PlantForm | Newsroom | New patent for AntoXa Corporation's plant-made anti-ricin antibody manufacturing process

New patent for AntoXa Corporation's plant-made anti-ricin antibody manufacturing process

PhD9 antibody drug being developed under licence with Defence Research & Development Canada (DRDC)

GUELPH, Ont., Canada, January 30, 2024 —The Canadian Intellectual Property Office has allowed a patent application for a plant-based manufacturing process to produce an antibody for treatment of ricin exposure, developed by AntoXa Corporation under license from Defence Research & Development Canada (DRDC).

Canadian Patent Application No. 3,045,161, “Production of Ricin Antibodies in Plant,” is the latest outcome of research and development by AntoXa and DRDC, an agency of Canada’s Department of National Defence, to develop the PhD9 monoclonal antibody (mAb) treatment in plants.

The process was granted a U.S. patent in early 2023. AntoXa, which has an exclusive license from DRDC to develop and produce PhD9 for global markets, last fall also announced a strategic collaboration agreement with Belgium-based SwiftPharma to attract investment and accelerate advancement of the drug in European, Middle Eastern and African (EMEA) markets.

“This latest patent success provides further validation that our plant-based vivoXPRESS® platform uniquely addresses the need for cost-effective production of antibody drugs for a variety of applications, including antidotes for ricin and other potential bioterrorism threats,” said Dr. Don Stewart, CEO of AntoXa. “We are currently raising the necessary capital required to complete R&D and clinical activities in anticipation of commercializing the mAb treatment for ricin exposure in the next two to three years.”

Patents related to the PhD9 antibody manufacturing process are issued to the Queen and King in Right of Canada as represented by the Minister of National Defence. The 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.

Ricin, a naturally occurring protein from the castor-bean plant, Ricinus communis, is extremely toxic to humans when inhaled or injected. There is currently no approved antidote against ricin poisoning. 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. It acts very quickly and leaves a short window for administering therapeutic antibodies.

The PhD9 antibody drug candidate prevents ricin from penetrating cells. Previous in vitro and in vivo studies conducted by DRDC found the plant-made version of the antibody showed therapeutic efficacy against ricin intoxication.

In addition to securing financing, next steps for commercialization of PhD9 include transitioning to large-scale GMP manufacturing, product characterization, animal safety and efficacy studies, and a Phase 1 clinical trial. Medical countermeasures do not require Phase 2 or Phase 3 human efficacy trials, and the path to regulatory approval is shorter than for other pharmaceuticals.


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

About AntoXa Corporation (

AntoXa Corporation is a Canadian biopharmaceutical company developing medical countermeasures to protect military and civilian personnel from biological and chemical agents, as well as outbreaks of naturally occurring infectious diseases.

A wholly-owned subsidiary of PlantForm Corporation, AntoXa holds an exclusive license to the vivoXPRESS® biopharmaceutical manufacturing platform to produce countermeasures for ricin, sarin and soman, as well as other defence-related therapeutics.

vivoXPRESS® technology uses Nicotinia benthamiana  plants to produce biopharmaceuticals in less than six weeks at a significantly lower cost of goods compared to industry standard fermentation systems.


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