The U.S. FDA has approved Merck KGaA's once-daily oral pill Pimjetmi (pimicotinib) for adult patients with symptomatic tenosynovial giant cell tumors ineligible for surgery without severe complications. In the Phase 3 MANEUVER trial, pimicotinib achieved a 54% to 56% response rate at week 25 and reached 76.2% at 14.3 months follow-up, showing no evidence of liver toxicity. Originally licensed from Abbisko Therapeutics, the approval expands Merck KGaA's growing rare tumor portfolio.
Pimicotinib presentation and approval
- ▪Detailed data for pimicotinib were presented during the 2025 annual meeting of the American Society of Clinical Oncology
- ▪The U.S. Food and Drug Administration approved pimicotinib, marketed under the brand name Pimjetmi by Merck KGaA's healthcare division EMD Serono, on November 10, 2026, for adult patients with symptomatic tenosynovial giant cell tumors where surgical removal could worsen joint function or cause severe complications
Phase 3 MANEUVER trial efficacy and safety
- ▪In the Phase 3 MANEUVER trial of 94 patients with no prior exposure to CSF-1R inhibitors, pimicotinib achieved a 54% to 56% overall response rate at 25 weeks compared with 3% for placebo
- ▪In the MANEUVER trial of pimicotinib for tenosynovial giant cell tumor, patients demonstrated significant improvements in joint range of motion, physical function, stiffness, and pain, with 35% reporting grade 3 or 4 adverse events and no evidence of cholestatic hepatotoxicity
- ▪At a median follow-up of 14.3 months in the Phase 3 MANEUVER trial, the overall response rate for pimicotinib reached 76.2%, with nearly 94% of patients experiencing tumor size reduction
Pimicotinib dosing and label precautions
- ▪The prescribing information for pimicotinib includes warnings and precautions for hepatotoxicity, embryo-fetal toxicity, and increased serum creatinine without affecting renal function
- ▪Pimicotinib is administered as a 50 mg oral pill taken once daily with or without food
Mechanism of TGCT and pimicotinib
- ▪Tenosynovial giant cell tumor is a rare, non-cancerous but locally aggressive soft tissue tumor caused by a genetic abnormality that overexpresses colony-stimulating factor 1, which recruits cells that promote tumor growth in joint synovial linings
- ▪Pimicotinib functions as a small molecule colony-stimulating factor 1 receptor tyrosine kinase inhibitor designed to block the receptor that promotes tumor growth
Treatment landscape and global approvals
- ▪Pimicotinib was first approved for tenosynovial giant cell tumor in China in late 2025 and has since received regulatory approvals in Canada and Switzerland while remaining under review in Europe
- ▪Pimicotinib joins two other FDA-approved systemic treatments for tenosynovial giant cell tumor: Daiichi Sankyo's Turalio, approved in 2019 with a black box warning for liver toxicity, and Romvimza, approved in 2025
Merck KGaA licensing and acquisitions
- ▪Merck KGaA secured commercialization rights for pimicotinib in Greater China from Shanghai-based Abbisko Therapeutics in 2023, paying $85 million in 2025 to exercise its option for global rights
- ▪Merck KGaA expanded its rare tumor portfolio by acquiring SpringWorks Therapeutics for $3.9 billion in 2025 and striking a $1.1 billion deal for Silence Therapeutics last month
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