Supreme Court upholds validity of selection invention patent for first time

Introduction
In Eli Lilly v Hanmi (Supreme Court, 2010Hu3424, 23rd August 2012) the Supreme Court upheld the validity of Eli Lilly's patent for a selection invention in relation to anti-psychotic drug Zyprexa. This is the first case in Korea in which a patent for a selection invention has been held valid in an invalidation action.

In previous rulings (eg, Supreme Court Cases 2008Hu736 (decided on 15th October 2009) and 2008Hu3469 (decided on 25th March 2010)) the court has imposed very high and strict patentability requirements for a selection invention, as follows:

• Novelty requirement - a selection invention should not be specifically disclosed in the prior art or should not be recognisable from the prior art by a person skilled in the art.
• Inventiveness requirement - the selection invention should provide either qualitatively different effects or quantitatively much superior effects.
• Description requirement - such effects should be clearly described in the specification, as originally filed. These requirements are met only if such effects are described in detail in the original specification so as to confirm the different effects from the descriptions (or, if qualitatively the same but superior effects, described in a quantitative manner (eg, three times higher efficacy)).

Due to such strict requirements, until the present case, all of the selection invention patents challenged in invalidation actions were held invalid.

Facts
Eli Lilly's patent (KR 195566) relates to a single compound, 2-methyl-10-(4-methyl-1-piperazinyl)-4H-thieno[2,3-b][1,5]benzodiazepine (later known by its generic name, olanzapine), which is the active pharmaceutical ingredient of Zyprexa. One of the prior art references cited by Hanmi described a large number of compounds in a general chemical formula, which encompasses olanzapine but does not specifically disclose the compound. Thus, the present invention for olanzapine was considered as a selection invention under Korean patent law.

Decision
The present patent for olanzapine was held valid by the Intellectual Property Tribunal. However, on appeal, it was held invalid by the Patent Court for lack of inventiveness. Reversing the Patent Court's decision, the Supreme Court held the present invention to be clearly inventive over the cited reference.

The present invention was considered to be novel by both the tribunal and the Patent Court, since:

• It was not specifically disclosed in the cited reference.
• It was not included in various preferred compound groups.
• There was no indication or suggestion that olanzapine would be a good candidate compound.

Among the compounds specifically described in the cited reference, the structurally most similar compound to olanzapine was 2-ethyl-10-(4-methyl-1-piperazinyl)-4H-thieno[2,3-b][1,5]benzodiazepine (referred to as "ethyl olanzapine", for ease of reference). Thus, to determine inventiveness, the essential issue in dispute was whether olanzapine had either qualitatively different effects or quantitatively much superior effects in comparison to ethyl olanzapine. In this regard, the patent specification stated:

"In dog toxicity studies with a closely analogous compound (ethyl olanzapine), at a dosage of 8 mg/kg, it was observed that four out of eight dogs showed a significant rise in cholesterol levels, whereas the compound of the present invention (olanzapine) did not show any rise in cholesterol levels."

The tribunal recognised the inventiveness of the olanzapine invention, based on the above effects described in the specification and additional supporting materials submitted in the case (including the dog tests conducted in the related US patent litigation).

However, the Patent Court considered that such effects (ie, no rise in cholesterol levels) were not remarkably superior to those of ethyl olanzapine. The court did not see such cholesterol-related effects as being qualitatively different, stating that they are often found as side effects of drugs. Further, the court denied the remarkableness of such effects by improperly comparing the animal test results conducted by different parties in the US patent litigation, rather than comparing the test group results with the control group test results.

In contrast, the Supreme Court held that such cholesterol-related effects were qualitatively different effects, since they were not disclosed in the cited reference and a person skilled in the art could not anticipate from the cited reference that ethyl olanzapine would have such effects. Further, the Supreme Court saw the descriptions on the dog toxicity studies in the specification as being detailed descriptions from which such qualitatively different effects of olanzapine were clearly evident compared to ethyl olanzapine.

In addition, the Supreme Court reiterated its previous holding that where a selection invention has multiple working effects, the selection invention can be recognised as having qualitatively different or quantitatively remarkable effects compared to a prior art even if only a part (and not all) of the effects of the selection invention have been recognised as being qualitatively different or quantitatively remarkable compared to the prior art (see Supreme Court, 2002Hu1935, 24th October 2003). Thus, it concluded that the present invention was clearly inventive, since it had a reduced side effect of cholesterol level increase compared to ethyl olanzapine, which is a qualitatively different effect among the various effects of olanzapine.

Comment
This is the first case in Korean history in which a selection invention patent has been held valid by the Supreme Court. Further, the court has clarified for the first time what constitutes a qualitatively different effect.

This article was first published by the International Law Office (www.internationallawoffice.com).