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Federal Court Decision Has Implications for Patent Drafting
In a recent decision with implications for patent drafting, the Federal Court of Canada determined that a patent claim can be invalid if the written description insufficiently defines terminology found in the claim. The patent in this case related to a drug formulation with improved stability. The patent claimed an “anhydrous” composition (literally, “without water”). To a chemist, this term can have different meanings, depending on the context. The court looked to the specification for the meaning of "anhydrous". The specification defined this word functionally, in terms of a composition having insufficient free water to cause degradation. This was considered to be an expression of a desired result, rather than providing the means to reach that result, such as a specific limit on the amount of free water. The court then applied the same broad meaning of the term to the claim. Since the meaning of this term went to the core of the invention, the claim was invalid for being overly broad.
In some cases, it is permissible to define an invention, at least in part, in terms of a desired result. However, the patent must provide sufficient information to permit the skilled person to directly arrive at the desired result. The Court cited Justice Binnie of the Supreme Court of Canada in Free World Trust: “It is not legitimate… to obtain a patent for a particular method that grows hair on bald men and thereafter claim that anything that grows hair on bald men infringes."
This case emphasises the importance of carefully reviewing the specification and claims of a patent, to ensure that there is adequate definition of critical terminology.
The decision is available at: