Kim & Chang’s Intellectual Property Practice successfully represented Pharmbio Korea Inc. (“Pharmbio Korea”), a domestic pharmaceutical company, in two patent invalidation lawsuits related to bowel cleanser tablets. The team secured victories at both the Intellectual Property Trial and Appeal Board (the “IPTAB”) and the Intellectual Property High Court (the “IP High Court”) by demonstrating that the two patents in question (the “Subject Patents”) could not have been easily developed by a person of ordinary skill in the art based on the prior art inventions.
According to the 2022 National Cancer Registration statistics, colorectal cancer accounted for 11.8% of all cancer cases in Korea, making it the country’s second most common type of cancer. Widely attributed to increasingly Westernized diets, the incidence rate of colorectal cancer among adults aged 20 to 49 reached 12.9 per 100,000 people, raising alarms as the highest rate among the 42 surveyed countries. With the number of colorectal cancer patients in Korea continuing to rise sharply, there is growing emphasis on the prevention and early detection of colorectal cancer, bringing into focus the importance of colonoscopy.
Colonoscopy requires subjects to clear their intestines by consuming a large volume (two to four liters) of a liquid bowel cleanser solution the day before the examination. However, due to the large volume and distinctive, unpleasant taste, 10 to 15% of subjects reportedly fail to complete the dosing regimen. According to the 2018 survey on cancer screening attendance behaviors conducted by the National Cancer Center, bowel cleanser consumption was cited as the top deterrent to undergoing colonoscopy.
Pharmbio Korea has devoted extensive research and efforts into developing a bowel cleanser tablet that overcomes the disadvantages of the liquid bowel cleansers mentioned above. As a result, the company obtained the Subject Patents, which provide colon cleansing effectiveness equivalent to that of the existing products while reducing gastrointestinal side effects.
The technical feature of these patents resides in converting Oral Sulfate Solution (“OSS”), a proven and safe ingredient from traditional liquid cleansers, into a tablet form, reducing the OSS content by up to 10%, and adding simethicone to eliminate intestinal foam, thereby significantly improving patient convenience and reducing side effects such as nausea and vomiting, compared to conventional bowel cleansers.
Pharmbio Korea became the first company worldwide to obtain approval for Orafang Tab., an incrementally modified drug OSS tablet developed based on the Subject Patents, which it obtained from the Ministry of Food and Drug Safety in 2019. Since its market launch, the company has pioneered the new market of bowel cleanser tablets, achieving sales of approximately KRW 20.4 billion in 2024 and expanding its market presence.
Following the release of Orafang Tab. by Pharmbio Korea, bowel cleanser tablets have become a leading trend in the market, spurring several competitors to develop new products in recent years. In particular, one domestic pharmaceutical company (“Company A”) filed patent invalidation actions against the Subject Patents based on four prior patents. However, the IPTAB and the IP High Court dismissed Company A’s claims and held that the Subject Patents have inventiveness over the prior art.
Our firm represented Pharmbio Korea starting from the IPTAB stage. Through thorough technical analysis of the prior art and in-depth legal research on relevant precedents and principles, we demonstrated that the prior art neither clearly disclosed the total dosage of the main ingredients nor specified the tablet form of the formulation. We also successfully argued that selectively extracting certain disclosures from the prior art inventions while ignoring their technical features to deny the inventiveness of the Subject Patents constituted hindsight reasoning. Both the IPTAB and the IP High Court accepted these arguments, ultimately upholding the validity of the Subject Patents.
The IP High Court’s decision is particularly notable as it reaffirmed the legal principle for determining inventiveness, which explains that the technical features must be considered and hindsight analysis is strictly prohibited when examining whether an invention could have been readily derived from the prior art.
In parallel to the invalidation actions, Company A also filed two negative scope confirmation actions, asserting that the bowel cleanser it developed did not fall within the scope of the Subject Patents. However, our firm successfully argued before the IPTAB that Company A’s bowel cleanser directly embodies the essence of the technical concept of the Subject Patents, and thus falls within their scope of claims. As Company A did not appeal, the IPTAB decisions are now final and binding.
