INOmax® (nitric oxide)
Case Name: Mallinckrodt plc v. Airgas Therapeutics LLC, Civ. No. 22-1648 (RGA), 2025 WL 2410306 (D. Del. Aug. 20, 2025) (Andrews, J.)
Drug Product and Patent(s)-in-Suit: INOmax® (nitric oxide); U.S. Patent Nos. 8,776,794 (“the ’6794 patent”), 8,776,795 (“the ’795 patent”), 9,279,794 (“the ’9794 patent”), 9,919,118 (“the ’118 patent”), and 10,773,046 (“the ’046 patent”)
Nature of the Case and Issue(s) Presented: Mallinckrodt’s (“MNK”) patents cover INOmax and its delivery system, DSIR Plus, which comprise products that administer inhaled nitric oxide gas (“iNO”) in a hospital setting to neonates and children suffering from hypoxic respiratory failure. The patents-in-suit claim methods of treating patients using iNO while reducing the risk of adverse effects. Four of the patents-in-suit are listed in the Orange Book: the ’741 patent, the ’6794 patent, the ’795 patent, and the ’9794 patent. Airgas submitted an ANDA seeking FDA approval to make and sell generic INOmax and a delivery system, called “Ulspira” and “Ulspira TS,” respectively. MNK filed suit in Nov. 2022. MNK filed a motion for a preliminary injunction, which the court denied. Airgas received approval for its ANDA in July 2023. Before the court were MNK and Airgas’s motions for summary judgment and Daubert motions.
The court’s rulings: Summary Judgment. MNK moved for summary judgment that the hypothetical negotiation date for a reasonable royalty was November 2022, the date Airgas amended its ANDA to include paragraph IV certifications for the patents listed in the Orange Book for INOmax. In response, Airgas argued the proper date was November 2023, the date Airgas launched Ulspira. While true that filing an ANDA is an “artificial” act of infringement that allows the NDA holder to file a patent infringement suit, “The hypothetical negotiation contemplating a willing licensor-willing licensee negotiation on the eve of infringement indicates the negotiation is based on a scenario where an infringer needs a license for its imminent launch.” An ANDA holder does not need a license to file its ANDA, even if that ANDA is found to infringe. But the ANDA holder would need a license to launch the infringing product. Therefore, the appropriate hypothetical negotiation date was November 2023.
Next, MNK sought summary judgment that certain asserted claims were not invalid as obvious. MNK argued that Airgas’s expert failed to show there was a motivation to combine prior art references. The motion was denied concerning asserted patents related to the ’6794 and ’795 patents. Airgas’ expert opined that those patents were obvious in light of two of MNK’s earlier-released iNO delivery devices. But the court found there was a genuine dispute of material fact relating to claim scope and the “gas data” limitation that rendered summary judgment relating inappropriate. With respect to the asserted claims of the ’9794 and ’118 patents, Airgas’s expert acknowledged that MNK’s prior art delivery devices did not contain the “determining an actual concentration” element, but rather opined that it would have been obvious to modify those devices to include the missing element. The dispute came down to whether the problem with MNK’s prior art devices (recalculating the slope for each calibration) was known to a POSA. The court found no dispute that the source code was not publicly available and that if a POSA did not know of the problem, there would have been no motivation to fix it, and granted summary judgment.
Next, Airgas moved for summary judgment that it did not infringe claim 7 of the ’795 patent. Specifically, Airgas argued its Ulspira TS device did not perform the claimed “verify[ing] ... the gas concentration” limitation. Even though the court credited Airgas that “Ulspira TS can produce a false positive, that does not preclude the possibility that Ulspira TS can produce a true positive (that is, correctly ‘verify ... the gas concentration’).” Therefore, there is a dispute of material fact at least as to whether Ulspira TS infringes, which precluded summary judgment. The court also denied Airgas’s motion with respect to the ’046 patent. Airgas argued Ulspira TS’ pre-use check performance test did not deliver NO gas to a patient and it therefore could not “calculate a delivery concentration.” But the court found that the claims did not require that the measured gas concentration be delivered to a patient, and therefore that Airgas had not met its burden to show that there were no disputes of material fact and that as a matter of law it did not infringe this element.
Daubert. MNK moved to exclude three parts of testimony from Airgas’ damages expert: his opinions on the hypothetical negotiation, non-infringing alternatives, and design-arounds. The motion was denied with respect to the hypothetical negotiation given the above-referenced summary judgment motion. Regarding non-Infringing alternatives, the expert opined that another competitor’s, Praxair, iNO and delivery products (available at the time of the hypothetical negotiation) were non-infringing alternatives that would have influenced the hypothetical negotiation. MNK disagreed because the patent claims in this case are different from those in the Praxair litigation (which were found not to infringe). The court found: “To the extent Mr. Hofmann would testify that the prior litigation determined anything about the non-infringing status of any claims other than the ones that were at issue, I would exclude that. Since, as I explain below, he has other bases for his non-infringing alternatives opinion, I do not grant Mallinckrodt’s motion to exclude all of Mr. Hofmann’s non-infringing alternatives testimony. Finally, the court granted MNK’s motion with respect to the expert’s design-around opinions. The court found that the expert considered design-arounds, but he gave no analysis as to the price of any of them, which rendered his opinion “methodologically unsound.”
Next, Airgas moved to exclude the testimony of MNK’s damages expert. The expert’s infringement “Scenario 1” contemplated that if at least one of the asserted Orange Book patents was found to be infringed by Airgas, the FDA approval date would be reset to the last expiration date of the infringed patent(s), which would delay Airgas’ commercial launch, and corresponding profits, of Ulspira. Airgas took issue with the fact that the expert failed to apportion value to the infringing features of Airgas’s product. The court agreed that the MNK expert’s Georgia-Pacific analysis did not effectively apportions the patented and unpatented portions of Airgas’ accused device. It also did not find that the expert considered incremental value added by the patented invention to the infringing product under her analysis. Therefore, the court excluded the expert’s testimony concerning Scenario 1. The next issue concerned “whether the upper range of MNK’s damages expert’s] reasonable royalty is, in fact, a reasonable royalty or if it is lost profits in sheep’s clothing.” “While MNK is correct that an expert can use lost profits to inform their reasonable royalty analysis, that does not mean that an expert can pass off lost profits as a reasonable royalty without the required lost profits analysis.” This testimony was found unreliable and was excluded.
Next, MNK moved to exclude Airgas’s expert’s non-infringing alternatives testimony. He opined that that a Praxair product, NOxBOXi, was a non-infringing alternative to Ulspira TS, and that combining portions of NOxBOXi with Airgas’ Ulspira TS product would also be non-infringing. The court found this testimony permissible and any holes can be explored via cross-examination.
Next, Airgas moved to exclude certain testimony of MNK’s FDA regulatory law expert. Because the only purpose of the testimony at issue was to support MNK’s damages expert’s opinion regarding Scenario 1, and because that testimony had been excluded, the court found the regulatory law expert’s opinion irrelevant and granted the motion. MNK moved to exclude certain testimony of Airgas’s FDA regulatory law expert, which responded to its regulatory law expert. Because the latter was excluded, so was the former.
Finally, MNK moved to strike two non-infringement theories that it alleged Airgas raised for the first time in Airgas’ summary judgment briefing. The relevant claim limitation required an accused device to “verify ... gas data.” First, MNK argued that Airgas previously focused its non-infringement allegations on “gas data,” but switched to focus on “verify.” The court found that Airgas adequately disclosed its “verify” non-infringement theory at least in its contentions, “which is exactly what Airgas allege[d] in its motion for summary judgment.” Second, MNK moved to strike Airgas’ theory that Ulspira TS did not deliver nitric oxide “to a patient” in a way that infringed the ’046 patent claims. This too was denied.
