Randomized multicenter, phase II study of CO-101 versus gemcitabine in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) and a prospective evaluation of the of the association between tumor hENT1 expression and clinical outcome with gemcitabine treatment.

4007 Background: Gemcitabine requires membrane transporter proteins to cross the cell membrane. Low expression of the human equilibrative nucleoside transporter-1 (hENT1) may play a role in gemcitabine resistance in PDAC. CO-101 (also known as CP-4126), a lipid-drug conjugate of gemcitabine, was rationally designed to enter cells independently of hENT1 and to circumvent transporter-mediated resistance. We conducted a randomized, controlled trial (LEAP) in patients with mPDAC to determine whether CO-101 improved survival vs gemcitabine in patients with low hENT1 tumors. The study also prospectively tested the hypothesis that gemcitabine is more active in patients with hENT1 high than hENT1 low tumors in metastatic disease. Methods: Patients were randomized to CO-101 or gemcitabine. An immunohistochemistry test measuring tumor hENT1 expression was developed in parallel with the recruitment phase of LEAP. To dichotomize the population, a hENT1 cut-off was defined using primary PDAC tumor samples from an adju...