Is Mirvetuximab Soravtansine Better Than Chemotherapy in FRα-Expressing Recurrent Ovarian Cancer?

In November 2023, the FDA granted accelerated approval to mirvetuximab soravtansine-gynx (MIRV), an antibody–drug conjugate that targets folate receptor alpha (FRα), based on the positive results of the single-arm SORAYA trial of MIRV in Fra-high, platinum-resistant ovarian cancer (J Clin Oncol 2023; 41:2436).

Now, investigators report the industry-sponsored, global, open-label phase 3 MIRASOL study, in which 453 patients were randomized to either investigator's choice of chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan) or MIRV (6 mg/kg every 3 weeks). Eligible patients had platinum-resistant disease, had received 1 to 3 lines of prior systemic therapy, and had high FRα tumor expression by immunohistochemical staining (by the FDA-approved VENTANA FOLR1 [FOLR1-2.1] RxDx assay).

Median progression-free survival, the primary outcome, was significantly longer in the MIRV arm than the chemotherapy arm (5.62 vs. 3.98 months). Median overall survival was also significantly longer in the MIRV arm than in the chemotherapy arm (16.46 vs. 12.75 months; hazard ratio for death, 0.67; P=0.005).

In the MIRV arm, grade 3 ocular events occurred in 44 participants, and nearly all resolved to grade 0 or 1; four participants (1.8%) discontinued MIRV due to ocular toxicities. Overall, 9.2% of patients in the MIRV arm and 15.9% in the chemotherapy arm stopped treatment due to toxicity. Grade 3 or higher adverse events were less frequent with MIRV than with chemotherapy (41.7% vs. 54.1%).