Blinatumomab maintenance after allogeneic hematopoietic cell transplantation for B-lineage acute lymphoblastic leukemia
Mahmoud Gaballa, Pinaki P. Banerjee, Denái R. Milton, Xianli Jiang, Christina Ganesh, Sajad Khazal, Vandana Nandivada, Sanjida Islam, Mecit Kaplan, May Daher, Rafet Başar, Amin M. Alousi, Rohtesh S. Mehta, Gheath Alatrash, Issa F. Khouri, Betül Oran, David Marín, Uday Popat, Amanda Olson, Priti Tewari, Nitin Jain, Elias Jabbour, Farhad Ravandi, Hagop M. Kantarjian, Ken Chen, Richard E. Champlin, Elizabeth J. Shpall, Katayoun Rezvani, Partow Kebriaei
Abstract
Patients with B-lineage acute lymphoblastic leukemia (ALL) are at high-risk for relapse after allogeneic hematopoietic cell transplantation (HCT). We conducted a single-center phase 2 study evaluating the feasibility of 4 cycles of blinatumomab administered every 3 months during the first year after HCT in an effort to mitigate relapse in high-risk ALL patients. Twenty-one of 23 enrolled patients received at least 1 cycle of blinatumomab and were included in the analysis. The median time from HCT to the first cycle of blinatumomab was 78 days (range, 44 to 105). Twelve patients (57%) completed all 4 treatment cycles. Neutropenia was the only grade 4 adverse event (19%). Rates of cytokine release (5% G1) and neurotoxicity (5% G2) were minimal. The cumulative incidence of acute graft-versus-host disease (GVHD) grades 2 to 4 and 3 to 4 were 33% and 5%, respectively; 2 cases of mild (10%) and 1 case of moderate (5%) chronic GVHD were noted. With a median follow-up of 14.3 months, the 1-year overall survival (OS), progression-free survival (PFS), and nonrelapse mortality (NRM) rates were 85%, 71%, and 0%, respectively. In a matched analysis with a contemporary cohort of 57 patients, we found no significant difference between groups regarding blinatumomab's efficacy. Correlative studies of baseline and posttreatment samples identified patients with specific T-cell profiles as "responders" or "nonresponders" to therapy. Responders had higher proportions of effector memory CD8 T-cell subsets. Nonresponders were T-cell deficient and expressed more inhibitory checkpoint molecules, including T-cell immunoglobulin and mucin domain 3 (TIM3). We found that blinatumomab postallogeneic HCT is feasible, and its benefit is dependent on the immune milieu at time of treatment. This paper is posted on ClinicalTrials.gov, study ID: NCT02807883.