Courts continue to remind patent owners and patent practitioners that when it comes to patent drafting, the specification is just as important as the claims, if not more

The claims of a patent define the scope of the invention and provide the metes and bounds of patent protection afforded under the patent. Therefore, often people pay more attention to the claims of the application than the text of the specification. But what is claimed must also be disclosed in the specification of the patent. “The claim or claims must conform the invention as set forth in the remainder of the specification and the terms and phrases used in the claims must find clear support or antecedent basis in the description so that the meaning of the terms in the claims may be ascertainable by reference to the description.”  37 C.F.R. § 1.75(d)(1).  In addition, the claims can be amended during prosecution of the patent application, but the specification can rarely be changed.  Therefore, it is essential to make sure that the invention is described to the fullest extent possible in the specification before the patent application is filed.

A carefully drafted specification becomes even more important if the patent is ever asserted or challenged in a patent litigation. While the granted patent claims will take center stage, the specification of the patent will provide a very important supporting role in determining the meaning of any disputed claim term.  See, e.g., Phillips, 415 F.3d at 1315 (Fed. Cir. 2005) (“the specification ‘is always highly relevant to the claim construction analysis.  Usually, it is dispositive; it is the single best guide to the meaning of a disputed term.”).  And the courts continue to remind patent owners and practitioners of the importance of a well-drafted patent specification, See e.g., Genentech, Inc. v. Aurobindo Pharma Limited, No. 19-cv-78-RGA (D. Del. Oct. 20, 2020).

In Genentech, Inc., the U.S. District Court of Delaware held that the claim term “Grade 2 abnormality in one or more biomarkers of liver function,” as recited in the three asserted patents, is not indefinite. As a reminder, for considerations of indefiniteness, “a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”  Id., at p. 2 (quoting Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 901 (2014).

The plaintiffs argued that “one or more biomarkers of liver function” is defined in the specification as the five biomarkers alanine transaminase (ALT), aspartate transaminase (AST), bilirubin, alkaline phosphatase (ALP), and gamma-glutamyltransferase (GGT), and contended that the specification consistently identified “Grade 2 abnormalities” with respect to only to these five biomarkers (citing to tables provided in the asserted patents).  Id., at p. 4.

The defendants, however, argued that “Grade 2 abnormality in one or more biomarkers of liver function” is indefinite because the phrase has no plain and ordinary meaning and neither the claim language nor the specification indicate the outer boundary of the term. Id., at p. 4 (citing to several instances in the specification where, “biomarkers of liver function” is allegedly unclear or self-contradictory).  Id., at p. 4.

The court disagreed with the defendants and stated that the patent claims require a “Grade 2 abnormality” and only the five tests—ALT, AST, bilirubin, ALP, and GGT—are defined in the specification as terms of the requisite elevation levels that would constitute such a “Grade 2 abnormality.” Id., at pp. 5-6. Therefore, the court concluded that “[t]he term ‘Grade 2 abnormality in one or more biomarkers of liver function’ read in light of the specification and claims reasonably informs a person of ordinary skill in the art as to the scope of the disputed claims and is therefore not indefinite.” Id., at p. 7.

The order in Genentech is another reminder of the importance of a carefully drafted specification and how the terms used, and statements made, in the specification may later affect claim construction. Claims containing inconsistent terms can cause unintended consequences in a patent litigation.  Consequently, patent practitioners should strive to consistently and clearly use terms when describing the invention in the specification and claiming the invention in the claims.  A careless mistake, no matter how small, innocent, or seemingly trivial may have a big impact on the outcome of a patent litigation.