Daratumumab and venetoclax-based combined regimen for relapsed/refractory T-lymphoblastic leukemia/lymphoma

Abstract Objective: To investigate the efficacy and safety of a treatment regimen combining Daratumumab (Dara) with Venetoclax (Ven) in patients suffering from relapsed/refractory T-lymphoblastic leukemia/lymphoma (T-ALL/LBL). Methods: From January 2023 and January 2024, twelve patients with relapsed/refractory T-ALL/LBL received a combined treatment regimen based on Dara and Ven. The cohort consisted of 9 males and 3 females, with a median age of 25 (range:15-57) years. Within each 28-day treatment cycle, Dara was scheduled to administer at a dosage of 16mg/kg once weekly for 4 weeks, while Ven was given at 400mg daily for 21 days, within each 28-day cycle. Additionally, some patients received liposomal mitoxantrone and pegaspargase as part of their treatment. Results: The combined regimen of Dara and Ven achieved an overall response rate (ORR) of 75.0%, with a complete remission (CR) rate of 58.8%. Among the 12 patients, seven had not previously undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT). Of these, four achieved CR, one-achieved partial remission (PR), and two did not respond. Of the four CR patients who subsequently underwent allo-HSCT as consolidation therapy, three remained disease-free, while one relapsed. The PR patient and one non-remission (NR) patient died due to disease progression after different chemotherapy regimens. Another NR patient died early after salvage transplantation due to infection. Five patients were enrolled post-allo-HSCT. Four of them relapsed after the first transplantation, and one developed a secondary neoplasm. Among these, three patients (60.0%) achieved CR, with two remaining disease-free; one relapsed and underwent a second allo-HSCT. Of the other two patients, one achieved PR, and one failed to respond. Both of them died due to disease progression. For all 12 patients, the one-year overall survival (OS) was 58.3% (95%CI27.0%-80.1%), and the median survival was not reached. The one-year progression-free survival (PFS) of 9 patients who achieved response was 53.3% (95%CI 17.7%-79.6%), the one-year OS for the 5 patients after transplantation was 60.0% (95%CI 12.6%-88.2%), and the PFS of 4 responded patients was 50.0% (95%CI 5.8%-84.5%). Only 2 patients experienced infusion reactions related to Dara with no serious treatment-related adverse events. Conclusion: The Dara and Ven regimen demonstrates a high response rate and well-tolerated treatment option for patients with relapsed/refractory T-ALL/LBL. It can serve as a bridging treatment for patients who have not undergone allo-HSCT. For patients who experience relapse after allo-HSCT, it can also be used as a maintenance therapy to extend disease-free survival.