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Health Canada has approved mirvetuximab soravtansine (Elahere) for the treatment of adult patients with folate receptor alpha (FRα)–positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received one to three prior systemic treatment regimens.¹
The decision makes mirvetuximab soravtansine the first FRα-targeted antibody-drug conjugate (ADC) available in Canada for this patient population. The approval was supported by findings from the phase 3 MIRASOL trial (NCT04209855), in which mirvetuximab soravtansine demonstrated significant efficacy improvements over investigator’s choice of chemotherapy.
Treatment with mirvetuximab soravtansine led to statistically significant improvements in overall survival (OS; HR, 0.67; 95% CI, 0.50-0.88; P = .0046) and progression-free survival (PFS; HR, 0.65; 95% CI, 0.52-0.81; P < .0001). The overall response rate (ORR) was 42% (95% CI, 35.8%-49.0%) with mirvetuximab soravtansine vs 16% (95% CI, 11.4%-21.4%) with chemotherapy, including a complete response rate of 5% vs 0%, respectively.
“Ovarian cancer poses many unique challenges for women. In addition to vague symptoms and late-stage diagnosis, many patients develop a resistance to current treatments that increases their risk of poor survival outcomes,” Tania Vrionis, chief executive officer of Ovarian Cancer Canada, stated in a news release. “The approval of [mirvetuximab soravtansine] in Canada is not only welcome news for women in our community, but also a critically needed update to their care. This decision gives them another treatment option and can help improve outcomes for those who are no longer responding to surgery and chemotherapy.”
In March 2024, the FDA granted regular approval to mirvetuximab soravtansine-gynx for adult patients with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have previously received 1 to 3 systemic treatment regimens.2 This decision was also supported by data from MIRASOL.
MIRASOL Trial Breakdown
The randomized phase 3 trial evaluated the efficacy and safety of mirvetuximab soravtansine in patients with platinum-resistant ovarian cancer with high levels of FRα expression who had received 1 to 3 prior systemic treatment regimens.3 Patients needed to have platinum-resistant disease, and radiographic progression following their most recent line of therapy was required. Other key inclusion criteria included measurable disease per RECIST 1.1 criteria, an ECOG performance status of 0 or 1, and adequate hematologic, liver, and kidney function.
In the experimental arm, patients received single-agent mirvetuximab soravtansine at a dose of 6 mg/kg adjusted ideal body weight (AIBW), administered intravenously on day 1 of every 3-week cycle. In the comparator arm, patients were treated with a chemotherapy agent chosen by the investigator, including paclitaxel administered at 80 mg/m² on days 1, 8, 15, and 22 of a 4-week cycle; topotecan administered either at 4 mg/m² on days 1, 8, and 15 of a 4-week cycle or at 1.25 mg/m² on days 1 through 5 of a 3-week cycle; or pegylated liposomal doxorubicin (PLD) administered at 40 mg/m² on day 1 of a 4-week cycle. If tolerated, PLD could subsequently be administered as a 1-hour infusion beginning with Cycle 2.
The primary end point of the study was PFS by investigator assessment, with key secondary end points including ORR and OS.
Safety Analysis
In terms of safety, serious adverse effects (AEs) were observed in 24% of patients who received mirvetuximab soravtansine.1 The most common serious AEs reported in at least 2% of patients included pleural effusion (3%), abdominal pain (3%), intestinal obstruction (2%), ascites (2%), and small intestinal obstruction (2%).
“Platinum-resistant ovarian cancer is a challenging disease with limited effective therapies and a poor prognosis,” Shannon Salvador, MD, president of the Society of Gynecologic Oncologists of Canada, an associate professor at McGill University, and director of the Gynecologic Oncology Subspecialty Residency Program, added in a news release. “This approval marks a critical advancement in the treatment of advanced ovarian cancer. [Mirvetuximab soravtansine] has been shown to extend the survival of patients and offers a much-needed new option for those facing this form of gynecological cancer, which has the lowest survival rate in Canada.”
References
- Health Canada approves Elahere® for certain types of platinum-resistant ovarian cancers. News Release. Abbvie. Accessed September 3, 2025. https://www.abbvie.ca/content/dam/abbvie-dotcom/ca/en/documents/press-releases/ELAHERE-press-release-EN.pdf
- FDA approves mirvetuximab soravtansine-gynx for FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. FDA. Accessed March 22, 2024. Accessed September 3, 2025. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-mirvetuximab-soravtansine-gynx-fra-positive-platinum-resistant-epithelial-ovarian
- A study of mirvetuximab soravtansine vs. investigator’s choice (ic) of chemotherapy in platinum-resistant, advanced high-grade epithelial ovarian, primary peritoneal, or fallopian tube cancers with high folate receptor-alpha (frα) expression (MIRASOL). Clinicaltrials.gov Updated August 27, 2025. Accessed September 3, 2025. https://www.clinicaltrials.gov/study/NCT04209855