Merck has announced that the US Food and Drug Administration has accepted its new drug application for pimicotinib as a systemic treatment for patients with tenosynovial giant cell tumor (TGCT). The submission is based on primary and longer-term results from the global Phase 3 MANEUVER study, which showed deep and durable tumor responses and meaningful improvements in patient outcomes.

David Weinreich, global head of R&D and chief medical officer for the healthcare business at Merck, said: “With pimicotinib, we have an opportunity to significantly advance care for people living with TGCT, a painful and debilitating disease that has few effective and well-tolerated treatment options beyond surgery. Based on clinical trial results showing not only a reduction in tumor burden, but also the ability to help alleviate symptoms like pain and stiffness in the global Phase 3 MANEUVER study, we are confident in the important role pimicotinib can play for TGCT patients in the U.S. and worldwide.”

In the MANEUVER trial, once-daily pimicotinib demonstrated a statistically significant improvement in the primary endpoint of objective response rate assessed by blinded independent review committee using RECIST v1.1 at week 25, compared with placebo. The study also showed significant improvements across secondary endpoints related to patient-reported outcomes, including active range of motion, physical function, and reductions in stiffness and pain. These findings were presented at the 2025 ASCO Annual Meeting.

Longer-term follow-up, with a median of 14.3 months, presented at ESMO Congress 2025, indicated that the objective response rate continued to increase over time for patients receiving pimicotinib from the start of the study.

TGCT is a rare, locally aggressive tumor that develops in or around the joint and can cause progressive swelling, stiffness, and reduced mobility, significantly affecting daily life in otherwise healthy individuals. If untreated or recurrent, TGCT may lead to irreversible damage to bones, joints, and surrounding tissues. There remains a substantial need for effective, well-tolerated treatments beyond surgery that can shrink tumors, alleviate pain, and restore function.

Merck noted that pimicotinib was approved in December 2025 by the China National Medical Products Administration for adults with symptomatic TGCT where surgical resection could result in functional limitations or severe morbidity. The company said additional regulatory submissions are under review in other markets.