Litigation Details for INO Therapeutics LLC v. Praxair Distribution Inc. (Fed. Cir. 2017)

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INO Therapeutics LLC v. Praxair Distribution Inc. (Fed. Cir. 2017)

Docket		Date Filed	2017-10-10
Court	Court of Appeals for the Federal Circuit	Date Terminated	2019-08-27
Cause		Assigned To
Jury Demand		Referred To
Patents	8,282,966; 8,293,284; 8,431,163; 8,573,209; 8,776,794; 8,776,795; 8,795,741; 8,846,112; 9,265,911; 9,295,802
Link to Docket	External link to docket

Details for INO Therapeutics LLC v. Praxair Distribution Inc. (Fed. Cir. 2017)

Date Filed	Document No.	Description	Snippet	Link To Document
2017-10-10				External link to document

INO Therapeutics LLC v. Praxair Distribution Inc. (18-1019): Litigation Summary, Patent Claims, and Section 101 Analysis

Last updated: November 9, 2026

The Federal Circuit affirmed the invalidity of INO Therapeutics’ patents covering inhaled nitric oxide treatment for patients at risk of pulmonary edema because of left ventricular dysfunction. The court held that the asserted claims were directed to a natural law, namely the relationship between nitric oxide administration and pulmonary edema risk, and did not contain an inventive concept sufficient to satisfy 35 U.S.C. § 101. The decision weakened patent protection around nitric oxide treatment protocols and limited INO Therapeutics’ ability to use the patents against competing delivery systems. INO Therapeutics LLC v. Praxair Distribution Inc., 938 F.3d 1320 (Fed. Cir. 2019).

What was the INO Therapeutics v. Praxair dispute about?

The case involved patents covering the administration of inhaled nitric oxide to patients with pulmonary hypertension or related cardiopulmonary conditions. INO Therapeutics alleged that Praxair’s nitric oxide delivery products infringed claims directed to identifying patients who could develop pulmonary edema after nitric oxide treatment and withholding treatment from patients with left ventricular dysfunction.

Nitric oxide is a pulmonary vasodilator. It can reduce pulmonary vascular resistance, but its use may create risks for certain patients, including patients with left ventricular dysfunction. INO’s patents attempted to claim a treatment protocol based on that clinical relationship.

The dispute reached the Federal Circuit after the U.S. District Court for the District of Delaware held the asserted claims invalid under § 101.

Item	Details
Case	INO Therapeutics LLC v. Praxair Distribution Inc.
Federal Circuit docket	No. 18-1019
Federal Circuit citation	938 F.3d 1320
Court	U.S. Court of Appeals for the Federal Circuit
Decision	2019
Technology	Inhaled nitric oxide treatment and delivery
Patents at issue	U.S. Patent Nos. 8,776,865 and 8,795,966
Primary legal issue	Patent eligibility under 35 U.S.C. § 101
Outcome	Claims held patent-ineligible
Commercial products	Nitric oxide delivery systems, including INOmax-related systems

What patents protected the nitric oxide treatment protocol?

The litigation concerned U.S. Patent Nos. 8,776,865 and 8,795,966. The patents addressed the selection and treatment of patients receiving inhaled nitric oxide.

The central claim concept required:

1. Identifying a patient at risk of developing pulmonary edema after nitric oxide administration.
2. Determining whether the patient had left ventricular dysfunction.
3. Administering inhaled nitric oxide only when the patient did not have the specified cardiac condition.

The patents did not claim nitric oxide as a new chemical compound. They also did not claim a new delivery apparatus in the conventional mechanical sense. Their value was concentrated in the treatment-selection protocol and the clinical decision rule.

What clinical relationship did the patents claim?

The patents relied on the relationship between nitric oxide and cardiovascular physiology. Nitric oxide can dilate pulmonary blood vessels. In a patient with impaired left ventricular function, that change can increase pulmonary blood flow without adequate left-heart accommodation, potentially causing pulmonary edema.

The Federal Circuit characterized this relationship as a natural law. The court treated the patient-identification and treatment steps as instructions for applying that relationship in clinical practice rather than as a patent-eligible technological improvement.

Why did the Federal Circuit find the claims ineligible under Section 101?

The Federal Circuit applied the two-step framework from Mayo Collaborative Services v. Prometheus Laboratories, Inc. and Alice Corp. v. CLS Bank International.

Step one: Were the claims directed to a natural law?

The court held that the claims were directed to the natural law connecting nitric oxide administration, left ventricular dysfunction, and pulmonary edema.

The court rejected the argument that the claims were directed to a patentable treatment method merely because they required a physician or healthcare provider to perform specific clinical steps. The claimed steps, in the court’s view, were conventional actions used to observe and apply the underlying physiological relationship.

The Federal Circuit distinguished the case from Vanda Pharmaceuticals Inc. v. West-Ward Pharmaceuticals International Ltd., where the claims required adjusting a drug dose based on a patient’s genotype. In Vanda, the treatment step itself was tied to a specific patient outcome and dosage decision. In INO Therapeutics, the court found that the claims principally instructed practitioners to recognize a risk and avoid treatment in the relevant patient population.

Step two: Did the claims contain an inventive concept?

The court held that they did not. The asserted claims used conventional activities:

• Identifying a patient.
• Determining whether the patient had left ventricular dysfunction.
• Administering or withholding inhaled nitric oxide.

The specification did not provide a new diagnostic technique, new nitric oxide formulation, new delivery mechanism, or new method for measuring left ventricular function. The court therefore found that the claims added routine steps to a natural law.

Judge Pauline Newman dissented. Her dissent viewed the claims as directed to a concrete therapeutic method rather than an abstract recitation of a physiological relationship. The dissent argued that the claims required a practical treatment protocol that improved patient safety.

What was the final litigation outcome?

The Federal Circuit affirmed the district court’s judgment that the asserted claims were invalid under § 101. Because the claims were held patent-ineligible, the court did not need to reach the full scope of infringement, claim construction, or other invalidity issues.

Litigation stage	Result
District Court for the District of Delaware	Asserted claims held invalid under § 101
Federal Circuit appeal	Judgment affirmed
Patent eligibility	Failed
Infringement determination	No commercially meaningful infringement judgment after invalidity ruling
Patent enforceability	Claims could not be enforced
Further Supreme Court review	No reported Supreme Court reversal

The decision eliminated the immediate litigation leverage associated with the asserted claims. Praxair therefore avoided exposure to damages or an injunction based on those claims.

How strong was the INO Therapeutics patent estate?

The estate had a narrow technical focus and substantial eligibility risk. Its claims were built around a clinical relationship rather than a novel molecule, formulation, or delivery platform.

Patent protection category	Position after INO v. Praxair
Nitric oxide compound	Not the focus of the asserted patents
Treatment-selection protocol	Invalidated under § 101
Patient-risk identification	Treated as conventional clinical activity
Nitric oxide formulation	Not the central issue
Delivery apparatus	Not the basis of the Federal Circuit’s holding
Manufacturing process	Not adjudicated in the decision
Method of use	Vulnerable where tied to the natural law
Diagnostic testing technology	No specific new testing technology sustained
Composition-of-matter protection	Not implicated by the decision

The decision illustrates a major distinction in pharmaceutical patent strategy. A claim directed to a new composition, device architecture, or manufacturing process may withstand eligibility scrutiny even when a treatment method fails. A claim that identifies a biological correlation and instructs physicians to act on it faces greater § 101 exposure if the remaining steps are routine.

Did the case involve Orange Book patents or FDA exclusivity?

The appeal was not an Orange Book listing dispute. The Federal Circuit opinion did not decide whether either patent was listed in the FDA Orange Book, and the decision did not address an Abbreviated New Drug Application, a Paragraph IV certification, or a Hatch-Waxman litigation framework.

INOmax, an inhaled nitric oxide product, received FDA approval before the litigation. The patent dispute, however, concerned the enforceability of treatment-related patents rather than the regulatory approval of nitric oxide itself.

Regulatory issue	Status in the case
FDA approval of inhaled nitric oxide	Existing product approval
Orange Book listing dispute	Not decided
Paragraph IV challenge	Not reported as the basis of this appeal
505(b)(2) litigation	Not the appellate issue
Biologics license application	Not applicable
Biosimilar pathway	Not applicable
Device clearance dispute	Not the basis of the decision

Were there Paragraph IV challenges or generic-launch issues?

The case was not a conventional generic-drug launch case. Praxair was a commercial supplier and distributor of nitric oxide delivery products, not a generic-drug applicant challenging an Orange Book-listed patent through a Paragraph IV certification.

The commercial risk instead concerned competition in nitric oxide treatment and delivery systems. If the patents had survived, INO Therapeutics could have pursued infringement remedies against competing products or treatment protocols. After invalidation, competitors faced materially lower patent risk for using the claimed patient-selection approach.

A future competitor could still face exposure under other patents covering:

• Nitric oxide delivery hardware.
• Gas blending and concentration control.
• Patient monitoring.
• Alarms and safety systems.
• Tubing, connectors, and ventilator integration.
• Manufacturing and purification.
• Product-specific formulations or storage systems.

The Federal Circuit’s decision did not invalidate every patent that could cover inhaled nitric oxide. It invalidated the asserted claims in the patents before the court.

What formulation and delivery patents remained relevant?

The opinion focused on treatment-method eligibility. It did not establish that every nitric oxide formulation or delivery-system patent was invalid.

Potentially stronger patent categories include claims directed to measurable technical improvements, such as:

Delivery-system claims

A delivery patent may be stronger when it claims a specific control architecture, gas-mixing arrangement, sensor configuration, calibration method, or feedback loop. Those claims are more likely to be evaluated as technological improvements rather than instructions to apply a physiological principle.

Formulation and storage claims

Claims directed to stabilized nitric oxide mixtures, storage conditions, container materials, impurity control, or shelf-life improvements may present a different eligibility profile. Such claims can be tied to physical chemistry and manufacturing performance.

Manufacturing claims

Processes that reduce nitrogen dioxide formation, improve gas purity, or increase production consistency may provide separate protection from the invalidated treatment claims.

Monitoring and safety claims

A monitoring claim must still avoid merely instructing a practitioner to observe a patient and apply a natural law. A claim tied to a particular sensor arrangement or automated control operation has a stronger technical foundation.

What was the impact on licensing and settlement leverage?

The appellate decision reduced the value of the asserted patent claims as licensing assets. A patent owner generally has greater leverage when its claims cover a product’s core composition or a necessary technical component. These claims instead covered a clinical protocol that the court held ineligible.

The reported appellate decision did not resolve a licensing agreement or settlement between INO Therapeutics and Praxair. It also did not report a royalty-bearing cross-license or a covenant not to sue.

The decision may still affect licensing negotiations involving adjacent nitric oxide technologies. Parties evaluating a portfolio would likely separate:

• Invalidated clinical decision-rule patents.
• Surviving apparatus patents.
• Manufacturing patents.
• Product-specific patents.
• Regulatory exclusivity.
• Trade-secret protection for production and quality control.

What generic entry and competitive risks followed the decision?

The most direct effect was removal of the asserted patents as a barrier to competing nitric oxide treatment protocols. The decision did not create automatic market entry rights because competitors could remain subject to other patents, FDA requirements, procurement contracts, and technical qualification requirements.

Commercial entry risk remained highest in areas requiring:

• FDA-compliant nitric oxide products.
• Reliable gas delivery at therapeutic concentrations.
• Integration with ventilators and patient monitors.
• Control of nitrogen dioxide and oxygen exposure.
• Hospital validation and safety testing.
• Manufacturing scale and quality systems.

The ruling reduced legal risk around the specific treatment protocol but did not remove regulatory or engineering barriers.

How does INO Therapeutics v. Praxair compare with Vanda Pharmaceuticals?

Issue	INO Therapeutics v. Praxair	Vanda v. West-Ward
Therapy	Inhaled nitric oxide	Iloperidone
Claimed relationship	Nitric oxide risk and left ventricular dysfunction	Genotype, metabolism, and drug dosage
Claimed action	Treat only patients outside the risk group	Adjust dosage based on genotype
Federal Circuit result	Claims ineligible	Claims eligible
Key distinction	Natural-law application with conventional steps	Specific treatment adjustment tied to patient characteristics
Patent strategy lesson	Avoid claiming only a biological correlation and routine clinical response	Claim a concrete therapeutic intervention linked to a patient-specific result

The comparison is important for pharmaceutical patent drafting. A method claim is more likely to survive if it recites a specific therapeutic action that changes based on a measured patient characteristic. A claim that merely identifies a natural risk and instructs the practitioner to avoid treatment may be vulnerable.

What is the current patent and litigation significance of the case?

INO Therapeutics v. Praxair remains relevant to patent prosecution and litigation involving:

• Personalized medicine.
• Diagnostic-treatment combinations.
• Biomarker-based prescribing.
• Drug safety protocols.
• Clinical decision support.
• Natural-law arguments under § 101.
• Patents covering patient selection.

The decision does not prohibit all medical treatment patents. It indicates that eligibility depends on claim structure and technical content. Patent owners should distinguish between:

1. A claim that identifies a natural relationship and applies routine clinical steps.
2. A claim that uses a new test, a new device, a new formulation, or a specific therapeutic adjustment to produce a technical improvement.

Key Takeaways

• The Federal Circuit affirmed invalidity of INO Therapeutics’ asserted claims in 2019.
• The patents covered inhaled nitric oxide treatment decisions involving pulmonary edema risk and left ventricular dysfunction.
• The court held that the claims were directed to a natural law under § 101.
• Conventional patient identification, diagnosis, and treatment steps did not supply an inventive concept.
• The case was not an Orange Book or Paragraph IV dispute.
• The decision did not invalidate all nitric oxide delivery, formulation, or manufacturing patents.
• The ruling reduced INO Therapeutics’ enforcement and licensing leverage against competing treatment protocols.
• Medical patents are stronger when they claim a concrete technical improvement or a specific therapeutic intervention rather than a biological correlation alone.

FAQs

What did INO Therapeutics sue Praxair for?

INO Therapeutics asserted patent claims covering inhaled nitric oxide treatment protocols for patients at risk of pulmonary edema due to left ventricular dysfunction.

What patents were involved in INO Therapeutics v. Praxair?

The case involved U.S. Patent Nos. 8,776,865 and 8,795,966.

Did Praxair win the Federal Circuit appeal?

Yes. The Federal Circuit affirmed the judgment that the asserted claims were invalid under 35 U.S.C. § 101.

Did the decision affect FDA approval of INOmax?

No. The appellate decision concerned patent eligibility and did not revoke or modify FDA approval of an inhaled nitric oxide product.

Is inhaled nitric oxide a biologic subject to biosimilar competition?

No. Inhaled nitric oxide is a drug product and gas therapy, not a biologic subject to the biosimilar pathway. Competition depends on FDA drug regulation, product equivalence, delivery technology, and applicable patents.

References

1. INO Therapeutics LLC v. Praxair Distribution Inc., 938 F.3d 1320 (Fed. Cir. 2019).

2. Alice Corp. Pty. Ltd. v. CLS Bank International, 573 U.S. 208 (2014).

3. Mayo Collaborative Services v. Prometheus Laboratories, Inc., 566 U.S. 66 (2012).

4. Vanda Pharmaceuticals Inc. v. West-Ward Pharmaceuticals International Ltd., 887 F.3d 1117 (Fed. Cir. 2018).

5. U.S. Patent No. 8,776,865. “Method and apparatus for delivering nitric oxide to a patient.” Issued July 15, 2014.

6. U.S. Patent No. 8,795,966. “Method and apparatus for delivering nitric oxide to a patient.” Issued August 5, 2014.