Silence Is No Support for Negative Claim Limitation

| Brian C. BarnesJeremiah S. Helm, Ph.D.


Before Moore, Hughes, and Linn (dissenting). Appeal from the United States District Court for the District of Delaware.

Summary: Silence regarding the presence or absence of a limitation in a patent specification was not sufficient to provide written description support for a negative claim limitation.

Novartis sued HEC for infringement. The patent at issue was directed to a method of treating relapsing-remitting multiple sclerosis by administering the drug “at a daily dosage of 0.5 mg, absent an immediately preceding loading dose regimen.” A loading dose is a higher than daily-dose of the drug, typically given as the first dose. HEC argued there was no written description support for the negative limitation “absent an immediately preceding loading dose regimen.” The District Court disagreed and found Novartis’s patent was not invalid for lack of written description.

The Federal Circuit initially affirmed the District Court’s decision. HEC petitioned for rehearing, which the Federal Circuit granted. On rehearing, the Federal Circuit vacated its initial decision, reversed the District Court’s judgment, and held the patent at issue invalid for lack of written description. The Federal Circuit noted that even for negative claim limitations, silence is generally not sufficient to provide written description support. The Court held that while a negative limitation need not be recited in haec verba, the specification must contain some disclosure that conveys to a person of skill in the art that the exclusion of the limitation was intended by the inventor, such as discussion of the disadvantages or alternatives to the limitation. In this case, the patent’s specification was silent regarding whether a loading dose should or should not be used as part of the treatment regimen. The Court therefore held that the specification failed to adequately describe the absence of a loading dose and concluded that the patent is invalid under 35 U.S.C. §112.

Judge Linn dissented, arguing that the majority applied “a heightened written description standard to the facts of this case in requiring not only a ‘reason to exclude’ but a showing that the negative limitation in question was ‘necessarily excluded.’”

Editor: Paul Stewart