Shares of BioCryst Pharmaceuticals slid about eight percent on the news that it wants to expand the size of its late-stage study of its IV formulation of peramivir while altering the endpoint. The trial revisions would extend the projected time it will take to enroll all the patients it needs past the end of this year, breaking a self-imposed schedule. Researchers want to compare patients who get the drug with patients who have not been treated with neuraminidase inhibitors. Story