Randomized Phase Ii Trial Of The Carboxylesterase (Ces)-Converted Novel Drug Edo-S7.1 In Patients (Pts) With Advanced Biliary Tract Cancers (Btc)

264Background: The novel drug EDO-S7.1 (CAP7.1) is converted to active etoposide by CES allowing administration of higher doses, reducing resistance, and permitting treatment of advanced tumors. Methods: The primary objective was to compare disease control rate (DCR) in 22 pts with unresectable BTC randomized 1:1 to 3-week cycles of EDO-S7.1 (200 or 150mg/m2; iv) given on days (d) 1–5, or best supportive care (BSC) until progression (assessed every 4 weeks). Secondary objectives were progression-free survival (PFS), time to treatment failure (TTF), overall survival (OS) and safety. BSC pts could crossover to EDO-S7.1 upon progression. Results: DCR favored EDO-S7.1 (55.6% [CI 21.2, 86.3] vs BSC (20.0% [2.5, 55.6]; treatment difference –12.80, 72.39). More EDO-S7.1 treated pts achieved sustainable stable disease (SD) or partial response (PR) vs BSC. Progressive disease occurred in 40% EDO-S7.1 vs 70% BSC pts. Three pts (30%) who progressed on BSC achieved SD following crossover to EDO-S7.1, and one pt (10%)...