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

3.5. An invalid patent may be revoked

As outlined above, the granting of a patent is far from being a final act: a granted patent may be partly or completely invalid.

When a patent constitutes a barrier to access to essential medicines, it is important to investigate whether the patent is indeed valid (and infringed) before entering into negotiations with the patent holder and/or considering granting a compulsory license or making government use. For reasons both legal and political there may be situations when challenging the validity of a patent has advantages over trying to obtain a compulsory licence. This would not be the case if compulsory licences were routinely issued through simple administrative procedures.

A patent may be invalid for various reasons. On closer inspection, it may fail one or more of the tests that it was supposed to pass when it was granted.

For example, EPC Article 138 includes grounds for revocation on the basis that the invention is not patentable (for example, the invention falls into a category which is excluded from patentability, such as therapeutic or surgical methods, or the invention is not new or is not inventive), that the patent isn't clear enough about how to carry out the invention, that the patent application or the granted patent has been amended in a way which is not permissible, and that the patent was granted to somebody who was not entitled to it. Some concrete examples include:

• A mistake may have been made during the granting process about whether or not the invention should have been patentable. For instance, GSK claimed to have various patents protecting its antiretroviral medicine Combivir® in Ghana, in order to stop a drug distributor from importing a generic version of this medicine in 2000. Investigations revealed that in fact three of the four GSK patents should not have been granted in the first place, as pharmaceutical inventions were not patentable under the previous Patent Law of Ghana[59].

• Even if the invention falls into a patentable category the patent office may have made a mistake in judging novelty or inventive step in light of the state of the art that the patent search revealed.

• Documents (or something else) describing the invention dating before the priority date may turn up, in which case the invention might no longer be novel or inventive. These sorts of things happen frequently in industrialised countries.

• As was mentioned earlier, TRIPS Article 29.1 obliges WTO Members to require that patent applications "disclose the invention in a manner sufficiently clear and complete for the invention to be carried out by a person skilled in the art". The fact that such a person, for example working in a generic manufacturing company, can prove that it is not possible to carry out the invention on the basis of the information provided in the patent document could also be a motive for revoking the patent.

In some cases, challenging the validity of a granted patent may be a good way to test the law of a country on the issue of patentability. An appropriate definition of novelty or inventive step may not have been debated in the country - the patent office may be operating on developed country patent office rules by default, for example if the patent examiners have been trained in developed country patent offices. The country or region might not yet have debated whether they should regard new uses of known substances, for example, as new[60].

As noted above, a country doesn't necessarily have to examine a patent application before it grants a patent. The TRIPS Agreement does not force countries to apply the patentability tests before a patent is granted. Different countries behave in different ways. Some countries have decided to have a thorough examination of any patent application before a patent is granted. This is the case in the European Patent Office, the United States Patent Office, the Japanese Patent Office and the Chinese Patent Office as well as many others (see p. 18 for some patents that the US office has granted, including a Santa Claus detector). This approach requires a great deal of resources ahead of time in the patent office (at the end of 2001 the European Patent Office had a staff of more than 5,000) but means that fewer invalid patents are likely to be granted.

Then there are patent offices which do not examine each application in depth but merely check that the right papers have been filed and fees paid. This is the case in France, the Netherlands, Nigeria, OAPI and South Africa, for instance. This "registration" approach means much fewer resources need to be invested in patent offices - for instance, there is no need for technically qualified patent examiners.

The USPTO has issued patents for such things as a Santa Claus detector (US patent 5523741), a peanut butter sandwich (US patent 6004596) and a method of swinging sideways on a swing (US patent 6368227).

But it also means that patents will be granted which are not valid under the national law. However, this can only be tested in court. Obviously this approach only works well when there is a reasonable chance that a patent actually will be challenged in court. It might be disastrous if a country where there is little likelihood of anyone challenging the patent uses a registration system.

If the patent application is rejected in, for example, EPO, there might be a good case to invalidate the patent in a "registration only" country[61], to the extent that the law is the same. We discovered cases where a patent had been granted quickly by OAPI, for example, but the corresponding patent in EPO had either been limited compared to the OAPI patent or even refused altogether[62].

The particular way in which the validity of a patent can be challenged is determined by national law. A revocation process or a process to limit a granted patent may take either an administrative route (e.g. in a patent office) or a judicial route (e.g. in the courts), or both. Article 32 of the TRIPS Agreement requires an opportunity for judicial review of any decision to revoke or forfeit a patent. MSF has indicated in its comments on the WIPO Patent Agenda that if moves are made to make the granting of patents easier and cheaper, efforts to make the revocation of patents easier and cheaper must be commensurate.

A potentially vital issue is the determination under national law of who is allowed to challenge a patent. If only competitor pharmaceutical companies were allowed the legal standing to challenge a pharmaceutical patent, then many other relevant entities such as individuals and nongovernmental organizations (NGOs) would be rendered powerless to challenge. A first instance decision in Thailand (see p. 20) recently considered this question and found that an AIDS treatment NGO and two individuals living with HIV/AIDS did have the right to challenge a patent granted on an HIV drug. Any person should be given the legal standing to challenge a pharmaceutical patent given the life-ordeath consequences. Also, a closed group of companies, including generics companies, cannot be relied upon to act in the best interests of public health.

When it is fairly certain that the patent is invalid, a patent can be challenged in a different way, for example, by going ahead and manufacturing or using the product anyway, and waiting for the patent holder to sue. As noted above, patent rights are private rights. Patent holders have to take action if they wish to protect their rights. If they do, the invalidity of the patent is then raised as a defence. If they don't, for whatever reason, then the matter may go no further[63].

One of the biggest practical problems in determining whether a patent is likely to be valid or not is the very limited number of people qualified to do so. Patent law is a complicated field. Although a person skilled in the art is supposed to be able to understand the patent description, it is the claims provided at the end of the patent document (see Annex B) that are judged when deciding if the patent is valid or not. These may only be understood by patent examiners, lawyers and judges. The people involved should have not only a legal background but also a wide-ranging technical understanding so that they can judge the merits of the invention for themselves. It is not at all unusual for a patent lawyer in the field of pharmaceutical inventions to have a PhD in a science or technology associated with pharmaceuticals as well as being a qualified lawyer. In the developing world, there are still very few practising patent lawyers, and when there is a dispute, existing experts might be hired by pharmaceutical companies rather than by NGOs. Similarly, there are very few specialised patent judges to hear patent cases.

Before you can challenge its validity, you will have to find the patent, which can be time-consuming and costly. The next step is understanding what it entails.

The case presented on page 20 shows what can be done when committed groups and individuals join forces and share their expertise to challenge an invalid patent.

Photo: © Sebastien Charles

Revoking an invalid patent: the case of ddI in Thailand

One important medicine in the fight against HIV/AIDS is didanosine (also known as ddI and sold under the name Videx® by Bristol-Myers Squibb (BMS)), a drug included on the WHO Essential Medicines List. The drug was discovered by the US National Institutes of Health, and the US Government holds the rights to the original ddI invention (see patent table)[64]. At the time ddI was discovered, Thai law did not permit the patenting of pharmaceutical products, so even if the US government had wanted to obtain a patent in Thailand, it could not have done so. However, in September 1992, Thai law was changed so that pharmaceutical products could be patented.

BMS licensed the rights to ddI from the US Government. Although BMS could no longer obtain patents for ddI itself, since the structure of ddI was publicly known by then, they could still apply at any time for patents for "derivative" inventions relating to ddI (see section 2.2).

On July 7th 1992, BMS filed just such a patent application in Thailand, intended to protect a specific formulation of ddI[65]. In this patent application, the invention was limited to a specified range of about 5-100mg of ddI per dosage unit.

During the examination of the patent application, the Thai Department of Intellectual Property (DIP) allowed BMS to remove the limitation in the dosage range. In many patent offices it is allowable to amend a patent application, but only so long as certain rules are followed. If the amendment was allowed without following these rules, for example by mistake, and a patent granted, then the patent may be invalid. On January 22nd 1998, the Thai Patent Office granted a patent for this unlimited invention.

The effect of this unlimited patent was apparently to prevent the Thai Government Pharmaceutical Organisation (GPO) from manufacturing any sort of ddI tablet. After a campaign to try to persuade the government to issue a compulsory licence, it was decided to manufacture ddI in a powdered form instead. But the powdered form has an unpleasant taste and side effects that the tablet form does not have, and it is more difficult to take than a tablet.

Accordingly, on May 9th 2001, a case was filed at the Thai Central Intellectual Property and International Trade Court (CIPIT)[66] by three plaintiffs (the AIDS Access Foundation and two people living with HIV/AIDS against two defendants, BMS and DIP). The plaintiffs demanded, among other things, that BMS amend their patent claim back to the limited dosage range originally asked for.

The three CIPIT judges delivered a comprehensive judgement on October 1st 2002.

The judgment clearly confirmed that these two individuals and the NGO had the right to challenge the BMS patent. The legal reasoning for this finding quotes the 2001 Doha Declaration on TRIPS and Public Health - probably one of the first judgements to refer to the Doha Declaration directly. Since the TRIPS Agreement must be interpreted and implemented so as to promote and support access to medicines for the people as a whole and since those suffering from HIV/AIDS can be injured by a patent blocking access to affordable medicines, the judgement says, they had the right to challenge the patent.

The judgement also found that the amendment that BMS made and the Thai DIP allowed was unlawful. It confirmed that under Thai law the most important factor in determining the scope of patent protection is the wording of the patent claims. The scope of the allowable patent claims depends on the details of the invention described to the public in the patent document. One of the reasons that the amendment was unlawful was that the removal of the dosage limitation of about 5-100mg expanded the scope of protection beyond what was described in the patent document description. The judgement ordered BMS and DIP to amend the patent by putting back the limitation.

This judgement was very important and it will give a lot of support to those fighting for access to essential medicines in Thailand and elsewhere in developing countries.

At the time of writing the judgement was under appeal by BMS and DIP.


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