A new publication in the American Journal of Respiratory and Critical Care Medicine, headed by senior author prof. Louis Bont of UMC Utrecht makes a plea to consider further development of the SynGEM vaccine. Commenting on the results of the SynGEM RSV clinical trial, the authors indicate that the fail-fast approach that has been adopted by pharmaceutical industry, makes a challenging endeavor for development of RSV vaccines. Applying the fail-fast approach, the SynGEM vaccine was evaluated based on early results, generated until 56 days after start of the clinical trial. These early results were found inconclusive and consequently funding of Mucosis which was sponsor of the clinical trial and owner of the vaccine, was discontinued. The early clinical trial data were however far from complete as long-term immune responses and cellular immunogenicity data were not known when the decision was taken to discontinue funding. The final results of the clinical trial eventually did show such long-term immune responses.
The authors of the commenting paper reveal that in the absence of serological markers of protection to RSV, it is difficult to determine that a vaccine is protective. As indicated by the authors: 'we are left with a trial-and-error approach'.
The authors suggest that testing of the vaccine in a human challenge model may be a quick way to finally determine proof of concept of efficacy.