There are four regional patent systems. The oldest is the European Patent Office. In the EPO, it is possible to file an application in one of the three official languages – English, German, or French – and obtain patent protection in one, several or all of the 30 contracting states.
Once the patent application issues, the patent is essentially exchanged for a patent from all of the designated countries that were selected during the application process.
The EPO does not provide a uniform enforcement mechanism. The patentee must rely upon the local laws of the member states to enforce the patent.
The Organisation Africaine de la Properiété Intellectuelle or OAPI is an organization of 12 French-speaking African countries. The OAPI is unique among the four regional patent systems in that the patentee obtains a single patent that is valid in all 12 nations upon issuance of the patent. However, the patent may be interpreted differently in each of those countries.
The African Regional Industrial Property Organization is an organization of 16 English-speaking African countries. The Eurasian Patent Office is an organization of 12 former soviet republics. EAPO and ARIPO are similar to the EPO in that the organizations allow applicants to file a single patent application that may be converted to multiple patents in designated contracting states upon issuance.