Recently, we found a case Xitian Zhang vs. CSPC OUYI Pharmaceutical Co., Ltd etc. [Case No: (2009)民提字第84号]. The patent in this case covers resolution of the enantiomers of amlodipine (CN1100038C). The Supreme People’s Court held that:

Although the patent covers a method for the preparation of a new product, the right owner still need to prove that the products made by the accused infringers are identical to the product directly obtained from the patented product, then the accused infringers undertake the burden of proof that the preparation of their products are different from the patented method. As previously stated, the products directly obtained from the method in claim 1 is “a DMSO-d6 solvate of D-tartrate salt of (S)-(−)-amlodipine”, or “a DMSO-d6 solvate of a L-tartrate salt of (R)-(+)-amlodipine”. Xitian Zhang provided evidence to prove that Huasheng and Ouyi manufactured levamlodipine maleate and its tablets, and levamlodipine maleate must be manufactured with levamlodipine as raw material. However, no evidence was provided to prove that Huasheng and Ouyi also produced the intermediate “a DMSO-d6 solvate of D-tartrate salt of (S)-(−)-amlodipine” when manufacturing levamlodipine maleate and its tablets. Therefore, the evidence submitted by Xitian Zhang is not sufficient to prove that the products manufactured by Huasheng and Ouyi are identical to the products directly obtained from the patented methods, and the burden of proof should not be borne by Huasheng and Ouyi to prove that the preparation of their products are different from the patented method.

According to Article 11 of Patent Law of PRC, the protection scope of method patent can only be extended to the products directly obtained from the patented method, that is, the original product obtained by using the patented method, and not to the subsequent products obtained by further processing of the original product. As previously stated, after performing the method in claim 1, “a DMSO-d6 solvate of D-tartrate salt of (S)-(−)-amlodipine”, or “a DMSO-d6 solvate of an L-tartrate salt of (R)-(+)-amlodipine” would be obtained directly. Levamlodipine maleate, Levamlodipine maleate tablets and levamlodipine manufactured by Huasheng and Ouyi are follow-up products obtained after further processing of the aforementioned products, not the products directly obtained from the patented method. Thus, the protection scope of the patent right involved cannot be extended to levamlodipine, levamlodipine maleate and its tablets. It does not matter whether the products can be used directly by consumers when identifying the "products directly obtained from the patented metho.

Based on such analysis, an intermediate product/ process patent for an imported product wherein said intermediate is substantially transformed to another product before importation such that said intermediate is no longer traceable in the final product, which is less likely to be deemed as patent infringement. This might be helpful for the international drug company to think about such rules. 

Mr. Michael Wu specializes in matters related to patent infringement, copyright infringement, trademark infringement, and unfair competition litigation, enforcement of intellectual property rights through administrative procedures and patent invalidation proceedings. Mr. Wu has earned licenses to practice as an attorney at law and as a patent attorney. Wu has a unique understanding of mobile telecommunications patent litigation, software patent litigation, and copyright litigation related to the internet. Wu obtained his Bachelors and Masters Degrees in Material Science from Wuhan Technology University in 1996 and 1999, respectively. He further pursued a J.M/J.D. degree at Peking University, School of Transnational Law in 2014, where he systematically studied Chinese and American law. Prior to practicing law, Wu spent ten years in the field of mobile telecommunications, and founded a company specializing in mobile telecommunication services. 

He has been invited to serve as a member of the China Global Advisory Council (GAC) of INTA for 2022 - 2023. He is also a frequent speaker of IP seminars and client training courses regarding China's IP strategy.