The Patent Act does not impose a limit on the number of times and the timing of which one can file for patent invalidation before the expiry of the concerned patent. In order to avoid repeated invalidation applications and subsequent administrative proceedings, Article 33 of the Intellectual Property Case Adjudication Act (hereafter referred to as the "Adjudication Act") stipulates that "In administrative litigation concerning cancellation of a granted patent, the Intellectual Property Court (IP Court) shall take into account any new evidence submitted on the same grounds for the cancellation prior to the end of the oral debate proceeding," thus allowing the entire dispute to be resolved in one proceeding.

Article 33 of the Adjudication Act mentioned above provides the invalidator a chance to submit new evidence during the administrative litigation. However, is there any restriction to apply this provision? More specifically, the administrative litigation for a patent invalidation case may be brought by the invalidator against the Intellectual Property Office's (IPO's) rejection of his/her request for patent cancellation, or by the patent owner whose patent is invalidated by the IPO based on the invalidator's request. The abovementioned provision can inarguably be applied to the former situation; but, for the latter, the invalidator had already obtained a favorable decision during the invalidation procedure, is it still appropriate to allow the invalidator's request that the court review the new evidence submitted by the invalidator in the administrative litigation filed by the patent owner? This issue remains controversial to date.

The Supreme Administrative Court takes a negative position in its 2011-Pan-No.2247 judgment. The Court explained that the legislative intent of Paragraph 1, Article 33 of Adjudication Act is to avoid further administrative litigation resulting from repeated invalidation actions; considering that Paragraph 2 of the same article imposes a procedural requirement that "the IPO shall provide defense briefs in response to the new evidence submitted," only when the invalidator is the plaintiff (meaning the situation that the administrative litigation is filed by the invalidator to challenge the IPO's rejection decision for an invalidation request) can new evidence be submitted by the invalidator. However, the IP Court recently seems inclined to take a positive position in hopes of resolving conflicts once and for all. In other words, even in administrative litigations where the patent owner (as the plaintiff) challenges the IPO's "invalidation decision," the invalidator may still submit new evidence or combinations and have it reviewed by the court.

From the above, it can be found that there is no consensus in Taiwan's judicial practice concerning whether or not Paragraph 1, Article 33 of the Adjudication Act applies only in cases where "the invalidator is the plaintiff." The Supreme Administrative Court also addressed this problem in its 2017-Pan-No.177 judgment; however, the Court only expressed that such issue involves different legal interpretations of this article, but the appellant in that case could not assert that different interpretation constitutes manifestly erroneous in application of law.

According to the resolution of the Supreme Administrative Court's 1st Joint Conference of Presiding Judges (2) held in April 2015 and the opinion of the Supreme Administrative Court 2017-Pan-No.442 judgment, when new evidence is submitted, the IP Court should first confirm whether the patent owner has already "applied for post-grant amendment with the IPO," that "the new evidence should have been sufficiently debated by the parties involved" and that "the disputed issues should have been suitably explained by the court." Only under these circumstances can the court alter the original decision based on the new evidence in accordance with Paragraph 1, Article 33 of the Adjudication Act. Therefore, in cases where the patent owner is the plaintiff, according to the practice of the IPO, the patent owner who is subject to the "invalidation decision" is unable to defend against the invalidator's new evidence submitted after the conclusion of the invalidation proceedings by means of "applying for post-grant amendment" with the IPO. In situations where the IP Court considers the patent owner's complaint against the IPO's invalidation decision to be well reasoned, but the invalidator's new evidence is still sufficient to prove that the patent at issue lacks patentability, the patent owner would be unable to amend patent claims in response. In cases like these, is it still appropriate for the court to directly take a positive position as described above for pursuing dispute resolution in one proceeding and enforcing the rights of the invalidator to submit new evidence, resulting in an imbalance of the patent owner's procedural and actual interests? This issue requires further discussion.