Mirvetuximab Soravtansine Improved Survival, Response Among Patients With Platinum-Resistant, FRα-Positive Ovarian Cancer

According to results from the phase 3 MIRASOL trial, mirvetuximab soravtansine, a first-in-class antibody-drug conjugate targeting folate receptor α (FRα), significantly improved progression-free survival (PFS), overall survival (OS), and objective response among patients with platinum-resistant, FRα-positive ovarian cancer, compared with chemotherapy. 

In this confirmatory, open-label trial, 453 patients with platinum-resistant, high-grade serous ovarian cancer previously treated with 1 to 3 lines of therapy and high FRα expression were randomized on a 1-to-1 basis to receive either 6 mg/kg (of adjusted ideal body weight) mirvetuximab soravtansine every 3 weeks (n = 227) or investigator’s choice chemotherapy (n = 226). The primary end point was investigator-assessed PFS. Secondary end points included objective response and OS. 

Median PFS was 5.62 months in the mirvetuximab soravtansine arm and 3.98 months in the chemotherapy arm (P < .001). Objective response occurred in 42.3% of patients in the mirvetuximab soravtansine arm and 15.9% of patients in the chemotherapy arm (odds ratio, 3.81; 95% confidence interval [CI], 2.44 to 5.94; P < .001). Median OS was 16.46 months in the mirvetuximab soravtansine arm and 12.75 months in the chemotherapy arm (hazard ratio [HR] for death, 0.67; 95% CI, 0.50 to 0.89; P = .005). Adverse events occurred in 41.7% of patients in the mirvetuximab soravtansine arm and 54.1% of patients in the chemotherapy arm. Serious adverse events of any grade occurred in 23.9% of patients in the mirvetuximab soravtansine arm and 32.9% of patients in the chemotherapy arm. Events leading to treatment discontinuation occurred in 9.2% and 15.9% of patients, respectively. 

Study authors concluded “treatment with [mirvetuximab soravtansine] showed a significant benefit over chemotherapy with respect to progression-free and overall survival and objective response.”

Source:

Moore KN, Angelergues A, Konecny GE, et al. Mirvetuximab soravtansine in FRα-positive, platinum-resistant ovarian cancer. N Eng J Med. Published online: December 7, 2023. doi:10.1056/NEJMoa2309169