Drug Patents Under the Spotlight. Sharing practical knowledge about pharmaceutical patents
(2003; 40 pages) View the PDF document
Table of Contents
View the document1. Introduction
Open this folder and view contents2. Four key concepts to understanding drug patents
Close this folder3. The patent system should respond to countries' public interest
View the document3.1. The subject matter of a patent must be new
View the document3.2. The subject matter of a patent must be inventive
View the document3.3. Patentability is a matter of national policy: example of new use inventions
View the document3.4. The invention should be clearly disclosed to benefit society as a whole
View the document3.5. An invalid patent may be revoked
View the document4. How to read and use the patent table
View the document5. Conclusions
View the document6. References
View the documentAnnex A - Patent Table
View the documentAnnex B - The anatomy of a patent

3.2. The subject matter of a patent must be inventive

It is not enough for a patentable invention just to be new. In exchange for 20 years of monopoly rights, the inventor should have to give something very valuable to the public. Accordingly, the second fundamental requirement for a valid patent is that the invention involves an inventive step. But working out a technical definition of inventive step is much harder than defining novelty. Whether or not an invention is novel can be determined on the basis of relatively clear-cut tests; whether or not an invention is obvious is much more a matter of opinion.

An illustrative approach to defining inventive step is that taken by the European Patent Office (EPO) applying the European Patent Convention (EPC). EPC Article 56 provides that "an invention shall be considered as involving an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art"[37].

Who or what is a person skilled in the art, though?[38] According to common practice, this person is to be viewed as an ordinary researcher in the field. (S)he will be regarded as having all the "standard" knowledge available in the field and having the "standard" capabilities for "routine work and experimentation"[39] allowing straightforward progress from what is already known. The key thing that a patent application should therefore demonstrate is a step forward which such a person couldn't have thought of: the invention should require an inventive step which would not have been obvious to him/her.

When considering how to judge the inventive step, a patent examiner has to review the documents (e.g. scientific or technological literature including other patent documents) which show the state of the art. The examiner then has to decide whether or not the invention described in the patent application is obvious regarding what is demonstrated in the documents. Patent examiners, in other words, have to put themselves in the position of this person skilled in the art to make the necessary judgement. This is one of the reasons why patent examiners should have scientific or technological qualifications. Whether or not an examiner has made the right judgement is the most frequently raised question in disputes about patent validity.

A good indicator to demonstrate an inventive invention is whether it produces some surprising or unexpected effect[40]. Imagine two drugs, one that makes people 5cm taller and one that makes them 5cm thinner. If a patient took the two together and got 5cm taller and 5cm thinner, that is just what you might have expected and the combination of the two cannot be said to be an invention. But if a patient took the two together and became completely resistant to malaria instead, this would be a surprising "synergistic" effect and the combination of the two could be a new and separate invention. A practical example of what is claimed to be an unexpected effect is given on stavudine in Annex B.

How surprising (or non-obvious) the invention has to be before a patent is granted in each country should depend on the practice of each patent office, following the rules decided in each country, which can of course vary over time as well. An invention may be regarded as being obvious in some countries, but it may be regarded as surprising in others. So, setting the level of inventive step required is another important choice open to every WTO member. The current low standard of inventiveness applied in developed countries has resulted in a "proliferation of patents for trivial inventions which may not contribute to the over-riding objective of the patent system which is the advancement of science for public benefit."[41]

Photo: © Christian Schwetz

Each country can decide for itself what sort of rules it designs to test inventiveness, although this may not be easy. An example of four inventions follows on the next page. There are presumably good reasons why each of the patent offices mentioned decided to grant the patents. Perhaps there has been a full and frank debate in each of the countries about what the most suitable inventive step level to choose is. Perhaps there has not. It is known that the African Intellectual Property Organization (OAPI) and the South African patent office do not carry out a full examination of a patent application before a patent is granted (see p. 18), so it can be no surprise that patents are granted there with wide protective scope although the equivalents in e.g. EPO are cut down to size (or rejected, see the patent table). Unless the patents are challenged and cut down to size or revoked, people living in the OAPI region and South Africa will very likely frequently be living under broader patents than people in Europe, for example.

How inventive are "combination" and "formulation" inventions?

Combination therapies are a vital tool in the fight against HIV/AIDS and many other diseases. It is well known that if a single medicine is used against an infectious agent, the agent may become resistant to that medicine. One way of reducing this likelihood is to use more than one drug at once since it is less probable that the agent will develop resistance to both attacks simultaneously. Antiretroviral (ARV) treatment is a good example of this, triple therapy now being the recommended approach. The best possible way to deliver these combination therapies is in a single pill to increase compliance and reduce resistance.

A leading example of a fixed dose combination (FDC) medicine combining two known ARVs is Combivir®, the trade name given by GlaxoSmithKline (GSK) to their combination of zidovudine (AZT) and lamivudine (3TC). An example of an FDC combining three known ARVs is Trizivir®, the trade name given by GSK to their combination of AZT, 3TC and abacavir. In this case, GSK also happens to own the patents for the compounds AZT, 3TC and abacavir. If you look at the patent table in Annex A, you will see that GSK has obtained patents widely for both Combivir® and Trizivir®, and has filed for or obtained patents for a particular formulation of these drugs. In order to be able to obtain valid patents to protect each of these inventions, GSK should have demonstrated (or should be able to demonstrate) that the combinations and formulations involved are not obvious.

GSK first filed a patent application back in 1991 to protect the broad "idea" of using AZT and 3TC in combination. The patent application states that using the two drugs together has a surprising effect in that e.g. the emergence of resistance is reduced. Patents were granted quickly in OAPI and South Africa. Later on a patent was granted by EPO but was quickly opposed by Novartis. This opposition was partially successful and the scope of the GSK patent was reduced.

GSK then filed another patent application in 1995 to protect the broad idea of using AZT, 3TC and abacavir in combination. The patent application says that using the three drugs together has a surprising effect in that e.g. the emergence of resistance is reduced. Such patents have been granted in e.g. EPO and ARIPO.

GSK then filed a patent application in 1996 to protect the combination of AZT and 3TC in a tablet formulation (AZT, 3TC and a non-active ingredient, a glidant). A patent for this invention has been granted by OAPI, ARIPO and South Africa but is still under examination by EPO. It is important to follow up what happens in EPO and compare that with the patents already granted elsewhere.

GSK then filed a patent application in 1998 to protect the combination of AZT, 3TC and abacavir in a tablet formulation (this time AZT, 3TC, abacavir and a glidant). None of the patent offices in the table have apparently yet granted any patents for this invention.

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