The Food and Drug Administration (FDA) has granted accelerated approval to mirvetuximab soravtansine-gynx (Elahere) for the treatment of adult patients with folate receptor [alpha] (FR[alpha])-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received one to three prior systemic treatment regimens. Accelerated approval means approval was granted based on a surrogate end point or marker that is believed to predict clinical benefit.

Ovarian cancer is the fifth leading cause of cancer deaths among women1 and epithelial ovarian cancer accounts for 90% of ovarian cancers.2 Fallopian tube cancer may account for up to 70% of all epithelial ovarian cancers. Most cancers in the ovaries, fallopian tubes, and peritoneum are grouped together for diagnosis, treatment, and management.3 Primary peritoneal cancer is idiopathic. Its subtype resembles serous ovarian carcinoma and occurs exclusively in women.4

Mirvetuximab soravtansine-gynx is a FR[alpha]-directed antibody and microtubule inhibitor conjugate. FR[alpha] is a protein highly expressed in ovarian cancer and covalently linked to the microtubule inhibitor DM4, which causes cell cycle arrest and apoptosis. Patients are selected for therapy based on an FDA-approved test.

Accelerated approval of mirvetuximab soravtansine-gynx was based on a single-arm trial of 106 patients with FR[alpha]-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. Patients were permitted to receive up to three prior lines of systemic therapy. All patients were required to have received the antiangiogenic agent bevacizumab. The trial enrolled patients whose tumors were positive for FR[alpha] expression as determined by the FDA-approved assay. Patients received mirvetuximab soravtansine-gynx intravenously every three weeks until disease progression or unacceptable toxicity. The overall response rate was 31.7%, but only 4.8% were complete responses. The median duration of response was 6.9 months. In another open-label trial, 366 patients with FR[alpha]-positive, platinum-resistant epithelial ovarian cancer were randomized to receive mirvetuximab soravtansine-gynx or chemotherapy. The primary end point, progression-free survival, was similar in both groups, but the objective response rate was higher for those in the mirvetuximab soravtansine-gynx group than the chemotherapy group (24% versus 10%).

Mirvetuximab soravtansine-gynx's labeling has a boxed warning for ocular toxicity. Other warnings include the risk of pneumonitis (which occurred in 10% of patients and can be severe, life threatening, or fatal), peripheral neuropathy (which occurred in 36% of patients with ovarian cancer treated across clinical trials), and embryo-fetal toxicity. The most common adverse effects were laboratory abnormalities (increased aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase; decreased albumin, magnesium, lymphocytes, leukocytes, neutrophils, and hemoglobin); eye problems (vision impairment, keratopathy, and dry eye); gastrointestinal problems (nausea, abdominal pain, diarrhea, and constipation); peripheral neuropathy; and fatigue.

Nurses and NPs should conduct an ophthalmic examination or confirm one was conducted prior to initiation of mirvetuximab soravtansine-gynx and before every other cycle for the first eight cycles and then as clinically indicated. If ocular toxicities are present, the drug should be withheld until improvement. If there are grade 4 ocular toxicities, the drug should be discontinued. Prior to treatment, nurses should administer prophylactic artificial tears and ophthalmic topical steroids. Other premedication includes an IV corticosteroid, an oral or IV antihistamine, an oral or IV antipyretic, and an oral or IV antiemetic to prevent infusion-related reactions, nausea, and vomiting.

Nurses should obtain the patient's accurate weight before drug administration as the dose is weight based. For complete prescribing information for mirvetuximab soravtansine-gynx, go to http://www.accessdata.fda.gov/drugsatfda_docs/label/2022/761310s000lbl.pdf.

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