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Federal Circuit Affirms PTAB On Motivation To Combine And Reasonable Expectation Of Success
10/11/2023On September 21, 2023, the United States Court of Appeals for the Federal Circuit affirmed a decision by the United States Patent and Trademark Office, Patent Trial and Appeal Board (“PTAB”), holding that claims of U.S. Patent No. 7,295,648 (the “’648 patent”) owned by Elekta Limited (“Elekta”) were unpatentable as obvious. Elekta Ltd. v. ZAP Surgical Sys., Inc., No. 2021-1985 (Fed. Cir. Sept. 21, 2023). The CAFC panel (Reyna, Stoll and Stark) reviewed the PTAB’s legal conclusions de novo and its factual findings for substantial evidence. In affirming the PTAB, the CAFC concluded that the PTAB’s factual findings as to both the motivation to combine prior art references and the reasonable expectation of success in making the combination were supported by substantial evidence.
The ’648 patent relates to a device for treating patients with ionizing radiation. It discloses using a radiation source, such as a linear accelerator (“linac”), mounted on concentric rings that rotate around a patient to deliver targeted radiation treatment. ZAP Surgical Systems (“ZAP”) challenged claims of the ’648 patent as obvious over a combination of prior art references, including Grady, Ruchala, and Winter. Grady discloses an x-ray tube mounted on rotating supports, including rings that rotate around the patient. Ruchala discloses a linac-based radiation therapy device integrated with CT imaging for treatment verification. Winter (relied on for background) discloses a combination of a CT scanner for imaging with the therapeutic irradiating of a target, which allows more accurate positioning by having a single device for both imaging and therapy.
ZAP argued that Grady could be combined with Ruchala by replacing the x-ray tube of Grady with the linac of Ruchala. At the PTAB, Elekta argued that a skilled artisan would not have been motivated to combine Grady, which discloses an X-ray imaging device, with Ruchala, which discloses a radiation therapy device. Elekta also argued there was no reasonable expectation of success.
On appeal, Elekta argued that: (1) the motivation to combine findings was unsupported by substantial evidence; (2) the Board failed to make any findings on the reasonable expectation of success; (3) even if the Board had found reasonable expectations of success, it was unsupported by substantial evidence; and (4) Zap had not met its burden to show a reasonable expectation of success by clear and convincing evidence.
The CAFC first disagreed with Elekta’s first argument, finding substantial evidence supported the PTAB’s determination that a skilled artisan would have been motivated to combine the references, including the prosecution history, the references themselves and expert testimony. The CAFC specifically noted that, in the prosecution of the ’648 patent, the patentee did not argue that imaging devices were not relevant art, undercutting its argument that there was no motivation to combine imaging device references with radiation treatment. Although prior art stating a motivation is not required, the PTAB noted that Ruchala teaches combining imaging with delivery of radiation and that Winter highlights the advantage of combining imaging and therapy devices.
The CAFC next considered Elekta’s challenge to whether the PTAB made sufficient findings on a reasonable expectation of success. The CAFC held that, while an explicit analysis is required for demonstrating a motivation to combine, a finding on reasonable expectation of success can be implicit. Here, by addressing Elekta’s arguments about operability and viability (which are intertwined with expectation of success), the PTAB had implicitly found a reasonable expectation of success.
The CAFC also held that sometimes, but not always, “the evidence establishing a motivation to combine may establish a finding or reasonable expectation of success.” Determining that to be the case here, the CAFC held that the PTAB’s expectation of success finding was also supported by substantial evidence.
Last, the CAFC rejected Elekta’s argument that ZAP had to prove reasonable expectation of success by clear and convincing evidence, clarifying that the standard is a preponderance of evidence in IPRs.
