Mirvetuximab soravtansine-gynx (MIRV), a first-in-class antibody–drug conjugate targeting folate receptor α (FRα), showed benefits in phase 3 trial participants with platinum-resistant, FRα-positive ovarian cancer. Compared with chemotherapy, MIRV improved progression-free and overall survival and objective response.
The global, confirmatory, open-label, randomized, controlled trial enrolled participants had previously received 1 to 3 lines of therapy for platinum-resistant, high-grade serous ovarian cancer. They also had high FRα tumor expression (≥75% of cells with ≥2+ staining intensity). The effects of MIRV (6 mg/kg of adjusted ideal body weight every 3 weeks) or chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan) were assessed based on a primary endpoint of investigator-assessed progression-free survival.
“A total of 453 participants underwent randomization; 227 were assigned to the MIRV group and 226 to the chemotherapy group,” write the investigators. “The median progression-free survival was 5.62 months (95% confidence interval [CI], 4.34 to 5.95) with MIRV and 3.98 months (95% CI, 2.86 to 4.47) with chemotherapy (P <0.001). An objective response occurred in 42.3% of the participants in the MIRV group and in 15.9% of those in the chemotherapy group (odds ratio, 3.81; 95% CI, 2.44 to 5.94; P <0.001). Overall survival was significantly longer with MIRV than with chemotherapy (median, 16.46 months vs. 12.75 months; hazard ratio for death, 0.67; 95% CI, 0.50 to 0.89; P = 0.005). During the treatment period, fewer adverse events of grade 3 or higher occurred with MIRV than with chemotherapy (41.7% vs. 54.1%), as did serious adverse events of any grade (23.9% vs. 32.9%) and events leading to discontinuation (9.2% vs. 15.9%).”