(Baxalta Inc. and Baxalta GmbH v. Chugai Pharmaceutical Co., Ltd.)

[Tokyo Local District Court Judgment dated March 28, 2018 (2016 (Wa) No. 11475)

1. Point of the judgment

   In this case, the scope of the claimed invention is limited based on the effects verified by working examples described in the patent specification.

   When a claim is described as “means plus function” claim, its interpretation becomes an issue. In the U.S., according to U.S. Patent Law Section 112, paragraph 6, when the claim is a means plus function claim, the scope of the invention is limited only to the structures recited in the patent specification and equivalents thereof.

   Whereas in Japan, the Patent Law has the prescriptions that the scope of a patent invention shall be determined based on the claim recitations attached to the application (Japanese Patent Law Article 70, paragraph 1), and the meaning of each term used in the claims shall be interpreted in consideration of the statements in the specification and drawings attached to the application (Japanese Patent Law Article 70, paragraph 2). However, there are no rules related to means plus function claims in Japanese Patent Law and the interpretation thereof is left to the judge’s discretion on the premise of precedents.

    This case is a dispute over the claimed scope of Patent No. 4313531, which is a patent for an antibody drug for treatment of hemophilia. The Court took the statements of working examples into consideration and construed the wording “increases procoagulation activity” recited in the claim that only the one having the ratio to negative control exceeding about 2.0 can be included in the claimed technical scope, and found that the defendant’s product does not fall within the scope.

Section 1. Summary of the case

1. Parties concerned

   Plaintiff: Baxalta Inc.

   Plaintiff: Baxalta GmbH

     (The plaintiffs jointly own Patent No. 4313531)

   Defendant: Chugai Pharmaceutical Co., Ltd.

2. Invention in this case (Patent No. 4313531)

   The invention recited in claim 1 of the present patent is as follows (underline added by the author):

   1A   An antibody or an antibody derivative against factor IX or factor Xa;

   1B   which increases procoagulation activity;

   1C   (except for an antibody clone AHIX-5041 manufactured by Haematologic Technologies Inc., an antibody clone HIX-1 manufactured by SIGMA-ALDRICH Inc., an antibody clone ES N-2 manufactured by American Diagnostica Inc., an antibody clone ESN-3 manufactured by American Diagnostica Inc., and antibody derivatives thereof).

3. Summary of the judgment

   Regarding the meaning of the recitation “increases procoagulation activity”, there is no definition of the phrase in the specification of the present invention and it is itself the purpose of the invention, which is to “provide a preparation for the treatment of blood coagulation disorders” (paragraph [0010]). Furthermore, the phrase merely expresses the function or effect of an antibody or an antibody derivative and does not clarify any specific configuration required to achieve the purpose or the effect of the invention.

... When a claim is written in abstractive and functional expressions, the claimed scope cannot be clarified only by its recitation. In addition to the recitations in the claim, the statements in the specification and the drawings shall be taken into consideration, and the technical scope of the invention should be determined based on the technical idea shown in the specific configuration disclosed therein. However, this does not mean that the scope of the patent invention be limited to concrete working examples. Any configuration that could be implemented by a person skilled in the art in view of the statements in the specification and the drawings should be recognized as being included in the scope of the patent invention.

   Regarding the degree of “increases procoagulant activity”, it is not evaluated as “increases procoagulant activity” when the ratio to the negative control in the chromogenic assay is about 1.7 (for example, ... the ratio of antibody 198/API to negative control is about 1.7, but 190/API does not exert procoagulant activity ...) or about 2 (... the ratio of A1/5 to negative control is about 2, but there is no significant procoagulant activity assessed) in the present specification. Thus, “increases procoagulant activity” is equivalent to understanding that at least the ratio with the negative control must be of more than about 2. Then, those with little increase in procoagulant activity are not evaluated as “increases procoagulant activity”. The degree of increasing must be substantial. It should be therefore recognized that the phrase “increases procoagulant activity” requires a ratio thereof to negative control of at least more than about 2.

   The ratio of monospecific antibody (Qhomo) (author’s comment: an antibody on which the defendant’s product is based) constituted of the left and right arms each binding to factor IXa to the negative control was 1.35 to 1.48 as measured by a chromogenic assay kit. Thus, it cannot be said that Qhomo is a monospecific antibody that substantially increases the procoagulant activity of factor IXa.

Section 2. Practical Guidance

   The present case is an issue over an interpretation of a means plus function expression written in the claims.

   The present decision states that, in the set criteria, “However, this does not mean that the scope of the patent invention be limited to concrete working examples. Any configuration that could be implemented by a person skilled in the art in view of the statements in the specification and the drawings should be recognized as being included in the scope of the patent invention”. In other words, although the working examples of the invention are taken into consideration in order to interpret the meanings of the means plus function expression in the present case, this does not necessarily mean that the claims are limited to the configuration of the working examples. This is consistent with the trend of the precedents in Japanese court decisions.

   Next, regarding the meanings of the means plus function expressions, the present decision states “it is not evaluated as ‘increases procoagulant activity’ when the ratio to the negative control in the chromogenic assay is about 1.7 ... Thus, ‘increases procoagulant activity’ is equivalent to understanding that at least the ratio with the negative control must be of more than about 2”. This means that the scope of claims stipulated in a manner of a means plus function expression is limited to the scope of effects that are verified by working examples.

   In general, when effects verified by working examples are irrelevant to the claimed features, it does not necessarily mean that the scope of the claim is limited to the embodiments whose effects are validated by the working examples and the equivalents thereof. Also, since the term “procoagulant activity” is a technical term, the meaning of the term can be understood based on the technical common knowledge of a person skilled in the art obtained from documents, such as dictionaries or technical papers, other than the specification of the invention. If the term was understood in that way, it is unlikely that the invention was considered to be limited to the one having the ratio against negative control exceeding about 2.0.

   However, in the present case, the claims are interpreted, on the basis of the means plus function expression in the claims, to be limited only to the embodiments whose effects are validated by working examples and equivalents thereof. For inventions whose scope is expected to be substantially narrowed down if the invention is determined by the structure (often in cases of pioneer inventions in medical field), one cannot help but consider limiting the invention by a means plus function (i.e. the effects of the invention). In such cases, one should be careful and understand in drafting that there are possibilities that the invention may be limited not only to the “means for solving the problems described in working examples” but also to the scope of “effects verified by the working examples.”