In our situation, we have found pulmazyme not to really have any effect one way or the other so far. My daughter has been on it about 5 months and perhaps it's too early to see results. Her PFT is at remain about 97-99. She has not experienced any mucous or coughing. I just read an article on a study about air trapping in mild cases of CF and it sounds like Pulmazyme does help even in mild cases or high PFT numbers. For what it's worth, here is the site. <a target=_blank class=ftalternatingbarlinklarge href="http://www.chestjournal.org/cgi/reprint/128/4/2327.pdf">http://www.chestjournal.org/cgi/reprint/128/4/2327.pdf</a>