Selling a product made using a secret process more than one year before the patent filing date would bar the patentability of that process. D.L. Auld Co. v. Chroma Graphics Corp., 714 F.2d 1144, 1147 (Fed. Cir. 1983) (explaining that on-sale bar precludes an inventor's attempt to profit from commercial exploitation of his invention for more than one year before seeking a patent); see also Medicines Co. v. Hospira, Inc., 827 F.3d 1363, 1371–73 (Fed. Cir. 2016) (en banc) (reviewing historical development of the on-sale bar); In re Kollar, 286 F.3d 1326, 1333 (Fed. Cir. 2002); In re Caveney, 761 F.2d 671, 675 (Fed. Cir. 1985); W.L. Gore & Assocs., Inc. v. Garlock, Inc., 721 F.2d 1540, 1550 (Fed. Cir. 1983); Metallizing Eng'g Co. v. Kenyon Bearing & Auto Parts Co., 153 F.2d 516, 520 (2d Cir. 1946) (observing that an inventor “shall not exploit his discovery competitively after it is ready for patenting; he must content himself with either secrecy, or legal monopoly”). An inventor's “voluntary act” of exploiting his invention through a commercial sale before the critical date constitutes “an abandonment of his right” to a patent. Pfaff v. Wells Elecs., Inc., 525 U.S. 55, 64 (1998). The “on-sale” bar does not require that a qualifying commercial sale reveal to the public the details of the claimed invention. Helsinn Healthcare S.A. v. Teva Pharms. USA, Inc., 586 U.S. 123, 130 (2019). 

The on-sale bar applies when a patentee sells, before the critical one-year date, products made using a secret process. 

Citing Helsinn, 586 U.S. at 130 (explaining that Congress reenacted the “on sale” language “against the backdrop of a substantial body of law interpreting § 102's on-sale bar”), the Federal Circuit recently affirmed in Celanese Intl. Corp. v. Intl. Trade Comm’n, No. 22-01827, __ F.4th __ (Fed. Cir. Aug. 12, 2024), that the AIA did not upset this long-settled precedent. 

Although the word “invention” was changed to “claimed invention” within Section 102(a)(1) under the AIA, the Federal Circuit identified this as “no more than a clerical refinement of terminology for the same meaning in substance.”  Indeed, pre-AIA precedent often used “claimed invention” interchangeably with “invention” in connection with the on-sale bar. The AIA had also added the “or otherwise available to the public” language to Section 102(a)(1); but, citing Helsinn, the Federal Circuit noted that this was “simply not enough of a change” to conclude that Congress intended to alter the settled meaning of “on sale.” 

Whatever the type of invention, the on-sale bar precludes one from commercially exploiting the invention and then continuing that exploitation through a patent, effectively extending the statutory patent term.

Here, it was "undisputed that Celanese's patented process was in secret use in Europe before the critical date of September 21, 2015, i.e., one year before the effective filing date of the asserted patents." Thus, Celanese's prior sales of its Ace-K sweetener made using its secret process, more than a year before the critical filing date, triggered the on-sale bar and invalidated its later-sought patent claims on that process.