Dosage inventions and inventive step: the strict reading of the French court
The dosage patent occupies a singular place. It protects not a new molecule but the way of administering it. It often arrives at the end of the cycle, once the product patent and its certificate have expired, and that is precisely when it is attacked. A judgment of the tribunal judiciaire de Paris shows how strictly the French court examines it.
What the court decided
By a judgment of 28 March 2024, the tribunal judiciaire de Paris revoked the French part of a European patent covering the administration of rivaroxaban in a single daily dose, in a dispute between the proprietor and a manufacturer of generic medicines. The product patent and the supplementary protection certificate having expired, the only remaining barrier lay in that dosage claim.
The court did not dwell on patentability in principle. It ruled oninventive step. L’état de la technique described administration in two daily doses but expressly invited the skilled reader to explore a single daily dose. The difficulties relied on by the proprietor arose from the uncertainties of clinical trials, not from any technical obstacle specific to the claimed solution.
A dosage regimen is patentable, but it must bring something more
The decision does not call into question the patentability of dosage inventions. Since decision G 2/08 of the Enlarged Board of Appeal, a new dosage regimen may support a second medical use. The debate has shifted downstream, to the real technical contribution.
The reasoning is orthodox, and that is what makes it formidable. Where the prior art suggests the route, merely demonstrating that it works is not enough. What is required is a different technical teaching, an effect theperson skilled in the art did not expect, or a technical prejudice overcome.
Why inventive step is the real filter
Proprietors often build their defence on patentability, the ground on which they have won. Competitors attack on inventive step, the ground on which they win more often. The uncertainties of a clinical trial do not in themselves amount to a technical difficulty within the meaning of patent law: the French court treats them as a development risk, one that ordinary precautions allow to be managed.
This reading converges with the wider criticism addressed to strategies ofevergreening, without the court needing to invoke it. It is enough to apply Article 56 of the European Patent Convention with rigour.
The gap with the European Patent Office
The same patent may survive opposition before theEuropean Patent Office and still fall before the national court. The gap does not stem from a divergence of rule, but from the way the technical contribution is assessed in the light of the evidence actually produced. For a generic manufacturer, a lost opposition does not close the debate. For an originator, a won opposition does not secure the patent.
Before the Unified Patent Court, the same patent would be subject to a révocation action whose most frequent outcome is, as our statistics show, maintenance in amended form rather than outright revocation. The choice of forum is therefore not neutral for a dosage claim.
What this changes in practice
For the proprietor, the rule of conduct fits in a single sentence: a dosage claim is not defended with efficacy data, it is defended with whatever, in the prior art, pointed away from the solution. That material is prepared at filing, not in litigation. Auxiliary claims must be framed in the same exercise.
For the competitor, the lesson is symmetrical. The most effective attack does not bear on the patentability of the dosage regimen but on the suggested character of the route followed, documents in hand. Timing counts as much as substance, since the expiry of the supplementary protection certificate opens the useful window.
Decisions in the sector are tracked one by one in Pharma Litigation Watch. Our firm litigates these disputes before the French courts and before the UPC, in particular as correspondent in France for patents and the UPC. Contact us.
This article is an updated adaptation of an analysis by Matthieu Dhenne originally published on Kluwer Patent Blog on 23 September 2024: Strict interpretation of the patentability of dosage inventions under French law. Official source: tribunal judiciaire de Paris, 28 March 2024, RG no. 22/08612.