Screening for a new clinical study, called RV305, recently began at the Bang Lamung Hospital in
the Chonburi Province of Thailand. This small immunogenicity study will evaluate extended boosting regimens using
the same vaccine components that were used in RV144. The goal of the secondary boost is to try to extend and increase the immune response seen in RV144.
This is the first of two planned clinical trials that will evaluate extended boosting regimens using the same vaccine components that were used in RV144. The next study, RV306, should begin later in 2012.
RV144 results suggest that the protection against HIV appeared highest at 6-12 months, based on post-hoc analysis (60%, 95% CI 22, 80).
Researchers seek to sustain or increase this effect, and these clinical trials will enable them to collect more data and samples for immunogenicity studies.
RV305 will test three late-boost regimens in RV144 trial participants who received the full vaccination schedule at either of two sites in Chon Buri Province, Thailand. At weeks zero and 24
either placebo or active vaccine will be administered to participants. Group one will receive both vaccine products used in the RV144 trial—ALVAC and AIDSVAX. Group two
will receive only AIDSVAX and group three will receive only ALVAC. The outcome of this trial will help determine the most appropriate vaccination schedule for a future planned efficacy trial.