FDA advisory committees and the new drug approval process.

To determine the impact of FDA advisory committee review on the approval time of new drug applications (NDAs) approved during the five-year period 1983 through 1987, we compared NDA phase lengths of reviewed new chemical entities (NCEs) with those that were not reviewed and examined the elapsed time from final committee recommendation for approval to NDA approval. Of the 95 drugs approved during the study period that met the Center for the Study of Drug Development's definition of an NCE, 40 (42%) were submitted for review--mean NDA phase length was 36.9 months versus 32.4 months for unreviewed drugs. Reviewed drugs in the neuropharmacologic division had a longer NDA phase, while those in the metabolic/endocrine and oncology/radiopharmaceutical divisions had shorter NDA phases, than unreviewed drugs in those divisions. For NCEs grouped by therapeutic rating, reviewed drugs in each category had longer NDA phases than unreviewed drugs; the difference was largest for 1-B rated drugs. The elapsed time from committee recommendation for approval to NDA approval as a percent of the total NDA phase was greatest for drugs submitted by the metabolic/endocrine division (83.0% of NDA phase) and for drugs rated 1-A (63.2%). Results indicate that advisory committee review is associated with a small overall delay in NDA approval when compared with the regulatory fate of drugs not submitted for review.