T 1041/23, did the Opposition Division violate the right to be heard?

In T 1041/23 the decision of the Opposition Division (OD) that a clinical study stood in the way of novelty of granted patent  EP 2139494 was discussed.  

Claim 1 of the opposed patent was directed towards a granulate comprising one or more bulking agents, binders, disintegrants and, importantly, a specific solvate. A solvate is a substance that is in crystalline form and that has more than one compounds build in the crystal lattice. For the current case, the solvate concerned an equimolar combination of dapagliflozin, water, and propylene glycol. Dapagliflozin is a medicament to treat diabetes mellitus type 2. 

Tablets comprising this solvate were handed out in the clinical study. During the appeal there was no discussion on the public availability of these tablets, instead the discussion pivoted on the question if the specific solvate could be demonstrated in the tablets. Without such demonstration the tablets would not take away novelty of the claims. 

According to the Appellant (A) the OD’s decision mentioned for the first time that a skilled person could separate the solvate from the other ingredients of the tablet by dissolving the tablet and sieving out the insoluble solvate. This would amount to a violation of the right to be heard under Art. 113(1) EPC. 

The Appeal

During the opposition proceedings it was ab initio discussed if the solvate could be demonstrated in the tablets. The opponents argued that this could be done even without destroying the tablet. Several measurement methods were presented backed up by literature.  

There was no written dialogue on separating the solvate from the other components of the granulate. There was also no mentioning in the minutes of the oral proceedings. As noted in reason 1.3 of T 1041/23: 

“In this respect, the respondents emphasized the lack of details in the minutes of the oral proceedings before the opposition division, and submitted that, while they could not remember exactly, both the issues of separating the excipients from the crystalline material and of analysing the crystalline material had been a topic of discussion during these oral proceedings. However, the respondents do not dispute that the specific method of isolating the solvate from the tablet by dissolution in a physiological medium so as to analyse the crystal was never mentioned during the oral proceedings. There is no indication in the minutes of any discussion on this point either.” 

G 1/23 was discussed in the decision but did not play a role. G 1/23 concerned the question if a prior use product that cannot be reproduced and/or analysed is prior art. The Board reasoned that since the decision of the OD found the tablet analysable and therefore meeting G1/92, involving G1/23 would not change the Appeal.  

As the A claimed their right to be heard was violated, in reason 1.4 the Board first listed the criteria of Art 113(1) EPC: 

Then the Board explained that the decision was fully based on the idea that the tablets first had to be dissolved. The decision did not mention any other method for determining the solvate such as analysing the whole tablet. The dissolving and separating were therefore deemed an essential factual reasoning. Since the A was denied the possibility to comment on this essential factual reasoning, the Board concluded that the first-instance proceedings were affected by a substantial procedural violation.

Decision of the Board

The Board decided to remit the case to the opposition division. Moreover, as a further consequence of the substantial procedural violation, a reimbursement of the appeal fee was equitable under Rule 103(1)(a) EPC. 

Summary written by the NLO EPO Case Law Team