FDA Approves Besponsa (Inotuzumab Ozogamicin) for Acute Lymphoblastic Leukemia in Adults

Written By:Stacy Simon

The US Food and Drug Administration has approved the targeted therapy drug Besponsa (inotuzumab ozogamicin) for adults with B-cell precursor acute lymphoblastic leukemia (ALL) that is not getting better with treatment, or came back after treatment. B-cell precursor ALL is a type of cancer in which the bone marrow makes too many B-cell lymphocytes, an immature type of white blood cell.

This type of leukemia can get worse very quickly, and if not treated is probably fatal within a few months. A new treatment option is significant because few treatment options are available.

Besponsa is a kind of targeted therapy called an antibody-drug conjugate, a monoclonal antibody linked to a chemotherapy drug. It’s thought to work by attaching to B-cell ALL cancer cells that express the CD22 protein, blocking the growth of cancer cells. It is intended to target and kill only the cancer cells and spare healthy cells.

The FDA based its approval on a randomized clinical trial of people with B-cell ALL who did not get better with treatment, or whose cancer returned after treatment. Participants received either treatment with Besponsa, or standard chemotherapy. Of the 218 people who were evaluated, 35.8% who received Besponsa had a complete remission for an average of 8 months and 17.4% who received standard treatment had a complete remission for an average of 4.9 months.

The FDA approved Besponsa using priority review and breakthrough therapy designations, which are ways to speed up the evaluation of drugs to treat serious conditions. The drug was also granted orphan product designation, which provides incentives to the drug’s developer because treatments for rare diseases are so hard to develop and test.

Besponsa is given as an infusion into the vein. Common side effects included low blood counts, fatigue, severe bleeding, fever, nausea, headache, abdominal pain, abnormal liver tests, and high levels of bilirubin in the blood. Other serious side effects included increased risk of severe liver damage in patients who receive Besponsa after certain kinds of stem cell transplant, infusion-related reactions, and heart problems.  Women who are pregnant or breastfeeding should not take Besponsa because it may cause harm to a developing fetus or a newborn baby.

Besponsa is marketed by Pfizer, Inc.

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