How to Construe a Close-ended Claim – Injection Consisting of Adenosine Disodium Triphosphate and Magnesium Chloride

Shanxi Zhendong Taisheng Pharmaceutical Co., Ltd. et.al. v. Hu Xiaoquan – How to Construe a Close-ended Claim (Civil Judgment (2012) Min Ti Zi No. 10 by the Supreme People’s Court on December 20, 2012)

When patent claims are granted a patent right, the public will determine the extent of patent protection in accordance with the relevant regulations and the terms of patent claims, and then decide what business strategy to apply. If a patentee fails to come up with a proper manner of drafting the claims during the patent prosecution for various reasons, and chooses close-ended claim which has a relatively narrow extent of protection, then the granted patent claims, when enforced, cannot cover the desired extent of protection. The highlight of this case is the confirmation that generally a close-ended claim of a chemical composition shall be construed as the composition merely consisting of the indicated components, and including no other components but impurities in a normal amount, while adjuvants do not belong to the impurities.

The patentee, HU Xiaoquan, owns a patent for invention No. ZL 200410024515.1, titled “Process for the Preparation of an Injection of Adenosine Disodium Triphosphate and Magnesium Chloride,” wherein claim 2 recites the additional technical features, “a freeze-dried powder injection of adenosine disodium triphosphate and magnesium chloride for injection, consisting of adenosine disodium triphosphate and magnesium chloride at the ratio by weight of 100 mg to 32 mg.”

The alleged product, adenosine disodium triphosphate and magnesium chloride for injection, is also an injection in the form of white or off-white freeze-dry lumps or powders. The main components of the freeze-dry powder are adenosine triphosphate disodium salt at a dosage of 100 mg and magnesium chloride at a dosage of 32 mg. However, in the process of the preparation of the alleged product, arginine and sodium bicarbonate, are added.

Both the Jinan Intermediate People’s Court for the first instance and the Shandong High People’s Court for the retrial held that the adjuvants in the alleged product are not the main components, and do not affect the composition, the weight ratio of “adenosine triphosphate disodium and magnesium chloride” in the injection. The alleged product has the same features as the patented product, which fell into the scope of protection of the patent at issue, and constitutes infringement.^[1]

The alleged infringers, Shanxi Zhendong Taisheng Pharmaceutical Co., Ltd. et.al., filed a request for retrial with the Supreme People’s Court, arguing that claim 2 of the patent is a close-ended claim, so the infringement cannot be established as long as the alleged product comprises any other component which is not recited in the claim, regardless of whether other component is an active ingredient.

After hearing the Supreme People’s Court considered that the controversial focus of this case is on the extent of protection of a close-ended claim, i.e. claim 2.

The Supreme People’s Court held that in order to safeguard the reliance interest of the public in the claim scope of granted patent right, when a patent infringement proceeding involves the extent of protection of a patent, a close-ended claim shall generally be interpreted as not including any component or process step other than those recited in the claim. When drafting the claims, the patentee can choose, according to the specific situations, an appropriate drafting manner among an open-ended mode, a close-ended mode, a close-ended mode for active components, and a partially close-ended mode, to obtain a proper extent of patent protection. The claim of the patent concerned (i.e. claim 2) explicitly employs the transition phrase “consisting of” for a closed-ended mode as specified in the Guidelines for Patent Examination, therefore, it is a close-ended claim and its claim scope should be determined according to the normal interpretation of a close-ended claim. That is, the freeze-dry powder injection of adenosine disodium triphosphate and magnesium chloride for injection claimed by claim 2 of the patent concerned contains only adenosine disodium triphosphate and magnesium chloride, but no other component, except for impurities in a normal amount. However, adjuvants do not belong to impurities, and an injection containing adjuvants is thus excluded from the scope of claim 2 of the patent concerned.

Based on the above interpretation, the exclusion of the other components is also an inherent feature of a close-ended claim. Compared with claim 2 of the patent concerned, the alleged product further comprises arginine and sodium bicarbonate, and therefore it does not constitute infringement. The Supreme People’s Court ultimately reversed the judgments of the first instance and retrial.

Remarks

First, Rule 6 of Interpretations of the Supreme People’s Court on Certain Issues Concerning the Application of Law in the Trial of Patent (hereinafter, referred to as “the Interpretation (2009)”) interprets the application of the doctrine of prosecution history estoppel in patent infringement dispute cases. To enhance operability, this Interpretations emphasizes on the restrictive amendments or observations actually made by a patent applicant or patentee. The doctrine of prosecution history estoppel applies regardless of 1) whether such amendments or observations are made on the patent applicant or patentee’s own initiative or in answer to the examiner’s invitation, 2) whether there is any causal legal relationship between such amendments or observations and approval of patent right, or 3) whether such amendments or observations are ultimately accepted by the examiner.^[2]

In this case, the applicant of the patent concerned had tried to amend the description and claims to read “the main components consist of adenosine triphosphate disodium and magnesium chloride” in response to the second office action issued by the State Intellectual Property Office during the substantive examination of the patent application. However, the examiner rejected the amendments for “going beyond the scope of disclosure contained in the initial description and claims” and hence violated the provisions under Article 33 of the Chinese Patent Law. In the end, the applicant amended the product claims as the approved.

Second, Rule 7 of the Interpretation (2009) stipulates that the all-limitations rule applies to a determination of patent infringement. An accused technical solution will be determined to fall into the scope of protection of a patent claim as long as the accused technical solution contains all the limitations of the claim. It does not matter whether the accused technical solution contains any additional limitation. However, for a closed-ended claim to a composition of matters, if an accused technical solution contains other components than those explicitly recited components of the claim, then the accused technical solution shall be found non-infringing instead of falling into the claim scope by construing the other components as “additional limitation,” which does not relate to the finding of an infringement.^[3]

In this regard, the Beijing High People’s Court adds in Guidelines for Determining Patent Infringementissued in year 2013 that: a closed-ended claim to a composition of matters shall be interpreted as containing only the explicitly recited components, with the exception of any additional technical features in an accused technical solution that does not have any substantive influence on the properties, and technical effects of the composition, or as inevitable impurities in a normal amount. In practice, however, sometimes it is a tough problem to inquire whether an influence is a “substantial” influence. Moreover, chemistry is an experimental science, and the technical effects need to be verified by providing a large volume of experimental data. It is highly possible that both plaintiff and defendant will provide experimental data in favor of him or herself, which may further complicate the courts to verify the experimental data as evidence.

In this case, the courts of first instance and retrial both held that the adjuvants are not the main components, and the alleged product has all the technical features of the patented product. The courts of first instance and retrial are obviously wrong, as the alleged product having the additional components “arginine and sodium bicarbonate” does not infringe the asserted patent claim in a close-ended mode either literally or under the doctrine of equivalents. Meanwhile, the Supreme People’s Court clarified the applicability of the doctrine of equivalents to patent infringement of a close-ended claim, where it indicate that once a patentee chooses a close-ended claim, it means that the patentee has explicitly excluded any component or process step other than those recited in the claim from the scope of patent protection, and it is not justifiable for the patentee to re-claim the surrendered subject matters through the doctrine of equivalents. The doctrine of equivalents shall be applied on a limitation-by-limitation basis rather to the “invention as a whole”.

Last, as far as this case is concerned, the drafting of the patent application contains many flaws, and this is the main reason why the asserted patent claim cannot cover the alleged product. If the patentee had recognized the restriction on the extent of protection of a close-ended claim when drafting the patent application, he might avoid using a closed-ended mode, and choose an open-ended claim for a broader scope of protection. In prosecuting the patent application, the patentee had tried to amending the completely close-ended claim to the injection to a closed-ended mode of the main components of the injection. However the amendment was rejected for “going beyond the scope of disclosure contained in the initial description and claims”. This defeated the patentee’s attempt to expand the claim scope. From this we can learn that it would be better to make the disclosure of the description enough to leave room for later amendments to claims.

Written by Zhenwei ZHOU and Lingling TAN

Author Profile: Mr. Zhou is a patent assistant in our Japanese & Korean division.

Email: zhenwei.zhou@beijingeastip.com

Ms. Tan is a patent attorney in our biological & chemical division.

Email: lingling.tan@beijingeastip.com

Injection Consisting of Adenosine Disodium Triphosphate and Magnesium Chloride Case – PowerPoint Presentation (Chinese Version)

[1] The Supreme People’s Court ordered the Higher People’s Court of Shandong to retry the case due to the erroneous application of the law in second instance.

[2] Kong Xiangjun, Wang Yongchang, Li Jian. Certain Issues on the Application of Interpretations of the Supreme People’s Court on Certain Issues Concerning the Application of Law in the Trial of Patent [J]. Electronic Intellectual Property, 2012, (2): 80-84. .

[3] KONG Xiangjun, WANG Yongchang, LI Jian. Certain Issues on the Application of Interpretations of the Supreme People’s Court on Certain Issues Concerning the Application of Law in the Trial of Patent [J]. Electronic Intellectual Property, 2012, (2): 80-84.