Patent - Validity - Novelty - Obviousness - Insufficiency

Omnipharm Ltd v Merial: Chancery Division, Patents Court (Mr Justice Floyd): 21 December 2011

The claimant company sought the revocation of two patents, namely European patent (UK) No 0 881 881 and United Kingdom patent No 2 317 564 (the patents, or '881' and '564' respectively), both relating to treatments for protecting pets or small mammals from pleas, which were owned by the defendant. 881 had a priority date of 29 September 1995.

The specification explained that the purposes of the invention included ease of use, provisions of composition which did not require spraying of the whole animal body, and provision of compositions which, applied locally, would then spread over the animal's whole body and then dry, which avoiding as much as possible any crystallisation phenomenon. As originally granted, the specification described and claimed, as an active ingredient, a wide class of pyrazole compounds.

However, the claims were subsequently limited to fipronil, one of the two classes of parasiticide which emerged in the 1980s and contained a pyrazole. Claim 1 of 881 was stated as being: 'Composition useful for treating and protecting pets infested or likely to be infested with parasites, characterised in that it comprises in the form of a ready-to-use solution: (a) a [fipronil]; (b) a crystallisation inhibitor which meets [a glass plate test]; (c) an organic solvent with a dielectic constant between 10 and 35, preferably between 20 and 30; (d) an organic cosolvent with a boiling point below 100 degrees C, and a dielectic constant between 10 and 40, preferably between 20 and 30; wherein [fipronil] is present at the rate of 1 to 20% weight:volume in the composition'.

564 had a priority date of 29 March 1996, some six months after 881. 881 had not by then entered the state of the art. Like 881, it started life by claiming a large class of pyrazoles, but subsequently became limited to fipronil alone. The specification of 564 explained that the invention related to a composition for controlling mammal fleas, for example fleas on cats and dogs 'based on a synergistic combination of parasiticides which are already known'. The composition of the invention consisted of fipronil and 'at least one compound... of IGR (insect growth regulator) type'.

Preferred compounds of that type included methroprene and pyriproxyfen as well as others. The patentee explained that the two compounds, fipronil and IGR, might be administered separately in accordance with one embodiment of the invention, with one application being separated by the other in time, for example, one month. The specification described the application of the combined product as being 'deposited onto the skin ('spot-on' or 'pour on' application)... '. Claim 1 of 564 described: 'A composition which provides small mammals with longlasting protection against fleas, which includes, on the one hand, [fipronil] and on the other hand, at least one ovicidal compound (B), of insect growth regulator (IGR) type, in a fluid vehicle was is acceptable to the mammal and suitable for local application on the skin; wherein the fluid vehicle and the concentration of the [fipronil] and (B) were adapted for point application to the skin by deposition of the 'spot-on types; wherein the composition: [fipronil] is present in a proposition of from 5 to 15% [percentage as a weight per unit volume W/V); and (B) was present in a proportion of from 1 to 20% (percentage as a weight per unit volume W/V)'.

Parasiticides could be distributed in two ways: systematic and non-systematic distribution. Systematic distribution implied that the parasiticide was distributed through the bloodstream of the host animal such as by giving the animal a pill or capsule, or transdermally, by transmission through layers of skin and into the bloodstream. Non-systematic distribution involved delivering the parasiticide to the surface of the skin by spraying the animal all over.

The main methods of parasiticide application to animals were sprays, dips, shampoos, collars, spot-ons and pour-ons. The other methods of application had some drawbacks. Sprays were less convenient to apply than spot-ons and pour-ons, as the use of spray required multiple actions by the user. Further, small animals did not like the application of a spray and attempted to escape. The defendant's product, Fipronil, was launched as 'Frontline' spray in France in 1994. The product was sold as a pump spray action and the dog or cat would be sprayed all over so as to wet the coat.

It rapidly became recognised as a very effective product, better than anything else on the market. The claimant attacked both patents on the grounds of obviousness and insufficiency and sought certain declarations of non-infringement in respect of flea treatments which the claimant claimed it planned to sell. The defendant responded by making unconditional offers to amend the patents. Claim 1 of 881 was proposed to be amended by claim 1A, which was the same as claim 1 except that the introductory words were as follows: 'Composition useful for treating and protecting pets infested or likely to be infested with parasites, characterised in that it comprises, in the form of a ready-to-use spot-on solution for localised application on a surface area of less than 10 sq cm'. The proposed amendment to 564 involved a deletion of the description relating to separate administration of the two components.

In respect of 881, the claimant directed its primary obviousness attack at claim 1A. The defendant also directed the majority of its argument to claim 1A. The claimant submitted that the defendant's Frontline spray was obvious on the basis that: (i) it was obvious to try and develop a fipronil spot-on formulation once the efficacy and success of the Frontline spray had been known: spot-on formulations had an advantage in terms of ease application; (ii) given that the spray had functioned non-systematically, it had been obvious to try, at least in the first instance, formulating a non-systematic spot-on; and (iii) the task of formulating a non-systematic spot-on of fipronil would be given to a formulator, who would be able to come up with a formulation, within claim 1.

In respect of its insufficiency attack, the claimant alleged that the disclosure was no more enabling than that of the prior art and accordingly, the specification of the patent did not disclose the invention clearly enough for it to be performed by a person skilled in the art. In respect of 564, the claimant alleged: (i) that 564 was obvious in the light of an article by Donahue & Young (D&Y), published in 1992 in the journal of Veterinary Medicine which reported tests on a combination spray product which was a mixture of a pyrethoid and an IGR: the product was commercialised as Ovitrol Plus: (ii) that 564 was invalid for insufficiency on the basis that the directions in the patent were simply inadequate to enable the skilled person to arrive within the claims without undue effort; and (iii) the proposed amendment to the formulation by the deletion of the description relating to separate administration of the two components should not be allowed as it added matter to the formulation.

The court ruled: (1) The patents in suit were addressed to a team working in a veterinary healthcare company interested in the development of pesticides and their formulation. It was common ground that such a team at priority date would comprise a veterinary parasitologist and a formulation scientist. The skilled team would know of the existence of spot-on formulations of certain actives which had generally been thought to act non-systematically. The team would not have any common general knowledge theory as to how such formulations in fact spread over the body of the animal (see [39], [59] of the judgment).

(2) It was not sufficient to prove common general knowledge that a particular disclosure was made in an article, or series of articles, in a scientific journal, no matter how wide the circulation of that journal might be, in the absence of any evidence that the disclosure was accepted generally by those who were engaged in the art to which the disclosure related. A piece of particular knowledge as disclosed in a scientific paper did not become common general knowledge merely because it was widely read, and still less because it was widely circulated. Such a piece of knowledge only became general knowledge when it was generally known and accepted without question by the bulk of those who were engaged in the particular art; in other words, when it became part of their common stock of knowledge relating to the art (see [40] of the judgment). British Acoustic Films Ltd, Poulsen and Petersen v Nettlefold Productions [1936] 53 RPC 221 applied; General Tire and Rubber Co v Firestone Tyre and Rubber Co Ltd [1972] RPC 457 applied.

(3) The question of obviousness should be considered on the facts of each case. The court had to consider the weight to be attached to any particular factor in the light of all the relevant circumstances. Those might include such matters as the motive to find a solution to the problem the patent addressed, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectations of success. Expectation of success could be a relevant consideration, the weight to be attached to it depending on the facts of the case (see [85], [86] of the judgment).

In the instant case, the obviousness attack against claim 1A over the fipronil spray would be rejected. Even taking account of the motivation to achieve a more convenient application method than a spray, the skilled team would not have a sufficient expectation of success to render the invention obvious. The team would have no common general knowledge basis on which to make such a prediction.

The fact that other compounds had worked in spot-ons and pour-ons provided no technical basis for predicting that fipronil would do so, particularly when there was no scientific theory as to which properties of a compound, or characteristics of a formulation would make it do so. There was no evidence to suggest that the ability of a compound to distribute non-systematically was independent to its physico-chemical properties. The fact that fipronil was an efficacious compound in spray form did teach one that it worked by contact with the insect's cuticle, and could in theory be made to work as a spot-on provided only that it would spread the animal's body from the point of application.

The skilled team had no basis for predicting that that result could be achieved, or what formulation tools would be suitable for achieving that goal. Further, in respect of the obviousness attack on claim 1, it had not been established that it would be obvious to make such a formulation, not least because no theory had been advanced as to why that would be done with any real expectation of success. In respect of the insufficiency attack on 881, the evidence did not establish that the claims of 881 were invalid for insufficiency.

The fact that the skilled team would have to do some experiments based on the teachings of the specification and the examples in order to arrive at other spot-on formulations within the claim could not be regarded as adequately probative of insufficiency. It was true that the specification did not teach that the dermal theory of distribution was correct: it did not have to. What was important was that it provided sufficient practical guidance to enable the skilled person to work the invention across its full breadth. It had not been established that the guidance in the specification, starting with the examples, had failed to do that. Further, there was no basis for holding that the claim as amended was insufficiently enabled (see (see [124], [133], [134], [139], [143] of the judgment).

The obviousness attack against claims 1 and 1A of the fipronil spray would be rejected, as would the allegations of insufficiency (see [131], [139] of the judgment). Generics (UK) Ltd v H Lundbeck A/S [2007] All ER (D) 87 (May) applied; Pozzoli SPA v BDMO SA [2007] All ER (D) 275 (Jun) applied; Conor Medsystems Inc v Angiotech Pharmaceuticals Inc [2008] 4 All ER 621 applied; Saint-Gobain Pam SA v Fusion Provida Ltd [2005] IP & T 880 considered.

(4) In relation to the obviousness attack on 564, it had already been held that a spot-on formulation of fipronil would not have been obvious. The claims of 564 were narrower and therefore no more susceptible to an obviousness attack than 881. Nothing in D&Y, which related to a spray formulation of a different product, led to a different conclusion on that issue. However, in respect of the insufficiency attack on 564, it could not be said that the very broad indication of the components of the formulation, either in the main claims or the subsidiary ones, was a sufficient description to enable the skilled person to arrive at the formulation within the claims without undue effort. Consequently, the insufficiency attack would succeed. Further, the proposed amendment would be allowed. There were no grounds for the added matter objection to that amendment (see [146], [152], [153] of the judgment).

881 was valid, but 564 was not. The proposed amendments would be allowed. The claimant would be entitled to a declaration of non-infringement in relation to the formulations which were agreed not to infringe (see [159] of the judgment).

Henry Carr QC and Thomas Mitcheson (instructed by Fasken Martineau LLP) for the claimant; Andrew Waugh QC and Thomas Hinchliffe (instructed by Taylor Wessing) for the defendant.