The drug lag revisited: comparison by therapeutic area of patterns of drugs marketed in the United States and Great Britain from 1972 through 1976.

This study describes rates and patterns of new drug introductions in the U.S. and Britain from January, 1972, through December, 1976, updating an earlier study that described the patterns over the previous decade. This comparative international approach enables overall effects of different regulatory, industrial, and other types of changes in drug research and development in the two countries to be evaluated. Numerical differences persisted. In the 1972 to 1976 period, 82 new drugs appeared for the first time in either country. Only 29% of these became mutually available in both countries, 2.4 times as many becoming available first in Britain as in the U.S. Of the 71% that became exclusively available, 2.6 times as many became available in Britain as in the U.S. More important than numerical data are clinical implications of differences between the countries. The largest differences have narrowed since the previous study, but important categories in which the U.S. still lagged behind Britain in December, 1976, included cardiovascular drugs, peptic ulcer drugs, and central nervous system drugs--including therapies for depression, epilepsy, and migraine. Several factors contributed to the narrowing of U.S.--British therapeutic differences, including more realistic regulatory practices and higher quality clinical studies in the U.S., more conservative practices in Britain, attention drawn by previous studies to anachronisms in the U.S., and industrial changes such as more efficient penetration of the U.S. market by foreign firms. It is difficult to determine the relative contribution of each of these factors to the narrowing of the international difference.