Adicet Bio, Inc. (NASDAQ:ACET) reported Phase 1 clinical data for prulacabtagene leucel, or prula-cel, its investigational allogeneic gamma delta CAR-T cell therapy, in patients with systemic lupus erythematosus with or without lupus nephritis.
The data cutoff was August 28, 2026, and included 22 efficacy-evaluable patients, comprising 16 with lupus nephritis and six with extra-renal systemic lupus erythematosus.
Follow-up ranged from six to 21 months. All patients had previously received at least three therapies, while 71% had received four or more.
Adicet Reports Remission and Renal Response Data
At 12 months, 54% of evaluable patients achieved DORIS remission, according to the company.
Among evaluable patients with lupus nephritis, 50% achieved a complete renal response at 12 months.
All patients discontinued immunosuppressants, while all but one reduced background steroid treatment to 5 mg or less of prednisone equivalent per day.
Adicet also reported that all 22 efficacy-evaluable patients achieved undetectable levels of CD19+ B cells, followed by naïve-dominant B-cell reconstitution.
Reductions in anti-dsDNA antibodies were observed in 91% of patients who were positive for the antibodies at baseline.
Safety Data Cover 24 Patients
The safety analysis included 24 evaluable patients.
No cytokine release syndrome above Grade 2 was reported. Grade 1 or Grade 2 cytokine release syndrome occurred in 25% of patients.
The company reported no cases of immune effector cell-associated hemophagocytic syndrome, immune effector cell-associated neurotoxicity syndrome, dose-limiting toxicities or graft-versus-host disease.
Infections were reported in 54% of safety-evaluable patients, with Grade 3 or higher infections occurring in 8.3%.
According to Adicet, the U.S. Food and Drug Administration has aligned with the company on outpatient administration based on the reported safety profile.
Pivotal Lupus Nephritis Study Planned
Adicet plans to begin start-up activities for a pivotal single-arm study of prula-cel in patients with lupus nephritis during the fourth quarter of 2026.
The planned study will use complete renal response at 12 months as its primary endpoint.
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 in the Phase 1 study.
Adicet expects to provide a clinical data update in systemic sclerosis during the first half of 2027, followed by an additional lupus nephritis and systemic lupus erythematosus data update by mid-2027.