RMB, in this case, it's a little unique. The situation I mentioned is more typical of when the generic product sells for REAL cheap, and the PBM doesn't make much money on it.
I only highlighted it to point out the fact that sometimes the "list" price is not the whole story with generics vs. brands and how PBM's look at them.
There may be other situations where they give preference to generics. For example, if a big generic manufacturer gives a PBM a "bulk" discount on multiple drugs. This is where Amarin would have trouble competing - we only have one drug. Companies like Hikma, DRL, Teva, etc. may have hundreds. So they can afford to offer some "loss leaders" to PBM's to get more business.