Q. What is Pharma-Planta?
Pharma-Planta is a research consortium representing 33 academic and industry partners in Europe and South Africa. It is funded by the European Union under the Framework 6 programme for Research and Development. Its focus is the development of strategies for the production of pharmaceutical proteins in plants.
Q. What is 'molecular farming in plants'?
This can be defined as the use of agricultural plants for the production of useful molecules for non food, feed or fibre applications. In most cases, this means medically-relevant molecules such as recombinant human proteins, antibodies and vaccines, but it can also include enzymes, novel polymers and technical reagents. Plants are already grown to produce valuable molecules, including many drugs. Molecular farming is different because the plants are genetically modified to enable them to produce the molecules we want them to.
Q. What are 'recombinant human proteins'?
A lot of the proteins our bodies make have medical uses (think of insulin, which is used to treat diabetes, and growth hormone, which is used to treat growth disorders). In the past, such proteins were recovered from human cadavers or isolated from animals, but this was risky because the proteins were often contaminated with viruses and other disease-causing agents. Recombinant human proteins are produced in genetically modified cells. The human gene is transferred into these cells, and they produce the corresponding protein efficiently and safely.
Q. Why use plants?
Many pharmaceutical proteins and industrial enzymes have been produced by genetically engineered microbes and cultured mammalian cells, but these systems have two major problems. First, proteins that are made in microbes are often not exactly the same as the human counterparts, because the cells lack the ability to synthesize all the correct components. Second, mammalian cells are very expensive to grow and they still may harbour viruses. Because of this there is a severe lack of production capacity throughout the world, and expensive processing and purification methods are required to ensure the final product is free of disease-causing agents. Plants are able to produce authentic recombinant proteins, agricultural production is inexpensive and unlimited in scale, and many plants are considered to be safe based on the fact that we eat them every day without ill effects.
Q. Given these advantages, will all therapeutic proteins eventually be produced by molecular farming?
No. While many therapeutic proteins can be produced in plants, others cannot. In some cases, the proteins cannot be synthesized properly in plant tissues, while in other cases the costs are too high. Generally, the costs of production by molecular farming in plants are lower than other production systems, but the cost of recovering functional products may be too high in some cases to make production economically feasible.
Q. Are there specific advantages to producing vaccines in plants?
Yes. Vaccines produced in plants are very stable, particularly those expressed in seeds and fruits, which means that it will be far easier to store and distribute them in parts of the developing world where refrigerators and freezers are difficult to come by. Also, plants offer the perfect medium for administering oral vaccines both to adults and children. Plants can also be grown very quickly, allowing the development of rapid-response vaccines to pandemic threats.
Q. Is plant molecular farming going on already in Europe?
Although there is no commercial molecular farming in Europe at the current time, there have been some field trials to study the advantages and disadvantages of different production systems.
Q. Are plants used for molecular farming safe for the environment?
There is a lot of debate, particularly in Europe, about the potential risks of genetically modified plants in the environment. An additional issue in the case of molecular farming is that the plants will contain products that may have potent pharmacological effects in humans and animals that consume them. For this reason, Pharma-Planta only grows its pharmaceutical plants in containment greenhouses.
Q. Are medicines produced in plants safe for humans?
One of the key objectives of the Pharma-Planta project was to develop a plant-based production system that meets all the regulatory demands that govern the production of pharmaceutical products. The system currently used to manufacture medicines is called good manufacturing practice (GMP), which is a very strict set of guidelines ensuring that all components and materuals used in the production process meet a defined quality standard. We have developed a plant-based system which complies with GMP. The purpose of the Pharma-Planta clinical trial is to demonstrate the safety of a plant-derived pharmaceutical protein in human volunteers.