PlantForm | Newsroom | U.S. Patent Granted for Made-in-Canada Ricin Antibody Technology

U.S. Patent Granted for Made-in-Canada Ricin Antibody Technology

GUELPH, Ont., CANADA, Feb. 27, 2023 — The U.S. Patent Office has granted a patent for a plant-based manufacturing process to produce an antibody for treatment of ricin exposure, an outcome of research and development by AntoXa Corporation under contract with Defence Research & Development Canada (DRDC), an Agency of the Canadian Department of National Defence.

AntoXa, a wholly-owned subsidiary of Canadian biopharmaceutical company PlantForm Corporation, has an exclusive license from DRDC to develop and produce the PhD9 monoclonal antibody treatment in plants for sale in markets worldwide. The process has received United States Patent No. 11,447,789, issued to His Majesty the King in Right of Canada as represented by the Minister of National Defence.

“Our plant-based, made-in-Canada manufacturing platform uniquely addresses the critical need for cost-effective, large-scale production of antidotes for ricin and other potential bioterrorism threats,” said Dr. Don Stewart, PlantForm President and CEO. “Safety and efficacy studies showed therapeutic efficacy against ricin intoxication and validate the capability of our proprietary vivoXPRESS® manufacturing platform to produce a best-in-class antibody treatment for ricin exposure.”

Ricin, a naturally occurring protein from the castor-bean plant, Ricinus communis, is extremely toxic to humans when inhaled or injected. It is listed as a Category B threat agent by the U.S. Centers for Disease Control and Prevention due to its ease of production, worldwide availability, relative stability and extreme lethality. There is currently no approved antidote against ricin poisoning. It acts very quickly and leaves a short window for administering therapeutic antibodies.

The PhD9 antibody drug candidate prevents ricin from penetrating cells. The PhD9 anti-ricin antibody was developed, in part, through a collaborative effort by the Medical Countermeasure Consortium (MCMC) under the Chemical, Biological and Radiological Memorandum of Understanding (CBR MOU), which includes Australia, Canada, the United Kingdom and the United States of America.

Next steps for the commercialization of PhD9 are to manufacture a GMP lot for further pre-clinical studies and a Phase 1 human clinical trial, which is dependent on raising the necessary funds for scale up and other activities necessary to obtain regulatory approvals, Stewart said. Medical countermeasures do not require Phase 2 and Phase 3 human efficacy trials for ethical reasons, therefore the path to regulatory approval is shorter than for other pharmaceuticals.

About AntoXa Corporation (
AntoXa Corporation, a wholly-owned subsidiary of PlantForm Corporation, is developing medical countermeasures to protect military and civilian personnel from biological and chemical agents, as well as outbreaks of naturally occurring infectious diseases. The company’s pipeline includes countermeasures for ricin, sarin, soman and Ebola Sudan, as well as other defence-related therapeutics.

About PlantForm Corporation (
PlantForm Corporation is a biopharmaceutical company focused on the ultra-low-cost production of specialty antibody and protein drugs and vaccines using the proprietary vivoXPRESS® plant-based manufacturing platform. The vivoXPRESS plant expression system reduces biologic drug production costs by as much as 90% compared to standard mammalian cell systems. The platform is fast (drug production in as little as six weeks), versatile and easily scalable. PlantForm’s pipeline features an innovative antidote to ricin exposure, and biosimilar versions of the brand name biologic drugs Keytruda® and Lucentis®. Learn more.


For more information, please contact:

Don Stewart
President and CEO, PlantForm Corp.
+1 416-452-7242

Stacey Curry Gunn
Director of Communications, PlantForm Corp.
+1 519-827-1131

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