In addition to the drug approval, the FDA approved a companion diagnostic to be used to identify patients who are eligible to receive the treatment.
The FDA granted mirvetuximab soravtansine-gynx (Elahere, ImmunoGen) accelerated approval for adults with folate receptor α (FRα)–positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer for patients who have received 1 to 3 previous systemic treatment regimens.
The therapy is a folate receptor α–directed antibody and microtubule inhibitor conjugate. It is the first antibody drug conjugate approved for platinum-resistant disease.
"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," Ursula Matulonis, MD, chief of the Division of Gynecologic Oncology at the Dana-Farber Cancer Institute, professor of medicine at the Harvard Medical School, and co-principal investigator of the pivotal trial SORAYA, said in a statement. “Elahere’s impressive anti-tumor activity, durability of response, and overall tolerability observed in SORAYA demonstrate the benefit of this new therapeutic option, and I look forward to treating patients with Elahere."
The FDA also approved the VENTANA FOLR1 (FOLR-2.1) RxDx Assay as a companion diagnostic to determine which patients are eligible for mirvetuximab soravtansine-gynx.
The therapy was approved based on results from the SOYAYA study (also known as Study 0417), a single-arm trial of 106 patients. All of the patients had received bevacizumab as one of their previous regimens; however, the approval is for patients regardless of prior bevacizumab use. Patients were confirmed to have FRα-positive tumors using FOLR-2.1.
Patients received 6 mg/kg (adjusted for ideal body weight) intravenously once every 3 weeks. In the study, the objective response rate was 31.7% (95% CI: 22.9%-41.6%) and the median duration of response was 6.9 months (95% CI: 5.6-9.7). Five of the patients had a complete response.
The most common adverse events were vision impairment, fatigue, increased aspartate aminotransferase, nausea, increased alanine aminotransferase, keratopathy, abdominal pain, decreased lymphocytes, peripheral neuropathy, diarrhea, decreased albumin, constipation, increased alkaline phosphatase, dry eye, decreased magnesium, decreased leukocytes, decreased neutrophils, and decreased hemoglobin.
Since mirvetuximab soravtansine-gynx was granted accelerated approval, continued approval may be contingent on verification and description of benefit in a confirmatory trial. Data from the confirmatory trial MIRASOL is expected in early 2023.
"Platinum-resistant ovarian cancer is a notoriously challenging disease to treat, said Anna Berkenbilt, MD, senior vice president and chief medical officer of ImmunoGen. “Given there have been no new therapies approved by FDA for this indication since 2014, Elahere’s accelerated approval is a tremendous advance in the ovarian cancer treatment paradigm.”