Eli Lilly and Company (NYSE: LLY) today announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation to sofetabart mipitecan (LY4170156) for the treatment of adult patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have received prior bevacizumab and mirvetuximab soravtansine, if eligible. Sofetabart mipitecan is a novel folate receptor alpha (FRα) antibody-drug conjugate (ADC) that uses proprietary linker technology and an exatecan payload. 

Breakthrough Therapy designation aims to expedite the development and review of drugs that are intended to treat a serious condition and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over available therapy on a clinically significant endpoint(s).

“Platinum-resistant ovarian cancer remains one of the most challenging settings in gynecologic oncology, with limited treatment options and poor outcomes for patients,” said Bhavana Pothuri, M.D., 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. “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.”

“We are pleased the FDA has granted Breakthrough Therapy designation for sofetabart mipitecan, reflecting the significant unmet need in platinum-resistant ovarian cancer and the promising initial results shown in our Phase 1 study,” said Jacob Van Naarden, executive vice president, and president of Lilly Oncology and head of corporate business development. “Building on compelling results generated to date, we’ve initiated our Phase 3 FRAmework-01 trial with the goal of bringing a potential therapeutic option to patients with advanced ovarian cancer, across all levels of folate receptor expression.”

The FDA Breakthrough Therapy designation is based on encouraging preliminary results from the Phase 1a/b study. Lilly presented initial Phase 1 results at the 2025 ASCO Annual Meeting in June and updated data at the 2025 ESMO Congress in October, showing responses at all dose levels and across all FRα expression levels, including in patients who progressed on prior mirvetuximab soravtansine. These initial data also indicate a promising tolerability profile with low rates of interstitial lung disease, peripheral neuropathy, and alopecia, and no significant ocular toxicity.

Sofetabart mipitecan recently advanced into the Phase 3 FRAmework-01 study (NCT07213804), a global trial investigating the treatment as a monotherapy in patients with platinum resistant ovarian cancer (PROC), and in combination with bevacizumab in patients with platinum-sensitive ovarian cancer (PSOC). Lilly is conducting the FRAmework-01 study in partnership with the European Network for Gynaecological Oncological Trial groups (ENGOT – lead groups GINECO/NOGGO e.V.), the GOG Foundation (GOG), and the Asia-Pacific Gynecologic Oncology Trials Group (APGOT)