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October 28, 2009

Virus Like Particle Vaccine Trials and Other Paths for Faster Vaccine Development

Viruses and Vaccines are in a race. Two new flu vaccine candidates beginning clinical trials this month, the "virus-like particle," or VLP, vaccine may be about to fulfill a long-heralded potential as a flu vaccine that arrives more quickly. From MIT Technology Review and Forbes.

VLP vaccines can be made quickly. "From the time you identify an outbreak and publish the genetic sequence online, you can have a vaccine in full production within three or four months," says Ted Ross, a microbiologist and geneticist who researches VLPs at the University of Pittsburgh's Center for Vaccine Research. This offers a huge improvement over the present approach, which has struggled to produce a vaccine for H1N1 in seven months. It's also fast enough to check a flu pandemic before it switches hemispheres--as the swine flu did when it followed the winter from the north to the south this past May and June.

VLP flu vaccines have moved onto the fast track, and VLP vaccines have done well in animal trials against avian, swine, and seasonal flu, and against Ebola as well. Now two of the leading developers, Novavax, of Maryland, and Medicago, of Quebec City, have taken VLP flu vaccines all the way through preclinical animal testing and into human clinical trials, two of which are beginning this month.




Medicago grows its VLPs in transgenic tobacco plants, which are simple to manipulate, fast to grow, and easily raised in high-tech greenhouses that can be built almost anywhere. The company injects full-grown tobacco plants with genetic information from a target virus, and the plants produce VLPs in their biomass that can be extracted a few weeks later. Novavax uses an insect cell-culture approach, growing its VLPs in a line of identical "immortalized" cells taken 20 years ago from a caterpillar called a fall armyworm. The armyworm cells are injected with a recombinant baculovirus--a virus that only infects insects--that is tweaked to resemble a targeted flu virus. The cell responds by producing and secreting VLPs that have a shell identical to that of the flu virus but contain no flu RNA.

Both processes are relatively cheap and fast. To illustrate, the 400-person phase I clinical trial of Novavax's swine flu vaccine candidate that began in Mexico this week was developed from the genetic information released on the H1N1 virus in early May and has already been through the design, small-scale production, and animal testing phases. Over this same time span, conventional makers have just barely started making the first deliveries of a vaccine that required no fresh design, no animal testing, and only minimal human testing.


VaxInnate, a closely held biotech firm, is working on technology that could derive in only six weeks a new vaccine for the H1N1 swine flu, the virus causing the global scare. Then, in the space of a month, it could turn out 2 billion doses--surpassing the annual production capacity of all flu-shot makers combined. The work is still five years away from possible large scale deployment.

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