IP Law Daily PTAB decisions invalidating claims for microscope slide stainers affirmed
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Friday, December 2, 2016

PTAB decisions invalidating claims for microscope slide stainers affirmed

By Thomas Long, J.D.

The Patent Trial and Appeal Board correctly determined that claims in two patents for microscope slide staining devices were invalid in light of prior art, the U.S. Court of Appeals for the Federal Circuit has held. In two inter partes reexaminations, Leica Biosystems Melbourne Party Ltd. challenged claims of U.S. Patent No. 7,217,392 ("the ’392 patent") and a continuation of that patent, U.S. Patent No. 7,553,672 ("the ’672 patent"), both held by Dako Denmark A/S. The Board determined that the claims of the ’392 patent were invalid as obvious and that the claims of the ’672 patent were invalid as anticipated and obvious. On appeal, Dako contended that the Board erred in invalidating claim 7 of the ’392 patent and claim 2 of the ’672 patent. The Federal Circuit affirmed (Dako Denmark A/S v. Leica Biosystems Melbourne Party Ltd., December 2, 2016, Prost, S.).

The ’392 patent. The ’392 patent related to slide staining devices for the application and removal of reagents to biologic tissue sections mounted on microscope slides. Slide staining is used to aid in the microscopic examination of tissue samples. The invention of the ’392 patent addressed the need for a slide stainer that can apply different processes to a single slide, and that can simultaneously process multiple slides in different ways. Different staining techniques potentially require that slides be heated at different temperatures and for different times; the ’392 patent disclosed slide staining methods and systems that allowed for heating of each slide to its own specified temperature. To facilitate individualized control, the patent described a system containing multiple "slide frames" in which each slide frame contained a separate heating element.

Key to the obviousness analysis was a term in claim 7—"a heating element that underlies only one microscope slide." The Board determined that one prior art reference, "Tseung," disclosed every claim limitation except the requirement that each heating element underlie only one slide. This limitation was found in another reference, "Muller," which disclosed individual heating elements for each slide. The court agreed with the Board that Muller’s teachings were "directly pertinent to Tseung," and that a skilled artisan would be motivated to combine the teachings. The Federal Circuit held that the Board had substantial evidence to support its factual finding of the motivation to combine. Because Tseung taught a system that was "readily programmable to allow automated staining of individual microscope slides with different techniques without operator intervention in a single operation," its later discussion as to the benefits of heating slides would reasonably motivate a person of ordinary skill to look for a way to adapt the system to heat individual slides to different temperatures, the court said.

Dako did not contest the Board’s finding that, together, Tseung and Muller disclosed every element of claim 7. Dako did argue, however, that the Board failed to give proper consideration to evidence of secondary considerations that, according to Dako, demonstrated non-obviousness. In particular, Dako presented an expert witness’s declaration that a competitor, Ventana, had copied the invention of the ’392 patent. In the court’s view, the Board gave proper consideration to this evidence before deciding that the declaration did not support a contention that the alleged Ventana product had actually been made and marketed. In addition, the court affirmed the Board’s conclusion that, even if copying had been established, that factor would not outweigh the other evidence of obviousness.

The ’672 patent. Claim 2 of the ’672 patent described a method of processing samples mounted on microscope slides. The Board decided that this claim was invalid as anticipated by Tseung. Dako’s only argument on appeal was that the Board improperly construed the claim term "slide support." The Board rejected Dako’s argument that the term should be construed as "a heating element that underlies the only one microscope slide and has a surface on which the only one microscope slide rests so as to transfer heat to the at least one microscope slide." In the Board’s view, the heating element described in claim 1 supported "at least one" microscope slide, which indicates that it may support multiple slides. The Board further determined that there was no limitation in claim 2 that narrowed this capability. The Board found additional support for its interpretation from the ’392 patent, which expressly disclosed a system in which a heating element underlies only one slide. Based on this construction, the Board determined that Tseung met all the limitations of claim 2 and thus anticipated it. The Federal Circuit agreed with the Board’s construction. Nothing in claim 1 or 2 supported Dako’s contention that claim 2 required individual slide supports to be capable of individual temperature control. Because Dako challenged only the claim construction, and did not argue that Tseung failed to anticipate claim 2 under this construction, claim 2 of the ’672 patent was invalid, the court concluded.

The case is Nos. 2015-1997 and 2016-1000.

Attorneys: John M. Griem, Jr. (Carter Ledyard & Milburn LLP) for Dako Denmark A/S. David G. Mangum (Parsons Behle & Lati) for Leica Biosystems Melbourne Party Ltd.

Companies: Dako Denmark A/S; Leica Biosystems Melbourne Party Ltd.

MainStory: TopStory Patent FedCirNews

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