ImmunoGen has reported positive data from the SORAYA clinical trial of mirvetuximab soravtansine (mirvetuximab) monotherapy in folate receptor alpha (FRα)-high platinum-resistant ovarian cancer patients.

The trial was carried out in patients who had earlier received treatment with Avastin (bevacizumab). 

An antibody-drug conjugate, mirvetuximab soravtansine contains a folate receptor alpha-binding antibody, cleavable linker and the maytansinoid payload DM4 for destroying the targeted cancer cells.

The single-arm trial analysed the safety and efficacy of mirvetuximab in FRα-high platinum-resistant ovarian cancer patients, who previously received one to three regimens with a minimum of one including bevacizumab. 

A total of 106 subjects with a median of three previous lines of treatment were enrolled in the trial.

Investigator-evaluated confirmed objective response rate (ORR) was the trial’s primary endpoint while the duration of response (DOR) was the key secondary endpoint.

Furthermore, ORR was evaluated by blinded independent central review (BICR). 

Findings showed that the trial met the primary endpoint with confirmed investigator evaluated ORR being 32.4% including five complete responses (CRs).

ORR by BICR was 31.6% with five CRs observed. 

The median DOR was reported to be 6.9 months by investigator while the median PFS was 4.3 months and 5.5 months, by investigator and BICR, respectively.

Mirvetuximab was well-tolerated and the safety profile was in line with the known data observed in over 700 subjects treated in the larger mirvetuximab programme. 

Low-grade and usually reversible treatment-associated adverse events were noted in the trial with blurred vision, keratopathy and nausea being the most common ones.

The company intends to file Biologics License Application (BLA) for mirvetuximab this month in the US.

ImmunoGen senior vice-president and chief medical officer Anna Berkenblit said: “Based on the impressive anti-tumour activity, durability of response, and safety profile observed in SORAYA, we believe mirvetuximab has the potential to displace single-agent chemotherapy as the standard of care for FRα-high platinum-resistant ovarian cancer.”