Lee International

A selection invention refers to an invention essentially comprising a species, which is selected from a broad genus in the prior art. Until now, the Supreme Court has repeatedly held that a selection invention is acknowledged to have an inventive step only if it produces a qualitatively different or quantitatively remarkable effect in comparison to prior art and if the specification for the selection invention specifically describes such effect. As such, it was the Korean patent practice that in determining the inventive step of a selection invention, only the effect of the invention was considered without examining the technical difficulty in conceiving the invention.

Recently, however, the Supreme Court held that the inventive step of a selection invention should be determined based on both the technical difficulty and the remarkable effect of the invention (Supreme Court Case No. 2016 Hu 10609 issued on April 8, 2021). That is, the Supreme Court held that the inventive step of a selection invention should be determined under the same criteria as non-selection inventions.

1. Case History

Some Korean generic companies filed an invalidation trial against an apixaban patent of Bristol-Myers Squibb (BMS), asserting that the patent lacks an inventive step as a selection invention. On February 28, 2018, the Intellectual Property Trial and Appeal Board (IPTAB) issued a decision denying the inventive step of the patent. On June 27, 2018, however, in the preliminary injunction action brought by BMS against the Korean generic companies, the Seoul Central District Court issued a decision contrary to the IPTAB’s decision, acknowledging the inventive step of the BMS patent and granting a preliminary injunction against the generic companies (2018 Kahap 20784). Subsequently, in the appeal of the IPTAB’s invalidation decision, the Patent Court maintained the IPTAB decision on March 29, 2019 (2018 Heo 2717). Since conflicting decisions were issued for the same patent, the Korean pharmaceutical industry has been highly interested in how the Supreme Court, which is the highest court, would determine the inventive step of this patent.

2. Supreme Court’s Determination

On April 8, 2021, the Supreme Court ruled as below.

The apixaban patent of Bristol-Myers Squibb (BMS) is a selection invention. In determining the technical difficulty in conceiving the selection invention, the following matters should be considered: the number of species compounds which theoretically fall within the chemical formula and substituents in a Markush group of the genus prior art; any reason, motivation or implication for one of ordinary skill in the art to preferentially or easily select a particular compound or a particular substituent among the compounds in the Markush group of the prior art; and any structural similarity between the compound specifically disclosed in the prior art and the compound of the selection invention.

In the previous Supreme Court decisions, the inventive step of a selection invention was determined based only on whether the effect of the selection invention is remarkable, without considering the technical difficulty in conceiving the invention. However, this does not mean that an inventive step of a selection inventions should be determined based solely on its remarkable effect without considering the technical difficulty in conceiving the invention. Therefore, the inventive step of a selection invention should be determined under the same criteria as non-selection inventions, i.e., based on unique problem-solving principles and the difficulty configuring the components in an invention in its entirety, and a distinctive effect.

In this case, the prior art referenced against the validity of the BMS patent is directed to “Nitrogen Containing Heterobicycles as Factor Xa Inhibitors.” The prior art discloses more than hundreds of millions of theoretical compounds of the Factor Xa Inhibitor according to combinations of 66 types of core structures and various substituents thereto. On the other hand, the BMS patent claims apixaban having a lactam ring among the combinations included in the prior art.

The prior art does not specifically disclose the lactam ring of apixaban in the BMS patent. Apixaban in the BMS patent produces improved inhibitory activity, selectivity, and pharmacokinetics, and shows improved effect in co-administration. That is, the prior art focuses on different compounds having different chemical structures from the BMS patent. Furthermore, the prior art does not provide any reason, motivation or implication to preferentially or easily select the compound of the BMS patent. Thus, undue experimentation would be required for one of ordinary skill in the art to identify optimal combinations of core structures and substituents having technical significance from the prior art to arrive at the patented invention.

In conclusion, since there is technical difficulty in conceiving the BMS patent which produces an improved effect, the BMS patent has an inventive step over the prior art.

3. Significance and Implications

In this Decision, the Supreme Court did not overturn the previous Supreme Court decisions in determining the inventive step of a selection invention, but instead, clarified that the previous Supreme Court decisions should be construed to mean that a selection invention which is not deemed to have technical difficulty can be acknowledged to have an inventive step if it is demonstrated to produce a remarkably superior effect. Accordingly, this Supreme Court Decision is significant in clarifying the criteria for determining the inventive step of a selection invention, which have been often differently interpreted.

In the past, Korea has applied very strict standards for a selection invention by only determining whether the specification of a selection invention clearly describes a qualitatively different or quantitatively remarkable effect over the prior art, without considering the technical difficulty in conceiving the invention. In particular, if an inventor has filed a patent application without recognizing that it may be regarded as a selection invention, it was very difficult to meet such strict description requirements, and thus, it was extremely rare for the selection invention to be acknowledged to have an inventive step. In this Decision, the Supreme Court acknowledged the inventive step of the BMS patent based on the technical difficulty in conceiving the invention, but did not determine whether the BMS patent meets the strict description requirements for the remarkable effect. However, in the Patent Court decision (2018 Heo 2717), the Patent Court has already ruled on the standard of the description requirements for the effect of a selection invention, which are provided in the Korean Intellectual Property Office Examination Guidelines. Thus, it is expected that the same strict description requirements will be applied to determine the inventive step of a selection invention, which is not deemed to have technical difficulty in conception, while relaxed description requirements will be applied for a selection invention, which is acknowledged to have technical difficulty.