EV-301: Phase III study to evaluate enfortumab vedotin (EV) versus chemotherapy in patients with previously treated locally advanced or metastatic urothelial cancer (la/mUC).

Abstract

TPS497 Background: Standard first-line treatment for patients (pts) with la/mUC is cisplatin-based chemotherapy or carboplatin-based chemotherapy for pts unfit for cisplatin. Immune checkpoint inhibitors (CPIs) are standard treatment options for pts who progressed during or after platinum-based chemotherapy. While some pts with la/mUC achieve durable responses with CPIs, less than 25% of pts respond. Following failure of a CPI, no therapies are approved. Enfortumab vedotin is a fully humanized monoclonal antibody that delivers the microtubule-disrupting agent monomethyl auristatin E to tumors expressing Nectin-4, which is expressed in 97% of mUC pt samples (Petrylak et al. ASCO, 2017). In a phase 1 study (EV-101; NCT02091999), single-agent EV 1.25 mg/kg was generally well tolerated and demonstrated a confirmed objective response rate (ORR) of 42% across the overall population of pts with mUC; in pts with prior CPI therapy or liver metastasis at baseline confirmed ORRs of 42% and 36% were observed. A pivotal phase 2 study of EV in la/mUC pts with prior CPI treatment (EV-201; NCT03219333) is ongoing. Methods: EV-301 is a global, multicenter, open-label phase 3 trial (NCT03474107) enrolling adult pts with la/mUC and an ECOG performance status score ≤1, who have received a prior platinum-containing chemotherapy, and have experienced disease progression during or following treatment with a CPI. Approximately 550 pts will be randomized (1:1) to receive EV (1.25 mg/kg) administered by IV infusion over approximately 30 minutes on Days 1, 8, and 15 of each 28-day cycle ( Arm A), or investigator choice of IV docetaxel, paclitaxel, or vinflunine (EU only) on Day 1 of each 21-day cycle ( Arm B). Treatment with the study drug will continue until radiological disease progression, intolerance, or other discontinuation criterion is met. Radiological assessments of tumor response status will be performed at baseline and every 8 weeks. The primary endpoint is overall survival; secondary endpoints include progression-free survival, duration of response, and overall response rate, as well as assessment of safety/tolerability, and quality-of-life parameters. Clinical trial information: NCT02091999.