Announcement • Jun 12
Caribou Biosciences, Inc. Reports Dose Escalation Durability Data For CB-011 At The 2026 European Hematology Association Annual Meeting
Caribou Biosciences, Inc. reported longer follow up data for the ongoing CaMMouflage phase 1 trial of CB-011, the Company's off-the-shelf BCMA-targeted CAR-T cell therapy, being evaluated for relapsed or refractory multiple myeloma (r/r MM). A single dose of CB-011 produced early, deep, and durable responses in a high-risk, heavily pretreated BCMA-naïve patient population. The Company also reported a case study of a patient previously treated with an approved autologous CAR-T cell therapy who achieved an early complete response after treatment with CB-011. These data are being presented during an oral presentation at the 2026 European Hematology Association (EHA) Annual Meeting, taking place June 14, 2026, at 11:00am CEST, in Stockholm, Sweden. As of the May 26, 2026, efficacy data cutoff date, 48 patients had been treated with CB-011 in the dose escalation portion of the CaMMouflage phase 1 trial. The recommended dose for expansion (RDE) is 450 million CB-011 CAR-T cells after lymphodepletion (LD) with 500 mg/m2 cyclophosphamide and 30 mg/m2 fludarabine daily for three days (selected LD regimen). Twelve BCMA-naïve patients were treated with the RDE. Median follow up for this cohort is 17.7 months. Data continue to demonstrate that CB-011 drives deep, durable responses after a single dose. Details of the efficacy results for this cohort are as follows: 92% overall response rate (ORR), 83% complete response or stringent complete response (=CR) rate, 91% minimal residual disease (MRD) negativity in 10/11 evaluable patients, 50% of patients in =CR at 15 months. As of the April 20, 2026, safety data cutoff date, CB-011 continued to show a manageable safety profile with no cases of graft-versus-host disease (GvHD), immune effector cell-associated enterocolitis, parkinsonism, or cranial nerve palsies in any patient treated with CB-011 (N=48). In all patients treated with the selected LD regimen (N=35), there was one CB-011-related death due to immune effector cell-associated hematotoxicity and three unrelated deaths due to pneumonia, respiratory syncytial virus, and respiratory acidosis, respectively. In the 12-patient BCMA-naive RDE cohort, there were no reports of grade 3 or higher (=Gr 3) immune effector cell-associated neurotoxicity syndrome (ICANS), and one (8%) =Gr 3 cytokine release syndrome (CRS). Other adverse events of special interest in the RDE cohort included three (25%) =Gr 3 infections, one (8%) =Gr 3 immune effector cell-associated HLH-like syndrome, and five (42%; 5/12) =Gr 3 prolonged cytopenias. Caribou also reported a patient case study of a 71-year-old male with r/r MM who received eight prior lines of therapy, including ciltacabtagene autoleucel, an approved autologous CAR-T cell therapy. Before entering CaMMouflage, the patient never achieved a complete response following any of his post-front-line therapies. After receiving a single dose of 450 million CB-011 CAR-T cells (the RDE), the patient achieved a CR at day 28 that was maintained at month 3 and remained ongoing as of the May 26, 2026, efficacy data cutoff date. The safety profile for this patient was manageable, with grade 1 CRS and grade 3/4 aspartate aminotransferase (AST)/alanine aminotransferase (ALT) elevation. The patient had a history of intermittent ALT elevation prior to enrolling in CaMMouflage. Translational data showed robust CB-011 CAR-T cell expansion and a rapid decrease in serum free light chains that correlated with the patient achieving a CR. 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-peptide fusion protein to blunt immune-mediated rejection. The FDA granted CB-011 RMAT, Fast Track, and Orphan Drug designations for r/r MM. 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. Thirty-five patients were treated with a single dose of CB-011 (150 million [N=6], 300 million [N=13], 450 million [N=13], and 800 million [N=3] CAR-T cells) with an LD regimen of 500 mg/m2 cyclophosphamide and 30 mg/m2 fludarabine daily for three days. The dose expansion portion of the trial is evaluating safety and efficacy of 450 million CB-011 CAR-T cells with the selected LD of 500 mg/m2 cyclophosphamide and 30 mg/m2 fludarabine daily for three days.
