ELAHERE Demonstrates Overall Survival Benefit in the Phase 3 MIRASOL Trial in Patients with FRα-Positive Platinum-Resistant Ovarian Cancer - Seite 2

Key Findings from MIRASOL

MIRASOL enrolled 453 patients; 14% had one prior line of therapy, 39% had two prior lines of therapy, and 47% had three prior lines of therapy. 62% of patients received prior bevacizumab; 55% received a prior PARP inhibitor. As of the data cutoff on March 6, 2023, the median follow-up time for OS was 13.1 months; 14% of patients on the ELAHERE arm remained on study drug compared to 3% on the IC chemotherapy arm.

• ELAHERE demonstrated a statistically significant and clinically meaningful improvement in OS compared to IC chemotherapy. With 204 OS events reported as of March 6, 2023, the median OS was 16.46 months in the ELAHERE arm, compared to 12.75 months in the IC chemotherapy arm, with a hazard ratio (HR) of 0.67, p=0.0046. This represents a 33% reduction in the risk of death in the ELAHERE arm in comparison to the IC chemotherapy arm.
• ELAHERE demonstrated a statistically significant and clinically meaningful improvement in PFS by investigator assessment compared to IC chemotherapy, with a hazard ratio of 0.65 (p<0.0001), which represents a 35% reduction in the risk of tumor progression or death in the ELAHERE arm compared to the IC chemotherapy arm. The median PFS in the ELAHERE arm was 5.62 months, compared to 3.98 months in the IC chemotherapy arm.
• ORR by investigator assessment in the ELAHERE arm was 42.3%, including 12 complete responses (CRs), compared to 15.9%, with no CRs, in the IC chemotherapy arm.
• PFS and ORR results by blinded independent central review were concordant with investigator assessment.
• The safety profile of ELAHERE continues to consist predominantly of low-grade ocular and gastrointestinal events. No new safety signals were identified. Compared with IC chemotherapy, ELAHERE was associated with lower rates of:
  • Grade 3 or greater treatment-emergent adverse events (TEAEs) (42% vs 54%);
  • Serious adverse events (24% vs 33%); and
  • TEAEs leading to discontinuation of study drug (9% vs 16%).

"We are elated with the positive top-line results from MIRASOL. We believe the impressive efficacy data and consistent safety data reinforce ELAHERE's benefit for patients with platinum-resistant ovarian cancer," said Anna Berkenblit, MD, Senior Vice President and Chief Medical Officer of ImmunoGen. "Importantly, ELAHERE is the first drug to show an overall survival benefit in this patient population. These results are remarkable and we extend our appreciation to all of the patients and physicians who participated in MIRASOL. We look forward to presenting full data from the trial at a medical meeting later this year."