The the US Food and Drug Administration (FDA) has granted approval to Daiichi Sankyo's Turalio (pexidartinib) capsules for the treatment of adult patients with symptomatic tenosynovial giant cell tumour (TGCT) associated with severe morbidity or functional limitations and not responsive to improvement with surgery.

The approval was based on the results of a multi-center international clinical trial of 120 patients, which found that there was a statistically significant improvement in overapp response rate (ORR) in patients who received Turalio, with an ORR of 38%, compared to no responses in patients who received placebo. The complete response rate was 15% and the partial response rate was 23%.

TGCT can cause “debilitating symptoms for patients such as pain, stiffness and limitation of movement. The tumour can significantly affect a patient’s quality of life and cause severe disability,” said Richard Pazdur, director of the FDA’s Oncology Centre of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research.

He continued, “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.”

GCT is a rare tumour that affects the synovium (thin layer of tissue that covers the surfaces of the joint spaces) and tendon sheaths (layer of membrane that covers tendons, which are fibrous tissue that connect muscle to bone). The tumour is rarely malignant but causes the synovium and tendon sheaths to thicken and overgrow, causing damage to surrounding tissue.