Validity of ‘second medical use’ patent upheld in UPC ruling

Patent law specialist Sarah Taylor of Pinsent Masons was commenting after the Milan seat of the central division (CD) of the UPC dismissed claims raised by Biogaran that a European patent with unitary effect (a unitary patent) owned by Lundbeck was invalid. Biogaran ran a series of invalidity arguments concerning added matter, sufficiency, inventive step and novelty, each of which was rejected by the court.

Taylor said: “While the decision may be appealed, the Milan CD has nevertheless provided practical guidance to both would-be rightsholders – for example, on the information they should include in patent applications for a second medical use limited to particular groups of patients – as well as prospective challengers, including how to frame attacks on the validity of such claims. Take aways from the ruling also apply more generally, with the court again emphasising the need to plead arguments up-front as well as the steps they need to take to fully substantiate invalidity arguments before the UPC.”

Second medical use patents are typically used to protect the use of a known compound or substance for a new medical purpose. They can therefore be highly valuable for the repurposing of known medicines for new diseases. 

In this case, Lundbeck's patent, EP 4 223 296 (EP’296) covered use of the known compound nalmefene for reducing alcohol consumption for a particular sub-group of patients. The claimed invention was in identifying that alcohol-dependent patients who drink at a high-risk level – more than 60g of pure alcohol a day for men, more than 40g for women – and who are still drinking at that level one to two weeks after their first assessment, responded well to treatment. 

Interaction between EPO and UPC proceedings

EP’296 is the final divisional patent in a chain of European divisional patents derived from an international ‘parent’ patent application, WO 2014/001427. Two of the chain’s earlier patents were revoked by the European Patent Office (EPO) – EP 2 866 808 at Lundbeck’s request, and EP 3 138 564 (EP’564) by the EPO Board of Appeal in opposition proceedings.

EP’296 is also the subject of an EPO opposition, and, Taylor said, “the present decision in respect of EP’296 usefully highlights the interaction between parallel EPO opposition proceedings and UPC proceedings”.

Following the issuance of the EPO opposition division’s preliminary opinion on the validity of the patent, the Milan CD allowed Lundbeck to unconditionally delete two of the dependent claims to align the patent claims litigated before the UPC with the amended claim text before the EPO. 

However, emphasising the front-loaded nature of UPC proceedings, the court refused to allow Biogaran to introduce a “substantially expanded line of argument” in the UPC action following the publication of the preliminary opinion.  “The court determined that these arguments had been available to Biogaran at the outset of the proceedings”, said Taylor. “To introduce them now would be unfair and would undermine procedural economy, so this is another warning to UPC litigants that sufficient preparation is essential.  Steps should be taken to ensure full arguments are pleaded at the outset which can be a significant hurdle for defendants in UPC proceedings who only have a limited three-month period in which to file their substantive defence, and developments before the EPO do not justify importing new arguments into a UPC case.”    

Guidance for litigants on UPC added matter pleadings

The front-loaded nature of UPC proceedings was further emphasised by the Milan CD’s assessment of Biogaran’s challenge to the validity of EP’296 on added matter grounds, and guidance it provided on pleading such objections in UPC proceedings.

Added matter arises where the matter disclosed in the specification of the granted patent extends beyond what was disclosed in the patent application as filed. 

Biogaran argued that the original application contained 135 embodiments giving rise to millions of possible combinations. It said the claimed combination could therefore not be directly and unambiguously derived from the original disclosure. 

“In its decision, the court stressed the importance of drafting discipline, with the burden being on the party alleging added matter to fully plead their case at the outset of the UPC proceedings,” said Taylor. “This requires the party alleging added matter to identify, by means of a specific comparison, the subject-matter of the original disclosure that is said to have been extended in the later application or divisional patent. The CD also emphasised the need for procedural fairness, requiring each party to plead its grounds of challenge clearly and with sufficient specificity.”   

“Further, the court clarified that while the mere fact that the original application may contain numerous embodiments and theoretically allow a very large number of combinations may point to clarity issues or poor drafting technique, it is not enough to establish added matter, and the court simply cannot step in to cure such pleading deficiencies of its own motion, as to do so would compromise its impartiality,” she said.

However, as the UPC Court of Appeal is yet to provide guidance on the degree of specificity required, the Milan CD nevertheless went on to undertake a limited comparison of the application as filed and the granted patent, EP’296. The court found a direct basis for the claimed combination in the application as filed and dismissed Biogaran’s added matter objections. 

Sufficiency of claims limited to a distinct patient subgroup

Disputes around sufficiency concern whether a patent application discloses the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. If it does not, the application is liable to be rejected or a patent already granted is liable to be revoked.

Biogaran advanced three insufficiency arguments, all of which were ultimately dismissed by the court. First, it said the exclusion of a certain group of patients from Lundbeck’s clinical trials meant the therapeutic effect was not credible across the full scope of the claims. The court dismissed this argument, finding that the fact that certain categories of patients were excluded from the clinical trials does not mean that the claimed therapeutic effect lacks credibility for those patients.

Taylor said: “The court found that Biogaran’s allegations were not supported by verifiable facts but were rather doubts about whether the effect would not be achieved in other patient groups. It is common in clinical trials to exclude certain groups for a range of reasons including safety and internal validity checks, but the court found that this does not amount to a lack of credibility of the claimed technical effect.”   

Second, Biogaran claimed that the invention was insufficiently disclosed because although the patent describes a form of motivational or emotional support as being necessary, such support is not reflected in the claims. It further argued that Lundbeck had not demonstrated that the treatment can be achieved without such motivational support. The court found that there is no requirement for every ancillary condition of the pre-clinical protocol to be reproduced in the claim, and the absence of motivational support from the claim does not render the invention insufficiently disclosed. 

Third, Biogaran took issue with the lack of precise dosage specified in the patent application: the clinical studies in the patent used an 18mg dose, but the independent claim contained no dosage limitation. The court rejected this argument, holding that the invention related to the selected patient sub-group not the dosage, and the prior art already indicated efficacy within the patent’s stated dose range. The court said that the skilled person “on the basis of the patent, the prior art and common general knowledge, can select a safe and effective dose without undue burden in the exercise of their routine competence”.

Role of hindsight in an inventive step assessment

Biogaran also argued that EP’296 was invalid on the ground of obviousness. To pass the obviousness test, applicants must be able to show that their new product or process delivers an inventive step – i.e. there is a substantive technical advance that someone skilled in the relevant area would not be able to work out easily using their own know-how and information available to them.

Applying the legal test for determining whether a European patent satisfies the inventive step requirement set out by the UPC Court of Appeal last year, the court regarded two pieces of prior art – a paper entitled Karhuvaara et al and Lundbeck’s 2011 corporate press release – as realistic starting points, but neither contained pointers to the proposed solution. Biogaran cited various other documents to bridge the gap, but none were considered to supply a technically credible reason to substantiate its claims of obviousness. In comments which apply beyond pharmaceutical disputes, the court said that an attack constructed by selecting and combining more than 10 documents dealing with different technical questions, none of which supplied the missing pointer, indicated hindsight and ‘ex post facto’ – retrospective – analysis which would not be undertaken by a person skilled in the art when assessing the patent’s validity.

As a final take away for UPC litigants in all sectors, Biogaran also tried to argue that the EPO’s revocation of the earlier patent, EP’564, had ‘res judicata’ effect before the UPC, meaning that the court could not then determine the validity of the patent at issue in this dispute, EP’296. However, the CD emphasised that although the two patents are related, they are legally distinct. Further, the EPO and UPC belong to distinct legal systems and exercise jurisdiction under different legal frameworks. Therefore, the EPO’s decision in respect of EP’564 does not bind the UPC in respect of EP’296. 

Biogaran was ordered to pay costs, which the court valued at €2 million. The company has two months from the date of the ruling to appeal.