We discussed drug therapies for the viral families and their associated diseases today in the review section. I asked the question of whether or not the FDA has a threshold in their risk-benefit analysis that if surpassed will keep a drug off the market. The answer was that it doesn’t; whether or not a new drug is approved depends on the severity of the disease in respect to the(side) effects of the drug. A drug for rabies with toxic effects can be approved, while a drug for the common cold with the same toxic effects would not.
A recent article in Scientific American considers the prospects of drugs and vaccines for the common cold. It discusses the anticold drug pleconaril. After impressive results in cell culture it was proclaimed “the magic bullet” and “the Holy Grail.” However upon use in humans it reduced the length of colds by one day. It also caused women to bleed between menstrual periods and interfered with hormonal birth control (several women actually got pregnant during the trial). When considering whether or not to use pleconaril, it turns out it is better to suffer through the common cold.
A proper drug must be “as safe as water” because the common cold is not a life-threatening disease. Regarding anticold drugs, they must be “very effective, absolutely cheap, and completely safe.” In fact recent evidence suggests that rhinoviruses may be beneficial for human health. In France, the number of H1N1 cases increased as the number of rhinovirus cases decreased in 2009. Perhaps the common cold may prime the immune system to be more protective against other more serious illnesses.
Attempts at targeting the virus itself and eliminating infection have proved fruitless. A new strategy may be to target the body’s immune/inflammatory response, the reason behind common scold symptoms. In about 1/3 of rhinovrius infections the infected individual does not show symptoms, so the inflammatory response is not necessary for the elimination of the virus. But again, by hampering our own immune systems we may trade the inconvenience of a common cold for more serious side effects or illnesses.
|The number of H1N1 cases increases as the number of rhinovirus cases decreases.|
2009 H1N1 pandemic data in France