Markush claims in China - what can be arbitrarily deleted during invalidation?
Since 2010, the China Patent Re-examination Board (PRB) has published the top 10 patent invalidation cases of the year in April of each year. The selection criteria are high social concern, significant impact on the related industry, or involve difficult legal issues and important examination criteria. Below is one of the top 10 cases that discusses post filing data in China patents.
This case (Beijing Winsunny Harmony Science & Technology Co., Ltd. v. Daiichi Sankyo Co., Ltd) describes an invalidation request of Daiichi Sankyo’s Chinese invention patent 97126347.7 related to processes of preparing pharmaceutical compositions for treating or preventing hypertension. The patent covered the marketed hypertension drug Olmesartan medoxomil.
During the invalidation, the patentee made select amendments to multiple Markush groups, deleting particular individual components from several different R groups of a molecule. The issue at hand is whether these amendments are allowable during an invalidation proceeding, which typically has very strict rules regarding amendments.
Courts Differ on Markush Claims in China
In short, it boils down to how the courts interpret a Markush claim. Does it refers to a general technical solution or parallel embodiments of several technical solutions? If it is one general solution, should you really be able to pick and carve away at its scope? Does doing so create a new scope that has a different technical effect than the original invention? If so, is that allowable?
The Patent Re-examination Board (PRB) and the Beijing High People’s Court (BHPC) disagreed on how to interpret Markush claims in China. The PRB felt that arbitrary amendments should not be allowed because a Markush claim is directed towards a general technical solution. Arbitrarily deleting elements during invalidation would thus create new scopes of protection that could have different technical solutions.
The BHPC thought that Markush groups represented alternate parallel technical solutions, and thus deleting one or more options just narrowed the scope of the claim. The Supreme People’s Court (SPC) ruled that the amendments were allowable. Additionally, the SPC indicated that such types of amendments may be allowed during invalidation as long as the amendments did not generate a scope that possessed a new function or technical effect.
Markush Claims in China Drafting Tips
Applicants should be aware that amendments which carve out a new scope with improved technical effect (as compared to the original scope) may not be allowable. During an invalidation proceeding, it will be difficult to amend claims to a narrower scope with improved technical results to overcome inventive step. Instead, at the time of drafting, applicants should draft several dependent claims directed towards alternate scopes with varying qualities of efficacy, including very narrow claims covering the best, most efficacious compounds. It is risky to rely on being able to carve out scope from broader claims during an invalidation challenge.
A side note on inventive step . . .
Interestingly, this case also briefly discussed inventive step. The petitioners argued that the patent lacked inventive step because a specific embodiment in the patent had equivalent technical effect as a prior art compound. The PRB disagreed and emphasized that inventiveness is actually a three-step determination, and it is inappropriate to directly apply just the “unexpected technical effect” test to see if claims are inventive or not.
Sources: Lexology, Sanyou IP Group
First Ever Successful Invalidation Challenge Due to Unauthorized Foreign Filing
2023年3月8日
What does an invention “completed” in China mean? China and the US are similar in that both countries highly value national security, and thus have rules regulating the exportation of technology and information from within their borders. This includes new inventions that arise from within their respective borders. As such, both governments require inventors who […]
阅读更多 >
SPC Upholds $2M RMB Award in China’s First Patent Case on a Biological Deposit
2022年7月4日
On 28 Feb 2022, China’s Supreme People’s Court (SPC) issued its annual “Judgment Digests”, which includes a list of “48 typical cases” highlighting representative SPC decisions in 2021. The Judgment Digests help us understand more about the SPC’s judicial ideology, trial concepts, and adjudication methods in dealing with difficult and sophisticated legal issues as well […]
阅读更多 >
China’s Supreme People’s Court (SPC) Hands Down First Patent Linkage Appeal Decision
2022年9月21日
China has been implementing a plethora of new laws and measures that are particularly favorable to drug companies, such as patent term extension and patent linkage. Details of the new implementation measures for patent linkage (technically “early dispute resolution mechanisms for drug patents”) came into effect on July 4, 2021. At around the same time, […]
阅读更多 >
No More Hindsight Bias: China’s Supreme People's Court Reins in Patent Inventiveness Assessments
2026年6月25日
For foreign applicants navigating patent litigation or invalidation in China, a common frustration is hindsight bias. Too often, CNIPA or lower courts strip down a patent into isolated technical features, find those features across disparate prior art references, and declare the invention to be "obvious". To counter such hindsight reasoning, the core criterion has always […]
阅读更多 >
我们的过去活动
Jennifer Che Once Again Named to the IAM Strategy 300
2026年8月21日
Yolanda Wang attended the 1st China Pharmaceutical Innovation Conference
2026年7月22日
Pauli Wong as a Guest speaker for “Entrepreneurial Workshop” in Poly U
2026年6月16日
Eagle IP Recognized as Top Tier Firm (Tier 1) for Patent Prosecution in IP Stars 2026 Patent Firms Ranking List
2026年6月5日
Eagle IP Achieves Top Ranking in 2026 IAM Patent 1000
2026年6月2日
Eagle IP to Participate in AIPLA 2026 Spring Meeting in San Francisco
