Prulacabtagene leucel (prula-cel, formerly ADI-001)

September 28, 2026: Adicet Bio (NASDAQ: ACET) reported Phase 1 data for prulacabtagene leucel (prula-cel) in systemic lupus erythematosus (SLE) with or without lupus nephritis (LN). At an August 28, 2026 cutoff, 22 patients were efficacy-evaluable (16 LN, 6 extra-renal SLE) with 6-21 months of follow-up; 13 had at least 12 months. At 12 months, 50% of evaluable LN patients achieved complete renal response and 54% of evaluable patients achieved DORIS remission. All 12-month responses were ongoing through 12-21 months except one patient with UPCR 0.65 g/g who remained off immunosuppressants. Mean SLEDAI-2K and PGA scores fell rapidly; 85% of patients with 12-month follow-up had PGA below 0.5.

Safety across 24 dosed patients was described as generally well tolerated: no CRS above Grade 2, Grade 1/2 CRS in 25%, no DLTs, no IEC-HS, no ICANS, no GvHD, and Grade ≥3 infections in 8.3%. All patients discontinued immunosuppressants, and all but one tapered steroids to 5 mg/day prednisone equivalent or less. Biomarkers showed undetectable CD19+ B cells in 22/22 patients, anti-dsDNA reductions in 10/11 baseline-positive patients, and complement recovery in 9/10 with low baseline complement.

Adicet said it aligned with FDA on a single-arm pivotal LN study for patients inadequately responsive to at least two immunosuppressants, with complete renal response at 12 months as the primary endpoint. Startup is planned for 4Q 2026, with possible expansion to non-renal SLE subject to FDA alignment. Upcoming milestones: systemic sclerosis data in 1H 2027 and LN/SLE data in mid-2027.