How Enablement is Determined

By: David S. Forman


For a patent to be valid, the description of the invention in the patent must describe “the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same.”  35 U.S.C. § 112(a).  This is called “the enablement requirement.”  The enablement requirement must also be met for a patent application to have benefit of its filing date.

Storer v. Clark, 860 F.3d 1340 (Fed. Cir. June 21, 2017) provides a good example of how the enablement requirement can be analyzed to determine whether an application is entitled to its filing date.  The case was an interference, a contest in the USPTO to determine which of two parties was the first to invent a method of treating hepatitis C by administering a novel group of compounds.[1]  Although Storer had a patent application with an earlier filing date, the Patent Trial and Appeal Board found that its application did not enable the invention and awarded priority to Clark based on Clark’s later but fully enabled patent.  Storer appealed, and Federal Circuit again reviewed whether Storer’s patent application was enabled.

Enablement does not necessarily require a detailed recipe telling how to make and use the claimed invention.  The description in an application can be combined with what was known to those in the art at the time the application was filed, some trial and error may be needed to find the right combination.  Some experimentation is permitted, but if making the invention would have required “undue experimentation” (i.e. too much experimentation, an unreasonable amount of experimentation), then the application is not enabling.  In Storer v. Clark, the drug was a carbon ring to which various chemical groups were attached, and the groups had to be in the right orientation in relation to other groups (up or down).  Storer’s application described these compounds, but did not spell out how to make the drug with the groups in the right orientation.  So the question was whether a person in the art could have made these compounds based on what was in the Storer application and what was known to those in the art, allowing for some experimenting, or whether it would have required undue experimentation to make them.

Whether undue experimentation is required is not a simple determination; it is a conclusion reached by weighing many factual considerations.  The factors to consider were summarized in In re Wands, 858 F.2d 731  (Fed. Cir. 1988).  Factors to consider may “include (1) the quantity of experimentation necessary, (2) the amount of direction or guidance presented, (3) the presence or absence of working examples, (4) the nature of the invention, (5) the state of the prior art, (6) the relative skill of those in the art, (7) the predictability or unpredictability of the art, and (8) the breadth of the claims.”  Id. at 737.  Not all of these factors may be relevant in every case, and their weight can vary.

In Storer v. Clark the drug compounds of the invention have a fluorine atom attached at the 2 position of the carbon ring with a “down” position.  The parties agreed that the key question was whether the Storer application together with the prior art enabled making compounds having a 2´F(down) substituent.  The Board considered this question in light of all of the Wands factors and concluded that when the application was filed, making this type of compound was not enabled, and thus awarded priority to Clark.  On appeal, the Federal Circuit again looked at all of the Wands factors and reached the same conclusion.  While the details of these analyses involved some complicated organic chemistry, these decisions provide a clear example of how the Wands factors should be applied to determine whether making a compound requires undue experimentation.

When all of the factors were considered, one that counted heavily was (7), the predictability or unpredictability of the art.  Chemical reactions to make the target compounds were unpredictable.  The record showed many difficulties and failures of the inventors and others who tried to make the target compounds, contrary to Storer’s arguments that they could have been easily applied.  The Board concluded, and the Federal Circuit did not disagree, that at the time of filing “a high amount of experimentation is necessary to synthesize a 2´-fluoro-2´-methyl nucleoside with the fluoro moiety in the “down” position, requiring at least two years of a high priority experimentation by persons skilled in the art, including multiple consultations with experts at the top of the fields and additional formal training.”  (Emphasis added).  Thus, based on the entire record and the Wands factors analysis, this amount of experimentation was clearly undue, and therefore the Storer application was not enabled.  This case provides a textbook example of how enablement is analyzed.


[1]   Both patent applications were filed before the effective date of the America Invents Act, the statute that abolished the first-to-invent interference rule in favor of a first-to-file rule.