FDA Grants Full Approval to Mirvetuximab Soravtansine for Pretreated Gynecologic Cancers

FDA Grants Full Approval to Mirvetuximab Soravtansine for Pretreated Gynecologic Cancers

The FDA granted full approval to mirvetuximab soravtansine-gynx (Elahere) for the treatment of adult patients with FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who were treated with 1 to 3 prior systemic treatment regimens.

An FDA-approved test would be used to determine whether patients are eligible for this treatment, according to an alert from the agency. The FDA previously granted mirvetuximab soravtansine accelerated approval in November 2022.

This approval is based on findings from the Study 0416/MIRASOL trial (NCT04209855). In this multicenter, open-label, active-controlled, randomized, two-arm trial, researchers analyzed data from 453 patients with platinum-resistant epithelial ovarian, primary peritoneal, or fallopian tube cancer who received up to 3 prior lines of systemic therapy. Patients in this trial had tumors that tested positive for FRα expression.

In a 1:1 fashion, patients were randomly assigned 6 mg/kg of mirvetuximab soravtansine (based on adjusted ideal body weight) delivered intravenously every 3 weeks or the investigator’s choice of chemotherapy (pegylated liposomal doxorubicin, paclitaxel, or topotecan). The assigned treatments are administered until unacceptable toxicity or disease progression.

The major efficacy outcome measures of the MIRASOL trial were investigator-assessed progression-free survival (PFS), overall survival (OS), and confirmed overall response rate (ORR) per investigator assessment. Of note, ORR and PFS were evaluated according to RECIST, version 1.1.

The median OS in the mirvetuximab soravtansine group was 16.5 months (95% CI, 14.5-24.6) compared with 12.7 months (95% CI, 10.9-14.4) in the chemotherapy group (HR = 0.67; 95% CI, 0.50-0.88; P = .0046). Median PFS was 5.6 months (95% CI, 4.3-5.96) in patients assigned mirvetuximab soravtansine vs 4.0 months (95% CI, 2.9-4.5) in patients assigned chemotherapy (HR = 0.65; 95% CI, 0.52-0.81; P < .0001). The ORR for the mirvetuximab soravtansine and chemotherapy groups was 42% (95% CI, 36%-49%) and 16% (95% CI, 12%-22%; P < .0001), respectively.

The prescribing information for mirvetuximab soravtansine has a Boxed Warning for ocular toxicity, according to the FDA. It also includes peripheral neuropathy, pneumonitis, and embryo-fetal toxicity under Warning and Precautions.

The most common adverse reactions, occurring in at least 20% of patients, included fatigue, increased aspartate aminotransferase levels, blurred vision, increased alanine aminotransferase levels, increased alkaline phosphatase levels, nausea, abdominal pain, diarrhea, peripheral neuropathy, keratopathy, decreased lymphocytes, musculoskeletal pain, decreased magnesium levels, decreased platelets, decreased hemoglobin, constipation, dry eye, vomiting, decreased leukocytes, decreased appetite, decreased albumin, and decreased neutrophils.

The FDA recommends that the dosing for mirvetuximab soravtansine is 6 mg/kg adjusted ideal body weight to be given as an intravenous infusion once every 3 weeks (21-day cycle) until unacceptable toxicity or disease progression.

Reference

FDA approves mirvetuximab soravtansine-gynx for FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. News release. FDA. March 22, 2024. Accessed March 22, 2024. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-mirvetuximab-soravtansine-gynx-fra-positive-platinum-resistant-epithelial-ovarian