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
New Remedy in China for Fixing "Errors" in a Patent Application: Incorporation by Reference
21 March 2024
Background As mentioned in our earlier article, the Implementation Regulations of the Chinese Patent Law (“Regulations”, similar to the CFR in the US) were approved in November, and the CNIPA finally made public the full text of the Regulations just before the arrival of the New Year. At the same time, the CNIPA also released the new […]
Read more >
2019 CHINA TOP 10 IP CASE: VALEO V. LUCAS, FUKE, & CHEN
8 June 2020
Every year in the spring The Supreme People’s Court of PRC announces its “Top 10 Intellectual Property (IP) cases” and “50 typical IP cases in Chinese courts” of the year. Although not having precedential weight, these cases serve as a reference and guide people's courts at all levels regarding their intellectual property trials. It’s always […]
Read more >
How a Secondhand Ground Brush Wiped Away a Chinese Patent
4 December 2024
A Chinese robot vacuum company digs up “hidden evidence” to successfully invalidate a patent owned by its biggest competitor. Highlights Background With the growth of online shopping, it is easier than ever to provide evidence of a sale when the product is still being sold on the market. But what if the product is no […]
Read more >
China Announcing More Proposed Amendments to the Examination Guidelines in 2022
17 November 2022
It’s been a year and a half since the new Chinese Patent Law came into effect (1 June 2021). Although various versions of draft Examination Guidelines have been released, thus far no official finalized versions have been confirmed. On October 31, 2022, yet another new list of proposed amendments was published1, this time consolidating the […]
Read more >
Our Past Events
Jennifer Che has been Recognized in IAM Strategy 300 Global Leaders 2026
26 November 2025
Jennifer Che has been Recognized as IAM Global Leaders 2026
4 November 2025
Eagle IP is Coming to San Francisco and Washington DC!
15 October 2025
Jennifer Che has been listed on the IAM Strategy 300
15 August 2025
Eagle IP Recognized as Top Tier Firm (Tier 1) for Patent Prosecution in IP Stars 2025 Patent Firms Ranking List
3 July 2025
Dr. Jacqueline Lui, Ms. Pauli Wong, and Mr. Eddie Ho Named Patent Stars by ManagingIP
