PTAB

IPR2020-00714

Axonics Modulation Technologies, Inc. v. Medtronic, Inc.

Title: Inductively Rechargeable External Energy Source, Charger, System and Method for a Transcutaneous Inductive Charger for an Implantable Medical Device
Brief Description: The ’324 patent discloses a system for transcutaneously recharging an implantable medical device. The system features an external charging device with a temperature sensor adapted to monitor the temperature of the housing’s patient-contacting surface, and a control circuit that regulates energy transfer based on the measured temperature to prevent overheating of patient tissue.

Prior Art Relied Upon: Torgerson (WO 01/83029) and UL 544 (a 1998 industry standard for medical equipment).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Torgerson disclosed a transcutaneous charging system for an implantable neurostimulator that regulated charging energy based on the temperature of the implanted device to ensure safety. However, Torgerson did not explicitly teach placing a temperature sensor on the external charger’s housing. UL 544 was a U.S. industry safety standard that mandated a temperature limit (41° C) for any part of a medical device applied to a patient.
- Motivation to Combine (for §103 grounds): A person of ordinary skill in the art (POSITA) would combine these references because compliance with the UL 544 safety standard was effectively mandatory for regulatory approval and commercialization. To ensure the external charger's patient-contacting surface did not exceed the mandated temperature limit, a POSITA would have found it obvious to add a temperature sensor to that surface for monitoring.
- Expectation of Success: A POSITA would have a reasonable expectation of success because Torgerson already taught the necessary control circuitry to regulate charging based on temperature feedback. Modifying this existing control system to accept an additional temperature input from an external sensor would be a predictable and straightforward implementation.

Prior Art Relied Upon: Torgerson (WO 01/83029), UL 544 (1998 standard), and Wang (Patent 5,702,431).
Core Argument for this Ground:
- Prior Art Mapping: This ground built upon Ground 1 to address claims reciting specific energy control methods. Petitioner asserted that Wang taught several well-known techniques for limiting temperature rise in transcutaneous charging systems, including controlling the duty cycle of energy transfer (e.g., via pulse-width modulation), switching the energy transfer on and off, and limiting the charging current.
- Motivation to Combine (for §103 grounds): A POSITA, having been motivated by Torgerson and UL 544 to control the external charger's surface temperature, would look to known solutions to implement that control. Petitioner argued that Wang provided a toolbox of such solutions, and it would have been obvious to apply Wang’s specific energy modulation techniques (e.g., duty cycle control) to the system of Torgerson to achieve the required temperature limitation.

Prior Art Relied Upon: Barreras (Patent 5,733,313) and Taylor (Patent 6,685,638).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner presented this as an alternative primary combination. Barreras was argued to teach a transcutaneous charging system with a temperature-controlled feedback loop, but its sensor was located on the implantable device, and it did not detail the external housing. Taylor was cited for disclosing an external transmitter with a specific housing design that included a thermistor on its patient-contacting feet to ensure the surface temperature complied with safety standards (EN60601, a European counterpart to UL 544).
- Motivation to Combine (for §103 grounds): A POSITA developing the charging system of Barreras would need to ensure its external transmitter was safe for patient contact to gain regulatory approval. Petitioner contended it would have been obvious to incorporate the external housing and patient-contacting temperature sensor taught by Taylor into the Barreras system to solve this problem.
Additional Grounds: Petitioner asserted additional obviousness challenges based on the Torgerson/UL 544 combination in further view of Mann (addressing claims for user status indicators and adjustable assemblies), and the Barreras/Taylor combination in further view of Wang (addressing claims for specific energy control methods) and Mann (for user status and adjustability).

"[a temperature sensor adapted to provide an output] indicative of a temperature of the side of the housing": Petitioner proposed this phrase be construed to mean "accurately measuring a temperature of the external surface portion of housing that is placed against the patient during recharging." This construction was argued to be supported by the specification’s emphasis on preventing tissue damage and was important for leveraging safety standards like UL 544, which require accurate temperature management.
"Adjustable assembly adapted to adjust efficiency of energy transfer...": For claim 5, Petitioner proposed this term be construed as "a component of the external device that is moveable relative another component of the external device to adjust efficiency of charging." This construction was used to map prior art disclosures of fine-tuning coil alignment onto this claim limitation.

Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate. It acknowledged that the primary prior art references (Torgerson, Barreras, Wang) were listed on an Information Disclosure Statement (IDS) during prosecution. However, Petitioner contended there was no evidence that the Examiner ever substantively considered these references or, critically, the specific combinations and arguments presented in the petition.

Petitioner requests institution of inter partes review (IPR) and cancellation of claims 1-24 of Patent 9,463,324 as unpatentable.