RiVax human trials return positive results

The aluminum hydroxide adjuvanted RiVax has induced immune responses in human volunteers, according to Phase 1B clinical trials from Soligenix.

The company announced that the adjuvanted RiVax was found to be safe and well tolerated in the study, which induced better ricin neutralizing antibody levels in humans compared to the adjuvant-free RiVax, PBR reports.

Robert Brey, the chief scientific officer at Soligenix, said that the positive results show a route forward for the further development of the vaccine with the help of larger human trials.

"The Phase 1B results demonstrate that well characterized adjuvants can improve the performance of highly purified subunit antigens such as the one contained in RiVax," Brey said, PBR reports. "The next steps for the development of RiVax will include the evaluation of secondary adjuvants to enhance the induction of neutralizing antibodies in fewer doses and the employment of our ThermoVax technology to stabilize the ingredients of the vaccine for long term storage at ambient temperature conditions."

The study found the vaccine to be well tolerated with mild side effects characteristic of reactions to intramuscularly injected vaccines. All of the subjects developed neutralizing antibodies against ricin toxin at peak antibody titers determined two weeks after the third vaccination, PBR reports.

All of the subjects receiving high or low doses of the vaccine in the Phase 1B trial were 100 percent seropositive at nine months after the first vaccination, with 60 percent remaining positive at one year.