Full Approval Granted to Antibody-drug Conjugate for Gynecologic Cancers
Mirvetuximab soravtansine-gynx was approved for certain ovarian, fallopian tube, and peritoneal cancers.
The U.S. Food and Drug Administration (FDA) has approved mirvetuximab soravtansine-gynx (Elaher) for patients with ovarian epithelial, fallopian tube, or peritoneal cancers who have received one to three prior systemic therapies and whose tumors have elevated expression of the folate receptor alpha (FRα) and are resistant to platinum chemotherapy.
It was previously granted accelerated approval for this indication in November 2022.
An antibody-drug conjugate, a type of targeted cancer therapy that facilitates the delivery of toxic drugs to cells that express a target protein, mirvetuximab soravtansine-gynx selectively delivers the cell-killing drug DM4 to cells that express FRα. Since normal cells have limited expression of FRα, mirvetuximab soravtansine-gynx primarily affects cancer cells.
The conversion from an accelerated approval to a full approval was based on results from MIRASOL, a multicenter, open-label, active-controlled, randomized, two-arm phase III clinical trial. The trial enrolled 453 patients with platinum-resistant, FRα-positive ovarian, fallopian tube, or peritoneal cancer who had received no more than three prior lines of systemic therapy. Patients were randomly assigned (1:1) to receive either mirvetuximab soravtansine-gynx or chemotherapy (investigator’s choice of paclitaxel, pegylated liposomal doxorubicin, or topotecan).
Compared with patients treated with chemotherapy, those treated with mirvetuximab soravtansine-gynx had significantly longer overall survival (12.7 months vs. 16.5 months, respectively) and significantly longer progression-free survival (4.0 months vs. 5.6 months, respectively). In addition, 42% of patients responded to mirvetuximab soravtansine-gynx treatment, as compared with 16% who responded to chemotherapy.
The recommended dosage is 6 mg/kg of adjusted ideal body weight delivered intravenously once every three weeks until disease progression or unacceptable toxicity occurs. The prescribing information includes a boxed warning for ocular toxicity.
Cancers of the ovary, fallopian tube, and peritoneum (the tissue that covers the abdominal wall) form in the epithelial cells lining these areas. Since these cancers form in the same type of tissue, they are treated similarly. According to federal statistics, it was estimated that 19,680 individuals would be diagnosed with ovarian cancer and 12,740 patients would die of the disease in the United States in 2024.
The FDA rendered its decision on March 22, 2024.
