Adicet Bio, Inc. (Nasdaq: ACET) released Phase 1 clinical data for prulacabtagene leucel (prula-cel), an investigational allogeneic gamma delta CAR-T cell therapy, in patients with systemic lupus erythematosus (SLE) with or without lupus nephritis (LN), according to a company statement.

The data, cut off as of August 28, 2026, covered 22 efficacy-evaluable patients — 16 with LN and 6 with extra-renal SLE — with follow-up ranging from 6 to 21 months. All patients had received at least three prior therapies, with 71% having received four or more.

At 12 months, 54% of evaluable patients achieved DORIS remission, and 50% of evaluable LN patients achieved a complete renal response. All patients discontinued immunosuppressants, and all but one tapered background steroids to 5 mg or less of prednisone equivalent per day.

Among 24 safety-evaluable patients, no cytokine release syndrome greater than Grade 2 was reported, with Grade 1 or 2 CRS occurring in 25% of patients. There were no cases of IEC-HS, ICANS, dose-limiting toxicities, or graft versus host disease. Infections were reported in 54% of patients, with Grade 3 or higher in 8.3%. The U.S. Food and Drug Administration has aligned with the company on outpatient administration based on this profile.

All 22 efficacy-evaluable patients achieved undetectable CD19+ B cells, followed by naïve-dominant B-cell reconstitution. Anti-dsDNA antibody reductions were observed in 91% of baseline-positive patients.

Adicet Bio plans to initiate start-up activities for a pivotal single-arm study in LN patients in the fourth quarter of 2026, with a primary endpoint of complete renal response at 12 months. The company also plans to discuss with the FDA a potential expansion of the pivotal study to include lupus patients without nephritis, citing the DORIS remission rate observed.

A clinical data update in systemic sclerosis is anticipated in the first half of 2027, with an additional LN/SLE data update expected by mid-2027.