With the CSF-1R inhibitor space heating up, Merck KGaA has gone all-in on pimicotinib, paying Abbisko Therapeutics $85 million to secure the global license to the drug.
The German pharma originally paid $70 million for the greater China commercialization rights back in 2023, while retaining an option to expand its interest to cover the rest of the world. Japanese pharma Daiichi Sankyo has already shown that inhibiting the colony-stimulating factor 1 receptor can work in tenosynovial giant cell tumors (TGCTs) after winning FDA approval for Turalio in 2019, but Merck identified a gap for another drug in the class.
That $70 million investment looked like a good bet last November when a phase 3 trial in patients with TGCTs showed that 54% of people on pimicotinib had responded at 25 weeks, compared to just 3.2% of the placebo cohort.
Now, Merck said it has made the decision to pay the $85 million option fee to secure the rights to commercialize pimicotinib in the rest of the world. The pharma also has the option to codevelop the drug for “additional indications under certain conditions,” according to the April 1 press release.
The expanded deal puts Shanghai-based Abbisko in line for up to $605.5 million in total payments—including the upfront fees as well as development and commercial milestones—alongside a share of royalties should pimicotinib make it to market.
“Pimicotinib represents a key advancement within the emerging class of CSF-1R inhibitors, demonstrating a meaningful clinical efficacy and safety profile that positions it as an innovative treatment option for worldwide TGCT patients,” Abbisko CEO Yao-Chang Xu said in the release.
“We look forward to deepening our collaboration with the Merck team to expedite the registration process of pimicotinib to bring benefits to patients as quickly as possible,” the CEO added.
Daiichi’s CSF-1R inhibitor Turalio generated 5.1 billion Japanese yen ($33 million) of sales during the last nine months of 2024, up 25% year over year. But pimicotinib could also find itself in competition with Ono Pharmaceutical’s CSF-1R inhibitor vimseltinib, which bagged FDA approval for TGCTs last month.