Introduction Current therapies for platinum-resistant ovarian cancer (PROC) are primarily non-platinum chemotherapies with limited response and an important unmet clinical need. Mirvetuximab soravtansine (MIRV) is a folate receptor α (FRα)-directed antibody-drug conjugate which had been approved by FDA in Nov-2022 for FRα positive PROC. IMGN853–301 is a single-arm registration study to evaluate the efficacy and safety of MIRV in Chinese PROC patients.

Methods 35 PROC patients were enrolled with 51% of patients with three lines of prior therapy. All patients received prior bevacizumab; 77% of patients received a prior PARP inhibitor. Eligible patients had FRα-high tumor according to PS2+ methodology from Ventana FOLR1 assay. All patients received single-agent MIRV at 6 mg/kg using adjusted ideal body weight on Day 1 Q3W until progressive disease or intolerable toxicity.

Results As of the data cutoff of 25-April-2023, median follow-up was 4.5 months. In all of 35 evaluable patients by investigator per RECIST 1.1, confirmed and unconfirmed ORR was 31.4% (95% CI: 16.85%, 49.29%), and 3-month PFS rate was estimated as 73.5%(95% CI: 55.30%, 85.25%). The most common (≥20%) treatment-related adverse events (all grade and grade 3–4) were Keratopathy (57.1% and 14.3%) , Aspartate aminotransferase increased (45.7% and 0%), White blood cell count decreased (37.1% and 2.9%), Alanine aminotransferase increased (37.1% and 0%), Vision blurred (37.1% and 17.1%), Platelet count decreased (37.1% and 5.7%), Neutrophil count decreased (37.1% and 5.7%), and Xerophthalmia (20.0% and 14.3%).

Conclusion/Implications MIRV demonstrated consistent clinically meaningful antitumor activity and favorable tolerability and safety in Chinese patients with FRα-high PROC.