Which drugs will be affected by the new patent rules?

The TRIPS Agreement requires WTO Member States to introduce patent protection only to products "invented" after 1 January 1995², i.e. products for which a patent application has been filed in a WTO Member State after 1995. This means that, in accordance with TRIPS, products already on the market cannot be given patent protection, because if they are already marketed, they are not new, and so do not meet the TRIPS conditions necessary to grant a patent. Therefore, only new drugs or new indications, formulations or processes invented after 1995 should be patentable in all WTO Member countries.

²Or a year before, if priority is claimed.

However, because developing and least-developed countries are entitled to transitional periods, and some will not grant drug patents before 2000, 2005 or 2006, a special provision in the TRIPS Agreement preserves the novelty of drugs that may be invented between 1995 and the end of the transitional periods. Developing and least-developed countries not granting drug patents must have a system, often referred to as a "mail-box" system, to store patent applications as from 1995 until the transitional period expires. At this time, the various patent applications waiting in the "mail-box" will be examined according to the TRIPS standards and, if granted, the patent term, which starts from the filing date, will last for what remains of the 20 years.