Recent changes in the Rules implemented by the European Patent Office (EPO) significantly reduce options available to patent applicants, and will also require more input into the examination process at an earlier stage. The rule changes are in two distinct groups: one dealing with divisional applications and the other with actions required in response to search reports.

Applicants often need to file one or more divisional applications. Sometimes, applicants knowingly file applications that have claims that cover more than one invention, thereby deferring the full cost of filing two or more European patent applications.

In other cases, an original broad claim may be shown to not be patentable, leaving two or more separate variants that are too distinct to be maintained in one application. Previously, a divisional application could be filed at any time up to the grant of original application, and there was no time limit on filing further divisional applications from the first divisional application. Given the large backlogs in the EPO, this lead to some applicants filing divisional applications very late.

The new rules recognize both a "voluntary" divisional application (where the applicant chooses to file without a unity of invention objection from the EPO) and a "mandatory" divisional application (where the EPO has found a lack of unity of invention).

The time limit for filing a voluntary divisional application is 24 months from the first examination report or the notice of allowance if the notice of allowance is issued without an earlier examination report. The EPO has stated that a supplementary European search does not start the 24-month period. Where there is a chain of applications, then it is the earliest such communication on any of the applications.

The time limit for filing a mandatory divisional application is 24 months from any communication of the Examining Division raising an objection during the prosecution of the application; or if the application is a divisional, from the earlier filed European application.

Under the new search rules, the EPO can restrict the scope of the supplementary search for various reasons, including the application containing more than one independent claim in each category or if the claims are too broad and unclear. Unsearched subject matter may be lost from the application and it may only be possible to protect in a divisional application. Therefore, it is prudent to review claims before they are searched to ensure that the EPO will search the desired claims if there is a possible unity of invention issue.

Additionally, it is now mandatory to respond to the supplementary European search, within six months. Therefore, it is now imperative that the European search report be carefully studied and a patent strategy developed based on the report.

Together these rules may place a greater burden on applicants and their advisers, but they could also result in faster examination and earlier issuance of European patents.