FDA Approves Lumoxiti (Moxetumomab Pasudotox) for Hairy Cell Leukemia

The US Food and Drug Administration (FDA) has approved Lumoxiti (moxetumomab pasudotox-tdfk) for adults with hairy cell leukemia (HCL) that did not get better with at least 2 different previous treatments or got better but then came back.

HCL is a form of chronic lymphocytic leukemia, a cancer that starts in the bone marrow. The bone marrow makes too many B cells (lymphocytes), a type of white blood cell that normally helps fight infection. HCL gets its name from the way the cells look under the microscope -- they have fine projections on their surface that make them look "hairy."

Lumoxiti is a conjugated monoclonal antibody, which works by delivering a toxic substance directly to the cancer cells, limiting its effects on healthy cells. This is the first drug of this type approved to treat people with HCL.

The FDA based its approval on a clinical trial of 80 people with HCL who had already tried at least 2 other treatments including a purine nucleoside analog, a type of chemotherapy. The trial measured the percentage of patients who showed a complete response to Lumoxiti (meaning all signs of leukemia were gone) and then remained in remission for at least 6 months. Thirty percent of trial participants achieved this result. Overall, 75% had either a complete response or a partial response to the treatment.

The FDA evaluated Lumoxiti through its fast track and priority review programs, which are meant to speed up the availability of drugs to treat serious diseases. Lumoxiti also received orphan product designation, which provides incentives to developers for drugs intended to treat a rare disease.

Lumoxiti is given as an intravenous (IV) injection. Common side effects include infusion-related reactions, swelling, nausea, fatigue, headache, fever, constipation, diarrhea, and low levels of red blood cells (anemia).

The prescribing information for Lumoxiti includes a Boxed Warning about the risk of developing capillary leak syndrome, a condition in which fluid and proteins leak out of tiny blood vessels into surrounding tissues. Symptoms of capillary leak syndrome can include trouble breathing, weight gain, low blood pressure, and swelling of arms, legs, or face. The Boxed Warning also notes the risk of hemolytic uremic syndrome, caused by the abnormal destruction of red blood cells. Patients are advised to drink plenty of fluids while taking Lumoxiti and will need to have frequent blood testing. Other serious warnings include: decreased kidney function, infusion-related reactions, and electrolyte abnormalities. Women who are breastfeeding should not take Lumoxiti.

Lumoxiti is marketed by AstraZeneca Pharmaceuticals.