Adicet Bio has reported positive Phase I safety and efficacy data for prulacabtagene leucel (prula-cel), its investigational allogeneic gamma delta CAR T therapy, in patients with systemic lupus erythematosus (SLE), with or without lupus nephritis.
The dataset included 22 efficacy-evaluable patients, 16 with lupus nephritis and six with extra-renal SLE, all of whom had at least six months of follow-up. Thirteen had reached at least 12 months of follow-up. At the 12-month mark, 54 percent of evaluable patients achieved Definition of Remission in Systemic Lupus (DORIS) remission, while 50 percent of evaluable lupus nephritis patients achieved a complete renal response.
All patients discontinued immunosuppressant treatment, while all but one reduced background corticosteroids to 5 mg or less of prednisone equivalent per day. According to Adicet, responses observed at 12 months were generally maintained through 12–21 months of follow-up.
Prula-cel (formerly ADI-001) was also reported to be generally well tolerated in patients. Among 24 safety-evaluable patients, no cytokine release syndrome (CRS) above Grade 2 was recorded. Grade 1 or 2 CRS occurred in 25 percent of patients, while there were no cases of immune effector cell-associated neurotoxicity syndrome, IEC-HS, graft-versus-host disease, or dose-limiting toxicities. Infections were reported in 54 percent of patients, including Grade 3 or higher infections in 8.3 percent.
Prula-cel is designed as an off-the-shelf gamma delta CAR T therapy targeting B cells through an anti-CD20 CAR. All 22 efficacy-evaluable patients achieved undetectable CD19-positive B cells followed by naïve-dominant B-cell reconstitution, which the company described as evidence of an “immune reset.”
“The data suggests prula-cel has the potential to offer lupus patients a highly differentiated treatment option: a single dose, off-the-shelf therapy, with a favorable safety profile, that may lead to immunosuppressant free remission,” said President and CEO of Adicet Bio, Chen Schor. “Combined with the FDA’s support of outpatient administration of prula-cel, and the scalability of our off-the-shelf manufacturing, these findings support the potential of prula-cel to redefine the treatment expectations for patients living with systemic lupus erythematosus with or without lupus nephritis. We look forward to progressing towards a potentially pivotal study by the end of 2026.”
Adicet has aligned with the FDA on plans for a single-arm pivotal study in lupus nephritis patients who have responded inadequately to at least two immunosuppressants. Start-up activities are expected to begin in the fourth quarter of 2026, with the company also planning discussions with the agency over potentially including patients with lupus without nephriti
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