Soligenix Inc is a late-stage biotechnology company developing products to treat the life-threatening side effects of cancer treatments and gastrointestinal diseases, as well as vaccines for certain bioterrorism agents. RiVax™ is the company’s proprietary vaccine developed to protect against exposure to ricin toxin, a plant toxin with the potential to be a bioterror threat. RiVax is the most advanced vaccine in the company’s portfolio.

The company today issued a press release pointing to the February 2010 edition of Vaccine, in which an article describing prelinical formulations of RiVax was published.

RiVax is currently being evaluated in phase 1 human safety and immunogenicity trials, as well as non-human primate trials, with the end-point of establishing long-term storage options of RiVax.

Ellen Vitetta, director of the Cancer Immunobiology Center at UT Southwestern and an author of the study, said that the results showed the vaccine to be stable in lyophilization, or freeze drying, which results in longer vaccine stability.

“We know that the ricin subunit vaccine itself is very sensitive to denaturation, and we are very encouraged to find lyophilization conditions that aid in the long-term stability of the vaccine,” Dr. Vitetta stated in the press release. “We are also pleased to see that in our study storage for over one year at ambient conditions resulted in no apparent degradation of potency or the integrity of the protein immunogen.”

Robert N. Brey, Ph.D., chief scientific officer of Soligenix, said the trials suggest broader storage options for various vaccines and opens the door for additional research and development.

“These results are very promising not only for the future development of RiVax in particular, but also for the potential development of other vaccines with long-term stability, especially those using conventional adjuvants composed of aluminum salts,” Dr. Brey stated. “Our current efforts are centered on combining conventional adjuvant and scalable lyophilization techniques to examine formulations that retain stability at elevated temperatures, building on the results that Dr. Vitetta and her colleagues have reported in this publication.”

Per the press release, the full article (Smallshaw and Vitetta, “A lyophilized formulation of RiVax, a recombinant ricin subunit vaccine, retains immunogenicity,” Vaccine) is available online at