Takeaway: It is more important than ever to review patent applications during research and development to ensure that the key invention is fully covered.

The U.S. Court of Appeals for the Federal Circuit recently invalidated two separate pharmaceutical patents (Indivior’s opioid addiction treatment Suboxone and Biogen’s multiple sclerosis drug Tecfidera) for not meeting the requirement that patents must have a “written description showing the inventor possessed the invention as of the filing date.” The Federal Circuit said the law requires “a statement of an invention, not an invitation to go on a hunting expedition.”

In the Indivior case, the patent described the invention as a film, approximately 40%-60% of which is a water-soluble polymeric matrix. The Federal Circuit said that specific range was not found in the original patent application, which opted to use phrases such as “at least 25%.”

In the Biogen case, the patent claims describe treating multiple sclerosis (MS) with 480 mg of a specific drug, but the Federal Circuit similarly said that dose was not adequately described. The court found that while a “single passing reference” to that number was included in the written description, it was a part of a wide range of doses that did not indicate that 480 mg was the effective dose.