Drug patent linkage originated as an innovation from the 1984 Hatch-Waxman Act in the US to provide legal solutions to potential patent infringements before a generic drug launches into the market. It refers to procedurally linking the approval of the sale of a generic drug and its patent validity review; and functionally linking the US Food and Drug Administration (FDA) and the US Patent and Trademark Office (USPTO).
Jumping ahead to 1 October 2017, China’s general offices of the CPC Central Committee and the State Council called for exploring drug patent linkage and lowering the patent infringement risks of generic drugs with their Opinions on Deepening the Reform of the Evaluation and Approval Systems and Encouraging Innovation in Drugs and Medical Devices, aiming to incentivise generic drug development.
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Sanyou Intellectual Property Agency
In October 2020, the linkage system was formally introduced into the fourth amendment to the Patent Law, an upper-tier law in China’s legislative hierarchy. The National Medical Products Administration (NMPA) and China National Intellectual Property Administration issued the Measures for Implementation of the Mechanism for Early Settlement of Drug Patent Disputes (interim) on 4 July 2021.
The following day, the Provisions on Several Issues concerning the Application of Law in the Trial of Civil Cases involving Patent Disputes Related to Drugs of which Applications for Registration are Filed and the Administrative Adjudication of the Mechanism for Early Settlement of Drug Patent Disputes were released by the Supreme People’s Court and the China National Intellectual Property Administration (CNIPA), respectively. Drug patent linkage was thereby implemented in administration, lawsuit and administrative adjudication.
Patent classifications
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Sanyou Intellectual Property Agency
Registered drug patents in the US can be classified into drug substance (active ingredient) patents, drug product (formulation and composition) patents, and method-of-use patents.
In China, a drug can be patented as a chemical drug, traditional Chinese medicine or a biological product. Chemical drugs may be further registered as pharmaceutical active ingredient compound patents, pharmaceutical composition patents containing active ingredients, or patents for medical use. As the matter of stay and exclusivity periods do not apply to traditional Chinese medicine or biological products, this article will focus on drug linkage differences between China and the US in terms of chemical drugs.
Patent declaration
Paragraph II certification in the US means that a patent has expired in spite of its inclusion in the Orange Book, the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations.
Duty of notification
Paragraph IV certification in the US requires that the generic drug must notify the patentee and the marketing authorisation holder within 20 days from the acceptance of application. The patentee and holder may file a lawsuit within 45 days of receiving the notification.
Under a class four declaration, China’s equivalent, the NMPA should make a public announcement within 10 working days of accepting a generic drug application, and the applicant should submit the declaration and its basis to the marketing authorisation holder, which is entitled to file a lawsuit or apply for administrative adjudication by the CNIPA within 45 days from the announcement date.
Dispute resolution
Generic drug patent infringement is determined via judicial proceedings in the US, while applications for patent invalidation may be submitted to a court or the USPTO.
In China, generic drug patent infringement can be determined by courts via judicial proceedings, or by the CNIPA via administrative adjudication. Patent invalidation, on the other hand, must be submitted to the CNIPA.
Stay period
In the US, a stay period of 30 months will be imposed by the FDA if the patentee or the marketing authorisation holder files a lawsuit within the defined limitation of action. A stay period can only be ordered once but may be shortened or prolonged by the court.
In China, after receiving a notification of case initiation from the court or a copy of CNIPA’s notice of acceptance, the NMPA will impose a nine-month stay period.
Exclusivity period
In the US, the first generic drug that successfully challenges the patent and launches into the market is entitled to a 180-day exclusivity period, which will be invalidated if the first applicant:
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- Fails to market the drug within 75 days after the date on which the approval of the application is made effective, or 30 months after the date of submission of the application.
- Withdraws the application.
- Amends or withdraws the certification for all of the patents with respect to which that applicant submitted certification qualifying the applicant for the 180-day exclusivity period.
- Fails to obtain tentative approval of the application within 30 months after the date on which the application is filed.
- Enters into an agreement with another applicant, the holder of the application for the listed drug, or an owner of the patent, and the agreement has violated the antitrust laws.
- All of the patents as to which the applicant submitted certification qualifying it for the 180-day exclusivity period have expired.
The exclusivity period in China is 12 months, but cannot exceed the patent term of the challenged drug. The conditions for losing exclusivity remain undefined in China’s regulations.
Our thoughts
China’s drug patent linkage system mirrors the US framework, but also deviates from it where the national situation calls for such a change. For instance, given that China has a shortage of new drugs, first generic drugs are given preferential treatment, such as a shorter stay period and longer exclusivity, to encourage their earlier launch.
China’s drug patent linkage system is still in a nascent stage, with more refined and detailed provisions on the way – a much anticipated development.
Pang Dongcheng is a partner, and head of the foreign-related chemistry department and the patent search and consultation department, and Li Dongxiu is a patent agent of the foreign related chemistry department at Sanyou Intellectual Property Agency
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