Abbisko and Merck KGaA Drug Achieves Key Goal in Rare Tumor Study

Abbisko Therapeutics has announced promising results from a Phase III trial of their experimental drug, pimicotinib, for treating tenosynovial giant cell tumour (TGCT). This drug has met the primary endpoint of the study and achieved all key secondary goals. Merck KGaA, which has a marketing license for pimicotinib in China and certain Asian countries through a recent agreement, also has the option for global commercialization rights.

The Phase III study, known as the MANEUVER trial, involved 94 TGCT patients eligible for systemic therapy who had not previously received anti-CSF-1/CSF-1R therapy. Participants were randomly assigned to either pimicotinib or a placebo, administered once daily for a 24-week period. The study's primary goal was the objective response rate (ORR), which Abbisko reported to be 54% for pimicotinib by week 25, compared to just 3.2% for the placebo group.

Additionally, pimicotinib demonstrated statistically significant and clinically meaningful improvements in secondary endpoints related to patient outcomes in TGCT. These secondary measures included reductions in stiffness, assessed by the Numeric Rating Scale, and pain, evaluated using the Brief Pain Inventory. The trial indicated that pimicotinib was generally well-tolerated among participants. Treatment-emergent adverse events (TEAEs) led to treatment discontinuation in 1.6% of patients on the drug, and dose reductions were necessary in 7.9% of cases due to TEAEs.

Yaochang Xu, Abbisko's chief executive, expressed enthusiasm about collaborating with Merck to pursue the registration of pimicotinib as the first systemic treatment option for TGCT in China. Xu highlighted that this drug represents a significant advancement within the emerging class of CSF-1R inhibitors.

Previously, in 2019, Daiichi Sankyo's CSF1 inhibitor, Turalio (pexidartinib), received approval in the US for treating adults with symptomatic TGCT. This approval was based on Phase III data showing a 38% objective response rate among those treated with Turalio, with no responses seen in the placebo group. Meanwhile, Ono Pharmaceutical’s Deciphera Pharmaceuticals unit has submitted an application for their CSF1R inhibitor, vimseltinib, for TGCT treatment, with a decision anticipated from US regulators by February 17 of next year.

Overall, the Phase III results for pimicotinib indicate strong potential for effective management of TGCT, offering hope for a new standard of care in this area. The collaboration between Abbisko Therapeutics and Merck KGaA is poised to bring this innovative treatment to market, potentially improving outcomes for patients with TGCT.