FDA approved on August 17 inotuzumab ozogamicin (Besponsa—Pfizer) for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL). The targeted therapy is thought to work by binding to B-cell ALL cancer cells that express the CD22 antigen, blocking the growth of cancerous cells. "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, MD, director of FDA's Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in FDA's Center for Drug Evaluation and Research. "These patients have few treatments available and today's approval provides a new, targeted treatment option." A randomized trial involving more than 300 patients with relapsed or refractory B-cell ALL who had received one or two previous treatments was used to investigate the safety and efficacy of inotuzumab ozogamicin. Of the 218 patients who were evaluated, 35.8% of patients in the inotuzumab ozogamicin group achieved complete remission (CR) for a median 8.0 months, while 17.4% of patients who received an alternative chemotherapy regimen experienced CR for a median 4.9 months. Frequently reported adverse effects of inotuzumab ozogamicin include thrombocytopenia, neutropenia and leukopenia, infection, anemia, fatigue, hemorrhage, pyrexia, nausea, headache, febrile neutropenia, transaminases and/or gamma-glutamyltransferase increased, abdominal pain, and hyperbilirubinemia. The prescribing information for the drug includes a boxed warning that severe liver damage—including blockage of veins in the liver or sinusoidal obstruction syndrome—occurred in some patients who took inotuzumab ozogamicin. The boxed warning also lists an increased risk of death for patients who take inotuzumab ozogamicin after receiving a certain type of stem cell transplant. Other serious adverse effects of the drug include a decrease in blood cell and platelet production, infusion-related reactions, and QT interval prolongation.