Plant molecular farming, also known as biopharming, takes the healing potential of plants to a whole new level.
Plants have been used to make medicine for centuries; however, prior to the emergence of plant biotechnology, drugs were extracted or derived from the plant itself. The pain- and fever-relieving properties of willow tree bark were known long before chemists isolated its active ingredient and created acetylsalicylic acid (ASA) or Aspirin; the historical use of poppy-derived medicines led to the development of opiates such as codeine and morphine that continue to play an essential role in modern health care.
Today, plants and plant cell systems can be genetically engineered to serve as drug-producing factories for a wide array of antibodies and other protein-based therapeutics and vaccines, known collectively as plant-made pharmaceuticals (PMPs).
The emergence of plant-made pharmaceuticals
Early work on plant-made pharmaceuticals focused on using food crops, such as corn and rice, with the goal of creating a cheap, efficient way to deliver vaccines. Progress in this area slowed around 2002 due to concerns about cross contamination of other field crops, prompting interest to shift to tobacco and other non-food crops grown in controlled environments or isolated fields.
In the early 1990s, Canadian plant scientist Dr. J. Christopher Hall recognized the manufacturing and regulatory advantages of using transgenic tobacco plants to produce antibody drugs. Hall held the Canada Research Chair in Recombinant Antibody Technology from 2002-2014 at the University of Guelph where his lab developed a tobacco-plant-based biopharmaceutical platform, now called vivoXPRESS® and licensed to PlantForm Corporation, the company he co-founded in 2008.
The plant advantage
Plant-based systems offer a number of important advantages over other fermentation systems for producing biologic drugs, including:
quick, unlimited scale-up
rapid, high-yield production
enhanced safety (lower risk of contamination from animal and/or human pathogens)
the ability to produce novel and complex molecules that animal cell cultures cannot
Today, there are a number of companies developing plant-made pharmaceuticals, some using tobacco, others using duckweed, moss, alfalfa and other plants.
The first PMP approved for human use was Elelyso (taliglucerase alfa), an enzyme produced in carrot cells by Israel-based Protalix Biotherapeutics Inc. (commercial rights sold to Pfizer in 2015). The FDA approved Elelyso for Gaucher’s disease in 2012.
In 2015, the FDA granted LeafBio Inc. (Mapp Biopharmaceutical, Inc.) Fast Track designation for a plant-made drug called ZMapp for treatment of Ebola virus disease.
Biologics now dominate the global pharmaceutical market, with sales anticipated to reach USD$390 billion by 2020 (IMS Institute for Healthcare Informatics, 2016). Six of the top 10 global drug products in 2015 were biologics – a trend that is expected to continue in 2016.
1982 Insulin is the first recombinant protein produced using E.coli bacteria
1990 First plant-derived pharmaceutical protein was human serum albumin produced using transgenic tobacco and potato plants
2006 World's first licensing of injectable, plant-made vaccine: Dow AgroSciences vaccine for Newcastle disease in poultry, made using tobacco plants, is approved in the United States.
2008 PlantForm Corporation is established with a groundbreaking manufacturing platform to produce therapeutic biologics and biosimilar versions of approved antibody drugs.
2012 Elelyso, by Protalix BioTherapeutics/Pfizer, is the first plant cell-based enzyme replacement therapy approved by the FDA. Manufactured in carrot cells, the drug is used to treat Gaucher disease.
2014 ZMapp, an experimental drug made from antibodies produced in tobacco plants, is used successfully to treat human patients with Ebola virus.