Soligenix, Inc., a late-stage biopharmaceutical company, announced today that the US Food and Drug Administration (FDA) has granted Orphan Drug Designation to RiVax for the prevention of ricin intoxication. RiVax is a proprietary vaccine that contains a recombinant subunit of the A chain of ricin toxin which induces ricin neutralizing antibodies in humans and animals.

The US Orphan Drug Act is intended to assist and encourage companies to develop safe and effective therapies for the treatment of rare diseases and disorders that affect fewer than 200,000 individuals within the United States. In addition to providing a seven-year term of market exclusivity for RiVax upon FDA approval, Orphan Drug Designation also positions Soligenix to be able to take advantage of certain financial and regulatory benefits, including government grants for conducting clinical trials, waiver of FDA user fees for the potential submission of a Biologics License Application for RiVax, and certain tax credits.

RiVax induces a protective immune response in animal models of ricin exposure and is currently being evaluated in humans. A human phase I A clinical trial of RiVax has been completed and a phase I B clinical trial remains ongoing. Results of the phase I A clinical trial of RiVax indicated that the immunogen was safe and induced antibodies anticipated to protect humans from ricin exposure. The outcome of the study was published in the Proceedings of the National Academy of Sciences (Vitetta et al., 2006, PNAS, 105:2268-2273).

The phase I B trial, sponsored by University of Texas South-western Medical Centre in Dallas (UT South-western), is currently evaluating a more potent formulation of RiVax. Soligenix has developed processes for large-scale manufacturing of the vaccine product and is developing the product using animal models for efficacy under the FDA animal rule. RiVax was invented by Ellen Vitetta, PhD, Director of the Cancer Immunobiology Centre and colleagues at UT South-western.

“The FDA's decision to grant RiVax Orphan Drug Designation for the prevention of ricin intoxication marks another important step forward in our biodefense pipeline,” stated Christopher J. Schaber, PhD, president and CEO of Soligenix. “Marketing exclusivity through Orphan Drug Designation adds significantly to the existing patent estate surrounding RiVax. We are enthusiastic about the prospects of developing a ricin vaccine to anticipate civilian and military bio-defence requirements and for potential government stockpiling."

RiVax is Soligenix's proprietary vaccine developed to protect against exposure to ricin toxin and is the most advanced vaccine in the company's portfolio. RiVax has been shown to induce a protective immune response in animal models of ricin exposure and in human clinical trials. The current phase I B clinical trial is being supported by a grant to UT South-western from the FDA's Office of Orphan Products.

The development of RiVax to date has been sponsored through a series of overlapping challenge grants (UC1) and cooperative grants (U01) from the National Institutes of Allergy and Infectious Diseases (NIAID) which were granted to Soligenix and to UT South-western where the vaccine originated. Soligenix and UT South-western have collectively received approximately $25 million in grant funding from the NIH for development of RiVax and related vaccine technologies.

Ricin toxin is a toxin thought to be a potential bio-terror threat because of its stability and high potency as well as the large worldwide reservoir created as a by-product of castor oil production. Ricin toxin is relatively easy to produce and exposure to small amounts, especially by inhalation, can lead to lung damage, nausea, fever, abdominal pain, and death within several days.

Exposure to ricin results in local tissue necrosis, and general organ failure leading to death within several days of exposure. The potential use of ricin toxin as a biological weapon has been highlighted in an FBI terrorism report, which states that “Ricin and the bacterial agent anthrax are emerging as the most prevalent agents involved in WMD investigations.”

There are currently no effective means to prevent the effects of ricin intoxication. The successful development of an effective vaccine against ricin toxin may act as a deterrent against the actual use of ricin as a biological weapon and could be used in rapid deployment scenarios in the event of a biological attack. RiVax would potentially be added to the Strategic National Stockpile and dispensed in the event of a terrorist attack.

Soligenix, Inc. is a late-stage biopharmaceutical company developing products to treat life-threatening side effects of cancer treatments and serious gastrointestinal diseases, and vaccines for certain bioterrorism agents. Through its bio-defence division, Soligenix is developing biomedical countermeasures pursuant to the project Bio-Shield Act of 2004.

Soligenix's lead bio-defence product in development is a recombinant subunit vaccine called RiVax, which is designed to protect against the lethal effects of exposure to ricin toxin. RiVax has been shown to be well tolerated and immunogenic in a phase I clinical trial in normal volunteers.

Soligenix's lead product, orBec (oral beclomethasone dipropionate), is a potent, locally acting corticosteroid being developed for the treatment of acute gastrointestinal Graft-versus-Host disease (GI GVHD), a common and potentially life-threatening complication of hematopoietic cell transplantation. orBec is currently the subject of a $1.2 million FDA Orphan Products Grant-supported confirmatory phase III clinical trial for the treatment of acute GI GVHD.

Soligenix is also conducting a National Cancer Institute (NCI)-supported phase I/II clinical trial of SGX201 in the prevention of acute radiation enteritis. Additionally, Soligenix has a Lipid Polymer Micelle (LPM) drug delivery technology for the oral delivery of leuprolide for the treatment of prostate cancer and endometriosis.