Merck KGaA, through its recently acquired SpringWorks Therapeutics, has received authorization from the European Commission (EC) to market Ogsiveo (nirogacestat) in the EU for the treatment of desmoid tumors, a rare subset of soft tissue sarcomas.
Ogsiveo is an oral gamma secretase inhibitor designed be a monotherapy for adults with progressing desmoid tumors who need systemic treatment. It is the first and only therapy approved in the EU to treat desmoid tumors. The approval was granted based on results of the phase 3 DeFi trial carried out on 142 patients. The drug was found to reduce the risk of disease progression by 71% compared to the placebo. It also had an objective response rate of 41% (compared to 8% with the placebo) and complete response rate of 7% (compared 0% with the placebo).
Ogsiveo was approved by FDA for use in the U.S. back in November 2023, based on same phase 3 DeFi trial results.
Merck KGaA picked up the drug earlier this year through its $3.9 billion acquisition of SpringWorks Therapeutics. SpringWorks’ rare tumor portfolio includes Gomekli, a MEK inhibitor was approved in February 2025 for the treatment of both adults and children with neurofibromatosis type 1 (NF1) who have symptomatic plexiform neurofibromas — tumors that grow along the peripheral nerve sheath and can cause severe disfigurement, pain and functional impairment — that can’t be removed through surgery.