Federal Circuit Clarifies the Patentability of Method of Use Claims in the Pharmaceutical Field. Under 35 U.S.C. §101 of the U.S. Patent Act, laws of nature, natural phenomena, and abstract ideas are not patentable subject matter. In the landmark case, Mayo Collaborative Servs. v. Prometheus Labs., Inc., 132 S. Ct. 1289, 566 U.S. 66 (2012), the Supreme Court struck down method claims to optimizing therapeutic efficacy of a drug, leading to concerns surrounding the patentability of pharmaceutical method of use claims. There, the Supreme Court analyzed the claims under a two-step framework to determine patentability under § 101. In step one, the court must determine whether the claims at issue are directed to a patent-ineligible concept. In step two, the court must consider whether the elements of each claim transform the nature of the claim into a patentable application. Under step two, the claims must contain an “inventive concept” that is sufficient to ensure that the patent claims significantly more than the ineligible concept itself. The claims in Mayo required correlating blood levels of certain metabolites with a need to increase or decrease the amount of the drug administered. Under step one, the Court found that the correlation of metabolite levels with the safe and effective use of the drug relied upon a law of nature. Under step two, the Court further found that the remaining claims elements—“administering” the drug and “determining” the metabolite levels—consisted of routine and conventional activity practiced by those of ordinary skill in the art that were insufficient to transform the unpatentable natural law into a patentable application of the newly-discovered correlation. While the Mayo Court distinguished the unpatentable claims in that case from “a typical patent on a new drug or a new way of using an existing drug,” the case left some doubt as to what steps were necessary for a claim to a method of using a drug to be considered patentable.
In Vanda Pharms., Inc. v. West-Ward Pharms. Int’l, Ltd., No. 16-2707, – F.3d – (Fed. Cir. Apr. 13, 2018), the Federal Circuit provided some clarification concerning what types of method of use claims pass muster after Mayo. In Vanda, the Federal Circuit found that method of use claims to an “application” of a natural law were patentable and distinguishable from the “diagnostic” claims in Mayo. The claims in Vanda were to treating a schizophrenia patient with the drug Fanapt® (iloperidone). Certain patients with lower than normal activity for the gene cytochrome P450 2D6 (“CYP2D6”) do not properly metabolize iloperidone, leading to increased blood levels. The dosage of iloperidone must be reduced in these poor metabolizers to prevent potentially severe adverse events. The claims required determining a patient’s metabolic genotype. If the patient has a CYP2D6 poor metabolizer genotype, then the dose of iloperidone administered to the patient is 12 mg per day or less, rather than the normal dose of up to 24 mg per day. Under step one of the Mayo framework, the Federal Circuit found that while the ability of a patient to metabolize the drug depending on their genotype relied upon a law of nature, the claims were not “directed to” a law of nature because the claims included a particular application—specifically, a dosing regimen—based upon the natural relationship. The court did not reach step two of the Mayo analysis because it found that the application of the relationship between iloperidone and CYP2D6 metabolism to treat schizophrenia with specific dosages was a patentably distinct “‘new way of using an existing drug’ that is safer for patients because it reduces the risk” of potentially severe adverse events.
The Federal Circuit distinguished the Vanda claims from Mayo, because the claims in Mayo were essentially diagnostic claims. In other words, the claims in Mayo went to determining whether certain metabolites were present following administration of a drug. The presence of the metabolite above or below a certain level would then “indicate” a need to increase or decrease the dose of the drug administered. The Federal Circuit found that the “indicate” step in Mayo was critical to a finding of unpatentability. Because the claims in Mayo did not actually require adjusting the dose of the drug, they could be infringed if the treating physician determined the metabolite level and merely considered a dose adjustment. In Vanda, however, the claims required a specific dose adjustment that was dependent upon the patient’s metabolic genotype. This requirement of a specific dosing regimen in Vanda moved the claims out of the realm of “diagnostic” claims and into the realm of “a specific method of treatment for specific patients using a specific compound at specific doses to achieve a specific outcome.” Thus, the Federal Circuit found the Vanda claims to be patentably distinct from Mayo.
Because the Federal Circuit found that the claims in Vanda were not directed to a natural law, it did not reach the question of whether the steps of the claims beyond the naturally occurring metabolic relationship would have been routine and conventional to a person of ordinary skill in the art. This approach was sharply criticized by Chief Judge Prost in her dissent. Judge Prost would have found under step one of the Mayo framework that the claims were directed to the natural phenomena of the patient’s ability to metabolize the drug based on their metabolic genotype. She then went on to argue that under step two of the patentability analysis, the “recitation of the specific dosages adds no more than a conventional application of that natural law.” Based on this reasoning, Judge Prost would have found that the claims are directed to a natural law, lack an inventive concept, and, thus, are unpatentable under Mayo.
The key difference between the majority and dissenting opinions in Vanda is whether the dosing regimen steps provide a basis to find that the claims are directed to a practical application and not to a natural law. The majority found that they did and in doing so answered at least one of the lingering questions left unaddressed by Mayo. Going forward, method of use claims in the pharmaceutical field should be held to clear the patentability hurdle if they include such concrete elements as using specific doses of a specific drug to treat a specific disease. Based on Vanda, there should be clarity that these types of claims are safely outside the bounds of an unpatentability finding based on Mayo. It is less clear, however, whether claims to treating a disease with a drug but without reciting a specific dosing regimen go beyond claiming a natural law. West-Ward has requested a rehearing en banc.
For now, the Vanda decision should provide some comfort to innovator pharmaceutical companies that method of use patents to treating a disease with specific doses of a drug are not directed to patent-ineligible subject matter. However, while the Vanda decision is precedential, it is always possible that a different Federal Circuit panel more partial to Judge Prost’s reasoning could reach a different conclusion.