by Dennis Crouch
If you break it down far enough, every invention is simply a combination of known materials or steps. In that frame, the obviousness inquiry fundamentally becomes a question of whether the combination of known elements was within the toolkit of an ordinary artisan. This is a flexible analysis (KSR) with the PTO and courts typically looking for a “motivation to combine” the prior art teachings that would have a “reasonable expectation of success.”
The Federal Circuit’s recent decision in Axonics, Inc. v. Medtronic, Inc., No. 2022-1451 (Fed. Cir. July 10, 2023) zeroes in on the motivation-to-combine analysis. In Axonics, the court ruled that the obviousness analysis must focus on the motivation to combine references to reach the claimed invention, not motivation to combine for some other purpose described in the prior art. The basic outcome is that it will prevent overly narrow framing of the motivation inquiry by the PTAB.
Medtronic has two patents that cover medical leads for nerve stimulation. Importantly for the case, although the claims appear broad enough to cover trigeminal nerve stimulation, they are not limited to that type of stimulation. Axonics IPR challenged the claims as obvious based upon two key prior art references: Young and Gerber. The Young patent relates to a lead for stimulating the trigeminal nerve, while the Gerber patent relates to a lead with a plurality of electrodes. Together, the two references taught all of the limitations found in the Medtronic claims. However, the PTAB concluded that an artisan would not have been motivated to combine the references. The PTAB started with Young’s focus on the trigeminal nerve stimulator, and found that the proposed addition of Gerber would fail to work for trigeminal nerve stimulation based on the anatomy of that area.
On appeal, the Federal Circuit found that the PTAB improperly limited the Young-Gerber combination analysis to what would work in the trigeminal-nerve area, which is a requirement of the Medtronic patents’ claims. The proper inquiry should have been 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. The Federal Circuit also found that the PTAB erred in its definition of “the relevant art” as limited to medical leads for sacral-nerve stimulation, as the Medtronic patent claims make no reference to sacral anatomy or sacral neuromodulation, and they cannot be properly construed as so limited.
This holding indicates that the PTAB cannot improperly narrow its view of the relevant art based on specification details not reflected in the claims. Rather, the relevant art must align with the scope of the claimed invention. The decision also underscores that the motivation analysis must focus on combining prior art to reach the claimed invention, not suitability for a specific context described in one reference.
I’ll note here that Judge Taranto justifies the decision with a statement about how the patent is not directed to sacral nerfes:
No claim of the two patents either mentions or is limited to sacral nerves. The same is true of the titles of the two patents.
I’ll note here that the rest of the patent is ripe with a focus on sacral nerves. As an example, the following comes from the background section:
This invention relates generally to a method and apparatus that allows for stimulation of body tissue, particularly sacral nerves. More specifically, this invention relates to an implantable medical electrical lead having at least one stimulation electrode adapted to be implanted near the sacral nerves for stimulation of a bundle of sacral nerve fibers and a fixation mechanism for providing chronic stability of the stimulation electrode and lead. Moreover, this invention relates to the method of implantation and anchoring of the medical electrical lead electrodes in operative relation to a selected sacral nerve to allow for stimulation.
Id.
On remand, the Board will need to take a fresh look at the Young-Gerber combination. But, it isn’t clear that the result will be obviousness since we still need to know whether someone of skill in the art would have some reason to believe they could to take the trigeminal nerve stimulator disclosed in Young; and combine it with plurality of electrodes disclosed in Gerber to make a non-trigeminal version covered by the claims.
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What is the invention? Traditionally, an invention requires reduction to practice; an actual embodiment. And, although we have long permitted patent filings as an alternative, the law sees that as merely a constructive stand-in for the real thing. At the same time, we have all heard the patent law maxim that an invention is defined be the scope of the claims. And, in 2011 the patent laws were finally amended to reflect that paper-focused framework by focusing attention on “the claimed invention” rather than just “the invention.” The amended law now requires an analysis of the “the differences between the claimed invention and the prior art” and whether “the claimed invention as a whole would have been obvious.” This was a subtle change, but one that fundamentally shifted focus from the historic framework of an invention that required reduction to practice toward the paper version that defines the invention in terms of what is claimed.
The difficulty for Medtronic in this case is that they took the original invention that focused on sacral nerves and decided to expand out the scope beyond that reach. (The company holds other patents in the family that do focus on sacral nerve stimulation).