Nearly half of endometrial cancer patients respond to Rina-S in trial
Experimental treatment is also the focus of a pair of Phase 3 studies
Nearly half of women with hard-to-treat endometrial cancer responded to the investigational therapy Rina-S (rinatabart sesutecan) in a Phase 2 clinical trial, according to new data announced by Rina-S’s developer, Genmab.
“Women with advanced endometrial cancer are often facing a difficult path, while doctors are confronted with not having enough treatment options,” study investigator Noelle Cloven, MD, Texas Oncology Fort Worth and the Sarah Cannon Research Institute, said in a press release from Genmab. “That’s why these data signals with Rina-S in the updated Phase 1/2 RAINFOL-01 data are encouraging – they point to the possibility of providing more choices for patients in the future.”
3 patients had a complete response to therapy
Endometrial cancer is a form of gynecological cancer that develops due to the uncontrolled growth of cells in the lining of the uterus. While surgery is often the first-line treatment, chemotherapy and checkpoint inhibitors are used for advanced or recurrent disease. But when these fail, options are limited. Checkpoint inhibitors are medicines designed to make the immune system more efficiently attack cancer cells.
The new data come from a Phase 1/2 study called RAINFOL-01 (NCT05579366), which is testing Rina-S in people with various types of solid tumors. The new data specifically cover 64 patients with endometrial cancer whose cancer could not be removed with surgery or whose disease had progressed despite chemotherapy and checkpoint inhibitor treatment. Most of the patients had already received three or more previous lines of treatment. In the trial, these patients were given infusions of Rina-S every three weeks at one of two doses.
With a median follow-up time of about a year, results showed 50% of patients given a lower dose of Rina-S had a confirmed objective response, meaning the tumor got smaller following treatment. Among patients given the higher dose of Rina-S, the objective response rate was 44.1%.
With this updated data, we are seeing additional momentum behind the possibilities of Rina-S.
Three patients — two given the lower dose of Rina-S and one given the higher dose — had a complete response, basically meaning their cancer was no longer detectable after treatment.
Safety data from these patients showed the most commonly reported issues were low blood cell counts and digestive complaints. Serious safety problems were reported in 36.4% of patients given low-dose Rina-S and 52.4% given the high dose.
“With this updated data, we are seeing additional momentum behind the possibilities of Rina-S,” said Tahi Ahmadi, MD, executive vice president and chief medical officer, head of experimental medicines at Genmab.
Pair of Rina-S trials still recruiting participants
Rina-S contains a toxic molecule attached to an antibody that targets folate receptor alpha, a protein often expressed by certain cancer cells. This antibody-drug conjugate basically aims to use the antibody to deliver the toxin directly to cancer cells, thus killing the cancer cells while minimally impacting healthy cells in the body.
The RAINFOL-1 study is still recruiting participants at sites in the U.S. and China. Genmab is also running a Phase 3 study called RAINFOL-03 (NCT07166094), which seeks to enroll more than 500 people with endometrial cancer that has continued to progress after one to three prior lines of therapy, including chemotherapy and a checkpoint inhibitor.
Participants in the Phase 3 study will be randomly assigned to receive Rina-S or their doctor’s choice of standard-of-care therapies, with the main goal of seeing if Rina-S can extend the time patients spend alive without disease progression. The Phase 3 trial has not yet begun recruitment.
A different Phase 3 trial, RAINFOL-02 (NCT06619236), is testing Rina-S against standard-of-care therapy in people with ovarian cancer that is resistant to platinum-based chemotherapy. That trial is recruiting participants at sites in the U.S., including Puerto Rico, as well as in Japan and Canada.
The U.S. Food and Drug Administration recently granted Rina-S breakthrough therapy status as a potential treatment for endometrial cancer. This designation aims to speed the development of new therapies for serious diseases.
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