Clinical Summary:

• Design/Population: The phase 2 IMGN853-0420 trial evaluated mirvetuximab soravtansine plus carboplatin in patients with FRα-expressing recurrent platinum-sensitive ovarian cancer, including patients previously treated with PARP inhibitors.
• Key Outcomes: Mirvetuximab soravtansine plus carboplatin demonstrated meaningful clinical activity in both PARP inhibitor-naïve and PARP inhibitor-exposed patients. Outcomes were more favorable in patients whose disease progressed after completing PARP inhibitor therapy and in those with longer prior PARP inhibitor exposure.
• Clinical Relevance: These findings suggest that mirvetuximab soravtansine plus carboplatin remains an active treatment option in this population and support further investigation in this setting. 

Results from the phase 2 IMGN853-0420 trial demonstrated that mirvetuximab soravtansine plus carboplatin remained active in patients with folate receptor alpha (FRα)-expressing recurrent platinum-sensitive ovarian cancer, regardless of prior PARP inhibitor (PARPi) exposure, although outcomes varied according to PARPi treatment.

These findings were presented by Ainhoa Madariaga, MD, 12 de Octubre University Hospital, Madrid, Spain, at the European Society for Medical Oncology (ESMO) Gynecological Cancers Congress in Copenhagen, Denmark. 

In this single-arm trial, 125 patients received 6 to 8 cycles of mirvetuximab soravtansine (6 mg/kg adjusted ideal body weight) plus carboplatin (AUC 5) every 3 weeks, followed by mirvetuximab soravtansine monotherapy. Primary end points included objective response rate (ORR) and progression-free survival (PFS), according to prior PARPi exposure, duration of prior PARPi treatment, and timing of disease progression. 

Among enrolled patients, 49% had previously received PARPi therapy. Of those patients, 37 experienced disease progression while receiving PARPi and 24 experienced progression after completing PARPi. The median platinum-free interval was 13.4 months overall, including 10.7 months among patients with progression during PARPi treatment and 22.0 months among those with progression after PARPi.

At analysis, the ORR was 68% in the overall study population. Response rates were 72.6% in PARPi-naïve patients and 63.9% in patients previously exposed to PARPi. Among PARPi-exposed patients, the ORR was 59.5% in those whose disease progressed during PARPi treatment and 70.8% in those whose disease progressed after completing PARPi.

Median PFS was 11 months in the overall population, 12.4 months in PARPi-naïve patients, and 10.4 months in PARPi-exposed patients. Patients with progression during PARPi treatment had a median PFS of 7.7 months compared with 12.7 months among those whose disease progressed after completing PARPi.

Investigators also observed a trend toward improved outcomes with longer prior PARPi exposure. ORRs were 40%, 63.6%, and 72.4% in patients treated with PARPi therapy for less than 6 months, 6 to 12 months, and more than 12 months, respectively. Median PFS was 5.4 months, 10.6 months, and 11.3 months across the respective groups. 

“In FRα-expressing recurrent platinum-sensitive ovarian cancer, mirvetuximab plus carboplatin was efficacious, including in patients with prior PARP inhibitor exposure,” concluded Dr Madariaga and coauthors.

Source:

Oaknin A, Lim P, Santin AD, et al. Mirvetuximab soravtansine (MIRV) plus carboplatin (Carbo) in folate receptor alpha (FRα)- positive platinum-sensitive ovarian cancer (PSOC): Outcomes by prior poly (ADP-ribose) polymerase inhibitor (PARPi). Presented at ESMO Gynecological Cancers Congress. June 17-19, 2026. Copenhagen, Denmark. Abstract 107O.