On Aug. 26, 2025, Danish pharmaceutical company Genmab announced that Rinatabart Sesutecan (Rina-S), a novel therapy to treat recurrent and progressive endometrial cancer (EC), was granted Breakthrough Therapy Designation by the US Food and Drug Administration (FDA).
The decision was made based on positive results from the Phase 1/2 RAINFOL-01 clinical trial, which showed that patients with EC who were treated with Rina-S responded well to the treatment. The study, which included 64 patients with advanced EC, demonstrated that Rina-S promotes anti-tumor activity and may even lead to a complete response in some individuals.
Rina-S is an antibody-based drug that works by targeting cancer cells that overexpress folate receptor α (FRα). After binding to the receptor, the drug releases exatecan, a chemotherapy drug that interferes with DNA function, into the cell.
The drug is designed for patients with EC who had previously received a platinum-based chemotherapy or PD-L1 immunotherapy and experienced disease progression.
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“This Breakthrough Therapy Designation underscores the future potential of Rina-S as a treatment option for women diagnosed with advanced endometrial cancer, who face a poor prognosis after progressing on standard of care treatment,” said Dr. Judith Klimovsky, Executive Vice President and Chief Development Officer at Genmab.
Breakthrough Therapy Designation provides a number of benefits, including expedited drug review, in-depth guidance from experts and increased involvement from senior managers at FDA.
Currently, Genmab is investigating Rina-S in a Phase 3 clinical trial for ovarian cancer and is planning a Phase 3 trial for EC. Genmab is also organizing several clinical trials for other types of cancer.
If approved, Rina-S will be the first FRα-targeted therapy for patients with EC. Given that many tumor types overexpress this receptor, the technology may be adapted for a wide range of cancers in the future.
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