Core Insights - Genmab A/S announced updated data from the Phase 1/2 RAINFOL™-01 trial for rinatabart sesutecan (Rina-S), showing a 50.0% confirmed objective response rate (ORR) in advanced endometrial cancer patients [2][7][8] - The study included 64 heavily pretreated patients, with 63.6% of responders maintaining their responses at a median follow-up of one year [2][4] - Rina-S has received Breakthrough Therapy Designation from the U.S. FDA for advanced endometrial cancer [7][8] Study Details - The RAINFOL-01 trial is an open-label, multicenter Phase 1/2 study evaluating Rina-S at various doses in solid tumors expressing folate receptor alpha (FRα) [9] - The B2 cohort specifically evaluated the efficacy and safety of Rina-S in patients with advanced or recurrent endometrial cancer, with doses of 100 mg/m² and 120 mg/m² administered [4][9] - The confirmed ORR for the 100 mg/m² cohort was 50.0%, while the 120 mg/m² cohort showed a 44.1% ORR [4][5] Safety Profile - Common treatment emergent adverse events (TEAEs) included cytopenias and low-grade gastrointestinal events, with serious TEAEs occurring in 36.4% of patients on the 100 mg/m² dose and 52.4% on the 120 mg/m² dose [5] - No significant ocular toxicities, neuropathy, or interstitial lung disease (ILD) were reported in the clinical trials [5] Future Development - Continued evaluation of Rina-S is ongoing in the Phase 2 RAINFOL-01 trial and the Phase 3 RAINFOL-03 trial for endometrial cancer [3][6] - Genmab is also advancing Rina-S in a Phase 3 trial for platinum-resistant ovarian cancer [6][11] Industry Context - Endometrial cancer is the second most prevalent gynecologic cancer globally, with increasing incidence and limited treatment options for advanced cases [10] - Rina-S targets FRα, which is overexpressed in multiple tumors, presenting a promising therapeutic opportunity in a market with no approved FRα-directed therapies for endometrial cancer [10][11]