The so-called doctrine of equivalence (DOE) was reputed to be dead before the Courts in Europe. Now DOE has been revived overall in Europe. This means that if your patent claims state “disodium”, the patent can be nevertheless infringed by a different salt exhibiting equivalent effects.

As the European Patent Office gets stricter and overly formalistic and tends to restrict the claims to just a bit more than the examples, it seems that the courts “heal” that formalistic defect to provide a reasonable scope of protection to the patentees. The patent in suit related to a combination therapy of pemetrexed and vitamin B12 for the treatment of cancer. Eli Lilly’s patent claims said a combination of vitamin B12 together with a specifically specified salt: pemetrexed disodium. The question is whether generic companies can circumvent these claims by using a different salt.  The CoA stated that the limitation “disodium “ was introduced to overcome an objection on the basis of “added matter” (Art. 123(2) EPC), which cannot limit the patent’s scope of protection. “Added matter” is a very formalistic objection before the EPO. If the applicant had originally claimed all salts, it may be possible that he cannot get the broad scope as there are e.g. not enough examples in the description to make it plausible that all salts would work. In such a case, he has to fall back on specifically specified salts as described in the original description. It depends on the efforts the applicant has undertaken of specifically naming all possible salts how broad the final scope may be – in this case only disodium.

According to the CoA, the fact that including not specifically mentioned equivalents in the patent document during prosecution is prohibited on the basis of “added matter” does not preclude claiming protection for those same equivalents before a national court.Good news for those who have experienced the bane of the “added matter” concept of the EPO that makes it hard to get adequate protection if the patentee has not performed the annoying exercise of writing down all of the millions possible and known equivalents.

However, one has to admit that there is a lack of legal security about what is encompassed by the patent if the patentee has to rely on the DOE later before the courts instead of getting adequate protection from the EPO early on.

Dr Ute Kilger (German Patent Attorney and European Patent and Trademark Attorney, Partner at
Boehmert & Boehmert) specialises in all kinds of patent-related issues concerning the obtaining and enforcement of property rights, due diligence, mergers and acquisitions, contract negotiations, and licensing agreements.

This article was published in the European Biotechnology Magazine Winter 2020.