In IPR 2015-01127, PAR Pharmaceuticals, challenged claims 1-11 of USPN 8,404,215 owned by Horizon Therapeutics, LLC on grounds of obviousness over various combinations of six references. Lupin Ltd. and Lupin Pharmaceuticals, Inc. filed another challenge to the claims of the ‘215 patent on the same grounds using the same arguments and evidence as used by PAR. The Board joined the two proceedings and construed the claims-at-issue in accordance with the plain meaning of the recited terms, crediting the unrebutted testimony of Petitioners’ expert in holding the claims unpatentably obvious under 35 U.S.C. § 103(a) over various combinations of the cited art.

The Board found that nitrogen retention disorders, including urea cycle disorders (UCDs), lead to elevated blood levels of ammonia, a toxin, and that nitrogen scavenging drugs treat such disorders by lowering the level of ammonia in the blood. The claims of the ‘215 patent are drawn to methods of administering and dosing a nitrogen scavenging drug to treat the disorders. Claim 1 is illustrative of the claims-at-issue.

  1. A method for adjusting the dosage of a nitrogen scavenging drug in a subject who has previously been administered an initial dosage of the nitrogen scavenging drug, comprising:

a) measuring a fasting blood ammonia level for the subject;

b) comparing the fasting blood ammonia level to the upper limit of normal for blood ammonia level; and

c) administering an adjusted dosage of the nitrogen scavenging drug, wherein the adjusted dosage is greater than the initial dosage if the fasting blood ammonia level is greater than half the upper limit of normal for blood ammonia level.

The Board found that the cited art disclosed treatment of UCDs with nitrogen scavenging drugs whenever the level of blood ammonia exceeded the normal range and credited the art and Petitioners’ expert as establishing that one of ordinary skill in the art would understand to administer a nitrogen scavenging drug whenever blood ammonia exceeded the upper bound of the normal range. Patent Owner did not amend the claims or provide expert testimony, relying instead on its interpretation of the claims as requiring scavenger administration if the blood ammonia level was within the normal range, albeit in the upper half of that range. The Board construed the plain meaning of the words defining the administering step as requiring delivery of the drug whenever the blood ammonia level is greater than the mid-point of the normal range, regardless of whether the measured blood ammonia level is in the upper half of the normal range or exceeds the normal range.

[A] teaching to administer drug when the blood ammonia level is at any level above half the upper limit of normal meets the limitations of Patent Owner’s claims . . . .

Patent Owner exclusively relied on the argument that it would have been unobvious to treat disorders arising from blood ammonia levels found within the normal range of blood ammonia levels. The Board’s claim construction conformed to Occam’s Razor in providing the most parsimonious interpretation of the claims based on the plain meaning of the terms used therein. Patent Owner appears to have run a significant risk in arguing for a nuanced claim construction that did not comport with the plain meaning of the claim terms without support from expert testimony Given its finding that the cited art taught administering nitrogen scavenging drugs to treat UCDs, a form of nitrogen retention disorder, whenever the blood ammonia level exceeded the normal range, the Board held the claims of the ‘215 patent to be obvious under 35 U.S.C. § 103(a) over various combinations of the cited art. It is apparent that Patent Owner’s exclusive reliance on a claim construction at odds with the simplest and most straightforward claim interpretation based on the plain meanings of the claim terms doomed the challenged claims, at least in the absence of persuasive expert testimony.

An interesting procedural note provides insight into some of the criticisms of recent patent eligibility decisions by the Supreme Court. The ‘215 patent claims bear a striking resemblance to Prometheus’s drug optimization claims at issue in Mayo Collab. Serv., Inc. v. Prometheus Labs., Inc., 132 S.Ct. 1289 (2012). As in Prometheus, the claims here involve optimizing dosages administered in known treatment methods. Although the ‘215 patent issued about one year after Prometheus, no post-grant review challenging patent eligibility was mounted. That failure may have arisen because Petitioners did not perceive a threat from the ‘215 patent until it was asserted against them, which occurred about 13 months after issuance. At that time, PGR was no longer available. Petitioners may have thus been limited to an IPR challenge, which is restricted to invalidity arguments under 35 U.S.C. §§ 102 and 103. Faced with that limitation, Petitioners successfully challenged the claim as obvious under § 103(a), which is consistent with an argument made by many critics of Prometheus who contend that the issues troubling the Court in that case could be handled using existing standards for patentability.