November 2022: For adult patients who have had one to three prior systemic treatment regimens and have folate receptor alpha (FR) positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, the Food and Drug Administration has given accelerated approval to mirvetuximab soravtansine-gynx (Elahere, ImmunoGen, Inc.). A microtubule inhibitor and folate receptor alpha directed antibody are combined in mirvetuximab soravtansine-gynx. A FDA-approved test is used to determine which patients will receive treatment.
The VENTANA FOLR1 (FOLR-2.1) RxDx Assay (Ventana Medical Systems, Inc.) was just given FDA approval as a companion diagnostic tool for the aforementioned indication.
Study 0417 (NCT04296890), a single-arm trial involving 106 patients with FR-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, assessed the effectiveness of treatment. Up to three preceding lines of systemic therapy were allowed for patients. Bevacizumab was a need for all patients. Patients whose tumours tested positive for FR expression using the aforementioned assay were included in the study. Patients were disqualified if they had noninfectious interstitial lung disease, Grade >1 peripheral neuropathy, corneal problems, or ocular illnesses that required continuous care.
Patients received an intravenous infusion of mirvetuximab soravtansine-gynx 6 mg/kg (based on adjusted ideal body weight) every three weeks until their condition progressed or the side effects became intolerable. Every six weeks during the first 36 weeks, and then every 12 weeks after that, tumour response evaluations were conducted.
Overall response rate (ORR) and duration of response (DOR) as determined by the investigator and measured in accordance with RECIST version 1.1 were the primary efficacy outcome measures. The confirmed ORR was 31.7% (95% CI: 22.9, 41.6) and the median DOR was 6.9 months (95% CI: 5.6, 9.7) in the efficacy evaluable sample of patients who had platinum resistant, quantifiable illness and received at least one dose (104 patients).
Vision impairment, fatigue, increased aspartate aminotransferase, nausea, increased alanine aminotransferase, keratopathy, abdominal pain, decreased lymphocytes, peripheral neuropathy, diarrhoea, decreased albumin, constipation, increased alkaline phosphatase, dry eye, decreased magnesium, decreased leukocytes, decreased neutrophils, and decreased haemoglobin were the most common (20%) adverse reactions, including laboratory abnormalities. There is a boxed warning for eye toxicity on the product label.
The suggested dose of mirvetuximab soravtansine-gynx is 6 mg/kg adjusted ideal body weight (AIBW), given intravenously once every 21 days (cycle) until disease progression or intolerable toxicity.