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0 > Adicet Bio Adicet Bio Announces Positive Safety and Efficacy Data from Prula - cel ( formerly ADI - 001 ) Study in Patients with Systemic Lupus Erythematosus with or without Lupus Nephritis September 28 , 2026 - Prula - cel shown to be generally well tolerated with no CRS greater than Grade 2 and no IEC - HS or ICANS - -At 12 - months , 54 % of evaluable patients achieved DORIS remission and 50 % of patients achieved CRR- -All patients discontinued immunosuppressants - - All but one patient tapered background steroids to ≤5 mg prednisone equivalent per day- -Rapid reductions in SLEDAI - 2K and PGA scores , consistent with autologous alpha beta CAR - T cell therapies- -Plan to initiate pivotal lupus nephritis trial start - up activities in 4Q / 2026 ; high DORIS remission rate may support expansion of pivotal study to include lupus without nephritis based on regulatory precedent- -Company to host investor webcast at 8:00 am ET today- REDWOOD CITY , Calif .-- ( BUSINESS WIRE ) -- Sep . 28 , 2026-- Adicet Bio , Inc. ( Nasdaq : ACET ) , a clinical - stage biotechnology company discovering and developing allogeneic gamma delta CAR - T cell and in vivo CAR - T therapies for autoimmune diseases , hematologic malignancies and solid tumors , today announced safety and efficacy data from the Phase 1 study evaluating prulacabtagene leucel ( prula - cel ) as a potential treatment for patients with systemic lupus erythematosus ( SLE ) with or without lupus nephritis ( LN ) . The data cut as of August 28 , 2026 includes 22 efficacy evaluable patients ( 16 LN patients and 6 extra - renal SLE patients ) . All patients have follow - up of at least 6 months , and 13 patients have at least 12 months of follow - up . Based on these findings , the Company plans to initiate start - up activities for a pivotal study in LN in the fourth quarter of 2026 . Given the high Definition of Remission in Systemic lupus ( DORIS ) remission rate observed in the study , the pivotal study may expand to include lupus patients without nephritis . " We are excited to report clinical data for prula - cel reinforcing its potential to deliver meaningful , lasting remission after a single treatment for patients with SLE , including those with lupus nephritis , " said Lloyd Klickstein , M.D. , Ph.D. , Interim Chief Medical Officer and a Member of the Board of Directors . " We observed complete renal responses and DORIS remissions after a single dose of prula - cel in patients who had failed multiple prior therapies . Notably , these remissions were achieved off immunosuppression and were accompanied by biological evidence of an immune reset . In a disease where chronic therapy with limited efficacy and significant tolerability and safety considerations remains the standard of care , the prospect of durable , treatment - free remission after a single treatment could be transformative for individuals living with lupus . " " Today's results mark an exciting step forward for Adicet and for lupus patients with or without nephritis . 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 Chen Schor , President and Chief Executive Officer of Adicet Bio " Importantly , the compelling efficacy data observed to date has been accompanied by a generally favorable safety profile with no cases of IEC - HS , no ICANS and no CRS beyond Grade 2 reported in the study . 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. " Data highlights as of August 28 , 2026 , cut - off date were as follows : • 22 patients ( 16 LN and 6 extra renal SLE ) were evaluated with follow - up ranging from 6-21 months . • Efficacy endpoints . Prula - cel treatment yielded high rates of immunosuppressant - free responses in a heavily pretreated population . Patients had a mean baseline of Systemic Lupus Erythematosus Disease Activity Index 2000 ( SLEDAI - 2K ) of 13 and those with LN had mean urine protein - to - creatinine ratio ( UPCR ) of 2.8 , and all had received at least three prior therapies ( 71 % received four or more ) . At the 12 - month mark , 50 % of evaluable lupus nephritis patients achieved a complete renal response ( CRR ) and 54 % of evaluable patients achieved DORIS remission . All 12 - month responses were ongoing at 12 to 21 months of follow - up , except 1 patient with UPCR 0.65 g / g who remains off immunosuppressants . Reductions in mean SLEDAI - 2K and Physician's Global Assessment ( PGA ) were rapid and sustained , consistent with autologous alpha beta CD19 CAR - T therapies , and 85 % of patients with 12 - month follow - up achieved a PGA score below 0.5 . • Safety Profile . As of August 28 , 2026 , prula - cel was generally well tolerated and showed a favorable safety profile appropriate for outpatient dosing . Across the 24 safety - evaluable patients dosed with prula - cel , there was no cytokine release syndrome ( CRS ) greater than Grade 2. Grade 1 or 2 CRS occurred in 25 % of patients . There were no dose - limiting toxicities ( DLTs ) , no immune effector cell - associated hemophagocytic lymphohistiocytosis - like syndrome ( IEC - HS ) , and no Immune Effector Cell - Associated Neurotoxicity Syndrome ( ICANS ) . Infections were reported in 54 % of patients , with Grade 3 or higher in 8.3 % . There were no cases of graft vs host disease ( GvHD ) observed . Per alignment with the U.S. Food and Drug Administration ( FDA ) , this profile supports outpatient administration . • Immunosuppression and steroids . All patients discontinued immunosuppressants , and all but one tapered background