The FDA has approved obecabtagene autoleucel for the treatment of adults with relapsed refractory B-cell precursor acute lymphoblastic leukemia.

The approval followed a multicenter, open-label, single-arm trial that enrolled adult patients that relapsed after a remission of 12 months or less, had relapsed or refractory acute lymphoblastic leukemia following at least two prior lines of systemic therapy or had relapsed at least 3 months after allogenic stem cell transplantation.

Rate and duration of complete remission served as the study's main efficacy outcome measurements and were achieved within 3 months of infusion. Additional outcome measures, rate and duration of overall complete remission included complete remission and complete remission with incomplete hematologic recovery at any time.

The trial included 65 patients, of whom 27 achieved complete remission within 3 months (42%; 95% CI, 29%-54%). Cytokine release syndrome (CRS) occurred in 75% and neurologic toxicities occurred in 64%, with immune effector cell-associated neurotoxicity syndrome (ICANS) in 24%.

Adverse events occurring in at least 20% included CRS, unspecified infections, musculoskeletal pain, viral infections, fever, nausea, ICANS, hypotension, pain, fatigue, headache, encephalopathy, bacterial infectious disorders, diarrhea, febrile neutropenia, and hemorrhage.

Obecabtagene autoleucel is to be administered as split dose infusion on Day 1 and Day 10 based on bone marrow blast assessment preceded by fludarabine and cyclophosphamide lymphodepleting chemotherapy. The total recommended dose is 410 X 106 CD19 chimeric antigen receptor-positive viable T-cells.