Background: Ovarian cancer (OC) is the most lethal gynecologic cancer, accounting for ≈185,000 deaths worldwide in 2018. Most patients (pts) initially respond to platinum-based chemotherapy (chemo), but more than 50% of pts recur. Pts who recur in ≤6 months have platinum-resistant OC (PROC), which is associated with poor prognosis. Standard therapy for PROC includes chemo ± bevacizumab (bev). However, many pts receive single-agent chemo, which demonstrates limited response and survival (≈12% ORR, 3-4 mo PFS, ≈12 mo OS). Therefore, there is an urgent need for novel therapeutic strategies. Tissue factor (TF) is a novel oncogenic target expressed in OC. Tisotumab vedotin (TV) is a first-in-class antibody drug conjugate comprising a TF-targeted fully human monoclonal antibody conjugated to the microtubule-disrupting agent monomethyl auristatin E. TV has shown encouraging antitumor activity and a manageable safety profile in PROC in the multicohort phase 1/2 innovaTV 201 study. innovaTV 208 is a multicenter, open-label, phase 2 trial with a safety run-in phase for a dose-dense regimen (DDR) evaluating the efficacy and safety of TV in pts with PROC. Methods: innovaTV 208 will enroll ≈142 adult pts with platinum-resistant epithelial ovarian, primary peritoneal, or fallopian tube cancer; measurable disease by RECIST v1.1; and ECOG score 0-1. Eligible pts must have received bev-containing treatment for OC. Pts with platinum-refractory disease, increased risk of bleeding, active ocular surface disease, or grade > 1 peripheral neuropathy will be excluded. A safety run-in phase for the DDR will be performed in up to 12 pts who received ≤5 prior treatment regimens for PROC. In the DDR, TV will be given at previously decided lower doses IV 3Q4W for the same dose intensity as the standard 1Q3W dose; the primary endpoint is incidence of DLTs. In phase 2, pts who received ≤1 prior cytotoxic chemo regimen for PROC will be randomized to receive TV administered as IV 1Q3W or as IV 3Q4W, if shown to be tolerable. The primary endpoint for phase 2 is confirmed ORR by RECIST v1.1. Secondary endpoints include DOR, time to response, DCR, CA-125 response rate by GCIG criteria, PFS, OS, pharmacokinetics, and safety. Clinical trial information: NCT03657043