A Study of Pexidartinib in Tenosynovial Giant Cell Tumor in Japan

A Phase 2, Multicenter, Two-Part, Open-Label Study of Pexidartinib in Adult Subjects With Tenosynovial Giant Cell Tumor in Japan

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.

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.

Inclusion Criteria:

• Age ≥20 years
• A diagnosis of TGCT (i) that has been histologically confirmed by a pathologist1 and (ii) associated with severe morbidity or functional limitations and not amenable to improvement with surgery determined consensually by qualified personnel (eg, 2 surgeons or a multi-disciplinary tumor board).
• Measurable disease as defined by RECIST version 1.1 (except that a minimal size of 2 cm is required), assessed from MRI scan by a central radiologist.

Exclusion Criteria:

• Known metastatic TGCT.
• Pre-existing increased serum transaminases; total bilirubin or direct bilirubin (>upper limit of normal); or active liver or biliary tract disease, including increased alkaline phosphatase.
• Significant concomitant arthropathy in the affected joint, serious illness, uncontrolled infection, or a medical or psychiatric history that, in the Investigator's opinion, would likely interfere with a participant's study participation or the interpretation of his or her results.
• Use of strong cytochrome P450 3A inducers, including St John's wort, proton pump inhibitors and potassium-competitive acid blockers, or other products known to cause hepatotoxicity.