In Patent Law, a Markush claim is a special type of claim commonly used in the chemical and
pharmaceutical fields when there are a number of variables in one claim and each variable
has multiple options. Once a compound claimed by a Markush claim is patented, its scope of
protection can extend to all the compounds encompassed therein regardless of their effect.

In China, the Guidelines for Patent Examination 2010 contains provisions regarding the
unification of Markush claims, but are otherwise silent on this subject (Guidelines for Patent Examination 2010, part II, Chapter 10, 8.1 Unity of Markush Claims). The nature of
Markush claims and the criteria for amendments has long been a subject of practical and
theoretical discussion (Invalidation trial for ZL94115915.9, ZL97197460.8).

On the retrial of the “Administrative Judgment No. 41 [2016], Retrial, Administrative
Division, Supreme People’s Court”, following three years of careful deliberation, the
Supreme People’s Court of China finally released a judgement which clarified the nature of
Markush claims and the criteria for amending such claims in invalidation proceedings. This
judgement will likely resolve issues where trial court’s criteria has been different and
provides guidance for judging similar cases in the future.

For details, please check the following PDF.