Background: Bestatin is a potent aminopeptidase inhibitor that has immunostimulant and antitumor activity. We conducted a prospective randomized, double-blind, placebo-controlled trial to determine whether postoperative adjuvant treatment with bestatin could prolong the survival of patients with completely resected stage I squamous-cell lung carcinoma.
Methods: Patients with confirmed, resected stage I squamous-cell lung carcinoma were randomly assigned to receive either bestatin (30 mg) or placebo daily by mouth for 2 years. We assessed whether bestatin treatment was associated with overall survival and 5-year cancer-free survival and assessed its safety. All statistical tests were two-sided.
Results: From July 8, 1992, through March 30, 1995, 402 patients were entered in the study, 202 in the bestatin group and 198 in the placebo group. The median follow-up for surviving patients was 76 months (range = 58-92 months). The 5-year overall survival was 81% in the bestatin group and 74% in the placebo group for a difference of 7% (95% confidence interval [CI] = -1.4% to 15.0%). The 5-year cancer-free survival was 71% in the bestatin group and 62% in the placebo group for a difference of 9% (95% CI = -0.7% to 17.8%). Overall survival (P =.033, log-rank test) and cancer-free survival (P =.017, log-rank test) were statistically significantly different by Kaplan-Meier analysis. Few adverse events were observed in either group.
Conclusions: Survival was statistically significantly better for patients with completely resected stage I squamous-cell lung carcinoma who were treated with bestatin as a postoperative adjuvant therapy than for those who received a placebo. This result requires confirmation in other phase III trials.