On 22 March 2024, the US Food and Drug Administration (FDA) approved mirvetuximab soravtansine-gynx (Elahere, ImmunoGen, Inc. [now a part of AbbVie]) for adult patients with FRα-positive, platinum-resistant epithelial ovarian, Fallopian tube, or primary peritoneal cancer, who have received one to three prior systemic treatment regimens. Patients are selected based on an FDA-approved test. Mirvetuximab soravtansine-gynx previously received accelerated approval for this indication.
Efficacy was evaluated in Study 0416 (MIRASOL, NCT04209855), a multicentre, open-label, active-controlled, randomised, two-arm study in 453 patients with platinum-resistant epithelial ovarian, Fallopian tube, or primary peritoneal cancer. Patients were permitted to receive up to three prior lines of systemic therapy. The study enrolled patients whose tumours were positive for FRα expression as determined by the VENTANA FOLR1 (FOLR1-2.1) RxDx Assay. Patients were randomised (1:1) to receive mirvetuximab soravtansine-gynx 6 mg/kg (based on adjusted ideal body weight) as an intravenous infusion every 3 weeks or investigator’s choice of chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan) until disease progression or unacceptable toxicity. The results from this study satisfy the post-marketing requirement of the previous accelerated approval for mirvetuximab soravtansine-gynx.
The major efficacy outcome measures were overall survival (OS), investigator-assessed progression-free survival (PFS) and confirmed overall response rate (ORR) per investigator assessment. PFS and ORR were evaluated according to RECIST v1.1. Median OS was 16.5 months (95% confidence interval [CI] 14.5, 24.6) in the mirvetuximab soravtansine-gynx arm and 12.7 months (95% CI 10.9, 14.4) in the chemotherapy arm (hazard ratio [HR] 0.67, 95% CI 0.50, 0.88; p-value = 0.0046). Median PFS was 5.6 months (95% CI 4.3, 5.9) and 4.0 months (95% CI 2.9, 4.5) (HR 0.65, 95% CI 0.52, 0.81; p-value <0.0001) for the respective arms. ORR was 42% (95% CI 36, 49) and 16% (95% CI 12, 22) (p-value <0.0001), respectively.
The prescribing information contains a Boxed Warning for ocular toxicity, and includes pneumonitis, peripheral neuropathy, and embryo-foetal toxicity under Warnings and Precautions. The most common adverse reactions (≥ 20%) including laboratory abnormalities were increased aspartate aminotransferase, fatigue, increased alanine aminotransferase, blurred vision, nausea, increased alkaline phosphatase, diarrhoea, abdominal pain, keratopathy, peripheral neuropathy, musculoskeletal pain, decreased lymphocytes, decreased platelets, decreased magnesium, decreased haemoglobin, dry eye, constipation, decreased leukocytes, vomiting, decreased albumin, decreased appetite, and decreased neutrophils.
The recommended mirvetuximab soravtansine-gynx dose is 6 mg/kg adjusted ideal body weight administered once every 3 weeks (21-day cycle) as an intravenous infusion until disease progression or unacceptable toxicity.
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