FDA OKs Breakthrough Status for Sofetabart Mipitecan for Some Gynecologic Cancers

The U.S. Food and Drug Administration (FDA) has granted breakthrough therapy designation to sofetabart mipitecan for adult patients with platinum-resistant epithelial ovarian, fallopian tube or primary peritoneal cancer who previously received bevacizumab and mirvetuximab soravtansine, Eli Lilly and Company announced in a news release, based on early clinical data showing responses across all levels of folate receptor alpha expression.

The designation is intended to help speed the development and review of treatments for serious conditions when preliminary clinical evidence suggests meaningful improvement over available therapies, according to the FDA.

Main data that support the findings of sofetabart mipitecan

The breakthrough therapy designation was based on preliminary results from a phase 1a/b study of sofetabart mipitecan. Initial data were presented at the 2025 ASCO Annual Meeting in June, with updated results shared at the 2025 ESMO Congress in October.

According to Lilly, the early findings showed tumor responses at all dose levels studied and across all levels of folate receptor alpha expression. Responses were also observed in patients whose cancer had progressed following prior treatment with Elahere (mirvetuximab soravtansine).

Investigators reported that the initial data suggested a promising tolerability profile. Low rates of interstitial lung disease, peripheral neuropathy and alopecia were observed. No significant ocular toxicity was reported in the study population.

"Platinum-resistant ovarian cancer remains one of the most challenging settings in gynecologic oncology, with limited treatment options and poor outcomes for patients," Dr. Bhavana Pothuri, professor of Obstetrics/Gynecology and Medicine at NYU Grossman School of Medicine, NYU Langone Health and director of Clinical Trials Office at the Perlmutter Cancer Center, said in the news release. "The breakthrough therapy designation and preliminary clinical data for sofetabart mipitecan across all levels of FRα expression are encouraging and point to its potential as a meaningful treatment option for patients."

Trial details

Sofetabart mipitecan is a folate receptor alpha antibody-drug conjugate that uses a proprietary linker technology and an exatecan payload. The treatment was designed to target folate receptor alpha across all expression levels.

Following the phase 1 findings, sofetabart mipitecan has advanced into the phase 3 FRAmework-01 study. The global trial is evaluating the treatment in two settings. One cohort is studying sofetabart mipitecan as a monotherapy in patients with platinum-resistant ovarian cancer. Another cohort is evaluating the treatment in combination with Avastin (bevacizumab) in patients with platinum-sensitive ovarian cancer.

The FRAmework-01 study is being conducted in partnership with multiple international research groups, including the European Network for Gynaecological Oncological Trial groups, the GOG Foundation and the Asia-Pacific Gynecologic Oncology Trials Group.

Lilly stated that the phase 3 program aims to study the treatment across all levels of folate receptor expression in patients with advanced ovarian cancer.

Safety of sofetabart mipitecan

Safety observations from the phase 1a/b study indicated that sofetabart mipitecan had a favorable tolerability profile in the patients treated to date, according to the company.

Low rates of interstitial lung disease, peripheral neuropathy and alopecia were reported in the early analysis. Investigators also reported no significant ocular toxicity, an important consideration for treatments targeting folate receptor alpha.

Lilly noted that the findings are based on preliminary data and that ongoing and future studies will further evaluate both the safety and effectiveness of sofetabart mipitecan in larger patient populations.

Reference

1. “Lilly's sofetabart mipitecan receives U.S. FDA's Breakthrough Therapy designation for the treatment of certain patients with platinum-resistant ovarian cancer.” News Release. Eli Lilly and Company. Jan 20, 2026.

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