New indications for already-approved drugs: an analysis of regulatory review times

A survey of the U.S. pharmaceutical industry was conducted to obtain data on the length of the review process for supplemental indications of already-approved new chemical entities (NCEs). Responses were received from 51 firms and covered supplemental indications of 348 NCEs that were approved during 1963 to 1988. Since extensive toxicity and safety evaluation would generally not be required for supplemental indication reviews, one would expect supplemental indications, on average, to be reviewed more quickly than applications for the associated original indications. The mean +/- standard deviation review time for the 172 supplemental indications in the sample is 21.5 +/- 18 months; the average review time for the associated 94 original indications is 23.5 +/- 18 months. The difference in average review times is not statistically significant. Analysis of review times for indications grouped by Food and Drug Administration (FDA) reviewing division showed a statistically significant difference between supplemental and associated original indication review times only in the cardio-renal division. In that division, average review times were longer for supplemental indications (25.6 vs. 19.3 mo; P less than .05). Analysis of time trends showed a significant increase in average supplemental indication review time for 1985 to 1988 approvals relative to the average associated original indication review time (P less than .01) and to average supplemental indication review time for earlier time periods (P less than .01). These results suggest the need for a close examination of the supplemental indication review policy of the FDA.