Panel: Judges Prost, Clevenger, and Dyk, with Judge Dyk writing the opinion You should read this case if: you have a prior art patent that was cancelled in inter partes review In our case of the week, a patent challenger challenged patent claims as obvious in light of a prior patent. But that prior patent was itself cancelled in an inter partes review. Does that patent remain prior art for purposes of the obviousness analysis? Baxter, the patent owner in this case, argued “no.” In Baxter’s view, an inter partes review is a second look at the patent grant, so when the inter partes review results in cancellation, it’s as if the patent was never granted in the first place.