Study of Pimicotinib (ABSK021) for Tenosynovial Giant Cell Tumor (MANEUVER)

Inclusion Criteria: * Patients should understand the study procedures and sign the informed consent form prior to screening. * Age ≥ 18 years. * A histologically confirmed TGCT with unresectable. * Measurable disease as defined by RECIST 1.1, and with at least one lesion of ≥ 2 cm. * Stable prescription of analgesic regimen for patients with an analgesic need. * Participants should complete stiffness and pain scales during the screening period, and symptomatic disease because of active TGCT should meet minimum requirements as outlined in study protocol. * ECOG PS (Eastern Cooperative Oncology Group Performance Status) of 0 or 1. * Adequate organ function and bone marrow function. Exclusion Criteria: * Known allergy or hypersensitivity to any components of the investigational drug product. * Previous treatment with highly selective inhibitors targeting CSF-1/CSF-1R. Previous therapy with imatinib and nilotinib is allowed. * Known additional malignancy that required active treatment and may affect the patient's participation in the study or affect the outcome of the study as assessed by the Investigator. * Known metastatic TGCT. * Significant concomitant arthropathy in the affected joint, serious disease, uncontrolled infection. * Known MRI contraindications. * Has factors that significantly affected the absorption of oral drug. * Major surgery or previous anti-tumor therapy for TGCT within 4 weeks prior to randomization. * Concomitant use of strong CYP inhibitors or inducers as outlined in study protocol. * Impaired cardiac function or clinically significant cardiac disease. * Known active human immunodeficiency virus, active hepatitis B, active hepatitis C, or known active tuberculosis. * Known active liver or biliary disease, or other diseases that may lead to abnormal liver function test results during the study. * Pregnant or lactating women. * Childbearing potential males or non-surgically sterilized female patients must agree to use effective methods of contraception during the study. * Any other clinically significant comorbidities, which in the judgment of the Investigator, could compromise compliance with the protocol, interfere with the interpretation of study results, or predispose the patient to safety risks.