Patent linkage was introduced into the 4th amendments to the Patent Law of the People’s Republic of China effective June 1, 2021. Unprecedentedly, Article 76 of the Patent Law provides a "dual-track" early resolution mechanism for resolving drug patent disputes during the marketing approval process of generic drugs, allowing innovative drug patent holders to institute a civil action or an administrative determination against generic drug applicants in order to stay the marketing approval process for generic drugs.

With the patent linkage system in place, the volume of drug patent disputes has been expected to rise. This week will see six oral hearings about invalidation requests filed by Chinese companies against global pharmaceutical giants including Merck, Novartis, and AstraZeneca. Two oral hearings before the Reexamination and Invalidation Department of the China National Intellectual Property Administration were conducted on March 28 and 29 and four more are to come on March 30 and 31.

Invalidation request 1

Patent: Phosphoric acid salt of a dipeptidyl peptidase-iv inhibitor

Patent No.: ZL200480017544.3

Petitioner: Hangzhou Zhongmei Huadong Pharmaceutical Co., Ltd. (杭州中美华东制药有限公司)

Respondent: Merck & Co., Inc.

Oral hearing date: March 28

US-based Merck applies this patented invention in Sitagliptin, which is an anti-diabetic medication used to treat type 2 diabetes, sold under the brand name Januvia (佳糖维) among others. Januvia, as the world’s first drug in the DDP-4 inhibitor class, was developed by Merck and approved for medical use in the United States in 2006. In 2019, it was the 88th most commonly prescribed medication in the United States, with more than 8 million prescriptions. Januvia had reached global sales of about $4 billion in 2014. It had registered sales of about $60 million in China in 2020.

Over 10 invalidation requests are recorded to have been filed against the patent by Chinese entities. The latest one was filed by CSPC Pharmaceutical Group (石药集团有限公司) in 2021.

Invalidation request 2

Patent: Phosphoric acid salt of a dipeptidyl peptidase-iv inhibitor

Patent No.: ZL200680036174.7

Petitioner: Ni Yefeng (倪业锋)

Respondent: Novartis International AG

Oral hearing date: March 29

Switzerland-based Novartis applies this patented invention in Vildagliptin, which is the world’s second anti-diabetic drug in the DDP-4 inhibitor class, sold under the brand name Gulvas (高糖优适) among others. The drug’s global sales are over $1 billion every year.

Two invalidation requests are recorded to have been filed against the patent by Chinese entities. The latest one was filed by Beijing HuiKang Boyuan Chemical Tech Co., Ltd. (北京汇康博源医药科技有限公司) in 2018.

Invalidation request 3

Patent: Remedy for overactive bladder comprising acetic acid anilide derivative as the active ingredient

Patent No.: ZL200380102889.4

Petitioner: Qilu Pharma Co., Ltd. (齐鲁制药)

Respondent: Astellas Pharma, Inc.

Oral hearing date: March 31

Japan-based Astellas applies this patented invention in Mirabegron, which is a medication used to treat overactive bladder, sold under the brand name Myrbetriq (米拉贝隆) among others. VESIcare (卫喜康), an overactive bladder drug developed by Qilu, was approved by the U.S. Food and Drug Administration to be sold in the US in 2018.

Invalidation request 4

Patent: Crystalline solvates and complexes of (IS) -1, 5-anhydro-L-C- (3- ( (phenyl) methyl) phenyl) -D-glucitol derivatives with amino acids as SGLT2 inhibitors for the treatment of diabetes

Patent No.: ZL200780024135.X

Petitioner: Sichuan Gowell Pharmaceutical Co., Ltd. (四川国为制药有限公司)

Respondent: AstraZeneca plc

Oral hearing date: March 31

British-Swedish multinational company AstraZeneca applies this patented invention in Dapagliflozin, which is a medication used to treat type 2 diabetes, sold under the brand names Farxiga (安达唐) among others.

Founded in 2005, Gowell develops and manufactures drugs to treat cardiovascular and cerebrovascular disorders, digestive disorders, infections, and urinary disorders. The company has filed about 70 patent applications, 40 of which have been granted.

Invalidation request 5 and 6

Patent: Endovascular access devices are connected to the connector of control member, the thrombosis device agglomerate of removable combination

Patent Nos.: ZL201380069871.2, ZL201310471114.X

Petitioner: Shanghai HeartCare Medical Technology Corp. Ltd. (上海心玮医疗)

Respondent: Medtronic plc

Oral hearing date: March 30, March 31

US-based Medtronic is the world’s largest medical device company by revenue. Shanghai HeartCare got listed on the Stock Exchange of Hong Kong in 2021. The company develops and manufactures neuro-interventional and cardiac medical devices.