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Korean Supreme Court Reverses Lower Court Decision and Upholds Validity of Patent on DNA Fragment Mixture and Preparation Method


Kim & Chang’s Intellectual Property Practice successfully defended the validity of a patent on a DNA fragment mixture and its preparation method at the Korean Supreme Court on behalf of Mastelli, an Italian pharmaceutical company, and Pharma Research, a Korean biopharmaceutical company. Kim & Chang’s effective advocacy led the Supreme Court to reverse and remand the previous Patent Court’s decision that invalidated the patent.

The patented inventions in this case were a method of preparing a DNA fragment mixture from fish semen or eggs and the resulting DNA fragment mixture itself. The preparation method comprises a zymolysis process, a sterilization process, and a molecular weight reduction process under specific conditions. The DNA fragment mixture obtained through the preparation method has many uses, including in medicines to treat and heal wounds and in cosmetics to improve wrinkles. 

A Korean pharmaceutical company sought to invalidate the patent at the Intellectual Property Trial and Appeal Board (“IPTAB”), but the IPTAB originally dismissed the petition, ruling that the patent satisfied description requirements and was novel and inventive. On appeal, however, the Patent Court held that several terms in the claims were unclear and that the patented inventions could easily have been conceived by a person of ordinary skill in the art from the combination of asserted prior art references, thereby both failing to meet description requirements and lacking inventiveness.

Kim & Chang took on the case at the Supreme Court level. Pointing to objective evidence showing the technical significance of the patented invention as well as the extent of common knowledge in the art at the priority date, Kim & Chang was able to successfully persuade the Supreme Court that the claims of the patent were clearly stated and satisfied the description requirements. Regarding inventiveness, Kim & Chang proved that the patented invention would not have been easily conceived from prior art references by guiding the court’s attention to the invention’s constitutional differences from the prior art references, as well as the technical significance and the organic combination of steps that make up the claimed method. Crucially, Kim & Chang highlighted how the Patent Court’s mechanical approach to combining the prior art in denying the inventiveness factor clearly exercised hindsight, since there would have been no motivation to combine the references if the technical meaning of each process in the prior art references was considered.

The Supreme Court's decision is significant for several reasons. With respect to description requirements, the court went beyond simply confirming whether there was an explicit definition of each term in the specification, as the Patent Court had done, but went further to review whether a skilled person clearly would have been able to understand the claimed invention from what was stated in the claims. As for the inventiveness factor, the court reemphasized the principle that hindsight is not allowed when determining inventiveness, and then considered the technical significance of each process and their organic combination in the invention before concluding that a skilled person would not have easily combined the cited prior art references at the time of filing.

Due to Kim & Chang's careful analysis of the case and the Patent Court's reasoning, close communication with its clients, and multifaceted strategy based on its extensive experience in litigating significant IP cases, Kim & Chang was able to persuade the Supreme Court to overturn the Patent Court's erroneous analysis and to uphold the validity of the clients' patent.