Knowing drug companies, it has to be more than just filtered fish oil, probably combined with a drug. They can not patent just filtered fish oil. Yes, I've seen the TV commercials. There is an Ethyl Ester form, in fact a person used to post here about 4-5 years back, Ann-Marie, used to push her High quality Fish Oil here quite often. And her product is IFOS rated, as well. It is an Ethyl Ester form I believe, and supposedly absorbed better or something. The product she resells is made in and shipped from Canada.
EDITED: Correction, I looked up her website, I had it the other way around, most fish oils are ethyl esters, while hers is triglyceride based. So that part of the commercial is using the common form of fish oil and making it sound like it is special! Typical advertising.
From her website:
Our Omega-3 PGFO is a highly concentrated triglyceride base fish oil that uses only the finest quality raw materials of fish oils from ocean fish like anchovies, mackerel and sardines. The oil is then put through an exclusive 6-step manufacturing process for extracting the Omega-3s from the fish oil and refining them. In numerous studies, the absorption of Omega-3 fatty acids in their natural triglyceride form are superior to the synthetic ethyl ester form that is common in other concentrated Omega-3 products.