A safety and efficacy study of allogeneic haematopoietic stem cell transplantation for refractory and relapsed T‐cell acute lymphoblastic leukaemia/lymphoblastic lymphoma patients who achieved complete remission after autologous CD7 chimeric antigen receptor T‐cell therapy

Summary CD7‐targeted chimeric antigen receptor T‐cell (CAR‐T) therapy has shown promising initial complete remission (CR) rates in patients with refractory or relapsed (r/r) T‐cell acute lymphoblastic leukaemia and lymphoblastic lymphoma (T‐ALL/LBL). To enhance the remission duration, consolidation with allogeneic haematopoietic stem cell transplantation (allo‐HSCT) is considered. Our study delved into the outcomes of 34 patients with r/r T‐ALL/LBL who underwent allo‐HSCT after achieving CR with autologous CD7 CAR‐T therapy. These were compared with 124 consecutive T‐ALL/LBL patients who received allo‐HSCT in CR following chemotherapy. The study revealed that both the CAR‐T and chemotherapy cohorts exhibited comparable 2‐year overall survival (OS) (61.9% [95% CI, 44.1–78.1] vs. 67.6% [95% CI, 57.5–76.9], p = 0.210), leukaemia‐free survival (LFS) (62.3% [95% CI, 44.6–78.4] vs. 62.0% [95% CI, 51.8–71.7], p = 0.548), non‐relapse mortality (NRM) rates (32.0% [95% CI, 19.0–54.0] vs. 25.3% [95% CI, 17.9–35.8], p = 0.288) and relapse incidence rates (8.8% [95% CI, 3.0–26.0] vs. 15.8% [95% CI, 9.8–25.2], p = 0.557). Patients aged ≤14 in the CD7 CAR‐T group achieved high 2‐year OS and LFS rates of 87.5%. Our study indicates that CD7 CAR‐T therapy followed by allo‐HSCT is not only effective and safe for r/r T‐ALL/LBL patients but also on par with the outcomes of those achieving CR through chemotherapy, without increasing NRM.