INO Therapeutics LLC v. Praxair Distribution Inc.

But for a clerical error to be addressed on remand, the Federal Circuit affirms findings of ineligible subject matter and non-infringement.

August 17, 2019

GENERICally Speaking: A Hatch Waxman Litigation Bulletin

Case NameINO Therapeutics LLC v. Praxair Distribution Inc., 2019 U.S. App. LEXIS 25756 (Fed. Cir. Aug. 27, 2019) (Circuit Judges Prost, Newman, and Dyk presiding; Opinion by Prost, C.J.; Dissenting Opinion by Newman, J.) (Appeal from D. Del., Sleet, J.)

Drug Product and Patent(s)-in-Suit: INOmax® (nitric oxide); U.S. Patents Nos. 8,282,966 (“the ’966 patent”), 8,293,284 (“the ’284 patent”), 8,795,741 (“the ’741 patent”), 8,431,163 (“the ’163 patent”), and 8,846,112 (“the ’112 patent”) (collectively, heart failure or “HF” patents); U.S. Patents Nos. 8,573,209 (“the ’209 patent”), 8,776,794 (“the ’794 patent”), 8,776,795 (“the ’795 patent”), 9,265,911 (“the ’911 patent”), and 9,295,802 (“the ’802 patent”) (collectively, the delivery system infrared patents or “DSIR” patents)

Nature of the Case and Issue(s) Presented: Inhaled nitric oxide (“iNO”) is a gas that is well known in the prior art. The FDA approved the NDA for iNO in 1999. Since at least the early 1990s, iNO gas has been used to treat infants experiencing hypoxic respiratory failure. Hypoxic respiratory failure is a condition where oxygen levels in the blood are too low. Nitric oxide functions to dilate blood vessels in the lungs and can thereby improve blood oxygenation. A dose of 20 ppm iNO was also well known in the prior art for treatment of hypoxic respiratory failure in infants. Treatment using iNO was not without its side effects. Neonates with a congenital heart condition-known as left ventricular dysfunction (“LVD”) were at an increased risk of pulmonary edema when treated with iNO gas. Beginning in 2009, INO Therapeutics began pursuing patents based on this observation. Eventually, it obtained the five HF patents. INO Therapeutics also obtained patents related to devices and methods for providing iNO gas to patients via gas cylinders, namely, the DSIR patents. INO Therapeutics and Mallinckrodt ultimately merged and Mallinckrodt is the exclusive supplier of iNO gas in the U.S.

Praxair is an industrial gas company seeking to sell generic iNO gas cylinders. Praxair filed an ANDA seeking approval to market Noxivent, a generic form of nitric oxide gas for inhalation. In addition, Praxair acquired a company that developed a gas delivery system, called the NOxBOXi iNO system.

Mallinckrodt sued Praxair in 2015. The case proceeded to a seven-day bench trial. In September 2017, the district court issued a memorandum and order concluding that the HF patents were ineligible and the DSIR patents were not infringed. Plaintiffs appealed and the Federal Circuit affirmed-in-part, reversed-in-part, and remanded.

Why Praxair Prevailed: Mallinckrodt’s appeal raises three issues: (i) the district court erred by concluding that the asserted claims of the HF patents are ineligible under § 101; (ii) the district court erroneously construed the term “verify” when analyzing whether Praxair’s proposed gas cylinder infringes the DSIR patents; and (iii) the district court improperly entered judgment on certain unasserted claims. The Federal Circuit addressed each in turn.

First, the Federal Circuit affirmed the finding that the HF patents were ineligible. The treatment of infants experiencing hypoxic respiratory failure with iNO gas has existed for decades. The inventors observed an adverse event that iNO gas causes for certain patients. The patent claim does no more than add an instruction to withhold iNO treatment from the identified patients; it does not recite giving any affirmative treatment for the iNO-excluded group, and so it covers a method in which, for the iNO-excluded patients, the body’s natural processes are simply allowed to take place. Thus, the asserted claim is directed to a natural phenomenon. The claim, apart from the natural phenomenon itself, involves only well-understood, routine, and conventional steps.

Second, the DSIR patents require the device to “verify one or more of the gas identification, the gas concentration and that the gas is not expired.” The term “verify” was never formally construed by the district court, which applied its plain and ordinary meaning. It found that the system does not “verify” the gas data when one simply takes a meter from Mallinckrodt’s gas cylinder (containing data about the gas from the manufacturer) and uses it with a Praxair gas cylinder (which does not contain a meter with gas data). Put another way, the district court interpreted the claim term to require that the gas delivery system verify data about the actual gas in the “gas source.” Malinckrodt takes the position that the DSIR patent claims are practiced when any iNO cylinder is combined with a circuit storing gas data even if the data is unrelated to the particular gas in the cylinder. Relying on the claim language itself, the Fedreal Circuit affirms the district court’s infringement analysis. The DSIR patent claim recites a “gas delivery device” with “a gas source” to provide iNO “therapy gas.”  The “gas” throughout the claim consistently refers to the specific contents of the “gas source” administered to the patient. Thus, “gas data” relates to the actual gas inside the cylinder. Moreover, Mallinckrodt’s expert testified that the NOxBOXi’s gas data does not come from the gas source.

Third, the Federal Circuit found that the district court did not limit its ruling to the asserted claims before it. Instead, the district court erroneously made a blanket ruling that each Mallinckrodt patent in its entirety was invalid or not infringed. Therefore, the Federal Circuit remanded the case back to the district court to correct this “clerical” error.

Judge Newman wrote a separate opinion concurring-in-part and dissenting-in-part. Judge Newman concurred in correction of the technical error, but dissented from the majority’s rulings that the HF claims at issue were ineligible under Section 101. The method that is described and claimed does not exist in nature; it was designed by and is administered by humans. According to Judge Newman, the majority improperly separates the claims into old and new steps, describes some claim steps as a “natural phenomenon” and some steps as “well-understood, routine, and conventional steps,” and avoids the requirement that a claimed invention is considered as a whole. Therefore, the majority opinion directly contradicts Federal Circuit precedent applying section 101 to methods of medical treatment. While Judge Newman admits that Mallinckrodt’s method of treatment may or may not pass the tests of sections 102 or 103, the majority’s opinion finding these claims ineligible adds to the inconsistency and unpredictability of this area of patent-supported innovation.

Oren D. Langer


Managing Partner, New York Office
Member of Executive Board

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