In the current of era of developing antibacterial agents, including those for unmet medical need, Sponsors are required to submit a robust pre-clinical pharmacokinetic–pharmacodynamic (PK–PD) data package in exchange for limited clinical data. However, the clinical data package also needs to be as robust as possible. The clinical data package needs to include the Phase 1 pharmacokinetic (PK) studies conducted in the target patient populations and special populations. Additionally, PK data need to be collected from all patients enrolled in the pivotal trial(s). Such data are critical to confirm adequate drug exposures relative to non-clinical PK–PD targets for efficacy, explain unexpected clinical failures in individuals or groups of patients, and evaluate exposure–response relationships for safety.