Patenting diagnostic methods is more challenging in the wake of the U.S. Supreme Court’s Mayo Collaborative Services v. Prometheus Laboratories, Inc., 566 U.S. __ (2012) (Prometheus) and the USPTO’s application of the decision, as set forth in its Guidance Document distributed to patent examiners. Patent examiners are advised to follow the Guidance Document in examining a process claim (e.g., medical method claim) in which a law of nature, a natural phenomenon, or naturally occurring relation or correlation (collectively referred to as a natural principle in the Guidance Document) is a limiting element or step. Thus, a medical diagnostic claim that correlates or relates to a genetic marker or physiological measurement (typical in personalized medicine) is subject to the Guidance Document as the claim necessarily includes an element interpreted by the USPTO as a natural principle.

The Guidance Document provides that if the method claim also includes a new use of a drug in combination with method elements (hereafter a test and treat claim) the claim should not be rejected for failing to satisfy patent-eligibility provided the administration step is more than appending conventional steps, specified at a high level of generality, to a natural principle. Thus, patenting personalized medicine by a test and treat claiming strategy can be a way to protect the technology, when the straight diagnostic method may not be patent-eligible because it fails to satisfy the new patent-eligible standard under Prometheus and the USPTO’s Guidance Document.

Enforcement of a test and treat claim can be challenging as it usually requires two independent actors to perform all steps of the claim to show direct infringement – one actor performing the diagnostic claim elements or steps and a second actor performing the treatment claim elements or steps. Late last summer the Federal Circuit provided a theory under which these claims could be enforced against one actor without direct infringement. In Akamai Technologies, Inc. v. Limelight Networks, Inc., (Akamai) and McKesson Technologies, Inc. v. Epic Systems Corp., (McKesson), __ F.3d __ (Fed. Cir. 2012), the Federal Circuit held that infringement can be found under 35 U.S.C. 271(b) if a party induced others to act with that party or induced others to perform all elements of the claim. In an en banc opinion, the court overruled its prior precedent that held that in order for a single party to be liable for induced infringement, a single entity must perform all elements of the claim. See BMC Resources, Inc. v. Paymentech, L.P., 498 F.3d 1373 (Fed. Cir. 2007). The Federal Circuit reasoned that a party who knowingly induces others to engage in acts that jointly practice the steps of a patented method and those others perform those steps has had precisely the same impact on the patentee as the party who induces the same infringement by a single infringer.

On December 28, 2012, certiorari petitions were filed in both McKesson and Akamai. Petitioners ask the Supreme Court to review and reverse the Federal Circuit’s holding that third party infringement liability can be found in the absence of direct infringement by any party under 35 U.S.C. 271(a). A response is due February 4, 2013 in McKesson and a response in Akamai is due on February 1, 2013. Stay tuned.