Korea has a very flexible but complicated system for "correction" (post-grant narrowing/clarifying amendment) of patents in response to invalidation challenges. If an invalidation action is brought against a patent at the IPTAB, the patentee may respond by filing a petition for correction of the patent, and the IPTAB will evaluate whether to accept the correction and review the validity of the corrected patent claims, or reject the correction and review the claims as-is. In addition, if an invalidation action decision is appealed to the Patent Court or the Supreme Court, the patentee may file an independent action at the IPTAB for correction of the claims, with the aim of having the corrected claims (if the correction is accepted) be the subject of such appeals.

On January 22, 2020, the Supreme Court issued an en banc decision that substantially limits the usefulness of filing independent correction actions that may only be decided after a negative validity decision is issued by the Patent Court (Supreme Court en banc Decision 2016Hu2522). It is common practice for a patentee to file one or more independent IPTAB correction actions in the course of the Patent Court appeal or even after the Patent Court decision issues, to respond to new arguments or evidence submitted during the appeal, or a negative validity decision by the Patent Court. Where a correction is only finalized after the Patent Court issues a negative validity decision, it has been the practice of the Supreme Court until now simply to reverse the Patent Court invalidity decision in view of the correction and remand for further proceedings on the corrected claims. This practice has been criticized for resulting in unnecessary back-and-forth proceedings between the Patent Court and the Supreme Court without involving the Supreme Court's substantive review, which in turn lengthens the process of adjudicating patents.

In its recent decision, the Supreme Court has now essentially ruled that a correction action that is only finalized after a Patent Court proceeding on the relevant patent has closed will no longer be a basis for overturning such a Patent Court decision. In other words, the mere fact that an independent correction action successfully narrows/clarifies the patent claims will no longer suffice to overturn a Patent Court decision on the patent being corrected if the correction action is only finalized after the Patent Court proceedings are closed, unless there is another independent basis to reverse the decision. In this particular case, subsequent to receiving a negative Patent Court decision, the patentee filed a correction action that was decided favorably within two months, yet the Supreme Court held that the successful correction alone was an insufficient basis to overturn the Patent Court decision, explaining that it expects patent disputes to be resolved more quickly as a result of its change on this issue.

As a result of the Supreme Court's decision, patentees will be well advised not to unduly delay filing independent correction actions where needed, and to spend some effort as well to persuade the Patent Court to wait for the results of any independent correction action that is filed. It is possible the IPTAB and the Patent Court will make additional changes to their practices regarding correction actions in view of the Supreme Court's decision as well.