Limbrel was first marketed nationally in April 2004. At that time, no instances of hypersensitivity pneumonitis had been reported in clinical trials or test marketing surveillance. By 2008, three cases had been reported, and the package insert was revised to reflect this complication. At the time of its most recent revision, in mid-2010, the package insert was again revised to reflect seven confirmed cases reported in post-marketing surveillance and through the US Food and Drug Administration’s MedWatch. As of that time, approximately 270,000 people had been exposed to the product as judged by the number of new prescriptions filled. Thus, the apparent incidence of hypersensitivity pneumonitis, as nearly as we can estimate it, is approximately 0.0023%, or somewhere around two to three per 100,000.