 This study is an open-label, non-randomized phase I study, followed by open-label non-randomized phase II study. The first cohort of patients will receive 200 milligrams mg of MK-3475 by intravenous infusion over a 21-day period called a cycle along with Gemcitabine 1250 mgm2 given on Days 1 and 8 of each 21-day cycle for up to 6 cycles. Patients will be seen in the study clinic 12 times over 126 days for an evaluation of signs and symptoms that may represent drug toxicity. Patients may continue to receive MK-3475 without gemcitabine for up to 2 years. 