In Re Gabapentin Patent Litigation

395 F. Supp. 2d 140, 2005 WL 2651274
CourtDistrict Court, D. New Jersey
DecidedAugust 25, 2005
DocketMDL NO. 13874(JCL), 00-2931(JCL), CIV.A.00-4168(JCL), CIV.A.00-4589(JCL)
StatusPublished
Cited by2 cases

This text of 395 F. Supp. 2d 140 (In Re Gabapentin Patent Litigation) is published on Counsel Stack Legal Research, covering District Court, D. New Jersey primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
In Re Gabapentin Patent Litigation, 395 F. Supp. 2d 140, 2005 WL 2651274 (D.N.J. 2005).

Opinion

395 F.Supp.2d 140 (2005)

In re GABAPENTIN PATENT LITIGATION
Pfizer Inc., Warner-Lambert Co., and Godecke Aktiengesellschaft, Plaintiffs,
v.
Teva Pharmaceuticals USA, Inc. and Teva Pharmaceuticals Industries, Ltd., Defendants.

Nos. MDL NO. 13874(JCL), 00-2931(JCL), CIV.A.00-4168(JCL), CIV.A.00-4589(JCL).

United States District Court, D. New Jersey.

August 25, 2005.

*141 John J. Francis, Jr., Drinker Biddle & Reath, Florham Park, NJ, David S. Copeland, Leora Ben-Ami, Stephen J. Elliott, Kaye Scholer, LLP, New York City, for Plaintiffs.

Allyn Zissel Lite, Lite, Depalma, Greenberg and Rivas, LCC, Arnold B. Calmann, Saiber, Schlesinger, Satz & Goldstein, LLC, Newark, NJ, Patrick J. Hughes, Connell Foley, LLP, Roseland, NJ, Neil S. Cartusciello, Mendham, NJ, for Defendants.

MEMORANDUM AND ORDER

LIFLAND, District Judge.

Plaintiffs Pfizer, Inc., Warner-Lambert Co., and Godecke Aktiengesellschaft (collectively, "Warner-Lambert") brought suit against Defendants Teva Pharmaceuticals USA, Inc. and Teva Pharmaceutical Industries, Ltd. (collectively, "Teva"), alleging infringement of U.S. Patent No. 6,054,482, entitled "Lactam-Free Amino Acids" ("'482 patent").[1] Before the Court is the *142 Motion of Teva for summary judgment of noninfringement of claims 7-11 of the '482 patent based on use of certain adjuvants. For the reasons set forth herein, Teva's Motion will be denied.

BACKGROUND

Neurontin® is sold by Warner-Lambert as an aid in the treatment of epileptic seizures and other cerebral disorders. The active ingredient in Neurontin® is a chemical compound called gabapentin, discovered by Warner-Lambert in the mid 1970s. Early research demonstrated that gabapentin had a propensity to undergo a chemical reaction resulting in an impurity known as gabapentin lactam, which was more than twenty-five times as toxic as gabapentin. Lactam caused rather than prevented seizures.[2] Subsequent research revealed that both the purity of the starting gabapentin and the "catalytic effects" of certain ingredients, or adjuvants, mixed therewith contributed to the production of lactam. The development of a stable gabapentin formulation became the focus of first a German, and then a United States patent application that ultimately issued to Warner-Lambert on April 25, 2000 as the '482 patent. The '482 patent expires on April 25, 2017.

A. The '482 Patent

The '482 patent includes eleven claims. Claims 1 through 6 of the '482 patent are process claims. (Col. 6, l. 55 to Col. 8, l. 28). Claim 7 of the '482 patent, the only independent product claim, states:

7. A stable and pure pharmaceutical composition in unit dry medicinal dosage form consisting essentially of:

(i) an active ingredient which is gabapentin in the free amino acid, crystalline anhydrous form containing less than 0.5% by weight of its corresponding lactam and less than 20 ppm of an anion of a mineral acid and

(ii) one or more pharmaceutically acceptable adjuvants that do not promote conversion of more than 0.2% by weight of the gabapentin to its corresponding lactam form when stored at 25 C and an atmospheric humidity of 50% for one year.

(Col. 8, ll. 29-40 (emphasis added)). Claims 8-11 depend from claim 7 and, therefore, incorporate all the limitations of claim 7. Claim 8 limits the selection of "pharmaceutically acceptable" adjuvants. (Col. 8, ll.41-49). Claims 9 and 10 limit the dry medicinal dosage forms to a tablet and capsule, respectively. (Col. 8, ll.50-53). Claim 11 limits the mineral acid in claim 7(i) to hydrochloric acid. (Col. 8, ll.54-55).

The written description of the '482 patent explains research efforts concerning the role of certain adjuvants in the gabapentin lactam conversion process. Lactam formation in gabapentin formulations was caused in part by "catalytic effects" of the ingredients-the adjuvants-that are combined with gabapentin to make a formulation. (Col. 4, ll.58-62). For example, where Poloxamer NF was the "sole" adjuvant, it did not impair the stability of the active material gabapentin. (Col. 4, ll.64-67). The specification also indicates that an adjuvant can be acceptable under one condition but not acceptable under a different condition. In one test using polyethylene glycol (PEG) as an adjuvant, *143 "cyclization to the lactam took place to a considerable extent"; whereas when used with "very pure active substance," i.e., very pure gabapentin, "PEG was found to be indeed usable as an excipient." (Col. 5, ll.1-14). The specification goes on to explain that

[i]n order to establish which adjuvant materials promote the lactam formation, laborious serial investigation had, therefore, to be carried out....

The following adjuvant materials, for example, reduced the stability of the compounds (I) and should be avoided in the preparation of pharmaceutical compositions: modified maize starch, sodium croscarmelose, glycerol behenic acid ester, methacrylic acid co-polymers (types A and C), anion exchangers, titanium dioxide, and silica gels such as Aerosil 200.

(Col. 4, l. 62 — Col. 5, l. 10 (emphasis added)). It also identifies thirteen adjuvants found to have "no noticeable influence" on the stability of gabapentin. (Col. 5, ll.11-17).

The patent then summarizes the conditions that should be maintained to achieve a pure and stable pharmaceutical composition:

[i]n order not to exceed the upper limit of 0.5% by weight of gabapentin lactam (referred to the gabapentin), which is regarded as being permissible, and in order to ensure the storage stability not only of the active material but also of the corresponding pharmaceutical forms of preparation, the following procedures are to be maintained:

1. The active materials of formula (I) must be prepared as highly purified, nonderivatized free amino acids, for example, from the corresponding hydrochloride by ion exchange. The proportion of remaining hydrochloride admixtures should thereby not exceed 20 ppm. The same also applies to other mineral acids.

2. In the case of pharmaceutical preparations or compositions, by the precise choice of adjuvant materials, every catalysis of the lactam formation must be suppressed.

3. By controls, it must be ensured that the above conditions are fulfilled. As a rule, this is the case when the lactam formation, under the storage conditions generally applicable for medicaments, does not increase within a period of time of 1 year after production of the pharmaceutical compositions or of the active material by more than 0.2% by weight and preferably 0.1% by weight, referred to the pure active material.

(Col. 5, ll. 18-41 (emphasis added)).

B. The '482 Patent Prosecution History

The grant of the '482 Patent came after a series of continuation United States patent applications and multiple reviews by the patent examiner. Warner-Lambert filed its initial patent application on August 21, 1990. Claim 5 of the application stated: "A pharmaceutical composition which comprises a therapeutically effective amount of a compound according to claim 1 in combination with a pharmaceutically acceptable carrier [i.e., adjuvant]." (Rakoczy Decl., Ex. B at 00033).[3] An April *144 1991 Office Action rejected all the claims (1-6) as being anticipated under 35 U.S.C. § 102(b) and, alternatively, as obvious under 35 U.S.C.

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Related

In Re Gabapentin Patent Litigation
503 F.3d 1254 (Federal Circuit, 2007)
Warner-Lambert Co. v. Purepac Pharmaceutical Co.
503 F.3d 1254 (Federal Circuit, 2007)

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