Wednesday, 28 December 2011

T 468/09 – Don’t Focus On The Negative

The patent proprietor filed an appeal after the Opposition Division (OD) had revoked the patent under consideration because it found the disclosure not to be sufficient within the meaning of A 100(b).

Claim 1 of the main request before the Board read:
A urinary catheter assembly comprising at least one urinary catheter (1) having on at least a part of its surface a hydrophilic surface layer (6) intended to produce a low-friction surface character of the catheter by treatment with a liquid swelling medium prior to use of the catheter and a catheter package (7, 16, 29, 34, 42, 46, 51, 51’) made of a gas impermeable material and having a cavity (11, 18, 39, 48, 53) for accommodation of the catheter (1, 58, 69), characterized in that the cavity accommodates said liquid swelling medium for provision of a ready-to-use catheter assembly.
The appellant argued that the gist of the claimed invention was to provide an assembly for intermittent catheterisation, wherein the catheter could be withdrawn from the package in a condition which was suitable for insertion into the urethra. In order to put the invention into practice, the skilled person had to provide the urinary catheter with a hydrophilic surface layer, a package made of a gas impermeable material, to place the catheter and a liquid swelling medium in the package and to close the package. Urinary catheters with hydrophilic surface layers were known at the priority date of the patent in suit, and so were gas-impermeable packages. On the basis of the disclosure of the opposed patent and his common general knowledge, the skilled person would have no difficulty in carrying out the catheter assembly in the claimed manner, no matter if the liquid swelling medium were to be placed in direct contact with the catheter surface or in a storage body from which it was released. The subject-matter of claim 1 of the main request covered both embodiments and did not require storage of the catheter for years. The stability of the catheter coating was not an essential feature in the present patent.

Opponent 1 pointed out that the invention as claimed was restricted to the embodiments in which the coating was in contact with the liquid swelling medium (water) from the time of manufacture until use of the catheter, which could be up to 5 years later. It was essential that the coating be capable of being stored for the duration of this period without deterioration. Although not specified in claim 1, the recommended time period was, however, implicit. The subject-matter of claim 1 did not include the embodiment in which coating and liquid were kept apart until immediately before use, by confining the liquid in a spongy body. At the time the patent was filed, a skilled person was not able to produce without undue burden a hydrophilic catheter coating that could withstand wet storage for the required shelf life, i.e. avoiding deterioration of the coating. The patent was silent on how to solve this problem with the coating, namely how to provide a pre-wetted catheter assembly which could be stored for up to 5 years, typically 36 months, thus resulting in a long term preservation of the low friction surface characteristic of the catheter until its use. The evidence provided by the appellant clearly showed that the prior art coatings were not suitable. None of the catheters disclosed in the prior art cited in the patent was intended for wet storage. There was no indication in the patent of how the hydrophilic coating catheter could be made.

Opponent 2 argued along similar lines.

[4.1] A 100(b) states that an opposition may be filed on the ground that the European patent does not disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art. The requirement is the same as for A 83, which addresses the European patent application before grant.

It is established case law that sufficiency of disclosure must be assessed on the basis of the patent specification as a whole, including the description and the claims. Moreover, the disclosure is only regarded as sufficient if it allows the invention to be performed in the whole range claimed, i.e. for all embodiments falling within the ambit of the claimed subject-matter.

[4.2] Essentially, claim 1 of the main request defines a urinary catheter assembly comprising a urinary catheter and a catheter package;
  • the urinary catheter has on its surface a hydrophilic surface layer (coating);
  • prior to use, the hydrophilic surface layer is brought into contact with a liquid swelling medium to produce a low-friction surface;
  • the catheter package is made of a gas impermeable material and has a cavity;
  • the cavity accommodates the catheter (preamble of claim 1) and the liquid swelling medium (characterising portion of claim 1) for provision of a ready-to-use catheter assembly.
Claim 1 of the main request covers the two embodiments which are disclosed in the patent specification.

[4.3] In a first embodiment, shown in Figures 1 and 2, the catheter package 7 is formed by two sheets 8 and 9 of gas impermeable material welded together along a seam 10 (joint) so as to define a cavity 11 for accommodating a catheter tube 2 and a compartment 12, spaced apart from the cavity by an transitional section 13 […] for accommodation of a liquid swelling medium confined in a storage body 14 made of a spongy or gel-like material […].

The catheter and the spongy body are arranged in the package prior to welding the sheets of gas impermeable material together, in order to form the urinary catheter assembly. This clearly means that the package 7 encloses both the cavity and the compartment […].

Prior to use of the catheter, the hydrophilic surface layer 6 (coating) is prepared for activation of its low friction character by squeezing the liquid out of the body in order to allow it to flow into the cavity and to bring the catheter into a ready-to-use condition […].

This first embodiment, therefore, corresponds point by point to the wording of claim 1 in suit and, contrary to [opponent 1’s] assertion, falls within the scope of said claim. In particular, the hydrophilic coating of the catheter which is accommodated in the cavity is activated “prior to use” by treatment with the liquid swelling medium (preferably water - see paragraph [69]) within the cavity for provision of a “ready-to-use” catheter assembly.

This embodiment can readily be carried out on the basis of the information given in […] the description. This was not contested by the respondents either.

[4.4] In a second embodiment, not shown in the figures, the spongy body 14 is not used. The liquid is introduced into the package during the assembly operation, prior to the welding of the joint. In this case, the compartment for the liquid swelling medium is integrated with the cavity for accommodation of the catheter, the coating being prepared and activated immediately after completion of the production process when the liquid has been introduced into the package […].

This embodiment is made possible due to the gas impermeable characteristic of the material of the package. As explained in […] the patent, this should be understood as a material sufficiently tight to avoid diffusion by evaporation of the liquid, so as to prevent the coating from drying out and to preserve its low friction character for a long time […]. A period exceeding the shelf life of the catheter is recommended, which could be up to 5 years but is typically 36 months.

It should be noted here that the disclosed range is not limited at the lower end and therefore does not exclude much shorter periods of e.g. a few months, though such interpretations should be ruled out which do not make any technical or commercial sense, such as a zero length period or a period of a few days. Moreover, the time period of 36 months is given as an example (“typically”; “recommended”). The important matter is to keep the coating activated and the catheter in a ready-to-use condition “at all times” […], i.e. within the time period corresponding to the above defined range.

Claim 1 does not mention any duration for the preservation of the coating, i.e. the period between the time of activation of the coating and the time at which a catheter is used. Therefore the subject-matter of claim 1 also covers the second embodiment since “prior to use” corresponds in that case to the activation of the coating at the time the catheter assembly is produced. From that time onwards, the catheter assembly is “ready-to-use”, in accordance with the wording of a claim 1.

[4.5] As can be derived from the patent specification, the problem underlying the claimed solution is principally to avoid diffusion by evaporation of the liquid swelling medium in order to protect the activated coating from drying out […]. This result is achieved by the gas impermeable characteristic of the material constituting the package, not by a characteristic of the coating. Therefore, the respondent’s arguments based on maintenance of the coating stability and of its coherence over time by avoiding its dissolution in the liquid are irrelevant and not convincing.

The same is true for the problem formulated by the OD of avoiding the coating reacting with the material inside the bag or dissolving into water.

[4.6] It results therefrom that all the discussions about the characteristics of the coating appear to be irrelevant for the assessment of sufficiency of disclosure and of the reproducibility of the catheter assembly as claimed. The same applies to the document cited by both parties in support of their arguments regarding the properties of the coating.

Having regard to the broad definition of claim 1 and given that the gas impermeable material of the package provides sufficient tightness against evaporation of the liquid for a period of time which could vary considerably (“up to five years”), the known catheters referred to in […] the patent specification could be suitable in any case and on the basis of this disclosure the invention can be carried out, even if such catheters may suffer from some other deficiencies. A 100(b) does not require that the best mode be performed.

Where a disadvantage of an invention could (possibly) prevent its use, this is not an obstacle to reproducibility provided that the otherwise desired result was achieved by the technical teaching disclosed in the patent (see also T 881/95). This is obviously the case here since the only problem addressed by the contested patent is confined to preventing evaporation of the liquid from the package and subsequent drying of the catheter coating, and this is solved by the provision of an appropriate material for the package. The coating stability of a catheter immersed for a long period of time is not an issue. Under the circumstances, it matters little whether, at the priority date of the contested patent, catheter coatings capable of withstanding water storage over a long period of at least 36 months were available or not.

[4.7] For the foregoing reasons, the requirements of A 100(b) are satisfied.

The case was then remitted to the OD for further prosecution.

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The file wrapper can be found here.