Shanghai, China, November 11, 2026
Abbisko Therapeutics has announced that the U.S. Food and Drug Administration (FDA) has approved PIMJETMI® (pimicotinib), an oral small-molecule treatment for certain adults with symptomatic tenosynovial giant cell tumor (TGCT). The medicine is indicated for adults whose disease may cause significant functional limitations or severe morbidity if treated through surgical resection. Pimicotinib is a potent colony-stimulating factor 1 receptor (CSF-1R) inhibitor independently developed by Abbisko and licensed to Merck KGaA, Darmstadt, Germany, for global commercialization. The U.S. approval represents a major regulatory and commercial milestone for Abbisko, marking the fourth marketing approval for the medicine following authorizations in China, Canada and Switzerland. It also introduces a new systemic treatment option for eligible patients living with this rare, locally aggressive tumor.
FDA Approval Supported by Positive Phase III MANEUVER Results
The FDA approval is based on primary and longer-term findings from the global Phase III MANEUVER clinical trial and its open-label extension. In the pivotal study, pimicotinib demonstrated a statistically significant improvement in objective response rate (ORR) at Week 25 compared with placebo. According to the company, the objective response rate assessed by a blinded independent review committee using RECIST version 1.1 was 56% with pimicotinib compared with 3% with placebo. The difference was highly statistically significant, with a reported p-value of less than 0.0001. The medicine also demonstrated improvements across several secondary measures relevant to patients’ everyday activities. These included relative range of motion, physical functioning and pain, with reported p-values of 0.0003, 0.0074 and less than 0.0001, respectively. Longer-term findings from patients initially randomized to pimicotinib showed continued clinical benefit. At a median follow-up of 14.3 months, the median duration of response had not been reached. Importantly, 77% of patients who had achieved a response at Week 25 maintained clinical benefit after an additional 12 months of follow-up. These results provide evidence of sustained tumor response in a substantial proportion of responding patients. The Phase III findings were presented at major oncology meetings, including the American Society of Clinical Oncology (ASCO) Annual Meeting and the European Society for Medical Oncology (ESMO) Congress in 2025.
Oral CSF-1R Inhibitor Targets the Biology of TGCT
Tenosynovial giant cell tumor is a rare tumor that primarily develops in the joints, tendon sheaths and bursae. Although it is generally considered locally aggressive rather than a cancer that commonly spreads throughout the body, TGCT can cause persistent pain, swelling, stiffness and reduced joint movement. These symptoms may significantly affect mobility and quality of life. The disease is associated with overexpression of colony-stimulating factor 1 (CSF-1) in abnormal synovial cells. This signaling promotes the accumulation of CSF-1 receptor-expressing inflammatory cells within the tumor environment. Pimicotinib is designed to inhibit CSF-1R, targeting this biological pathway involved in TGCT development. As an orally administered targeted therapy, it offers a systemic treatment approach for patients who may not be suitable candidates for surgery because resection could lead to worsening functional limitations or substantial morbidity. The FDA authorization is specifically for the indicated adult patient population and should not be interpreted as approval for every person diagnosed with TGCT. Treatment decisions remain dependent on individual clinical circumstances and the approved prescribing information.
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Merck Partnership Strengthens Global Commercialization
The U.S. approval is also significant for Abbisko’s collaboration with Merck KGaA, Darmstadt, Germany, which holds global commercialization rights to pimicotinib under a licensing agreement. With this latest authorization, PIMJETMI® has received marketing approvals in four markets: China, where the National Medical Products Administration approved it in December 2025; Canada, where Health Canada approved it in June 2026; Switzerland, where Swissmedic authorized it in October 2026; and now the United States. The applications in the United States, Canada and Switzerland were reviewed through Project Orbis, an international regulatory collaboration framework initiated by the FDA Oncology Center of Excellence to facilitate coordinated review of oncology medicines among participating regulatory authorities. Abbisko is eligible to receive a milestone payment following the first commercial sale of pimicotinib in the United States, in addition to double-digit royalties on global net sales and potential further payments tied to regulatory, development and commercial milestones. The company described the approval as an important achievement in its development of innovative medicines. For patients with symptomatic TGCT who face difficult surgical treatment decisions, the authorization expands the available treatment options. The milestone also demonstrates how targeted drug development and international commercialization partnerships can help bring therapies for rare tumors to additional markets.
Source: Abbisko Therapeutics press release
