Starting in July of this year, China initiated a patent registration platform that bears some similarity to the generic drug framework under the Hatch-Waxman Act in the U.S. The purpose of this alert is to describe this new Patent Linkage System in China and to compare it to the corresponding generic drug framework in the U.S.

On July 4, 2021, the National Medical Products Administration (NMPA), in conjunction with the China National Intellectual Property Administration (CNIPA), released the "Measures for the Implementation of Early Resolution Mechanisms for Drug Patent Disputes (Trial)" (药品专利纠纷早期解决机制实施办法 (试行), hereinafter, the "Measures"), setting up a patent registration platform for chemical drugs, biological products, and traditional Chinese medicines, with a bifurcated adjudication system (by courts or CNIPA), as well as mechanisms for staying market approval based on registered patents and adjudication outcome for chemical drugs. The Measures also award an exclusivity period to the first generic applicant who succeeds in challenging such registered patents. While the Chinese framework for generic drugs appears to be modeled after the United States generic drug framework under the Hatch-Waxman Act, the China Patent Linkage System also covers biological products. In contrast, the regulatory framework for biosimilar products in the United States is set forth under the Biologics Price Competition and Innovation Act (BPCIA), with the publication of a patent list for reference biological products implemented under the Biological Product Patent Transparency (BPPT) section of the Consolidated Appropriations Act of 2021.¹

Patent Registration System (Applicable to Chemical Drugs, Biologics, and Traditional Chinese Medicines)

According to the Measures, a patent registration system² has been established for the Marketing Authorization Holder (MAH) to register certain patents applicable to the approved drug product and to keep the information up to date. The MAH can register and keep up to date in the Patent Registration System drug information (such as generic name, registration number, dosage form, and strength), patent information (patent number, patentee/licensee, title, issue date, expiration date, legal status, type of claims, and the relation of claims to the approved drug), and correspondence information (such as address and contact information of the contact person).

Patents for chemical drugs, biologics, and traditional Chinese medicine can be registered, although there are certain limitations on the types of patents that can be registered. For a chemical drug, a patent covering the active pharmaceutical ingredient (API), a patent directed to a composition comprising the API, and a patent directed to medical use of the API can be registered, while for biologics, the Measures only list patents directed to the API in the form of sequence/structure information and its medical use.

The Patent Registration System in China covers both chemical drugs and biological products, and in this sense, it serves a function similar to both the Orange Book³ and the Purple Book.⁴

Patent Certification (Applicable to Chemical Drugs Only)

For registered patents on approved chemical drugs, generics need to make a patent certificate of any of the following types:

1. There are no relevant patents registered;
2. The registered patent has expired or has been declared invalid or the generic applicant has a license;
3. There is a registered patent and the generic applicant will not market the drug until expiration of the patent; and
4. There is a registered patent on the platform, but it should be invalid, or it does not cover the generic.

Generics are also required to provide to the patent owner supporting materials together with the patent certification that the registered patent does not cover the generic drug. Such supporting materials are comprised of:

• Technical description of the generic drug;
• Claim chart comparing the registered patents and the generic drug; and
• Relevant technical materials.

In the United States, the Hatch-Waxman Act provides four similar types of patent certifications for generic drug applicants.

Patent Challenge and Bifurcated Adjudication System (Applicable to Chemical Drugs Only)

For a Type IV certificate, the MAH or patent owner will have the option to bring it to court or CNIPA's adjudication whether or not the patent covers the generic drug within 45 days. According to its own preference, the patent owner may choose either the court or the CNIPA for such adjudication. However, an existing court proceeding preempts a subsequent CNIPA proceeding on the same subject matter.

Upon the instatement of the court or CNIPA proceeding, NMPA will hold off the approval of the generic drug for nine months, which is compared to the 30-month stay in the United States. Within this nine-month period, NMPA will not approve the generic drug unless the generic is determined as not infringing or the patent invalid, or the MAH or patent holder withdraws the case. That is, either a litigation in a court or a proceeding in the CNIPA may trigger the nine-month stay in China, while in the United States, a patent owner has to file a patent infringement suit in federal court against the generic applicant in order to trigger the 30-month regulatory stay of FDA approval of the ANDA, subject to certain limitations.

Exclusivity Period

The Measures award an exclusivity period up to 12 months to the first successful challenger of the registered patents, provided that the market exclusivity does not extend beyond the term of such patents.

In the United States, 180 days of market exclusivity is provided to the first generic applicant who files a substantially complete ANDA with a paragraph IV certification against a listed patent, which begins to run from the earlier of the following: (a) the date the generic applicant begins commercial marketing of the generic drug product, or (b) the date of a court decision that finds the listed patent is invalid, unenforceable, or not infringed. The 180-day generic exclusivity cannot extend beyond the term of the patent specified in the paragraph IV certification, as the generic applicant would no longer be eligible for the exclusivity if the patent expires, at which time the FDA may approve other eligible ANDAs.

The table below compares some key aspects of the Chinese framework with the U.S. framework.

	China			U.S.
	Chemical Drug	Biological Product	TCM	Chemical Drug (Hatch-Waxman Act)	Biological Product (BPCIA)
Type of listed patents	API, pharmaceutical composition, medical use	Active ingredient, medical use	Extract, pharmaceutical composition, medical use	Drug substance or API, composition, formulation, method-of-use, product-by-process (Orange Book)	Purple Book Patent List5
Adjudication system to trigger stay	Court or CNIPA	N/A	N/A	Federal court	N/A
Time to sue/petition	45 days	N/A	N/A	45 days	N/A
Stay of approval	9 months	N/A	N/A	30 months	N/A
Market exclusivity for first successful challenger	12 months	N/A	N/A	180 days	N/A

For questions relating to the Chinese drug patent linkage system, please contact Karen Wong or Richard Wang. For questions relating to U.S. patent strategy or the Hatch-Waxman Act, please contact any member of the patents and innovations practice or the patent litigation practice. For questions relating to FDA approval and regulatory exclusivities, please contact any member of the FDA regulatory, healthcare, and consumer products practice.

Richard Wang and Eva Yin contributed to the preparation of this Wilson Sonsini Alert.

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[1] In the United States, the BPCIA provides a general framework for the patent dispute resolution process, also known as the “patent dance,” for biosimilar applicants, although biosimilar applicants are not required to engage in the patent dance. Unlike the Hatch-Waxman Act, the BPCIA does not have provisions comparable to the paragraph IV certification or 30-month regulatory stay provided for generic drugs under the Hatch-Waxman Act. The BPPT section of the Consolidated Appropriations Act of 2021 required the FDA to publish patent lists provided by sponsors of reference biological products no later than 180 days after its enactment, or June 25, 2021.

[2] https://zldj.cde.org.cn/list?listType=PublicInfoList.

[3] FDA, Orange Book, available at https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm.

[4] FDA, Purple Book, available at https://purplebooksearch.fda.gov/.

[5] The FDA has stated that its publication of the Purple Book Patent List “is ministerial, and FDA does not consider the applicability of patents to a biosimilar product (e.g., validity, enforceability, or potential infringement) in publishing the information ….  FDA intends to verify only that the Reference Product BLA number, Applicant Name, Proprietary Name, and Proper Name match those in the Purple Book.” FDA, FAQs, available at https://purplebooksearch.fda.gov/faqs.