The data come from Part C of the Phase 1/2 RAINFOL-01 trial, which tested Rina-S 120 mg/m² every three weeks in a heavily pretreated population – 53% had received three or four prior lines of therapy. Five patients had complete responses, median duration of response was 12.1 months, and 51% of responders were still in response at one year. Median progression-free survival was 9.5 months. Activity was seen regardless of folate receptor alpha (FRα) expression level, including in patients with low or no FRα expression.

Treatment discontinuation due to adverse events occurred in 5.5% of patients, and no signals were seen for ocular toxicity, peripheral neuropathy or interstitial lung disease. The results were presented as a late-breaker at the IGCS 2026 congress in Montreal. Rina-S is being evaluated in four Phase 3 trials across gynecologic cancers.

“These findings, including the observed antitumor activity, duration of response, and the first progression-free survival data reported for the program, as well as the manageable tolerability, reinforce the potential of Rina-S,” says Tahamtan Ahmadi, Chief Medical Officer, Genmab.