The U.S. Food and Drug Administration (FDA) has approved Besponsa (inotuzumab ozogamicin) for treating adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL).
The approval for this rare blood cancer comes with a boxed warning for hepatotoxicity, as well as a warning of increased risk of death if Besponsa is taken after certain stem cell transplants.
B-cell precursor ALL is an aggressive cancer in which an excess of B-cell lymphocytes are produced. Initial treatment involves chemotherapy, but for relapsed or refractory patients, effective treatment options are limited.
Per the FDA: “For adult patients with B-cell ALL whose cancer has not responded to initial treatment or has returned after treatment, life expectancy is typically low,” said
Richard Pazdur, M.D., director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “These patients have few treatments available and today’s approval provides a new, targeted treatment option.”
Besponsa is a targeted therapy that is thought to work by binding to B-cell ALL cancer cells that express the CD22 antigen, blocking the growth of cancerous cells.
The approval of Responsa was based on a Phase 3 study of patients with relapsed or refractory B-cell ALL who were randomized to receive treatment with Besponsa (n=109) or an alternative chemotherapy regimen (fludarabine plus cytarabine with G-CSF, high-dose cytarabine, or cytarabine plus mitoxantrone; n=109).
One hundred and nine patients received Besponsa at a starting dose of 1.8 mg/m2
each cycle, which consisted of a 0.8 mg/m2
dose on day 1 followed by 0.5 mg/m2
on day 8 and day 15, which is the FDA recommended dose. In the chemotherapy arm, 109 patients received physicians’ choice of fludarabine plus cytarabine with G-CSF, high-dose cytarabine, or cytarabine plus mitoxantrone.
The study found that 35.8% in the Besponsa-treated group experienced a complete remission for a median 8.0 months compared to 17.4% in the chemotherapy arm that experienced a complete remission for a median 4.9 months.
Common side effects (>20% of patients) associated with Besponsa include thrombocytopenia, neutropenia, leukopenia, infection, anemia, fatigue, hemorrhage, pyrexia, nausea, headache, febrile neutropenia, liver damage (transaminases and/or gamma-glutamyltransferase increased), abdominal pain and hyperbilirubinemia.
Besponsa is manufactured by Pfizer Inc.
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