Which statement is false regarding orphan drug designation in the US?

The statement regarding orphan drug designation in the U.S. that is false is that once designated, the drug receives automatic approval. While receiving orphan drug designation offers various incentives, including tax credits and market exclusivity, it does not guarantee that the drug will be approved by the FDA. The drug still must undergo the full regulatory review process and meet efficacy and safety standards before it can be approved for marketing.

The other statements accurately reflect aspects of the orphan drug designation process. The encouragement for sponsors to request designations for pediatric subpopulations aligns with the FDA's priority to address health needs in children, who often have limited treatment options. The incentive structure provided by orphan status is meant to promote the development of drugs for rare diseases, helping to balance the challenges of conducting research in small patient populations. Lastly, the requirement of evidence of a small patient population is a key criterion for receiving orphan drug designation, as the designation itself is designed for conditions affecting fewer than 200,000 people in the U.S.