Background: Mirvetuximab soravtansine (MIRV) is an ADC comprising a FRα-binding antibody, cleavable linker, and the maytansinoid DM4, a potent tubulin-targeting agent. As part of the Phase 1b FORWARD II trial (NCT02606305), the combination of MIRV with bevacizumab (BEV) was evaluated in pts with FRα-positive (medium/high expression; ≥ 50%/ ≥75% of cells with PS2+ staining intensity), platinum agnostic ovarian cancer, defined as pts with either platinum resistant (PR) (recurrence within 6 months after last platinum dose) or platinum sensitive (PS) responded to the last platinum therapy received before study entry and did not progress within 6 months) disease for whom a non-platinum based doublet would be appropriate. Methods: Pts received MIRV (6 mg/kg; adjusted ideal body weight) and BEV (15 mg/kg) on Day 1 of a 21-day cycle. Responses were assessed by investigator according to RECIST 1.1 and adverse events (AEs) evaluated by CTCAE v4.03. Results: In total, 60 pts received the combination, with a median age of 60 years, and a median of 2 prior lines of systemic therapy (range 1-4). Platinum status was determined for 56 pts, with 30 (50%) considered PR and 26 (43%) considered PS; platinum status data were incomplete for 4 pts. The most common treatment related AEs (percent all grade/grade 3+) were diarrhea (65/2), blurred vision (62/3), nausea (55/0), and fatigue (55/5). The most common treatment related grade 3+ AEs were hypertension and neutropenia, (10% each); all other grade 3+ events occurred in ≤ 5% of pts. Serious AEs regardless of relationship to study drug were infrequent, with the most common events being small intestinal obstruction in 3 pts, 5% (grade 3) and pneumonitis in 3 pts, 5% (2 grade 1; 1 grade 2). Objective responses were seen in 26 pts for a confirmed overall response rate (ORR) of 43% (95% CI, 31, 57). In a subset analysis of pts with high FRα expressing tumors (n = 33), the confirmed ORR was 61% (95% CI, 42, 77), with an ORR of at least 50% in each of the PR and PS subsets. With a median follow-up of 5.5 months, the duration of response and progression free survival data are immature. Conclusions: The combination of MIRV with BEV demonstrates an encouraging ORR with a favorable tolerability profile in pts with recurrent ovarian cancer regardless of platinum sensitivity, particularly in those with tumors that express high levels of FRα. Clinical trial information: NCT02606305