On Friday, the U.S. Food and Drug Administration (FDA) approved the first-ever therapy for the treatment of a rare disease called tenosynovial giant cell tumors (TGCT).
The agency approved pexidartinib (Turalio) for “adults with symptomatic TGCT associated with severe morbidity or functional limitation and not responsive to surgery.”
The FDA approval came with the requirement of a boxed warning that will mention a risk of potentially serious liver disease, along with a Risk Evaluation and Mitigation Strategy to monitor for liver injury.
Dr. Richard Pazdur of the FDA Office of Hematology and Oncology Products said, “TGCT can significantly affect a patient’s quality of life and cause severe disability. Surgery is the primary treatment option, but some patients are not eligible for surgery, and tumors can recur, even after the procedure. Today’s approval is the first FDA-approved therapy to treat this rare disease.”
The disease arises in the synovial membrane that covers the surface of joint spaces and tendon sheaths. The tumor is rarely malignant; however, it causes overgrowth and thickening of the synovial membrane and tendon sheaths, damaging the surrounding tissues.
More than 15,000 people develop localized TGCT every year, which is benign and can be cured with surgery. However, over 1,500 TGCT cases are diffuse at diagnosis, which cannot always be treated with surgery.
Turalio inhibits colony-stimulating factor-1 receptor, which is the primary driver of the abnormal cell, leading to TGCT.
The FDA approval came after considering the efficacy from an international clinical trial that involved 120 patients with TGCT – half of then received pexidartinib and others placebo. In May, the FDA Oncologic Drugs Advisory Committee had voted in majority to recommend pexidartinib approval, despite its potential to cause liver toxicity.
