MIRASOL: OS Benefit for Mirvetuximab in Platinum-Resistant Ovarian Cancer
Toon Van Gorp, MD, PhD, discusses the rationale behind and the findings from the phase 3 MIRASOL trial of mirvetuximab soravtansine in patients with folate receptor α–positive, platinum-resistant ovarian cancer.
Toon Van Gorp, MD, PhD, University Hospital Leuven Kefir Cancer Institute and BGOG, in Leuven, Belgium, discusses the rationale behind the phase 3 MIRASOL trial (NCT04209855) of mirvetuximab soravtansine-gynx (Elahere) vs investigator’s choice of chemotherapy (ICC) in patients with folate receptor α (FRα)–positive, platinum-resistant ovarian cancer, and the key findings from a recent final analysis that was presented at the 2025 Society of Gynecologic Oncology Annual Meeting on Women’s Cancer (SGO).
“The MIRASOL study was a randomized trial, an open-label, phase 3 trial, which randomized patients between mirvetuximab soravtansine and investigator’s choice chemotherapy. In total, we randomized 453 patients, 1:1,” explains Van Gorp.
The study’s primary end point was progression-free survival by the investigator, and secondary end points included objective response rate, overall survival, and patient-reported outcomes.
According to findings from the primary analysis and a follow-up time of 13.1 months, positive results in favor of mirvetuximab for progression-free survival, overall survival, and objective response rate were observed. Now, with longer follow-up, which was 30.5 months, treatment with mirvetuximab (n = 227) led to a median OS of 16.85 months (95% CI, 14.36-19.78) vs 13.34 months (95% CI, 11.37-15.15) with ICC (n = 226), representing a 32% reduction in the risk of death (HR, 0.68; 95% CI, 0.54-0.84; P =.0004). OS benefits were consistent across key subgroups, regardless of prior bevacizumab (Avastin) or PARP inhibitor use, number of prior therapies, or type of chemotherapy.
“What we saw was that the results reinforced the protection of mirvetuximab. We had a positive result for overall survival: the median overall survival was 16.9 months for mirvetuximab, and it was 13.3 months for investigator’s choice chemotherapy. This gave a hazard ratio of 0.68, so a reduction of 32% in the risk of death due to the disease,” says Van Gorp.
