Eisai Co., Ltd. v. Dr. Reddy's Laboratories, Ltd.

• Decision Date: 06 October 2006
• Docket Number: No. 03 Civ. 9053(GEL).,No. 03 Civ. 9223(GEL).,03 Civ. 9053(GEL).,03 Civ. 9223(GEL).
• Citation: 472 F.Supp.2d 493
• Parties: EISAI CO., LTD. and Eisai Inc., Plaintiffs, v. DR. REDDY'S LABORATORIES, LTD., Dr. Reddy's Laboratories, Inc., Defendants. Eisai Co., Ltd. and Eisai Inc., Plaintiffs, v. Teva Pharmaceuticals USA, Inc., Defendant.
• Court: U.S. District Court — Southern District of New York

472 F.Supp.2d 493

EISAI CO., LTD. and Eisai Inc., Plaintiffs, v. DR. REDDY'S LABORATORIES, LTD., Dr. Reddy's Laboratories, Inc., Defendants.

Eisai Co., Ltd. and Eisai Inc., Plaintiffs, v. Teva Pharmaceuticals USA, Inc., Defendant.

No. 03 Civ. 9053(GEL).

No. 03 Civ. 9223(GEL).

United States District Court, S.D. New York.

October 6, 2006.

Robert L. Baechtold, Joseph M. O'Malley, Bruce M. Wexler, Fitzpatrick, Cella, Harper & Scinto, New York, NY; David B. Tulchin, James T. Williams, and Bradley A. Harsch, Sullivan & Cromwell LLP, New York, NY, for Plaintiffs.

Maurice B. Ross, Louis H. Weinstein, Ellen T. Lowenthal, Nathaniel I. Watts, Budd Larner, P.C., Short Hills, NJ, for Defendants Dr. Reddy's Laboratories, Ltd. and Dr. Reddy's Laboratories Inc. David M. Hashmall, Frederick H. Rein, and Elaine Herrmann Blais, Goodwin Proctor LLP, New York, NY, for Defendant Teva Pharmaceuticals USA, Inc.

OPINION AND ORDER

LYNCH, District Judge.

The Hatch-Waxman Act, 21 U.S.C. § 355 and 35 U.S.C. § 271(e) (1994) (codified as amended), permits would-be manufacturers of generic versions of an already approved, patented drug to seek expedited approval from the Food and Drug Administration ("FDA") before expiration of the patent, by means of an Abbreviated New Drug Application ("ANDA"). See Yamanouchi Pharmaceutical Co., Ltd. v. Danbury Pharmacal, Inc., 231 F.3d 1339, 1342 (Fed.Cir.2000). Filing an ANDA constitutes an "artificial" but legally cognizable instance of patent infringement, often triggering a lawsuit in which the validity and enforceability of the patent may be tested. Glaxo Group Ltd. v. Apotex, Inc., 376 F.3d 1339, 1344 (Fed.Cir.2004).

Dr. Reddy's Laboratories, Ltd., and Dr. Reddy's Laboratories, Inc. (collectively, "Reddy"), and Teva Pharmaceuticals USA, Inc. ("Teva"), the defendants in these actions, each filed an ANDA, seeking to manufacture generic versions of a gastricacid inhibitor that is marketed under the brand name Aciphex. Plaintiffs Eisai Co., Ltd. and Eisai Inc. (collectively, "Eisai"), hold the patent on rabeprazole sodium, the active ingredient of Aciphex. Eisai duly brought these actions for patent infringement against defendants.¹ Defendants argue that Eisai's patent should not be enforced because Eisai engaged in inequitable conduct before the U.S. Patent and Trademark Office ("PTO") during prosecution of its patent application. Eisai now moves for summary judgment on all defendants' allegations of inequitable conduct. For the reasons below, the motion is granted in part, but for the most part denied.²

THE PATENT PROSECUTIONS

To address the parties' contentions requires reciting in some detail the history of the prosecutions of both the rabeprazole patent and another Eisai patent application that defendants argue is closely related. The following facts regarding those prosecutions are undisputed except as otherwise noted. Given the scope and somewhat specialized nature of the record, however, citations are provided to identify the source of certain facts. Where citations point to a statement in a party's brief or other non-evidentiary submission, that statement is generally uncontested and usually itself points to evidentiary material in the record.

I. Prosecution of The Patent-in-Suit

Eisai, a pharmaceutical company, owns U.S. Patent No. 5,045,552 ("`552 patent"), the patent-in-suit. The '552 patent claims, among other things, the chemical compound rabeprazole and its salts.³ Rabeprazole sodium is the active ingredient in a drug that Eisai developed and made commercially available under the brand name Aciphex. The drug was approved by the FDA in 1991 for treatment of certain gastric ailments including duodenal ulcers and heartburn. Rabeprazole functions as a "proton pump inhibitor," because it suppresses gastric-acid production by inhibiting the action of an enzyme, H+K+ATPase, which pumps into the stomach protons (H+ ions) that combine with chloride ions to form hydrochloric (gastric) acid. (Ds. Joint R. 56.1 Stmt. ¶ 15.) The market for Aciphex is a lucrative one: Eisai's worldwide sales of the drug have been reported at over $1 billion per year. (Ds. Joint R. 56.1 Stmt. ¶¶ 1-5.)

On November 10, 1987, Eisai's attorney Arthur R. Crawford filed the application that resulted in the '552 patent.⁴ ('552 File History, DRLRAB 51.)⁵ The application reported that the compound now referred to as rabeprazole⁶ belonged to a known class whose chemical structures include a benzimidazole ring on the left side of the molecule as diagramed in the standard chemical notation, and a pyridine ring on the right, joined by a sulfinylmethyl group. (P.Ex. 1, '552 patent, col. 1, lines 40-44.) Numerous compounds feature this basic chemical structure, including prominently omeprazole, the first commercially available proton pump inhibitor; omeprazole was disclosed in a group of patents (known as "Junggren" after an inventor) owned by the Swedish company now known as AstraZeneca AB. It is the active ingredient in the drug marketed as Prilosec.⁷ (Ds. Joint R. 56.1 Stmt ¶ 19; '552 Patent File History, DRLRAB 54, 431; see also Teva Mem. in Opp. to P. Mot. for Summ. J. of Patent Validity, 1-2.) The compounds are formally distinguishable primarily by the particular "substitutions" of chemical groups for hydrogen atoms around their pyridine rings. The structure of rabeprazole's pyridine ring reflects a pattern of substitution referred to in this litigation as "asymmetrical," because its 3-position is substituted (with a methyl group) while the 5-position is unsubstituted (that is, it is bonded to a hydrogen atom); the 4-position is substituted with a methoxypropoxy group (OCH2 CH2CH2OCH3), a type of alkoxy group.⁸ (P. Mem., glossary at 7.) Other related compounds, some of which are potentially useful in the inhibition of gastric-acid formation, have different patterns of pyridine-ring substitution, including the use of different alkoxy groups at the 4-position. The benzimidazole ring of rabeprazole is unsubstituted. (Id.)

Eisai reported having synthesized rabeprazole by working from omeprazole. (P.R. 56.1 Stmt. ¶¶ 18, 24.) Eisai disclosed summaries of three sets of pharmacological data comparing, relevantly, omeprazole to rabeprazole. (Ds. Joint R. 56.1 Stmt. ¶ 37.) These disclosures will be further discussed in relation to defendants' inequitable conduct claims, but, in brief, they purported to demonstrate rabeprazole's superior potency and its enabling of faster post-dosage recovery of acid secretion as compared to omeprazole.⁹ (P.R. 56.1 Stmt. ¶¶ 19, 21, 23-27, 36-39 (citing '552 patent)). The submitted data were not the only existing pharmacological comparisons involving rabeprazole, as will further be discussed in relation to the inequitable conduct claims.

A. First Rejection and Eisai's Response

Patent examiner Jane Fan rejected the rabeprazole claims three times, prompting various persuasive efforts by Eisai, before ultimately allowing the claims to issue as the '552 patent. On September 21, 1988, Fan rejected the claims as obvious in light of certain prior art: the Junggren patents and Great Britain Patent No. 2,234,523 ("GB '523"). (Ds. Joint R. 56.1 Stmt. ¶¶ 41-42.) "[Junggren] and [GB '523] generically teach[] R4 [the 4-position on the pyridine ring] being methoxyethoxy or ethoxyethoxy," wrote Fan.¹⁰ ('552 File History at DRLRAB 292.) Fan specifically cited and diagramed a prior art-compound, Example 27 of Junggren, which bears a methoxyethoxy substituent at the 4-position of its pyridine ring. ('552 File History, DRLRAB 292-93.) Fan concluded that the "[prior] art compounds are homologs of the claimed compounds rendering the claimed compounds unpatentable." (Id. at 293.) The rejection of the rabeprazole claims was not based on lack of novelty. (Ds. Joint R. 56.1 Stmt. ¶ 42.)

Eisai reacted to this first rejection in various ways. On March 21, 1989, Eisai attorney Crawford offered a response that addressed both the structural and functional distinctiveness of rabeprazole. With respect to chemical structure, the response distinguished rabeprazole's 4-position substituent, methoxypropoxy, from those of compounds in the prior art. Eisai submitted that Junggren and GB '523 disclosed only compounds bearing a methoxyethoxy group at the 4-position of the pyridine ring and "thus novelty is established" — presumably, although not explicitly, contrasting rabeprazole's methoxypropoxy substituent. ('552 Patent File History, DRLRAB 429.) Further, Eisai pointed out that the "[s]pecific compounds disclosed in [GB '523] and [Junggren] are substituted at both the Sand 5-position by methyl groups, as in the GB ['523] patent, or unsubstituted in both the 3- and 5-positions." (Id. at DRLRAB 429, emphasis in original.) The response continued, "Applicants' claims allow for the possibility of unsubstitution or a lower alkyl at the 3-position with no substitution at the 5-position; preferably, the 3-position ... is methyl" — describing the asymmetrical pyridine-ring substitution pattern that is found in rabeprazole. (Id.)

In addition to discussing structural traits, Eisai's March 21 response also addressed the pharmacological properties of the claimed compounds. Eisai professed that compounds "in which the substituent at the 4-position is propoxymethoxy"¹¹ exhibited "unexpected anti-ulcer activity." ('552 Patent File History, DRLRAB 429.) It also submitted additional pharmacological comparisons with omeprazole, alleging omeprazole's overall inferiority with respect to acid-inhibition and post-dosage recovery. (Id. at DRLRAB 541.)¹² The response sought to justify Eisai's choice of omeprazole as a comparator:

As ... the [prior] art shows a preference for a specific compound currently under development and known as Omeprazole, ... applicants have compared their elected compound with Omeoprazole [sic ] and not compounds more nearly structurally related to the claimed compounds.... This is appropriate in accordance with In re...