Use of the immunomodulator ubenimex (bestatin) increases survival among patients receiving surgical treatment for squamous cell lung cancer according to results of a Phase III trial. Ubenimex (Bestatin) is a mold-derived molecule with multiple effects on the immune system, including stimulation of cytokine release.

Per study design, 400 patients who had undergone complete resection of Stage I squamous cell lung cancer were randomized to receive either ubenimex (bestatin) or placebo. The trial was limited to patients who had received no therapy prior to surgery, and trial participants were treated for 2 years.

Overall 5-year survival was significantly increased for patients receiving ubenimex (bestatin) (81%) compared with those receiving placebo (74%). Disease-free survival was also significantly higher in the Ubenimex group compared with the placebo group (71% vs. 62%).

Little toxicity occurred in either treatment group. There were no significant differences in occurrence of toxicity between the two groups except for anorexia, which occurred in 15% of those receiving ubenimex (bestatin) compared with 7% of those receiving placebo.

In addition to immunomodulating effects, ubenimex (bestatin) has been shown to inhibit angiogenesis, induce apoptosis, and interact with aminopeptidases involved in antigen presentation. It also inhibits invasion of human metastatic cells in an in vitro model. It is not yet clear which of ubenimex's (bestatin's) multiple properties contribute to its anticancer effects in vivo.

Based on the encouraging results of the Phase III study in squamous cell lung cancer, future studies are planned for ubenimex (bestatin) in treatment of other squamous cell cancers.