Soligenix last week announced the results of a Phase 1B clinical trial of an aluminum hydroxide (Alum) adjuvanted formulation of RiVax™, designed to improve the immunogenicity of the vaccine. The results of the study indicate that Alum adjuvanted RiVax™ is safe and well tolerated, and induces greater ricin neutralizing antibody levels in humans than adjuvant-free RiVax™. The results of the study have been published in the online edition of Clinical and Vaccine Immunology (pdf).
The Phase 1B trial was conducted by investigators at the University of Texas Southwestern Medical Center (UTSW) and supported by a combination of grants including a $940,000 grant from the Office of Orphan Products Development (OOPD) of the Food and Drug Administration (FDA).
The trial in healthy volunteers was designed to evaluate the long term safety and immunogenicity of escalating doses of the vaccine up to one year after a primary vaccination, in which the vaccine was administered by intramuscular injections at 0, 6 weeks, and 6 months in doses of 10 and 100 micrograms. The vaccine was well tolerated in all individuals with only mild side effects that are typical of reactions to vaccines injected intramuscularly.
“These positive results indicate a route forward for the further development of the vaccine in larger and more definitive trials in humans and to provide the additional correlates of protective immunity in pivotal animal studies,” said Robert N. Brey, PhD, Chief Scientific Officer of Soligenix. “With the formal Request for Information (RFI) from the Department of Defense regarding the status of ricin toxin vaccine development, we believe that Soligenix is well positioned to collaborate with the DoD on the future development of RiVax™.”
The Centers for Disease Control has classified ricin toxin as a Category B biological agent. Currently, there are no FDA approved therapeutics or vaccines that can be used to protect against ricin exposure or to reverse its effects once exposed.
Through its BioDefense Division, Soligenix is developing countermeasures pursuant to the Biomedical Advanced Research and Development Authority (BARDA) Strategic Plan of 2011-2016 for inclusion in the US government’s Strategic National Stockpile. Soligenix’s lead biodefense products in development are a recombinant subunit vaccine RiVax™, which is designed to protect against the lethal effects of exposure to ricin toxin and VeloThrax™, a vaccine against anthrax exposure.
Both drugs are currently the subject of a $9.4 million National Institute of Allergy and Infectious Diseases (NIAID) grant supporting development of Soligenix’s new vaccine heat stabilization technology known as ThermoVax™. Soligenix is also developing a drug for the treatment of gastrointestinal acute radiation syndrome (GI ARS) under a $600,000 NIAID Small Business Innovation Research (SBIR) grant.