A preventive vaccine against hepatitis C virus (HCV) that would potentially be the first in that class is entering a Phase I/II clinical trial, according to the Basel, Switzerland-based biopharmaceutical company Okairos. 
   This is the first multicenter, double-blinded, randomized, placebo-controlled trial of a vaccine to prevent HCV infection, the company stated. The trial, born of collaboration between Okairos and the National Institute of Allergy and Infectious Diseases, will be conducted by co-principal investigators from Johns Hopkins University and the University of California, San Francisco.
   The Phase I/II trial follows promising Phase I results published in January in Science Translational Medicine (Barnes et al. 2012;4:115ra1). In that study in healthy volunteers, the T-cell–based preventive vaccine was safe and well tolerated, and, the authors reported, it was shown possible “to generate very strong, broad, long-lasting, and functional T-cell responses against HCV in healthy donors using an adenovirus-based approach.” The Phase I/II trial will test the vaccine’s potential effectiveness in protecting against chronic HCV infection.
   Enrolling 350 subjects, the trial will begin with an interim Phase I analysis of safety and immunogenicity data in a subset of the participants. The study’s primary endpoints will measure the incidence of chronic HCV infection, and the vaccine’s safety and tolerability.
   Okairos’ HCV vaccine is based on a technology platform that uses proprietary, chimpanzee-derived adenovirus vectors to stimulate a robust T-cell response against selected antigens. Okairos plans to develop other T-cell vaccines against infectious diseases for which there are currently no effective vaccines, and to pursue therapeutic vaccines to treat cancer.
—Based on an Okairos press release and the article in Science Translational Medicine