The FDA has given accelerated approval to blinatumomab (Blincyto) for the treatment of pediatric and adolescent patients with Philadelphia chromosome-negative (Ph-) relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL).
Blincyto is a CD19 antibody that binds specifically to CD19 expressed on the surface of cells of B-lineage origin and CD3 expressed on the surface of T cells.
In December 2014, Blincyto was given accelerated approval for adults with (Ph-) relapsed or refractory B-cell precursor ALL.
Complete Remission Outcome Measure Met
The approval of the anti-CD19 immunotherapy in children was based on data from a single-arm phase I/II trial, known as Study 205, which met its primary phase II endpoint of complete remission (CR) within the first 2 cycles of blinatumomab.
The multicenter, dose-finding, efficacy trial included 93 patients aged <18 years with Ph- B-cell precursor ALL who were refractory, had relapsed at least twice, or relapsed after an allogeneic hematopoietic stem cell transplantation (HSCT).
Details of the efficacy and safety data are limited but in the drug’s prescribing information, it is noted that in patients weighing less than 45kg, the most common serious adverse reactions (≥ 2%) included pyrexia, febrile neutropenia, cytokine release syndrome, convulsion, device-related infection, hypoxia, sepsis, and overdose. Adverse reactions of Grade 3 or higher were reported in 88% of patients. Discontinuation of therapy due to adverse reactions occurred in 5% of patients treated with Blincyto. Adverse reactions that led to discontinuation of treatment were CRS and fungal infection. 13 Three patients experienced a fatal adverse event within 30 days of the last dose of Blincyto (2 infection and 1 multi-organ failure after undergoing subsequent HSCT).
The accelerated approval means the drug is available due to the power of the phase II data but the maker of the drug (Amgen) must provide additional data from a pivotal study to keep its approval status. The drug was also granted breakthrough therapy, priority review and orphan drug designations by FDA.