ImmunoGen surges ~95% as ovarian cancer drug Elahere shows survival benefit in confirmatory trial

ImmunoGen (NASDAQ:IMGN) said its ovarian cancer drug Elahere showed statistically significant improvements in progression-free survival (PFS) and overall survival (OS) in a confirmatory phase 3 trial.

Based on these data, the company plans to file applications in the EU and the U.S. for conversion to a regular approval of Elahere (mirvetuximab soravtansine-gynx).

The late-stage study, dubbed MIRASOL, evaluated Elahere versus investigator's choice (IC) of single-agent chemotherapy (weekly paclitaxel, pegylated liposomal doxorubicin or topotecan) to treat patients with platinum-resistant ovarian cancer whose tumors express high levels of FRα, and who have received up to three prior regimens.

The main goal of the study was PFS — length of time during/ after treatment that a patient lives without the disease getting worse.

Elahere showed a statistically significant and clinically meaningful improvement in PFS compared to chemo, with a hazard ratio of 0.65, representing a 35% reduction in the risk of tumor progression or death in the Elahere group compared to the chemo arm.

The median PFS in the Elahere group was 5.62 months, compared to 3.98 months for the chemo group.

ImmunoGen said Elahere also showed a statistically significant and clinically meaningful improvement compared to chemo, in OS — a secondary goal.

The median OS was 16.46 months in the Elahere group, compared to 12.75 months for the chemotherapy group. With a hazard ratio of 0.67, representing a 33% reduction in the risk of death in the Elahere arm, compared to the chemo group.

Objective response rate (ORR), another secondary goal, was 42.3% in the Elahere arm including 12 complete responses (CRs), compared to 15.9%, with no CRs in the IC chemo group.

"We believe these data will provide the foundation for pursuing a marketing authorization 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 program to move this therapy into broader populations, including platinum-sensitive disease," said ImmunoGen's President and CEO Mark Enyedy.

The company added that the safety profile of Elahere continued to consist mainly of low-grade eye and gastrointestinal events.

Compared with chemo, Elahere was linked with lower rates of Grade 3 or greater treatment-emergent adverse events (TEAEs) 42% versus 54%.

In November 2022, the FDA granted accelerated approval to Elahere to treat adult patients with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube or primary peritoneal cancer who have received one to three prior systemic therapy regimens.

The approval was based on ORR and duration of response data from a study called SORAYA.

IMGN +95.19% to $10.15 premarket May 3