FDA Approves Moxetumomab Pasudotox-tdfk for the Treatment of Hairy Cell Leukemia


The U.S. Food and Drug Administration (FDA) today approved moxetumomab pasudotox-tdfk (Lumoxiti) injection for intravenous use for the treatment of adult patients with relapsed or refractory hairy cell leukemia (HCL) who have received at least two prior systemic therapies, including treatment with a purine nucleoside analog. Moxetumomab pasudotox-tdfk is a CD22-directed cytotoxin and is the first of this type of treatment for patients with HCL.

“[Moxetumomab pasudotox-tdfk] fills an unmet need for patients with hairy cell leukemia whose disease has progressed after trying other FDA-approved therapies,” said Richard Pazdur, MD, Director of the FDA’s Oncology Center of Excellence and Acting Director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research. “This therapy is the result of important research conducted by the National Cancer Institute that led to the development and clinical trials of this new type of treatment for patients with this rare blood cancer.”

HCL is a rare, slow-growing cancer of the blood in which the bone marrow overproduces lymphocytes. HCL is named after these extra B cells, which look “hairy” when viewed under a microscope. As the number of leukemia cells increases, fewer healthy white blood cells, red blood cells, and platelets are produced.

The efficacy of moxetumomab pasudotox-tdfk was studied in Study 1053, a phase III single-arm, open-label clinical trial of 80 patients who had received prior treatment for HCL with at least two systemic therapies, including a purine nucleoside analog. The trial measured durable complete response, defined as maintenance of hematologic remission for more than 180 days after achievement of a complete response. Thirty percent of patients in the trial achieved a durable complete response, and the overall response rate was 75%.

Safety Profile

Common side effects of moxetumomab pasudotox-tdfk include infusion-related reactions, edema, nausea, fatigue, headache, pyrexia, constipation, anemia, and diarrhea.

The recommended dose of moxetumomab pasudotox-tdfk is 0.04 mg/kg administered as a 30-minute intravenous infusion on days 1, 3, and 5 of each 28-day cycle for a maximum of 6 cycles or until occurrence of disease progression or unacceptable toxicity.

The prescribing information for moxetumomab pasudotox-tdfk includes a boxed warning to advise health-care professionals and patients 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 include difficulty breathing; weight gain; hypotension; or swelling of arms, legs, and/or face.

The boxed warning also notes the risk of hemolytic uremic syndrome, a condition caused by the abnormal destruction of red blood cells. Patients should be made aware of the importance of maintaining adequate fluid intake, and blood chemistry values should be monitored frequently. Other serious warnings include decreased renal function, infusion-related reactions, and electrolyte abnormalities. Women who are breastfeeding should not be given moxetumomab pasudotox-tdfk.

The FDA granted this application Fast Track and Priority Review designations. Moxetumomab pasudotox-tdfk also received Orphan Drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.