On November 14, 2022, the FDA accelerated the approval of mirvetuximab soravtansine-gynx (Elahere; ImmunoGen), an intravenous folate receptor alpha (FRα)-directed antibody and microtubule inhibitor conjugate, for the treatment of adults with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer after 1 to 3 previous systemic treatments, regardless of previous use of bevacizumab. Patients should be identified for treatment with mirvetuximab soravtansine by an FDA-approved test.
Mirvetuximab soravtansine is the first FRα-directed antibody–drug conjugate approved by the FDA.
On the same day, the FDA approved the VENTANA FOLR1 RxDx Assay, a companion diagnostic test to mirvetuximab soravtansine.
“The approval of Elahere is significant for patients with FRα-positive platinum-resistant ovarian cancer, which is characterized by limited treatment options and poor outcomes,” said Ursula Matulonis, MD, Chief, Division of Gynecologic Oncology, Dana-Farber Cancer Institute, Boston, and co-principal investigator of the SORAYA study. “Elahere’s impressive anti-tumor activity, durability of response, and overall tolerability observed in SORAYA demonstrate the benefit of this new therapeutic option.”
The efficacy of mirvetuximab soravtansine was evaluated in the SORAYA study, a single-arm clinical trial of 106 patients with FRα-positive, platinum-resistant epithelial ovarian cancer. The drug’s safety was evaluated in a pooled analysis of 3 studies that included 464 patients with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer.
Patients were allowed to have up to 3 previous lines of systemic therapy, regardless of bevacizumab use. Patients with FRα-positive disease were identified by the VENTANA FOLR1 RxDx Assay. Patients were excluded from the study if they had corneal disorders, ocular conditions requiring ongoing treatment, grade >1 peripheral neuropathy, or noninfectious interstitial lung disease.
All patients received mirvetuximab soravtansine 6 mg/kg (based on adjusted ideal body weight) as an intravenous (IV) infusion every 3 weeks, until disease progression or unacceptable adverse events. Response to therapy was evaluated every 6 weeks for the first 36 weeks, and every 12 weeks thereafter.
The main efficacy measures were overall response rate (ORR) and duration of response (DOR). Among the 104 patients with platinum-resistant disease who received ≥1 doses of mirvetuximab soravtansine, the ORR was 31.7% (95% confidence interval [CI], 22.9-41.6), including 5 complete responses, and the median DOR was 6.9 months (95% CI, 5.6-9.7).
The most common (≥20%) adverse events with mirvetuximab soravtansine were vision impairment, dry eye, fatigue, increased aspartate aminotransferase, nausea, increased alanine aminotransferase, keratopathy, abdominal pain, decreased lymphocytes, peripheral neuropathy, diarrhea, decreased albumin, constipation, increased alkaline phosphatase, decreased magnesium, decreased leukocytes, decreased neutrophils, and decreased hemoglobin.
The prescribing information for mirvetuximab soravtansine includes a boxed warning for ocular adverse events, including visual impairment, keratopathy, dry eye, photophobia, eye pain, and uveitis.
The recommended dose of mirvetuximab soravtansine is 6 mg/kg once every 3 weeks as an IV infusion until disease progression or unacceptable adverse events.