Even Without a Lexicography One Term May Have More Than One Meaning

Bernadette McGann | May 29, 2013

Title: Even Without a Lexicography One Term May Have More Than One Meaning

Author Name:  Bernadette K. McGann

Case Name:  Aventis Pharmaceuticals Inc. v. Amino Chemicals Ltd.

Key words:  Claim Construction, Intrinsic Evidence, Prosecution History

Decision Date: May 20, 2013

CAFC Panel and opinion author:  Newman, Bryson and Reyna.  Opinion by Reyna.  Dissenting opinion by Bryson

Summary

The claim in dispute recites a process of preparing a piperidine derivative compound that included providing a substantially pure regioisomer of a specific formula.  The District Court construed the meaning of “substantially pure” in relation to an intermediate compound to mean 98% purity, which is the same meaning as “substantially pure” when in relation to the piperidine derivative end product.  The CAFC reversed the “one construction throughout the patent” rule, adopted by the District Court.

Details

Dr. D’Ambra developed and patented an improved method of achieving substantially pure piperidine derivative end product, which is an active ingredient in antihistamine medication.  U.S. Patent No. 5,750,703 (hereinafter ‘703) was eventually assigned to Sanofi-Aventis in an exclusive license.  Claim 1, the only independent claim, of ‘703 recites:  A process of preparing a piperidine derivative compound of the formula:

may-29-cafc-blog-image-11-crop

wherein Rl is hydrogen or hydroxy; R2 is hydrogen; or Rl and R2 taken together form a second bond between the carbon atoms bearing Rl and R2; R3 is -COOH or -COOR4; R4 has 1 to 6 carbon atoms; A, B, and D are the substituents of their aromatic rings, each of which may be different or the same, and are selected from the group consisting of hydrogen, halogens, alkyl, hydroxyl, alkoxy, or other substituents,

said process comprising:

providing a substantially pure regioisomer of the following formula:

may-29-blog-image-22-crop

converting the substantially pure regioisomer to the piperidine derivative compound with a piperidine compound of the formula:

may-29-cafc-blog-image-31-crop

The substantially pure regioisomer, a cyclopropylketone (CPK) intermediate, is a novel feature of the ‘703 method.  The CPK intermediate may exist in one of two regiosiomeric (chemical compound with same chemical formula but different bonding order) forms.  The para‑CPK is biologically active while meta-CPK is biologically inactive.  While in the prior art poor yields are achieved due to the impure mixture of meta and para-regioisomers, the ‘703 patent achievessubstantially pure para-piperidine derivative end product due to the para/meta CPK regioisomeric mixture being more readily separable to obtain para-CPK.

Aventis filed suit against several generic drug manufacturers in the New Jersey district court, alleging, inter alia¸ infringement of the ‘703 patent after an ANDAs (abbreviated new drug application) was submitted to the FDA.

The specification discloses “substantially pure piperidine derivative” and “substantially pure regioisomer” but does not define either term.  After a Markman hearing, the District Court held that the specification and the claims did not give sufficient guidance as to the meaning of the claim term “substantially pure”.  The District Court held that “because the specification uses the same term consistently for both intermediates and derivatives, the Court finds that what ‘substantially pure’ means when it modifies the piperidine derivative applies equally to its context in the claims’ ‘substantially pure regioisomer of the formula’.”

The District Court looked to the prosecution history of related U.S. Patent No. 5,578,610 (hereinafter ‘610), a divisional application that descended from the same parent application as ‘703, to determine the meaning of the term “substantially pure.”  In ‘610, Dr. D’Ambra stated that the term “substantially pure” meant pharmaceutical-grade, or 98%, purity.  Dr. D’Ambra statements were in relation to the piperidine derivative end product.  In light of the prosecution history of ‘610, the District Court held that a 98% purity requirement was applicable to the para-CPK intermediate.  Further, the District Court held that “substantially pure” meant 98% purity in relation to all chemical impurities of any kind present in the product, i.e. was not limited to regioisomeric impurity.

In view of the District Court’s claim construction, Appellants stipulated that infringement could not be proven.  Final judgment was entered for the Appellee, Appellants timely filed an appeal.

Law

There is a heavy presumption that claim terms are to be given their ordinary and customary meaning.  Phillips v. AWH Corp., 415 F.3d 1303, 1312-13 (Fed. Cir. 2005) (en banc).

Claims…must be construed in light of the appropriate context in which the claim term is used.  See Toro Co. v. White Consol. Indus., Inc., 199 F.3d 1295, 1299 (Fed. Cir. 1999).

The written description and other parts of the specification…may shed contextual light on the plain and ordinary meaning; however, they cannot be used to narrow a claim term to deviate from the plain and ordinary meaning unless the inventor acted as his own lexicographer or intentionally disclaimed or disavowed claim scope.  Id. at 1316.

The same claim term can have different constructions depending upon the context of how the term is used within the claims and the specification.  See Microprocessor Enhancement Corp. v. Tex. Instruments, Inc., 520 F.3d 1367, 1375 (Fed. Cir. 2008).  (while there is a presumption that a claim term will be construed consistently when used throughout the claims, there is no requirement that a claim term be construed uniformly, particularly if it would lead to a “nonsensical reading.”) See also Epcon Gas Systems, Inc. v. Bauer Compressors, Inc., 279 F.3d 1022 (Fed. Cir. 2002).

A court can look to the prosecution history of related patents for guidance in claim construction.  See Ormco Corp. v. Align Tech., Inc., 498 F.3d 1307, 1314 (Fed. Cir. 2007).

CAFC Decision

The CAFC held that the District Court erred in applying the “one construction throughout the patent” rule.

While “substantially pure” refers to both the CPK intermediate and the piperidine derivative end product in the specification, the term “substantially pure” is used only in reference to the CPK intermediate in relevant claims 1, 6 and 7.  And unlike other patents in the family, there is no explicit “substantially pure” limitation placed on the piperidine derivative end product in the relevant claims of the ‘703 patent.  The lack of any “substantially pure” limitation on the piperidine derivative end products in claims 1, 6 and 7 obviates any explicit requirement to apply a construction of “substantially pure” that is consistent for both the CPK intermediate and the piperidine derivative end product.

See page 22.  The CAFC noted that a skilled artisan would “recognize that an intermediate of the claimed chemical reaction would not be required to have the same purity as the end product.”  Id.  The CAFC asserts that the claim construction by the District Court fails to take into consideration the novel feature of ‘703, which is achieving a piperidine derivative end product of higher regioisomeric purity, thereby requiring less extensive purification.

Appellees argue that in Epcon and Microprocessor the intrinsic record clearly and expressly supported multiple interpretations of a single claim term.  The CAFC cites Phillips to hold that “that we must always construe the specification in light of the knowledge of one of ordinary skill in the art.”  Phillips, 415 F.3d 1313.  The CAFC holds that a skilled artisan would recognize that the purity of an intermediate compound in a reaction does not necessary have to be the same as the purity of an end product.

Further, the CAFC holds that the District Court erred in adopting the “one-size-fits-all” construction because it fails to take into consideration the next word, “regioisomer”.”  The CAFC notes that the full term “substantially pure regioisomer”, is used only in reference to the CPK intermediate.”

[B]y decoupling the modifier “substantially pure” from “regioisomer” for purposes of claim construction, the district court imposes a single interpretation even though that context requires separate definitions of “substantially pure” when applied to the CPK intermediate as opposed to the piperidine derivative end product.  We thus conclude that the district court erred in requiring that “substantially pure” have the same interpretation when applied to the CPK intermediate and the piperidine derivative end product.

See page 24.

Since the prosecution history of ‘610 focused on piperidine end product, the CAFC noted that it did not assist in construing the term “substantially pure regioisomer.”  There is no reason to apply the definition of “substantially pure” in relation to the piperidine end product in the prosecution history of ‘610 to the claimed term “substantially pure regioisomer” of the ‘703 patent.

The CAFC applied the “ordinary and customary” definition to the claim term since there is no explicit definition of the term “substantially pure” in the claims, specification or prosecution history.  In the past, the CAFC has interpreted “substantially” as a non-specific term of approximation that avoids a numerical boundary.  Appellants argued that the term “substantially pure regioisomer” should be construed as “largely but not wholly the para regioisomer of the intermediate of the structure shown, as compared to the meta isomer.”  The CAFC agreed and held that “ ‘[l]argely but not wholly’ is consistent with a flexible approach to regioisomeric purity for an intermediate, is faithful to the specification’s silence regarding numerical precision, and, most importantly, is not arbitrarily tied to the FDA standard for pharmaceutical-grade end products.”  See page 28.

Dissent

The Dissent agreed with the District Court and noted that there was no evidence to support that the inventor intended the term to have more than one meaning.  The Dissent agrees with Appellee’s argument, the intrinsic evidence must provide a distinction between the way “substantially pure” is interpreted with respect to a CPK-intermediate verses a piperidine derivative end product.

Takeaway

The Drafter of a specification is encouraged to take advantage of the opportunity to be their own lexicographer.  Providing explicit definitions in the specification is a time efficient and cost efficient way to ensure proper claim instruction.

Present dependent claims reciting numerical ranges of various features, i.e. recite a numerical value for purity.

If there is a lack of intrinsic evidence in a patent, the court may look to the prosecution history of related applications to achieve claim construction.

Patent

CAFC Decision

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