Patients receive gemcitabine IV over 30 minutes on day 1 of weeks 1-7 and oral erlotinib once daily beginning on day 3 of week 1 and continuing for 8 weeks (course 1). Patients receive subsequent courses of therapy comprising gemcitabine once weekly for 3 weeks and erlotinib once daily. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity.