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Federal Circuit Vacates PTAB’s Final Written Decisions Because The Board Erred In Its Obviousness Analysis
08/01/2023Medtronic, Inc., asserted U.S. Patent Nos. 8,626,314 and 8,036,756 against Axonics, Inc., in a patent infringement lawsuit. In response, Axonics challenged various claims of the Medtronic patents for obviousness in inter partes reviews (IPRs). In both IPRs, the Patent Trial and Appeal Board concluded that Axonics had failed to prove any of the challenged claims unpatentable. Axonics appealed. On July 10, 2023, the U.S. Court of Appeals for the Federal Circuit (“CAFC”) issued an opinion vacating the Board’s final written decisions in both IPRs.
The “Field of the Invention” section of the two patents states that “[t]his invention relates generally to a method and apparatus that allows for stimulation of body tissue, particularly sacral nerves.” The ’314 patent at 1:34-36. The patents attempt to address the “need in the art for permanently implantable electrical sacral nerve stimulation lead[s]” with certain properties. Id. at 5:34-44.
The “Summary of the Invention” section, however, is broader: “The present invention recognizes and provides a solution to the problems associated with implanting and maintaining electrical leads in body tissue, particularly muscle tissue to maintain one or more lead electrode in relation to a particular body site, through use of minimally invasive implantation techniques.” Id. at 5:48-53. More importantly, none of the claims in either patent mentions or is limited to sacral nerves.
In its two petitions, Axonics argued, among other things, that the challenged claims in both patents are unpatentable under 35 U.S.C. § 103 for obviousness over several prior art references.
The issue in the appeal was the Board’s findings concerning the combination of Young[1] and Gerber.[2]
Young describes a clinical study of patients who received percutaneous implantations of an electrical neurostimulator to treat chronic facial pain resulting from injury to the trigeminal nerve or nerve root. Gerber describes “an implantable medical lead having at least one electrode contact wherein the lead is implanted near the sacral nerves for stimulation” and a “method of implantation and anchoring of the medical lead near the sacral nerve.”
Axonics argued that a relevant artisan would have been motivated to combine the teachings of Young and Gerber because both address the similar problems of leads adequately stimulating the nerves while limiting electrode mitigation—a problem that Axonics contended the Medtronic patents also address. The prior art references and the Medtronic patents, according to Axonics, are also from the same field: “neurostimulation with implantable medical leads with electrode(s) at the distal end of the lead and a proximal anchoring mechanism.” Further, Axonics argued that Young expressly provides a motivation to make the asserted combination because it states that the neurostimulator used in the clinical study “could be improved to provide multiple active stimulation sites near the tip.” Axonics stated that Gerber “discloses multiple electrodes on implanted leads for sacral nerve stimulation” and an “anchoring means that fixes by fibrosis.” Axonics added that, at the priority date, there were a limited number of devices available to anchor by fibrosis, tines being the predominant one—the Medtronic patents claim a plurality of tine elements as the fixation mechanism of the medical lead.
The Board found that the proposed combination of prior art references discloses each limitation in the challenged claims; nevertheless, the Board rejected Axonics’ arguments that a relevant artisan would have had a motivation to combine Young with Gerber. First, the Board defined the relevant art as focused specifically on sacral-nerve stimulation by relying on the “Field of the Invention” section. Second, the Board found that Young, Gerber, and the challenged patents do not solve the same problem. The Board reasoned that the challenged patents and Gerber address sacral nerve stimulation while Young addresses trigeminal nerve stimulation. Third, the Board disagreed with Axonics that Young expressly provides a motivation to combine. The Board determined that Young’s sentence on improvement by adding electrodes would not have motivated a relevant artisan to combine Young’s lead with a plurality of electrodes distal to all of the tines (as taught in Gerber) because “such an arrangement would not be feasible in the trigeminal nerve region” given the tight tissue-related spacing constraints of that particular nerve region.
Vacating the final written decisions, the CAFC found that the Board committed two errors. First, the Board adopted a legally incorrect framing of the motivation-to-combine question when it confined the inquiry to whether a motivation would exist to make the Gerber-Young combination for use in the Young-specific trigeminal-nerve context—a context not required in the Medtronic patent claims. The CAFC stated that the proper inquiry is whether the relevant artisan would be motivated to make the combination to arrive at the claims’ actual limitations, which are not limited to the trigeminal-nerve context. Second, the Board erred in its definition of the relevant art as limited to medical leads for sacral-nerve stimulation. Because the claims make no reference to sacral anatomy or sacral neuromodulation, they cannot be properly construed as so limited.
[1] Ronald F. Young, M.D., Electrical Stimulation of the Trigeminal Nerve Root for the Treatment of Chronic Facial Pain, 83 Journal of Neurosurgery 72 (1995).
[2] U.S. Patent No. 6,055,456.
