Patients receive modified vaccinia virus ankara vaccine expressing p53 subcutaneously (SC) on day 15 and gemcitabine hydrochloride intravenously (IV) over 30 minutes on days 1 and 8. Treatment repeats every 21 days for up to 3 courses in the absence of disease progression or unacceptable toxicity. Patients then continue to receive gemcitabine hydrochloride IV over 30 minutes on days 1 and 8 every 21 days in the absence of disease progression or unacceptable toxicity.