Soligenix announces promising preliminary results from study on ricin toxin vaccine

Sep 2 2014

Soligenix, Inc. (OTCQB: SNGX) (Soligenix or the Company), a clinical stage biopharmaceutical company focused on developing products to treat serious inflammatory diseases where there remains an unmet medical need, as well as developing several biodefense vaccines and therapeutics, announced today promising preliminary results from a preclinical study with its ricin toxin vaccine RiVax™, in a non-human primate (NHP) lethal aerosol exposure model. The study demonstrated that NHPs vaccinated with RiVax™ were completely protected against a lethal aerosol of ricin toxin with a highly significant survival benefit (p<0.002). RiVax™, manufactured with the Company's thermostabilization platform technology ThermoVax™, was used to vaccinate NHPs to assess efficacy against lung exposure to ricin toxin in an animal model that is anticipated to respond to vaccination similarly to humans. ThermoVax™ provides for stabilized, lyophilized (freeze-dried) subunit vaccines that are resistant to exposure to heat, avoiding refrigeration during storage and distribution.

In this pilot study, the ability of the stabilized RiVax™ vaccine to protect against an aerosolized form of ricin toxin was evaluated. Animals were exposed to an aerosol of ricin toxin 3-5 times the amount that is known to result in death of untreated animals. In the case of vaccinated NHPs, the vaccine regimen was safe and well-tolerated, with all of the animals developing antibodies in their sera that neutralized the activity of ricin toxin. More importantly, all of the NHPs in the RiVax™-vaccinated treatment group survived when exposed to the respiratory aerosol of ricin toxin, with no apparent signs of gross lung damage. Conversely, all NHPs in the unvaccinated treatment group died within approximately 36 hours of exposure to aerosolized ricin while developing severe lung damage, including hemorrhaging.

"We are extremely pleased with the positive preliminary efficacy results with RiVax™ in NHPs. This particular study is a critical step along the path of establishing efficacy under the FDA 'animal rule' which dictates that efficacy in animals must be ascertained in cases where a drug or vaccine cannot be ethically tested for efficacy in humans," stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. "It is clear that vaccination with heat stable RiVax™ resulted in robust protection against lung exposure, the most dangerous and likely way that ricin toxin could be used. We anticipate further development of RiVax™ in order to conduct human safety and immunogenicity trials along with advanced manufacturing."

The vaccination and exposure studies were conducted at the Tulane National Primate Research Center (TNPRC) under the direction of Dr. Chad Roy, Director of Infectious Disease Aerobiology. These studies were performed under sponsorship of a National Institute of Allergy and Infectious Disease (NIAID) cooperative grant to Soligenix with TNRPC and other collaborators.

Source: Soligenix, Inc.