Tuberculosis vaccine trial results offer potential for new BCG strategies
Aeras announced results from an innovative clinical trial that provides encouraging new evidence that Tuberculosis vaccines could prevent sustained infections in high-risk adolescents. In a prevention-of-infection Phase 2 trial conducted in South Africa, revaccination with the Bacille Calmette-Guerin vaccine significantly reduced sustained TB infections in adolescents. An experimental vaccine candidate, H4:IC31, also reduced sustained infections, although not at statistically significant levels. However, the trend observed for H4:IC31 is the first time a subunit vaccine has shown any indication of ability to protect against TB infection or disease in humans. TB infections that developed during the study were determined using a QuantiFERON-TB Gold in Tube test, a commercially available blood test that helps diagnose TB infections. In the trial, individuals who tested negative for QFT-GIT were considered to not have a TB infection. The trial measured the rate by which individuals converted to QFT-GIT positive, implying evidence of TB infection. Those individuals who tested QFT-GIT positive consecutively over 6 months were considered to have a sustained infection. The study evaluated H4:IC31 vaccination and BCG revaccination for safety, immunogenicity and the ability to prevent initial and sustained TB infections among healthy adolescents in the Western Cape Province of South Africa. H4:IC31 is an investigative subunit vaccine candidate being developed jointly by Aeras and Sanofi Pasteur, the vaccines business of Sanofi, and the Statens Serum Institut. BCG is the only licensed tuberculosis vaccine available globally.