Soligenix (SNGX.Q), a biopharma company that develops and commercializes products for rare diseases, announced that its RiVax, which is a heat stable ricin toxin vaccine, has received a fast track designation from the US Food and Drug Administration (FDA).
First, a few points.
Fast track designation is given by the FDA when there’s a desperate need for a drug intended to treat a serious or life threatening condition. Potential vaccines for the Wuhan coronavirus will get the fast track designation, ditto for any other fast-acting exceptionally dangerous disease or condition. It helps push in-demand drugs to the front of the development and distribution line. For instance, should events transpire to require it, Soligenix will be eligible to submit a biologics license applications (BLA) for RiVax on a sufficiently expedited basis, permitting the FDA to review sections of the BLA before receiving the complete submission.
“We are very pleased to have been granted fast track designation from the FDA to go along with the orphan drug designation previously received. We believe that the FDA’s action in granting fast track designation validates the unmet medical need that currently exists for a vaccine providing protection against lethal ricin toxin exposure and for the potential key role RiVax® can serve as a part of the US Strategic National Stockpile,” stated Christopher J. Schaber, PhD, president and chief executive officer of Soligenix.
Now what’s Ricin and why is it fast tracked?
Ricin is a lethal plant-derived toxin and potential biological weapon. It’s extracted from by-products of castor oil production. It comes in either powder, mist or pellet, and can be dissolved in water and other liquids. The CDC estimates that a lethal dose is roughly the size of a grain of salt. Ricin stops the proteins within cells from replicating, effectively causing cell death, leading to tissue necrosis and general organ failure, and kills within a few days of exposure.
The Public Health Agency of Canada breaks down the symptoms of ricin poisoning that differ depending on the method of exposure.
- Ingested: Symptoms include nausea, vomiting, abdominal cramps and diarrhea and appear within 2 to 4 hours, leading to severe dehydration, liver and kidney failure and death.
- Inhaled: symptoms include nausea, fever, cough, chest tightness and difficulty breathing. This could lead to fluid in the lungs, respiratory failure and death.
- Injected: The muscles and lymph nodes near the injection site would die. This could lead to organ failure and death.
At present there aren’t any effective treatments for ricin poisoning (which is an excellent reason to find one). The development of an effective vaccine would act as a deterrent against ricin being used as a biological weapon, and could be used to vaccinate military personnel and civilian emergency responders at risk of potential exposure if some group did use it as a biological weapon.
The spectre of ricin has resurfaced recently in the form of an envelope addressed to President Trump that was thought to contain the lethal toxin.
Ricin and RiVax
Wikipedia counts 28 separate incidents involving ricin dating back to clandestine Cold War stuff straight out of a John LeCarre novel in 1978, and the latest being a ricin terrorist plot in Cologne, Germany in 2018, so suffice it to say, there’s decent enough call for this product.
RiVax has been funded through a series of grants from the National Institute of Allergy and Infectious Diseases (NIAID). The potential vaccine contains a genetically altered version of a ricin toxin A (RTA) chain containing two mutations that inactivate the toxicity of the ricin molecule. The Phase 1A clinical trial conducted with a formulation of RiVax did not contain an adjuvant. The trial revealed dose dependent seroconversion as well as lack of toxicity of the molecule when administered into the muscle of human volunteers.
The adjuvant-free formulation of RiVax induced toxin neutralizing antibodies that lasted up to 127 days after the third vaccination in several individuals.
Given how nasty ricin is and the threat it poses when any idiot with an internet connection can find and download how to convert castor oil into a deadly poison, any progress is welcome.