Ricin Vaccine Candidate RiVax® Awarded Patent Protection

A new United States patent has been issued protecting a ricin toxin vaccine candidate, RiVax®. 

This is important news since there are currently no effective treatments for ricin poisoning. 

Biodefense vaccines, such as RiVax, are destined to be deployed in the event of a public health emergency. 

The patent, titled "Multivalent Stable Vaccine Composition and Methods of making same", supports combination vaccines protecting against ricin intoxication, as well as other toxins, such as those associated with anthrax. 

RiVax is Soligenix’s vaccine candidate for the prevention of death following exposure to a lethal dose of ricin toxin using a unique antigen that is completely devoid of the toxic activity of ricin. 

RiVax contains a genetically altered version of a Ricin Toxin A (RTA) chain containing two mutations that inactivate the toxicity of the ricin molecule. 

RiVax has already received orphan drug designation in the US and in Europe. 

Previously, the RiVax antigen has demonstrated safety in two Phase 1 clinical studies, where it has demonstrated significantly enhanced thermostability and 100% protection to non-human primates in preclinical aerosol challenge models.   

This patent further supports the ability to combine the antigen for the RiVax vaccine with other antigens to create a multivalent vaccine for potential protection against multiple biothreats, such as a combination with an anthrax vaccine. 

Ricin toxin is a lethal plant-derived toxin and potential biological weapon because of its stability and high potency, and the fact it is readily extracted from by-products of castor oil production, says the Centers for Disease Control and Prevention (CDC). 

Ricin comes in many forms including powder, mist or pellet.  Ricin can also be dissolved in water and other liquids. 

The CDC estimates that the lethal dose in humans is about the size of a grain of salt.   

Ricin toxin illness causes tissue necrosis and general organ failure leading to death within several days of exposure.  Ricin is especially toxic when inhaled. 

Ricin works by entering cells of the body and preventing the cells from making the proteins it needs.  Without the proteins, cells die, which is eventually harmful to the entire body. 

The development of RiVax has been sponsored through a series of grants from both National Institute of Allergy and Infectious Diseases (NIAID) and the Food and Drug Administration (FDA) and ongoing development is sponsored by NIAID contract # HHSN272201400039C.   

Soligenix, Inc., is a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need.