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
Chinese Courts Cares More About Patent Quality Now (A Doctrine of Equivalents Story)
13 December 2022
There is no doubt that the drafting quality of a patent can be crucial in determining the success (or failure!) of the patent during litigation. However, due to various reasons, patents often fail to use the right drafting strategies that best protect the invention. Too often, inexperienced or unsophisticated patent drafters merely listen to an […]
Read more >
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 >
CHINA: How Prohibiting "Illegal" Inventions Runs into Food Safety Law
22 October 2021
Chinese Patent Law has an interesting provision that specifically prohibits patent protection on “illegal” or “immoral” inventions. What does this mean, exactly? According to Article 5.1 of the Chinese Patent Law, “no patent shall be granted for an invention that contravenes any law or social moral or that is detrimental to public interests.” On its […]
Read more >
IP Strategies for the Newly Released Implementation Regulations of the 4th Amendment of the Chinese Patent Law: Part 2: Grace Period without Loss of Novelty
7 February 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 […]
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
