DCT
1:01-cv-01867
Abbott Lab v. Baxter Phar Prod Inc
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Abbott Laboratories (Illinois) and Central Glass Company Ltd. (Japan)
- Defendant: Baxter Pharmaceutical Products, Inc. (Delaware) and Baxter Healthcare, Corp. (Delaware)
- Plaintiff’s Counsel: Winston & Strawn
- Case Identification: 1:01-cv-01867, N.D. Ill., 03/16/2001
- Venue Allegations: Venue is alleged to be proper as Defendants conduct and transact business within the judicial district.
- Core Dispute: Plaintiffs allege that Defendant’s filing of an Abbreviated New Drug Application (ANDA) for a generic sevoflurane product constitutes an act of infringement of a patent related to stabilizing the anesthetic composition.
- Technical Context: The technology concerns pharmaceutical chemistry, specifically methods for preventing the chemical degradation of the inhalant anesthetic sevoflurane when stored.
- Key Procedural History: The action arises under the Hatch-Waxman Act. The complaint was filed in response to a notice letter from Baxter, advising that it had filed an ANDA with a Paragraph IV certification. This certification alleges that Plaintiffs' patent is invalid and/or not infringed by Baxter's proposed generic product.
Case Timeline
| Date | Event |
|---|---|
| 1995-01-01 | Abbott receives FDA authorization to market sevoflurane |
| 1995-06-01 | Abbott begins selling sevoflurane in the U.S. |
| 1996-01-01 | Plaintiffs learn of sevoflurane degradation |
| 1997-01-27 | ’176 Patent Priority Date (Application Filing) |
| 1999-11-23 | ’176 Patent Issue Date |
| 2001-01-31 | Baxter sends ANDA Paragraph IV notice letter to Plaintiffs |
| 2001-03-16 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
- Patent Identification: U.S. Patent No. 5,990,176, “Fluoroether Compositions and Methods For Inhibiting Their Degradation In the Presence of a Lewis Acid,” issued November 23, 1999.
The Invention Explained
- Problem Addressed: The patent describes that certain fluoroether anesthetics, particularly sevoflurane, are unstable and can degrade when they come into contact with Lewis acids. These acids can be present as natural components (e.g., aluminum oxides) in glass containers, and their interaction with sevoflurane can produce potentially toxic byproducts, including hydrofluoric acid (Compl. ¶10; ’176 Patent, col. 1:50-64).
- The Patented Solution: The invention claims to solve this stability problem by adding an "effective stabilizing amount of a Lewis acid inhibitor" to the sevoflurane composition. The patent identifies water as the preferred inhibitor ('176 Patent, Abstract, col. 2:51-55). The inhibitor works by donating electrons to the Lewis acid, forming a bond that prevents the acid from reacting with and degrading the sevoflurane ('176 Patent, col. 4:61-68).
- Technical Importance: This stabilization method allows the anesthetic to be stored for longer periods without significant chemical degradation, which is a matter of "great concern to the medical community" due to the potential toxicity of the degradation products ('176 Patent, col. 1:56-64).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶15).
- The essential elements of independent claim 1 are:
- An anesthetic composition comprising:
- a quantity of sevoflurane; and
- a Lewis acid inhibitor in an amount effective to prevent degradation by a Lewis acid of said quantity of sevoflurane, said Lewis acid inhibitor selected from the group consisting of water, butylated hydroxytoluene, methylparaben, propylparaben, propofol, and thymol.
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
- The accused instrumentality is Baxter's proposed generic sevoflurane product, which is the subject of its ANDA filing (Compl. ¶13).
Functionality and Market Context
- The complaint alleges that Baxter's product is a sevoflurane formulation intended for commercial manufacture, use, and sale as a generic alternative to Abbott's branded Ultane® product (Compl. ¶1, ¶13). The infringement allegation is based on Baxter’s purported representations that its product, to be supplied in a non-glass container, "will have a measurable limited and controlled amount of water to effectively offset the unexpected presence of Lewis Acid" (Compl. ¶15).
IV. Analysis of Infringement Allegations
'176 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a quantity of sevoflurane | The accused product is a sevoflurane formulation, as identified in Baxter's ANDA submission. | ¶13 | col. 17:11 |
| a Lewis acid inhibitor ... selected from the group consisting of water... | The complaint alleges, based on Baxter’s representations, that the accused product will contain a "measurable limited and controlled amount of water." Water is a specifically enumerated Lewis acid inhibitor in the claim. The patent's specification includes experimental data, such as a bar graph showing that adding 400 ppm of water significantly inhibits the formation of degradants, to demonstrate the efficacy of the claimed invention (Compl. ¶11, Ex. A, Fig. 4). | ¶15 | col. 17:13-18 |
| in an amount effective to prevent degradation by a Lewis acid of said quantity of sevoflurane | The complaint alleges that the water in Baxter’s product is added "to effectively offset the unexpected presence of Lewis Acid." | ¶15 | col. 17:13-15 |
- Identified Points of Contention:
- Scope Questions: The central dispute may turn on the scope of the phrase "an amount effective to prevent degradation." A question for the court will be whether this phrase requires complete prevention of degradation, or if a significant reduction is sufficient. The patent’s specification, which uses terms like "inhibit" and provides experimental data showing reduction rather than total elimination, may support an interpretation that a reduction in degradation is sufficient ('176 Patent, col. 8:15-20).
- Technical Questions: A primary factual question will be what Baxter’s ANDA submission actually discloses about the amount of water in its proposed product and its stabilizing effect. The complaint's allegation is based on "representations" from a notice letter, but the technical data within the ANDA itself will be the key evidence for determining whether the accused product meets the claim limitations (Compl. ¶15).
V. Key Claim Terms for Construction
- The Term: "an amount effective to prevent degradation"
- Context and Importance: This functional language is the core of the invention and the infringement dispute. The definition will determine the threshold of stabilization required to infringe. Practitioners may focus on this term because Baxter's defense will likely argue that any water in its product is incidental or not present in a quantity that meets the claimed "effective" level.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent repeatedly uses the term "inhibit" in its summary and detailed description, suggesting that a reduction or slowing of degradation, rather than complete stoppage, could fall within the claim scope ('176 Patent, col. 2:9, col. 8:15-20). The specification's examples demonstrate varying levels of degradation reduction, not absolute prevention, which could support a construction that does not require zero degradation ('176 Patent, Tables 2-7).
- Evidence for a Narrower Interpretation: Dependent claim 3, which claims "[t]he composition of claim 2 containing at least about 0.04% w/w to about 0.14% w/w of water," provides specific quantitative ranges that a party could argue inform the meaning of an "effective" amount ('176 Patent, col. 17:31-32). A defendant might argue that to be "effective," the amount must achieve the high levels of inhibition demonstrated in specific patent examples under specific conditions.
VI. Other Allegations
- Indirect Infringement: The complaint does not plead induced or contributory infringement. The action is based on the statutory act of infringement under 35 U.S.C. § 271(e)(2)(A), which arises from the filing of an ANDA seeking approval to market a drug claimed in a patent before its expiration (Compl. ¶16).
- Willful Infringement: While the complaint does not contain a separate count for willful infringement, it does request that the case be declared "exceptional" and seeks attorneys' fees pursuant to 35 U.S.C. § 285 (Compl. p. 4, ¶B). The basis for this appears to be Baxter's alleged knowledge of the patent, evidenced by its Paragraph IV certification and notice letter sent to Abbott (Compl. ¶13-14).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope and fact: Does the quantity of water in Baxter's proposed generic sevoflurane, as described in its ANDA, constitute "an amount effective to prevent degradation"? This requires first construing the claim term and then comparing the technical evidence from the ANDA against that construction.
- A key evidentiary question will be the content of Baxter’s ANDA filing. The complaint's allegations are based on representations in a notice letter; the case will ultimately depend on whether the detailed chemical and stability data in the confidential ANDA submission shows a composition that falls within the scope of the asserted claims.