1. “The Importance of Detailed Definitions in Patent Claim Construction”
2. “Key Issues in Claim Drafting for Biotech, Chemical and Pharma Patent Applications”
3. “Understanding the Broadest Reasonable Interpretation (BRI) Standard in Patent Examination”
4. “Strategic Considerations in Drafting Patent Claims”
5. “Interpreting Markush Groups in Patent Claims”
6. “Dependent Claim Invalidation: A Cautionary Tale”
7. “Future Topics in Patent Claim Drafting: Indefiniteness, Product-by-Process Claims, and More”
Understanding Patent Claims and Their Construction
The process of drafting a patent claim is a complex task that requires a deep understanding of patent law and the specific invention at hand. The claim defines the scope of the invention and is crucial in determining whether a patent is granted or not. The construction of a claim during the U.S. Patent and Trademark Office (USPTO) examination of a patent application is based on the broadest reasonable interpretation (BRI) of the claim. However, this standard is not used in Federal Courts or for cases before the International Trade Commission (ITC).
Changes in Claim Construction Standards
Since November 13, 2018, the BRI is no longer the standard for post-grant proceedings before the Patent Trial and Appeals Board (PTAB). Instead, these proceedings rely on the ordinary and customary meaning of the claim term, informally referred to as the “Phillips” standard. Both of these standards are viewed in the context of the person of skill in the art (POSITA) at the time of filing. The USPTO decided to replace the BRI standard for all post-grant proceedings with the federal court claim construction standard in response to comments from stakeholders and as part of the office’s “continuing efforts to improve AIA proceedings”.
Strategic Considerations in Claim Drafting
From a strategic point of view, with respect to drafting claims, the differing claim construction strategies between the USPTO examination process and post-grant and court proceedings probably will not change one’s claim drafting strategies. However, a significant practice point is to provide a significantly detailed definition in the specification for claim terms. While there is always the risk that specifying the definition of a claim in the specification may result in the court adopting a narrower construction than may have been the case if the term was not defined, it is the authors’ view that current trends in multiple areas of patent law favor detailed definitions of claim terms.
Understanding Markush Groups
A Markush-type claim recites alternatives in a format such as “selected from the group consisting of A, B and C.” The members of the Markush group ordinarily must belong to a recognized physical or chemical class or to an art-recognized class. The Examiner must examine all the members of a Markush group in the claim on the merits if the members of the Markush group are sufficiently few in number or so closely related that a search and examination of the entire claim can be made without serious burden.
Interpreting Markush Groups
The Federal Circuit has looked at the issue of how to interpret Markush Groups in several cases. In Multilayer Stretch Cling Film Holdings, Inc. v. Berry Plastics Corp., the court held that the Markush group of element (b) was closed to resins other than the listed four. However, the court held that the Markush group was not closed to blends of the four listed resins. In Shire Development, LLC v. Watson Pharmaceuticals, Inc., the Federal Circuit also looked at the issue of how to interpret Markush Groups. The court found that Watson did not infringe because of its interpretation of a Markush group in the claims.
Dependent Claim Invalidation
The court in Multilayer v. Berry also looked at the issue of whether a dependent claim is proper. 35 U.S.C. §112(d) states that a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers. In Pfizer, Inc. v. Ranbaxy Laboratories Ltd., the court held that dependent salt claim 6 was invalid for failing to further limit its base claim; the base claim was not open to salts.
Future Developments in Patent Law
The fields of patent prosecution and patent litigation are ever-evolving, and with every new court decision there are lessons for patent practitioners. In future blog posts we will cover more claim drafting topics of interest, such as indefiniteness, product-by-process claims, means plus function claims and negative claim limitations.
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Author: microgen