Promising HIV
vaccine trial data prompt Merck to double enrollment

Pharmaceutical company Merck announced this week that it plans to double the enrollment in its clinical trial of an experimental HIV vaccine after initial data showed the vaccine significantly increased immune system activity against the virus, The Wall Street Journal reports. The trial is evaluating whether the vaccine, called MRKAd5, can help stimulate immune system responses to help control HIV in those already infected or prevent infection in HIV-negative people. The vaccine uses a common cold virus to deliver several key HIV genes into the body. Once the immune system recognizes and mounts an attack against the genes, it also remains primed to attack whole copies of the virus in the body. Early study data show the vaccine boosted the number of immune system cells with specific anti-HIV activity by 50 to 100 times their pre-vaccine levels. A total of 3,000 volunteers will now be enrolled in the trial, which began in January. Final results are not expected before the end of 2008. (Advocate.com)