Interpretation Of Markush Claims In A Recent Supreme People's Court Decision

On December 20, 2017, the Supreme People's Court made a Decision (2016) No.41 on a retrial case for Chinese Patent No.: 97126347.7. In this Decision, the interpretation of Markush claims is specified and accordingly the standards as to the amendments to such claims are established.

Markush claims are often found in patent applications for chemical inventions. A Markush claim represents a claim that is drafted by defining alternative elements in parallel therein. The reason that the claim is drafted in such manner is that, for some alternative elements, there is no any generic term available. With such drafting manner, the Markush claim has relatively wide protection scope, and thus once it is granted, the benefit of the patentee would be maximized. However, due to its high generalization, the Markush claim itself is relatively unstable if someone files a request for invalidation against the same. In this scenario, in order to avoid a Markush claim being invalidated, the patentee might choose to amend it by deleting some Markush elements. Due to the contradictory interpretation of the Markush claim between different authorities, however, it has been in dispute for many years as to whether it is acceptable to amend Markush claims by deleting Markush elements during the invalidation proceedings.

There are two views in terms of the Markush claim interpretation:

1. Markush claim relates to an integral technical solution, which is held by the Patent Reexamination Board and Beijing Intellectual Property Court. According to this view, it is not acceptable to amend the Markush claim by deleting Markush elements during the invalidation proceedings. 
2. The Markush claim relates to a collection of individual technical solutions in parallel, which is held by Beijing Higher People's Court. According to this view, it is acceptable to amend the Markush claim by deleting Markush elements during the invalidation proceedings. Under such circumstances, many important cases cannot always obtain consistent examination results, and consequently individual parties cannot obtain exact legal expectation, either.

For settling the above-mentioned dispute, the Supreme People's Court brought up a case involving the amendments to the Markush claim for retrial, and made a decision after careful consideration and investigation for three years.

This case relates to Patent 97126347.7 entitled "a method for preparing a pharmaceutical composition for treating or preventing hypertension", which was filed on February 21, 1992 by Daiichi Sankyo Company Limited and granted on September 24, 2003.

Claim 1 as granted of the subject patent can be read as:

A method for preparing a pharmaceutical composition for treating or preventing hypertension, comprising mixing an antihypertensive agent with a pharmaceutically acceptable carrier or diluent, wherein the antihypertensive agent is at least one compound as represented by Formula (I) or a pharmaceutically acceptable salt or ester thereof,

wherein:

R1 represents alkyl having 1-6 carbons;

R2 and R3 are identical or different and each represent alkyl having 1-6 carbons;

R4 represents:

hydrogen; or

alkyl having 1-6 carbons;

R5 represents carboxyl, COOR5a or –CONR8R9, wherein R8 and R9 are identical or different and each represent:

Hydrogen;

unsubstituted alkyl comprising 1-6 carbons;

alkyl comprising 1-6 carbons and substituted with carboxyl or carbalkoxy having 1-6 carbons in its alkyl moiety; or

R8 and R9 together represent alkylene having 2-6 carbons and substituted with one carbalkoxy having 1-6 carbons in its alkyl moiety;

and wherein R5a represents:

alkyl having 1-6 carbons;

alkylacyloxyalkyl, wherein its alkylacyl moiety and alkyl moiety each comprise 1-6 carbons;

carbalkoxyoxyalkyl, wherein its alkoxy moiety and alkyl moiety each comprise 1-6 carbons;

(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl; or

2-benzo[c]furanonyl;

R6 represents hydrogen; and

R7 represents carboxyl or tetrazol-5-yl.

Beijing Winsunny Harmony filed a request for invalidation against this patent before the Patent Reexamination Board on April 23, 2010, alleging that, among others, claim 1 does not possess inventiveness.

In reply to the request for invalidation, the patentee amended claim 1 by, among others, deleting "alkyl having 1-6 carbons" from the definition of R4, and other options except carboxyl and COOR5a wherein R5a represents (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl from the definition of R5.

The Patent Reexamination Board did not accept the above-mentioned amendments. The court of first instance, namely Beijing Intellectual Property Court, held the same view as that of the Patent Reexamination Board, while the court of second instance, namely Beijing Higher People's Court held a different view from that of the Patent Reexamination Board.

In this decisionthe Supreme People's Court specifies the interpretation of the Markush claim as follows, and accordingly sets standards as to the amendments to the Markush claim during the invalidation proceedings.

As to the interpretation of Markush claims

According to the Supreme People's Court, the Markush claim is a special drafting manner for claims in patent applications for chemical inventions. It is a claim that is generalized by defining alternative elements in parallel in a single claim. The reason that such drafting manner appears initially is that, for some substituents in the chemical field, there is no common generic term available. Such drafting manner per se is always considered as a structural but not functional expression. What is defined in the Markush claim is alternative elements in parallel, but not sub-claims. Despite the particularity of its drafting manner, the Markush claim shall comply with the provisions as to unity. Where the Markush elements represent compounds, the Markush claim shall be considered to have unity where all alternative compounds (1) have common properties and effects, and (2) possess common structures or alternatively all the alternative elements belong to the same compound category recognized in the field to which the invention belongs where said all alternative compounds do not possess common structures.

Furthermore, the Markush claim is highly generalized and thus, once granted, shall have protection scope covering all compounds having common structure, properties or effects, thereby maximizing the benefit of the patentee. Essentially, a patent right means a monopoly of a certain right, and the greater the scope of the patent right owned by the patentee is, the more limitation the public has. Thus, from the view of justice, the interpretation of the Markush claim shall be made strictly. No matter how many variables and combinations the Markush claim comprises, it shall be deemed as a generalized combination solution. Where individual variables are selected, the corresponding individual pharmaceuticals as defined in this Markush claim shall have effects without too much difference, may be replaced with each other, and shall be expected to achieve the same effect. Such an interpretation is in line with the object of Markush claims In view of the above, and the Markush claim shall be deemed as a collection of Markush elements rather than a collection of individual compounds. Generally, the Markush elements shall be interpreted as representing one category of compounds having common properties and effects, and can represent single compounds only under specific situations.

As to the amendment manner to the Markus claim during the invalidation proceedings

The Supreme People's Court held that in view of the particularity for the inventions in the chemical field and that the applicant has opportunities to put all possible structural formulae into one claim when drafting the claims, so as to maximize the protection scope, the amendment to the Markush claim during the invalidation proceedings shall be given strict restrictions, and in principle, the amendments to the Markush claim shall not result in a compound category or single compounds having new property and effect, and the factors relating to individual cases shall be taken into full consideration at the same time. If the patent applicant or the patentee is allowed to delete any option for any variable, even though the protection scope is narrowed and the benefit of the public is not damaged, it would be uncertain whether such deletion results in new protection scope, which neither gives the public stable legal expectation, nor helps to maintain the stability of the system of determining the patent right.

From this decision, two conclusions can be drawn: 

1. The Markush claim shall be deemed as an integral technical solution; and 
2. he Markush claim may be amended by deleting Markush elements during the invalidation proceedings, provided that such deletion does not result in a compound category or single compounds having new properties and effect.

This is Guest post by Wei Yang. She is Partner and Patent Attorney at Co-Talent. 

About Author:

Wei Yang

Partner, Patent Attorney at Co - Talent

E-mail: wyang@co-talent.com  

Educational Background:

1999, obtained the degree of Bachelor of animal physiology and biochemistry from China Agricultural University, China

2002, obtained the degree of Master of physiology from China Agricultural University, China

Qualifications:

2010, registered to practice before the Chinese Patent Office

Professional Experience:

2002, began to conduct research in Bioelectromagnetics at Institute of Electrical Engineering Chinese Academy of Sciences

2006, began to practice IP law at Peksung Intellectual Property Ltd. 

2013, began to practice IP law at Ella Cheong (Hong Kong & Beijing)

2016, founded Co-Talent Intellectual Property Firm

Practice Areas:

Patent application, drafting, prosecution, reexamination, invalidation and litigation in a wide variety of technical fields, particularly biotechnique, pharmaceutics, chemical engineering, organic chemistry.

Languages: Chinese (native); English; Japanese

Membership: All-China Patent Agents Association