Impact of Prior Inotuzumab Ozogamicin Treatment on Brexucabtagene Autoleucel Outcomes in Adults with B-cell ALL

The effect of prior inotuzumab ozogamicin (InO) treatment on brexucabtagene autoleucel (brexu-cel) outcomes remains unclear in adults with acute lymphoblastic leukemia (ALL). We conducted a retrospective multicenter analysis of 189 patients with relapsed/refractory ALL treated with brexu-cel. Over half of the patients received InO before brexu-cel (InO exposed). InO-exposed patients were more heavily pretreated (P = .02) and frequently had active marrow disease before apheresis (P = .03). Response rate and toxicity profile after brexu-cel were comparable for InO-exposed and InO-naïve patients; however, consolidation therapy after brexu-cel response was used at a higher rate in InO-naïve patients (P = .005). With a median follow-up of 11.4 months, InO-exposed patients had inferior progression-free survival (PFS; P = .013) and overall survival (OS; P = .006) in univariate analyses; however, prior InO exposure did not influence PFS (hazard ratio, 1.20; 95% confidence interval, 0.71-2.03) in multivariate models. Within InO-exposed patients, InO responders had superior PFS (P = .002) and OS (P < .0001) relative to InO-refractory patients. The timing of administering InO did not affect brexu-cel outcomes, with comparable PFS (P = .51) and OS (P = .86) for patients receiving InO as bridging therapy or before apheresis. In conclusion, although InO exposure was associated with inferior survival outcomes after brexu-cel in unadjusted analyses, these associations were no longer significant in multivariate analyses, suggesting it is unlikely that InO negatively affects brexu-cel efficacy. Our data instead imply that InO-exposed recipients of brexu-cel tend to be higher-risk patients with intrinsic adverse leukemia biology.