DCT

3:17-cv-06832

Bristol Myers Squibb Co v. Emcure Pharma Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:17-cv-06832, D.N.J., 09/06/2017
  • Venue Allegations: Venue is alleged to be proper based on an e-mail from Defendants' counsel dated August 21, 2017, in which Defendants agreed not to contest jurisdiction or venue in the District of New Jersey.
  • Core Dispute: Plaintiff alleges that Defendants' Abbreviated New Drug Applications (ANDAs) for generic versions of the HIV drug Reyataz® (atazanavir sulfate) constitute an act of infringement of a patent covering a specific salt form of the active ingredient.
  • Technical Context: The technology concerns a specific salt formulation of an azapeptide HIV protease inhibitor, designed to improve the drug's solubility and bioavailability for oral administration.
  • Key Procedural History: This action was initiated under the Hatch-Waxman Act following Defendants' notification to Plaintiff of their filing of two ANDAs with Paragraph IV certifications. The complaint notes that a related case, Bristol-Myers Squibb Co. v. Zydus Pharms. (USA) Inc., Civil Action No. 17-5337, involves the same patent and drug product.

Case Timeline

Date Event
1998-01-20 ’383 Patent Priority Date
2000-07-11 ’383 Patent Issue Date
2017-08-11 Defendants sent Reyataz® Notice Letters to Plaintiff
2017-08-14 Plaintiff received Reyataz® Notice Letters
2017-08-21 Defendants agreed not to contest venue
2017-09-06 Complaint Filing Date
2018-12-21 ’383 Patent Expiration Date
2019-06-21 Pediatric Exclusivity Expiration Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 6,087,383 - "Bisulfate Salt of HIV Protease Inhibitor" (issued Jul. 11, 2000)

The Invention Explained

  • Problem Addressed: The patent addresses the challenge that the free base form of a promising azapeptide HIV protease inhibitor (referred to as "compound I") has "extremely low solubility" in aqueous vehicles and consequently "poor oral bioavailability," limiting its usefulness as an oral drug (’383 Patent, col. 1:40-43).
  • The Patented Solution: The invention is a specific crystalline bisulfate salt of compound I. This particular salt form is described as having "unexpectedly superior aqueous solubility/dissolution behavior" and "significantly improved oral bioavailability" compared not only to the free base but also to other common acid addition salts like hydrochloride and sulfate (’383 Patent, col. 1:29-32, col. 2:53-57). The patent's Figure 1 graphically depicts the pH-solubility profile, illustrating the solubility behavior that underlies the invention's purported advantages (’383 Patent, Fig. 1).
  • Technical Importance: Developing an orally bioavailable form of a protease inhibitor was critical for creating effective, patient-compliant HIV treatment regimens (’383 Patent, col. 1:44-46).

Key Claims at a Glance

  • The complaint asserts independent claim 1 and dependent claim 2 (’383 Patent, col. 6:30-42; Compl. ¶¶ 21, 26).
  • Independent Claim 1:
    • The bisulfate salt
    • having the specific chemical structure designated as formula II
  • The complaint does not explicitly reserve the right to assert other claims.

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are the generic drug products containing atazanavir sulfate described in Defendants’ ANDA Nos. 078785 (for 100 mg, 150 mg, and 200 mg capsules) and 200196 (for 300 mg capsules) (the "Emcure ANDA Products") (Compl. ¶¶ 1-2).

Functionality and Market Context

The complaint alleges that the Emcure ANDA Products contain "atazanavir bisulfate" (Compl. ¶16). By filing the ANDAs, Defendants have represented to the FDA that their proposed generic products have the same active ingredient, dosage form, and strengths as Plaintiff's branded Reyataz® product and are bioequivalent to it (Compl. ¶15). The filing of the ANDAs is a technical act of infringement intended to secure FDA approval to market a generic version of Reyataz® before the expiration of the ’383 patent (Compl. ¶¶ 14, 21).

IV. Analysis of Infringement Allegations

The complaint provides a conclusory theory of infringement typical in ANDA litigation, without attaching claim charts or detailed technical analysis. The core allegation is that the product described in the ANDAs, if commercially manufactured and sold, would literally infringe the asserted claims.

’383 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
The bisulfate salt having the formula [II] The complaint alleges that the Emcure ANDA Products "contain atazanavir bisulfate" and that the product described in the ANDAs would infringe claim 1. This implies the atazanavir bisulfate in the accused products is the same chemical compound as that depicted in formula II. ¶16, ¶21, ¶26 col. 6:31-40
  • Identified Points of Contention:
    • Chemical Identity: The central question is whether the active pharmaceutical ingredient (API) specified in Defendants' ANDAs is structurally and compositionally identical to the bisulfate salt defined by formula II in claim 1. The complaint does not provide the ANDA specification or any analytical data to substantiate this allegation.
    • Scope Questions: The patent distinguishes the claimed "bisulfate salt" from a "sulfate salt" which it describes as a hydrated "2:1 salt" (’383 Patent, col. 3:42-45). This raises the question of whether the claim term "bisulfate salt" requires a specific 1:1 stoichiometric ratio of the azapeptide base to sulfuric acid, and whether the accused product meets this limitation.
    • Technical Questions: The patent describes different crystalline forms ("Type-I" and "Type-II") (’383 Patent, col. 6:1-5). While claim 1 is not expressly limited to a specific polymorph, a dispute could arise as to whether the claim scope implicitly covers only certain forms, and whether the accused product utilizes a different, potentially non-infringing, crystalline structure.

V. Key Claim Terms for Construction

  • The Term: "bisulfate salt"
  • Context and Importance: This term defines the chemical composition of the invention. Its construction is critical because infringement hinges on whether the accused product is this specific salt. Practitioners may focus on this term because the patent's specification draws a distinction between the claimed "bisulfate salt" and a different "sulfate salt," suggesting the term may carry a specific technical meaning beyond its general chemical definition (’383 Patent, col. 3:42-45).
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: A party could argue the term should be given its plain and ordinary meaning in chemistry, referring to any salt formed with the bisulfate (HSO₄⁻) anion, without limitation to a specific crystalline form unless otherwise specified.
    • Evidence for a Narrower Interpretation: The specification contrasts the invention with other salts that convert back to the poorly soluble free base in water. It states, "the extra proton of the bisulfate salt prevents the conversion to the free base" (’383 Patent, col. 2:62-63). This functional language, along with the explicit differentiation from the 2:1 "sulfate salt," could support an argument that "bisulfate salt" is limited to a 1:1 stoichiometric compound that exhibits this specific stabilizing property.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that upon FDA approval, Defendants' commercial activities would induce and/or contribute to infringement by others under 35 U.S.C. §§ 271(b) and (c) (Compl. ¶¶ 22, 27). The factual basis for these future-looking allegations is the act of filing the ANDAs to seek approval for a product that is allegedly a copy of the patented drug.
  • Willful Infringement: The complaint does not contain an explicit allegation of willful infringement. It states that Defendants provided a Paragraph IV certification asserting the ’383 patent is invalid, unenforceable, and/or not infringed, which establishes knowledge of the patent as of the notice letters (Compl. ¶18).

VII. Analyst’s Conclusion: Key Questions for the Case

  1. A central issue will be one of chemical identity: does the active pharmaceutical ingredient described in Defendants' confidential ANDA submissions meet the precise structural and compositional requirements of the "bisulfate salt" as defined by formula II in Claim 1 of the ’383 patent? The resolution of this question will likely depend on expert analysis of the ANDA data during discovery.
  2. A key legal question will be one of claim scope: can the term "bisulfate salt" be narrowly construed to require a specific 1:1 stoichiometric ratio and potentially a specific crystalline form, based on the patent's explicit differentiation from a "sulfate salt" and its emphasis on the functional role of the "extra proton"? The outcome of this construction could determine whether Defendants' product, if it differs slightly in form or composition, falls outside the scope of the claim.