This study will consist of 2 parts. In Part 1, pexidartinib 800 mg/day (400 mg twice a day [BID]) will be administered on an empty stomach and tolerability and PK of pexidartinib will be evaluated to determine the initiation of Part 2. In Part 2, pexidartinib 800 mg/day (400 mg BID) will be administered on an empty stomach and efficacy, safety, and PK of pexidartinib will be evaluated.
This phase 2, multicenter, two-part, open-label, single-arm study will be conducted in Japan and will evaluate the safety, tolerability, pharmacokinetics (PK), and efficacy of pexidartinib in adult participants with symptomatic tenosynovial giant cell tumor (TGCT) associated with severe morbidity or functional limitation and not amenable to improvement with surgery.