Tumor p53 biomarkers personalize selection of adenoviral p53 gene therapy or methotrexate as potentially efficacious treatments in different and complementary groups of recurrent squamous cell carcinoma of the head and neck (SCCHN)

B36 Biomarkers of the p53 target of adenoviral p53 gene therapy (Advexin) were evaluated for their ability to predict efficacy in 186 patients with recurrent SCCHN. Biomarker profiles predictive of adenoviral p53 efficacy were based upon p53 gene configurations assessed by sequence analyses and their level of protein expression determined by immunohistochemistry. The absence of high level protein expression of “dominant negative” p53 mutations that can block p53 activity were predictive of adenoviral p53 efficacy. In a Phase 3 randomized controlled trial comparing adenoviral p53 and methotrexate, p53 biomarker profiles in the adenoviral p53 treated patients favorable for adenoviral p53 efficacy were associated with a statistically significant increased survival compared to patients with unfavorable p53 profiles (median survival 7.2 vs. 2.7 months, p