Tanzania Tuberculosis Vaccine Trial

The DarDar Tuberculosis Vaccine Trial was sponsored by the National Institutes of Health and conducted from 2001-2008 among 2,013 HIV-infected volunteers in Dar es Salaam, Tanzania. Subjects were adults with CD4 counts >200 and childhood BCG immunization and were randomized 1:1 to receive 5 intradermal doses of inactivated SRL-172 (an environmental non-tuberculous mycobacterium) or identical placebo. In the process of screening asymptomatic subjects for active tuberculosis the study team identified the new clinical entity of subclinical tuberculosis.

The trial was stopped by the Data and Safety Monitoring Board when the vaccine was judged to have shown efficacy based on a trend in protection against the primary endpoint of disseminated tuberculosis and a statistically significant reduction in the secondary endpoint of definite culture-confirmed tuberculosis. The main effects manuscript was published in AIDS in 2010 and the immunogenicity manuscript in Vaccine in 2010.

The trial supports the concept of a polyantigenic vaccine as an effective approach to the prevention of tuberculosis in HIV-infected adults. A broth manufacturing process for SRL-172 has been developed by Aeras for the vaccine now known as DAR-901. DAR-901 has been added to the Aeras TB vaccine portfolio and is in a Phase I trial in the United States.