In a judgment issued on March 24, 2017, the Supreme Court of Japan ruled on one of the requirements for finding patent infringement under the Doctrine of Equivalents, namely, that the patentee during prosecution did not intentionally exclude the equivalent product/method from the scope of the patent. The Supreme Court held that, even if an equivalent product/method could be easily conceived of by a person skilled in the art at the time of filing of the application but the applicant did cover the equivalent product/method in the claim, that does not necessary mean that the applicant intentionally excluded the equivalent method/product from the scope of the patent (Supreme Court Case No. 2016 (ju) 1242.)
Background
In the so-called Ball Spline judgment issued on February 24, 1998, the Supreme Court of Japan established the requirements for finding patent infringement under the Doctrine of Equivalents. One of the requirements established by the Supreme Court was that, the applicant, during prosecution of the patent, did not intentionally exclude the equivalent product/method from the scope of the patent (the "no intentional exclusion" requirement).
In the current case, Chugai Pharmaceutical ("Chugai") was a co-owner of a patent for a method for manufacturing of Maxacalcitol, and manufactured and sold Oxarol Ointment/Lotion (a drug for treating keratosis) that included Maxacalcitol as an active ingredient. Chugai filed a patent infringement action against certain pharmaceutical companies for selling generic versions of Oxarol. There was no dispute among the parties that the manufacturing method adopted by the defendants did not literally infringe Chugai's patent. Therefore, Chugai asserted infringement under the Doctrine of Equivalents.
In the first instance, the Tokyo District Court found that the defendants' manufacturing method infringed Chugai's patent, and awarded Chugai an injunction. The defendants appealed to the Intellectual Property High Court (the "IP High Court"), which affirmed the Tokyo District Court judgment.
The defendants further appealed the Supreme Court, which decided to hear the case only on the issue of the "no intentional exclusion" clause.
The Supreme Court Judgment
In a judgment issued on March 24, 2017, the Supreme Court made the following ruling:
Even if an equivalent product/method could be easily conceived of by a person skilled in the art at the time of filing of the application, and the applicant did not draft the scope of the patent claim to cover the equivalent product/method, that does not necessary mean that the applicant intentionally excluded the equivalent product/method from the scope of the patent.
However, if the applicant, when viewed objectively, indicated that he recognized that the equivalent feature can replace the claimed feature but intentionally refrained from stating the equivalent feature in the claim (such as when the applicant stated the equivalent feature in the specification as being capable of replacing the claimed feature, but did not claim the equivalent feature), it should be found that the applicant intentionally excluded the equivalent feature from the scope of the patent.
Applying the above general rule, the Supreme Court found that the applicant did not intentionally exclude the equivalent feature from the scope of the patent. Accordingly, the Supreme Court affirmed the IP High Court judgment.
Comments
The Supreme Court judgment held that a mere fact that it was easy for a person skilled in the art to come up with the equivalent product/method (but the applicant did not claim such product/method), does not amount to "intentional exclusion" and therefore does not necessarily result in denial of infringement under the Doctrine of Equivalents. In that sense, the Supreme Court judgment made it easier for patent owners to assert infringement under the Doctrine of Equivalents.
However, if the applicant went on to actually state the equivalent feature in the specification and also stated that it could replace the claimed feature (but did not claim the equivalent feature), that would amount to "intentional exclusion" and would result in denial of patent infringement under the Doctrine of Equivalents. Therefore, applicants should be careful when describing an alternative to the claimed product/method in the specification.
Written by: Mr. Yusuke Inui (Attorney at Law, Patent Attorney)