Placebo-controlled randomized, double-blind study of zaltoprofen for patients with diffuse type tenosynovial giantcell tumor (Pigmented Villonodular Synovitis) and unresectable localized tenosynovial giant cell tumor (tendon sheath giant cell tumor) (Phase II study)

INTERVENTION: Intervention type:DRUG. Intervention1:Zaltoprofen, Dose form:TABLET, Route of administration:ORAL, intended dose regimen:In the zaltoprofen group, 2 tablets of zaltoprofen (80 mg) 3 times a day with water of 1 cup or more (about 150 mL) or more after oral administration. Gastric mucosa protective agent is orally administered in regular dosage and dose as a concomitant medicine.. Control intervention1:Placebo, Dose form:TABLET, Route of administration:ORAL, Intended dose regimen:In placebo group, 2 placebo tablets orally 3 times a day with water of 1 cup or more (about 150 mL) or more after oral administration. Gastric mucosa protective agent is orally administered in regular dosage and dose as a concomitant medicine.. CONDITION: Diffuse type tenosynovial giant cell tumor (Pigmented Villonodular Synovitis) and localized tenosynovial giant cell tumor (tendon sheath giant cell tumor) PRIMARY OUTCOME: Progression‐free rate at 48 weeks after drug administration (Definition of exacerbation is "serious event requiring surgical intervention") ; Evaluate as exacerbation if it falls under any one or more of the following serious events requiring surgical intervention. If (1) and (2) are evaluated every 4 weeks and judged as exacerbation twice in succession, if (3), (4), (5) are evaluated once every 12 weeks and e valuated once Judgment of exacerbation. . Timepoint:48 weeks. SECONDARY OUTCOME: (1) Progression‐free rate (24 weeks a nd 48 weeks) ; (2) Maximum Standarized Uptake Value (SUV) change rate by FDG‐PET; (3) Evaluation of affected limb function (baseline, 24 weeks, 48 weeks): The Japanese Orthopedic Association score, MSTS score ; (4) Percentage of cases in which clinical benefit about pain, range of motion of joint, joint function compared with baseline is observed at 24 weeks and 48 weeks (judgment by investigator clinical trial physician); (5) Types, incidence and severity of a dverse events and abnormal laboratory data (graded using CTCAE v4.0), The severity and the relationship with the investigational drug will be evaluated. Timepoint: (1)(3)(4)24weeks and 48 weeks, (2)48weeks, (5)anytime during the trial period. INCLUSION CRITERIA: Patients who satisfy all of the following conditions are included. (1) Patients who sufficiently are explained the research purpose, interests and disadvantages before starting the examination about the clinical trial, understand it, and obtained written informed consent. No substitute is allowed. (2) Patients who are diagnosed as diffuse type tendinous synovial giant cell tumor (pigmented chorionic synovitis) or unresectable localized tendonous synovial giant cell tumor occurred in the knee joint or ankle by radiological findings and pathological findings (3) Patient with measurable lesion based on RECIST v1.1 with at least one knee joint or ankle joint. (4) Patients who keep joint space in the knee joint or ankle joint in standing X‐ray imaging. (5) Patients aged 20 years or older and under 70 years old at the time of acquisition. (6) In the case of a pregnant woman,a patient whose pregnancy test to be conducted during the screening period is neg