On November 8, 2024, the US Food and Drug Administration (FDA) approved obecabtagen autoleucel for use in relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL). It is an autologous 41BB-ζ anti-CD19 CAR T cell with intermediate-affinity scFv. The results of the FELIX clinical trial, which prompted the FDA's decision, were officially published in the New England Journal of Medicine almost 20 days later. They were conducted by Claire Roddie from University College London and her colleagues from the UK, Spain, and the US.
Of the 94 participants in the phase 2A multicenter trials, remission was achieved in 77 percent over a median observation period of 20.3 months, with complete remission achieved in 55 percent and complete remission achieved in 21 percent with incomplete recovery of hematological parameters. Severe (grade 3 and higher) treatment-related adverse events were observed relatively rarely: cytokine release syndrome in 2.4 percent and ICAN syndrome in 7.1 percent of participants.