To ring the register, a pharmaceutical company may create a patent thicket, which involves filing dozens of patents that, in some cases, add little value to their medicines but extend precious monopolies. And one crucial, but little-known tool for making this happen is something called a terminal disclaimer.
In short, a terminal disclaimer is a stipulation provided to the U.S. Patent & Trademark Office that a continuation or follow-on patent – essentially, a minor patent that makes few substantive changes to a medicine – will expire at the same time as the original patent filed by a pharmaceutical company. By doing so, a drugmaker can circumvent prohibitions on awarding more than one patent for an invention.
As a result, a drug company can quickly add a number of patents that can be used to protect its medicines from would-be rivals. How so? As patents pile up, companies that want to sell generic or biosimilar versions of these medicines find themselves fighting longer and more expensive patent infringement lawsuits that are designed to delay their plans.