The primary objective of Trial B is to evaluate the safety and biologic feasibility of the MTD of PDGF-B/Ad5 reported in Trial A in a standard 24-week trial for treatment of a venous leg ulcer. For this study, 15 consecutive patients will be treated using the MTD. All patients will receive a single intra-ulcer injection of PDGF-B/Ad5 and a limb compression bandage to be changed weekly.Study participants will be followed for 24 weeks, which is the length of most FDA-approved venous leg ulcer trials.