Recently, in the second invalidation action filed by an Anhui agricultural company against KUMIAI CHEMICAL INDUSTRY CO., LTD. (“Kumiai”) over its patent covering a key intermediate of pyroxasulfone (the “Patent”), GENLaw, acting for Kumiai, once again secured a favorable decision, with the China National Intellectual Property Administration (“CNIPA”) upholding the full validity of the Patent.

The Patent, titled “Process for producing 5-alkoxy-4-hydroxymethyl pyrazole compound”, protects a key intermediate compound of KUMIAI’s innovative herbicide pyroxasulfone (the “Patented Compound”).

This case was handled by GENLaw partners Jerry Xia, James Ma, Simon Du, and associates Yin Chao, Melody Ye, Wang Yulu, and Kim Zhao.

Case Background

KUMIAI is one of the world’s leading agrochemical companies with over 70 years of experience in manufacturing herbicide products. Its flagship herbicide product, pyroxasulfone, since its market launch in 2011, has gained increasing prominence in the agrochemical market due to its broad-spectrum efficacy, high efficiency, low dosage requirements, and long-lasting effectiveness, becoming a crucial option for mainstream crop weed control globally. KUMIAI holds a global patent portfolio, including but not limited to Chinese patents related to intermediate compounds and manufacturing processes of pyroxasulfone herbicide.

On November 12, 2014, the Patent was granted in China, titled "Process for producing 5-alkoxy-4-hydroxymethyl pyrazole compound", with patent number ZL201210121587.2. The Patent is KUMIAI's core patent in China concerning pyroxasulfone herbicide intermediate compounds.

In June 2024, GENLaw, acting for KUMIAI, filed a patent infringement lawsuit against an Anhui agricultural company. The company subsequently initiated the first invalidation proceeding before the CNIPA against the Patent. In August 2025, CNIPA issued a decision maintaining the Patent’s full validity.

In September 2025, the Anhui agricultural company launched a second invalidation proceeding against the same patent. CNIPA recently issued its decision, once again maintaining the Patent in full.

Case Analysis

The Anhui agricultural company argued that the Patented Compound would arise as an impurity in the synthetic route for pyroxasulfone, thus contending that the claimed technical solution lacked practical applicability.

In its invalidation decision, CNIPA gave a clear response to this argument: “Practical applicability” means that the technical solution protected by the claims can be made or used in industry and is capable of producing a beneficial effect. The specification of the Patent expressly states that the compound may be used as an intermediate in the preparation of pharmaceuticals, agrochemicals, and other products. On that basis, the fact that the compound may also exist as an impurity in a particular synthetic route is insufficient to negate its practical applicability as an intermediate.

GENLaw has represented KUMIAI in a series of complex enforcement actions in China, including patent infringement litigation and patent invalidation proceedings. We are honored to have helped KUMIAI secure another success in this invalidation action, further confirming the stability of the Patent. Going forward, our team will continue to support KUMIAI and steadfastly advance its enforcement efforts in China.

See KUMIAI’s press release regarding this case:

https://drive.google.com/file/d/1SCxdVO49qsrdkQwfnf3w_yk8NILbKV63/view?usp=sharing