EU Clears SpringWorks’ Ogsiveo as First Desmoid Tumor Drug

The European Commission has granted marketing authorisation for SpringWorks Therapeutics’ Ogsiveo (nirogacestat) as a monotherapy for adults with progressing desmoid tumors who require systemic treatment, making it the first therapy approved for the rare soft-tissue tumour in the European Union. Approval was underpinned by results from the 142-patient Phase 3 DeFi study, in which the oral gamma-secretase inhibitor cut the risk of disease progression or death by 71% compared with placebo (hazard ratio 0.29; p<0.001) and achieved a 41% objective response rate versus 8% for placebo. Patient-reported outcomes showed significant reductions in pain and improvements in quality of life. Desmoid tumors affect an estimated 1,300 to 2,300 people each year in Europe. Until now, no medicines had been authorised in the region; treatment guidelines have been shifting toward systemic therapy as first-line care. Ogsiveo has been the U.S. standard of care since its FDA clearance in November 2023. Common adverse events observed across trials included diarrhea (85%), rash (65%) and ovarian toxicity in women of child-bearing potential (60%). SpringWorks, majority-owned by Merck KGaA, plans to leverage its rare-disease infrastructure in Europe to launch Ogsiveo alongside its recently approved neurofibromatosis therapy.