FDA Approves Mirvetuximab Soravtansine for Folate Receptor Alpha–Positive Ovarian Cancer

M. Alexander Otto, PA, MMS

November 15, 2022

The US Food and Drug Administration (FDA) has granted accelerated approval to mirvetuximab soravtansine (Elahere) for use in pretreated patients with folate receptor (FR) alpha–positive, platinum-resistant epithelial ovarian, fallopian tube, and primary peritoneal cancer. These patients can have received one to three prior lines of treatment.

"Continued approval may be contingent upon verification and description of clinical benefit in a confirmatory trial," according to labeling.

Mirvetuximab soravtansine is an antibody-drug conjugate (ADC) with an antibody directed against FR alpha that is linked to a microtubule inhibitor conjugate.

This product is a first-in-class ADC directed against FR alpha, a cell-surface protein highly expressed in ovarian cancer, and is the first FDA-approved ADC for platinum-resistant disease, said the manufacturer, ImmunoGen.

Patients are selected for treatment with this drug using a diagnostic test that the FDA approved along with the agent: the VENTANA FOLR1 (FOLR-2.1) RxDx Assay.

FR alpha–positive platinum-resistant ovarian cancer is characterized by limited treatment options and poor outcomes, commented Ursula Matulonis, MD, chief of the division of gynecologic oncology at the Dana-Farber Cancer Institute and co–principal investigator of the SORAYA trial that led to the approval. In a company press release, she said results from this trial show that mirvetuximab soravtansine has "impressive anti-tumor activity, durability of response, and overall tolerability…[which] demonstrate the benefit of this new therapeutic option."

Accelerated Approval Based on Response Data

The SORAYA trial (also known as Study 0417 [NCT04296890]) was a single-arm trial of 106 patients with FR alpha–positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer.

These patients were identified as FR alpha–positive by using the assay. They were permitted to receive up to three prior lines of systemic therapy, and all patients were required to have received bevacizumab.

All patients received mirvetuximab soravtansine-gynx 6 mg/kg (based on adjusted ideal body weight) as an intravenous infusion every 3 weeks until disease progression or unacceptable toxicity.

The approval was based on an investigator-assessed overall response rate of 31.7%, which included five complete responses, and a median duration of response of 6.9 months.

Safety was evaluated in a pooled analysis from three studies among a total of 464 patients with FR alpha–positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who received at least one dose of the drug.

The most common adverse events, occurring in 20% or more of study participants, were vision impairment, fatigue, increased aspartate aminotransferase level, nausea, increased alanine aminotransferase level, keratopathy, abdominal pain, decreased lymphocytes, peripheral neuropathy, diarrhea, decreased albumin, constipation, increased alkaline phosphatase level, dry eye, decreased magnesium level, decreased leukocyte count, decreased neutrophil count, and decreased hemoglobin level.

Potential participants were excluded if they had corneal disorders, ocular conditions requiring ongoing treatment, peripheral neuropathy above grade 1, or noninfectious interstitial lung disease.

The product labeling contains a boxed warning of ocular toxicity. Full prescribing information is available.

M. Alexander Otto is a physician assistant with a master's degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape. Alex is also an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com

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