8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

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FORM 8-K

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CURRENT REPORT

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

Date of Report (Date of earliest event reported): November 21, 2022

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Caribou Biosciences, Inc.

(Exact name of Registrant as Specified in Its Charter)

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Delaware	001-40631	45-3728228
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)
2929 7th Street, Suite 105 Berkeley, California		94710
(Address of Principal Executive Offices)		(Zip Code)

Registrant’s Telephone Number, Including Area Code: (510) 982-6030

N/A

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

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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:

☐	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, $0.0001 par value per share	CRBU	NASDAQ Global Select 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 7.01 Regulation FD Disclosure.

On November 21, 2022, Caribou Biosciences, Inc. (the "Company") issued a press release announcing that it has received clearance of its investigational new drug (“IND”) application from the U.S. Food and Drug Administration (“FDA”) for CB-011, a genome-edited allogeneic anti-BCMA CAR-T cell therapy with immune cloaking. A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K and also is incorporated by reference into this Item 7.01.

The information contained in this Item 7.01 and in the accompanying Exhibit 99.1 shall not be deemed filed for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing or other document under the Exchange Act or the Securities Act of 1933, as amended (the “Securities Act”), regardless of any general incorporation language in any such filing or document, except as shall be expressly set forth by specific reference in any such filing or document.

Item 8.01 Other Events.

On November 21, 2022, the Company announced that it has received clearance of its IND application from the FDA for CB-011, a genome-edited allogeneic anti-BCMA CAR-T cell therapy with immune cloaking. The safety and efficacy of a single dose of CB-011 in adult patients with relapsed or refractory multiple myeloma (“r/r MM”) will be evaluated in the multicenter, open-label CaMMouflage phase 1 clinical trial.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.	Description
99.1	Press Release Issued by Caribou Biosciences, Inc. on November 21, 2022
104	Cover Page Interactive Data File (embedded within the Inline XBRL document)

SIGNATURES

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

			Caribou Biosciences, Inc.
Date:	November 21, 2022	By:	/s/ Rachel E. Haurwitz
			Rachel E. Haurwitz President and Chief Executive Officer

EX-99.1

Exhibit 99.1

Caribou Biosciences Announces FDA Clearance of IND Application for CB-011, an Allogeneic Anti-BCMA CAR-T Cell Therapy for the Treatment of Relapsed or Refractory Multiple Myeloma

-- CaMMouflage Phase 1 clinical trial to initiate patient enrollment at dose level 1 in early 2023 --

-- CB-011 is engineered with a differentiated immune cloaking strategy, designed to enhance persistence --

-- CB-011 is Caribou’s second off-the-shelf CAR-T cell therapy to enter the clinic --

BERKELEY, CA, November 21, 2022– Caribou Biosciences, Inc. (Nasdaq: CRBU), a leading clinical-stage CRISPR genome-editing biopharmaceutical company, today announced that it has received clearance of its Investigational New Drug (IND) application from the U.S. Food and Drug Administration (FDA) for CB-011, a genome-edited allogeneic anti-BCMA CAR-T cell therapy with immune cloaking. The CaMMouflage Phase 1 clinical trial, a multicenter, open-label study to evaluate the safety and efficacy of a single dose of CB-011 in adult patients with relapsed or refractory multiple myeloma (r/r MM), is expected to initiate patient enrollment for treatment at dose level 1 (50x106 CAR-T cells) in early 2023.

“Clearance of our second IND application represents another key milestone for our pipeline of promising allogeneic cell therapies designed to have enhanced persistence of antitumor activity,” said Rachel Haurwitz, Ph.D., Caribou’s president and chief executive officer. “CB-011 is designed with an immune cloaking strategy to reduce rejection of the cell therapy by a patient’s T and NK cells and we use Caribou’s highly precise and specific Cas12a chRDNA genome-editing technology to manufacture this product candidate. We are excited to develop CB-011 as an off-the-shelf cell therapy that may reach a broader number of patients with multiple myeloma than are currently being served, and we look forward to initiating patient enrollment in the CaMMouflage trial in early 2023.”

CB-011 is the second allogeneic cell therapy advancing into clinical development from Caribou’s CAR-T cell platform targeting hematologic malignancies. Caribou’s first allogeneic cell therapy, CB-010, an allogeneic anti-CD19 CAR-T cell therapy with a PD-1 knockout, is being evaluated in the ongoing ANTLER Phase 1 clinical trial in patients with relapsed or refractory B cell non-Hodgkin lymphoma (r/r B-NHL). Encouraging safety and antitumor activity for CB-010 at dose level 1 have been reported from the ANTLER trial.

“CAR-T cell therapies have shown great promise for treating patients with relapsed or refractory multiple myeloma,” said Sundar Jagannath, M.D., director of the Multiple Myeloma Center of Excellence at Tisch Cancer Institute, Mount Sinai Hospital, New York. “Allogeneic, or ‘off-the-shelf,’ CAR-T cell therapies would provide a great option for patients with multiple myeloma, helping to overcome the need for bridging therapies as well as variable quality and manufacturing timelines of autologous CAR-T cells.”

CB-011 is the first allogeneic anti-BCMA CAR-T cell therapy, to Caribou’s knowledge, that is engineered to improve persistence of antitumor response through an immune cloaking genome-

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editing approach that removes the B2M protein and inserts a B2M–HLA-E fusion protein. CB-011 has four edits implemented via Caribou’s Cas12a CRISPR hybrid RNA-DNA (chRDNA) technology:

•Edits 1 and 2 – A humanized anti-BCMA CAR is site-specifically inserted into the TRAC gene to target cancer cells, thereby knocking out expression of the T cell receptor to reduce the risk of graft versus host disease (GvHD).

•Edits 3 and 4 – A B2M–HLA-E peptide fusion gene is site-specifically inserted into the B2M gene of the CAR-T cells to prevent recognition and rejection by patient T cells and blunt rejection by NK cells. These edits knock out endogenous B2M expression, eliminating endogenous HLA class I presentation and reducing T cell-mediated rejection, while enabling expression of B2M–HLA-E needed to inhibit NK cell-mediated rejection.

About the CaMMouflage Trial

The CaMMouflage Phase 1 trial is an open-label, multicenter clinical trial designed to evaluate CB-011 in adults with relapsed or refractory multiple myeloma (r/r MM). Part A, a 3+3 dose escalation design, will evaluate the safety and tolerability of CB-011 at multiple dose levels and will be utilized to determine the maximum tolerated dose and/or the recommended Phase 2 dose. Part B is the dose expansion portion with the primary objective of determining tumor response after a single dose of CB-011. CaMMouflage will include patients who have had 3 or more prior lines of therapy and will exclude patients who have received a BCMA-targeted therapy within the last 3 months and/or any prior CAR-T cell therapy.

Caribou plans to initiate patient enrollment in the CaMMouflage trial to treat patients with a single administration of CB-011 at dose level 1 (50x106 CAR-T cells) in early 2023.

About Multiple Myeloma

Multiple myeloma (MM) is the second most common hematologic malignancy in the United States. According to the National Cancer Institute, an estimated 160,000 people in 2019 were living with MM and an estimated 34,000 individuals are diagnosed with MM each year in the United States. Approximately 50% of patients with MM relapse and have their cancer return after first line treatment or are refractory and do not respond to current treatments.

About Caribou’s Novel Next-Generation CRISPR Platform

CRISPR genome editing uses easily designed, modular biological tools to make DNA changes in living cells. There are two basic components of Class 2 CRISPR systems: the nuclease protein that cuts DNA and the RNA molecule(s) that guide the nuclease to generate a site-specific, double-stranded break, leading to an edit at the targeted genomic site. CRISPR systems are capable of editing unintended genomic sites, known as off-target editing, which may lead to harmful effects on cellular function and phenotype. In response to this challenge, Caribou has developed CRISPR hybrid RNA-DNA guides (chRDNAs; pronounced “chardonnays”) that direct substantially more precise genome editing compared to all-RNA guides. Caribou is deploying the power of its Cas12a chRDNA technology to carry out multiple edits at high efficiency, including multiplex gene insertions, to develop CRISPR-edited therapies.

About Caribou Biosciences, Inc.

Caribou Biosciences is a clinical-stage CRISPR genome-editing biopharmaceutical company dedicated to developing transformative therapies for patients with devastating diseases. The company’s genome-editing platform, including its proprietary Cas12a chRDNA technology, enables superior

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precision to develop cell therapies that are specifically engineered for enhanced persistence. Caribou is advancing a pipeline of off-the-shelf CAR-T and CAR-NK cell therapies for the treatment of patients with hematologic malignancies and solid tumors.

For more information about Caribou, visit www.cariboubio.com and follow the company @CaribouBio.

“Caribou Biosciences” and the Caribou logo are registered trademarks of Caribou Biosciences, Inc.

Forward-Looking Statements

This press release contains forward-looking statements, within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, without limitation, statements related to Caribou’s strategy, plans, and objectives, and expectations regarding its clinical and preclinical development programs, including the timing of the initiation of its CaMMouflage Phase 1 trial for CB-011, the expected timing of patient enrollment for the trial, as well as the results and duration of the trial and expectations and timing regarding the release of clinical data from Caribou’s ongoing ANTLER Phase 1 clinical trial for its CB-010 product candidate. Management believes that these forward-looking statements are reasonable as and when made. However, such forward-looking statements are subject to risks and uncertainties, and actual results may differ materially from any future results expressed or implied by the forward-looking statements. Risks and uncertainties include, without limitation, risks inherent in development of cell therapy products; uncertainties related to the initiation, cost, timing, progress, and results of current and future research and development programs, preclinical studies, and clinical trials; and the risk that initial or interim clinical trial data will not ultimately be predictive of the safety and efficacy of Caribou’s product candidates or that clinical outcomes may differ as more patient data becomes available; as well as other risk factors described from time to time in Caribou’s filings with the Securities and Exchange Commission, including its Annual Report on Form 10-K for the year ended December 31, 2021 and subsequent filings. In light of the significant uncertainties in these forward-looking statements, you should not rely upon forward-looking statements as predictions of future events. Except as required by law, Caribou undertakes no obligation to update publicly any forward-looking statements for any reason.

Caribou Biosciences, Inc. Contacts:

Investors:

Amy Figueroa, CFA

afigueroa@cariboubio.com

Media:

Peggy Vorwald, Ph.D.

pvorwald@cariboubio.com

Investors and Media:

Elizabeth Wolffe, Ph.D., and Sylvia Wheeler

Wheelhouse LSA

lwolffe@wheelhouselsa.com

swheeler@wheelhouselsa.com

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Photos accompanying this announcement are available at

https://pr.globenewswire.com/FileDownloader/DownloadFile?source=pnr&fileGuid=5f227084-9845-4932-b673-81588114f336

https://pr.globenewswire.com/FileDownloader/DownloadFile?source=pnr&fileGuid=8feb244c-bec0-4181-a28e-216830a3e3b4

CB-011

CB-011 is a genome-edited allogeneic anti-BCMA CAR-T cell therapy with immune cloaking.

CB-011 Immune Cloaking

CB-011 is engineered to improve persistence of antitumor response through an immune cloaking genome-editing approach that removes the B2M protein and inserts a B2M–HLA-E fusion protein.

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XML

Cover	Nov. 21, 2022
Cover [Abstract]
Document Type	8-K
Document Period End Date	Nov. 21, 2022
Entity Registrant Name	Caribou Biosciences, Inc.
Entity Incorporation, Date of Incorporation	DE
Entity File Number	001-40631
Entity Tax Identification Number	45-3728228
Entity Address, Address Line One	2929 7th Street
Entity Address, Address Line Two	Suite 105
Entity Address, City or Town	Berkeley
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94710
City Area Code	510
Local Phone Number	982-6030
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Title of 12(b) Security	Common Stock, $0.0001 par value per share
Trading Symbol	CRBU
Security Exchange Name	NASDAQ
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Amendment Flag	false
Entity Central Index Key	0001619856