If Vascepa Plus is a new patent formulation for CVD-ONLY and/or DIABETES/CVD-ONLY, it not only is new formulation (look at the claims section), it would be patent protected, and yes, Amarin would need to conduct a clinical study. But that said, this could be of equal interest to a BO since it adds significant value to the life-cycle.
Something needs to made clear here: Vascepa PLUS is not Vascepa -- just compare the formulation. It is a next generation drug.