant to an assumption or substitution for another stock award in the event of a merger or sale of the Company. The maximum term of options granted under the 2012 Plan is ten years, and stock options typically vest over a four-year period. The Board may assign vesting terms to the stock option grants as deemed appropriate. The Company also has the right of refusal to purchase any proposed disposition of shares issued under the 2012 Plan. The 2012 Plan allows for early exercise of all stock option grants if authorized by the Board at the time of grant. The shares of common stock issued from the early exercise of stock options are restricted and vest over time. The Company has the option to repurchase any unvested shares at the original purchase price upon any voluntary or involuntary termination. At the discretion of the Board, unvested shares held by employees may accelerate vesting in the event of a change of control of the Company unless assumed or substituted by the acquirer or surviving entity. The 2012 Plan has been subsequently amended and provides for the issuance of up to 6,941,421 shares of common stock as of September 30, 2023, of which 2,732,632 shares of common stock remained available for future grant under the 2012 Plan upon the effectiveness of the 2021 Equity Incentive Plan (the “2021 Plan”) and were made available for future issuance under the 2021 Plan. 2021 Equity Incentive Plan In June 2021, the Company’s board of directors adopted and the Company’s stockholders approved the 2021 Plan, which became effective immediately prior to the effectiveness of the registration statement for the IPO. The 2021 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. Upon effectiveness of the 2021 Plan, the number of shares of common stock reserved for issuance under the 2021 Plan was 5,932,632, which represents 3,200,000 shares along with 2,732,632 shares of common stock reserved for issuance under the 2012 Plan that remained available for grant under the 2012 Plan immediately prior to the effectiveness of the 2021 Plan. Shares of the Company's common stock subject to outstanding awards granted under the 2012 Plan that expire unexercised or are terminated, surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right will become available for issuance under the 2021 Plan. Upon adoption of the 2021 Plan, the Company ceased the grant of additional awards under the 2012 Plan. The 2021 Plan includes an "evergreen" provision, which provides for an annual increase to be added on January 1st of each year beginning in 2022 and continuing through and including 2031 by the lesser of (i) 5% of the number of shares of Stock outstanding as of such date and (ii) an amount determined by the board of directors. On January 1, 2023, the number of shares of Common Stock reserved and available for issuance under the 2021 Plan increased by 1,778,784 shares. At September 30, 2023, 7,820,567 shares of common stock remained available for future grant under the 2021 Plan. 2021 Employee Stock Purchase Plan In June 2021, the Company’s board of directors adopted, and the Company’s stockholders approved, the 2021 Employee Stock Purchase Plan (the “ESPP”), which became effective immediately prior to the effectiveness of the registration statement for the IPO. The ESPP is administered by the compensation committee of the Company’s board of directors, except that the Company’s board of directors may at any time act as the administrator of the ESPP. On July 13, 2023, the Compensation Committee suspended all future purchases under the ESPP, effective as of July 14, 2023, such that no new ESPP option periods will commence after July 14, 2023. The ESPP provides participating employees with the opportunity to purchase shares of common stock, with an initial aggregate share pool of 300,000 shares of common stock. The number of shares of common stock reserved for issuance under the ESPP will automatically increase on January 1st of each year beginning in 2022 and continuing through and including 2031 by the least of (i) 1% of the number of shares of Stock outstanding as of such date, (ii) 600,000 shares of Stock and (iii) the number of shares of Stock determined by the Company’s board of directors on or prior to such date for such year, up to a maximum of 6,300,000 shares in the aggregate. On January 1, 2023, the number of shares of Common Stock reserved and available for issuance under the ESPP increased by 355,756 shares. The ESPP allows eligible employees to authorize payroll deductions of between 1% and 15% of their regular base salary or wages to be applied toward the purchase of shares of the Company's common stock on the last trading day of the offering period, subject to certain limitations contained in the ESPP. Participating employees will purchase shares of the Company's common stock at a discount of 15% on the lesser of the closing price of the Company's common stock on the Nasdaq Global Select Market (i) on the first trading day of the offering period or (ii) the last trading day of the offering period. The Company utilizes the Black Scholes option pricing model to compute the fair market value of the shares subject to outstanding options under the ESPP and compensation expense is recognized over the offering period. Participation in the ESPP is voluntary. Eligible employees become participants in the ESPP by enrolling in the plan and authorizing payroll deductions in accordance with the terms of the ESPP. At the end of each offering period, accumulated payroll deductions are used to purchase the Company’s shares at the discounted price. The Company makes no contributions to the ESPP. A participant may withdraw from the ESPP or reduce contributions to the ESPP during an offering period. If the participant elects to withdraw during an offering period, all contributions are refunded as soon as administratively practicable. If a participant elects to withdraw during an offering period, the participant may not re-enroll in the current offering but may elect to participate in future offerings, subject to the terms of the ESPP. Only whole shares of the Company may be purchased under the ESPP. The Company issued 62,754 common shares under the ESPP during the nine months ended September 30, 2023 at an average price per share of $1.45. Cash received from purchases under the ESPP for the nine months ended September 30, 2023 was $0.1 million. The Company recognized an immaterial amount of compensation expense for the ESPP during the nine months ended September 30, 2023. Early exercise of unvested stock options Shares purchased by employees pursuant to the early exercise of stock options are not deemed, for accounting purposes, to be outstanding shares until those shares vest according to their respective vesting schedules. Cash received from employee exercises of unvested options is included in long-term liabilities on the condensed consolidated balance sheets. Amounts recorded are reclassified to common stock and additional paid-in capital as the shares vest. As of September 30, 2023 and December 31, 2022, there were 7,333 and 59,445 unvested shares related to early exercises of stock options, respectively. Stock option valuation The assumptions that the Company used in the Black Scholes option-pricing model to determine the grant date fair value of stock options granted were as follows:       September 30, 2023 December 31, 2022 Risk-free interest rate range   3.64-3.65% 1.89%-4.23% Dividend yield   0.0% 0.0% Expected life of options (years)   6.0 6.0 Volatility rate range   93.0-93.3% 92.4%-93.3%   The following table summarizes the Company’s stock option activity during the nine months ended September 30, 2023:       Number of shares     Weighted average exercise price     Weighted average remaining contractual term (in years)     Aggregate intrinsic value (in thousands)   Outstanding as of December 31, 2022     3,460,897     $ 5.60       8.23     $ 375   Granted     1,054,357     $ 1.69       —       —   Exercised     (457,579 )   $ 1.32       —       —   Forfeited or cancelled     (1,384,844 )   $ 5.55       —       —   Outstanding as of September 30, 2023     2,672,831     $ 4.82       8.02     $ 1,530   Options vested and exercisable as of September 30, 2023     1,439,617     $ 6.04       7.37     $ 575     As of September 30, 2023, there was $2.9 million of unrecognized stock-based compensation expense related to the share-based compensation arrangements under the 2012 Plan. The Company expects to recognize this amount over a weighted-average period of 2.3 years. The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the common stock as of the end of the reporting period. There were no stock options granted during the three months ended September 30, 2023. The weighted-average grant date fair value of the Company’s stock options granted during the three months ended September 30, 2022 was $1.78. The total fair value of options vested during the three months ended September 30, 2023 and 2022 was $2.0 million and $1.8 million, respectively. Stock-based compensation expense Stock-based compensation expense included in the Company’s condensed consolidated statements of operations is as follows (in thousands):     Three Months Ended September 30,     Nine Months Ended September 30,     2023     2022     2023     2022   Research and development $ 183     $ 505     $ 820     $ 1,393   General and administrative   416       688       1,597       2,420        Total stock-based compensation expense $ 599     $ 1,193     $ 2,417     $ 3,813

v3.23.3

Net Loss per Share	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Net Loss Per Share	9. Net loss per share   The Company’s potentially dilutive securities have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted-average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following shares from the computation of diluted net loss per share attributable to common stockholders as of September 30, 2023 and 2022 because including them would have had an anti-dilutive effect:       Nine Months Ended September 30,       2023     2022   Options to purchase common stock     2,672,831       3,659,788   Unvested shares from early exercises     7,333       84,771

v3.23.3

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	10. Commitments and Contingencies Legal proceedings From time to time, in the ordinary course of business, the Company is subject to litigation and regulatory examinations as well as information gathering requests, inquiries and investigations. As of September 30, 2023, there were no matters which would have a material impact on the Company’s financial results.

v3.23.3

Leases	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Leases	11. Leases Operating Lease In August 2018, the Company entered into an operating lease agreement (the "Lease") for office and laboratory space within the building complex located at 128 Spring Street in Lexington, Massachusetts. The Lease commenced in November 2018, and as subsequently amended, is approximately 14,636 rentable square feet (“Original Premises”) and had a maturity date of October 31, 2023. In July 2021, the Company entered into the second amendment of the Lease and expanded the office space by approximately 5,531 square feet (the “Expansion Premises”), and extended the maturity date to December 31, 2025 for both the Original Premises and Expansion Premises. Lease payments are made monthly, subject to a 3% annual rent increase, and the Company pays for its proportionate share of building operating costs such as maintenance, utilities, and insurance that are treated as variable costs and excluded from the measurement of the Lease. On March 29, 2023, the Company entered into a Lease Amendment and Termination Agreement (the “Amendment”) with respect to the operating lease with 99 Hayden LLC, which covers certain laboratory and office space at Ledgemont Technology Center at 99 Hayden Avenue, Lexington, Massachusetts (the “Premises”). The Amendment amends the terms of the Lease to terminate the Lease as of March 31, 2023, subject to completion of the requisite surrender requirements, with respect to approximately 14,636 rentable square feet consisting of office and lab space located on two floors of the Premises, and 140 rentable square feet of storage space located on the Premises. Under the terms of the Amendment, the Company retained and consolidated into the remaining 5,531 rentable square feet of office space under the Lease at the Premises, which were to serve as the Company's principal executive office, until October 31, 2023, at which time the Lease would have terminated in its entirety. The Company recognized a gain on lease terminations and modification of $0.3 million for the nine months ended September 30, 2023 on the condensed consolidated statement of operations and derecognized $2.2 million in lease liabilities and $1.9 million in right of use assets on the condensed consolidated balance sheets. The following table summarizes the presentation of the Company's operating leases on its consolidated balance sheet:   Leases Balance sheet classification   September 30, 2023   December 31, 2022   Assets                Operating lease assets Other assets   $ —   $ 2,066   Liabilities                Current                   Operating lease liabilities Accrued expenses and other current liabilities   $ 16   $ 889      Noncurrent                   Operating lease liabilities Other long term liabilities     —     1,560    Total lease liabilities     $ 16   $ 2,449     The components of lease cost under ASC 842 included in the Company’s condensed consolidated statement of operations for the nine months ended September 30, 2023 and 2022 were as follows:         Three Months Ended September 30,     Nine Months Ended September 30,   Lease Cost Statement of operations classification   2023     2022     2023     2022   Operating lease cost Research and development   $ 11     $ 143     $ 141     $ 447   Operating lease cost General and administrative     7       44       88       124   Variable lease cost Research and development     —       100       101       344   Variable lease cost General and administrative     —       31       63       96   Total lease cost     $ 18     $ 318     $ 393     $ 1,011     The weighted average remaining lease term and weighted average discount rate of the operating leases was 0.1 years and 5.0%, respectively, at September 30, 2023. The Company made cash payments for amounts included in the measurement of operating liabilities of $0.3 million for the nine months ended September 30, 2023.   Future minimum lease payments under non-cancellable operating leases as of September 30, 2023 were as follows (in thousands): Maturity of lease liabilities   Amount   2023 (excluding the nine months ended September 30, 2023)   $ 16   Less: interest     —   Present value of operating lease liabilities   $ 16

v3.23.3

Employee benefit plans	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Employee benefit plans	12. Employee benefit plans   The Company has a 401(k) retirement plan for its employees, which is designed to be qualified under Section 401(k) of the Internal Revenue Code. Eligible employees are permitted to contribute to the 401(k) plan within statutory and 401(k) plan limits. The Company implemented a matching contribution in 2022 and has made $0.1 million matching contributions for the nine months ended September 30, 2023.

v3.23.3

Restructuring	9 Months Ended
	Sep. 30, 2023
Restructuring and Related Activities [Abstract]
Restructuring	13. Restructuring   On January 19, 2023, the Company announced a strategic prioritization of clinical development of CYT-0851, which included the discontinuation of preclinical efforts and a workforce reduction by approximately 70% of the Company's workforce. For the nine months ended September 30, 2023, the Company incurred $4.4 million of restructuring charges related to termination benefits and other related charges of which $2.5 million and $1.8 million, respectively, were recorded in research and development expenses and general and administrative expenses in the Company's condensed consolidated statements of operations. Non-cash expenses related to the strategic prioritization, consisting of an estimated $0.9 million loss on disposal of property and equipment and a gain of $0.3 million on lease terminations and modification and were recorded in other income (expense) in the Company's condensed consolidated statements of operations.   On June 30, 2023, the Company's Board of Directors announced its discontinuation of all development of CYT-0851 and intention to dissolve the Company. On September 7, 2023, our Board of Directors unanimously approved, subject to stockholder approval, the liquidation and dissolution of the Company pursuant to a plan of liquidation and dissolution. For the three months ended September 30, 2023, the Company reduced restructuring charges by $0.3 million related to termination benefits which was recorded in research and development expenses in the Company's condensed consolidated statements of operations. For the nine months ended September 30, 2023, the Company made $2.3 million of cash payments related to the restructuring. As of September 30, 2023, the restructuring accrual was approximately $2.1 million and was recorded in accrued expenses and other current liabilities in the Company's condensed consolidated balance sheet.   The following table outlines the Company's restructuring activities for the nine months ended September 30, 2023 (in thousands):   Opening Balance - December 31, 2022   $ -   Employee termination-related charges     4,370   Payments     (2,318 ) Balance - September 30, 2023   $ 2,052

v3.23.3

Subsequent Events	9 Months Ended
	Sep. 30, 2023
Subsequent Events [Abstract]
Subsequent Events	14. Subsequent events On October 3, 2023, the Company entered into the fourth amendment of the Lease and extended the term of the Lease for an additional one-month term, commencing on November 1, 2023 and expiring on November 30, 2023. Under the terms of the fourth amendment, the Company will continue to lease 5,531 square feet of office space pursuant to the Lease, which will continue to serve as the Company's principal executive office during the extended term.

v3.23.3

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2023
Accounting Policies [Abstract]
Interim Financial Information	Interim Financial Information The accompanying condensed consolidated balance sheet at September 30, 2023, and the condensed consolidated statements of operations, statements of changes in stockholders’ equity for the three and nine months ended September 30, 2023 and 2022 and condensed consolidated statements of cash flows for the nine months ended September 30, 2023 and 2022 are unaudited. The condensed consolidated interim financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments necessary for the fair presentation of the Company’s financial position at September 30, 2023 and the results of its operations for the three and nine months ended September 30, 2023 and 2022 and its cash flows for the nine months ended September 30, 2023 and 2022. The financial data and other information disclosed in these notes related to the three and nine months ended September 30, 2023 and 2022 are also unaudited. The results for the three and nine months ended September 30, 2023 are not necessarily indicative of results to be expected for the full year or for any other subsequent interim period.

v3.23.3

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis	The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands):             September 30, 2023   Assets:   Total     Quoted prices in active markets for identical assets (level 1)     Significant other observable inputs (level 2)     Significant other observable inputs (level 3)   Cash equivalents:                         Money market funds   $ 128,954     $ 128,954     $ —     $ —   Total assets   $ 128,954     $ 128,954     $       $                 December 31, 2022   Assets   Total     Quoted prices in active markets for identical assets (level 1)     Significant other observable inputs (level 2)     Significant other observable inputs (level 3)   Cash equivalents:                         Money market funds   $ 146,870     $ 146,870     $ —     $ —   Total assets   $ 146,870     $ 146,870     $ —     $ —

v3.23.3

Prepaid Expenses and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2023
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Prepaid Expenses and Other Current Assets	Prepaid expenses and other current assets consisted of the following (in thousands):     September 30, 2023     December 31, 2022   Prepaid research and development expenses   $ 37     $ 786   Prepaid insurance     1,023       982   Prepaid other     324       304   Other receivables     17       17        Total   $ 1,401     $ 2,089

v3.23.3

Property and Equipment, Net (Tables)	9 Months Ended
	Sep. 30, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment, net consisted of the following (in thousands):   Acquisition cost   Laboratory and computer equipment     Leasehold improvements     Total   As of December 31, 2022   $ 1,846     $ 1,675     $ 3,521   Disposals     (1,752 )     (1,266 )     (3,018 ) As of September 30, 2023   $ 94     $ 409     $ 503                       Accumulated depreciation and amortization   Laboratory and computer equipment     Leasehold improvements     Total   As of December 31, 2022   $ (827 )   $ (995 )   $ (1,822 ) Depreciation expense     (63 )     (305 )     (368 ) Disposals     866       926       1,792   As of September 30, 2023   $ (24 )   $ (374 )   $ (398 )                     Carrying amount   Laboratory and computer equipment     Leasehold improvements     Total   As of December 31, 2022   $ 1,019     $ 680     $ 1,699   As of September 30, 2023   $ 70     $ 35     $ 105

v3.23.3

Accrued Expenses and Other Current Liabilities (Tables)	9 Months Ended
	Sep. 30, 2023
Payables and Accruals [Abstract]
Summary of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands):     September 30, 2023     December 31, 2022   Accrued research and development expenses   $ 1,646     $ 1,356   Accrued compensation     3,449       1,510   Accrued other     350       432   Operating lease liabilities     16       889        Total accrued expenses and other current liabilities   $ 5,461     $ 4,187

v3.23.3

Common Stock (Tables)	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Schedule of Common Stock for Potential Exercise of Stock Options	As of September 30, 2023 and December 31, 2022, the Company has reserved the following shares of common stock for the potential exercise of stock options:       September 30,     December 31,       2023     2022   Options to purchase common stock     2,672,831       3,460,897   Remaining shares reserved for future issuance     7,820,567       5,706,345        Total     10,493,398       9,167,242

v3.23.3

Stock-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2023
Share-Based Payment Arrangement [Abstract]
Assumptions Used in Black Scholes Option-Pricing Model to Determine Grant Fair Value of Stock Option	The assumptions that the Company used in the Black Scholes option-pricing model to determine the grant date fair value of stock options granted were as follows:       September 30, 2023 December 31, 2022 Risk-free interest rate range   3.64-3.65% 1.89%-4.23% Dividend yield   0.0% 0.0% Expected life of options (years)   6.0 6.0 Volatility rate range   93.0-93.3% 92.4%-93.3%
Schedule of Stock Option Activity	The following table summarizes the Company’s stock option activity during the nine months ended September 30, 2023:       Number of shares     Weighted average exercise price     Weighted average remaining contractual term (in years)     Aggregate intrinsic value (in thousands)   Outstanding as of December 31, 2022     3,460,897     $ 5.60       8.23     $ 375   Granted     1,054,357     $ 1.69       —       —   Exercised     (457,579 )   $ 1.32       —       —   Forfeited or cancelled     (1,384,844 )   $ 5.55       —       —   Outstanding as of September 30, 2023     2,672,831     $ 4.82       8.02     $ 1,530   Options vested and exercisable as of September 30, 2023     1,439,617     $ 6.04       7.37     $ 575
Schedule of Stock Based Compensation Expense	Stock-based compensation expense included in the Company’s condensed consolidated statements of operations is as follows (in thousands):     Three Months Ended September 30,     Nine Months Ended September 30,     2023     2022     2023     2022   Research and development $ 183     $ 505     $ 820     $ 1,393   General and administrative   416       688       1,597       2,420        Total stock-based compensation expense $ 599     $ 1,193     $ 2,417     $ 3,813

v3.23.3

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2023
Earnings Per Share [Abstract]
Computation of Diluted Net Loss per Share Attributable to Common Stockholders	The Company excluded the following shares from the computation of diluted net loss per share attributable to common stockholders as of September 30, 2023 and 2022 because including them would have had an anti-dilutive effect:       Nine Months Ended September 30,       2023     2022   Options to purchase common stock     2,672,831       3,659,788   Unvested shares from early exercises     7,333       84,771

v3.23.3

Leases (Tables)	9 Months Ended
	Sep. 30, 2023
Leases [Abstract]
Summary of Operating Leases on Consolidated Balance Sheet	The following table summarizes the presentation of the Company's operating leases on its consolidated balance sheet:   Leases Balance sheet classification   September 30, 2023   December 31, 2022   Assets                Operating lease assets Other assets   $ —   $ 2,066   Liabilities                Current                   Operating lease liabilities Accrued expenses and other current liabilities   $ 16   $ 889      Noncurrent                   Operating lease liabilities Other long term liabilities     —     1,560    Total lease liabilities     $ 16   $ 2,449
Components of Lease Cost	The components of lease cost under ASC 842 included in the Company’s condensed consolidated statement of operations for the nine months ended September 30, 2023 and 2022 were as follows:         Three Months Ended September 30,     Nine Months Ended September 30,   Lease Cost Statement of operations classification   2023     2022     2023     2022   Operating lease cost Research and development   $ 11     $ 143     $ 141     $ 447   Operating lease cost General and administrative     7       44       88       124   Variable lease cost Research and development     —       100       101       344   Variable lease cost General and administrative     —       31       63       96   Total lease cost     $ 18     $ 318     $ 393     $ 1,011
Schedule of Future Minimum Payments Required Under Non-cancellable Operating Leases	Future minimum lease payments under non-cancellable operating leases as of September 30, 2023 were as follows (in thousands): Maturity of lease liabilities   Amount   2023 (excluding the nine months ended September 30, 2023)   $ 16   Less: interest     —   Present value of operating lease liabilities   $ 16

v3.23.3

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2023
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Activities	The following table outlines the Company's restructuring activities for the nine months ended September 30, 2023 (in thousands):   Opening Balance - December 31, 2022   $ -   Employee termination-related charges     4,370   Payments     (2,318 ) Balance - September 30, 2023   $ 2,052

v3.23.3

Nature of the Business - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Subsidiary or Equity Method Investee [Line Items]
Accumulated deficit	$ (162,536)	$ (138,114)
Cash and cash equivalents	$ 129,242	$ 147,120	$ 153,890

v3.23.3

Fair Value Measurement - Schedule of Financial Assets and Liabilities Measured at Fair Value On Recurring Basis (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets:
Total assets	$ 128,954	$ 146,870
Money Market Funds
Assets:
Cash equivalents	128,954	146,870
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets	128,954	146,870
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money Market Funds
Assets:
Cash equivalents	$ 128,954	$ 146,870

v3.23.3

Fair Value Measurement - Additional Information (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair value of assets, Level 1 to Level 2 transfers, amount	$ 0	$ 0
Fair value of assets, Level 2 to Level 1 transfers, amount	$ 0	$ 0

v3.23.3

Prepaid Expenses and Other Current Assets - Summary of Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid research and development expenses	$ 37	$ 786
Prepaid insurance	1,023	982
Prepaid other	324	304
Other receivable	17	17
Total	$ 1,401	$ 2,089

v3.23.3

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Acquisition cost, Beginning Balance	$ 3,521
Acquisition cost, Disposals	(3,018)
Acquisition cost, Ending Balance	503
Accumulated depreciation and amortization, beginning balance	(1,822)
Accumulated depreciation and amortization, Depreciation expense	(368)
Accumulated depreciation and amortization, Disposals	1,792
Accumulated depreciation and amortization, Ending balance	(398)
Property and equipment, net	105	$ 1,699
Laboratory and Computer Equipment
Property Plant And Equipment [Line Items]
Acquisition cost, Beginning Balance	1,846
Acquisition cost, Disposals	(1,752)
Acquisition cost, Ending Balance	94
Accumulated depreciation and amortization, beginning balance	(827)
Accumulated depreciation and amortization, Depreciation expense	(63)
Accumulated depreciation and amortization, Disposals	866
Accumulated depreciation and amortization, Ending balance	(24)
Property and equipment, net	70	1,019
Leasehold Improvements
Property Plant And Equipment [Line Items]
Acquisition cost, Beginning Balance	1,675
Acquisition cost, Disposals	(1,266)
Acquisition cost, Ending Balance	409
Accumulated depreciation and amortization, beginning balance	(995)
Accumulated depreciation and amortization, Depreciation expense	(305)
Accumulated depreciation and amortization, Disposals	926
Accumulated depreciation and amortization, Ending balance	(374)
Property and equipment, net	$ 35	$ 680

v3.23.3

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 19, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense		$ 100	$ 200	$ 368	$ 498
Loss on disposal of property and equipment				$ 925
Percentage of workforce reduction and preclinical efforts	70.00%

v3.23.3

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued research and development expenses	$ 1,646	$ 1,356
Accrued compensation	3,449	1,510
Accrued other	350	432
Operating lease liabilities	16	889
Total accrued expenses and other current liabilities	$ 5,461	$ 4,187

v3.23.3

Common Stock - Additional Information (Details)	9 Months Ended
	Sep. 30, 2023
Equity [Abstract]
Common stock, voting rights	The holders of the common stock are entitled to one vote for each share of common stock held submitted to a vote of stockholders, and there are not any cumulative voting rights.

v3.23.3

Common Stock - Schedule of Common Stock for Potential Exercise of Stock Options (Details) - shares	Sep. 30, 2023	Dec. 31, 2022
Class Of Stock [Line Items]
Common stock issuable upon conversion	10,493,398	9,167,242
Options to Purchase Common Stock
Class Of Stock [Line Items]
Common stock issuable upon conversion	2,672,831	3,460,897
Remaining Shares Reserved for Future Issuance
Class Of Stock [Line Items]
Common stock issuable upon conversion	7,820,567	5,706,345

v3.23.3

Stock-based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			3 Months Ended		9 Months Ended
	Jan. 01, 2023	Jun. 21, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			10,493,398		10,493,398	9,167,242
Weighted average exercise price			$ 4.82		$ 4.82	$ 5.60
Weighted-average grant date fair value of stock options granted				$ 1.78
Stock options granted			0		1,054,357
Weighted-average period					2 years 3 months 18 days
Total fair value of options vested			$ 2.0	$ 1.8
Unvested Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares related to early exercises of stock options			7,333		7,333	59,445
2012 Stock Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Maximum term of options granted					10 years
Vesting period					4 years
Common stock available for future grant			2,732,632		2,732,632
Unrecognized stock based compensation expense			$ 2.9		$ 2.9
2012 Stock Incentive Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			6,941,421		6,941,421
2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			5,932,632		5,932,632
Common stock available for future grant			7,820,567		7,820,567
Percentage of number of shares of stock outstanding		5.00%
Increase in common stock reserved and available for issuance	1,778,784
2021 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of number of shares of stock outstanding		1.00%
Proceeds from ESPP					$ 0.1
Increase in common stock reserved and available for issuance	355,756
Number of share increase					600,000
2021 Employee Stock Purchase Plan | Common Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued					62,754
Weighted average exercise price			$ 1.45		$ 1.45
2021 Employee Stock Purchase Plan | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock		300,000
Number of shares of stock authorized			6,300,000		6,300,000
Current Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			3,200,000		3,200,000
2012 Shares Made Available 2021 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Issuance of shares of common stock			2,732,632		2,732,632

v3.23.3

Stock-based Compensation - Assumptions Used in Black Scholes Option-Pricing Model to Determine Grant Fair Value of Stock Option (Details) - Stock Option	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate range, minimum	3.64%	1.89%
Risk-free interest rate range, maximum	3.65%	4.23%
Dividend yield	0.00%	0.00%
Expected life of options (years)	6 years	6 years
Volatility rate range, minimum	93.00%	92.40%
Volatility rate range, maximum	93.30%	93.30%

v3.23.3

Stock-based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Number of shares, beginning balance		3,460,897
Number of shares, Granted	0	1,054,357
Number of shares, Exercised		(457,579)
Number of shares, Forfeited or cancelled		(1,384,844)
Number of shares, ending balance	2,672,831	2,672,831	3,460,897
Number of shares, Options vested and exercisable	1,439,617	1,439,617
Weighted average exercise price, beginning balance		$ 5.60
Weighted average exercise price, Granted		1.69
Weighted average exercise price, Exercised		1.32
Weighted average exercise price, Forfeited or cancelled		5.55
Weighted average exercise price, ending balance	$ 4.82	4.82	$ 5.60
Weighted average exercise price, Options vested and exercisable	$ 6.04	$ 6.04
Weighted average remaining contractual term (in years), balance		8 years 7 days	8 years 2 months 23 days
Weighted average remaining contractual term (in years), Options vested and exercisable		7 years 4 months 13 days
Aggregate intrinsic value, beginning balance		$ 375
Aggregate intrinsic value, ending balance	$ 1,530	1,530	$ 375
Aggregate intrinsic value, Options vested and exercisable	$ 575	$ 575

v3.23.3

Stock-based Compensation - Schedule of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 599	$ 1,193	$ 2,417	$ 3,813
Research and Development
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	183	505	820	1,393
General and Administrative
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total stock-based compensation expense	$ 416	$ 688	$ 1,597	$ 2,420

v3.23.3

Net Loss per Share - Computation of Diluted Net Loss per Share Attributable to Common Stockholders (Details) - shares	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of EPS	2,672,831	3,659,788
Unvested Shares from Early Exercises
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of EPS	7,333	84,771

v3.23.3

Leases - Additional Information (Details) $ in Thousands	1 Months Ended		9 Months Ended
	Jul. 31, 2021 ft²	Aug. 31, 2018 ft²	Sep. 30, 2023 USD ($)	Mar. 29, 2023 ft² Floor
Lessee, Lease, Description [Line Items]
Operating lease, weighted average remaining lease term			1 month 6 days
Operating lease, weighted average discount rate			5.00%
Operating lease, payments | $			$ 300
Operating Lease Liability Derecognized | $			2,200
Right of Use Assets Derecognized | $			1,900
Gain on lease terminations and modification | $			$ 318
Massachusetts
Lessee, Lease, Description [Line Items]
Total rentable area				5,531
Premises | Massachusetts
Lessee, Lease, Description [Line Items]
Total rentable area		14,636
Lease expiration date		Oct. 31, 2023
Number of square feet expanding	5,531
Operating lease extended maturity date	Dec. 31, 2025
Description of option to extend operating lease			In July 2021, the Company entered into the second amendment of the Lease and expanded the office space by approximately 5,531 square feet (the “Expansion Premises”), and extended the maturity date to December 31, 2025 for both the Original Premises and Expansion Premises.
Existence option to extend operating lease	true
Increase in annual rent percentage	3.00%
Office and Lab Space [Member] | Massachusetts
Lessee, Lease, Description [Line Items]
Total rentable area				14,636
Number of floors | Floor				2
Storage Space [Member] | Massachusetts
Lessee, Lease, Description [Line Items]
Total rentable area				140

v3.23.3

Leases - Summary of Operating Leases on Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets
Operating lease assets		$ 2,066
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Liabilities
Operating lease liabilities, Current	$ 16	$ 889
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Other Accrued Liabilities, Current	Accounts Payable and Other Accrued Liabilities, Current
Operating lease liabilities, Noncurrent		$ 1,560
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Total lease liabilities	$ 16	$ 2,449

v3.23.3

Leases - Components of Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Lessee, Lease, Description [Line Items]
Total lease cost	$ 18	$ 318	$ 393	$ 1,011
Research and Development
Lessee, Lease, Description [Line Items]
Operating lease cost	11	143	141	447
Variable lease cost		100	101	344
General and Administrative
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 7	44	88	124
Variable lease cost		$ 31	$ 63	$ 96

v3.23.3

Leases - Schedule of Future Minimum Payments Required Under Non-cancellable Operating Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Lessee, Operating Lease, Liability, to be Paid [Abstract]
2023 (excluding the nine months ended September 30, 2023)	$ 16
Present value of operating lease liabilities	$ 16	$ 2,449

v3.23.3

Employee benefit plans - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Share-Based Payment Arrangement [Abstract]
Contributions by employer	$ 0.1

v3.23.3

Restructuring - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Jan. 19, 2023	Sep. 30, 2023	Sep. 30, 2023
Restructuring Cost and Reserve [Line Items]
Percentage of Workforce Reduction and Preclinical Efforts	70.00%
Restructuring charges			$ 4,400
Cash payments related to restructuring			2,318
Loss on disposal of property and equipment			925
Gain on lease terminations and modification			318
Restructuring accrual			2,100
Research and development
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 300	2,500
General and Administrative
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 1,800

v3.23.3

Restructuring - Schedule of Restructuring Activities (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2023 USD ($)
Restructuring and Related Activities [Abstract]
Opening Balance - December 31, 2022	$ 0
Employee termination related charges	4,370
Payments	(2,318)
Balance - September 30, 2023	$ 2,052

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