French Cour De Cassation Clarifies Requirement Of Plausibility

Author:Mr Thomas Bouvet, Laura Romestant, Alastair J. McCulloch and Christian Paul
Profession:Jones Day

In Short

The Decision: The French Cour de cassation, in a case concerning a dosage regime patent, recently clarified the "plausibility" requirement, an element of sufficiency of disclosure or inventive step.

The Result: The wording of the Cour de cassation's decision creates a stringent plausibility requirement, but this decision was issued in relation to a patent claiming a specific administration mode and dosage, and a far less stringent plausibility requirement has been applied by lower courts in matters regarding other types of claims, in particular pure product or compound claims with no functional features.

The Requirement of Plausibility

The requirement for plausibility is not based in legislation, yet in Europe, a body of case law has created this requirement to distinguish those applications that actually do demonstrate a technical effect from purely speculative patents. The plausibility of the technical effect as set out in the patent also affects the patentee's ability to rely on experimental results available only after the filing date, for proving that a technical problem has indeed been solved.

The emergence of the concept of plausibility in relation to each of inventive step, sufficiency, and industrial applicability is now often invoked in the life sciences sector, where claimed technical effects are often not self-evident. In France, the requirement of plausibility has been examined under both sufficiency and inventive step.

The Plausibility Requirement Assessed by French Courts

In its decision of December 6, 2017, the Cour de cassation, France's highest civil court, clarified the outlines of the plausibility requirement when applied to second medical use claims and, more particularly, to dosage claims. This decision was rendered against a decision of the Court of Appeal of Paris of January 30, 2015, which held that European Patent No. 0 724 444 was invalid for insufficiency.

The European Patent at stake, "Method of treating androgenic alopecia with 5-alpha reductase inhibitors," comprised three claims directed to low-dosage oral administration of finasteride to treat androgenic alopecia in humans; Claim 1 was a "Swiss-type claim." Prior art included patents covering different ways of administering finasteride (topical or systemic) and for higher doses.

The Court of Appeal's January 30, 2015, Decision

In its decision, the Court of Appeal ruled that "although it is not required to clinically demonstrate the therapeutic...

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