EP 3 525 706 B1 relates to the field of Cold Atmospheric Plasma (CAP) treatment of therapy-refractory Actinic Keratosis, wherein the cold atmospheric plasma is an argon-containing plasma.
Brief outline of the procedure
The OD rejected the opposition and Opponent 2 appealed.
The board decided that claim 1 as granted lack IS over D1=US 2013/0345620 in view an expectation of success. The same applied to AR1-5.
The patent was thus revoked.
The proprietor’s point of view
Art 54(4+5) – substance or composition
The “argon-containing plasma” as defined in claim 1 as granted was generated by ionisation of argon gas, and it contained argon only in the form of argon ions.
In line with decision T 2003/08 and with reference to G 5/83, the term “substance or composition” referred to products which qualified as chemical entities or compositions of chemical entities. The products further had to be the active agent in the medical use.
In accordance with T 1758/15, a product was a substance or composition within the meaning of Article 54(4+5) if both:
- (i) the therapeutic effect was achieved by the substance or composition
- (ii) the achievement of the therapeutic effect could be ascribed to the chemical properties of the substance or composition
The therapeutic effect was ascribed to the chemical properties of the composition as a whole. In the case at hand, the therapeutic effect of the plasma composition was shown by experimental data in the patent.
It was furthermore not required that the therapeutic mechanism was entirely clear.
Art 54(5) – selected patient group
The therapeutic use as claimed in claim 1 related to the treatment of a subgroup of patients suffering from actinic keratosis, namely patients who had been previously treated with standard medication which, however, had not resulted in a satisfactory treatment and/or clearance of the disease.
This group of patients was not disclosed in the prior art.
Article 56 EPC – inventive step starting from D1
Claim 1 was directed to a second-line treatment of actinic keratosis in which argon-containing CAP was used for treating a group of patients who were resistant to a previous first-line treatment.
T 1491/14 was the most relevant case law for new therapeutic applications based on a new group of patients to be treated. This decision applied mutatis mutandis to the case at hand.
Starting from D1, it would not have been obvious for the skilled person to select the subgroup of patients being therapy-refractory to a first-line treatment for use in the treatment in a second-line medication with argon-containing CAP.
The board’s decision
For the board, it was undisputed that both CAP itself and its use in the treatment of actinic keratosis are comprised in the state of the art, as acknowledged in the patent.
Art 54(4+5) – substance or composition
For the board, it was undisputed by the proprietor that the claimed plasma contains a variety of charged and neutral components. The only chemical entity explicitly mentioned in the claim is argon, without specifying whether it is in the form of ions.
As the biological mode of action remained “unclear”, it could thus not be ruled out that it is the photons and/or the UV light, i.e. subject-matter other than a substance or composition, which are responsible for the alleged therapeutic effect.
For the sake of argument and in the proprietor’s favour, it was assumed that the alleged therapeutic effect is indeed caused by the parts of the claimed plasma that qualify as a substance or composition within the meaning of Arti 54(5).
Art 54(5) – group of patients
Three criteria are mentioned in T 1491/14 have to be fulfilled for the treatment of the same disease with the same substance in a specific group of patients to be considered a new therapeutic use:
- (i) the patient group is not disclosed in the relevant prior art
- (ii) the patients belonging to the group can be distinguished from those of the prior art by their physiological and pathological status
- (iii) there is a functional relationship between the characterising physiological or pathological status and the therapeutic treatment, and thus the selection of the patients is not arbitrary
For criterion (i), the board accepted that such a group of patients was not disclosed in the PA, which however, does not disclose whether these treatments were successful.
For criterion (ii) to be fulfilled, the determination of the group of therapy-refractory patients requires a previous non-successful treatment. Hence, the claimed use is not directed to non-treated patients.
The board added that, it is not required that the technical effect be surprising for criterion (iii) to be fulfilled.
All three criteria were thus fulfilled.
Article 56 EPC
From D1 the skilled person learns that treatment with CAP is effective against actinic keratosis in patients who suffer from side effects involved in previous treatment with imiquimod.
Knowing that, the person skilled in the art would have had a reasonable expectation that patients who were refractory to other therapies, including imiquimod, could particularly benefit from the CAP treatment.
D1 discloses that the CAP treatment avoids the disadvantages and side effects of current actinic keratosis therapies like topical or systemic drugs or heating therapy.
The proprietor did not provide any evidence demonstrating that the therapeutic effect of the plasma treatment was due to the fact that the plasma contained argon species.
Comments
The present decision shows how to apply Art 54(5), but even if the claim relates to the use in a well-defined group of patients, what eventually matters is to decide whether there was a legitimate expectation of success.
As this was clearly the case, the new use could not be considered inventive.
D1 was mentioned in categories X,Y in the ISR established by the EPO.
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