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
Updates on Hong Kong Patents Examination Guidelines in 2024
29 February 2024
The Intellectual Property Department of the Government of the Hong Kong Special Administrative Region of the People’s Republic of China (HKIPD) has recently made several updates to the Hong Kong Patents Examination Guidelines, effective from 26 January, 2024. These changes mainly clarify and reflect the Registry’s current practices regarding patent examination for Standard Patent (R) […]
Read more >
China’s Supreme People’s Court (SPC) Hands Down First Patent Linkage Appeal Decision
21 September 2022
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, […]
Read more >
China Hands Down First Batch of Patent Linkage “Paragraph IV” Litigation Results
30 June 2022
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, […]
Read more >
Foreign companies transferring IP out of China: things to know
25 October 2018
Inventions made in China Most foreign companies with R&D sites in China are aware of the fact that inventors having inventions made in China have to obtain permission before they can file patent applications outside of China for these Chinese inventions. It doesn’t matter if the owner of the business is a foreign entity. Patent […]
Read more >
Our Past Events
Dr. Jacqueline Lui, Ms. Pauli Wong, and Mr. Eddie Ho Named Patent Stars by ManagingIP
13 June 2025
Eagle IP Ranked Among Top Tier Firms in IAM Patent 1000
12 June 2025
Jennifer Che from Eagle IP to Attend BIO 2025 in Boston!
11 June 2025
Insights from HKSTP Market Discovery - BIO Connect
28 May 2025
HKMHDIA Medical Fair Forum
27 May 2025
Celebrating Innovation at the Asia Summit for Global Health