Whoa, guys, I'm afraid this study is still just highly exploratory.
It looked only at isolated cells taken from the noses of four people with double deltaF508 CFTR, one person with deltaF508/4016ins, and one person with non-deltaF508 CFTR mutations (R1283M/E60X). The cells were treated <u>in the test tube</u> with the active ingredient in Viagra. In all cases, the drug treatment appeared to move the CFTR from the inside of the cell, where defective CFTR often seems to get hung up, toward the exterior membranes, where it is needed to form chloride channels. In one cell culture from a double deltaF508 individual, the treated cells also showed evidence of increased CFTR chloride transport.
So, whatever the effect is, there is some reason to believe it can occur in the cells of people who have either one or two deltaF508 mutations or a R1283M mutation. But there's no way of telling yet whether the changes measured would be enough to correct CF symptoms. Also the concentrations of drug the researchers used were 1,000 to 1,500 times larger than the standard dose you would get from taking Viagra. So the conclusion of the study is not that we should try giving Viagra to people with CF, but that here is a class of drugs that might have promise as a treatment somewhere down the line -- if chemical modifications can produce a version more effective at kick-starting the defective CFTR protein. Finally, it's important to keep in mind that the study was funded in part by Pfizer Pharmaceuticals, which markets Viagra.
Although it isn't yet ready for prime time, this is an intriguing approach, and it's worth keeping our eyes open for any follow-up. Thanks so much, Luke, for letting us know about it.
Bambi, mom of Jordan 16 w cf
