On April 8, 2021, the Korean Supreme Court issued a landmark decision upholding the validity of a selection invention patent covering apixaban (the active ingredient in BMS' Eliquis® product), reversing the lower Patent Court decision and redefining the standard for patentability of selection inventions in Korea.

Background

In Korean practice, a "selection invention" refers to an invention where all or part of the constitutional elements of the invention are species of a genus in the prior art. Until now, the standards for assessing the patentability of such inventions have been governed by a series of Supreme Court decisions from about 20 years ago, which imposed the below requirements.

• The prior art must not disclose the specific concept constituting the selection invention (novelty). 
• All specific concepts in the selection invention must have a qualitatively different or quantitatively significant effect (inventiveness). 
• In order for such effects to be considered in assessing the inventiveness, the patent as filed must provide a "specific description" for a qualitatively different effect, or a "quantitative description" (e.g., data) for a quantitatively significant effect.

The above criteria have long been criticized by legal observers as being unduly strict compared to the criteria used for evaluating other inventions, and in conflict with the approach of most other leading patent jurisdictions for selection inventions. In particular, many observers have criticized basing the inventiveness of a selection invention solely on its "remarkable effects," while ignoring its constitutional difficulty (i.e., the difficulty of deriving the features of the invention from the prior art). Others questioned why the quantitative data required to support the selection invention's effects could only come from the patent specification as filed.

Conflicting Rulings in the Lower Courts

In this case, multiple generics filed invalidation actions at the Intellectual Property Trial and Appeal Board (IPTAB) against the patent, while BMS filed a preliminary injunction ("PI") action at the District Court against the generics on the basis of patent infringement. Unusually, the District Court and the Patent Court (which heard the appeals of both the PI action and the invalidation actions) reached different conclusions regarding the inventiveness of the patent. 

Despite the patent at issue being a selection invention, the District Court upheld inventiveness by reviewing both whether constitutional difficulty and superior effects existed for the invention, holding that (1) it was unreasonable to look at only superior effects to determine the inventiveness of a selection invention, and (2) where a selection invention would have been extremely difficult to select from the prior art, constitutional difficulty alone can support inventiveness even in the absence of superior effects.

The Patent Court reached the opposite conclusion and held that the selection invention lacked inventiveness given the strict patentability standards for such inventions. However, the Patent Court indicated the strict current criteria could be relaxed where (1) the prior art provides a description or suggestion teaching away from the selection invention OR (2) the prior art does not disclose details that can be "generalized to the genus concept of the prior art (which can then be expanded to the species concept of the selection invention)." Nevertheless, the Patent Court determined that the patent at issue did not qualify for either exception.

Despite the differences in their reasoning and conclusions, both the District Court and the Patent Court seemed to recognize problems in the existing approach to selection inventions, and separately tried to define new fairer criteria that would still work within the boundaries of Supreme Court case law.

The Supreme Court's Decision and Implications

As a first step, the Supreme Court held that selection inventions should be reviewed under the same general inventiveness criteria as all other inventions. This was extremely important, since this confirmed that both constitutional difficulty and remarkable effects should be considered for the patentability of selection inventions. This also meant that any remarkable effects could be considered to support inventiveness as long as the effect broadly could be recognized or inferred from the patent's description (i.e., rejecting the requirement that the description must be "specific" or "quantitative" depending on the nature of the effect being claimed) and could be supported with additional data prepared after the filing date.

Using the above approach, the Court first determined that the prior art in this case disclosed a very broad general formula covering apixaban but did not disclose or provide a motivation to develop its core structure or substituents. Further, the Court found that the patent provided a general description of apixaban's improved effects, and the post-filing data that was submitted supported such effects. The Court thus implied that the "specific description" or "quantitative description" (e.g., data) requirement is unduly strict and not always necessary to support a selection invention's remarkable effects. Based on the above, the Court concluded that the patent possessed both constitutional difficulty and improved effects, which rendered it inventive over the prior art genus patent.

The decision has been welcomed by many legal observers as substantially more consistent with other major patent jurisdictions, and is expected to have a significant impact on the patentability and enforcement of selection inventions in Korea, potentially affecting the pharmaceutical sector as well as many other industries.