On August 17, 2017, the FDA approved inotuzumab ozogamicin (Besponsa; Pfizer), a targeted therapy, for the treatment of adults with relapsed or refractory B-cell acute lymphoblastic leukemia (ALL). The drug blocks cancer growth by binding to B-cell ALL cells that express CD22. The FDA designated inotuzumab ozogamicin as an orphan drug and applied its priority review for this approval.
“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. These patients have few treatments available and today’s approval provides a new, targeted treatment option,” said Richard Pazdur, MD, Director of the FDA’s Oncology Center of Excellence.
The FDA approval of inotuzumab ozogamicin was based on a randomized clinical trial of 326 patients with relapsed or refractory B-cell ALL who had received 1 or 2 previous treatments. Among the 218 evaluable patients, 35.8% of those receiving inotuzumab ozogamicin achieved complete remission that lasted a median of 8 months. Of the patients who received an alternative chemotherapy regimen, 17.4% achieved complete remission lasting a median of 4.9 months.
The common side effects reported with inotuzumab ozogamicin include thrombocytopenia, neutropenia, leukopenia, infection, anemia, fatigue, hemorrhage, pyrexia, nausea, headache, febrile neutropenia, liver damage, abdominal pain, and hyperbilirubinemia. Serious side effects attributed to the use of inotuzumab ozogamicin include myelosuppression, infusion-related reactions, and QT interval prolongation.
Inotuzumab ozogamicin was approved with a boxed warning about the risk for hepatotoxicity, including veno-occlusive disease or sinusoidal obstruction syndrome, as well as the increased mortality risk in patients who use the drug after certain stem-cell transplants.