A question that often comes up in patent drafting and counseling is whether an inventor has to prove an invention actually works in order to get a patent, either by actually making the thing or offering some other conclusive proof that the invention does what the inventor thinks it will do.
The answer is “No,” and a recent decision by the Federal Circuit Court of Appeals reiterates this precedent.
To understand this concept, lets discuss what an invention is. The courts have long held that conception is the key part of an invention. “Conception is the touchstone of inventorship.” Ethicon, Inc. v. United States Surgical Corp., 135 F. 3d 1456, 1460 (Fed. Cir. 1998), citing Burroughs Wellcome Co. v. Barr Laboratories, Inc., 40 F. 3d 1223, 1227-1228 (Fed. Cir. 1994). The test for conception is whether the inventor had an idea that was definite and permanent enough that one skilled in the art could understand the invention. Burroughs Wellcome at 1228. If there is a question of when or what the conception is, the inventor must prove his conception by corroborating evidence (id.) – but the inventor need not actually make the thing, which is called reduction to practice.
Reduction to practice is optional: an inventor need not know that his invention will work for conception to be complete (id.). An inventor need only show that he or she had the idea; the proof that an invention is reduced to practice (i.e., actually works) is not required to prove the date or content of the invention (id.).
This issue came up in a recent Federal Circuit decision, in Medtronic, Inc. v. Teleflex Life Sci. Ltd., No. 22-1721 (Fed. Cir. 11/16/2023). One of the issues in this case was that the patent challenger (Medtronic) sought to use a prior art reference, the “Itou” patent, to prove obviousness. The Itou patent had a priority date of September 23, 2005, but the Teleflex invention had a priority date of May 3, 2006. That is, Itou was prior art under 35 USC §102(e) (pre-AIA law) unless Teleflex could antedate it, meaning that Teleflex had to show a date of conception prior to the Itou priority date. This was a feature of pre-AIA law. Under the current law, it is not possible to antedate such a reference. But this case is still instructive for the issue that reduction to practice is not necessary to prove an invention under the current (AIA) law.
The rule in antedating a §102(e) reference is that the inventor(s) have to show a date of conception of the claimed invention prior to the critical date (here, that is the priority date of Itou) and either actual reduction to practice prior to the reference’s critical date or constructive reduction to practice with “reasonably continuous diligence” in reducing the invention to practice, that is, working on the project, until its effective filing date.
The Patent Trial and Appeal Board (PTAB) heard several Inter Partes Review (IPR) cases related to this technology and found that the invention was conceived and reduced to practice prior to the Itou filing date. This holding was upheld by the Federal Circuit.
But Medtronic argued at the PTAB, and on appeal, that there was no reduction to practice because Teleflex did not perform in vivo testing. The inventions in this case pertained to cardiac stents and catheters for placing such stents. In vivo testing would have meant essentially that the invention was tested in animals or on actual patients.
The PTAB rejected the argument that in vivo testing was required to prove reduction to practice. Medtronic “was unable to identify any legal precedent requiring in vivo performance of a claimed in vivo method to show actual reduction to practice.” Teleflex said they made a physical model that replicated the anatomy in which the method would be used, and the PTAB and Federal Circuit believed this was good enough.
In other words, in vivo testing, or use in actual patients, was not required to prove the date or scope of the invention. Here, the inventors made a model to show the device would work, but the standard here was higher than normal, because Teleflex had to antedate a §102(e) reference. In most cases, a model or any other proof is not required (see cites to Burroughs Wellcome above), as long as the inventors and patent drafter can show that the invention makes sense to a person of ordinary skill in the art.
Under current AIA law, as in most countries, we no longer care when an invention was made. The AIA law is that the first inventor to file a patent application has seniority. So the key now is getting a filing date, and the current law incentivizes early filing. In many cases, this may be prior to lab work demonstrating that the invention works or is operable. Such early filings are perfectly acceptable as long the invention makes sense to a person of ordinary skill in the art. Generally, early filing should be accomplished with provisional patent applications.
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Andrew Berks, Ph.D., J.D.
March 19, 2024
