Empirical Research Inventions Allowable Generic Claim Scope

In science there is only physics; all the rest is stamp collecting1.

Results! Why, man I have gotten a lot of results. I know several thousand things that won't work2.

We have learned from experience that truth will out. Other experimenters will repeat your experiment and find out whether you were wrong or right. Nature's phenomena will agree or they will disagree with your theory. And although you may gain some temporary fame and excitement, you will not gain a good reputation as a scientist if you haven't tried to be very careful in this kind of work. And it's this type of integrity, this kind of care not to fool yourself that is missing to a large extent in much of the research in cargo cult science3.

Introduction

This discussion is with particular, but not exclusive, reference to practice in the pharmaceutical industry for claiming new chemical entities, and in particular to the feasibility of defining a genus of compounds that validly covers compounds that have not yet been made and tested.

In the early days of the pharmaceutical industry claims were to single compounds. The well-known Felix Hoffmann US patent No 644077 granted in 1900 for aspirin provides an example. Another researcher had previously described acetylsalicylic acid, but Hoffmann demonstrated that the compound that the earlier researcher had made did not possess the correct properties. Hoffmann had developed a new process that gave "the real acetyl salicylic acid" which "exhibits therapeutical properties" and claimed:

"As a new article of manufacture the acetylsalicylic acid having the formula

being when crystallised from dry chloroform in the shape of white glittering needles, easily soluble in benzene, alcohol and glacial acetic acid, difficultly soluble in cold water, being split by hot water into acetic acid and salicylic acid, melting at about 135C, substantially as hereinbefore described."

Compounds isolated from nature and produced synthetically could also be claimed. An example is provided by US patent 3880888 (Firmenich S.A.) which reports the isolation of the compound 3,4,7-trimethyl-2-oxo-1,6-dioxa-spiro[4.5]dec-3-ene from an essential oil derived by distillation of Burley tobacco. The compound is said to provide a mild herbal or woody note to the tobacco, and is claimed as a composition of matter consisting essentially of a compound of the formula

As is well known, the pharmaceutical industry was an offshoot from the dyestuff industry. From the beginning of the 20th century onwards, the practice developed within that industry of claiming classes of dyestuffs generically by means of structural formulae. US-A-1744172 provides an example of so-called Markush practice as it had developed by the mid 1920's. The patentees had claimed a novel class of azo dyes which had the benefit of producing durable colours on cotton and other vegetable fibres, and which are defined in claim 2 of the patent (with slight editing) as follows:

"As new products azo dyestuffs having most probably the general formula:

wherein Y stands for alkyl, oxyalkyl, oxyaryl or halogen; X represents either the sulfone group SO2 or the carbonyl group CO, and R1 represents ... alkyl, aryl, aralkyl ... which are in the dry state reddish to dark coloured powders, soluble in concentrated sulphuric acid with from blue to dark violet colours ... and which when produced on vegetable fibres yield reddish shades of excellent fastness to kier boiling."

The patentability of the compounds of this genus flows from the link between the chemical structure and the newly discovered and valuable properties possessed by the compounds of that structure. That formulation is consistent with the question put forward by Sir Stafford Cripps K.C. in UK proceedings between Sharp & Doehme v Boots4 which concerned the manufacture of certain alkyl-substituted resorcinols which were known as antiseptics (at that time chemical product claims were not allowed in the UK). Published papers had already disclosed that the C1-C4 members of the class had been made and that antiseptic activity increased as the number of carbon atoms in the alkyl chain increased. The patentees averred that because drug research was empirical, the skilled person knew in advance neither that the higher alkyl resorcinols could be produced by the claimed method nor what their antiseptic properties would be. The compound that proved to be of therapeutic value was n-hexyl resorcinol which is of formula:

The defendants replied that because therapeutic activity increased in the known compounds from C1 to C4, it was obvious to make the higher members of the series. Sir Stafford Cripps argued that the question concerning inventive step that the court had to decide was based on whether there was an obvious link between structure and value, and was as follows:

"Was it for practical purposes obvious

to any skilled chemist

in the state of chemical knowledge existing at the date of the patent, which consisted of

the chemical literature available, a selection of which appeared in the Particulars of Objections, and

his general chemical knowledge,

that he could make valuable therapeutic agents by making the higher alkyl resorcinols?" (Paragraphing and emphasis added).

The same link between structure and value is implicit in the requirement for utility in US law, as is apparent, for example, from the following passage from Brenner v Mason which calls for the product to be useful, i.e. to have a "specific benefit":

"Until the process claim has been reduced to production of a product shown to be useful, the metes and bounds of that monopoly are not capable of precise delineation. It may engross a vast, unknown, and perhaps unknowable area. Such a patent may confer power to block off whole areas of scientific development, without compensating benefit to the public. The basic quid pro quo contemplated by the Constitution and the Congress for granting a patent monopoly is the benefit derived by the public from an invention with substantial utility. Unless and until a process is refined and developed to this point - where specific benefitexists in currently available form - there is insufficient justification for permitting an applicant to engross what may prove to be a broad field."

In the azo dyestuff case referred to above, it is clearly credible that the whole class of compounds would dye cotton with the indicated combination of colour and resistance to boiling. However, the credibility of similar Markush claims for pharmaceuticals or agrochemicals is open to question since human, animal and living plant cells are more complex than cotton fibres.

Generic claims to the results of empirical research

Finding pharmaceutically active compounds has been at least until recently a task of empirical research of the kind pioneered by Thomas Alva Edison, and the rules applicable to patents of this category have been known at least since the decision of the US Supreme Court in the Incandescent Lamp case which concerned a third party patent which was alleged to be infringed by the electric lamps being made and sold by Edison licensees. The third party patent purported to monopolise all carbonised fibrous or textile materials for use as filaments for electric lamps, as is apparent from the following main claim:

"An incandescing conductor for an electric lamp, of carbonized fibrous or textile material, and of an arch or horseshoe shape, substantially as hereinbefore set forth."

The evidence adduced in the case showed that the researches carried out by the third party could not support such a broad monopoly and that the field was unpredictable. The factual background and the reasoning of the court will be apparent from the following passages from the Opinion:

"Is the complainant entitled to a monopoly of all fibrous and textile materials for incandescent conductors? If the patentees had discovered in fibrous and textile substances a quality common to them all, or to them generally, as distinguishing them from other materials, such as minerals, etc., and such quality or characteristic adapted them peculiarly to incandescent conductors, such claim might not be too broad. If, for instance, minerals or porcelains had always been used for a particular purpose, and a person should take out a patent for a similar article of wood, and woods generally were adapted to that purpose, the claim might not be too broad, though defendant used wood of a different kind from that of the patentee. But if woods generally were not adapted to the purpose, and yet the patentee had discovered a wood possessing certain qualities, which gave it a peculiar fitness for such purpose, it would not constitute an infringement for another to discover and use a different kind of wood, which was found to contain similar or superior qualities.

The present case is an apt illustration of this principle. Sawyer and Man supposed they had discovered in carbonized paper the best material for an incandescent conductor. Instead of confining themselves to carbonized paper, as they might properly have done, and in fact did in their third claim, they made a broad claim for every fibrous or textile material, when in fact an examination of over 6,000 vegetable growths showed that none of them possessed the peculiar qualities that fitted them for that purpose. Was everybody, then, precluded by this broad claim from making further investigation? We think not.

The injustice of so holding is manifest in view of the experiments made, and continued for several months, by Mr. Edison and his assistants, among the different species of vegetable growth, for the purpose of ascertaining the one best adapted to an incandescent conductor. Of these he found suitable for his purpose only about three species of bamboo, one species of cane from the valley of the Amazon (impossible to be procured in quantities on account of the climate), and one or two species of fibers from the agave family...