Dr Moore on the 2024 FDA Approval of Mirvetuximab Soravtansine in Ovarian Cancer

“We had the accelerated approval [of mirvetuximab soravtansine] in the United States [prior to the full approval], but now full approval [is] based on [the] MIRASOL [data, which] proved [that] mirvetuximab [soravtansine] is a highly efficacious medication and superior to standard of care options.”

Kathleen N. Moore, MD, MS, associate director, clinical research, Stephenson Cancer Center, director, Oklahoma TSET Phase I Program, professor, Section of Gynecologic Oncology, Oklahoma University (OU) College of Medicine, OU Health, details the implications of the full FDA approval of mirvetuximab soravtansine-gynx (Elahere) in ovarian cancer.

In March 2024, the FDA granted regular approval of the antibody-drug conjugate (ADC) mirvetuximab soravtansine for the treatment of patients with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who were previously received 1 to 3 systemic treatment regimens. The approval was based on data from the phase 3 MIRASOL trial (NCT04209855), Moore begins. She explains that in the study, mirvetuximab soravtansine demonstrated superiority to standard-of-care options, and the phase 3 study met its primary end point of progression-free survival (PFS).

Of note, FRα is a cell surface folate receptor that mediates folate transport into epithelial cells, according to Moore’s presentation at the 2025 Society of Gynecologic Oncology Winter Meeting. Although FRα expression is limited on normal cells, it’s upregulated primarily on ovarian, endometrial, and triple-negative breast cancers. Assessed by immunohistochemistry, FRα is most highly expressed on the surface of serous epithelial ovarian cancers. Its expression varies by histology, of which 76% is high-grade serous, 50% is low-grade serous, and 32% is clear cell.

Moore also notes that data from the phase 3 FORWARD I trial (NCT02631876) showed signs of overall survival benefits, specifically in patients with FRα–high disease. She emphasizes that this was an exploratory look at a negative trial, where positive exploratory end points often do not materialize. However, when the exploratory end points were formally studied, the end points materialized, she concludes.