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
Beijing IP Court Reverses CNIPA Decision and Upholds Ozempic® semaglutide patent in China as VALID based on Novo Nordisk’s Post Filing Data
27 June 2024
Recently, all eyes have been on China as the fundamental patent covering semaglutide, the active ingredient in Ozempic® and Wegovy®, will expire on March 20, 2026. It goes without saying that generics are ramping up bigtime in China (and also around the world), preparing to manufacture and sell this blockbuster drug to one of the […]
Read more >
New Fee Standards Released for Chinese Patent Applications
6 September 2024
Recently, the Chinese government issued four official notices introducing new fee standards and deduction rules for Chinese patent applications.1 These updates address international applications (PCT applications) and the Chinese national phase applications thereof, as well as patent term adjustment/extension (PTA/PTE). Please find our summary below: PCT application fee deduction rules Application fee & extra […]
Read more >
Patent Eligibility for Software in China
4 April 2022
Technology has progressed significantly since the early days of patent law, when US lawmakers in 1952 could only envision patentable subject matter into categories like “process, machine, manufacture, or composition of matter.” The recent explosion of new types of innovations that don’t fall neatly into these categories has resulted in a game of catch-up, where […]
Read more >
China Releases Details on Patent Term Extension, Deferred Examination and More in the Latest Draft Implementation Rules of the New Chinese Patent Law
11 December 2020
The China National Intellectual Property Administration (CNIPA) is moving forward at breakneck speeds aiming to get all the necessary pieces in place for the June 1, 2021 date when the new 4th Amendment of the Patent Law will come into effect. Most recently, this means a flurry of drafts coming out from CNIPA, including, but […]
Read more >
Our Past Events
Jennifer Che Once Again Named to the IAM Strategy 300
21 August 2026
Yolanda Wang attended the 1st China Pharmaceutical Innovation Conference
22 July 2026
Pauli Wong as a Guest speaker for “Entrepreneurial Workshop” in Poly U
16 June 2026
Eagle IP Recognized as Top Tier Firm (Tier 1) for Patent Prosecution in IP Stars 2026 Patent Firms Ranking List
5 June 2026
Eagle IP Achieves Top Ranking in 2026 IAM Patent 1000
2 June 2026
Eagle IP to Participate in AIPLA 2026 Spring Meeting in San Francisco
