According to PCT article 41, applicants can contact elected offices to amend the drawings, descriptions, and claims in their patent application within the time limit prescribed. Without applicants' consent, elected offices can't grant or refuse to grant patents before the prescribed time limit has expired.

National Laws of Elected States

Patent Cooperation Treaty amendments should go beyond the disclosure filed in the international application, unless the national laws of elected states permit them to exceed this disclosure. The amendments must be in line with the national laws of elected states in every respect except those not provided for in the Regulations and Treaty.

Where elected offices require translations of an international application, all amendments must be represented in the language of translation.

Voluntary Amendment of Applications

Applicants are allowed to voluntarily amend their applications as long as they make these amendments before the application is filed for substantive examination. Applicants can also voluntarily amend applications within three months after receiving notice from the patent's office that their application has entered the phase of substantive examination.

For the national phase of a patent cooperation treaty application, applicants may voluntarily amend their applications subject to PCT Article 28/41.

There are no additional restrictions that can be applied to voluntary amendments other than the restrictions contained in Article 33. Applicants may also amend their international patent applications when responding to office actions. However, any amendment that is submitted in response to office actions is governed by strict limitations.

Addition of New Claims

New claims cannot be added whether they are dependent claims or independent claims. In view of these limitations, applicants should carefully review all claims before submitting their patent applications. They should make sure that the claims include all the rights they want to protect before the patent application comes under substantive examination.

Procedure Saving Principle

The principle of procedure saving was designed to speed up the examination phase and reduce the search burden after the original search has concluded. In this instance, a broadening of the claim's scope would require a new search.

At this point, all further amendments do not broaden the scope of the patent claim(s). For instance, further amendments are not allowed to change or delete claim limitations, even if these amendments are supported by the original specifications. The basis for this rule is the principle of "procedure saving," which was adopted by the United States Patent and Trademark Office.

Strict Restrictions

There are also very strict restrictions for amendments made to specifications. For instance, during a prosecution, applicants may want to add additional experimental data that was obtained after the patent application was filed in order to satisfy the support requirements. These kinds of amendments are generally not allowed.

Additional Data

In some limited situations, applicants may be allowed to introduce additional data when responding to office actions. In these cases, the additional data will be used only to counter objections based on lack of novelty or obviousness, like in comparative experiments.

However, even if the new data is entered, it cannot be used to support patent claims. This means that no post-filing data can be used to remedy deficiencies.

Petition for Invalidation

Under the current patent law, a granted patent can be challenged by any entity provided this entity files an invalidation petition with the re-examination board.

If the validity of the patent is challenged, owners can amend the patent claims by:

  • A combination of claims.
  • Canceling one or more claims.
  • Deleting one or more group members in a claim.

Special attention should be paid to the timing of these amendments.

Cancellation of Claims

Group members may be deleted or claims canceled at any point during the course of the invalidation procedure.

However, the incorporation of a claim is only allowed:

  • When new arguments or evidence that was not previously presented by the petitioner is introduced by the Board.
  • When new evidence and/or argument is introduced by the petitioner.
  • When sending a reply to the invalidation petition.

When combining different claims, the claims to be combined should not depend on each other. They should depend on the same independent claim.

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