William Blair analyst Tim Lugo views BioMarin's (BMRN) favorable Patent Trial and Appeal Board decision over Sarepta (SRPT) as "more than impact." Sarepta will appeal the decision to the U.S. Court of Appeals for the Federal Circuit and the Patent Office will not issue the allowed claims until the appeal is completed, the analyst points out. He says that if in several years BioMarin wins the appeals and its U.S. patents are able to block Sarepta's eteplirsen from the U.S. market, this will come much later than an eventual FDA approval decision. At that time, BioMarin attempting to pull eteplirsen from the U.S. market would be a nonstarter, Lugo tells investors in a research note. Rather, he believes that if Sarepta were to ultimately lose interference proceedings, it would likely need to pay BioMarin a double-digit royalty on eteplirsen sales in the worst-case scenario. The analyst keeps an Outperform rating on Sarepta with a $52 price target.