Recently, Abbisko Therapeutics announced that the New Drug Application (NDA) for pimicotinib hydrochloride capsules, a novel orally administered small-molecule CSF-1R inhibitor independently developed by the company for the systemic treatment of tenosynovial giant cell tumor (TGCT), has been formally accepted for review by the U.S. Food and Drug Administration (FDA). This milestone marks a critical step forward in the product’s regulatory progress across major global markets and creates new international momentum for the treatment of this rare disease.

The FDA’s acceptance of the NDA is primarily based on positive results from the global, multicenter, randomized, double-blind, placebo-controlled Phase III MANEUVER study. The study demonstrated that TGCT patients receiving once-daily oral pimicotinib achieved a significantly higher objective response rate (ORR) at Week 25, as assessed by a blinded independent review committee in accordance with RECIST v1.1 criteria, compared with the placebo group. In addition, all key secondary endpoints closely associated with disease burden showed clinically meaningful improvements, including increased range of motion and physical function, as well as significant reductions in pain and stiffness. Long-term follow-up data with a median follow-up of 14.3 months further indicated that tumor response rates continued to improve over time among patients receiving continuous pimicotinib treatment, demonstrating durable and sustained efficacy.

Tenosynovial giant cell tumor is a rare, locally aggressive tumor arising in or around joints, often leading to joint swelling, stiffness, pain, and restricted mobility, which can severely impair patients’ daily activities and work capacity. The pathogenesis of TGCT is closely linked to the overexpression of colony-stimulating factor 1 (CSF-1) by tumor cells, resulting in abnormal accumulation of inflammatory cells expressing the CSF-1 receptor (CSF-1R). Historically, TGCT treatment has relied primarily on surgical resection; however, high recurrence rates and the risk of functional impairment—particularly in patients with complex lesions or multiple surgeries—have left a substantial unmet need for effective systemic therapies.

Pimicotinib hydrochloride is a novel, oral, highly selective, and potent small-molecule CSF-1R inhibitor developed by Abbisko Therapeutics. By selectively blocking the CSF-1/CSF-1R signaling pathway, pimicotinib intervenes in disease progression at the mechanistic level. The product has previously received multiple regulatory recognitions worldwide, including designation as a Breakthrough Therapy by China’s National Medical Products Administration (NMPA), Breakthrough Therapy Designation from the U.S. FDA, and Priority Medicines (PRIME) designation from the European Medicines Agency (EMA).

In China, pimicotinib hydrochloride capsules were approved by the NMPA in 2025 for the treatment of adult patients with symptomatic TGCT for whom surgical resection may result in functional limitation or severe complications. The drug is the first domestically developed innovative therapy approved in China for the systemic treatment of TGCT and the third product globally approved for this indication. Notably, approval was granted just over six months after NDA acceptance, and the review process included successful on-site inspections of overseas clinical trial centers, underscoring the robustness of the clinical data and the rigor of the company’s development system.

From a commercialization perspective, Abbisko Therapeutics entered into a global licensing agreement with Merck KGaA, Germany, in 2023, under which Merck is responsible for worldwide commercialization of pimicotinib and has exercised its option for global commercialization rights. In addition to the United States, marketing applications for pimicotinib are currently under review in multiple other countries and regions.

With the FDA’s formal acceptance of the pimicotinib NDA, the drug’s global registration strategy is accelerating. Industry experts believe that pimicotinib has the potential to offer TGCT patients a once-daily, oral, effective, and well-tolerated systemic treatment option, and to further advance a shift in the treatment paradigm for this rare disease.

The compound patent application for pimicotinib was filed under PCT application WO2018214867A1 and has entered 19 countries or regions, including China, the United States, the European Union, Japan, South Korea, Australia, and Canada, where it has been granted in all jurisdictions. In China, the granted patent publication number is CN110573500B, with a filing date of May 22, 2018, and an estimated expiration date of May 22, 2038. The broad geographic scope of granted patents indicates a high level of inventiveness, suggesting a relatively robust patent position and enabling the patent holder to enjoy more than a decade of market exclusivity.