Beijing Winsunny Pharmacy Co., Ltd. v. Daiichi Sankyo Co., Ltd. (Administrative Judgment (2012) Gao Xing Zhong Zi No. 833 by the Court on Sep. 24, 2013)
A Markush claim should be interpreted as a collection of a plurality of parallel alternative technical solutions instead of a single generic technical solution. Accordingly, during examination and invalidation proceedings, it is allowed to delete any alternatives of any variables from a Markush claim. A Markush claim involves an inventive step only when every particular compound as claimed produces unexpected effects or has unexpected use as compared with a prior art compound of similar structure.
Daiichi Sankyo Co., Ltd. (Daiichi Sankyo) owns Chinese Patent No. 97126347.7 (‘347 Patent), where the allowed Claim 1 read as follows:
A process for preparing a pharmaceutical composition for the treatment or prophylaxis of hypertension, which comprises mixing an anti-hypertensive agent with a pharmaceutically acceptable carrier or diluent, in which the anti-hypertensive agent is at least one compound of formula (I) or a pharmaceutically acceptable salt or ester thereof,
R¹ represents an alkyl group having from 1 to 6 carbon atoms;
R² and R³ are the same or different and each represents an alkyl group having from 1 to 6 carbon atoms;
R⁴ represents a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms;
R⁵ represents a carboxy group, a group of COOR5a in which R5a represents …, or a group of formula -CONR⁸R⁹, in which R⁸ and R⁹ are the same or different and each represents …;
R⁶ represents a hydrogen atom; and
R⁷ represents a carboxy group or a tetrazol-5-yl group.
The Beijing Winsunny Pharmacy Co., Ltd. (Winsunny) requested to invalidate ‘347 Patent on the ground of lack of inventive step over the prior art EP0324377A2. In response to the challenge to the inventiveness, Daiichi Sankyo tried to amend Claim 1 by removing “or ester thereof”, removing “or an alkyl group having from 1 to 6 carbon atoms” from the definition of R4 and removing “or a group of formula -CONR⁸R⁹ …” from the definition of R5.
The Patent Reexamination Board (PRB) concluded that the removal of “or esters thereof” is acceptable, but the change of definitions of R4 and R5 is not acceptable. The PRB also concluded that Claim 1 (after the removal of “or esters thereof”) involves an inventive step based on the findings that there are some differences between formula (I) defined in Claim 1 and formula (I) of EP0324377A2 in terms of some substituents, that the prior art provides no teaching of replacing the substituents mentioned in EP0324377A2 with those defined in Claim 1, and that the claimed compounds produce unexpected technical effects over the reference compound provided in the description of ‘347 Patent.
After Winsunny appealed this case to the Beijing First Intermediate Court, the Beijing First Intermediate Court dismissed the appeal and ruled that the PRB’s decision is correct. Then, Winsunny filed the second appeal to the Beijing High Court (the Court hereinafter), which court reversed the PRB’s decision, and dismissed the first-instance judgment.
The Court held that the PRB and the Beijing First Intermediate Court are wrong in rejecting the deletions of some elements from Markush claims. In addition, the PRB and the Beijing First Intermediate Court adopted a wrong methodology in evaluation inventiveness of Markush claims because the inventiveness of a Markush claim requires “each compounds covered [by the claim] should have unexpected effects or have unexpected use over a similar specific compound mentioned in the prior art [if such a compound exists in the prior art]”. The Court concluded that Claim 1 does not involve an inventive step because some particular compounds within the scope of Claim 1 do not produce unexpected effects over Example 329 of EP0324377A2, a particular prior art compound with structure very similar to these compounds.
In 2014, the Beijing High Court listed this case as one of “2013 Top Ten Creative IP Cases” as it clarifies how to correctly interpret Markush claims.
Interpretation and Analysis
- Amendments to Markush Claims in view of the nature of Markush claims
In one respect, the present case relates to amendments to claims during invalidation proceedings. According to the Guidelines for Examination, during invalidation proceedings, the patentee is allowed to make amendments to the claims but the specific manners of amendment are generally limited only to deletion of a claim, combination of claims, and deletion of a technical solution contained in a claim, wherein “deletion of a technical solution” means to remove one or more technical solutions from several parallel technical solutions defined in a claim. So, in the present case, the key issue is whether the amendments to the definitions of R4 and R5 should be regarded as a kind of “deletion of a technical solution”.
The different attitudes toward such amendments reflect the long-standing debate over the nature of Markush claims – whether a Markush claim only defines a single generic technical solution or is just a collection or list of many alternative technical solutions. As illustrated in the present case, when relating to a chemical compound, a Markush claim usually contains a general formula with various substituents at different sites of the molecule, wherein each substituent is variable and has many alternatives (options). By varying the substituents, a Markush claim may cover a lot of different compounds. However, it is controversial whether such a Markush claim, in its nature, defines a single general formula covering a lot of compounds or is just a kind of shorthand or abbreviation for a list of different compounds.
The Court has expressly stated their support to the latter opinion in the judgment, which is excerpted as follows:
“Both the first-instance court and the PRB hold that deletions of certain elements from Markush claims is not deletion of technical solution from multiple alternative technical solutions, and therefore does not conform to Rule 68 of the Implementing Regulations. This opinion in fact means regarding a Markush claim as a single generic technical solution and precludes such deletions during an invalidation proceeding. This court does NOT agree with such an opinion.”
The Court has also confirmed that “during both the examination procedure and invalidation proceeding, the applicant/patentee should be allowed to delete certain alternatives for certain variables from Markush claims, which deletion is a kind of deletion of technical solution from multiple parallel technical solutions”.
By doing so, the Court officially clarifies that Markush claims should be interpreted as a collection of a plurality of parallel alternative technical solutions instead of a single generic technical solution. Accordingly, during examination and invalidation proceedings, it should be allowed to delete any options of any variables from a Markush claim.
However, the judgment has not calmed down the hot debate over Markush claims. For example, an influential Chinese academic journal published a paper by two senior examiners of the PRB directly doubting the judgment of the Court (Li Yue and Ni Xiaohong, China Patents & Trademarks, No. 1, 2015, P. 56-71).
Although there are different opinions about the judgment, the author agrees with the Court in this regard.
1. First, it seems the PRB in fact adopted inconsistent criteria in allowing the removal of “or esters thereof” and rejecting the deletion of some options from definitions of R4 and R5 in the present case.
It is well known that “a compound or ester thereof” just represents a compound with a general formula, wherein a substituent at a certain molecular site may be either -OH or -OOR (R is e.g. an alkyl group). So, the removal of “or ester thereof” only represents the removal of some alternative substituents at a certain site. Meanwhile, the removal of options for certain substituents in a Markush claim also means the removal of some alternative substituents at a certain site. So, in the present case, there is no substantial difference between the removal of “or esters thereof” and the deletion of some options from definitions of R4 and R5, and it seems not appropriate to allow one kind of amendment while rejecting another.
In contrast, the Court seems to adopt more uniform standard on the amendments.
2. Li Yue and Ni Xiaohong, supra, argue that interpreting a Markush claim as a collection of alternative technical solutions may be not compatible with some well-recognized patent practice. For example, both USPTO and SIPO allow granting particular compounds within the scope of a prior Markush claim, which is known as “selection invention” in China. Such a practice implies that particular compounds within an allowed Markush claim are still deemed to be novel. However, if the Markush claim is interpreted to be equivalent to a list of a plurality of particular compounds in parallel, any particular compounds within the scope of the Markush claim would be rendered non-novel. This seems to be a paradox.
The above argument is not persuasive for overlooking special requirements for the disclosure of a chemical compound. For the novelty of a chemical compound, the Guidelines for Examination has the following stipulations: “For a compound claimed in an application, if it has been mentioned in a prior art reference document, it is deduced that the compound does not possess novelty” and “the word ‘mention’ means to clearly define or explain the compound by the chemical name, the molecular formula (or structural formula), and the physical/chemical parameter (s) or the manufacturing process (including the raw materials to be used).” That is to say, although a Markush claim can be interpreted to list every and all compounds covered by a formula, it does not mean that all of these compounds have been adequately disclosed and thus such a Markush claim may not destroy the novelty of each compound. In fact, the PRB adopted similar criteria in the determination of novelty in many of their own cases, which assert that a prior art general formula cannot anticipate particular compounds within its scope unless the particular compounds were actually prepared and/or identified in the prior art.
That is to say, a Markush claim can be interpreted as listing each compound within its scope, but it does not means that each compound has been sufficiently disclosed. So, interpretation of a Markush claim as a group of technical solutions does not preclude the practice of “selection invention”.
3. Li Yue and Ni Xiaohong, supra, also argue that interpreting a Markush claim as a collection of alternative technical solutions may have some potentially adverse influences and may be detrimental to the public’s interests. In particular, “allowing such deletion directly renders the future scope of protection of a patent unpredictable, or even results in an unacceptable scope” because:
- “When a patentee is faced with an invalidation request, a new mid-scope is certain to be created in the claims after an option of any variable is deleted”;
- “once [a Markush claim] is allowed to delete any option, the ways of deleting options to correct the same flaw in the claim can be quite varied and unpredictable, which is likely to render the scope of protection uncertain and unpredictable after amendment”, and
- as “invalidation of one patent right can be repeatedly requested”, “it is not difficult to imagine that an independent claim with some options deleted several times will an ever standing ‘hornet’s nest’ full of holes in it”.
In contrast, the judgment of the Court describes the disadvantages of interpreting a Markush claim as a generic technical solution and not allowing deletion of some alternatives from the claim. The Court states:
“It is well known that during the drafting and examination of patent applications, both the applicant and the examiner can only conduct a prior art search within a certain scope. Due to the infinity of the prior art, no one can make an exhaustive prior art search. If a granted Markush claim is deemed as a single generic technical solution and deletion of certain alternatives for certain variables is not allowable, then the patentee would find it very difficult to withstand other’s attack on the validity of the patent. It is impossible for the patentee to learn or predict whether there was a specific technical solution falling within the granted claim before the filing date, then it would be very easy to invalidate the patent right, rendering the existence of Markush claims meaningless.”
It seems each opinion has its own merits and reasons. The PRB is in favor of the public while the Court is in favor of the patentee. One of the underlying principles for the modern patent system is to establish a balance between the patentee’s legal right and the public’s interests. In this sense, the opinion of the Court seems to be more justified.
What the PRB worries about is the following scenario: after a Markush claim is granted, someone finds a prior art compound falling within the scope and challenges the validity of the Markush claim, then the patentee amends the claim to circumvent the prior art compound, then once again someone finds a new prior art compound within the scope of the amended claim, and then the claim is amended again, and such a process is repeated again and again. It can be imagined that the possibility of repeatedly finding one compound after another within the scope of an allowed Markush claim should be very low. Instead, just finding one prior art compound within the scope of the Markush claim may be high.
So, what the Court concerns is a high probability event, while the PRB is focused on a very small probability event. From the view of probability theory, the Court’s opinion is more justified while the PRB’s opinion is less meaningful.
4. According to the Court, although it is allowed to delete certain elements from a Markush claim, there is an exception for such amendments, as stated in the judgment:
“In view of the fact that not all of the compounds covered by a granted Markush claim have been actually prepared, the boundary for the allowable amendments is not to make the amended claim become particular compounds not disclosed in the description; otherwise there would be no room for a selection invention toward a Markush claim.”
That is to say, it is allowed to narrow down a Markush claim into particular compounds disclosed in the description, but not allowed to narrow down a Markush claim into particular compounds not disclosed in the description. In fact, the Court deems the latter kind of amendment as an exception.
However, the author has different opinions on this and it seems unnecessary to treat such an amendment as an exception. As the Court confirms, a Markush claim relating to compounds should be interpreted as a list of a lot of compounds, each of which is alternative to another. By “alternative”, it means there is no need to distinguish the compounds disclosed in the description from those not disclosed and treat them in different ways. If a Markush claim is interpreted as a list of many compounds, it should be allowed to delete any compounds and leave any compounds without any discrimination. Furthermore, as discussed above, narrowing down a Markush claim into specific compounds not disclosed in the description will not destroy the novelty of these compounds, and thus will still leave room for selection inventions. So, it seems not necessary to draw a boundary for the allowable amendments to Markush claims.
It may remain controversial whether narrowing down a Markush claim into specific compounds not disclosed in the description goes beyond the original disclosure. In the author’s opinion, if a Markush claim should be interpreted as a collection of parallel technical solutions, such an amendment does not bring any substantially new subject matter and thus does not go beyond the original disclosure.
For the above reasons, the author agrees that a Markush claim should be interpreted as a collection of a plurality of parallel alternative technical solutions instead of a single generic technical solution, and it should be allowed to delete any alternative technical solution from a Markush claim.
- Inventive step of Markush Claims
As the Court interprets a Markush claim as a collection of several alternative technical solutions, the inventive step of a Markush claims should also be determined by way of comparing an individual technical solution covered by the claim with the prior art instead of regarding the claim as a whole. In particular, the Court states that the inventive step of a Markush claim should be evaluated in the following manner:
“When a Markush claim relates to chemical compounds, such a claim usually covers thousands of specific compounds and thus has a very broad scope. In this case, it requires that each specific compound covered by the claim should exhibit unexpected technical effects or has unexpected use as compared with a prior art specific compound with similar structure so as to render the claim inventive. In the determination of inventive step involving comparison of different Markush claims, screening should be first made within the scopes of the different Markush claims in order to select some specific compounds having structures as similar as possible to each other, and then a comparison of technical effects should be made. As long as there is a specific compound falling within a Markush claim which does not produce any expected technical effects and has no unexpected use as compared with a specific prior art compound with similar structure, it should be determined that such a Markush claim does not involve an inventive step.”
In other words, in the determination of inventive step involving Markush claims, the comparison should be made on a compound-to-compound basis instead of formula-to-formula basis. For example, in the present case, the Court adopted the above methodology to determine the inventive step of Claim 1 of ‘347 Patent. In particular, the Court has found that Examples 10, 17, 19, 22-24, 50 and 69 of ‘347 Patent have structures very similar to Example 329 of EP0324377A2. So, the eight compounds are identified as specific examples to be compared with Example 329 of EP0324377A2. A comparison shows that, as compared with Example 329, four of these eight compounds exhibit superior technical effects while the other four exhibit inferior technical effects. Such a result shows that there is at least one compound within the Markush claim, which does not produce any expected technical effects and has no unexpected use as compared with a specific prior art compound with similar structure, and thus Claim 1 is not inventive.
Obviously, the above methodology set forth by the Court is consistent with interpretation of a Markush claim into a collection of a plurality of parallel alternative technical solutions. Unfortunately, the Court does mention how to determine inventive step of a Markush claims when a compound-to-compound comparison is not feasible, for example, in case it is not possible to find similar compounds for comparison or there are no experimental data available for a compound-to-compound comparison.
Previously, during the examination of inventive step of Markush claims, Chinese examiners usually compared the overall similarity between two general formulae in different Markush claims and judged whether there is any motivation in the prior art to modify one general formula into the other. According to the Court, this methodology is not correct, and whenever it is possible, a comparison should be made on a compound-to-compound basis. However, it can be expected that examiners may still tend to follow the old-style methodology because it is relatively simple and easy and the new methodology sometimes is not feasible. So, the present case may not affect the practice of patent examination significantly. However, the new methodology provides a new weapon for opponents in challenging patents having Markush claims.
Conclusion and recommendations
A Markush claims is in fact a hybrid of a generalized concept and a list of alternatives. Whether or not to allow the deletion of alternatives is a controversial issue. There may be no absolutely correct answer. Since all of the PRB’s decisions are to be subjected to judicial review, the PRB will have to follow the standard established by the Beijing High Court. So, although the debate will continue, applicants/patentees can expect that amendments to Markush claims are less restricted and patent challengers can expect that finding of a prior art compound with similar structure will be helpful in invalidation proceedings.
In view of the opinion of the Beijing High Court, the importance of dependent claims seems to decrease. However, it is still recommended to draft the claims into the traditional multi-layered upside-down pyramid architecture when drafting an application. Because China’s Supreme Court has not voiced an opinion on this issue, the possibility that the Supreme Court has a different opinion cannot be excluded.