Background: Elevated FRα expression is a characteristic of several solid tumors, including epithelial ovarian cancer (EOC), thereby providing an attractive candidate for targeted therapeutic approaches. Mirvetuximab soravtansine is an antibody-drug conjugate (ADC) comprising a FRα-binding antibody, cleavable linker, and the maytansinoid DM4, a potent tubulin-targeting agent that has shown consistent and meaningful single agent clinical activity, along with favorable tolerability, in patients with high FRα expressing tumors. Methods: MIRASOL is a randomized phase III study designed to evaluate the efficacy of mirvetuximab soravtansine compared with that of standard-of-care chemotherapy in adult patients with platinum-resistant EOC, primary peritoneal cancer, or fallopian tube cancer. Confirmation of high FRα positivity by immunohistochemistry (high expression; ≥ 75% of cells with PS2+ staining intensity) and ≤ 3 prior lines of therapy are required for inclusion. MIRASOL is designed to randomize 430 patients, 1:1 to Arm 1 (intravenous mirvetuximab soravtansine at a dose of 6 mg/kg, calculated using adjusted ideal body weight, on Day 1 of a 21-day cycle) or Arm 2 (investigators’ choice chemotherapy: paclitaxel, pegylated liposomal doxorubicin, or topotecan). The primary efficacy endpoint is progression-free survival (PFS; by investigator) and secondary endpoints include objective response rate, quality of life, overall survival, and safety and tolerability. MIRASOL opened for enrollment in December 2019. Clinical trial information: NCT04209855