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China’s SPC issues landmark drug patent ruling

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Xiaohui Wu, Yuming Wang and Jianhui Li of Wanhuida Intellectual Property discuss the Supreme People’s Court’s first decision in parallel civil and administrative proceedings involving a chiral drug patent

On December 19 2021, the Intellectual Property Court of the Supreme People’s Court (SPC) published its final decisions on the first parallel civil and administrative proceedings involving a medical use patent for a chiral drug. The cases, which were heard in public on April 25 2021, are highly significant.

In these cases, the SPC sheds light on several important issues including: assessment of technical teaching of the prior art, inventiveness parameters for optical isomers and medical use invention, interpretation on the scope of protection of medical use claims, the prior art defence and the prior use defence.

The case relates to two patents: 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 petitioners challenging the validity of its inventions in two administrative proceedings and infringers appealing two parallel patent infringement civil decisions. The battle ended with the patentee’s victory.

Administrative proceeding

In the administrative proceeding, the petitioner sought to reverse the CNIPA’s invalidation decisions numbered 38074 and 38076. The trial court, the Beijing Intellectual Property Court, found on June 10 2020 that the patents at issue were devoid of inventive step and should be invalidated. The CNIPA and the patentee both appealed to the SPC’s Intellectual Property Court.

The patentee asserted that the trial court erred in its finding and failed to follow the three-step approach in the assessment of inventiveness. It 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 for assessing inventiveness and the legislative intention regarding medical use inventions.

“The SPC sheds light on several important issues including assessment of technical teaching of the prior art, inventiveness parameters for optical isomers and medical use invention.”

The descriptions of the patents at issue state that the reduction of neurotoxicity is the technical effect achieved by the claimed technical solutions, and this should 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. These facts corroborate 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 of appeal affirmed that prior to the application date of the contested 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 two pieces of evidence cited and the 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 failed to follow the three-step approach and failed to base its findings of technical teaching on the entirety of the prior art. Therefore, the decisions were erroneous and should be corrected.

The SPC expatiated on the metrics in ascertaining inventiveness of a medical use patent: where the person skilled in the art has no "reasonable expectation of success” as to the medical use invention of a known compound, the said invention should be deemed inventive, provided that the medical use or efficacy is achieved by utilising the newly discovered properties of the compound and produces beneficial technical effects that were unforeseeable to the person skilled in the art, 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.

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

The patent infringement proceeding was quite straightforward. In decisions dated May 22 2020, the Shanghai Intellectual Property Court affirmed infringement, ordered cessation and monetary indemnity of RMB 800,000 ($125,000) (inclusive of reasonable costs). The 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, whose patentability lies 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 1 of the patents at issue, there was no need to revisit that matter in the infringement comparison and examination of the prior art defence.

Regarding the prior art defence, the SPC found that there were different scenarios as to the biological activities of chiral drugs. One piece of evidence cited by the accused infringer disclosed the activity of ornidazole and it transpired that levo-ornidazole and right-ornidazole could be obtained through 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 onward, the manufacturing of levo-ornidazole by the accused infringer was merely on a laboratory scale for about three years. Moreover, the implementing entity introduced in the evidence of the prior use defence by the accused infringer was not a stakeholder in the case, and 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 upheld the decisions of the Shanghai IP Court based on this reasoning.

A welcome move

It is 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 are adjudicated by the same court in a synchronised manner. This provides clarity and predictability to both sides of disputes.


Xiaohui Wu

Senior patent counsel

Wanhuida Intellectual Property


Xiaohui Wu is a senior patent counsel at Wanhuida Intellectual Property. Her areas of technical expertise are biology, pharmaceuticals, chemicals, and chemical engineering.

Xiaohui’s experience as the R&D project director at a local pharmaceutical company has equipped her with a better understanding and anticipation of the needs of the firm’s biopharma clients in respect of patent prosecution, enforcement and dispute resolution field.

Xiaohui was one of the lead counsels that helped a pharmaceutical multinational corporation enforce its invention patents against the infringers offering to sell products exploiting the client’s patents in two cases, which are selected as one of the National Ten Exemplary Patent Administrative Enforcement Cases in 2019 and 2018 by the China National Intellectual Property Administration.


Yuming Wang


Wanhuida Intellectual Property


Wang Yuming is a partner and attorney-at-law at Wanhuida Intellectual Property. His practice primarily focuses on intellectual property law.

Yuming has extensive experience in litigating trademark, unfair competition, patent and IP-related contractual matters. He has been defending his clients’ IP interests all the way up to China’s Supreme People’s Court.

Honing his expertise in over 300 lawsuits, Yuming has served as lead counsel in landmark cases, which are selected as exemplary cases by the Supreme People’s Court and the Beijing High Court. He was listed as a rising star by MIP IP Star in 2021.


Jianhui Li


Wanhuida Intellectual Property


Jianhui Li is a paralegal at Wanhuida Intellectual Property. Her areas of technical expertise are biology, pharmaceuticals, chemicals and biomedical engineering.

Jianhui assists the firm’s senior patent practitioners in patent infringement, patent validity analysis, free-to-operate and other patent legal affairs for a few multinational biological and pharmaceutical corporations both at home and abroad.

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