Wei Yang, Partner of  IP March

 The pharmaceutical industry is among the most heavily patent‑dependent sectors. On the one hand, new drug development is characterized by high investment, long cycles, and considerable risks. Without a robust patent system, innovative companies would find them difficult to recoup their R&D expenditures or obtain reasonable returns, which would inevitably dampen their incentive for sustained innovation. On the other hand, because drugs are directly linked to public health and life safety, virtually all countries subject them to stringent administrative regulatory systems, requiring them to pass multiple review and approval stages, including preclinical safety evaluations and clinical trials, before they can be marketed. This means that even after a pharmaceutical product invention patent has been granted, the patentee still cannot implement the invention until the drug has officially obtained marketing approval. This situation objectively and significantly shortens the effective term of patent protection.

To compensate for the loss of patent term resulting from the lengthy marketing-approval process for innovative drugs, many countries and regions, including the United States, Japan, South Korea, the European Union, and Canada, have introduced a patent term extension (PTE) system or equivalent mechanisms. In recent years, China has also placed great emphasis on balancing the protection of pharmaceutical innovation with public health. In 2017, it issued the Opinions on Deepening the Reform of the Review and Approval System to Encourage Innovation in Pharmaceuticals and Medical Devices, and in 2019, the Opinions on Strengthening Intellectual Property Protection, both of which explicitly called for exploring the establishment of a patent term extension system for pharmaceutical products.

Against this backdrop, the fourth amendment to the Patent Law in 2020 added a new paragraph (paragraph 3) to Article 42, formally instituting a patent term extension system for new drugs, designed to compensate for the time occupied by the review and approval of new drugs prior to market launch. This design strikes a balance among multiple interests: it reinforces the protection of the legitimate rights of innovative pharmaceutical companies and encourages their continued R&D of originator drugs; it also prevents over-protection of innovative pharmaceuticals and encourages timely generic competition, thereby lowering drug prices, enhancing drug accessibility, and ultimately achieving a balance between public interest and public health.

I. Basic Information About the PTE System in China

1. Article 42.3 of the Chinese Patent Law

The Chinese Patent Law stipulates in Article 42.3 that, to compensate for the time occupied by review and approval procedures for a new drug, for an invention patent related to a new drug that has obtained marketing approval in China, the China National Intellectual Property Administration (CNIPA) shall, upon request by the patentee, grant a patent term extension; the extension shall not exceed five years, and the total effective term of patent protection after the marketing approval of the new drug shall not exceed fourteen years.

2. Eligible Party and Timing for Filing a PTE Request

Pursuant to Article 42.3, a PTE request for a pharmaceutical product patent shall be filed by the patentee. If the patentee is not the same as the marketing license holder, the patentee must obtain the written consent of the marketing license holder.

In addition, the patentee shall file the PTE request with the CNIPA within three (3) months from the date on which the marketing approval for the drug is obtained in China.

3. Definition of “New Drug” and Eligible Categories for the PTE Procedures

With respect to the definition of “new drug,” the definition set forth in the Drug Administration Law and its Implementing Regulations applies to the Chinese Patent Law. Specifically, the new drug refers to a drug that has never been marketed either within or outside China, in other words, a globally new drug. Under such circumstances, it is clear that the PTE system provided in Article 42.3 does not apply to approved chemical drugs in Category 5.1 or to biological products (vaccines) that have obtained marketing approval outside China and are subsequently launched in China (i.e., innovative or improved drugs first marketed abroad and then introduced into China).

Furthermore, it should be noted that the “new drug” in this context refers only to pharmaceutical products for human use, and does not include veterinary drugs or medical devices.

The Guidelines for Patent Examination stipulate in Part V, Chapter 9, Section 3.4 that the PTE system under Article 42.3 applies only to the following new drugs approved by the National Medical Products Administration (NMPA):

(1) Innovative drugs in Category 1, including chemical drugs, biological products for prevention (vaccines), biological products for treatment, and traditional Chinese medicines; and

(2) Improved new drugs, including:

v  Chemical drugs in Category 2.1 that comprise an ester or a salt of a known active ingredient;

v  Chemical drugs in Category 2.4 that contain a known active ingredient for a new indication;

v  Biological products for prevention in Category 2.2 being a vaccine with an improved bacterial or viral strain;

v  Biological products for treatment in Category 2.2 involving a newly added indication;

v  Traditional Chinese medicines in Category 2.3 with additional actions and indications.

Accordingly, the “technical solution related to a new drug” refers to the technical solution that pertains to a new drug in any of the above categories, and such technical solution serves as a bridge connecting the approved new drug with the patent for which a PTE request is filed.

4. Invention Patents Eligible for PTE Request

Similarly, the expression “an invention patent related to a new drug” in Article 42.3 refers to an invention patent that pertains to a new drug in any of the above categories. It is worth pointing out that not every invention patent related to a new drug in the specified categories is eligible to file a PTE. More specifically, only an invention patent related to an active pharmaceutical ingredient (API) comprised in a new drug in the specified categories is eligible to file a PTE.

The term “active pharmaceutical ingredient” or “API” refers to the substance or component in a new drug that plays a substantive role in preventing, treating, or diagnosing a disease. Thus, if an invention patent is not related to the improvement of an API, but rather to the improvement of other ingredients such as excipients or adjuvants in the new drug, or to the development of a new dosage form, that invention patent is not considered an invention patent related to an API, and is therefore not eligible for a PTE request.

Furthermore, an invention patent related to an API can be classified into three types:
(1) a product comprising the API,
(2) a preparation method of the API, and
(3) a medical use of the API.

In addition, the invention patent may protect the API itself or a composition or pharmaceutical composition comprising the API. As a general principle, the specified claim(s) in an invention patent related to an API shall include or relate to the API comprised in the new drug that has obtained marketing approval.

5. Conditions for Filing a PTE Request

The following conditions must be satisfied when filing a PTE request:

(1) The issue date of the patent for which a PTE is requested shall precede the date of marketing approval of the drug;
(2) The patent shall be valid at the time the PTE request is filed;
(3) The patent has never been granted a PTE;
(4) The claim(s) of the patent for which a PTE is requested shall cover the technical solution related to the new drug that has obtained marketing approval;
(5) Where a drug is covered by multiple patents, the patentee may request a PTE for only one patent; and
(6) Where a patent covers multiple drugs, the patentee may request a PTE for that patent based on only one of those drugs.

6. Determination as to Whether the Specified Claim(s) Include the Technical Solution Related to a New Drug

The technical solution related to a new drug shall be determined based on the structure, composition, and content of the approved new drug, the approved manufacturing process, and the approved indications, with reference to the granted claim(s) as specified by the patentee.

In addition, the technical solution related to a new drug shall be related to the API in the approved new drug and have the same subject matter as the specified claims. In particular, the technical solution related to a new drug should be taken as:

(1) the API per se, without limitation to a particular indication, if a product claim (which provides absolute protection for the claimed product) is specified;
(2) the approved manufacturing process of the new drug, without limitation to a particular indication, if a method‑of‑preparation claim (which may extend to a product directly prepared by the method) is specified; and
(3) the use of the approved new drug for the approved indication, if a medical use claim is specified.

In addition, when determining whether a specified claim includes the technical solution related to a new drug, the protection scope of the specified claim shall be construed in accordance with the general principles of claim construction and interpretation applied in patent examination proceedings, with reference to the content of the patent specification where necessary. The specified claim is then compared with the technical solution related to the new drug to determine whether the specified claim covers that technical solution. Only when the specified claim covers the technical solution related to the new drug, a PTE may be granted to the invention patent.

With respect to the general principles of claim construction and interpretation, a specified claim is considered to cover the technical solution related to the new drug if it satisfies at least the following requirements:

(1) All‑element rule: the specified claim specifically defines the technical solution related to the new drug;
(2) Generic concept coverage principle: the specified claim employs a generic concept, and the technical solution related to the new drug is a specific concept falling thereunder; and
(3) Numerical range coverage rule: the actual value(s) of the new drug’s parameters (e.g., content) fall within the numerical range set forth in the specified claim.

7. Calculation of the PTE Period

The PTE period for a pharmaceutical product patent is calculated as follows:

(1) PTE period = D₁ – D₂ – 5, wherein,

①　D₁ refers to the Date of marketing approval of the drug,

②　D₂ refers to the filing date of the patent, and

③　the PTE period shall not exceed 5 years; and

(2) The total remaining effective patent term = (D₃ – D₁) + the PTA period (if any) + the PTE period, wherein,

①　D₃ refers to the expiry date of the patent, and

②　the total remaining effective patent term shall not exceed 14 years.

8. Protection Scope of the Invention Patent During the PTE Period

Pursuant to Rule 83 of the Implementing Regulations of the Patent Law, during the PTE period, the protection scope of a patent related to a new drug shall be restricted to the technical solutions relating to the new drug and to the approved indication only. Therefore, the protection scope of the patent during the PTE period is much narrower than the original protection scope.

For example, if a specified claim protects a compound of formula A, and the API comprised in the approved new drug for a certain indication is compound A₁, which falls within the scope of formula A, then during the PTE period, the protection scope of the patent shall be restricted to compound A₁ for treating the approved indication only, rather than to compound A₁ per se.

II. Several Cases Subject to the PTE Procedures

A. PTE‑Granted Cases

(1) Novartis / Sacubitril Valsartan Sodium Tablets (Entresto)
For patent No. 200680001733.0 entitled “Pharmaceutical combinations of an angiotensin receptor antagonist and an NEP inhibitor” issued to Novartis AG, a patent term extension of 1,826 days was granted based on the approval of the new drug Sacubitril Valsartan Sodium Tablets (Entresto). The new drug comprises hexasodium (4-{[(1S,3R)-1-([1,1'-biphenyl]-4-ylmethyl)-4-ethoxy-3-methyl-4-oxobutyl]amino}-4-oxobutanoate) (N-pentanoyl-N-{[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl}-L-valinate) hydrate (1/15) as API, and is used for treating essential hypertension. The specified claims are claims 1, 2, 6 and 7, which protect a complex comprising said API.

(2) Remegen / Telitacicept for Injection
For patent No. 200710111162.2 entitled “Optimized TACI‑Fc fusion protein” issued to Remegen, a patent term extension of 1,827 days was granted based on the approval of the new drug Telitacicept for Injection. The new drug comprises an optimized fusion protein consisting of a truncated TACI and immunoglobulin Fc, and is used for active, autoantibody‑positive systemic lupus erythematosus (SLE). The specified claims are claims 1 and 9.

(3) Chia Tai Tianqing‑Akeso / Penpulimab Injection
For patent No. 201610705763.5 entitled “An anti‑PD1 monoclonal antibody, pharmaceutical composition and use thereof” issued to Chia Tai Tianqing‑Akeso, a patent term extension of 140 days was granted based on the approval of the new drug Penpulimab Injection (for lung cancer treatment). The new drug comprises an anti‑PD‑1 monoclonal antibody, and is used for treating recurrent or metastatic nasopharyngeal carcinoma. The specified claims are claims 1‑13, claims 32‑33, and claim 34, which protect an anti‑PD1 monoclonal antibody or antigen‑binding fragment thereof, a pharmaceutical composition comprising the same and the medical use of the anti‑PD1 monoclonal antibody or antigen‑binding fragment thereof, respectively.

(4) Novartis & Astex Therapeutics / Ribociclib Succinate Tablets
For patent No. 200980141314.0 entitled “Pyrrolopyrimidine compounds as CDK inhibitors” issued to Novartis AG and Astex Therapeutics, a patent term extension of 1,826 days was granted based on the approval of the new drug Ribociclib Succinate Tablets (a CDK4/6 inhibitor). The new drug comprises a pyrrolopyrimidine compound serving as a CDK inhibitor. The specified claims are claims 1, 3, and 8‑10, which protect a pyrrolopyrimidine compound, a pharmaceutical composition comprising the compound, and the medical use thereof, respectively.

(5) Roche & PTC Therapeutics / Risdiplam Powder for Oral Solution
For patent No. 201580027306.9 entitled “Compounds for treating spinal muscular atrophy,” issued to Roche and PTC Therapeutics, a patent term extension of 36 days was granted based on the approval of the new drug Risdiplam Powder for Oral Solution. The new drug comprises a compound of formula (I) and is used for treating spinal muscular atrophy. The specified claims are claims 1‑11, 16‑18, 20, 22, 25‑28, 31, 34, and 44‑47, which protect a compound of formula (I), a pharmaceutical composition comprising the compound, and the medical use of the compound, respectively.

(6) Suncadia & Jiangsu HengRui / Camrelizumab for Injection
For patent No. ZL201480011008.6 entitled “PD‑1 antibody, antigen‑binding fragments thereof and its medical use” issued to Suncadia and HengRui, a patent term extension of 389 days was granted based on the approval of the new drug Camrelizumab for Injection. The new drug is a PD‑1 antibody, and is used for treating recurrent or metastatic cervical cancer. The specified claims are claims 1, 6‑11, and 20‑22, which protect a PD‑1 antibody, antigen‑binding fragments thereof, a pharmaceutical composition comprising the same, and the medical use of the antibody, respectively.

B. PTE‑Rejected Cases

(1) Shandong Luye Pharmaceutical / Patent No. 200610073308.4
For patent No. 200610073308.4 entitled “Compounds for interrupting reuptake of 5‑hydroxytryptamine and norepinephrine, preparation method and use thereof” issued to Shandong Luye Pharmaceutical, the PTE request was rejected on the grounds that (±)‑4‑(2‑(dimethylamino)‑1‑(1‑hydroxycyclohexyl)ethyl)phenyl 4‑methyl benzyl benzoate hydrochloride dihydrate, the API comprised in the approved new drug Toludevin Lafasin Hydrochloride Extended‑Release Tablets, was not covered by the specified claims, which protect a compound of formula (I), an optical isomer or pharmaceutically acceptable salt thereof.

(2) Shaanxi Xin'an Pharmaceutical Technology / Patent No. 200610166893.2
For patent No. 200610166893.2 entitled “Levornidazole Phosphate, preparing method and use thereof” issued to Shaanxi Xin'an Pharmaceutical Technology, the PTE request was rejected on the grounds that the new drug was approved before June 1, 2021.

(3) Jiangsu HengRui / Patent No. 201380012703.X
For patent No. CN201380012703.X entitled “Macrocyclic derivatives for treating proliferative disorders” issued to Jiangsu HengRui, the PTE request was rejected on the grounds that the approved new drug Camrelizumab for Injection was a chemical drug in Category 5.1.

(4) Novartis / Patent No. 201180066851.0
For patent No. 201180066851.0 entitled “Pharmaceutical composition” issued to Novartis AG, the PTE request was rejected on the grounds that the new drug was listed as “adding an indication that has been approved outside China but not yet approved within China”.

(5) Novartis / Patent No. 201080046640.6
For patent No. 201080046640.6 entitled “Combination” issued to Novartis AG, the PTE request was rejected on the grounds that the new drug was listed as “adding an indication that has been approved outside China but not yet approved within China”.

(6) Recordati / Patent No. 201180006082.5
For patent No. 201180006082.5 entitled “Use of an adrenal hormone‑modifying agent” issued to Recordati, the PTE request was rejected on the grounds that the approved new drug was a chemical drug in Category 5.1.

(7) Sumitomo / Patent No. 200880007780.5
For patent No. 200880007780.5 entitled “Pleuromutilin derivatives for the treatment of diseases mediated by microbes” issued to Sumitomo Pharmaceuticals, the PTE request was rejected on the grounds that the approved new drug was a chemical drug in Category 5.1.

(8) AIC246 / Patent No. 200480011928.4
For patent No. 200480011928.4 entitled “Substituted dihydroquinazolines having antiviral properties” issued to AIC246, the PTE request was rejected on the grounds that the approved new drug was a chemical drug in Category 5.1.