FDA Approves Pimicotinib for Symptomatic Tenosynovial Giant Cell Tumor: Mechanism, Dosing and MANEUVER Data

　　Pimicotinib is an oral,highly selective colony-stimulating factor 1 receptor(CSF-1R)inhibitor approved by the FDA in November 2026 for certain adults with symptomatic tenosynovial giant cell tumor(TGCT).TGCT arises in joints and periarticular tissues and can cause pain,swelling,and restricted movement.When surgery may cause substantial functional loss or serious complications,systemic therapy may be considered.

　　Mechanistically,CSF-1/CSF-1R signaling contributes to the TGCT microenvironment and recruitment or survival of CSF-1R–expressing cells.By inhibiting CSF-1R,pimicotinib reduces pathway signaling that supports disease activity,thereby helping control tumor burden and symptoms.

　　The approved population includes adults with symptomatic TGCT in whom surgery would likely worsen functional limitation or produce serious complications.The recommended regimen is pimicotinib 50mg orally once daily,with or without food.Treatment duration,interruption,or dose adjustment should follow the prescribing information and individual response.

　　Efficacy is supported by the international phase III MANEUVER trial,a randomized,double-blind,placebo-controlled study using a 2:1 allocation to pimicotinib 50mg once daily or placebo.The primary endpoint was objective response rate(ORR)at week 25:56%with pimicotinib versus 3.2%with placebo.Secondary outcomes,including range of motion,pain,and physical function,also favored pimicotinib.Among week-25 responders,91%maintained response for at least 6 months and 77%for at least 12 months;median duration of response was not reached.

　　Common adverse reactions include pruritus,rash,facial edema,periorbital edema,fatigue,nausea,headache,and peripheral edema.Laboratory abnormalities may include increased creatine phosphokinase,lactate dehydrogenase,transaminases,lipase,cholesterol,amylase,and serum creatinine without clear renal impairment.The label warns about hepatotoxicity and embryofetal toxicity;hepatic tests,pregnancy status,and relevant laboratories should be monitored per the prescribing guidelines.

　　Pimicotinib previously received FDA fast track and breakthrough therapy designations and was reviewed through the Project Orbis international oncology collaboration.For selected adults with symptomatic,surgically inappropriate TGCT,it provides an oral targeted option,but use should be individualized based on tumor site,surgical risk,reproductive plans,and safety monitoring.