The Food and Drug Administration (FDA) has approved Besponsa (inotuzumab ozogamicin; Pfizer) for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL).

Besponsa 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 is based on results from the Phase 3 randomized, multicenter trial (INO-VATE), which included 326 patients with relapsed or refractory B-cell ALL who had received 1 or 2 prior treatments. The patients were randomized to either receive Besponsa or an alternative chemotherapy regimen.

Study results demonstrated that 35.8% of those who received Besponsa experienced complete remission (CR) for a median of 8 months, compared to the alternative chemotherapy group in which 17.4% experienced CR for a median of 4.9 months.

The Besponsa labeling includes a boxed warning that severe liver damage (hepatotoxicity), including blockage of veins in the liver (veno-occlusive disease [VOD] or sinusoidal obstruction syndrome), occurred in some patients who took Besponsa. The warning also states an increased risk of death for those who take Besponsa after receiving a certain type of stem cell transplant. 

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The INO-VATE lead study investigator Hagpop M. Kantarijan, MD, said of the trial that, “Besponsa improved multiple efficacy measures, including rates of hematologic remission, MRD-negativity and stem cell transplantation.”

“These patients [with B-cell ALL who did not respond to initial treatment] 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 had previously granted Priority Review and Breakthrough Therapy as well as Orphan Drug designation to Besponsa.

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