Staking your Claim: Defining and Enabling your Invention to get a Priority Date

March 2, 2021
By Ian McMillan, Cameron Gale and Christopher Kowal

You understand how your invention works. Now you want to stake your claim to the invention as broadly and inexpensively as possible. By filing a patent application that establishes your possession of the invention you can obtain a priority date for your invention. And you want to do so soon since, to obtain a valid patent, you must be the first to establish possession of the claimed invention (your application must have priority in time). Whether you have first possession of a claimed invention is judged as of the priority date, typically the filing date of your first patent application (to be patentable, your claimed invention must be new and unobvious as of the priority date). Delaying the priority date may make it impossible to establish first possession.

To establish possession, you must file in a patent office a written description of your invention that enables a person skilled in the art to make or use the invention (you must enable the invention). But this may not, on its own, establish possession since you must also precisely define the invention. This ensures that your patent can demarcate what is yours from what is not, to provide notice to others of the full scope of the patent rights claimed. And until you have defined your invention, you may not know whether you have properly enabled it. In either case, you may lose your priority date, potentially losing your patent rights.

Failing to define your invention

This problem can arise with provisional applications, or indeed in any rapidly or poorly drafted application, provisional or otherwise. While a provisional application must describe the invention, it need not include claims, unlike a non-provisional application. Claims are drafted to define the invention for which protection is sought, distinguishing it from the state-of-the-art. A provisional application expires on the first anniversary of its filing date, but within that period a regular application, which must include claims, can be filed claiming priority from the provisional application. Thus, you can defer drafting the claims for up to a year. Since claim drafting can be time-consuming and expensive, you may be tempted to defer or minimize this step, but this may endanger your priority date, and any patent rights eventually obtained.

If a provisional application provides an enabling description but fails to describe features required to distinguish the invention from the state-of-the-art, then any later filed patent application claiming priority to the provisional application, and any patent issuing on it, will not enjoy the provisional application’s filing date as a priority date, which may invalidate the patent or prevent you from obtaining a patent at all.

For example, an enabling disclosure may fail to sufficiently define the invention enabled where this invention incorporates hidden structure omitted from the enabling disclosure. This was the case in New Railhead Manufacturing LLC v. Vermeer Manufacturing Co. (298 F.3d 1290 (Fed. Cir. 2002) [New Railhead]) (more details available here) where an angled relationship of drill components, claimed to distinguish the patented horizontal drilling bit as new and unobvious over the prior art, was not explicitly disclosed in the provisional application. New Railhead argued that if the tool was made using the provisional application’s drawings, then the claimed relationship would be present as the drawings were accurate scale drawings. But the Court found that the disclosure’s adequacy is measured from the application itself, and that the disclosure requirement is not satisfied if one of ordinary skill in the art must first make the patented invention before the claimed features can be ascertained. Thus, the patent could not claim priority from the filing date of the priority application and was invalidated as anticipated.

New Railhead shows how providing an enabling disclosure of the invention may not establish possession of the invention if features required to distinguish the invention as new and unobvious are hidden, neither shown in the drawings nor explicitly disclosed in the enabling disclosure. To properly stake your claim to your invention, you must think about how to distinguish it as new and unobvious. This may rely on features of your invention that you would not need to think about to merely provide an enabling disclosure.

This problem, of failing to define the invention, can also arise in non-provisional patent applications. In Amgen v Sanofi, 872 F.3d 1367 [Amgen] (more details available here), the patents at issue included an enabling description for the claimed inventive antibodies by describing the structure of the new antigen to which the antibodies bind. However, the Federal Circuit held that the written description of the invention could not be found “merely from a finding of ability to make and use” the invention. An enabling description was not sufficient to precisely define the invention (the antibodies). Thus, the description failed to demonstrate possession of the claimed antibodies. This decision is a departure from previous US practice as well as the practice in other jurisdictions.

Enabling your invention as claimed (or defined)

Before drafting a patent application, you should be able to provide an enabling disclosure of some initial embodiments of the invention. However, once the invention has been defined in the claims, enablement should be revisited because the claims will cover not only these initial embodiments but also many other embodiments, not all of which can be explicitly mentioned in the specification. This may be particularly relevant for functionally claimed inventions.

For example, in Amgen Inc. et al. v. Sanofi, Aventisub LLC, et al., 20-1074 (Fed. Cir.) a later decision in the same Amgen litigation discussed above, the patents at issue defined the antibodies claimed in terms of their function of binding to a particular protein to reduce levels of LDL cholesterol. The specification described 26 such antibodies and how to screen to find more such antibodies, but the asserted claims covered many more antibodies not specifically disclosed. These claims were found to be far broader in functional diversity then the disclosed examples. Consequently, the specification did not, without undue experimentation, enable the full scope of these claims. The claims were thus invalidated for lack of enablement.

Takeaways for drafting patent applications

To demonstrate possession of your invention you must define it, distinguishing it from the prior art. While provisional applications need not include claims, a provisional application that fails to define the invention will not provide an effective priority date, even if it adequately describes how to implement some embodiments of the invention. Thus, any patent application, provisional or otherwise, must define the invention.

Only after the invention has been defined, typically after the claims have been drafted, you should consider whether the full scope of the defined invention has been adequately enabled. While you want to claim possession of as broad a conception of your invention as possible, after doing so you must ask yourself if the specification has enabled the full scope of this broad conception, or if, analogizing the scope of the claim to a plot of land, the specification has instead demonstrated possession only of a small corner of that plot of land.

By failing to account for these two aspects of possession, whether in a provisional or non-provisional application, you may surrender patent protection to which you would otherwise be entitled.

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