This article discusses the inherent difficulties in patent interpretation as the biotechnology industry gathers momentum globally.
The recent years have seen a marked surge in biotechnology related inventions in the United States, Europe (particularly the United Kingdom) and Japan. China and India have also been internationally noted for their innovations
in the biotechnology industry. At the same time, there is a growing global acceptance that biotechnology is able to provide the remedy for various diseases, which, to-date, remain untreatable; or improve the quality of existing
therapeutic remedies.
This has triggered various pharmaceutical giants to invest heavily in biomedical research. In order to ensure due and prompt monetary returns from these investments, the investors ensure that the inventions are protected from
unlawful copying by their competitors. Such protection usually entails the filing of patents as soon as the inventions are made.
Patent Claims
However, in order to satisfy the statutory prerequisites of the grant of a patent, a sufficient and clear disclosure of the invention has to be made in the application for the patent, such that a person skilled in the art will
be able to perform the invention, based on the disclosure.
The disclosure consists of two parts:
As such, the wording of the claims is crucial.
However, the haste with which inventions are sought to be protected often results in inherent difficulty in the construction of the claims. Often, the claims may not have been sufficiently and clearly described. Added to this
difficulty is the fact that as inventions are novel, standard words or phraseologies do not exist yet to describe the inventions in the most effective manner.
The above difficulties are further exacerbated when competing biotechnology products exhibit their potentially infringing similarities only in vivos, that is, upon reaction with the natural chemicals of the body.
In summary, it is not easy to capture the essence of an invention in a verbal or written description. The language in patent claims that purport to describe the inventions may not capture every nuance of the inventions, or
describe with complete precision, the range of its novelty.
Interpretation of Patent Claims
Thus, a strict literal interpretation of a patent claim poses the risk of allowing one to copy the patent without any infringement by adding unimportant and insubstantial substitutes for certain elements of the invention as
claimed in the patent. In other words, a strict literal interpretation could result in diminishing the value of a patent.
As such, the courts in the US apply what is known as the ‘doctrine of equivalents’ when interpreting patent claims. Under this doctrine, a patent claim will be imputed an interpretation that would embrace all equivalents to the
claim.
The Singapore courts follow the ‘purposive approach’ that was enunciated by the English court in the case Catnic Components Ltd v Hill and Smith [1982] RPC 183. This approach entails the examination of the purpose
underlying the integers in an invention, rather than applying a literal approach to interpreting the claims of a patent.
Therefore, in a patent infringement dispute, courts generally tend to engage some degree of flexibility when interpreting a patent claim. In so doing, the courts generally adopt an approach that gives the patent claim a wider
meaning than its strict literal interpretation. While the details of the approach taken may vary from jurisdiction to jurisdiction, the concepts are similar, be it in the US, UK or Singapore.
However, such an approach is not without its consequential difficulties. In particular, it fudges the distinctiveness of the scope of the claim. In the result, competitors may be unable to discern for themselves as to what may
constitute an infringement of a patent or a lawful alternative to a patented invention.
Consequently, competitors may be thwarted from engaging in legitimate manufactures outside the limits of a patent, or they may invest by mistake in competing products that the patent secures. This, in turn, is likely to lead to
wasteful litigation between competitors.
The US courts have acknowledged this uncertainty, but regard it as an inevitable price for ensuring the appropriate incentives for innovation.
The ‘Doctrine of Equivalents’ in the United States
The origin of the doctrine of equivalents dates as far back as 1853, and was revisited by the US Supreme Court in 1950 in the landmark case, Graver Tank & Mfg Co v Linde Air Products Co 339 US 605; 85 USPQ 328 (1950),
where the purpose of the doctrine was described in a nutshell as to prevent the practice of ‘a fraud on a patent’.
The dispute in Graver Tank involved the distinction between a patented welding flux that was specified in the claim as an ‘alkaline earth metal silicate’, and the accused flux, which contained manganese silicate. As such, there was no literal infringement between the two metals.
Notwithstanding the above distinction, which is based on a literal interpretation, the US Supreme Court in Graver Tank upheld a finding that manganese was equivalent to magnesium for the purposes of the patent claim.
Accordingly, the court affirmed a judgment of infringement under the doctrine of equivalents.
In applying the doctrine, the test that was applied by the court was to ask whether the offending substance performed ‘substantially the same function in substantially the same way to obtain the same result’. This test has
since been traditionally known as the ‘triple-identity’ test or the ‘function/way/result’ test.
The proper time for evaluating equivalency and knowledge of interchangeability is at the time of infringement, and not at the time of issuance of the patent, as was ruled by the US Supreme Court in a more recent case, namely,
Warner-Jenkinson Co v Hilton Davis Chemical Co 520 US 17; 41 USPQ 2D 1865 (1997).
The ‘Doctrine of Equivalents’ in Biotechnology Patents
While the application of the doctrine of equivalents is not confined to biotechnology patents, its application to biotechnology patents is likely to exacerbate the uncertainty and unpredictability of biotechnology patents, for
the reasons mentioned earlier.
The case of Genentech, Inc v Wellcome Foundation Ltd, 29 F 3d 1555; 31 USPQ2d (Fed Cir, 1994), provides a succinct illustration of the complexities involved in
the application of the doctrine to biotechnology patents.
The issue in this case was whether Wellcome’s tissue plasminogen activator (‘t-PA’) analog, known as FE1X, infringed any of three Genentech patents under the doctrine of equivalents.
The three patents in issue covered: (a) t-PA purified from natural sources (‘603 patent); (b) DNA encoding recombinant t-PA (‘075 patent); and (c) processes for making recombinant t-PA (‘330 patent). In essence, the case turned
on how broadly the ‘function’ was defined in the ‘function/way/result’ test for infringement under the doctrine of equivalents.
In its analysis for the purpose of the doctrine of equivalents, the court found that the specific activity of FE1X was outside the permissible range of equivalents of the ‘603 claims.
As for the ‘075 and ‘330 patents, which did not contain a specific activity limitation, the court observed that the doctrine of equivalents analysis would be highly dependent on how broadly the ‘function’ of t-PA was defined.
On this point, the court adopted the principle that was enunciated in Zenith Laboratories, Inc v Bristol-Myers Squibb Co 31 USPQ2d 1170:
The operative definition for purposes of equivalency analysis is the intended function as seen in the context of the patent, the prosecution history (see below), and the prior art. [parenthesis added]
In applying the above principle, the court in Wellcome focused on the fibrin binding affinity of human t-PA:
The fibrin binding affinity of human t-PA is a critical distinction between this protein and the two prior plasminogen activators, urokinase and streptokinase. Thus, a functional definition of t-PA, which ignores this distinction, would result in a range of equivalents which impermissibly reads on the prior art.
In the other US case referred to above, Zenith Laboratories v Bristol-Myers Squibb Co 19 F 3d 1418; 30 USPQ 2d (Fed Cir, 1994), the competing products involved a particular crystalline form of the antibiotic cefadroxil, known
as Bouzard monohydrate, and a different crystalline form of cefadroxil (cefadroxil DC), ie a hemihydrate form, which, reportedly, is converted into Bouzard crystals in a patient’s stomach.
The Federal Circuit made a finding that cefadroxil DC did not perform the same function, in the same way, to obtain the same result, as Bouzard crystals. Therefore, there were no equivalents under the triple-identity test.
In another case, Glaxo Wellcome, Inc v Pharmadyne Corp 32 F Supp 265 (D, Md, 1998), the district court found infringement under the doctrine of equivalents, where Glaxo’s pharmaceutical composition claim recited the inclusion
of an effective amount of ethanol, and the accused product by Pharmadyne contained propylene glycol instead.
Glaxo argued, amongst others, that persons skilled in the art knew that propylene glycol was interchangeable with ethanol in pharmaceutical formulations. Thus, the accused product was nothing more than a copy of the patented
composition.
The district court held that Pharmadyne’s ethanol-free, propylene glycol formulation infringed under the doctrine of equivalents.
Critics have, however, commented that Glaxo could have actually drafted their patent claims differently such as to cover a defined genus of short chain alcohols or polyols, instead of the specific compound, ‘ethanol’.
Therefore, when Glaxo had failed to describe in their claim what was describable, Glaxo should not have been accorded the benefit of the doctrine of equivalents.
Prosecution History
Prosecution history (as referred to in the Zenith Laboratories case mentioned above), or the principle derived therefrom, namely, the prosecution history estoppel, has been the subject of a very important recent decision of the
US Supreme Court, namely, Festo Corp v Shoketsu Kinzoku Kogyo Kabushiki Co Ltd No 00-1543, (argued on 8 January 2002, and decided on 28 May 2002), in conjunction with the doctrine of equivalents.
The Supreme Court in Festo reiterated that, where an original claim has been rejected by the Patents Office, the decision of the patentee to submit an amended but narrowed claim, is a concession that the invention as patented
does not reach as far as the original claim.
As such, the patentee is estopped from establishing any unforeseen equivalent to the surrendered territory of his amended claim, in the interpretation thereof.
The Supreme Court, however, went on to clarify that the above ruling does not mean that the amended claim is so perfect in its description that no one could devise an equivalent to the amended claim.
The doctrine may still apply to the amended claim provided the patentee is able to show that at the time of the amendment, one skilled in the art could not reasonably be expected to have drafted a claim that would have
literally encompassed an alleged equivalent.
To conclude, the effect of the prosecution history estoppel is to rebut an inference that a matter that was not described in the patent was not indescribable.
Conclusion
As in all arts, but more imminently in biotechnology, the doctrine of equivalents or any such similar principle poses much uncertainty and unpredictability in the interpretation of patent claims.
In the circumstances, a copier of a biotechnology product would rarely know in advance whether his product infringes a patent or not. The only occasion when he is able to know the true position is when a court makes a finding
on the issue. Unfortunately, this uncertainty is not just confined to a copier, but would also be experienced by any good faith competitor.
Hence, unlike other types of commercial disputes, patent litigation is one which even some courts acknowledge as an inevitable instrument that is necessary for the promotion of the progress of scientific discoveries.
AJ Ramachandran
Rajah & Tann