A Phase I Study of an Agonist CD40 Monoclonal Antibody (CP-870,893) in Combination with Gemcitabine in Patients with Advanced Pancreatic Ductal Adenocarcinoma

Purpose: This phase I study investigated the maximum-tolerated dose (MTD), safety, pharmacodynamics, immunologic correlatives, and antitumor activity of CP-870,893, an agonist CD40 antibody, when administered in combination with gemcitabine in patients with advanced pancreatic ductal adenocarcinoma (PDA). Experimental Design: Twenty-two patients with chemotherapy-naive advanced PDA were treated with 1,000 mg/m(2) gemcitabine once weekly for three weeks with infusion of CP-870,893 at 0.1 or 0.2 mg/kg on day three of each 28-day cycle. Results: CP-870,893 was well-tolerated; one dose-limiting toxicity (grade 4, cerebrovascular accident) occurred at the 0.2 mg/kg dose level, which was estimated as the MTD. The most common adverse event was cytokine release syndrome (grade 1 to 2). CP-870,893 infusion triggered immune activation marked by an increase in inflammatory cytokines, an increase in B-cell expression of costimulatory molecules, and a transient depletion of B cells. Four patients achieved a partial response (PR). 2-[F-18]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) showed more than 25% decrease in FDG uptake within primary pancreatic lesions in six of eight patients; however, responses observed in metastatic lesions were heterogeneous, with some lesions responding with complete loss of FDG uptake, whereas other lesions in the same patient failed to respond. Improved overall survival correlated with a decrease in FDG uptake in hepatic lesions (R = -0.929; P = 0.007). Conclusions: CP-870,893 in combination with gemcitabine was well-tolerated and associated with antitumor activity in patients with PDA. Changes in FDG uptake detected on PET/CT imaging provide insight into therapeutic benefit. Phase II studies are warranted. (C) 2013 AACR.