Using a new trial design, researchers from the South African Tuberculosis Vaccine Initiative (SATVI) will test for infection with Mycobacterium tuberculosis (Mtb) as a marker of the vaccine’s efficacy, producing faster clinical results that could possibly lead to larger randomized trials. The trial also is designed to evaluate the efficacy of the Bacille Calmette-Guerin (BCG) vaccine.
“For the first time in a TB vaccine trial, we will be testing for infection by Mtb, rather than waiting to measure the occurrence of clinical disease, which is more expensive and requires much larger studies,” Thomas G. Evans, MD, president and CEO of Aeras, said in the release. “This will enable us to obtain results much more quickly and with fewer subjects, and the data we generate will ensure that the entire field of TB vaccine R&D progresses in a more informed and streamlined way.”
Nearly 1,000 adolescents from Western Cape province in South Africa will participate in the trial. All participants were vaccinated with BCG as infants; one-third of the cohort will be revaccinated with BCG, one-third will receive the investigational vaccine — H4+IC31 (AERAS-404) — and the remaining participants will receive placebo. Researchers will use a commercially available interferon gamma release assay to determine infection with Mtb.
The new vaccine is being developed by Aeras, Statens Serum Institut and Sanofi-Pasteur. According to Aeras, the vaccine stimulates immune responses by using the H4 antigen — a fusion of Mtb antigens 85B and TB10.4, developed by Statens Serum Institute — and an adjuvant created by biotech company Valneva, named IC31.
Preliminary results from the trial are expected in late 2015.
“Right now, we do not have a reliable way to prevent people who are exposed to Mtb from becoming infected, and one out of 10 people who become infected will develop active TB disease at some point in their life,” said Mark Hatherill, MD, interim director of SATVI. “Preventing new infections by vaccination, and interrupting the cycle of transmission, would make a tremendous impact on the TB epidemic.”