What did the ALLELE trial show?
In the international, open-label, multicenter phase 3 ALLELE trial, patients received tabelecleucel at 2.0 × 10⁶ cells/kg intravenously on days 1, 8, and 15 of each approximately 5-week cycle, with the primary end point of overall response rate (ORR). Among all patients (n = 75), the ORR was 50.7% (95% CI, 38.9%-62.4%), including complete responses in 28.0% and partial responses in 22.7%.6
The ORR was 50.0% among 26 patients with prior HCT and 51.0% among 49 patients with prior SOT. At 12 months, the overall survival (OS) rate was 55.7% among all patients, 78.7% in those with a response, and 28.2% in those without a response; the median OS was 18.4 months (95% CI, 5.7-not evaluable [NE]) overall, NE (95% CI, 18.6 months-NE) in responders, and 3.7 months (95% CI, 1.8-11.0) in nonresponders.
Treatment-emergent serious adverse effects occurred in 62.7% of patients, including 8.0% that were related to treatment, with no instances of tumor flare reactions, infusion-related reactions, cytokine release syndrome, or immune effector cell–associated neurotoxicity syndrome reported.
References
- Atara Biotherapeutics reports that the tabelecleucel biologics license application has been resubmitted to the US Food and Drug Administration. News release. Atara Biotherapeutics, Inc. September 30, 2026. Accessed October 1, 2026. https://tinyurl.com/44cttxj9
- Atara Biotherapeutics provides regulatory and business update on EBVALLO (tabelecleucel). News release. Atara Biotherapeutics. January 12, 2026. Accessed October 1, 2026. https://tinyurl.com/5h34yxtx
- Atara Biotherapeutics provides regulatory and business update on EBVALLO (tabelecleucel). News release. Atara Biotherapeutics. January 16, 2025. Accessed October 1, 2026. https://tinyurl.com/3p9jrrtj
- Atara Biotherapeutics provides regulatory updates on EBVALLO (tabelecleucel). News release. Atara Biotherapeutics. May 5, 2025. Accessed October 1, 2026. https://tinyurl.com/3cekvud5
- Pierre Fabre Pharmaceuticals Inc. announces FDA acceptance and priority review of the biologics license application (BLA) for tabelecleucel for the treatment of Epstein-Barr virus positive post-transplant lymphoproliferative disease (EBV+ PTLD). News release. Pierre Fabre Pharmaceuticals. July 25, 2025. Accessed October 1, 2026. https://tinyurl.com/5hfdh7cn
- Dierick D, Ghobadi A, Baiocchi R, et al. Updated results: multicenter open-label ph 3 study of tabelecleucel for SOT or HCT recipients with EBV+ PTLD after failure of rituximab or rituximab + chemotherapy. Presented at: 51st Annual Meeting of the European Society for Blood and Marrow Transplantation; March 30-April 2, 2025; Florence, Italy. Abstract OS17-03.
