The research was presented by Charles Arntzen at the national meeting of the American Chemical Society (ACS). Arntzen explained that using tobacco plants quantities for clinical trials can be ready in eight to 10 weeks, with commercial scale being achieved within four months.
Genetically modified tobacco mosaic virus was used to infect the plants, turning cells into norovirus vaccine factories. This method has been used by other researchers and is increasingly recognised as a cheap, quick way of producing a therapeutic.
Arntzen noted the rising prominence of plant produced therapeutics in scientific literature and predicted that 2009 to 2010 would be a breakthrough period for the technique.
The next stage in development of the norovirus vaccine is to decide on the formulation and dosage to use in clinical trials. Nasal administration is more effective, according to Arntzen, and a formulation using a mucoadhesive is being investigated.
This is a dry powder formulation containing the mucoadhesive that makes the treatment stick to the nasal passages. Patients are unable to feel the powder in their nostrils.
Arntzen described the formulation as “very, very effective” and the intellectual property of the delivery method is now being investigated. Once these stages are complete Phase I trials will begin using funding from the US National Institutes of Health (NIH).
Factors restraining the norovirus vaccine
Norovirus is not life threatening and has limited market potential and this is why big pharma is yet to produce a vaccine for it, according to Arntzen. However, tobacco plant based production could cut costs and make the vaccine economically viable.
The reasoning for this is that norovirus vaccine will probably be purchased by consumers, as opposed to prescribed by doctors, so costs must be kept low.
Arntzen is hoping to manufacture the vaccine at a “reasonable cost” and suggested that the flu vaccine, which costs $15-20 (€11-14), should be used as a benchmark.
Travellers, the military and hospital staff were suggested as potential users of the vaccine, which would provide immunity against the virus that causes diarrhoea and vomiting.