A new drug can be said to fulfill an unmet medical need if it addresses a condition whose treatment or diagnosis is not adequately addressed by existing treatments. This can mean that the drug treats a condition for which no other treatment exists, or that it confers some benefit that existing treatments do not (e.g., new or improved effect on a treatment outcome, decreased toxicity, or fewer interactions with other drugs). New drugs with the potential to fulfill unmet medical need can qualify for expedited approval mechanisms due to their outsized potential to benefit patients.