The US Court of Appeals for the Federal Circuit affirmed a district court finding that a patented method for treating schizophrenia was not subject matter ineligible under 35 USC § 101. Vanda Pharmaceuticals Inc. v. West-Ward Pharmaceuticals Intl. Ltd., Case No. 16-2707; -2708 (Fed. Cir., Apr. 13, 2018) (Lourie, J) (Prost, CJ, dissenting).

Vanda Pharmaceuticals owns a patent relating to a method of treating schizophrenia patients with iloperidone. The cytochrome P450 2D6 gene (CYP2D6) encodes an enzyme known to metabolize iloperidone. Expression of this gene varies among individuals, and thus some patients with lower than normal CYP2D6 are poor metabolizers of iloperidone. These patients are more at risk for a side effect known as QTc prolongation—a life-threatening ventricular arrhythmia. The patent teaches that treatment of a patient who has lower CYP2D6 activity with iloperidone can be accomplished more safely by administering a lower dose of the drug than would be administered to a person who has normal CYP2D6 enzyme activity. The patented method requires the steps of (1) determining the patient’s CYP2D6 metabolizer genotype by (a) obtaining a biological sample and (b) performing a genotyping assay, and (2) administering specific dose ranges of iloperidone depending on the patient’s CYP2D6 genotype.

West-Ward Pharmaceuticals filed an abbreviated new drug application seeking approval of a generic version of a drug sold by Vanda, prompting Vanda to file a lawsuit. In response, West-Ward challenged the subject matter eligibility of the patent claims based on § 101. Following a bench trial, the district court analyzed the asserted claims using the Alice/Mayo two-step framework. First, the district court found that the asserted claims depended upon laws of nature, specifically, “the relationship between iloperidone, CYP2D6 metabolism, and QTc prolongation.” In the second step of the eligibility analysis, however, the district court found that the asserted claims transformed the underlying law of nature into a patent-eligible application through the claim limitations—“conducting CYP2D6 genotyping tests to determine the appropriate dose of iloperidone to reduce QTc-related risks.” As a result, the district court found the claims patent eligible. West-Ward appealed.

West-Ward argued that the district court erred in determining that the asserted claims were valid under the two-step Alice/Mayo framework. Vanda argued that while the district court’s ultimate conclusion was correct, it had erred by not finding the asserted claims patent eligible under both steps of Alice/Mayo. The Federal Circuit agreed with Vanda. The Court explained that the claims were not directed to a patent ineligible concept at step one, and thus the Court need not even address step two of the inquiry. The Court also concluded that the asserted claims were directed to “a specific method of treatment for specific patients using a specific compound at specific doses to achieve a specific outcome.”

In reaching its decision, the Federal Circuit noted that, conceptually, the asserted claims cover very similar subject matter to the claims that were invalidated by the Supreme Court of the United States’ 2012 decision in Mayo Collaborative Services v. Prometheus Laboratories, Inc. (IP Update, Vol. 15, No. 3), as both sets of claims generally relate to optimizing the therapeutic efficacy of a drug by determining the relative presence of a biomarker in a patient sample prior to dosing. Several crucial differences resulted in the Court’s finding that Vanda’s patent claims were eligible, however. First, although the claim at issue in Mayo recited administering a drug to a patient, the claim considered as a whole was not directed to a novel method of treating a disease—which Vanda’s claims were. Second, the claims in Mayo did not require that the doctor actually use a natural relationship to determine the appropriate dose. The Court emphasized the importance of the end result: the observation or detection of a relevant biomarker for the purpose of optimizing therapeutic efficacy, like that at issue in Mayo, is not patent eligible, but the specific method of treatment that is based on this optimization, like that in the current case, is patent eligible.

Chief Judge Prost dissented, arguing that the asserted patent claims were directed to a law of nature and that the majority’s “efforts to distinguish Mayo cannot withstand scrutiny.” In her view, the majority analysis of Alice/Mayo step one “conflates the inquiry at step one with the search for an inventive concept at step two.”

Practice Note: Based on Prost’s dissent, this case may be headed for en banc review. For now, it appears that a key to surviving a § 101 challenge in connection with personalized medicine claims—i.e., claims relating to tailored use of drugs based on predicted patient outcomes—is to include active steps that require the doctor to actually use the predictive “natural relationship” to determine a specific treatment regimen for a specific disease.

On May 15, 2018, Judge Bryson, sitting by designation in the US District Court for the District of Delaware in Pernix Ireland Pain Ltd. et al. v. Alvogen Malta Operations Ltd., relied on Vanda to find that eligibility challenged claims directed to pain treatment did not encompass unpatentable subject matter since they were not directed toward a law of nature:

[Two claims] each recites a “method of treating pain in a patient having mild or moderate hepatic impairment,” and teaches using a specific extended release formulation of hydrocodone bitartrate that has a particular release profile. Although the inventions recited in those claims were based upon a natural law—the physiological response to hydrocodone in individuals with or without mild or moderate hepatic impairment—the claims do more than merely report those physiological responses. Rather . . . the claims asserted in this case describe a specific dosing regimen to treat a specific condition based on the patient’s medical status.