ImmunoGen has reported positive top-line results from the Phase III confirmatory MIRASOL trial (GOG 3045/ENGOT OV-55) of ELAHERE (mirvetuximab soravtansine-gynx) for the treatment of folate receptor alpha (FRα)-positive platinum-resistant ovarian cancer.

The randomised study is designed to evaluate the safety and efficacy of ELAHERE against the investigator’s choice of single-agent chemotherapy.

It enrolled 453 patients with platinum-resistant ovarian cancer whose tumours express high FRα levels. They were also previously treated with up to three lines of therapy.

Progression-free survival (PFS) by investigator assessment is the primary endpoint while objective response rate (ORR) and overall survival (OS) are key secondary endpoints of the study.

The study showed statistically significant improvements in PFS, ORR, and OS compared to chemotherapy.

No new safety signals were identified and ELAHERE’s safety profile continues to consist of low-grade ocular and gastrointestinal events predominantly.

ImmunoGen president and CEO Mark Enyedy said: “We believe these data will provide the foundation for pursuing a marketing authorisation (MAA) in Europe and elsewhere, and seeking full approval in the US, support our goal of delivering ELAHERE to FRα-positive patients worldwide, and reinforce our conviction in our clinical development programme to move this therapy into broader populations, including platinum-sensitive disease.

“ELAHERE’s differentiated safety and efficacy data provides further validation of our leading antibody-drug conjugates (ADCs) platform and broad clinical pipeline of novel ADCs for solid tumours and haematologic malignancies.”

The company plans to submit MAA in Europe and a supplemental Biologics License Application in the US in the next half of this year.