Waterfall Disputes in Stacked Royalty Deals: When Multiple Holders Go to War Over the Same Revenue Stream
In April 2022, a Texas jury needed two hours to decide that Daiichi Sankyo owed Seagen $41.8 million in back royalties on Enhertu — plus an 8% running rate on all future US sales of what was already a multi-billion dollar oncology franchise. Three years later, the Federal Circuit reversed