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

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.