European patent update – key decisions at the EPO and German Court

We cover some recent key decisions in European patent disputes, this time in the EPO and German Supreme Court.

Part 1 - T 1675/20 - Suitability for medical treatment has to be shown for each element of the claim

Relevance of the Decision

It is established practice of the Boards of Appeal (BoAs) of the EPO that where a therapeutic application is claimed in the form according to Article 54(4) or (5) EPC, attaining the claimed therapeutic effect constitutes a functional technical feature of the claim. As a consequence, in order to fulfil the requirements of Article 83 EPC, the suitability of the product for the claimed therapeutic application must be disclosed in the application, unless this is already known to the skilled person at the priority date (see decisions T 609/02, Reasons 9, and T 895/13, Reasons 3 to 5). T 1675/20 confirms that the application must contain information regarding the suitability of all claimed combinations for the therapeutic application. This makes it questionable to what extent broad therapeutic claims are available at the EPO and has implications on drafting strategy.

Decision

In T 1675/20 (decision of May 26, 2023), the BoA concluded the requirements of Article 83 EPC are not met because one of the embodiments - out of a number of combinations - in a broad therapeutic claim is not disclosed in the application in a manner sufficiently clear and complete for it to be carried out by a skilled person.

Reasons

T 1675/20 relates to a case wherein, in claim 1, the therapeutic use, in a first medical use claim, of a combination of (i) a first (prime) composition (comprising dendric cells) and (ii) a second (boost) composition comprising one of a number of co-stimulatory antibodies (anti-CD137, anti-CD40, anti-OX40, anti-ICOS, anti-CD27, anti-CD28, anti-GITR, or anti-TIM1). The application as originally filed contains data for a murine cancer model for the combination: with anti-CD40 antibodies. In addition, in vitro data are available in the application in relation to anti-CD137, anti-CD40, anti-CD134 (anti-OX40) or anti-CD278 (anti-ICOS), but not for anti-GITR and anti-TIM1.

In this way, there was a range of data in the application: at one end, the combination with anti-CD40 (both in vivo and in vitro data); at the other end certain combinations without any data (i.e. with anti-GITR and anti-TIM3). Interestingly, the dispute focussed on the middle of this range, in particular the combination with anti-ICOS and how its in vitro data compared to the data for the most credible combination with anti-CD40. In this respect, the anti-ICOS data were found not to be "credible"(interestingly choosing this word as opposed to "plausible"). Furthermore, as the data for this combination was obtained together with another factor (Poly I:C), the Board held that this further diminishing the ability to attribute the results to anti-ICOS.

As a result, the BoA concluded that it was impossible to conclude whether an anti-ICOS antibody has an effect on its own. As a result, the appeal was dismissed, and the whole application remained rejected under Art. 83 EPC.

Take Home Message

T 1675/20 shows the strict approach the BoAs are currently taking with respect to medical use claims. In this decision, interestingly, the BoA focussed on data in the application which showed that for one embodiment (with anti-ICOS antibodies), the therapeutic effect was not considered credible/plausible, while the Board did not discuss missing data for other embodiments. This shows that when preparing an application, the data contained in the examples should be very carefully evaluated, and any potentially non-working examples should be carefully assessed. Especially, care should be taken that for all commercially important embodiments, experimental data are available. This is particularly important given the requirement that sufficiency of disclosure (i.e. in the present context credibility / plausibility) needs to be fulfilled at the priority or filing date. In addition, given the strict requirements under added matter, suitable fall back positions need to be evaluated and explicitly disclosed already at the filing or priority date (and interestingly, the applicant did not pursue more limited claims to a subgroup of antibodies in this appeal).

Part 2 - German Supreme Court: Nexavar case shows a strong alignment on priority entitlement between German Court and the EPO Enlarged Board of Appeal, following decision in G1/22 and G2/22.

Relevance of the Decision

This decision shows strong alignment between Germany and the EPO on the issue of entitlement to priority, with the German Supreme Court agreeing with the reasoning in the recent G1/22 and G2/22 decisions of the Enlarged Board of Appeal. Entitlement to priority has featured extensively in national and EPO caselaw for more than a decade, resulting in extensive arguments and evidence on transfers of patents/inventions between priority and filing dates. This decision, like the EBA decisions, is likely to be welcomed by patentees, and could be the start of a wave of momentum across Europe following the EBA that significantly dilutes this type of priority attack. This case also addresses a number of other invalidity attacks, in particular highlighting the significant impact of experimental evidence and claim amendments on upholding inventive step.

Decision

This decision of the German Supreme Court was announced on 28 Nov 2023, following a long-running pan-European patent dispute between multiple pharmaceutical companies seeking to launch generic versions of Bayer's Nexavar® (sorafenib - a small  molecular, kinase inhibitor used to treat certain types of kidney, liver and thyroid cancers). This appeal was in the jointly heard cases between Ratiopharm (part of Teva) and STADA, and the decision followed an oral hearing on 10 Oct 2023 (interestingly, the same day that the decision in G1/22 and G/22 was delivered, actually after the hearing).

A single claim (claim 12) of the patent-in-suit (EP 2 305 255) was in issue, which a product claim for the tosylate salt form of sorafenib. Taking into account the second auxiliary request (the addition of the feature "in an oral dosage form"), the Supreme Court rejected inventive step and novelty attacks. The priority attacks (and intervening prior art) were rejected following the approaches in G1/22 and G2/22. There were no insufficiency attacks. 

Reasons

The claimants' attacks centred around the use of salt screens to find more soluble forms of otherwise very insoluble compounds (like sorafenib) with a view to improving their bioavailability for oral administration.

Parts of the claimants' argumentation was accepted and successful, with the Supreme Court agreeing with the decisions of the lower court that it was routine for the skilled team to perform a salt screening exercise and to select tosylate as one of the salt forms to try with sorafenib. Like the lower court, the Supreme Court rejected the defences up to this point concerning, for example, the complexity of this screening exercise and any potential alleged problems deterring the selection of tosylate. In this way, the Supreme Court agreed that the claim as granted - i.e. to the product alone - lacked inventive step.

However, the final defence for upholding inventive step concerned the persisting low solubility of even the tosylate salt form of sorafenib, not only as a matter of solubility but also its dissolution rate, was decisive. While the claimant could present experiments (and expert) evidence that routine dissolution tests do not show a preference for the tosylate the defendants failed to counter that. The Supreme Court was convinced that this was not so straightforward or routine, in particular given the different ways it might be undertaken on which the claimaint's experiments and publications cited by the defendants had debated at length.

Accordingly, with the feature "in an oral dosage form" added to the product claim (via auxiliary request 2), the Supreme Court held this would require the drug to be formulated as an oral dosage form ready for oral administration without further processing, which was not obvious following the salt screen given the low solubility and complexity and uncertainty of undertaking dissolution rate testing.  Of note, this was in contrast to the addition of "for oral delivery" to the claim (via auxiliary request 1), which was rejected as being insufficiently limited to being only suitable for oral administration.

The decision confirmed there was no added matter problem with the amendment and went on to reject novelty attacks (as the tosylate salt form was not disclosed pre-priority).

Despite G1/22 and G2/22 decisions being announced after the oral hearing, the Supreme Court held it could take them into account without a re-hearing. The Supreme Court agreed with the reasoning in the EBA decision and held that it was aligned with the position under German law. The decision emphasises that the burden of proof is on the claimants, who in this case had not made out with conviction that there was any ineffective transfer. The evidence submitted by the patentee (including a number, but not all of the assignments from the inventors), was found to be sufficiently convincing. The Supreme Court also refer to involvement of the priority applicants (individual inventors of a US patent application) in the PCT application, and so the patentee benefited from the rebuttable presumption discussed in the EBA decision in G1/22 and G2/22 - i.e. that this situation will suitably imply consent and transfer of the rights necessary for the EP applicant to preserve priority.

Take Home Messages

The case strongly suggests alignment between German law and the EPO caselaw following G1/22 and G2/22 with respect to priority, which is likely to significantly complicate the ability for parties who want to introduce this type of priority attack in their revocation actions.

This case also shows that a patentee can still maintain a patent at the last point and that experimental evidence - despite all issues connected with it - can support complexity that may successfully afront and defend inventive step in a sequence of events that the Court may have otherwise deemed to be a routine undertaking from the prior art up to that point.

And lastly, this case highlights the using the flexibility within national proceedings to keep options open by carefully considering even minor variations in conditional amendments.