FDA Accepts Merck’s New Drug Application for Pimicotinib in Tenosynovial Giant Cell Tumor
Merck, a global leader in science and technology, has announced that the U.S. Food and Drug Administration (FDA) has accepted its New Drug Application (NDA) for pimicotinib, an investigational systemic therapy for the treatment of patients with tenosynovial giant cell tumor (TGCT). The FDA’s acceptance marks a significant regulatory milestone and brings pimicotinib one step closer to becoming a potential new treatment option for patients living with this rare, chronic, and often debilitating disease.
The NDA submission is supported by robust clinical evidence from the global Phase 3 MANEUVER study, including both primary efficacy results and longer-term follow-up data. Findings from the study demonstrated that pimicotinib achieved deep and durable tumor responses while also delivering clinically meaningful improvements in symptoms and functional outcomes that matter most to patients.
TGCT is a rare, locally aggressive tumor that develops in or around joints, most commonly affecting the knee, hip, ankle, or hand. Although the tumor is not typically life-threatening, it can cause progressive swelling, stiffness, pain, and reduced mobility, significantly impairing quality of life. TGCT often affects younger, otherwise healthy adults during their most active years, making its functional and psychosocial impact particularly profound. Surgical removal remains the standard of care, but many patients experience recurrence, incomplete resection, or long-term joint damage, underscoring the need for effective systemic therapies.
“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,” said David Weinreich, Global Head of Research and Development and Chief Medical Officer for Merck’s Healthcare business. “The results from the MANEUVER study showed not only meaningful reductions in tumor burden, but also improvements in symptoms such as pain, stiffness, and physical function. These outcomes reinforce our confidence in the potential role pimicotinib can play for TGCT patients in the U.S. and around the world.”
The Phase 3 MANEUVER trial evaluated once-daily oral pimicotinib in patients with TGCT who were not suitable candidates for surgery or for whom surgery would be associated with unacceptable morbidity. At week 25, pimicotinib demonstrated a statistically significant improvement in the primary endpoint of objective response rate (ORR), as assessed by a blinded independent review committee using RECIST v1.1 criteria, compared with placebo.
In addition to tumor shrinkage, the study showed statistically significant and clinically meaningful improvements across all key secondary endpoints related to patient-reported outcomes. These included improvements in active range of motion and physical function, as well as reductions in joint stiffness and pain—symptoms that are central to the daily burden of TGCT. Together, these findings suggest that pimicotinib may not only control disease progression but also help patients regain mobility and improve their ability to perform everyday activities.
Data from the MANEUVER study were presented at major international oncology meetings, highlighting the growing recognition of TGCT as an area of unmet medical need. Primary results were shared at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, while longer-term follow-up data were presented at the 2025 European Society for Medical Oncology (ESMO) Congress. With a median follow-up of 14.3 months, the ESMO data demonstrated that the objective response rate continued to increase over time among patients treated with pimicotinib from the start of the study, supporting the durability of response observed in earlier analyses.
If left untreated, or in cases of recurrent disease, TGCT can lead to irreversible damage to bone, cartilage, and surrounding soft tissues. This damage may result in chronic pain, loss of joint function, and, in severe cases, permanent disability. As a result, there is a strong and ongoing demand for treatments that can effectively reduce tumor burden while preserving joint integrity and improving long-term outcomes.
Pimicotinib has already achieved regulatory success outside the United States. In December 2025, the drug was approved by the China National Medical Products Administration (NMPA) for the treatment of adult patients with symptomatic TGCT for whom surgical resection would likely cause functional limitations or significant morbidity. This approval marked an important validation of pimicotinib’s clinical value and provided access to patients in a major global market.
Merck has also submitted additional regulatory applications in other regions, reflecting its broader strategy to make pimicotinib available to patients worldwide. With the FDA’s acceptance of the NDA, the U.S. regulatory review process is now underway, representing a critical step toward potentially expanding treatment options for TGCT patients who currently have limited non-surgical alternatives.
As Merck continues to advance pimicotinib through the regulatory process, the company remains focused on addressing unmet needs in rare and underserved diseases, with the goal of delivering innovative therapies that improve both clinical outcomes and quality of life for patients.
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