Hi JL -- happy Memorial Day
Another way to summarize the entire point here might be: Judge Du puts a trememdous amount of effort into reverse engineering the perspective of a POSA (or PHOSITA -- a "skilled artisan"), and she claims the POSA would see EPA and DHA, assume one of the two was causing the LDL-C buildup in VHTG patients, and then the POSA concludes it must be EPA since available art leaned in that direction.
Punchline: We don't need to speculate about what a POSA would have thought. The world at that time was lousy with POSAs! And the dichotomy the fake POSA poses never arose at that time. All the actual POSAs believed that the LDL-C buildup was independent of the agent reducing triglycerides. All the actual POSAs said, "It doesn't matter what you use. You can't stop the buildup when trigs are that high -- it's a function of the underlying condition."
Covington made the point -- Du ignored it. Singer reiterates the point powerfully. Will anyone on the Federal Circuit bother to listen?