Administrative proceedings
Patent infringement proceedings


On 19 December 2021 the IP Court of the Supreme People's Court (SPC) rendered the final decisions in the first parallel civil and administrative proceedings involving the medical use invention of a chiral drug. The cases, which were heard in public on 25 April 2021, are of empirical significance. The SPC leveraged these cases to shed light on quite a few issues, including:

  • the assessment of the technical teaching of prior art;
  • inventiveness parameters for optical isomers and medical use inventions;
  • the scope of protection of medical use claims;
  • the prior art defence; and
  • the prior use defence.

The case related to two inventions:

  • ZL200510083517.2, entitled "Use of levo-ornidazole for preparing anti-parasitic infection drug"; and
  • ZL200510068478.9, entitled "Use of levo-ornidazole for preparing anti-anaerobic bacteria infection drug".

The patentee was on the defensive and offensive sides of the court: facing both the petitioners challenging the validity of its inventions in two administrative proceedings and the infringers appealing two parallel patent infringement civil decisions. The battle ended with the patentee's landslide victory.

Administrative proceedings

In the administrative proceedings, the petitioner sought to reverse the China National IP Administration's (CNIPA's) invalidation decisions No. 38074 and No. 38076. On 10 June 2020, the trial court, the Beijing IP Court, found that the patents at issue, which were devoid of inventive steps, should be invalidated. The CNIPA and the patentee both appealed to the SPC's IP Court.

The patentee asserted that the trial court had:

  • erred in its finding;
  • failed to follow the three-step approach in the assessment of inventiveness; and
  • neither addressed the technical problem actually solved by the patents at issue nor factored in the unexpected technical effect of levo-ornidazole in "reducing neurotoxicity".

This contradicted both the methodology in assessing inventiveness and the legislative intention of medical use inventions.

The descriptions of the patents at issue stated that the reduction of neurotoxicity was the technical effect achieved by the claimed technical solutions, which had to be taken into account in ascertaining the technical problems actually solved by the inventions. In the meantime, the prior art disclosed neither the activity nor toxicity of ornidazole enantiomers, let alone provided any guidance in terms of using levo-ornidazole to reduce the neurotoxicity of ornidazole. The aforesaid facts corroborated the non-obviousness of the patents at issue and the unpredictability of the technical effect achieved.

The SPC found the patentee's argument tenable. The Court affirmed that, prior to the application date of the litigious patents, a person skilled in the art would have no motivation to study the toxicity of levo-ornidazole and use it as a single ingredient in drug development, under the teaching of evidence one and two and common knowledge in the art. The technical solutions of the patents at issue were non-obvious to a person skilled in the art. The trial court had failed to follow the three-step approach and had failed to base its findings of technical teaching on the entirety of prior art. Therefore, the decisions were erroneous and had to be corrected.

The SPC detailed the metrics in ascertaining the inventiveness of medical use invention. Where the person skilled in the art has no "reasonable expectation of success" as to the medical use invention of a known compound, such invention should be deemed to be inventive. This is provided that the medical use or efficacy – rather than be readily achieved or predicted from the structure, composition, molecular weight, known physical and chemical properties and the existing use of the compound per se – is achieved by utilising the newly discovered properties of the compound and produces beneficial technical effects that are unforeseeable to the person skilled in the art. Nevertheless, if a conclusion is drawn that the prior art has provided technical inspiration in the context where the prior art merely provides a general research direction in the field or points to contrary technical teaching, without giving clear and explicit technical inspiration as to researching the toxicity of chiral enantiomers, the court risks hindsight and underestimation of the inventiveness of an invention.

Patent infringement proceedings

The patent infringement proceedings were quite straightforward. On 22 May 2020, the Shanghai IP Court affirmed infringement and ordered cessation and monetary indemnity of 800,000 Chinese yuan (inclusive of reasonable costs). These decisions were appealed before the SPC.

On the scope of protection of the medical use claims of the known compound, the SPC opined that the patents at issue were inventions deriving from the newly discovered properties of the known compound, the patentability of which lay in the discovery and application of drugs prepared for specific indications, rather than the compound per se. Given that toxicity was not defined in claim one of the patents at issue, there was no need to revisit that matter in the infringement comparison and examination of prior art defence.

Regarding the prior art defence, the SPC found that there were different scenarios as to the biological activities of chiral drugs. Evidence one cited by the accused infringer disclosed the activity of ornidazole, and it transpired that levo-ornidazole and right-ornidazole could be obtained through the resolution of ornidazole. Nevertheless, even in this context, a person skilled in the art would not reasonably predict the biological activity of levo-ornidazole and right-ornidazole. Therefore, the prior art defence could not be established.

With respect to the prior use defence, evidence adduced by the patentee indicated that from the application date of the patents at issue onwards, the manufacturing of levo-ornidazole by the accused infringer was merely on a laboratory scale for about three years. Moreover, the implementing entity, as introduced in the evidence of prior use defence by the accused infringer, was not a stakeholder of the case, and such entity was not associated with the accused infringer. Therefore, the evidence furnished by the accused infringer did not suffice to prove that it had actually produced levo-ornidazole and implemented such for the patented medical use prior to the application date of the patents at issue. The SPC therefore ruled to uphold the decisions of the Shanghai IP Court based on this reasoning.


It was a very welcome move that the SPC consolidated the trial of the administrative and civil proceedings involving the same subject matter to ensure closely correlated proceedings were adjudicated by the same court in a synchronised manner, which provided clarity and predictability to both sides of the disputes.

For further information on this topic please contact Wu Xiaohui, Yuming Wang or Jianhui Li at Wanhuida Intellectual Property by telephone (+86 10 6892 1000) or email ([email protected], [email protected] or [email protected]). The Wanhuida Intellectual Property website can be accessed at

This article was first published by MIP.