...While Onyx Adenovirus Shows Promise In Phase I

Another company targeting the p53 gene in cancer therapy is Onyx, whichreported the first results of a Phase I study of its adenoviral treatment for cancer, ONYX-015. This is a genetically-engineered adenovirus which has been shown to replicate in and kill tumor cells deficient in p53 protein, without harming cells with normal copies of the p53 gene.

Results of the Phase I study were presented at ASCO by Daniel Von Hoff of the University of Texas Health Science Center at San Antonio, USA. The primary objectives of the study were to determine the safety of injecting ONYX-015 directly into tumors of the head and neck, to determine the maximum tolerated dose, and to assess the safety of repeat treatment. Dr Von Hoff reported that there were no dose-limiting toxicities among the 27 patients participating in the trial, including 10 patients who received repeat injections with the drug. The only consistent side effect was flu-like symptoms.

The secondary objective of the study was to give a preliminary assessment of efficacy, and of 19 patients whose follow-up is complete, three experienced a partial response of more than 50% reduction in the size of their injected tumors, while one experienced a reduction of over 70%. An additional three patients exhibited significant necrosis in their injected tumors, according to Dr Von Hoff, while several patients experienced lesser degrees of tumor necrosis, including five whose tumors were stable and non-progressive following treatment.