According to data gathered from the US clinical trials registry for phases II–IV studies between October 2005 and September 2007, six major therapeutic areas accounted for 68% of all protocols and 74% of all sites. In order from most to least activity, these six areas were oncology, central nervous system (CNS) disorders, cardiology, infectious diseases, endocrinology and respiratory diseases. Breast cancer and lung cancer had the most trials, but growth in the number of new studies for each declined. Depression and schizophrenia had the largest number of trials among CNS disorders, but the number of early-phase trials for each decreased, while the number of earlier stage trials for Alzheimer’s disease, multiple sclerosis, sleep disorders and attention-deficit/hyperactivity disorder increased. The number of trials for leading cardiology disease, such as hypertension, and for infectious diseases also declined. In endocrinology, diabetes had 356 new trials, the most for any disease in any therapeutic area for the period analyzed. The therapeutic areas with the highest percentage growth in protocols were rheumatology (158%) and kidney/urology (121%). Ophthalmology (164%) and rheumatology (111%) showed the highest percentage growth in trial sites.

Source: Nature