: TZT-1027, a derivative of dolastatin-10, has a wide spectrum of in vitro activity against cancer cell lines. We conducted a phase 2 trial of TZT-1027 in patients with previously treated non-small cell lung cancer (NSCLC). Patients with stage IV or recurrent NSCLC who had received one prior platinum-based chemotherapy regimen were eligible. Patients received 2.4mg/m(2) of TZT-1027 on days 1 and 8 of a 21-day cycle. The primary endpoint was response rate as measured by RECIST. Thirty-two patients were enrolled (16 women, 16 men). The most common grade 3/4 adverse effects were leukopenia and neutropenia. Four patients died within 30 days of receiving TZT-1027, three from progressive disease and one with pneumonia and neutropenia. No objective response was observed (0% observed rate, 95% confidence interval 0-11%). The median time to progression was 1.5 months. The median overall survival was 8.5 months. This phase 2 trial showed that TZT-1027 administered on days 1 and 8 of a 21-day cycle had no anticancer activity. Further development of TZT-1027 in patients with previously treated NSCLC is not warranted.