Most third party challenges to patentability occur in front of national or regional patent offices. WIPO recently released a summary of data regarding the extent to which third parties are challenging patentability at the international level.
專利申請程序中，第三方是指專利申請方、審查主管機關以外的公眾。在PCT國際階段，公眾可提出第三方意見 （Third Party Observation，TPOs），但必須與系爭專利之新穎性（novelty）及進步性（inventive step）有關，而非專利不明確（indefiniteness）、缺乏可實施性（lack of enablement）、或缺乏支持（lack of support）等其他領域事由。透過系統提交的第三方意見，每次可引用最多10筆文件，次數不限，可以包括對於引述文件之相關性說明，每筆文件說明最多5000個字母。
The observations must relate to novelty and inventive step, but not other grounds such as indefiniteness, lack of enablement or lack of support. Any member of the public can file Third Party Observations (“TPOs”) against a PCT application during the international phase. Observations can include an explanation of relevance of the cited documents up to a maximum of 5000 characters for each cited document. The observations are filed through the ePCT system. A maximum of ten documents can be cited per observation (multiple observations are permitted).
TPOs are accepted from time of international publication until 28 months from the priority date. The applicant has an opportunity to respond to each observation. The aim of this process is to provide a cost-effective system to assist international and national patent offices to become aware of pertinent prior art. If the prior art is unlikely to be located by an individual patent office, then it may be particularly practical and cost-effective for a third party to file the prior art one time at the PCT international level, rather than case-by-case in national offices. For a third party to wait and see how prosecution unfolds at the PCT national stage may necessitate monitoring of multiple national filings and then multiple individual filings of the prior art.
If a separate US application is co-pending with the PCT, then filing a TPO can be a useful technique to cause the applicant to file the prior art in the separate US application in a US information disclosure statement.
From the point of view of the applicant, a TPO can also be helpful by allowing the applicant to make better-informed decisions regarding the patentability of inventions earlier on in the patenting process.
It has been more than 5 years since WIPO introduced the process. On January 31, 2018, WIPO published a circular analyzing the use of the system in its first 5 years.
WIPO分析發現，使用TPO程序的頻率高低，與專利申請的發明領域有關，最常提出的TPOs的是高分子化學（macromolecular chemistry）、及食品化學（food chemistry fields）領域，其中一種解釋為TPOs僅限於針對新穎性（novelty）及進步性（inventive step）提出意見；另一解釋則是，異議第三方除了在提交TPOs之初可以簡單陳述外，後續無法參與進一步審議過程。
The process appears to be in little use. A total of 1,422 TPOs were accepted in relation to 1,394 international applications through the system. This represents just around 0.15% of published international applications. WIPO found that the frequency of use of the process appears to depend on the field of the invention, with the highest use noted in macromolecular chemistry and food chemistry fields. One explanation for these findings is that TPOs are limited to only circumstances where novelty and inventive step are at issue. Another is that the process is limiting in that third parties cannot participate in the proceedings beyond the initial filing of the observations (which allow for a very brief argument).
After the initial observations are filed, the applicant would then be free to characterize the prior art however it wishes. That said, it appears that most applicants do not take any action at the PCT level in response to observations. Only 4.5% of applicants filed a response to observations. It appears that most applicants prefer to deal with prior art at the national stage, once they see how the prior art is characterized by national/regional patent offices.
WIPO found that the most common number of cited documents in an observation is just one. The average is 3.8 citations per observation. As such, this process appears to be most commonly employed where there is a single piece of prior art (presumably the prior art is arguably anticipatory or very close).
有趣的是WIPO分析指出，第三方往往會在受理截止期限前才提交TPOs，據統計33% TPO是在最後一周送出，WIPO提出建議，那些拖到最後才提出的TPOs，不但在國際申請案的國際初步審查（international preliminary examination）來不及納入考慮，專利申請人也來不及做出回應，且若國際局駁回（reject）內容有誤的TPOs時，亦無法在期限前要求修正版本。
Interestingly, the circular noted that there is a great tendency for third parties to leave the filing of their observations until the last minute, with around 33% of TPOs received in the final week. The circular cautioned that in such instances the late prior art cannot be considered for international preliminary examination. This also prevents applicants from filing a response and the International Bureau from rejecting defective observations and requesting corrected versions before the expiration of time.
One explanation for this tendency may be that third parties do not want to alert applicants of deficiencies in their application at a time where it is possible to take corrective action at the international stage. Filing a last minute observation appears to be a good way for a third party to flag prior art for national offices, without analysis at the international stage.
In summary, TPOs in the PCT can be an effective way for a third party to indicate early that a patent application may not be novel and inventive. Although, the frequency with which TPOs are filed appears to be low, TPOs may nonetheless have some usefulness. TPO’s should be kept in mind when highly relevant, anticipatory prior art is located and the third party wants a cost effective way to flag the prior art for patent offices at an early time point.