Adicet Bio said its off-the-shelf CAR-T therapy prula-cel produced remissions in a small phase 1 lupus trial, offering an early efficacy signal at a time when autoimmune cell therapy development has been rattled by safety problems elsewhere. One year after treatment, 12 of the 22 evaluated patients had achieved remission of lupus symptoms, and eight of the 16 patients with lupus nephritis had remission of their kidney symptoms.
The combination of activity and tolerability is the main signal here. Adicet said the remissions followed a single dose in patients who had failed multiple prior therapies, while avoiding the serious inflammatory toxicities that recently hit other autoimmune CAR-T programs.
The Data
Adicet’s interim chief medical officer Lloyd Klickstein said the remissions were achieved “off immunosuppression” and were accompanied by biological evidence of an immune reset. According to the company, all patients evaluated in the study, including those who did not reach full remission, have stopped taking their standard immunosuppressants, and all but one have significantly reduced their steroid dose.
Safety is central to how this dataset will be judged. Adicet reported no cases of immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome, or IEC-HS, a serious hyperinflammatory condition. It also reported no cases of immune effector cell-associated neurotoxicity syndrome, or ICANS, and said almost all instances of cytokine release syndrome were grade 1.
Why Adicet Looks Different
The company’s argument is that prula-cel may behave differently because it is built from gamma delta T cells rather than the more common patient-derived approach. CEO Chen Schor told Fierce that these cells naturally reside in tissues rather than circulating in the bloodstream, which he said could make them favorable for autoimmune diseases that damage organs.
Prula-cel also targets CD19 on B cells, which are implicated in diseases such as lupus. Schor said Adicet is seeing early signs of immune system reset, with returning B cells appearing as naive B cells rather than cells associated with disease.
That profile matters because recent events have raised questions around the risk-benefit balance for autoimmune CAR-T. Novartis’ CD19-targeted candidate rap-cel was recently linked to three deaths from IEC-HS in its autoimmune program, and BMS recently paused trials of its CD19-targeted CAR-T zola-cel because of “transient and reversible inflammatory events.”
What To Watch
Adicet plans to keep developing prula-cel as a one-and-done treatment for lupus rather than part of a chronic treatment cocktail. Schor said the FDA has already agreed to a single-arm pivotal trial for lupus nephritis that should start next year, with a likely later expansion into lupus patients without kidney disease.
That next step could determine whether Adicet’s early phase 1 signal becomes a durable competitive position as autoimmune disease emerges as the next commercial target for CAR-T beyond blood cancers.
