From The Field

April 15, 2020

In 2014, the Supreme Court strengthened the requirement for patent claims to be definite.  It held that claims, interpreted in light of the specification and prosecution history, must “inform those skilled in the art about the scope of the invention with reasonable certainty.”  Nautilus, Inc. v. Biosig Instruments, Inc. 572 U.S. 898, 910 (2014).  Last week, in Nevro Corp. v. Boston Scientific Corporation, 2020 WL 1802794 (Fed. Cir. 2020), the Federal Circuit clarified the outer boundaries of that requirement.

The technology at issue in Nevro involved spinal cord stimulation techniques to alleviate pain.  Specifically, the asserted patents purported to improve on the prior art by not relying on paresthesia (tingling sensations) to mask pain.  A representative system claim required “means for generating a paresthesia-free therapy signal.”  Nevro at *2 (emphasis in original).  Similarly, a representative method claim recited, in its preamble, “without relying on paresthesia or tingling to mask the patient’s sensation of the pain.”  Id. (emphasis in original).

The district court held that the system and device claims, but not the method claims, were indefinite.  It noted that “whether a signal produces paresthesia depends on a patient’s response to a signal; the same signal that produces paresthesia in one patient may not produce paresthesia in another patient.”  Nevro Corp. v. Boston Scientific Corporation 2018 WL 4676501, *3 (N.D. Cal. 2018).  The district court reasoned that, “depending on the characteristics of the patient who uses a spinal cord stimulation system, the same system would either infringe or not infringe the asserted system patents.”  Id.  Therefore, “a skilled artisan cannot identify the bounds of these claims with reasonable certainty.”  Id.  By contrast, the district court concluded that the method claims were not indefinite.  It reasoned that, despite variations among patients, “a skilled artisan would be able to quickly determine whether a signal generates paresthesia for any given patient.”  Id. at *4. 

The district court’s basis for distinguishing between the system and method claims for purposes of indefiniteness can be understood, if at all, as one of timing of infringement knowledge.  Because infringement of the method claim, in the district court’s view, could be adequately assessed when performing the method, the patient-specific nature of paresthesia’s presence or absence was not a problem.  However, because a system (or device) exists prior to its use, the district court required that a skilled artisan also be able to know whether a particular system infringes in advance, i.e., prior to that system being used on a particular patient.  And that, reasoned the district court, was not possible given the patient-dependent nature of infringement.

The Federal Circuit rejected such a distinction between the method claims on the one hand and the system (and device) claims on the other.  Specifically, it rejected the idea that infringement of a system claim must be knowable prior to that system’s use for that claim to be definite: “Definiteness does not require that a potential infringer be able to determine ex ante if a particular act infringes the claims.”  2020 WL 1802794 at *3.  It held that the system and device claims, along with the method claims, were sufficiently definite.

Author: Michael Mauriel