Orphan Drug Royalties: The Economics of Small Populations in Pharmaceutical Royalty Financing
In December 2025, Royalty Pharma agreed to pay $275 million for a 9.25% synthetic royalty on Denali Therapeutics' tividenofusp alfa—a treatment for Hunter syndrome, a lysosomal storage disorder affecting roughly 2,000 patients in the United States. The deal carried a 3.0× cap multiple, with an