As Rare Disease Day approaches, there's plenty to celebrate. The acquisition of Baxalta Inc. by Shire plc early in 2016 created a global giant with an equally large appetite for therapies to treat rare indications. Last year saw a huge, albeit controversial, breakthrough to treat Duchenne muscular dystrophy (DMD) with accelerated approval of Sarepta Therapeutics Inc.'s exon-skipping drug, eteplirsen, branded Exondys 51. And as the year ended, passage of the 21st Century Cures Act – encompassing patient-focused drug development, qualification of biomarkers and other development tools, and novel clinical trial designs – became a legislative triumph for the rare disease community.