The written description requirement for CIP claims is not satisfied when the original specification failed to demonstrate constructive possession of the invention, and instead merely recited the problem and a claim to all possible solutions.

The patentee sued for infringement of a patent involving antibodies to human tumor necrosis factor-α involving both a variable region and a constant region for the antibody. After a jury trial, the alleged infringer moved for judgment as a matter of law on non-infringement and invalidity. The district court denied the motion for judgment as a matter of law, and the alleged infringer appealed. The Federal Circuit reversed and held that the patent was invalid for failure to comply with the written description requirement.

The written description requirement is satisfied if the patent applicant conveys “with reasonable clarity to those skilled in the art that, as of the filing date sought, he or she was in possession of the invention, and demonstrates that by disclosure in the specification of the patent.” Considered objectively, the four corners of “the specification must describe an invention understandable to [a person of ordinary skill in the art] and show that the inventor actually invented the invention claimed.” In other words, the specification must demonstrate that the inventors possessed the invention and not merely recite a problem and a claim to all possible solutions.

Here, the patentee alleged infringement of claims added through a continuation-in-part application. To warrant the priority date of the original application, the patentee had to show that the specification and not the later added claims satisfied the written description requirement. The patent specification described a mouse variable region and a human constant region of the antibody. This specification was not sufficient to satisfy the written description requirement for a fully human antibody including both a human variable region and a human constant region. In particular, the specification did not describe any antibodies satisfying the claim limitations. The specification also did not identify any of the characteristics of a fully human antibody or disclose the relationship between a mouse variable region and a human variable region. Finally, the only expert testimony was that the specification would not disclose to a person of ordinary skill in the art how to make a fully human antibody. Thus, the patent failed to satisfy the written description requirement, and the patent was invalid.

A copy of the opinion can be found here.