The Supreme Court has held that the inventiveness of a substance invention the genus of which was already known in the prior art (‘selection invention’) can be recognized if the constitutional difficulty of the invention is acknowledged under the general inventiveness standard, and thereby upholding inventiveness of the selection invention (Supreme Court Decision Case No. 2019 Hu10609 rendered April 8, 20210.

Ⅰ. Background

A selection invention refers to an invention where all or part of the constitutional elements are species of the genus elements of a prior art. According to the precedents established by the Korean Supreme Court, for selection invention’s inventiveness to be acknowledged, all the species concepts included in a selection invention must have qualitatively different effects from those of the prior art or, in the absence of qualitative difference, a quantitatively significant difference. In this regard, the specification of the selection invention must clearly describe the aforementioned effect. However, it is necessary to include a comparative testing data that can

Specifically confirm the significance of such effect. If the effect is suspicious, the applicant can argue and prove the relevant effect, for example, by submitting specific comparative testing data after the filing date of the patent application. However, in this case, proving the qualitative difference or significance of the effect is required for the selection invention as a whole. As such, it was difficult to have the inventiveness of selection inventions recognized.

Ⅱ. Lower Courts Rulings

In the present case, multiple generics filed invalidation actions with the Intellectual Property Trial and Appeal Board (IPTAB) against Patent A, and the patentee filed a preliminary injunction action with the Seoul Central District Court against the generics based on their infringement of Patent A.

On February 28, 2018, the IPTAB denied the inventiveness of the Patent A based on that the effect of Patent A cannot be deemed qualitatively different from, or quantitatively significant over the prior art, without determination of the constitutional difficulty of Patent A. In other words, the IPTAB denied the inventiveness of Patent A pursuant to the inventiveness standard for selection inventions based on the existing Supreme Court precedents.

However, despite the IPTAB decision above, on June 27, 2018, the Seoul Central District Court recognized the inventiveness in a preliminary injunction action, holding that Patent A indeed has the constitutional difficulty along with the significant effect (Decision No. 2018Kahap 2019 rendered on June 27, 2018).

In this decision, the court questioned the inventiveness standard for selection inventions under the existing Supreme Court precedents, finding that uniform application of the stricter stand of requiring a significant effect even to a selection invention that is admittedly difficult to adopt from the prior art is not reasonable. The above ruling is the first decision presenting the supplementary legal standard that the inventiveness standard for selection inventions is too strict and needs to be relaxed.

Meanwhile, after the above Seoul Central District Court decision, the Patent Court has held as follows in an appeal against the aforementioned IPTAB decision: the strict standard for selection can be relaxed (i) if there is negative disclosure or suggestion teaching away from the patented invention in a prior art, or (ii) in light of the technical level at the time of filing a patent application, if details that can be generalized to the genus concept of a prior art and expanded to the species concept of the patented invention are not disclosed in the prior art that can identify the prior art of a genus concept (Decision No. 2018Heo2717 rendered on March 29, 2019). The Patent Court decision can be deemed as having the same purpose as that of the Seoul Central District Court’s decision, however, the Patent Court denied the inventiveness based on the ground that the relaxed patentability standard for selection inventions should not be applied to Patent A since Paten A does not have any qualitatively different and significant effect.

Ⅲ. The Supreme Court Decision

However, at the appellate trial for the Patent Court decision, the Supreme Court held as follows: (i) the general inventiveness criteria should also be applied when determining the inventiveness of a selection invention; if the constitutional difficulty of a selection invention is recognized, the inventiveness will not be denied even in the absence of a qualitatively different effect or significant effect, and (iii) the strict standard presented in the existing Supreme Court precedents (Decision Case No.2008Hu736 rendered on October 15, 2009, etc.), in particular, the one regarding effect is intended to show that the inventiveness will not be denied if there is a significant effect for the case where it is difficult to have the constitutional difficulty recognized. The Supreme Court further held that inventiveness of a selection invention should not be determined based merely on an effect without examining the constitutional difficulty only because the genus of the patented invention was known in the prior art.

The Supreme Court acknowledged the constitutional difficulty based on the following grounds: “The prior art and the invention of Patent A are different in terms of the compound of interest and structure thereof, and it is hardly deemed that there are any reasons, motivation or suggestion to preferentially or readily select the structure of the invention of Patent A. Thus, a person of ordinary skill in the art would go through repetitive trials and errors of combining numerous alternatives in order to derive the invention of Patent A by finding an optimal combination with technical significance from the prior art.” The Supreme Court also acknowledged the significant effect of the invention of Patent A as there is an improved effect according to the patent specification and experimental data submitted after the filing date. Then, the Supreme Court held that it is hard to deem the inventiveness of Patent A to be denied by the prior art, and reversed and remanded the Patent Court decision.

Ⅳ. Implications for the Supreme Court Decision

This Supreme Court decision accepted the awareness of the problem regarding the inventiveness standard for selective invention under the existing Supreme Court precedents, which was first raised in the Seoul Central District Court decision and followed by the Patent Court decision. Yet, the Supreme Court decision was not issued by an en banc court, and the Supreme Court has not stated to the effect that the precedents contrary to this decision should be abolished.

The standard of recognizing inventiveness of selection invention is very compared to other regular (i.e., non-selection) inventions. For that reason, for a party challenging the validity of a selection invention, the most effective may be to argue the lack of inventiveness of the patented invention, as it will be very difficult for the applicant or the patentee to defend. Under such circumstances, this Supreme Court decision has significance in that it has virtually changed the legal principle for selection inventions through the explicit statement that the inventiveness of the selection inventions should be determined under the same standard as other regular inventions. The recently revised KIPO’s examination guidelines have also presented more relaxed patentability standard for selection inventions, and thus the selection inventions are expected to be better protected.

From Lee & Ko IP

September 2021