What determines a patent's in-force duration?
1. Since the Uruguay Round Agreements in 1994, many countries have enacted laws providing that the enforceable term of patent protection begins on the date of grant of a utility patent (durations may differ for other types of patents such as industrial design and plant cultivar patents), and ends 20 years from the filing date of the application. The 20 year term is a minimum for compliance to TRIPS Article 33, but nations may choose to grant longer terms. Some countries, such as the USA, have provisions for limited recovery for infringement occurring between the date of publication of the application and date of grant.
2. For patent applications filed prior to the adoption of conformity to the Uruguay Round, laws varied. For example, in the US patent term was 17 years from issue date, unrelated to the filing date. " Submarine" patent applications, chains of applications filed perhaps many years previously but on which patents had not yet issued, could be an unknown quantity because the patent applications were not published. An example of this is the Barton-Chilton Agrobacterium transformation patent that issued in the US in 2000 for a 17 year term, although the first filing of the invention in an application had taken place in 1983.
3. The actual first filing date of a particular patent application is not always the same as the filing date that determines whether claims to the invention are "valid over the prior art". The date that determines this, the "priority date" of the invention, is the date that determines whether information available to the public at that time could have anticipated the invention or made it obvious, therefore unpatentable (the rules for what constitutes invalidating prior art differ from one country to another).
- The Paris Convention for the Protection of Industrial Property offers a priority period (one year for utility patent applications) within which patent applications filed in one member country can be filed in other member countries. The application in the foreign country will be treated, for the purposes of examining prior art, as if it had been filed on the same date as the first application filed in another Paris Convention member country, so the effective filing date is the date of the earlier application. However, in accordance with the provisions of the Paris Convention for the Protection of Industrial Property, the term of a patent cannot include the Paris Convention priority period, so the term dates from the filing date of the application itself and not from the effective filing date under the Paris Convention. The maximum patent term is still 20 years.
- In the U.S. at present there is also a similar domestic priority system since June 8, 1995. For the purposes of examining prior art, applicants will be entitled to claim the benefit of priority in a given application based upon a previously filed application in the United States, but if that application is a "provisional" application, the domestic priority period, of maximum one year, does not start the clock for the measurement of the patent term. The maximum patent term is still 20 years.
- In the U.S., if the application is a continuation, divisional, or claims priority to a foreign pending application, the patent term will end twenty years from the date on which the earliest application referred to was filed.
4. Patents can lapse if required maintenance fees are not paid. Many countries require the payment of annuities annually, or maintenance payments at other intervals. Sometimes assignees knowingly or unintentionally fail to make such payments, so a patent that would otherwise be predicted to have a longer term may not actually be in force.
5. Some countries offer various kinds of adjustments to patent terms.
- Sometimes the patent term is extended for reasons of national interest. For example, in the European Community, law provides for extension of the patent term for patents disclosing new drugs for human use, to compensate for patent term lost while the patentee is unable to market a product because government approval is still pending. This is intended to provide a greater incentive for investment into research, opposing the counter-incentive of lengthy regulatory approval processes. Similar patent term restoration is provided by Japan, Israel, the U.S. and many other countries.
- In some countries restoration of patent term for time spent in regulatory approvals extends to other types of medical devices, veterinary products and the like, but most often agricultural biotechnology patent applications are not considered under this rubric despite lengthy regulatory approval processes for food crops.
- Compulsory licensing is almost the opposite case, in which the government, having granted a patent monopoly, effectively retracts it so that the invention can be used by others in addition to the patentee. There are specific conditions for invoking compulsory licensing, e.g. anti-trust concerns, failure of the owner to either work the patent for a specified period of time or license it, etc. A compulsory license may make the technology available with or without a royalty, and it may be made available for all users, or only for certain users such as domestic manufacturers meeting certain criteria. For example, there are provisions in laws for compulsory licensing if the patent owner refuses to make the invention available to license, or if the invention is not being used in the country, e.g. in Brasil, or for various public interest reasons, such as to correct lack of availability of pharmaceuticals at low prices by allowing the production of generics early, e.g. in France.
- In the US, if the issue of a patent is delayed due to interference proceedings (a procedure attempting to resolve disputes over who was first to invent a particular technology), a secrecy order, or in other limited circumstances such as delays in patent office handling, the term of the patent can be extended for the period of delay, up to a total of five years. If it has been so extended, the extended portion of the term of the patent can be reduced for any period of time during which the applicant did not act with due diligence, such as replying in timely fashion to a patent examiner's question or office action.
6. Patents are sometimes partially in force and partially annulled. For example, in many countries a patent that has been granted can be partially voided by litigation, or partially voided by the patent office if it appears that legal requirements were not followed, but usually a non-voided claim of the patent, if it still meets patentability requirements, remains in force.