The U.S. Court of Appeals for the Federal Circuit (CAFC) recently affirmed the International Trade Commission's (ITC) decision in Celanese International Corp. v. ITC, ruling that Celanese's process claims were invalid due to secret sales of products made by the claimed process prior to the one-year on-sale bar, as codified in 35 U.S.C. § 102(a). This decision followed the Supreme Court's reasoning in Helsinn Healthcare v. Teva Pharmaceuticals (2019), rejecting Celanese's argument that the America Invents Act (AIA) altered the on-sale bar to exclude sales of products made by undisclosed processes.
The case arose from an ITC investigation into sweeteners imported by a Chinese manufacturer, which allegedly infringed Celanese's patents. It was undisputed that Celanese's process was used in Europe, resulting in sales by Celanese of the sweetener more than a year before the patents' effective filing date. The ITC found the process claims invalid, concluding that the AIA did not change the on-sale bar's interpretation.
On appeal, the Federal Circuit emphasized that the on-sale bar has been part of U.S. patent law since the Patent Act of 1836, consistently interpreted to include sales of products made by a secret process. The court cited prior cases where patent claims were invalidated due to the commercial exploitation of a process more than a year before filing for patent rights.
Celanese argued that AIA's change of wording in Section 102(a)(1) from "invention" to "claimed invention" and the addition of "otherwise available to the public" meant the process itself must be sold or publicly disclosed to invalidate the patent. The Federal Circuit rejected these arguments, noting that the changes were clerical and did not alter the established interpretation of the on-sale bar. Additionally, the one-year grace period for public disclosures in Section 102(b)(1) did not apply, as Celanese's sales occurred outside this window.
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