Mirvetuximab Soravtansine-gynx Approved for FRα-Positive, Platinum-Resistant Epithelial Ovarian, Fallopian Tube, or Primary Peritoneal Cancer

Peritoneal fluid stain.

The FDA has approved mirvetuximab soravtansine-gynx (Elahere™, ImmunoGen, Inc.) for adult patients with folate receptor α (FRα)–positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. Patients are required to have received one to three prior systemic treatment regimens and are selected for treatment based on an FDA-approved test. Mirvetuximab soravtansine-gynx previously received accelerated approval for this indication in November 2022. 

Why it matters: “Mirvetuximab soravtansine, an antibody drug conjugate targeting FRα, demonstrated clinically meaningful antitumor activity in a single arm trial reported previously,” wrote Kathleen Moore, MD, MS, Associate Director of Clinical Research at the Stephenson Cancer Center, and colleagues, in their published results of the MIRASOL trial (NCT04209855), on which approval was based.

What they studied: Efficacy was measured in the phase 3, open-label trial which enrolled 453 patients with platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. Patients were randomized 1:1 to receive 6 mg/kg of mirvetuximab soravtansine-gynx as an intravenous infusion every three weeks or investigator’s choice of chemotherapy, which included paclitaxel, pegylated liposomal doxorubicin, or topotecan, until disease progression or unacceptable toxicity. Those enrolled were permitted to have received up to three prior lines of systemic therapy. The VENTANA FOLR1 (FOLR1-2.1) RxDx Assay was used to determine whether patients enrolled had tumors with a positive FRα expression.

The primary end points measured for approval were overall survival, investigator-assessed progression-free survival, and investigator-assessed confirmed overall response rate. Progression-free survival and overall response rate were evaluated according to RECIST v1.1.

What they found: Overall survival was seen at a median of 16.5 months in those receiving mirvetuximab soravtansine-gynx compared with a median of 12.7 months in those receiving chemotherapy. Median progression-free survival 5.6 months in the mirvetuximab soravtansine-gynx arm compared with 4.0 months in the chemotherapy arm. Overall response rate was 42% in those receiving mirvetuximab soravtansine-gynx and 16% in those receiving chemotherapy.

In addition, the previous accelerated approval for this indication’s post-marketing requirement was satisfied from the results of this trial.

Adverse events: The most common adverse events experienced in ≥20% of patients receiving mirvetuximab soravtansine-gynx, including laboratory abnormalities, were increased aspartate aminotransferase, fatigue, increased alanine aminotransferase, blurred vision, nausea, increased alkaline phosphatase, diarrhea, abdominal pain, keratopathy, peripheral neuropathy, musculoskeletal pain, decreased lymphocytes, decreased platelets, decreased magnesium, decreased hemoglobin, dry eye, constipation, decreased leukocytes, vomiting, decreased albumin, decreased appetite, and decreased neutrophils. Additionally, the prescribing information includes a Boxed Warning for ocular toxicity and Warnings and Precautions for pneumonitis, peripheral neuropathy, and embryo-fetal toxicity.

Conclusion: “Among participants with platinum-resistant, FRα-positive ovarian cancer, treatment with mirvetuximab soravtansine-gynx showed a significant benefit over chemotherapy with respect to progression-free, overall survival, and objective response,” concluded Dr. Moore and colleagues.

Instructions: The recommended dosage of mirvetuximab soravtansine-gynx is 6 mg/kg, based on adjusted ideal body weight, administered once every three weeks on a 21-day cycle as an intravenous infusion, until disease progression or unacceptable toxicity.

For More Information

Moore KN, Angelergues A, Konecny GE, et al (2023). Mirvetuximab soravtansine in FRα-positive, platinum-resistant ovarian cancer. N Engl J Med, 389(23):2162-2174. DOI:10.1056/NEJMoa2309169

Moore KN, Angelergues A, Konecny GE, et al (2023). Phase III MIRASOL (GOG 3045/ENGOT-ov55) study: Initial report of mirvetuximab soravtansine vs. investigator’s choice of chemotherapy in platinum-resistant, advanced high-grade epithelial ovarian, primary peritoneal, or fallopian tube cancers with high folate receptor-alpha expression. J Clin Oncol, 41(suppl_17). DOI:10.1200/JCO.2023.41.17_suppl.LBA5507

Clinicaltrials.gov (2024). A study of mirvetuximab soravtansine vs. investigator’s choice of chemotherapy in platinum-resistant, advanced high-grade epithelial ovarian, primary peritoneal, or fallopian tube cancers with high folate receptor-alpha expression (MIRASOL). NLM identifier: NCT04209855.

Elahere™ (mirvetuximab soravtansine-gynx) prescribing information (2024). ImmunoGen Inc. Available at: https://www.accessdata.fda.gov/drugsatfda_docs/label/2024/761310Origs005lbl.pdf

US Food and Drug Administration (2024). FDA approves mirvetuximab soravtansine-gynx for FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. Available at: https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-mirvetuximab-soravtansine-gynx-fra-positive-platinum-resistant-epithelial-ovarian

Image credit: Mikael Häggström, M.D. Licensed under CC0 1.0

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