Vical begins Ph I trial of prime-boost HIV vaccination strategy

San Diego, USA-based Vical says it has initiated a National Institutes of Health-sponsored Phase I clinical trial of a "prime-boost" vaccine strategy for patients already infected with HIV. The assessment involves eliciting an immune response using multiple doses of the firm's plasmid DNA vaccine, before amplifying this response with a single dose of an adenoviral vector-based vaccine, given at a later date.

The product was originally developed by researchers at the National Institute of Allergy and Infectious Diseases, and is also being assessed in a preventative setting in individuals not infected with HIV.

The vaccine used in the prime-boost trial incorporates modified versions of the gag, pol and nef genes from the subtype B virus, most common in Europe and the USA, as well as a recombinant version of the env gene based on that found in the A and C subtypes, which are predominant in Africa and Asia. The program which is designed to evaluate the treatment's safety, will be carried out at the NIH's Clinical Center in Bethesda, Maryland.