PTAB

IPR2013-00253

Ikaria Inc v. Geno LLC

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1. Case Identification

2. Patent Overview

  • Title: CONVERSION OF NITROGEN DIOXIDE (NO₂) TO NITRIC OXIDE (NO)
  • Brief Description: The ’997 patent discloses an apparatus for converting nitrogen dioxide (NO₂) to nitric oxide (NO). The apparatus comprises a receptacle, such as a cartridge, containing an antioxidant coated on a surface-active material that reacts with a gas flow containing NO₂.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-6 under 35 U.S.C. §102 over Schleicher

  • Prior Art Relied Upon: Schleicher (Patent 5,846,297).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Schleicher discloses every element of claims 1-6. Schleicher teaches a filter cartridge (a "receptacle") with an inlet and outlet for converting NO₂ to NO in medical gas delivery. The cartridge contains polyarylene ether, which Petitioner asserted acts as a reducing agent (the "antioxidant") that reacts with NO₂ to produce NO. Schleicher also discloses that this reducing agent can be coated on support materials like silica gel, which the ’997 patent identifies as a "surface-active material" capable of retaining water, thus meeting the limitations of the dependent claims.

Ground 2: Obviousness of Claim 7 under 35 U.S.C. §103 over Schleicher in view of Seitz, Kanda, and Mergens

  • Prior Art Relied Upon: Schleicher (Patent 5,846,297), Seitz (Patent 6,103,275), Kanda (a 1990 journal article), and Mergens (Patent 3,958,580).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claim 7, which specifies the antioxidant is ascorbic acid, alpha tocopherol, or gamma tocopherol. Petitioner argued that substituting the polyarylene ether of Schleicher with ascorbic acid would have been obvious. Seitz and Kanda taught that ascorbic acid was a preferred, biocompatible reducing agent for quantitatively converting nitrite (NO₂⁻), a closely related chemical species, to NO. Mergens further disclosed that a mixture of ascorbic acid and sodium ascorbate reacts directly with NO₂ to produce NO.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine these teachings because ascorbic acid was well-known as a safe, inexpensive, and effective reducing agent for generating NO from nitrogen oxides. These properties would have motivated a POSITA to select ascorbic acid over other agents for use in Schleicher’s therapeutic gas conversion cartridge.
    • Expectation of Success: The prior art demonstrated that ascorbic acid quantitatively converted related nitrogen oxides to NO. Mergens specifically taught the direct reaction between ascorbic acid and NO₂. This created a strong and reasonable expectation that substituting ascorbic acid into the Schleicher apparatus would successfully and predictably convert NO₂ to NO.

Ground 3: Obviousness of Claims 8-12, 14-19, and 21 under 35 U.S.C. §103 over Schleicher in view of Chand

  • Prior Art Relied Upon: Schleicher (Patent 5,846,297) and Chand (Patent 4,399,942).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground addressed independent claim 8, which recites an apparatus for generating therapeutic gas that includes a "permeation cell" for diffusing gaseous NO₂ into a gas flow, combined with the NO₂-to-NO conversion receptacle of claim 1. Petitioner asserted that Chand explicitly discloses a permeation device for emitting a gas, such as liquid NO₂, at a constant rate into a moving fluid. This device meets every limitation of the claimed permeation cell. Schleicher provides the second component: the NO₂-to-NO conversion cartridge.
    • Motivation to Combine: A POSITA would combine Chand's permeation cell with Schleicher's conversion cartridge to yield a predictable result. The combination creates a portable, patient-friendly system for generating therapeutic NO from a liquid NO₂ source. This was argued to be a significant advantage over using heavy, high-pressure gas cylinders, providing a clear motivation to combine the known elements.
    • Expectation of Success: The combination involved joining two existing devices, each performing its known function. Chand’s device would produce a gaseous flow of NO₂, and Schleicher’s device would convert that NO₂ to NO. Petitioner contended the result was merely the sum of the parts and would have been entirely predictable to a POSITA.

  • Additional Grounds: Petitioner asserted multiple additional anticipation and obviousness challenges. These included anticipation of claims 1-6 over Bullens (Patent 4,221,761), Fine (Application # 2003/0062043), Mergens, and Grosskopf (Patent 3,106,458). Further obviousness grounds were based on various combinations of these references, such as challenging claims 2-5 as obvious over Fine in view of Bullens, and claims 8-12 as obvious over Fine in view of Bullens and Chand.

4. Key Claim Construction Positions

  • Petitioner argued that several key claim terms should be given their broadest reasonable interpretation. The most critical construction was for the term "antioxidant." Petitioner contended that because the claimed chemical reaction is a reduction of NO₂, the term "antioxidant" should be interpreted as a "reducing agent." This construction was central to the invalidity arguments, as much of the prior art explicitly discloses "reducing agents" (e.g., polyarylene ether, ferrous sulfate, ascorbic acid) for converting NO₂ to NO, even if those references do not use the specific term "antioxidant."

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-22 of the ’997 patent as unpatentable.