Mirvetuximab Soravtansine Granted Priority Review for Ovarian Cancer

The Food and Drug Administration (FDA) has accepted for Priority Review the Biologics License Application (BLA) for mirvetuximab soravtansine, for the treatment of patients with folate receptor alpha (FRα)-high platinum-resistant ovarian cancer who have been previously treated with 1 to 3 prior systemic treatments. A decision on the application is expected on November 28, 2022.

Mirvetuximab soravtansine is an antibody-drug conjugate comprised of a FRα-binding antibody, a cleavable linker, and a potent tubulin-targeting agent (maytansinoid payload DM4). The application includes data from the phase 3 SORAYA trial (ClinicalTrials.gov Identifer: NCT04296890), which investigated the treatment in patients with FRα-high platinum-resistant ovarian cancer who had been previously treated with bevacizumab (N=106). All patients received mirvetuximab soravtansine monotherapy administered on day 1 of every 3 week cycle.

Results showed a confirmed objective response rate (ORR; primary endpoint) of 32.4% (95% CI, 23.6-42.2), including 5 complete responses, as assessed by the investigator. When assessed by blinded independent central review, the ORR was 31.6% (95% CI, 22.4-41.9). Responses were also observed to be consistent regardless of the number of prior lines of therapy or prior PARP inhibitor use.

Median duration of response (secondary endpoint) was 6.9 months (95% CI, 5.6-8.1). The most common treatment-related adverse events were blurred vision, keratopathy, and nausea.

ImmunoGen is seeking approval of mirvetuximab soravtansine under the FDA’s accelerated approval pathway, which allows for expedited review based on a surrogate endpoint. The Company has already begun enrolling patients in the MIRASOL study (ClinicalTrials.gov Identifier: NCT04209855), a confirmatory trial that is intended to convert the accelerated approval to full approval; topline data from this trial are expected in early 2023.

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