AbbVie has announced that the European Commission (EC) has granted marketing authorization for Elahere (mirvetuximab soravtansine) for the treatment of adult patients with folate receptor-alpha (FRα) positive, platinum-resistant high grade serous epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received one to three prior systemic treatment regimens. This approval marks a significant advancement in the treatment landscape for advanced ovarian cancer, where limited options have been available for patients who develop resistance to platinum-based chemotherapies. Elahere is the first and only folate receptor alpha (FRα)-directed antibody drug conjugate (ADC) medicine approved in the European Union (EU).
Clinical Significance
The approval of Elahere is based on the results of the Phase 3 MIRASOL trial, a global, open-label, randomized, controlled study. The trial compared Elahere to investigator's choice chemotherapy (paclitaxel, pegylated liposomal doxorubicin, or topotecan) in patients with platinum-resistant, high-grade serous ovarian cancer whose tumors express high levels of FRα. Key findings from the MIRASOL trial, presented at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, demonstrated:
- A 35% reduction in the risk of tumor progression or death in patients treated with Elahere compared to chemotherapy (HR 0.65, 95% CI: 0.52, 0.81; p<0.0001).
- A 33% reduction in the risk of death in the Elahere arm compared to chemotherapy (HR 0.67, 95% CI: 0.50, 0.89; p=0.0046).
These results indicate a clinically meaningful improvement in both progression-free survival (PFS) and overall survival (OS) for patients treated with Elahere.
Patient Selection and Companion Diagnostic
Approximately one-third of ovarian cancer patients exhibit high expression of the FRα biomarker. To identify these patients, Roche's VENTANA FOLR1 (FOLR1-2.1) RxDx Assay has also received CE Mark. This immunohistochemistry (IHC) companion diagnostic test allows for accurate determination of FRα status, ensuring that Elahere is prescribed to patients most likely to benefit from the treatment.
Mechanism of Action
Elahere is a first-in-class ADC comprising a folate receptor alpha binding antibody, a cleavable linker, and the maytansinoid payload DM4, a potent tubulin inhibitor. This design allows Elahere to target and kill cancer cells that express FRα, offering a targeted approach to treatment.
Safety Profile
The most common adverse reactions observed with Elahere in clinical trials included blurred vision, nausea, diarrhea, fatigue, and abdominal pain. Healthcare professionals are advised to monitor patients for ocular toxicity, pneumonitis, and peripheral neuropathy, and to adjust or discontinue treatment as necessary based on the severity of adverse reactions.
Impact on Clinical Practice
The approval of Elahere provides a much-needed new treatment option for patients with platinum-resistant ovarian cancer. As Professor Toon Van Gorp from the University of Leuven noted, "It's been 10 years since a new treatment for platinum-resistant ovarian cancer was approved in the EU, and now oncologists have an effective, new, targeted treatment option for these patients."
