Regulatory approval characteristics of antimicrobial versus non-antimicrobial products, 1984–2018: an evaluation of Food and Drug Administration flexibilities

Antimicrobial resistance is of growing concern. To encourage development of new treatments, some commentators have suggested regulators exercise increased flexibility on the clinical evidence required for approval. We examined all 1065 new drugs and biologics approved by the US Food and Drug Administration between 1984 and 2018 and recorded each drug's use of the Orphan Drug Act, fast-track, priority review, accelerated approval, and breakthrough therapy programmes, as well as dates of investigational new drug application, new drug application, and new drug approval, which were used to calculate clinical development and review times. There were 178 (17%) antimicrobial products, which were more likely than non-antimicrobial products to benefit from priority review (103 [58%] of 178 vs 402 [45%] of 887, p=0·0023), fast-track designation (58 [37%] of 157 vs 151 [19%] of 814], p<0·001), and accelerated approval (23 [18%] of 129 vs 67 [9%] of 711, p=0·0046), and less likely to have Orphan Drug Act designation (25 [14%] of 178 vs 267 [30%] of 887, p<0·0001). Median time from investigational new drug application to approval was shorter for antimicrobial than for non-antimicrobial drugs (5·9 years [IQR 4·6–7·3] vs 7·6 years [IQR 5·7–10·2], p<0·001). Except for Orphan Drug Act status, expedited clinical testing and review programmes have been used at least as frequently for antimicrobial products as for non-antimicrobial drugs. No evidence supported claims that antimicrobial progress through the regulatory approval process in the USA is more time-consuming than non-antimicrobial development.