Prosecution History Informs Claim Meaning Even Without Unmistakable Disclaimer

09 January 2018 PharmaPatents Blog
Authors: Courtenay C. Brinckerhoff


The Patents At Issue

The patents at issue were U.S. Patent Nos. 7,790,199 and 7,829,121, which are listed in the Orange Book for Aptalis’s AMRIX® product. The court cited claim 1 of the ‘199 patent as representative:

1. A pharmaceutical dosage form comprising a population of extended release beads, wherein said extended release beads comprise:
an active-containing core particle comprising cyclobenzaprine hydrochloride as the active; and
an extended release coating comprising a water insoluble polymer membrane surrounding said core, wherein said water insoluble polymer mem- brane comprises a polymer selected from the group consisting of …
wherein the total amount of cyclobenzaprine hydrochloride in the pharmaceutical dosage form is 30 mg;
wherein following a single oral administration of the pharmaceutical dosage form, the pharma- ceutical dosage form provides a maximum blood plasma concentration (Cmax) of 19.851±5.8765 ng/mL of cyclobenzaprine HCl and an AUC0-168 of 736.60±259.414 ng·hr/mL.

The highlighted claim language was in dispute. In particular, Apotex argued that its ANDA product did not infringe because it used a matrix-type formulation to achieve extended release, not an extended release coating.

The Federal Circuit Decision

The non-precedential decision was authored by Judge Stoll and joined by Judges Reyna and Wallace.

The district court had construed the claims broadly enough to encompass the Apotex product. On appeal, Apotex argued that the intrinsic evidence showed that “an ‘extended release coating’ is limited to a continuous outer film, not simply ‘[a] layer of any substance that is applied onto the surface of another.’” The Federal Circuit agreed.

First, the court considered the “coating” and “surrounding” language of the claims:

A coating that surrounds the core or encloses it on all sides connotes a continuous coating, i.e., one that covers the entire surface of the core. And, because the extended release coating must surround the core, the plain claim language suggests that the coating must be located outside of the core. In other words, the water insoluble polymer membrane is an outer coating relative to the core. Our construction reflects these limitations by requiring a “continuous outer film applied onto the surface of the active-containing core.”

Then, the court looked to the specification:

First, every embodiment in the specification that discusses a coating describes a process in which the water insoluble polymer coating is external to the active-containing core. ….

And the specification’s frequent references to applying the extended release coating “onto” the active-containing core comports with our understanding of the spatial orientation required by the claims.

Finally, the court considered the prosecution history, and found that an expert Declaration that had been submitted would have led a “person of ordinary skill [to understand] that the extended release coatings of the invention were continuous films” and were “an outer layer relative to the core because the coating is [described as being] ‘deposited onto’ the core.”

The court rejected Aptalis’s argument that “the prosecution history is irrelevant to the claim construction question here because there is no clear and unmistakable disavowal of claim scope.” The court noted instead:

We have stated that “[a]ny explanation, elaboration, or qualification presented by the inventor during patent examination is relevant, for the role of claim construction is to ‘capture the scope of the actual invention’ that is disclosed, described, and patented.” ….  Accordingly, even in the absence of a clear and unmistakable disavowal, we conclude that the prosecution history can be evaluated to determine how a person of ordinary skill would understand a given claim term.”

Know Your Rights

While patent litigation falls squarely on the civil side of the law, patent practitioners would be served well by remembering that anything they say during prosecution can and will be used against them in a court of law.


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