Status of the Insufficiency/Obviousness Squeeze - An appraisal of the House of Lords’ Generics et al v Lundbeck Judgments


This article was first published in The World Intellectual Property Report May 2009.

Summary of Generics UK, Arrow and Teva v Lundbeck (“Lundbeck”)

In February 2009 the House of Lords unanimously dismissed an appeal by a number of pharmaceutical companies against the Court of Appeal’s decision to not revoke Lundbeck’s escitalopram patent on grounds of insufficiency. The effect of the judgment was that Lundbeck’s patent protecting escitalopram, an enantiomer of an anti-depressant called citalopram, was upheld as sufficiently disclosing the product.  This was so even though only two methods of making escitalopram were detailed in the specification, and despite the fact that the enantiomer previously known to be present in a racemate and was expected to be responsible for the activity of the racemate,  and that inventive step only lay in the method of producing the enantiomer. The various speeches in the House of Lords separated the concepts of novelty, obviousness and sufficiency and their approach was to look at each one of the issues separately. There are a number of ways in which this clarification of the correct approach may impact patent invalidity claims and a number of further questions to be answered.


In 1996 the House of Lords handed down its opinion in Biogen Inc v Medeva plc [1997] RPC 1. The patent in Biogen related to a product-by-process claim covering a class of products, but only one process for producing one of the products was described in the patent specification. Lord Hoffmann giving the leading speech, considered whether and to what extent a claim to more than one product or process was sufficient, stating that:

“…if the claims include a number of discrete methods or products, the patentee must enable the invention to be performed in respect of each of them”.

Lord Hoffmann later went on to state:

“the extent of the monopoly claimed [should not] exceed … the technical contribution to the art made by the invention as described in the specification”.

At paragraph 71 of the judgment, citing the T-0292/85 Genentech I/Polypeptide expression decision of the Technical Boards of Appeal of the EPO, Lord Hoffmann stated that there are two ways in which the breadth of a patent claim may exceed its technical contribution to the art embodied in the invention:

  1. “The patent may claim results which it does not enable, such as making a wide class of products when it enables only one of those products and discloses no principle which would enable others to made”

  2. “or it may claim every way of achieving a result when it enables only one way and it is possible to envisage other ways of achieving that result which makes no use of the invention”.

Over time these became known in the English courts as "Biogen insufficiency". The decision in Biogen made clear that for a claim to a class of products or processes to be valid the skilled person must be enabled by the description in the patent to make or perform the invention to the full breadth of the claim. The claim to a class of products-by-process was not sufficiently supported by a specification that did not describe the process to produce certain products in the class that were claimed. Hence, the Biogen patent was held insufficient. What was not clear however, as we now know, was the extent to which the principles laid down in Biogen applied to a claim for a product that was known to exist but had not yet been made.

Facts in Lundbeck

In 1979 Lundbeck’s patent for what was to become the antidepressant drug, citalopram was published. Citalopram is a racemic mixture comprising of 2 mirror-image enantiomers, commonly labelled (-) and (+).  By 1987, and with, at least on the evidence in the English case, difficulty, Lundbeck had developed a method to isolate the therapeutically more effective (+) enantiomer of citalopram, escitalopram . Therefore, Lundbeck applied for and was granted a patent containing product claims to the (+) enantiomer,  to a pharmaceutical composition containing the enantiomer and a process claim for the method for producing the enantiomer.

The (+) enantiomer was self-evidently a component of the citalopram racemate, although it was not specifically described in the citalopram patent.  It was held at first instance that this enantiomer would have been expected, by analogy with other such compounds, to be responsible for the activity of the racemate. Accordingly, any invention in the escitalopram patent had to lie in the method of isolating or producing it from the racemate. Two methods of producing escitalopram were disclosed in the escitalopram patent specification, but it could have been envisaged, as proved to be the case, that others would be discovered in the future.

Novelty and obviousness at first instance and on appeal

The appellants initially attacked the product claims on grounds of lack of novelty, obviousness and insufficiency and also attacked the process claim on the ground of obviousness. The attacks of novelty and obviousness failed both at first instance and in the Court of Appeal. On novelty, applying the House of Lords decision in Synthon v SmithKline Beecham [2005] UKHL 59, the courts found that there had previously been no disclosure enabling an ordinary skilled person to make escitalopram. On obviousness, although the desire to make escitalopram clearly existed, the method of doing so involved a non-obvious and therefore inventive step. Escitalopram was therefore novel and inventive.

Novelty in the House of Lords

Although novelty was not in issue in the House of Lords in Lundbeck, Lord Scott did still discuss it, making reference to EPO case law, which in T-0296/87 Hoechst/Enantiomers had held that, even though the existence of enantiomers may be self-evident from inspection of the chemical structure of the racemate of a compound, their novelty is not destroyed by the mere disclosure of the structure of the racemate in which they are contained because this does not disclose them in individualised form.  The situation is different if the state of the art specifically identifies the enantiomers, and moreover enables their production. In Merrell Dow Pharmaceuticals Inc v H N Norton & Co Ltd [1996] RPC 76, an active ingredient, which was a metabolite of and therefore different to the drug that the prior art taught to be taken by patients, was held to form part of the state of the art by virtue of its production as a result of liver metabolism in their bodies. Therefore, it could be said that in Lundbeck, the effect of escitalopram on the brain of patients was the result of providing the racemate, citalopram, to them, suggesting that the Merrell Dow ratio is, like Biogen, a principle that it not applicable to differing but similar fact patterns.

Insufficiency at first instance

Although subsequently reversed in the Court of Appeal, the insufficiency challenge succeeded at first instance with Kitchen J applying his interpretation of the principle from Biogen to hold that patent protection should only be afforded to products that it was obvious to seek to make to the extent that the method for their preparation is disclosed in the patent. He said that:

“The first person to find a way of achieving an obviously desirable goal is not permitted to monopolise every other way of doing so”.

Kitchen J treated the “technical contribution to the art” as being identical to the inventive step, which in this case was the method of isolating the (+) enantiomer. He then held that any claim to the product that was not further restricted to this specific inventive step, was insufficient. Thus he held the product claims invalid and only upheld the validity of the claim to the disclosed processes.

Insufficiency in the Court of Appeal

The correct position, which was approved in the House of Lords, was initially stated by Lord Hoffmann, who was on this occasion sitting in the Court of Appeal. Even if a product’s existence and utility may have been known, once the product satisfies the requirements of novelty and inventive step, the “technical contribution to the art” is the product itself and not the process by which it was made, even if that process was the only inventive step. Lord Hoffmann believed that the Patents Act 1977 clearly stated that all that was required for a product claim to be sufficient was that, the skilled person, on reading the patent specification would be able to make the product, stating:

“In the case of a product claim, performing the invention for the purposes of section 72(1)(c) means making or otherwise obtaining the product. In the case of a process claim, it means working the process. A product claim is therefore sufficiently enabled if the specification discloses how to make it. There is nothing to say that it must disclose more than one way”.

Lord Hoffmann referred to the established principle that if the invention is a way of making a new and non-obvious compound, one disclosed method is enough to render the patent sufficient. He went on to explain that Kitchen J’s finding had the effect of making the requirements of sufficiency differ according to the nature of the inventive step. Kitchen J’s judgment stated if the invention is a way of making an obvious compound, one disclosed method will not suffice. In Lord Hoffmann’s opinion, there is nothing in the relevant section of the Patents Act which connects the requirements of sufficiency to inventive step.

Jacob LJ added that it was not necessary for the patent specification to cover all uses of a product or ways of producing a product. He stated that the concept that “the patentee should not have more then he deserves” does not form part of the statutory test for insufficiency. Jacob LJ simplified the test by stripping it down to its bare bones; it was a straightforward answer to the straightforward question: “Does the patent enable the skilled man to make it?” In this case the answer is “yes”.  He then went on to explain that whether that simple test led to the patentee being, in practice, permitted to protect more than he has invented or “deserves” is not relevant.  However Lord Justice Jacob emphasised the difference in this context between a claim to a single product and one to a class of products when he went on to say at paragraph 61:

“So, for example, if a man finds a particular way of making a new substance which is 10 times harder than diamond, he cannot just claim "a substance which is 10 times harder than diamond." He can claim his particular method and he can claim the actual new substance produced by his method, either by specifying its composition and structure or, if that cannot be done, by reference to the method (see Kirin-Amgen at [90-91]) but no more. The reason he cannot claim more is that he has not enabled more – he has claimed the entire class of products which have the known desirable properties yet he has only enabled one member of that class. Such a case is to be contrasted with the present where the desirable end is indeed fully enabled – that which makes it desirable forms no part of the claim limitation.”

Insufficiency in the House of Lords

Surprisingly, in light of Lord Hoffmann giving judgment in the Court of Appeal, the House of Lords agreed to hear a further appeal by the Claimants, and on doing so unanimously dismissed it. Their Lordships’ reasons were very much in line with those of Lord Hoffmann in the Court of Appeal; however, certain principles were further explored particularly by Lords Walker, Mance and Neuberger.

Lord Walker elaborated on the argument before the House as to whether the “inventive concept” (which is often regarded as the relevant term for what must be disclosed for obviousness) means the same as the “technical contribution to the art” (which is often used as the relevant term to assess insufficiency). He stated that neither expression is a statutory term and that both had been used by Lord Hoffmann in his Biogen judgment. Lord Walker recognised that the two expressions are “certainly connected”, but he did not see it as helpful to treat them as having precisely the same meaning. At paragraph 30 he described the difference as:

“‘Inventive concept’ is concerned with the identification of the core of the invention – the idea or principle, of more or less general application which entitles the inventor’s achievement to be called inventive. The invention’s technical contribution to the art is concerned with the evaluation of the inventive concept – how far forward has it carried the state of the art? The inventive concept and the technical contribution may command equal respect but that will not always be the case.”

Lord Neuberger recognised that although technical contribution is an extra-statutory concept, at least as a general rule, the monopoly to be granted to the patentee is to be assessed by reference to the “technical contribution” made by the teaching of the patent. Applying this to the escitalopram patent he said that it was clear that the technical contribution made by the patent was to make available, for the first time, a product that had previously been unavailable. On that basis it followed that Lundbeck were entitled to claim the (+) enantiomer. Later in his judgment, Lord Neuberger referred to Lord Hoffman’s comments in Biogen:
“the extent of the monopoly claimed [should not] exceed … the technical contribution to the art made by the invention as described in the specification”.

Lord Neuberger then drew out the principle that in the context of the simple product claim the technical contribution is the product itself. He suggested that:

“the technical contribution can often be equated with non-obvious novelty – what is new to the art and not obvious is really another way of identifying the technical contribution”.

He continued to explain why he thought Kitchin J had been mistaken in the application of Biogen, saying that he thought it was attributable to “the focussing by Lord Hoffman in Biogen on the “inventive step”:

“There is a difference between the “inventive step” or “inventive concept”, on the one hand, and the “technical contribution to the art”, on the other hand. I respectfully agree with the explanation of the difference between the two concepts given [by] Lord Walker’s opinion. When considering the validity of a simple product claim … it may be that concentrating on the identification of the inventive step rather than the technical contribution can lead to error. “Inventive step” suggests how something has been done, and , in the case of a product claim at any rate, one is primarily concerned with what has been allegedly invented, not how it has been done. On the other hand where the claim is for a process or … includes a process, the issue of how the alleged invention has been achieved seems to be more in point.”

Therefore, it seems that Lord Neuberger was in agreement that it is the “inventive concept” or “inventive step” that is required to be fully disclosed in the patent specification for the patent to be non-obvious. The “technical contribution to the art” on the other hand is more relevant as a marker as to what the judgment on questions of insufficiency should be based. This means that obviousness and insufficiency are, in effect, determined by reference to different aspects of the patent.

Inventive Concept and Technical Contribution
The technical contribution can (in the words of Lord Neuberger) “often be equated with non-obvious novelty”, the basis for which is found in the specification. In contrast the inventive concept is assessed by looking at the claim as is discussed by Jacob LJ in Unilever v Chefaro [1994] RPC 567 and  Pozzoli Spa v BDMO SA & Anor [2007] EWCA Civ 588).

“It is the inventive concept of the claim in question which must be considered, not some generalised concept to be derived from the specification as a whole. Different claims can, and generally will, have different inventive concepts. The first stage of identification of the concept is likely to be a question of construction: what does the claim mean? It might be thought there is no second stage – the concept is what the claim covers and that is that. But that is too wooden and not what courts, applying Windsurfing stage one, have done. It is too wooden because if one merely construes the claim one does not distinguish between portions which matter and portions which, although limitations on the ambit of the claim, do not. One is trying to identify the essence of the claim in this exercise.”

Following Lundbeck it appears that the technical contribution and inventive concept can be different in nature depending on the type of claim under consideration.
In respect of claims to a single product (which for the purposes of this analysis also includes product-by-process claims ), the technical contribution is the product itself. The product is inventive as long as the actual way of producing the product was not obvious, whether or not there was a desire to produce the product. The inventive concept in this particular situation is the method of making the product. Where the identity of the product and its utility could not have been predicted the inventive concept may subsist in the product and possibly also the method of making the product.
Several cases have dealt with the different situation of claims to a class of products (this type of claim includes class of product-by process claims, such as that in issue in Biogen).  In Schering Plough v Norbrook Laboratories Ltd [2005] EWHC 2532 where the claim covered combinations of two classes of compounds, Floyd J held that not all the combinations of the compounds would work in the manner claimed and accordingly the patent was not sufficient across the entire class of products. Pharmacia Corporation and ors v Merck [2001] EWCA Civ 1610 concerned a patent in which numerous products were claimed which were said to have anti-inflammatory action characterised by their particular mode of action. It was shown by experimentation that many such compounds lacked the required characteristics and one could not provide a general description of a class having the desired characteristics.  Where the claim is for a class of products where those products and their utility could not have been predicted, the technical contribution is the class of products itself and the inventive concept in these cases is not just limited to the process of producing the class of products, but instead extends to such class of products and its utility.
With respect to product by process claims and process claims both the technical contribution and the inventive concept are the process as claimed.

Types of insufficiency

A number of different “types” of insufficiency appear to have evolved, all of which are based upon the same overarching principle in the UK Patents Act 1977 at section 72(1)(c).
“Classic” insufficiency

Classic insufficiency refers to the simple situation whereby the specification does not enable the person skilled in the art to achieve the technical contribution of the invention at all or without undue burden. This is relevant for all types of claim, including those to a single product.

A related type of insufficiency is the situation where the person skilled in the art cannot determine whether the alleged infringing product falls within the claim, such as set out in Kimberley-Clark Worldwide Inc v Procter & Gamble Limited [2000] EWHC 74 (Pat) . In these situations, it could be said that the technical contribution cannot accurately be determined and therefore achieved. This type of insufficiency (though not strictly “Classic”) is similar enough to classic insufficiency not to be considered separately in this article.

Class of products insufficiency

This type of insufficiency is relevant to claims for a class of products. For product claims, where the product is unknown to the art, the technical contribution to the art is the product itself.  If the patent only enables some of the class of products claimed to be produced, or if only some of the class of products have the promised utility (see Schering Plough v Norbrook, and Pharmacia v Merck, supra) then the patent will only be sufficient in respect of these products. Again, where the products and their utility have been foreseen, the inventive concept with respect to those products is the process of producing the products, but where the class of products are not foreseen, the inventive concept will be the products themselves.

“Biogen” insufficiency

Following the reasoning and judgment in Lundbeck it is now clear that Biogen insufficiency, if indeed it constitutes a separate type of insufficiency from “class of products” insufficiency, can only exist for claims for a class of products as defined by a class of processes for making them (a form of product-by-process claim).  If the patent claims a number of ways of getting to a class of products, but only describes a subset of those methods enabling a subset of those products, then the patent is insufficient. Here, the technical contribution to the art is the processes that are enabled by the patent, and, therefore only those claims for those processes that are enabled are valid. If the product is foreseen, the inventive concept is also this process, but if the product is not foreseen, the inventive concept will be the product itself.

Class of processes insufficiency

For process claims and class of processes claims, the technical contribution and the inventive concept is the process itself.  If a patent only enables one of the class of processes claimed to be performed there is an insufficiency. Therefore, only the claims for those processes that are enabled are valid.

The impact of Lundbeck on use of an insufficiency squeeze
It is a common and orthodox tactic in patent litigation to attempt to place the patentee in a squeeze, such as the obviousness/insufficiency squeeze.  In operation of the obviousness/insufficiency squeeze it is argued that either i) the specification of the patent does not enable the technical contribution to be worked by the person skilled in the art; or ii) if it does, only as a result of taking the common general knowledge into consideration, the technical contribution to the art is purely common general knowledge and therefore the patent is obvious.

Although Lundbeck was not a case in which any insufficiency/obviousness squeeze was used, it appears on the face of the House of Lords judgment and, in particular, the comments of the three Law Lords who gave substantive opinions, that Lundbeck may have an impact on the situation in which such squeezes can be run.  The basis for drawing such conclusion is that their Lordships are clear that in their opinion there may be, in particular cases, a difference between the technical contribution to the art and the inventive concept.  The difference between these two concepts, however, only appears in limited circumstances and appears to be dependent on the type of claim at issue.

Therefore, in respect of certain types of product and product-by-process claims the inventive concept and technical contribution are not the same.  Accordingly, the same basis does not exist to assess obviousness and insufficiency and therefore the squeeze described above is not possible.  The error at first instance in Lundbeck lay in treating product claims as if they were process claims and considering that the technical contribution and inventive concept must always be the same for product claims.