Cost cuts help Bolt Biotherapeutics (NASDAQ: BOLT) halve 2025 loss

Rhea-AI Filing Summary

Bolt Biotherapeutics reported fourth-quarter and full-year 2025 results showing sharply lower operating losses and a more focused pipeline. Full-year loss from operations narrowed to $36.1 million from $73.0 million in 2024 as research and development and general and administrative costs were reduced following restructuring.

Collaboration revenue was $7.7 million for 2025, flat with 2024, with $2.5 million recognized in the fourth quarter. Net loss improved to $33.4 million from $63.1 million a year earlier. Cash, cash equivalents and marketable securities totaled $31.8 million as of December 31, 2025, which the company expects will fund key milestones and operations into 2027.

The lead Boltbody™ ISAC candidate, BDC-4182 targeting claudin 18.2, is in a Phase 1 dose-escalation trial in gastric and gastroesophageal cancers, with initial clinical data expected in the third quarter of 2026. Two additional ISAC programs targeting CEA and PD-L1 remain on hold pending partnering or funding.

Insights

Biotech equity analyst

Bolt cut 2025 cash burn and losses while advancing its lead ISAC into Phase 1.

Bolt Biotherapeutics significantly reduced operating expenses in 2025, with research and development dropping from $57.5 million to $28.5 million and general and administrative from $18.5 million to $13.8 million. This halved loss from operations to $36.1 million, reflecting restructuring and a narrower focus.

Collaboration revenue was steady at $7.7 million for the year, suggesting ongoing partner support. Cash, cash equivalents and marketable securities of $31.8 million as of December 31, 2025 are expected to fund operations and multiple milestones into 2027, extending runway without new financing in the period covered.

On the pipeline side, BDC-4182 is already in Phase 1 dose escalation, with initial clinical data guided for the third quarter of 2026. However, CEA- and PD-L1‑targeted ISACs are paused pending partnering or funding, so actual impact will depend on securing external support and on forthcoming BDC-4182 data.

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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 12, 2026

BOLT BIOTHERAPEUTICS, INC.

(Exact name of Registrant as Specified in Its Charter)

Delaware			001-39988	47-2804636
(State or Other Jurisdiction of Incorporation)			(Commission File Number)	(IRS Employer Identification No.)
900 Chesapeake Drive
Redwood City, California				94063
(Address of Principal Executive Offices)				(Zip Code)

Registrant’s Telephone Number, Including Area Code: (650) 665-9295

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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 $0.00001 per share		BOLT		The Nasdaq Capital Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

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. ☒

Item 2.02 Results of Operations and Financial Condition.

On March 12, 2026, Bolt Biotherapeutics, Inc. (the “Company”) issued a press release announcing its financial results for the fourth quarter and full year ended December 31, 2025 and a business update. A copy of the press release is furnished herewith as Exhibit 99.1 and incorporated herein by reference.

The information contained herein and the accompanying exhibit is furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended, nor shall it be deemed incorporated by reference in any filing with the Securities and Exchange Commission made by us, whether made before or after the date hereof, regardless of any general incorporation language in such filing.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description
99.1		Press Release dated March 12, 2026.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document)

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.

			Bolt Biotherapeutics, Inc.
Date:	March 12, 2026	By:	/s/ William P. Quinn
			William P. Quinn President, Chief Executive Officer and Chief Financial Officer

Exhibit 99.1

Bolt Biotherapeutics Reports Fourth Quarter and Full-Year 2025 Financial Results and Provides Business Update

•First-in-class immune-stimulating antibody conjugate BDC-4182 in Phase 1 dose escalation study, initial clinical data expected in 3Q 2026

•Cash balance of $31.8 million as of December 31, 2025 anticipated to fund key milestones into 2027

REDWOOD CITY, CA, Mar. 12, 2026 – Bolt Biotherapeutics (Nasdaq: BOLT), a clinical-stage biopharmaceutical company developing novel immunotherapies for the treatment of cancer, today reported financial results for the fourth quarter and full-year ended December 31, 2025, and provided a business update.

“BDC‑4182 is the first of our next‑generation Boltbody™ ISACs to enter the clinic, and we saw a clear difference versus our first-gen ISACs in terms of immune response from the very first patient treated,” said Willie Quinn, President and Chief Executive Officer. “The ISAC mechanism is radically different from ADCs and T cell engagers, and we believe that demonstrating anti-tumor activity with BDC-4182 will unlock an entirely new approach to treating cancer. We continue to enroll patients with gastric and gastroesophageal cancers in the Phase 1 dose‑escalation trial and remain on track to report initial data in the third quarter of 2026.”

Recent Highlights and Anticipated Milestones

•Initial clinical data from BDC-4182 Phase 1 study for patients with gastric and gastroesophageal cancer expected in the third quarter of 2026. BDC-4182 is a next-generation BoltbodyTM ISAC targeting claudin 18.2, a clinically validated target with expression in gastric cancer, gastroesophageal junction cancer, pancreatic cancer, and other tumor types. In preclinical models, including cancer models with low claudin 18.2 expression, BDC-4182 demonstrated significant anti-tumor activity, induced immunological memory, and outperformed cytotoxic claudin 18.2 ADCs. Following a strong immune response that was observed at the initial dose levels, Bolt modified the clinical trial protocol to allow for step-up dosing, which has been successfully used commercially for T-cell engagers. The clinical trial in gastric and gastroesophageal cancers is ongoing, and the Company expects to present initial clinical data in the third quarter of 2026.

•Next-generation Boltbody™ ISACs targeting CEA and PD-L1. Bolt has two ISAC programs in preclinical development. Both programs are on hold pending partnering or funding and have the potential to be in the clinic within 18 months once activities resume.

oBolt’s CEA-targeted ISAC comprises a novel, fully human antibody with high affinity and selectivity to CEACAM5 (CEA), and not to other members of the CEACAM family, conjugated to a proprietary next-generation TLR7/8 agonist via a non-cleavable linker. Bolt’s CEA ISAC induced complete and durable anti-tumor responses in preclinical models and was more effective than a Topo1-based ADC at lower doses and in a lower antigen density tumor model. This CEA ISAC was well tolerated in a non-GLP toxicology study.

oBolt’s PD-L1 ISAC utilizes a novel human anti-PD-L1 antibody conjugated to a TLR7/8 agonist via a non-cleavable linker. This ISAC leverages a unique mechanism of action due to its ability to target both tumor and immune cells that express PD-L1. Preclinical results demonstrated that PD-L1 ISACs represent a compelling new approach to treat cancer, leveraging mechanisms that are distinct from and potentially complementary to conventional PD-1/PD-L1 blockade with the potential for enhanced immune activation and antitumor activity.

•Cash, cash equivalents, and marketable securities were $31.8 million as of December 31, 2025. Cash on hand is expected to fund multiple milestones and operations into 2027.

Fourth Quarter and Full Year 2025 Financial Results

•Collaboration Revenue – Total collaboration revenue was $2.5 million and $7.7 million for the fourth quarter and full year ended December 31, 2025, respectively, compared to zero and $7.7 million for the same quarter and year in 2024, respectively. Revenue in the fourth quarter and full year ended 2025 was due to continued progress in our collaborations as we fulfill our performance obligations to our collaboration partners. We reported no collaboration revenue in the fourth quarter of 2024 as a result of the reassessment of our expected future performance obligations.

•Research and Development (R&D) Expenses – R&D expenses were $5.0 million for the fourth quarter and $28.5 million for the full year ended December 31, 2025, respectively, compared to $11.7 million and $57.5 million for the same quarter and year in 2024, respectively. The decrease between the comparable periods was mainly due to a continued decrease in salary and related expenses primarily as a result of our restructuring plans, reduced clinical trial expenses and lower research and development expenses.

•General and Administrative (G&A) Expenses – G&A expenses were $3.1 million for the fourth quarter and $13.8 million for the full year ended December 31, 2025, respectively, compared to $3.9 million and $18.5 million for the same quarter and year in 2024, respectively. The decrease between the comparable periods was mainly due to a continued decrease in salary and related expenses primarily as a result of our restructuring plans.

•Loss from Operations – Loss from operations was $7.1 million for the fourth quarter and $36.1 million for the full year ended December 31, 2025, respectively, compared to $16.9 million and $73.0 million for the same quarter and year in 2024, respectively.

About the Boltbody™ Immune-Stimulating Antibody Conjugate (ISAC) Platform
Bolt Biotherapeutics’ Boltbody ISAC platform harnesses the precision of antibodies with the power of the innate and adaptive immune system to generate a productive anti-cancer response. Each Boltbody ISAC candidate comprises a tumor-targeting antibody, a non-cleavable linker, and a proprietary immune stimulant. The antibody is designed to target one or more markers on the surface of a tumor cell and the immune stimulant is designed to recruit and activate myeloid cells. Activated myeloid cells initiate a positive feedback loop by releasing cytokines and chemokines, chemical signals that attract other immune cells and lower the activation threshold for an immune response. This increases the population of activated immune system cells in the tumor microenvironment and promotes a robust immune response with the goal of generating durable therapeutic responses for patients with cancer.

About Bolt Biotherapeutics, Inc.

Bolt Biotherapeutics is a clinical-stage biopharmaceutical company developing novel immunotherapies for the treatment of cancer. Bolt Biotherapeutics’ pipeline reflects the Company’s expertise in myeloid biology and cancer drug development. The Company’s pipeline includes BDC-4182, a next-generation Boltbody™ Immune-Stimulating Antibody Conjugate (ISAC) clinical candidate targeting claudin 18.2. BDC-4182 is currently in a Phase 1 dose escalation trial that includes patients with gastric and gastroesophageal cancer. The Company has strategic collaborations with Genmab and Toray built around the Company’s Boltbody™ Immune-Stimulating Antibody Conjugate (ISAC) platform technology. The Company is seeking to partner BDC-3042, a Dectin-2 agonist that recently completed a first-in-human Phase 1 dose escalation trial, as well as its preclinical ISAC programs targeting CEA and PD-L1. For more information, please visit https://www.boltbio.com/.

Forward-Looking Statements

This press release contains forward-looking statements about us and our industry that involve substantial risks and uncertainties and are based on our beliefs and assumptions and on information currently available to us. All statements other than statements of historical facts contained in this press release, including statements regarding our ability to partner our CEA ISAC and PD-L1 ISAC, the advancement and success of our BDC-4182 clinical trials, the timing of initial data from our Phase 1 dose-escalation study of BDC-4182, the timing of our ISAC programs, the anti-tumor potency, safety and tolerability, and characteristics of our product candidates, the initiation of future clinical trials, the potential value of collaborations, and the expected duration of our cash runway and ability to fund key milestones into 2027, are forward-looking statements. In some cases, you can identify forward-looking statements because they contain words such as “anticipate,” “believe,” “could,” “estimate,” “expect,” “intend,” “may,” “on track,” “plan,” “potential,” “predict,” “project,” “should,” “will,” or “would,” or the negative of these words or other similar terms or expressions. Forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance, or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Forward-looking statements represent our current beliefs, estimates and assumptions only as of the date of this press release and information contained in this press release should not be relied upon as representing our estimates as of any subsequent date. These statements, and related risks, uncertainties, factors and assumptions, include, but are not limited to: the potential product candidates that we develop may not progress through clinical development or receive required regulatory approvals within expected timelines or at all; clinical trials may not confirm any safety, potency or other product characteristics described or assumed in this press release; such product candidates may not be beneficial to patients or become commercialized; and our ability to maintain our current collaborations and establish further collaborations. These risks are not exhaustive. Except as required by law, we assume no obligation to update these forward-looking statements, or to update the reasons actual results could differ materially from those anticipated in the forward-looking statements, even if new information becomes available in the future. Further information on factors that could cause actual results to differ materially from the results anticipated by our forward-looking statements is included in the reports we have filed or will file with the Securities and Exchange Commission, including our Annual Report on Form 10-K and Quarterly Reports on Form 10-Q. These filings, when available, are available on the investor relations section of our website at investors.boltbio.com and on the SEC’s website at www.sec.gov.

Investor Relations and Media Contact:

Matthew DeYoung

Argot Partners

(212) 600-1902

boltbio@argotpartners.com

BOLT BIOTHERAPEUTICS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

(in thousands, except share and per share amounts)

		For The Three Months Ended December 31,								Years Ended December 31,
		2025				2024				2025				2024
Collaboration revenue		$	2,500			$	—			$	7,695			$	7,690
Operating expenses:
Research and development			4,988				11,722				28,533				57,469
General and administrative			3,117				3,947				13,795				18,457
Restructuring charges			1,480				(222	)			1,480				3,343
Impairment charges			—				1,469				—				1,469
Total operating expense			9,585				16,916				43,808				80,738
Loss from operations			(7,085	)			(16,916	)			(36,113	)			(73,048	)
Other income (expense), net:
Interest income, net			367				980				2,496				5,255
Other income, net			87				—				241				4,675
Total other income, net			454				980				2,737				9,930
Net loss			(6,631	)			(15,936	)			(33,376	)			(63,118	)
Net unrealized (loss) gain on marketable securities			(11	)			(108	)			(118	)			60
Comprehensive loss		$	(6,642	)		$	(16,044	)		$	(33,494	)		$	(63,058	)
Net loss per share, basic and diluted		$	(3.84	)		$	(8.32	)		$	(17.85	)		$	(33.06	)
Weighted-average shares outstanding, basic and diluted			1,727,222				1,914,249				1,869,924				1,909,225

BOLT BIOTHERAPEUTICS, INC.

CONSOLIDATED BALANCE SHEETS

(In thousands)

		December 31,
		2025				2024
Assets
Current assets:
Cash and cash equivalents		$	11,703			$	7,205
Short-term investments			15,802				40,118
Restricted cash			200				784
Prepaid expenses and other current assets			2,555				2,707
Total current assets			30,260				50,814
Property and equipment, net			1,245				3,139
Operating lease right-of-use assets			19,230				21,756
Restricted cash, non-current			1,538				981
Long-term investments			4,337				22,880
Other assets			138				62
Total assets		$	56,748			$	99,632
Liabilities and stockholders' equity
Current liabilities:
Accounts payable		$	1,443			$	1,507
Accrued expenses and other current liabilities			3,717				9,083
Deferred revenue			449				3,015
Operating lease liabilities			2,826				2,251
Total current liabilities			8,435				15,856
Operating lease liabilities, net of current portion			20,132				22,958
Deferred revenue, non-current			1,544				3,620
Other long-term liabilities			132				-
Total liabilities			30,243				42,434
Commitments and contingencies
Stockholders' equity:
Common stock			—				—
Additional paid-in capital			487,305				484,504
Accumulated other comprehensive gain			(21	)			97
Accumulated deficit			(460,779	)			(427,403	)
Total stockholders' equity			26,505				57,198
Total liabilities and stockholders' equity		$	56,748			$	99,632

BOLT BIOTHERAPEUTICS, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands)

		Years Ended December 31,
		2025				2024
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss		$	(33,376	)		$	(63,118	)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization			1,291				1,781
Stock-based compensation expense			2,782				7,407
Accretion of discount on marketable securities			(670	)			(2,615	)
Gain on sale of fixed assets			(288	)			(70	)
Asset impairment			—				1,469
Non-cash lease expense			2,526				2,297
Changes in operating assets and liabilities:
Prepaid expenses and other assets			76				2,571
Accounts payable and accrued expenses			(5,430	)			(4,883	)
Operating lease liabilities, net			(2,251	)			(1,412	)
Deferred revenue			(4,642	)			(4,673	)
Other long-term liabilities			132				(43	)
Net cash used in operating activities			(39,850	)			(61,289	)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment			(72	)			(41	)
Proceeds from sales of property and equipment			963				148
Purchases of marketable securities			(29,016	)			(88,855	)
Maturities of marketable securities			72,427				146,324
Net cash provided by investing activities			44,302				57,576
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock			19				108
Net cash provided by financing activities			19				108
NET INCREASE (DECREASE) IN CASH			4,471				(3,605	)
Cash, cash equivalents and restricted cash at beginning of year			8,970				12,575
Cash, cash equivalents and restricted cash at end of period		$	13,441			$	8,970
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents		$	11,703			$	7,205
Restricted cash			1,738				1,765
Total cash, cash equivalents and restricted cash		$	13,441			$	8,970
Supplemental schedule of non-cash investing and financing activities:
Right of use assets obtained in exchange for operating lease obligations		$	—			$	6,402

FAQ

How did Bolt Biotherapeutics (BOLT) perform financially in 2025?

Bolt Biotherapeutics sharply reduced its 2025 net loss to $33.4 million, compared with $63.1 million in 2024. Loss from operations fell to $36.1 million as restructuring lowered R&D and G&A expenses, while collaboration revenue held steady at $7.7 million for the year.

What is Bolt Biotherapeutics’ cash runway after its 2025 results?

Bolt ended 2025 with $31.8 million in cash, cash equivalents, and marketable securities. The company expects this balance to fund multiple milestones and operations into 2027, providing several years of runway based on its reduced 2025 operating expense levels and collaboration revenue.

What progress did Bolt Biotherapeutics report on BDC-4182?

Bolt’s lead ISAC, BDC-4182, is in a Phase 1 dose-escalation trial for gastric and gastroesophageal cancers. The company observed strong immune responses at initial dose levels and now expects to present initial clinical data in the third quarter of 2026.

How did Bolt Biotherapeutics’ operating expenses change in 2025?

Operating expenses declined substantially in 2025. R&D expenses fell to $28.5 million from $57.5 million, and G&A expenses dropped to $13.8 million from $18.5 million. Management attributes these decreases mainly to restructuring, lower clinical trial spending, and reduced headcount-related costs.

What collaboration revenue did Bolt Biotherapeutics (BOLT) generate in 2025?

Bolt recorded $2.5 million of collaboration revenue in the fourth quarter and $7.7 million for full-year 2025, matching 2024’s annual level. The company states this revenue reflects continued progress as it fulfills performance obligations under existing collaborations with partners like Genmab and Toray.

Which Bolt Biotherapeutics pipeline programs are on hold?

Two preclinical Boltbody ISAC programs targeting CEA and PD-L1 are currently on hold. Management indicates both could enter the clinic within about 18 months once partnering or funding is secured, but further advancement depends on external support rather than internal budget alone.

Filing Exhibits & Attachments

2 documents

Press Releases

• EX-99.1 EX-99.1 363.5 KB

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA WITH EMBEDDED LINKBASES DOCUMENT 25.4 KB