Caribou Biosciences reports Q3 2026 financial results

On November 5, 2026, Caribou Biosciences, Inc., a Delaware corporation (the "Company"), issued a press release announcing the Company's financial results for the quarter ended September 30, 2026.¹ A copy of this press release is furnished as Exhibit 99.1 and is incorporated herein by reference.²

The information in Item 2.02 of this Current Report on Form 8-K (including Exhibit 99.1 attached hereto) is being furnished and shall not be deemed "filed" for purposes of Section 18 of the Securities Exchange Act of 1934³, as amended (the "Exchange Act"), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference into any filing by the Company under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language in any such filing, except as expressly set forth by specific reference in such filing.

(d) Exhibits

Exhibit No. Description

99.1 Press Release Issued by Caribou Biosciences, Inc. on November 5 , 2026⁴

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)⁴

SIGNATURES

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

Caribou Biosciences, Inc.

Date: November 5, 2026 By: /s/ Rachel E. Haurwitz

Rachel E. Haurwitz, Ph.D.

President and Chief Executive Officer

Caribou Biosciences Reports Third Quarter 2026 Financial Results

BERKELEY, Calif., November 5, 2026 (GLOBE NEWSWIRE) -- Caribou Biosciences, Inc. (Nasdaq: CRBU) today reported financial results for the third quarter of 2026.

Third quarter 2026 financial results

Licensing and other third-party revenue: Revenue from licensing and other third-party agreements was $1.6 million for the three months ended September 30, 2026, compared to $2.2 million for the same period in 2025.⁵

R&D expenses: Research and development expenses were $21.3 million for the three months ended September 30, 2026, compared to $22.4 million for the same period in 2025.⁶

G&A expenses: General and administrative expenses were $7.9 million for the three months ended September 30, 2026, compared to $9.2 million for the same period in 2025.⁷

GAAP net loss and net loss per share, basic and diluted: Caribou reported a GAAP net loss of $26.6 million, or $0.25 per share, basic and diluted, for the three months ended September 30, 2026, compared to $27.5 million, or $0.30 per share, basic and diluted.⁸

Cash, cash equivalents, and marketable securities: Caribou had $94.8 million in cash, cash equivalents, and marketable securities as of September 30, 2026, compared to $142.8 million as of December 31, 2025.⁹

October 6, 2026 announcement¹⁰

On October 6, 2026, Caribou announced that its Board of Directors had approved a restructuring of operations¹⁰ as the company conducts a process to explore strategic alternatives to maximize stockholder value, which may include, but are not limited to, a merger, acquisition, business combination, or other strategic transactions involving the company and/or its assets, including dissolution and liquidation.¹¹

Included in the restructuring is the planned discontinuation of Caribou's clinical trials and further development activities for vispa-cel and CB-011, a substantial reduction in workforce, and other cost reduction measures.¹² The Board took these actions in view of the current financing environment for allogeneic CAR-T cell therapies, which has made it increasingly challenging to secure the capital necessary to responsibly advance vispa-cel and CB-011.

Caribou has not set a timeline for the completion of the review of strategic alternatives¹³, does not intend to provide further updates unless and until the Board has approved a course of action, the review process is concluded, or disclosure is otherwise determined to be appropriate or required.

About vispacabtagene regedleucel

Vispacabtagene regedleucel (vispa-cel; formerly known as CB-010) is an allogeneic anti-CD19 CAR-T cell therapy evaluated in patients with relapsed or refractory B cell non-Hodgkin lymphoma (r/r B-NHL). To Caribou's knowledge, vispa-cel is the first allogeneic CAR-T cell therapy in the clinic with a 1

PD-1 knockout, a genome-editing strategy designed to enhance CAR-T cell activity by limiting premature CAR-T cell exhaustion. Vispa-cel is pivotal trial-ready, with FDA alignment already reached on the phase 3 clinical trial design. To Caribou's knowledge, vispa-cel is the first allogeneic CAR-T cell therapy to demonstrate safety, efficacy, and durability on par with autologous CAR-T cell therapies. The FDA granted vispa-cel Regenerative Medicine Advanced Therapy (RMAT), Fast Track, and Orphan Drug designations for B-NHL.

About CB-011

CB-011 is an allogeneic anti-BCMA CAR-T cell therapy evaluated in patients with relapsed or refractory multiple myeloma (r/r MM). To Caribou's knowledge, CB-011 is the first allogeneic CAR-T cell therapy in the clinic that is engineered to enable activity through an immune cloaking strategy with a B2M knockout and insertion of a B2M–HLA-E-peptide fusion protein to blunt immune-mediated rejection. Clinical data from the CB-011 CaMMouflage phase 1 trial has demonstrated the potential for deep, durable responses in patients with r/r MM. The FDA granted CB-011 RMAT, Fast Track, and Orphan Drug designations for r/r MM.

About Caribou Biosciences, Inc.

On October 6, 2026, Caribou Biosciences announced that it will explore strategic alternatives to maximize stockholder value, including the planned discontinuation of clinical trials and further development activities for two allogeneic CAR-T cell therapy programs, vispacabtagene regedleucel (vispa-cel) and CB-011. Prior to this announcement, Caribou was a clinical-stage CRISPR genome-editing biopharmaceutical company dedicated to developing transformative therapies for patients with devastating diseases. For more information, please visit www.cariboubio.com.

Forward-looking statements and important information

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. In some cases, you can identify forward-looking statements by terms such as "may," "will," "should," "expect," "plan," "anticipate," "could," "intend," "target," "project," "contemplate," "believe," "estimate," "predict," "potential," or "continue" or the negative of these terms or other similar expressions, although not all forward-looking statements contain these words. These forward-looking statements include, but are not limited to, any statements regarding Caribou's plans to explore opportunities to maximize stockholder value and ability to enter into any agreements or transactions in connection