Generic Examples of Claimed Compounds Do Not Satisfy Enablement Requirement

Federal CircuitStorer v. Clark, No. 2015-1802, 2017 (Fed. Cir. June 21, 2017) (Before Prost, C.J., Newman, and Dyk, J.) (Opinion for the court, Newman, J.).

On June 21, 2017, the Federal Circuit affirmed a Patent Trial and Appeal Board’s interference decision, which awarded priority to Clark’s pending application (filed May 30, 2003) over Storer’s issued patent. The Court found that Storer’s earlier provisional application (filed June 28, 2002) did not enable the subject matter of Storer’s interfering claims.

Storer and Clark both claimed a method of treating hepatitis C using modified nucleoside compounds, including heterocyclic compounds having a fluorine substituent in the 2? (down) position. Clark filed a motion to deny Storer the benefit of its provisional application and to invalidate Storer’s priority claims based on lack of enablement. The PTAB held that Storer’s provisional application, together with the prior art, did not enable the specific compound claimed, and it awarded priority to Clark. Storer appealed. The only question on appeal was whether Storer’s provisional application enabled compounds having a fluorine substituent in the 2? (down) position.

When a party to an interference seeks to benefit from the filing date of an earlier application, the earlier application must meet the requirements of 35 U.S.C. § 120 and the written description, enablement, and best mode requirements of 35 U.S.C. § 112 ¶ 1. To establish enablement of a claim that uses new chemical compounds to treat disease, the application must enable production or synthesis of the new compounds. The enablement requirement is met when one skilled in the art, having read the specification, can practice the invention without “undue experimentation.”

The Court found there was substantial evidence to support the Board’s findings that a person of ordinary skill in the art, using the disclosure in the provisional application and the knowledge of the prior art, would not have been able to make a compound with the claimed fluorine substituent in the 2′ (down) position without undue experimentation. The Storer provisional disclosed two general approaches to synthesis but did not describe synthesis of the target compound. Storer did not identify any specific compound having the claimed 2′ (down) structure, instead disclosing only generic structures and generic formulas for the claimed compound. The Court noted that Storer and his team were unable to synthesize the target compound even after filing the provisional application and that the experts in the field were skeptical of Storer’s invention.

Storer argued that the prior art contained a “well-known precursor compound that is only one step away from the target compound” and that the precursor, together with the Storer provisional, enabled synthesis of the claimed compound. However, the Storer provisional did not mention the precursor and did not show how to convert the precursor to the claimed structure. Viewing all the evidence, the Court agreed with the Board that the provisional application did not teach or suggest conversion of any precursor into the claimed structure and that the precursor did not enable one of skill in the art to produce the claimed compound without undue experimentation.

To satisfy the enablement requirement, applicants should provide either explicit examples of claimed compounds or direction or guidance on how to synthesize the claimed compounds. Disclosing generic structures or general approaches to synthesis does not by itself satisfy the enablement requirement for specific compounds. A known precursor does not enable synthesis of a claimed compound if the application does not disclose the precursor or how to convert it into to a claimed compound.

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One comment so far.

  • [Avatar for Paul Cole]
    Paul Cole
    July 2, 2017 01:28 pm

    An opinion of Judge Pauline Newman about an invention in the chemical arts. Enough said!

    A useful reference for future cases.

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