This phase II clinical trial compared the efficacy and safety of two types of treatment in patients with non-small-cell lung cancer (NSCLC) who had previously been treated with chemotherapy. Patients diagnosed with NSCLC (with either measurable or evaluable lesions) and had been treated with chemotherapy were eligible for this study. They were randomly assigned to two groups. The DOCp53 group received trans-tracheal Adp53 injection (1 x 10(12) vp dosage) on day1 and day8, as well as docetaxel at 75 mgm(-2) on day 2. The DOC group only received docetaxel at 75 mgm(-2) on day 1. Patients in each group received treatment for two cycles before reevaluation. Between February 2005 and December 2006, 40 patients were recruited for this study. In all, 19 of them were assigned to the DOCp53 group and 21 were assigned to the DOC group. After a mean follow-up of 12 months, the median survival time (MST) was 7.7 months (95% CI, 4.53 to 10.84) for patients in the DOCp53 group and 5.9 months (95% CI, 4.11 to 7.68) in the DOC group (P=0.44, log-rank test). In the DOCp53 group, two patients with diffuse metastatic disease of lung had partial response (PR) in addition to eight with stable disease (SD). No PR and 13 SD were observed in the DOC group. Toxic reactions that could be attributed to the Adp53 vector were transient fever and limited hemoptysis. For patients with relapsed NSCLC, trans-tracheal injection of Adp53 in addition to docetaxel did not improve overall survival or efficacy. However, direct trans-tracheal injection of Adp53 proved to be a safe procedure, with tolerable levels of toxicity. Cancer Gene Therapy (2011) 18, 444-449; doi:10.1038/cgt.2011.15; published online 1 April 2011