Mirvetuximab soravtansine improves outcomes over chemotherapy in patients with platinum-resistant ovarian cancer with high folate receptor-alpha (FRα) expression, according to research presented at the ASCO Annual Meeting 2023.
Results from the phase 3 MIRASOL trial showed an improvement in progression-free survival (PFS) and overall survival (OS) with mirvetuximab soravtansine.
“Until this day, no phase 3 study of a novel therapy has ever demonstrated an improvement in overall survival in the platinum-resistant ovarian cancer space,” said study presenter Kathleen N. Moore, MD, of the University of Oklahoma Health Sciences Center in Oklahoma City.
The MIRASOL trial (ClinicalTrials.gov Identifier: NCT04209855) included 453 patients with platinum-resistant ovarian cancer and high FRα expression who had received up to 3 prior lines of therapy.
The patients were randomly assigned to receive mirvetuximab soravtansine (n=227) or investigator’s choice of paclitaxel, pegylated liposomal doxorubicin, or topotecan (n=226). Baseline characteristics were similar between the arms.
Mirvetuximab soravtansine was associated with improvements in PFS, OS, and objective response rate (ORR).
The median PFS was 5.62 months in the mirvetuximab soravtansine arm and 3.98 months in the chemotherapy arm (hazard ratio [HR], 0.65; 95% CI, 0.52-0.81; P <.0001).
The median OS was 16.46 months in the mirvetuximab soravtansine arm and 12.75 months in the chemotherapy arm (HR, 0.67; 95% CI, 0.50-0.89; P =.0046).
The ORR was 42% in the mirvetuximab soravtansine arm and 16% in the chemotherapy arm (odds ratio, 3.81; 95% CI, 2.44-5.94; P <.0001). There were 12 complete responses and 84 partial responses in the mirvetuximab soravtansine arm, compared with 36 partial responses and no complete responses in the chemotherapy arm.
Patients in the mirvetuximab soravtansine arm had a lower rate of grade 3 or higher treatment-emergent adverse events (AEs) than patients in the chemotherapy arm (42% and 54%, respectively). Patients in the mirvetuximab soravtansine arm also had a lower rate of serious AEs (24% vs 33%) and a lower rate of discontinuation due to AEs (9% vs 16%).
Ocular AEs (blurred vision, keratopathy, and dry eye) were more common in the mirvetuximab soravtansine arm than in the chemotherapy arm, but Dr Moore noted that these AEs are typically low grade and reversible, and patients are usually able to continue therapy to maximal benefit.
Hematologic AEs, peripheral neuropathy, and alopecia were more common in the chemotherapy arm. Gastrointestinal AEs were similar between the arms.
“We believe these data are practice-changing and position mirvetuximab as the new standard of care for patients with FRα-positive platinum-resistant ovarian cancer,” Dr Moore said.
Disclosures: This research was supported by ImmunoGen. One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Moore KN, Angelergues A, Konecny GE, et al. Phase III MIRASOL (GOG 3045/ENGOT-ov55) study: Initial report of mirvetuximab soravtansine vs. investigator’s choice of chemotherapy in platinum-resistant, advanced high-grade epithelial ovarian, primary peritoneal, or fallopian tube cancers with high folate receptor-alpha expression ASCO 2023. June 2-6, 2023. Abstract LBA5507.