A randomized phase II trial of mirvetuximab soravtansine in folate receptor alpha (FRα)–high recurrent ovarian cancer eligible for platinum-based chemotherapy (MIROVA/AGO-OVAR 2.34).

5506 Background: Mirvetuximab soravtansine (MIRV) has demonstrated single agent activity in patients with platinum-resistant ovarian cancer with FRα high expression. However, its activity and safety in combination with carboplatin has not been defined in platinum eligible patients so far. Methods: Randomized phase II trial comparing 6 cycles of carboplatin AUC5+MIRV 6 mg/kg AIBW every 3 weeks followed by MIRV versus 6 cycles of carboplatin combined with either paclitaxel, gemcitabine or pegylated liposomal doxorubicin followed by maintenance PARP inhibitor (PARPi) if applicable. All histologic subtypes were eligible with a platinum-free interval >3 months and FRα high expression (≥75% with PS2+ scoring) confirmed by central laboratory. Prior PARPi therapy in BRCAmut patients was mandatory. Strata were BRCA-Status, TFIp and number of prior lines of chemotherapy. The primary endpoint was PFS. Results: In total, 145 patients were randomized. Of them, 112/145 (77.2%) patients had received prior bevacizumab and 97/145 (66.9%) had prior PARPi, 15.2% were BRCAmut. In the standard arm, 39.15% received PARPi as maintenance. Median PFS in the standard arm was 9.79 months versus 9.53 months in the experimental arm (p=0.996; HR=1.00; 95% CI: 0.68; 1.46). Conclusions: MIROVA/AGO-OVAR 2.34 is the first randomized trial evaluating the activity and safety of the combination of carboplatin with an antibody-drug conjugate in the setting of platinum-eligible relapsed ovarian cancer. The primary endpoint regarding improvement of PFS was not met. Further analysis will be presented. Clinical trial information: NCT04274426 .