Four decisions of the Korean Supreme Court have created problems for those who seek to patent pharmaceutical compositions in Korea. According to these decisions, applicants should include relevant data in the application as filed and cannot provide such data later during prosecution to support the disclosure originally made. These decisions overrule a prior Supreme Court decision of a few years ago which had apparently taken a more lenient position, but which the Korean Patent Office had failed to follow.

In the recent cases, the Supreme Court took the view that for inventions claiming pharmaceutical compositions or medicines, evidence of the likely efficacy of the composition was an essential part of the written description that is required by the statute. The court held that, unless such evidence is present in the application as filed, a person skilled in the art normally does not have sufficient information to readily understand and reproduce the invention. For the description to be complete, there must be sufficient information for the skilled reader to understand the pharmacological mechanism, which the court held would normally require the presence of efficacy data in the application as filed. The only possible exceptions to this noted by the court were "the unusual circumstances" where the pharmacological effect was known in the art or where there was some other "concrete description" that could substitute for the missing efficacy data. The court made no suggestion as to how the latter alternative might be met.

In one of its decisions, the court specifically refused to accept that data filed during prosecution to show the efficacy of the compositions could be used to meet the requirements it set out since an amendment to add such data would "go beyond the scope of the disclosures of the original application."

It therefore appears that, when filing applications in Korea directed to pharmaceutical compositions, one should try to include as much experimental data as possible to avoid the risk of rejection for provision of an inadequate technical disclosure.