Dutch court holds pemetrexed tromethamine does not infringe patent for pemetrexed disodium

July 2019

In its judgment of 19 June 2019, the District Court of The Hague1 (the Court) held in proceedings on the merits that Fresenius Kabi's generic pemetrexed tromethamine drug does not infringe EP 1 313 508 (EP 508) of Eli Lilly.

Eli Lilly holds EP 508 that relates to the use of pemetrexed disodium in combination with vitamin B12 for inhibiting tumor growth. Fresenius offers a generic drug which is almost identical to EP 508, the only difference is that it contains pemetrexed tromethamine instead of pemetrexed disodium. The question is whether Fresenius generic drug falls within the scope of protection of EP 508.

In these proceedings it was not in dispute that the literal wording of the claims is limited to pemetrexed disodium, while the person skilled in the art will recognize that the inventive concept underlying the words of the claim is not limited to pemetrexed disodium.

EP 508 derives novelty and inventiveness from the therapeutic use of the combination of pemetrexed and vitamin B12, and not from the choice for pemetrexed disodium. The skilled person therefore is aware that the literal text of EP 508 is more limited than the inventive concept.

The Court rules that the description of EP 508 does not contain any clear indication that protection for other forms than disodium is intended, in contrast to vitamin B12, for which various variants are mentioned both in the claims and in the description.

The skilled person will question why no other variant for pemetrexed has been mentioned, because he knows that it is (childishly) simple to manufacture pemetrexed in other forms than disodium as a dosage form.

In addition, the Court considers that due to the nature of the limitation and the way in which it has taken place according to the prosecution file, the skilled person will not regard the literal wording of EP 508 as a (clearly) unintended limitation.

It follows from the prosecution file that Eli Lilly initially tried to protect 'pemetrexed' but that it limited it into 'pemetrexed disodium' because the examiner raised an objection of added subject-matter. According to the Court, the original application provided sufficient basis to obtain a claim for all dosage forms of pemetrexed.

However, Eli Lilly did not attempt to obtain a claim that would include multiple forms of pemetrexed. Eli Lilly has not even entered into a discussion with the examiner about this. Instead, it has limited its claims without any struggle to pemetrexed disodium.

The Court rules that the aforementioned circumstances lead to the conclusion that EP 508 protects only pemetrexed disodium. Eli Lilly cannot take advantage from the fact that there is no technical reason for the limitation, because it made a conscious choice in limiting the claim. It must be considered possible and it would be obvious for Eli Lilly to have tried to obtain a broader protection.

Eli Lilly did not choose to do so, but instead has limited its claims. A lack of clarity should therefore come to the expense of Eli Lilly. The reasonable degree of legal certainty for third parties, which courts must keep in mind as a counter check, would not be sufficiently respected if the scope of protection of EP 508 would be expanded, meaning that this would include all dosage forms of pemetrexed.

Furthermore, the Court considers that the generic product does not infringe EP 508 under the doctrine of equivalents. The Court does not see why a limitation in the claim on the grounds of added matter during the grant procedure could be brought back into the scope of protection afterwards by relying on doctrine of equivalence. The doctrine of equivalence is not intended to undo in the formulation of EP 508 Eli Lilly's choices that they regret afterwards, at the expense of the reasonable degree of legal certainty of third parties.

The Court rules therefore that Fresenius' generic drug does not infringe EP 508.

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1 District Court of The Hague 19 June 2019, ECLI:NL:RBDHA:2019:6107 (Eli Lilly/Fresenius).


Judith Krens

Judith is a partner in our Amsterdam office, specialising in life sciences patent litigation.

Misja Boeken

Misja is an associate in our Eindhoven office, specialising in IP law.

"The Court does not see why a limitation in the claim on the grounds of added matter during the grant procedure could be brought back into the scope of protection afterwards."