PTAB Delivers Mixed Bag Decision for Medtronic and Axonics in Ongoing Patent Feud

Even patent judges sometimes make mistakes. That is the oversimplified takeaway from a patent dispute between Axonics and Medtronic that has been anything but simple.

The two companies have been locked in a fierce patent feud for more than 5 years now. At issue are certain Medtronic patents related to sacral neuromodulation for treating various bladder and bowel conditions. Medtronic sued Axonics for patent infringement, and Axonics responded by challenging the validity of multiple Medtronic patents.

In September 2021, the Patent Trial and Appeal Board (PTAB) upheld all the claims in Medtronic’s U.S. Patent Nos. 8,036,756 (‘756 patent) and 8,626,314 (‘314 patent). The PTAB also upheld one challenged claim in U.S. Patent No. 7,774,069 ('069 patent), which protects technology related to its recharge power control, but invalidated four claims in the ‘069 patent.

Axonics appealed to the U.S. Court of Appeals for the Federal Circuit. In August 2023, the Federal Circuit ruled that the PTAB had “erred in its obviousness analysis,” forcing the board to reconsider its decisions on the validity of the Medtronic patents.

So, the million-dollar question for the past several months has been, would the PTAB correct itself in favor of the Federal Circuit view, or would it double down on its earlier decision? The answer, it turns out, is a little bit of both.

Related:Medtronic Punches Down

In a written decision issued Thursday, the PTAB invalidated 10 of the 15 claims of Medtronic’s patent 8,626,314 which protects technology related to its tined leads. The board upheld the validity of the remaining claims in question. Medtronic previously told MD+DI that the '324 patent protects key technology related to implant recharging and temperature control and is central to the infringement case pending against Axonics. The ‘314 patent expired Feb. 18, 2022.

In a separate written decision, also issued Thursday, the PTAB again upheld the validity of all challenged claims in Medtronic’s patent 8,036,756. The ‘756 patent expired Nov. 9, 2021.

For a deeper dive into the more technical aspects of these patent reviews, scroll down.

Medtronic moves for patent litigation to continue

Medtronic will now ask the federal court in the Central District of California, where Medtronic's patent infringement lawsuit against Axonics is pending, to lift its stay on the lawsuit and proceed to trial on the patents that have been upheld so Medtronic can present its case in front of a jury.

Related:Axonics R20 Rechargeable Sacral Neuromodulation System Nabs CE Mark

“We respect the intellectual property of innovators, and our patent system exists to benefit society by encouraging the kind of innovation that Medtronic invests in. We are pleased with the PTAB's decision, and we are confident that the evidence at trial will show that Axonics improperly used and profited from Medtronic's patented technology.”

Medtronic InterStim Micro System with Recharger and Smart Programmer. IMAGE COURTESY OF MEDTRONIC

Separately, Medtronic recently filed a complaint with the U.S. International Trade Commission (ITC) along with a parallel lawsuit against Axonics in the U.S. District Court for the District of Delaware. In doing so, Medtronic is trying to block Axonics from importing and selling products that, according to Medtronic, infringe two additional patents related to the MRI compatibility of implantable medical devices.

Axonics to 'seek review' of upheld claims

Axonics recently secured a CE mark to sell its fourth-generation rechargeable sacral neuromodulation system in the EU. IMAGE COURTESY OF AXONICS

“We are pleased with the PTAB’s decision finding numerous claims of the ‘314 patent unpatentable,” said Axonics CEO Raymond Cohen. “Axonics will continue to vigorously defend itself against Medtronic’s claims while we remain focused on fulfilling our mission of changing the lives of patients suffering from bladder and bowel dysfunction.”

Related:Medtronic Won't Back Down but Axonics Stands Its Ground

As for the claims the PTAB upheld, Axonics plans to seek a review of those findings.

How will this impact Boston Scientific's pending acquisition of Axonics?

The ongoing patent feud between Medtronic and Axonics took an interesting turn in January when Boston Scientific announced plans to acquire Axonics in a $3.7 billion deal on track to close in the first half of the year. Until the transaction is finalized, Boston Scientific and Axonics continue to operate as separate and independent companies.

“Therefore, we do not have a comment regarding this litigation,” a Boston Scientific spokesperson told MD+DI.

A closer look at the technicalities

The Medtronic patents ‘314 and ‘756 describe and claim a neurostimulation lead and a method for implanting and anchoring the lead. According to the U.S. Court of Appeals for the Federal Circuit, the ‘314 patent is a grandchild of the ‘756 patent.

The “field of the invention” section of the ‘314 specification states that the invention relates generally to a method and apparatus that allows for stimulation of body tissue, particularly sacral nerves. More specifically, the 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, according to the Federal Circuit, the 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.

In its petition concerning Medtronic’s ‘314 patent, Axonics argued, among other things, that the challenged claims of the patent are unpatentable for obviousness over Young (Ronald F. Young, MD, “Electrical Stimulation of the Trigeminal Nerve Root for the Treatment of Chronic Facial Pain,” Journal of Neurosurgery, 1995).

Axonics specifically argued that a relevant artisan would have been motivated “to replace the one electrode of Young with multiple electrodes at the distal end distal to the anchoring mechanism, as taught by Martin Gerber, to provide more flexibility in activation of a wider area and provide the possibility for bipolar electrical stimulation, as taught in Young.

Combining the teachings of Young and Gerber

In its appeal, only the PTAB’s findings about the combination of Young and Gerber were presented for review. 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. The study was done to extend the application of electrical stimulation, which had already proven successful with spinal cord and deep brain stimulation, to the trigeminal system and chronic facial pain. The implanted neurostimulator used in the study consisted of a monopolar lead with two sets of four “tines” located a short distance proximal to the single electrode at the distal tip of the lead. The tines, according to Young, prevented the electrode from becoming dislodged after implantation. Young noted that the device could be improved by adding multiple active stimulation sites for greater flexibility in activation of a wider area of the trigeminal nerve root and would provide the possibility for bipolar electrical stimulation.

Gerber describes “an implantable medical lead having at least one electrode contact wherein the lead is implanted near the sacral nerves for stimulation.” Gerber also describes a method of implantation and anchoring of the medical lead near the sacral nerve. Gerber also disclosed that existing leads (at the time) for sacral nerve stimulation had four small discrete electrodes built into the distal end of the lead. Gerber’s implantable lead includes a distal end and a proximal end and may include an “anchoring mechanism” to keep the lead near the targeted sacral nerve.

So, Axonics argued, a relevant artisan (legalese for a person of ordinary skill in the art) would have been motivated to combine the teachings of Young and Gerber that solve the same problem as the ‘314 patent in the same field. Not to mention, Young expressly provided motivation to make the asserted combination. As for the anchoring mechanism that Gerber described, Axonics said in its appeal that there are currently a limited number of devices available to anchor by fibrosis, and tines are the predominant one.

What the PTAB got wrong

The board originally began by defining the relevant art and a relevant artisan, in agreement with Medtronic on the point of relevance here, as focused on sacral-nerve stimulation specifically. The board found that the relevant art is medical leads specifically for sacral neuromodulation, relying on the “field of the invention” statements to narrow the field in that way even though the claims are not limited to sacral nerves, according to the Federal Circuit. The board then concluded that a relevant artisan in this case is someone with at least two years of experience researching and developing medical leads for sacral neuromodulation.

The Patent Trial and Appeal Board then addressed the obviousness argument made by Axonics.

“The board agreed with Axonics that it had ‘demonstrated each limitation of independent claim 1 in its proposed combination’ including, as relevant here, a plurality of electrodes distal to all tines,” the Federal Circuit judge wrote. “Nevertheless, the board found that Axonics had not demonstrated that a relevant artisan would have had a motivation to combine Young’s lead with Gerber’s plurality of electrodes, so the plurality of electrodes is distal to all the lead’s tines. And this is why the PTAB initially rejected Axonics’ challenges. The board also noted that Axonics relied on the same reasoning for combining the teachings of Young and Gerber for all three independent claims. Medtronic and its expert countered that Young did not suggest to a relevant artisan to include a plurality of electrodes distal to all of the tines in the Young neurostimulator “because such an arrangement would not be feasible in the complex anatomy of the trigeminal nerve region.” The board agreed with Medtronic.

According to the Federal Circuit's remand, even if the board was correct to treat the Medtronic patents at issue as limited in the problem they address to the sacral-nerve context, the PTAB still messed up:

The court also found that the patent board was incorrect in its view that ‘the relevant art is medical leads specifically for sacral neuromodulation, because the Medtronic patent claims “are not limited to the sacral-nerve context and the shared specification, properly read, is not so limited either.”