Table 1.

Tiered Labeling Framework for Development of Antibacterial Agents^a

Tier	Typical Efficacy Database	Typical Label Wording
A	Two phase 3 trialsb in infection Y; additional indications can be added after single phase 3 studies	Drug X is indicated for treatment of infection Y when proved or strongly suspected to be caused by drug X–susceptible strains of [list of pathogens]
B	One phase 3 trialb in infection Y, plus small prospective studies and descriptive data focused on the tier C pathogen(s) in a range of standard infections	Drug X is indicated for treatment of infection Y and [list of studied infections from tier C database] when proved or strongly suspected to be caused by drug X–susceptible strains of [list of pathogens]; because data for drug X in these infections are limited, drug X should be used only if other alternatives are known or suspected to be less suitable
C	Small prospective studies and descriptive data focused on the tier C pathogen(s) in a range of standard infections	Drug X is indicated for treatment of [list of studied infections from tier C database] when proved or strongly suspected to be caused by drug X–susceptible strains of [list of pathogens]; because data for drug X in these infections are limited, drug X should be used only if other alternatives are known or suspected to be less suitable
D	Animal studies	Drug X is indicated for the emergency treatment of infection Y caused by susceptible strains of organism Z; drug X should not be used for infection Y unless other options are unavailable

^aSource: Rex et al [12].

^bThese trials should meet standard requirements for disease definitions, end points, and statistical design elements.