Genmab Reports Durable Rina-S Responses in Ovarian Cancer

Copenhagen, Denmark, October 3, 2026

Rina-S Shows Meaningful Responses in Platinum-Resistant Disease

The Part C cohort of the RAINFOL-01 study evaluated Rina-S as a monotherapy in patients with platinum-resistant high-grade serous ovarian cancer, primary peritoneal cancer, or fallopian tube cancer. Patients had received between one and three prior lines of therapy, while those previously treated with mirvetuximab soravtansine could have received up to four prior lines. More than half of the participants, 53%, had received three or four previous treatment lines, highlighting the heavily pretreated nature of the study population. The clinical results showed a confirmed 45.9% objective response rate, with five patients achieving complete responses. The median duration of response reached 12.1 months, and 51% of responders remained in response at one year. The study also reported a median progression-free survival of 9.5 months. These findings are particularly relevant in platinum-resistant ovarian cancer, where treatment options can become increasingly limited following disease progression through multiple therapies. Importantly, antitumor activity was observed across different levels of FRα expression, including patients with low FRα expression and patients whose tumors did not express the target. Activity was also observed regardless of whether patients had previously received mirvetuximab, potentially broadening the population in which Rina-S could be investigated.

Genmab Advances FRα-Targeted ADC Development

Rinatabart sesutecan (Rina-S) is an investigational ADC designed to selectively target folate receptor alpha, a protein expressed on certain cancer cells. The molecule consists of a human monoclonal antibody directed against FRα, a hydrophilic protease-cleavable linker, and exatecan, a topoisomerase I (TOPO1) inhibitor payload. The ADC approach is intended to deliver a potent anticancer payload directly toward tumor cells expressing the target. Genmab is evaluating Rina-S across a broader clinical-development program covering gynecologic cancers and other solid tumors. The company’s development strategy includes four ongoing Phase 3 programs evaluating Rina-S in platinum-resistant ovarian cancer, recurrent or progressive endometrial cancer, platinum-sensitive ovarian cancer maintenance therapy, and second-line platinum-sensitive ovarian cancer. Additional Phase 2 studies are evaluating the candidate in non-small cell lung cancer and advanced gastrointestinal cancers. The latest Phase 2 findings therefore provide additional clinical evidence as Genmab advances the program into later-stage development. However, Rina-S remains investigational, and its safety and efficacy have not yet been established by regulatory authorities.

Rina-S Shows Manageable Safety Profile

The safety findings from the RAINFOL-01 Part C cohort showed that the most common treatment-emergent adverse events included fatigue, nausea, vomiting, constipation, decreased appetite and abdominal pain. Hematologic adverse events included anemia, neutropenia, decreased platelet count and thrombocytopenia. Serious adverse events were reported in approximately one-third of participants. Treatment discontinuation because of treatment-emergent adverse events occurred in 5.5% of participants.

Genmab reported that there were no safety signals for ocular toxicity, peripheral neuropathy, interstitial lung disease or stomatitis in the study. The company said the findings, including the observed response rate, duration of response and first progression-free survival data for the program, further inform the ongoing development of Rina-S. The results add to the growing clinical evidence for antibody-drug conjugates in ovarian cancer and support continued investigation of targeted approaches for patients with difficult-to-treat disease. Genmab’s ongoing Phase 3 studies will be important in determining whether the promising response and durability observed in the Phase 1/2 setting can be confirmed in larger, controlled clinical trials.

Source: Genmab press release