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FDA Okays Pfizer Antibody-Drug Conjugate for Pediatric ALL
The US Food and Drug Administration has expanded the indication of inotuzumab ozogamicin (Besponsa, Pfizer) to include children aged ≥ 1 year with relapsed or refractory CD22-positive B-cell precursor acute lymphoblastic leukemia (ALL).
The CD22-directed antibody and cytotoxic drug conjugate was previously approved only for adults with the condition.
Pediatric approval was based on a single-arm study of 53 children, of whom 12 were treated with an initial dose of 1.4 mg/m2/cycle and the rest with an initial dose of 1.8 mg/m2/cycle for a median of two cycles and a range of one to four cycles.
Premedications included methylprednisolone plus an antipyretic and antihistamine.
Overall, 22 children (42%) had a complete remission, defined as < 5% blasts in the bone marrow, no leukemia blasts in peripheral blood, full recovery of peripheral blood counts, and resolution of extramedullary disease. The median duration of complete remission was 8.2 months.
All but one child who went into complete remission (95.5%) had no minimal residual disease (MRD) by flow cytometry, and 19 (86.4%) were MRD negative by real-time quantitative polymerase chain reaction.
Adverse events in ≥ 20% of participants included thrombocytopenia, pyrexia, anemia, vomiting, infection, hemorrhage, neutropenia, nausea, leukopenia, febrile neutropenia, increased transaminases, abdominal pain, and headache.
The antibody-drug conjugate carries a black box warning of hepatotoxicity, including hepatic veno-occlusive and post-hematopoietic stem cell transplant mortality.
The initial recommended dose is 1.8 mg/m2 per cycle, divided into 0.8 mg/m2 on day 1, followed by 0.5 mg/m2 on day 9 and 0.5 mg/m2 on day 15. The initial 3-week cycle can be extended to 4 weeks for patients who have a complete remission or a complete remission with incomplete hematologic recovery and/or to recover from toxicities.
According to drugs.com, 0.9 mg costs $23,423.47.
M. Alexander Otto is a physician assistant with a master's degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape. Alex is also an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com.
