Some time back, Congress decided to do something to support pediatric research. A recurring problem is that drug companies do not do clinical trials of drugs in children, and so pediatricians have to more or elss guess what doses to use based on adult trials. This occurs because the sales in the pediatric age group might not be great enough to provide an incentive for extending the drug's FDA-approved label to kids. Thinking that the industry needed a carrot, Congress passed a law that allowed a 6-month patent extension on the drug for doing appropriate pediatric research.
Critics of the industry, like Marcia Angell (The Truth about the Drug Companies) charge that Congress miscalculated, and that the value of the 6 months of extra patent protection is now so high that companies are testing drugs that will never realistically be used in kids, just to get the extra patent life.
A recent example of this seems to be the following news release:
Arimidex is currently approved by the FDA for use among post-menopausal women in treating breast cancer. AstraZeneca was very happy to announce that it has received an extra 6 months of patent protection due to their conducting pediatric research. Apparently the company decided that maybe conditions in kids that result from excess estrogen, such as breast enlargement in pubertal boys, might be helped by the drug. After doing the research, said the company, they concluded that they would not seek any FDA approval to use the drug in children, after all. (Surprise.)