In Europe, Article 54(5) EPC allows for the protection of known compounds or compositions in the form of claims directed to the use of said compounds or compositions in medical methods of treatment, so long as that particular use is not also already known. For such medical use claims, the decision of the Board of Appeal in T 609/02 established that for the purposes of sufficiency of disclosure, the application must disclose the suitability of the product for the claimed therapeutic application, unless this is already known to the skilled person at the priority date.
The recent decision T 728/21 provides an example of what the Boards of Appeal consider the term "already known to the skilled person" to encompass, particularly in view of the Enlarged Board of Appeal's recent decision G 2/21, which related to the plausibility of a purported technical effect.
Case Background
The patent in question related to a pharmaceutical composition comprising, inter alia, a solid dispersion of 80 wt% amorphous ivacaftor for use in the treatment of cystic fibrosis. The treatment was further defined in that it was administered alongside at least one other therapeutic, and was restricted to the subgroup of patients possessing a cystic fibrosis transmembrane receptor (CFTR) with a ΔF508 mutation on both alleles.
At first instance, the Opponent successfully argued that ivacaftor was not effective in the treatment of the claimed subgroup of patients, resulting in the Opposition Division concluding that the patent as granted was insufficiently disclosed. This deficiency was found to be overcome in Auxiliary Request 16, which included the additional feature that the other therapeutic agent is a CFTR modulator other than ivacaftor. Both parties appealed the decision, however the Proprietor later withdrew their appeal.
Inventive Step
In their arguments for an inventive step, the Proprietor relied on post-published experimental data which in their view demonstrated that improved tablet dissolution was obtained using the claimed composition.
The Board considered whether the post-published data could be used to support a technical effect by applying the test of G 2/21 – i.e., establishing whether the skilled person, having the common general knowledge in mind, and based on the application as originally filed, would derive said effect as being encompassed by the technical teaching and embodied by the same originally disclosed invention.
In reaching their decision, the Board concluded that the application as filed explicitly addressed the dissolution of tablets comprising a solid dispersion, and thus evidence of improved dissolution could be taken into account. Since none of the cited documents taught that improved dissolution could be obtained by using the specific amounts of excipients and dispersion, the Board concluded that the claims were inventive.
Sufficiency
For a claim to be sufficiently disclosed in Europe, Article 83 EPC states that the application must disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. As noted above, for medical use claims this means that the application must render it credible that the claimed composition is suitable for the stated therapeutic use as of the filing date.
Although the Enlarged Board of Appeal's decision in G 2/21 was in the context of a technical effect for inventive step, the same considerations also apply to credibility for sufficiency of disclosure (see G 2/21, section 74). In other words, the lack of a plausible disclosure in the application of the suitability of the claimed composition for a therapeutic use cannot be rectified by post-published evidence.
In the present case, the Board found that the patent provided a rational basis for the claimed invention. In brief, the patent set out the effects of the ΔF508 mutation in patients with cystic fibrosis, identified ivacaftor as being a potent CFTR potentiator (i.e., it increases the sensitivity of CFTR to other drugs), and taught that ivacaftor could be combined with other CFTR modulators. In the Board's view, these teachings represented "specific and verifiable technical information supporting the defined therapeutic indication" which rendered the claimed treatment of ΔF508 patients credible at the effective date.
Having established that the patent itself provided a rational basis for the claimed invention, the Board went on to consider whether the suitability of the claimed treatment was "already known" in the sense of T 609/02. In this regard, the Board highlighted disclosures in the prior art that ivacaftor is a CFTR potentiator, and that it may be used in the treatment of patients with a ΔF508 mutation. Thus, even though these disclosures were from prior art and not considered to form part of the skilled person's common general knowledge, the Board was of the view that they confirmed the credibility of the utility of the claimed composition.
Once it has been established that a patent provides a credible disclosure of the claimed invention, it is still possible in Europe for there to be a lack of sufficiency if it is shown that there are serious doubts, substantiated by verifiable facts, that the skilled person cannot carry out the claimed invention without undue burden.
To this end, the Opponent put forward two arguments relating to the skilled person's ability to carry out the claimed invention. First, the Opponent highlighted the results of a clinical trial allegedly showing that ivacaftor did not provide a statistically significant clinical benefit. The Opponent then argued that the risk of potential drug-drug interactions was such that the skilled person was faced with an undue burden in identifying which other CFTR modulators ivacaftor could be safely combined with. However, the Board was not convinced that either of these reasons met the high standard of "serious doubts substantiated by verifiable facts", and thus concluded that the claims were sufficiently disclosed.
Conclusions
The decision in T 728/21 provides confirmation of two developing areas of European practice. First, the decision affirms that the considerations of G 2/21, which focused on the use of post-published data to support an inventive step, also apply to credibility for sufficiency of disclosure. Secondly, it emphasizes that prior art may be used to demonstrate that an invention is sufficiently disclosed, even if this is not common general knowledge. As such, the conclusions drawn from T 728/21 are likely to be welcome to patentees in Europe.
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