OBJECTIVES: I. Established the safety of VX-710 in combination with doxorubicin and vincristine for the treatment of patients with recurrent small cell lung cancer. II. Characterized the plasma pharmacokinetics of this regimen in patients. III. Established the ability of this regimen to improve the response rate to chemotherapy in patients who relapsed on front-line therapy. IV. Evaluated the multidrug resistance profile of these patients following this treatment regimen.