Protein Grown in Tobacco Plant Could Result in Low-Cost Microbicide

Researchers on Monday announced that tobacco plants in Kentucky have been used in a study to develop a low-cost drug that inhibits HIV, providing hope for the eventual development of a vaginal microbicide, the Louisville Courier-Journal reports (Kenning, Louisville Courier-Journal, 3/31). The study, published Tuesday in the Proceedings of the National Academy of Sciences, was a collaborative effort between scientists at the Owensboro Cancer Research Program; the National Cancer Institute; Kentucky-based biotech companies Intrucept Biomedicine and Kentucky Bioprocessing; and researchers at Duke University and the University of London (Adkins, Business First of Louisville, 3/30).

According to the Courier-Journal, the researchers used a manufacturing process that utilized an existing protein called Giffithsin, which can inhibit HIV transmission during sexual activity. Kenneth Palmer, lead researcher and senior scientist at the University of Louisville, said that he used a method to grow large amounts of the protein in a relative of the tobacco plant at a low cost, producing 500,000 doses from a 5,000 square-foot greenhouse, the Courier-Journal reports. Palmer said the process resulted in a product that could be more effective than previous microbicide efforts.

According to Palmer, many scientists are pursuing HIV prevention methods, mostly in gel forms that attack the virus, but some have had side effects and were expensive to produce. The Courier-Journal reports that Palmer's product did not appear to cause inflammation in users and that a vaginal gel made through the process "could potentially cost just a few cents." Palmer said that the end-product, likely a gel, could be available as early as 2015 if clinical trials are successful (Louisville Courier-Journal, 3/31). He estimated that "tens of millions" of dollars would be needed to continue the project through the third phase of clinical testing. Donald Miller, director of the James Graham Brown Cancer Center, said that international donors might be interested in assisting in funding the research. Miller said the new study is a "very important piece of work." He added, "We think this is a validation of our belief that this is going to be a very viable, cost-effective way to produce new drugs" (Business First of Louisville, 3/30). According to Palmer, condoms are the only product currently available and "they're obviously not enthusiastically embraced by all users." He added that there is "a big need for an effective, female-controlled intervention to protect from HIV" (Louisville Courier-Journal, 3/31).