Phase I trial of sequential administration of recombinant DNA and adenovirus expressing L523S protein in early stage non-small-cell lung cancer

L523S is an immunogenic lung cancer antigen that has demonstrated preclinical safety when the gene is injected intramuscularly as an expressive plasmid (pVAX/L5235) and when delivered following incorporation into an El B-deleted adenovirus (Ad/L523S). We performed a phase I clinical trial in 13 stage IB, IIA, and IIB non-small-cell lung cancer patients. pVAX/L523S (8 mg on days 0 and 14 in all cohorts) and Ad/L523S (1, 20, 400 x 10(9) vp on days 28 and 56, cohorts 1, 2, and 3, respectively) were administered to 3 patients in each of three cohorts. No significant toxic effect was identified. All but 1 patient demonstrated greater than or equal to twofold elevation in anti-adenovirus antibodies. One of 10 evaluable patients demonstrated L523S-specific antibody by direct IgG ELISA. Two patients developed disease recurrence and all remain alive after a median of 290 days follow-up. Results suggest a high level of safety but evidence of L523S-directed immune activation was limited, suggesting a need for modification of dose, schedule, and site of vaccination (i.e., intradermal) with further clinical testing.