In re Ruschig
379 F.2d 990 (1967)
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Rule of Law:
To satisfy the written description requirement of 35 U.S.C. § 112, a patent application's specification must do more than merely render a claimed chemical compound obvious or enable its creation; it must convey to one skilled in the art that the applicant had possession of and actually invented the specific compound being claimed.
Facts:
- Appellants Ruschig et al. filed a patent application for a new class of chemical compounds, 'New Benzene Sulfonyl Ureas,' and a process for making them.
- The application disclosed a broad genus of compounds, potentially encompassing over half a million different molecular structures, defined by a general formula with several variable components.
- The specific compound N-(p-chlorobenzenesulfonyl)-N'-propylurea, later known as chlorpropamide, was not explicitly named or identified by its specific chemical formula within the application's text.
- The application disclosed a list of at least 19 possible primary amine reactants that could be used in the synthesis, including n-propylamine, but did not single it out or give it preference over the others.
- The application provided specific examples of twelve compounds from the broad class, but chlorpropamide was not among them.
- One of the specific examples provided, N-(4-chlorobenzenesulfonyl)-N'-n-butyl urea, was a close chemical homolog of chlorpropamide, differing only by the use of n-butylamine instead of n-propylamine in its synthesis.
Procedural Posture:
- Ruschig et al. filed patent application serial No. 601,107 with the U.S. Patent Office.
- The examiner suggested claim 13 to Ruschig for an interference proceeding against a Pfizer application.
- An interference was declared, during which Pfizer moved to dissolve on the ground that Ruschig's disclosure did not support the claim; the examiner denied the motion.
- The examiner later dissolved the interference, rejecting the claim as unpatentable over prior art.
- Ruschig appealed the prior art rejection to the Patent Office Board of Appeals, which affirmed.
- Ruschig then appealed to the Court of Customs and Patent Appeals, which reversed the Board's prior art rejection and remanded the case.
- On remand, the examiner reopened prosecution and issued a new rejection of claim 13, this time for lack of support in the written description.
- Ruschig appealed this new rejection to the Patent Office Board of Appeals, which affirmed the examiner's rejection.
- Ruschig (appellant) now appeals the Board's decision on the lack of support to the Court of Customs and Patent Appeals.
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Issue:
Does a patent application's disclosure of a broad genus of chemical compounds, without specifically naming or providing the formula for a particular species, satisfy the written description requirement of 35 U.S.C. § 112 for a claim to that specific species?
Opinions:
Majority - Rich, Judge
No. A patent application's disclosure of a broad genus of chemical compounds does not satisfy the written description requirement for a specific species within that genus if it does not convey to one skilled in the art that the inventors had possession of that specific invention at the time of filing. The fundamental question is not whether the disclosure enables one to make the compound, but whether the specification describes the compound as something the applicants actually invented. The application here describes a vast field of possibilities—a 'large number of unmarked trees'—without providing any 'blaze marks' or guidance to single out the particular compound of chlorpropamide from the myriads of other possibilities. Disclosing a close homolog gets 'close,' but it is not a description of the claimed invention itself. Hindsight cannot be used to find a path to the compound; the specification must, on its own, direct a person of ordinary skill in the art to the specific invention.
Analysis:
This case is a landmark decision that clarifies the written description requirement under 35 U.S.C. § 112 as a separate and distinct requirement from enablement. It establishes the 'possession' test, which requires that an inventor's disclosure demonstrate they were in possession of the specific claimed invention at the time of filing. This holding prevents applicants from claiming a broad field of research and later claiming a specific, valuable embodiment discovered after the fact, either by themselves or others. The decision has had a profound impact on patent prosecution, particularly in the chemical and biotechnology fields, where it requires greater specificity in disclosing and claiming individual compounds or gene sequences rather than relying on broad generic formulas.
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