On March 31, 2026 Caribou Biosciences, Inc. (Nasdaq: CRBU), a leading clinical-stage CRISPR genome-editing biopharmaceutical company, reported that the U.S. Food and Drug Administration (FDA) has granted Regenerative Medicine Advanced Therapy (RMAT) designation to CB-011 for relapsed or refractory multiple myeloma (r/r MM). CB-011, an allogeneic anti-BCMA CAR-T cell therapy, is being evaluated in the company’s ongoing open-label, multicenter CaMMouflage phase 1 clinical trial evaluating patients with r/r MM.
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"Only one in 10 people with multiple myeloma in the U.S. are able to receive CAR-T cell therapies due to long wait times and manufacturing limitations," said Adriana Rossi, MD, director of CAR-T and stem cell transplant clinical program at the center of excellence for multiple myeloma at Mount Sinai and an investigator on the CaMMouflage trial. "This highlights a critical gap in access for patients with relapsed or refractory disease. An off-the-shelf CAR-T cell therapy like CB-011 could help bridge that gap by offering a readily available treatment option to a broader group of patients."
As previously reported in November 2025, 48 patients have been treated in the dose escalation portion of the company’s CaMMouflage phase 1 clinical trial. The 450×106 CAR-T cell dose was selected as the recommended dose for expansion (RDE). In dose escalation, 12 BCMA-naïve patients were treated with the RDE; efficacy outcomes from this cohort included a 92% (11/12) overall response rate (ORR), 75% (9/12) ≥ complete response (CR) rate, and 91% (10/11 evaluable) minimal residual disease (MRD) negativity as of a September 24, 2025, data cutoff. CB-011 has demonstrated a manageable safety profile, with no cases of graft-versus-host disease, immune effector cell-associated enterocolitis, parkinsonism, or cranial nerve palsies observed at any dose level. Treatment emergent adverse events (TEAEs) in ≥25% of all patients treated with CB-011 following the selected lymphodepletion (LD) regimen (N=35) were as follows: neutropenia (80%), anemia (60%), thrombocytopenia (49%), infections (49%), dizziness (31%), cytokine release syndrome (31%), fatigue (31%), leukopenia (29%), decreased appetite (29%), constipation (26%), and pyrexia (26%) as of the data cutoff date.
"The FDA’s RMAT designation for CB-011 recognizes both the significant unmet need in multiple myeloma and the encouraging clinical data we have seen so far in the CaMMouflage trial," said Tina Albertson, MD, PhD, chief medical officer at Caribou Biosciences. "The dose escalation data highlight the potential of CB-011 as the best-in-class allogeneic CAR-T cell therapy for relapsed or refractory multiple myeloma. We look forward to initiating discussion with the FDA regarding future clinical development of CB-011 and to reporting additional data this year as we continue to enroll both BCMA-naïve and BCMA-exposed patients in dose expansion."
RMAT designation is a dedicated program designed to expedite the development and review processes for promising therapeutic candidates intended to address an unmet medical need in patients with serious conditions. This designation provides important benefits in the drug development process and is designed to facilitate and expedite development and regulatory review, including providing eligibility for priority and rolling reviews and accelerated approval, if relevant criteria are satisfied.
About CB-011
CB-011 is an allogeneic anti-BCMA CAR-T cell therapy being 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 fusion protein to blunt immune-mediated rejection. The FDA granted CB-011 Regenerative Medicine Advanced Therapy (RMAT), Fast Track, and Orphan Drug designations for r/r MM.
About the CaMMouflage phase 1 clinical trial
The CaMMouflage clinical trial is a multicenter, open-label phase 1 trial evaluating CB-011 in adults with r/r MM who have been treated with three or more prior lines of therapy. Using a 3+3 dose escalation design, safety and efficacy of CB-011 were evaluated in 48 patients at multiple dose levels and two different lymphodepletion (LD) regimens. Thirteen patients were treated with a single dose of CB-011 (50×106 [N=3], 150×106 [N=7], and 450×106 [N=3] CAR-T cells) with an LD regimen of 300 mg/m2 cyclophosphamide and 30 mg/m2 fludarabine daily for three days, and 35 patients were treated with a single dose of CB-011 (150×106 [N=6], 300×106 [N=13], 450×106 [N=13], and 800×106 [N=3] CAR-T cells) with an LD regimen of 500 mg/m2 cyclophosphamide and 30 mg/m2 fludarabine daily for three days. The ongoing dose expansion portion of the trial will evaluate safety and efficacy of CB-011 at 450×106 CAR-T cells with the selected LD of 500 mg/m2 cyclophosphamide and 30 mg/m2 fludarabine daily for three days. Additional information on the CaMMouflage trial (NCT05722418) can be found at www.clinicaltrials.gov.
(Press release, Caribou Biosciences, MAR 31, 2026, View Source [SID1234664078])