BOSTON—EMD Serono, the Healthcare business of Merck KGaA, Darmstadt, Germany, in the U.S. and Canada, announced new long-term data from the global Phase 3 MANEUVER trial evaluating pimicotinib, an investigational colony stimulating factor-1 receptor (CSF-1R) inhibitor developed by Abbisko Therapeutics Co., Ltd., for the treatment of tenosynovial giant cell tumor (TGCT). The updated analysis, presented at the European Society for Medical Oncology (ESMO) Congress 2025, showed that with a median follow-up of 14.3 months, pimicotinib produced continued improvements in tumor response, pain, and function.
The data demonstrated that the objective response rate (ORR) by blinded independent review committee (BIRC) per RECIST v1.1 increased from 54 percent at Week 25 to 76.2 percent (95% CI: 63.8, 86.0). Clinically meaningful gains were also observed in patient-reported outcomes, including mobility, pain reduction, and functional recovery. The safety profile remained consistent with previously reported results, with no new safety concerns identified.
“With the initial MANEUVER study results presented earlier this year at ASCO, pimicotinib achieved the highest objective response rate ever seen in a Phase 3 trial of a systemic TGCT therapy,” said Prof. Niu Xiaohui, Director of the Bone and Soft Tissue Tumour Diagnosis and Research Centre at Beijing Jishuitan Hospital. “These new findings confirm that the benefits of pimicotinib are not only durable but deepen over time, with patients reporting improved pain, mobility, and quality of life. This supports pimicotinib’s potential to become a best-in-class treatment for TGCT.”
TGCT is a rare, often debilitating disease that can cause joint pain, stiffness, swelling, and loss of mobility. “TGCT can make simple daily activities difficult and emotionally draining,” said Sydney Stern, Ph.D., M.S., of TGCT Support, a program of the Life Raft Group. “A therapy that reduces tumor size and alleviates pain helps patients regain control of their lives and reconnect with their families and communities.”
The MANEUVER trial included 63 patients who received pimicotinib for 24 weeks and continued treatment in an open-label extension. Key results included:
• ORR per BIRC by RECIST v1.1 rose to 76.2 percent (95% CI: 63.8, 86.0), up from 54 percent at Week 25.
• ORR per BIRC by tumor volume score (TVS), a TGCT-specific measure, increased to 74.6 percent (95% CI: 62.1, 84.7), from 61.9 percent at Week 25.
• Median duration of response had not been reached, with 93.7 percent of patients showing tumor shrinkage.
Pimicotinib also showed continued improvement through Week 73 in patient-reported outcomes, including:
• A mean 23.9 percent improvement from baseline in relative range of motion, up from 15.6 percent at Week 25.
• Sustained improvements in physical function (PROMIS-PF scale) and reductions in stiffness and pain scores.
Among patients initially assigned to placebo and later switched to pimicotinib (n=31), the ORR reached 64.5 percent by both RECIST v1.1 and TVS, with a median follow-up of 8.5 months.
No new safety issues emerged in the long-term follow-up. There were no cases of cholestatic hepatotoxicity, drug-induced liver injury, or hair/skin hypopigmentation, and most adverse events were mild and manageable.
“These longer-term data reinforce pimicotinib’s potential to change the treatment landscape for TGCT by providing a durable, systemic option that reduces tumor burden while helping patients restore mobility and relieve pain,” said Victoria Zazulina, M.D., Head of Development Unit, Oncology, for the Healthcare business of Merck KGaA, Darmstadt, Germany. “We are actively working with regulators worldwide to make this treatment available to patients as soon as possible.”
An application for marketing authorization of pimicotinib as a Class 1 innovative drug for adult TGCT patients has been accepted for review by the China National Medical Products Administration (NMPA). Additional submissions are planned in the U.S. and other global markets.
