Biological patent thickets and delayed access to biosimilars, an American problem.

Our study seeks to determine whether patent thickets covering biologic drugs are responsible for delayed biosimilar market entry. We compare patent assertions against the same biosimilar drugs across three countries. On average nine to twelve times more patents were asserted against biosimilars in the United States than in Canada and the United Kingdom. Biosimilars also enter the Canadian and UK markets more quickly than they do in the United States following regulatory approval. Later market entry is not a problem when the brand name drug company is asserting high quality patents (i.e. patents covering significant advances). Consequently, we drilled down into the U.S. patent portfolio of one major biologic, Abbvie's Humira drug, and found that it was made up of roughly 80% non-patentably distinct (duplicative) patents linked together by terminal disclaimers, which is permitted under United States Patent and Trademark Office (USPTO) rules. In contrast, there were far less non-duplicative European patents that covered Humira. Patent thickets can allow brand name drug companies to delay biosimilar entry by relying on the high cost of challenging many duplicative patents instead of the quality of their underlying patents. Accordingly, we suggest several policy interventions that may thin these biologic patent thickets.