FDA Approves IV Treatment for HCL

The U.S. Food and Drug Administration (FDA) has approved moxetumomab pasudotox-tdfk for the treatment of adult patients with relapsed or refractory hairy cell leukemia (HCL) who have received at least two prior therapies. This is the first CD22-directed cytotoxin approved to treat HCL.

The FDA’s decision was based on results from a single-arm, open-label clinical trial of 80 patients with relapsed or refractory HCL. Participants received moxetumomab pasudotox-tdfk 40 µg/kg intravenously over 30 minutes on days 1, 3, and 5 of 28-day cycles, for a maximum of six cycles or until disease progression, unacceptable toxicity, initiation of alternate therapy, or complete response (CR).

The overall response rate was 75 percent, and 30 percent of patients who received moxetumomab pasudotox-tdfk achieved CR, defined as maintenance of hematologic remission for more than 180 days. Common adverse events included infusion-related reactions, edema, nausea, fatigue, headache, pyrexia, constipation, anemia, and diarrhea.

“[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.

Moxetumomab pasudotox-tdfk also was granted fast-track, priority-review, and orphan-drug designations.

Source: FDA press release, September 13, 2018.