Is the product-by-process claim “dead” in Japan?


After the Supreme Court in Japan handed down a very important judgment in 2015 on the scope of the Product-by-Process (“PBP”) claim, and its doubtful validity concerning the clarity requirement (Pravastatin sodium case, a drug lowering the cholesterol in blood), the authorities commented that the PBP claim is “dead” because almost all PBP claims would be fairly likely to be invalidated according to the Supreme Court’s strict judgment on its patentability. However, very recently, the IP High Court handed down a relevant judgment on this issue, wherein it basically followed the Supreme Court judgment but limited the application of the Supreme Court’s judgment to the “true” PBP claim.

The Supreme Court Judgment (Pravastatin sodium case)

A PBP claim is a product claim, which is described by the process. One main issue in a PBP claim is whether or not it should be considered limited by the described process steps in determining infringement or validity. There had been heated arguments for a long time on how a PBP claim should be interpreted; one is to broadly consider the PBP claim as a product claim, ignoring the described process (“product theory”), and another is to literally consider the PBP claim as limited by the described process steps (“process theory”). The Supreme Court settled this argument in 2015, holding a PBP claim should be interpreted in accordance with the “product theory”. Therefore, as long as the product is the same, the allegedly infringing product falls under the scope of the PBP claim even if it adopts the different process from the one described in the claim. This might sound like it strengthened the protection of PBP claims. However, that is not true. The Supreme Court further held that the PBP claim in general should be invalid on the ground that the invention defined by the PBP claim is unclear (Art. 36(6)(ii) of Japan Patent Act; the invention must be clearly stated in the claims.). The Supreme Court limited the case where PBP claim is considered to be valid, to the very exceptional circumstance where it is, at the priority date, technically impossible to directly specify product’s structure or property in the claim, or too unpractical to spend a lot of money and time to specify the product’s structure or property prior to the filling (“impossible or unpractical circumstance”). According to the judgment, this circumstance would rarely be applied except for very limited technology. One exceptional technology mentioned in the supplementary opinion by the Justice Chiba is a new stem cell created by a new gene manipulation. The complete analysis of cell’s structure or property is almost impossible to carry out before filling, taking into account sever R&D and fast-filling competition with rival companies. In this sense, it is considered that the PBP claim in Japan is “dead”.

The IP High Court Judgment (Rolled Seedling Transplanter Case)

However, on 8th November, 2016, the IP High Court referred to the Supreme Court judgment in another case and further interpreted the clarification requirement of PBP claims. It held that a PBP claim does meet the clarification requirement as long as it is evident from the contents of the patent that the product’s structure or property is clear and the process is described just to clarify the certain part of the product’s structure or property in detail. This IP High Court’s judgment is important because it developed the concept that not all PBP claims are governed by the Supreme Court’s strict judgment, limiting its application only to the “true” PBP claims in which the process is described due to unclear structure or property of the product.

Practical tips on PBP claims

Since the Japan Patent Office used to be tolerant toward granting patents with PBP claims, there are currently many patents with PBP claims. Even if you have one of them, it would be very hard to successfully exercise it in a patent infringement litigation because it would be fairly likely to be invalidated after the Supreme Court’s strict judgment. You should make sure before sending a warning letter to prepare enough evidence to prove “impossible or unpractical circumstance” for the patented invention, or to prove the patented invention is not above-mentioned “true” PBP claim. Unless you can prepare for that, it would be wise not to exercise it.

If you are at the stage of filling a patent application, you should avoid PBP claims, if possible. If you can’t avoid using a PBP claim, you should continue the effort to research and analyze the product’s structure or property even after filling it. If you find something new about the product’s structure or property, then you can utilize the priority right to file the second patent application with clearer structure or property with the purpose of meeting the clarification requirement.


Hirotaka Nonaka

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