Inotuzumab

Tisagenlecleucel (tisa-cel) and brexucabtagene autoleucel (brexu-cel) are approved CD19 chimeric antigen receptor T-cell therapy (CAR T) products for young adults (YA) with relapsed/refractory B-cell acute lymphoblastic leukemia. A distinct analysis of YAs receiving commercial CD19 CAR T has not been reported. Using retrospective data from the Pediatric Real-World CAR T Consortium and the Real-World Outcomes of CAR T in Adult ALL collaboration, we describe the efficacy and safety of tisa-cel and brexu-cel in 70 YAs (18-26 years; tisa-cel, n = 50; brexu-cel, n = 20). Cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS) were observed more frequently for brexu-cel vs tisa-cel (CRS, 85% vs 56%; ICANS, 40% vs 18%). Complete response rates were similar between products at 80% for brexu-cel and 88% for tisa-cel. Relapse-free survival (RFS) at 12 months was 46% for brexu-cel and 36% for tisa-cel. Durability of remission over 12 months was 61% for brexu-cel vs 41% for tisa-cel; 12-month overall survival (OS) for brexu-cel was 84% vs 68% for tisa-cel. In multivariate analysis, low disease burden was associated with improved OS, whereas inotuzumab before CAR T was associated with inferior outcomes. This study demonstrates comparable real-world efficacy among YAs receiving CD19 CAR T irrespective of CAR T construct; however, rates of toxicity seem higher with brexu-cel.

The treatment landscape for relapsed or refractory acute lymphoblastic leukemia (RR ALL) has evolved significantly with the introduction of monoclonal antibodies such as blinatumomab and inotuzumab ozogamicin. These agents have demonstrated remarkable efficacy, achieving high response rates and minimal residual disease (MRD) negativity. However, the optimal selection, sequencing, and integration of monoclonal antibodies and other modalities like standard chemotherapy or chimeric antigen receptor T‐cell therapy remain areas of active investigation. The absence of direct comparative studies has led to reliance on indirect analyses, which provide conflicting results regarding the relative benefits of inotuzumab and blinatumomab. While inotuzumab is preferred in high‐disease‐burden settings due to its cytoreductive capabilities, blinatumomab shows superior performance in low‐disease‐burden settings by leveraging preserved T‐cell function. Sequential and combination approaches, such as induction with inotuzumab followed by blinatumomab consolidation, may optimize outcomes, particularly for patients undergoing subsequent allogeneic stem cell transplantation (alloSCT). The interval between inotuzumab and alloSCT is critical to mitigate the risk of veno‐occlusive disease (VOD). Despite these advances, the prognosis for patients with high‐risk genetic lesions, such as TP53 mutations, remains poor, underscoring the need for innovative therapeutic strategies. As monoclonal antibodies increasingly move into frontline therapy, their role in relapse settings must be redefined. Future research should focus on unraveling the molecular underpinnings of resistance and refining treatment paradigms to improve survival and quality of life for patients with RR ALL.