Patent dependency

Patent dependency arises where an invention protected by a patent cannot be worked without infringing an earlier patent belonging to a third party. The later patent, known as the dependent or improvement patent, is valid, but working it requires the authorisation of the holder of the dominant patent. The French Intellectual Property Code deals with this situation in Article L. 613-15, which allows the holder of the dependent patent to obtain, under certain conditions, a compulsory licence of the dominant patent, and vice versa, in line with the TRIPS Agreement, which permits this type of licence for dependent patents.

The dependency situation

Dependency results from the combination of two valid patents: the second claims a new and inventive invention, for example an improvement, a particular application or a selection, whose implementation reproduces the features claimed in the first. The holder of the improvement patent therefore cannot work the invention without committing patent infringement, while the holder of the dominant patent cannot work the improvement without infringing the second patent.

Compulsory licence for dependency

The holder of the dependent patent may apply to the court for a compulsory licence of the dominant patent where the invention represents important technical progress in relation to it and is of considerable economic interest. The applicant must show that a licence could not be obtained by agreement on reasonable terms. The licence granted is non-exclusive, limited to what is needed to work the dependent patent and subject to a royalty set by the court. The holder of the dominant patent may in turn obtain a licence of the dependent patent, so that the mechanism leads to a cross-licence. The Paris Judicial Court has exclusive jurisdiction over the application. In practice, this procedure is rarely brought, the threat of a compulsory licence serving mainly as leverage in negotiating a cross-licence.

Practical and litigation implications

Dependency is a major risk revealed by a freedom-to-operate analysis, which must not be confined to the applicant’s own rights but should examine the earlier patents still in force in the field. Obtaining a patent on an improvement is never a defence to an action for infringement of the dominant patent, and the defendant cannot rely on its own patent to justify working the invention. Dependency ends when the dominant patent expires or is declared invalid.

Key points

Patent dependency describes the position of a valid patent whose working infringes an earlier patent. The holder of the dependent patent may obtain a compulsory licence by showing important technical progress and considerable economic interest, after a failed attempt at negotiation, and the dominant patentee may obtain a licence in return. Before any launch, a freedom-to-operate analysis should check for dominant patents and a licence should be negotiated, since owning a patent never protects against an action by the holder of an earlier one.

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This glossary entry is general in scope and does not constitute legal advice.

Dhenne Avocats litigates patent disputes before the Paris Judicial Court, the Paris Court of Appeal and the Unified Patent Court. When the question arises in a real case, the right moment is almost always before proceedings are issued.

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