A Phase III, Double-blind, Multicenter, Randomized Study in Chemonaive Patients with Locally Advanced or Metastatic Pancreatic Cancer to Compare a Combination Therapy of Virulizin® plus Gemcitabine versus Placebo plus Gemcitabine; Optional Secondline Therapy may Include Continuation of Virulizin® or Placebo, Alone or in Combination with 5-Fluorouracil.