RG6538

Here, we present the characterization and interim Phase I data for P-BCMA-ALLO1, a TSCM-predominant allogeneic CAR-T therapy targeting BCMA in heavily pretreated relapsed/refractory multiple myeloma...These data suggest that a TSCM cellular phenotype may offer significant advantages in efficacy, safety, and cellular persistence in the context of allogeneic CAR-T therapy. Clinical trial: NCT04960579.

P1, N=275, Recruiting, Poseida Therapeutics, Inc. | Trial completion date: Dec 2039 --> Mar 2042 | Trial primary completion date: Dec 2027 --> Mar 2029

P1, N=231, Recruiting, Poseida Therapeutics, Inc. | N=135 --> 231 | Trial completion date: Mar 2040 --> Dec 2039 | Trial primary completion date: Jun 2025 --> Dec 2027

We are currently dosing patients in arm S (Cyclophosphamide (Cy) 300 mg/m2 + Fludarabine (Flu) 30 mg/m2 X 3 days), arm P1 (Cy 500 mg/m2 + Flu 30 mg/m2 X 3 days), arm P2 (Cy 1,000 mg/m2 + Flu 30 mg/m2 X 3 days) and arm C (multiple P-BCMA-ALLO1 doses following Cy 300 mg/m2 + Flu 30 mg/m2 X 3 days). P-BCMA-ALLO1 is a non-viral transposon-generated allogeneic "off-the-shelf" CAR-T that is rapidly available for administration and well tolerated in a heavily pretreated RRMM patient population with minimal CRS/ICANS risk. Updated results including safety, preliminary efficacy, and selected biomarkers will be presented at the American Society of Hematology 2023 meeting.

Figure 1: Memory composition of P-BCMA-ALLO1 research products. P-BCMA-ALLO1 consists mostly of stem cell memory (T scm ) and central memory (T cm ) T cells that are CD62L + as opposed to effector memory (T em ) and effector (T eff ) T cells.