Adicet Bio (Nasdaq: ACET) reported that its allogeneic gamma delta CAR-T therapy prulacabtagene leucel (prula-cel) produced complete renal responses in 50% of evaluable lupus nephritis (LN) patients and Definition of Remission in Systemic Lupus (DORIS) remission in 54% of evaluable patients at 12 months in a Phase I study. The company plans to begin start-up activities for a pivotal LN study in Q4 2026.
The August 28, 2026 data cut included 22 efficacy-evaluable patients, comprising 16 with LN and six with extra-renal systemic lupus erythematosus (SLE). All had received at least three prior therapies, and 71% had received four or more. Adicet said all 12-month responses remained ongoing through 12 to 21 months of follow-up except in one patient whose urine protein-to-creatinine ratio rose to 0.65 g/g and who remained off immunosuppressants.
All patients discontinued immunosuppressants, while all but one tapered background steroids to 5 mg or less of prednisone equivalent per day. Adicet also reported complete CD19+ B-cell depletion followed by naïve-dominant B-cell reconstitution, which it said was consistent with an immune reset.
Prula-cel is an investigational allogeneic gamma delta CAR-T therapy engineered with an anti-CD20 CAR to deplete B cells. Among 24 safety-evaluable patients, Grade 1 or 2 cytokine release syndrome occurred in 25%, with no cases above Grade 2, and no ICANS, IEC-HS, graft versus host disease, or dose-limiting toxicities were reported.
Adicet said it has aligned with the US FDA on a single-arm pivotal study in LN patients with inadequate response to at least two immunosuppressants, using complete renal response at 12 months as the primary endpoint. The study is expected to enroll a double-digit number of patients. The company also plans to discuss potentially expanding the study to include SLE patients without nephritis with the FDA in Q4 2026.