Reformulations are changes in a drug’s “molecular formulary,” including any combination of changes in active ingredient concentrations, inactive components, or changes in the means of drug delivery. When drugs that have been FDA-approved are reformulated, the data used for the original approval can often be used to support the new application (examples appear in Table 1). In this way reformulation can represent a shortcut past some regulatory hurdles faced by drugs classified as NMEs. While patent protection is certainly a factor in the prevalence of reformulations, improvements in therapeutic efficacy are the overriding motivator. Often these improvements are the result of knowledge of a drug’s properties gained following approval, when the number of patients (and physicians) with first-hand experience grows from clinical-trial levels to tens of millions.
