Does Drug Repurposing Lead to Faster FDA Approval? Evidence from New Drug Applications, 1990–1999

Abstract

Drug repurposing has gained interest as a faster, cheaper path than traditional drug development, with industry claims of up to 85% lower costs and five years shorter timelines. Yet direct evidence that repurposed drugs obtain regulatory approval faster is scarce. This study fills that gap by comparing approval times for repurposed versus non-repurposed drugs using FDA Drugs@FDA data. This study examines 289 Type 1 new molecular entity NDA submissions from 1990 to 1999, of which 148 had full approval-duration records. The main analysis uses negative binomial regression, with OLS on log-transformed duration as a robustness check, and controls for review priority, submission year, and marketing status. Repurposed drugs averaged 538 days from submission to approval, while non-repurposed drugs averaged 609 days, a 71-day advantage for repurposing. However, bivariate tests and regression models did not find this difference statistically significant. The key finding is institutional: submission year, reflecting the effect of the Prescription Drug User Fee Act of 1992, is the strongest predictor of approval time, with each later year linked to about an 18% shorter duration. After accounting for this time trend, the repurposing status adds little explanatory power. The study concludes that any theoretical time savings from repurposing do not clearly appear at the regulatory approval stage in this sample, implying that efficiency gains likely occur earlier in development before submission.