The patent term extension provisions [3] apply to any utility or plant patent application filed on or after May 29, 2000. The provisions are aimed at ensuring that, except where the patent is subject to a terminal disclaimer, the term is extended for one day for each day that prosecution has been delayed as a result of delays caused by the USPTO. The changes remove the caps on the terms of possible extensions as a result of secrecy orders, interferences and appeals that were introduced when the term of a patent was changed from seventeen years from grant, to twenty years from filing, and adds to the situations in which extensions may be granted. The legislative history makes it clear that the objective is to ensure that "no applicant diligently seeking to obtain a patent will receive a term of less than seventeen years."

Delays that will trigger such extensions include: failure to issue a first action within 14 months, failure by the USPTO to respond to an applicant's response to an official action or to an appeal within four months of the applicant’s response or appeal, failure to act on a decision by the Board of Patent Appeals and Interferences or a court within four months and failure to issue a patent within four months of payment of the issue fee (the 14-4-4-4 rule). Additionally, any overall delay extending total pendency to beyond three years from the actual date of the application in the United States (that is, in the case of PCT applications the date of national phase entry in the United States) will trigger an extension. However, no account is to be taken of delays requested by the applicant, including obtaining extensions of term for response to official actions, unless the applicant "in spite of all due care" was unable to respond within the three month period.

Extensions will be based on the number of days that the USPTO delayed prosecution, less the number of delayed days that can be attributed to the applicant. USPTO Rules will determine how such extensions are to be calculated and any anticipated extension will be notified to the applicant on the notice of allowance, although this assumes that there will be no delay by the USPTO in issuing the patent after this point. Appeals from any determination of an extension under this provision are to be by way of a civil action brought before the U.S. District Court of the District of Columbia.

3.1 Rules for Calculating Reductions in Any Possible Extended Term

The USPTO issued rules for implementation of the Patent Term Guarantee Act on September 18, 2000. [4] The rules apply to applications filed on or after May 29, 2000 and make it clear that, although not quite as severe as were the proposed rules, at least with respect to compliance with formalities at the time of filing, almost anything that could be said to be the fault of the applicant will be treated as a failure to diligently seek the grant of a patent and will be counted against him or her so as to take days off any extension that might result from the delays caused by the USPTO. Thus, among other things, delaying filing of a preliminary amendment so that the examiner has to issue a supplemental action, failure to reply fully to an office action, failure to reply to most office actions, including missing parts actions calling for the filing of missing declarations, sequence listings in proper form and the like, within three months [5] (unless the applicant can show that despite all due care the applicant was unable to reply within three months), filing a supplemental response to an office action, requesting suspension of the prosecution, allowing the application to become abandoned and failure to seek reinstatement promptly if the application does become abandoned, failure to file an appeal brief with a notice of appeal and filing an amendment after a notice of allowance, can all result in time being deducted from any extension that might be allowed. The filing of a continuing application results in any USPTO delays that occurred before the filing of the continuing application being discounted. The period of any adjustment is to be set out in the notice of allowance, except for any extension that may result from a delay in the issue of the patent after payment of the issue fee and applicants will have the right to petition for a different period no later than the date of payment of the issue fee.