Merck KGaA/Abbisko report positive phase 3 results for pimicotinib in rare tumor type

Merck KGaA and Abbisko Therapeutics have revealed promising outcomes from a late-stage clinical trial involving pimicotinib for patients with tenosynovial giant cell tumours (TGCTs). The phase 3 MANEUVER trial assessed the efficacy of pimicotinib in TGCT patients who were eligible for systemic treatment and had not undergone previous anti-CSF-1/CSF-1R therapy.

The trial successfully achieved its main goal, demonstrating an objective response rate at week 25 of 54% for pimicotinib compared to just 3.2% for the placebo group. Additionally, pimicotinib showed significant and clinically relevant improvements in secondary endpoints related to TGCT patient outcomes, such as reductions in stiffness and pain.

The companies reported that the drug was well tolerated by patients, with a safety profile consistent with prior data. TGCT is a rare, non-cancerous but locally aggressive condition originating in the synovial lining of joints, bursae, and tendon sheaths. Symptoms include joint pain, stiffness, swelling, and limited range of motion. If untreated or recurrent, the disease can lead to irreversible damage to bones, joints, and nearby tissues.

Developed by Abbisko, pimicotinib is an orally administered, highly selective, and potent small-molecule inhibitor of CSF-1R. It has already received breakthrough therapy designation in both the US and China, and priority medicine designation in the EU for its potential in treating TGCT.

In December of the previous year, Merck and Abbisko entered into an agreement granting Merck exclusive rights to commercialize pimicotinib in mainland China, Hong Kong, Macau, and Taiwan, with an option for global commercialization.

Danny Bar-Zohar, the global head of research and development and chief medical officer for Merck's healthcare business sector, stated: “This phase 3 data from MANEUVER confirms results of Abbisko’s phase 1 study, indicating that targeting CSF-1R with pimicotinib has the potential to offer a new treatment option for patients. As we work with Abbisko to review the data from this study and prepare to share it with regulators in China, we are focused on our shared goal of bringing pimicotinib to patients in need.”