Randomized, open-label, phase II trial of gemcitabine with or without bavituximab in patients with nonresectable stage IV pancreatic adenocarcinoma.

4054 Background: Despite advances in the treatment of metastatic pancreatic cancer (PC), there is critical need to develop novel therapies.Median survival with combination chemotherapy is limited to less than one year and only the optimally conditioned patients can tolerate these therapies. Bavituximab (B) is a monoclonal antibody (mAB) directed againstphosphatidylserine (PS) that causes vascular shutdown and reactivation of the innate and adaptive immunity in animal models. Preclinical data in mouse PC models indicate that gemcitabine (G) increases PS exposure and the addition of a mAb targeting PS reduces tumor burden, visible liver metastases, microvessel density, and increases tumor macrophage infiltration compared to G alone (Beck et al. 2006). The purpose of this trial is to evaluate and compare the efficacy and safety of the combination of G+B vs. G alone as first line therapy in pts. with nonresectable Stage IV PC. Methods: Seventy patients were randomized (1:1) to receive G 1000 mg/m2 on days 1, 8, and 15 every 28Edays with or without weekly B 3mg/kg IV until disease progression or unacceptable toxicities. Key eligibility criteria were Stage IV PC, ECOG ≤2, measurable disease, age≥18 years, total bilirubin ≤1.5xULN, and adequate renal, hematologic, and hepatic function. The primary efficacy endpoint was overall survival (OS) and secondary endpoints included overall response rate (ORR) and progression free survival (PFS). Results: Of the 70 (G/G+B 34/36) patients randomized, 67 (G/G+B 33/34) received study treatment and 63 (G/G+B 31/32) were evaluable. No significant difference was seen in age, gender, race or ECOG. At analysis 87% deaths had been reported in G and 72% in G+B group. Median OS estimate is 5.2 months for G and 5.6 months for G+B. No difference between groups was observed in PFS (median 3.9 months for G and 3.7 months for G+B). ORR was 13% for G and 28% for G+B. Most AEs were grade 1-2 and typical of exposure to G. Conclusions: In this patient population with extensive disease burdens and limited treatment options, G+B was well tolerated and demonstrated moderate activity in tumor response and survival. Clinical trial information: NCT01272791.