What is Common General Knowledge?
A look at the recent decision in Teva UK Ltd v AstraZeneca AB  EWHC 2873 (Pat)
Teva has successfully revoked a patent owned by AstraZeneca for the treatment of asthma for lack of inventive step. Mr Justice Sales also rejected AstraZeneca's attempts to amend the claims concluding such amends would constitute added matter. The case is noteworthy for two reasons: firstly, the judgment contains an interesting discussion of what should constitute Common General Knowledge (CGK), including an attempt by Mr Justice Sales to update the current approach taken to establishing CGK; and secondly, the Judge had to re-write parts of his draft judgment, something which rarely happens.
The patent in suit, owned by AstraZeneca, concerned a therapy for asthma which combined formoterol (a bronchodilator) and budesonide (an inhaled corticosteroid (ICS) with anti-inflammatory action) in a single inhaler which could be used both for regular treatment of asthma (referred to as "maintenance" use) and for the treatment of acute attacks (referred to as "relief" use).
Teva sought to revoke the patent saying it was invalid for lack of novelty and inventive step. Teva submitted that the invention (use of formoterol and budesonide for maintenance and relief use in the same dose) was obvious in light of an earlier patent (the 1993 Patent) and the CGK. Of particular interest is Mr Justice Sales' discussion of what constituted the skilled person's CGK.
CGK – a new approach?
It was common ground that CGK would include statements in standard reference works and leading journal articles. In addition, Mr Justice Sales considered a number of "primary articles" which he described as "academic articles…sufficiently prominent in the main academic journals in the field" also to be part of the CGK. The above is unsurprising and is in keeping with the authorities on CGK. However, what is of interest is the fact that the Judge then went onto describe two further categories of CGK, "secondary articles" and "tertiary articles".
Mr Justice Sales described "secondary articles" as a range of articles that were not leading journals in the field, and would not have been likely to have been read by the notional skilled person in the ordinary course of keeping himself up to date. He felt these should be included since these materials would have been quickly identified by any person conducting a literature search and review into the use of formoterol and ICS in relation to the treatment of asthma. At paragraph 60, Mr Justice Sales provides his justification as follows:
"The authorities indicate that CGK includes not just information directly in the mind of the notional skilled person, but such information as he would be able to locate by reference to well-known textbooks. This guidance needs to be adapted and kept appropriately up to date for the procedures for dissemination of scientific knowledge in the age of the internet and digital databases of journal articles. Searches of such databases are part and parcel of the routine sharing of information in the scientific community and are an ordinary research technique. In my view, if there is a sufficient basis (as here) in the background CGK relating to a particular issue to make it obvious to the unimaginative and uninventive skilled person that there is likely to be — not merely a speculative possibility that there may be — relevant published material bearing directly on that issue which would be identified by such a search, the relevant CGK will include material that would readily be identified by such a search."
This approach appears to widen the concept of CGK as established by earlier authorities. For example Laddie J at paragraph 40 in Raychem Corp's Patents  RPC 31 stated as follows:
"The common general knowledge is the technical background of the notional man in the art against which the prior art must be considered. This is not limited to material he has memorised and has at the front of his mind. In includes all that material in the field he is working in which he knows exists, which he would refer to as a matter of course if he cannot remember it and which he understands is generally regarded as sufficiently reliable to use as a foundation for further work or to help understand the pleaded prior art. This does not mean that everything on the shelf which is capable of being referred to without difficulty is common general knowledge nor does it mean that every word in a common text book is either. In the case of standard textbooks, it is likely that all or most of the main text will be common general knowledge. In many cases common general knowledge will include or be reflected in readily available trade literature which a man in the art would be expected to have at his elbow and regard as basic reliable information.”
The above (and subsequent leading authorities) show that for information to form part of the CGK it is not sufficient that it can be referred to without difficulty but instead must pass the additional hurdle that the information is "generally regarded as sufficiently reliable". The new approach seems to disregard this last hurdle. In addition whilst searching has become easier in the digital age, it is easy to envisage arguments arising over what search would have been conducted by the skilled person. In this case the search conducted was relatively simple and so not a point in issue. Mr Justice Sales concluded these "secondary articles" reinforced his primary conclusion and acted as corroborative evidence that the invention was obvious.
Mr Justice Sales described "tertiary articles" as articles that were "published or available only after the priority date and hence did not form part of the CGK at the relevant time, but which were said to be indicative of what the skilled person would have thought in light of the available literature as at the priority date". He expressed caution over these and stated "the court has to be very careful in assessing a submission like this. Researchers and writers of articles may often have the inventive and imaginative features which are to be excised from the personality of the notional skilled person." He concluded that the tertiary articles did not assist him and did not add anything to what he had already seen.
The interpretation on the scope of CGK given by Mr Justice Sales is surprising, and it will be interesting to see whether it is followed in relation to "secondary articles". Whilst the author of the article disagrees that such breadth should be given to CGK, he does agree CGK is a topic that should be re-visited by the courts in light of technological developments and the ease of access to publications through the internet. If the new approach to CGK as advocated by Mr Justice Sales is followed, it gives those seeking to revoke patents for lack of inventive step greater ammunition to include a whole raft of documents as CGK that would not have been available to them previously.
This case was also fairly unique in that the Judge was compelled to re-write parts of his judgment, something which only happens rarely. Mr Justice Sales' original draft judgment found the patent in suit obvious over CGK alone, something which Teva had not relied on at trial. Instead, Teva's case was based on the 1993 Patent read in the context of the CGK. When this was pointed out by AstraZeneca, Mr Justice Sales was forced to amend his draft judgment. Fortunately for Mr Justice Sales the amendments to the draft judgment mattered not to the overall outcome of the judgment, and he deemed making such amends would not be unfair to AstraZeneca.