(Aaron Hakim, Ravi Gupta and Joseph S. Ross, 11/13) JAMA: Pediatric Exclusivity And Regulatory Authority: Implications Of Amgen V. HHS In May 2017, the US Food and Drug Administration (FDA) denied a 6-month extension of market exclusivity for Sensipar (cinacalcet), a drug manufactured by Amgen to manage hypercalcemia, common among patients with end-stage renal disease who are undergoing dialysis. The FDA determined that Amgen's pediatric studies had been conducted inadequately and had provided inconclusive safety data. Amgen brought a lawsuit, Amgen v HHS (US Department of Health and Human Services), to challenge the denial. If Amgen prevails, it can delay generic competition for 6 months for a drug that generated $1.24 billion of revenue in 2016.2 More broadly, a decision favoring Amgen could diminish the FDA's ability to encourage clinically meaningful pediatric studies and thus undermine the purpose of Congress in offering patent extensions to reward pediatric research.