On March 20, the Beijing High People’s Court found for Lifang client Shenyang Shuangding Pharmaceutical Co., Ltd. (“Shuangding”) in the final judgement (2009 Gao Xing Zhong Zi No. 124) in the patent invalidation administrative case involving Patent No.01114136.0, “Kudiezi Injection and its Preparation Process” (“the involved patent”).

On December 29, 2006, Shuangding filed an invalidation application with the Trademark Review and Adjudication Board (TRAB). TRAB issued Decision No.10530 on September 26, 2007, determining that Claims 1 to 4 of the involved patent were invalid but sustained the patent based on Claims 5 to 8.

Shuangding filed an appeal with Beijing No.1 Intermediate People’s Court, which issued the first instance ruling (2008 Yi Zhong Xing Chu Zi No.211), ordering TRAB to withdraw the part in Decision No.10530 sustaining the involved patent based on Claims 5 to 8, and to re-examine the invalidation application regarding said claims.

TRAB and Hua Yuqiang, the patentee, appealed to the Beijing High People’s Court, which rejected the appeal and sustained the first instance ruling.

Lawyer's Note:

Claims 5 to 8 of the involved patent protected a process for preparing Kudiezi injection, comprising the steps: filtration with hollow fibre having a molecular weight cut-off of 50,000; followed by filtration with hollow fibre having a molecular weight cutoff of 10,000; and collecting the filtrate after each step.

One reference document disclosed a process for preparing Shenjincao (Lycopodium calvatum) injection, comprising the steps: filtration with membrane having a high molecular weight cut-off; filtration of the resulting filtrate with membrane having a low molecular weight cut-off; discarding the filtrate but collecting the substances that do not permeate the membrane. The membranes used have molecular weight cut-offs lower than 50,000.

TRAB believed that in the reference document, the two ultrafiltration processes were carried out to remove and discard substances having a molecular weight higher than the first cut-off value and lower than the second cut-off value, which was different from the function of the two filtrations in the involved patent that removed and discard substances having higher molecular weight and retained the effective substances having low molecular weight. TRAB further held that the reference document did not furnish the technical motivation to apply double filtration to the present invention. Therefore, TRAB determined that the involved patent possessed inventiveness compared with the reference document.

Both the first and second instance courts held, however, that the reference document and the involved patent were both related to filtration and purification of herbal medicine extracts. The court reasoned that a person skilled in the art was aware that the effective ingredient of Kudiezi extract had low molecular weight, and that one could have, based on the double filtration process disclosed in the reference document, found the appropriate membranes for removing substances having higher molecular weight, in a process essentially identical to that of the reference document. The court believed that a person skilled in the art could have acquired the filtration process of the involved patent by making simple adjustments to the process disclosed in the reference document because it was characteristic of the filtration process that purification could be achieved without absorbing the effective ingredient. Therefore, the court found TRAB’s decision that the reference document did not provide technical revelation because its process was different from that of the involved patent unconvincing and did not support it.

Under the Guidelines for Examination, the following steps are usually followed to determine whether a claimed invention possess the inventive step:

(1) Determining the closest prior art;

(2) Determining the distinguishing features of the invention and the technical problem actually solved by the invention;

(3) Determining whether or not the claimed invention is obvious to a person skilled in the art.

However, the above three part test should not be followed rigidly in deciding whether some inventions possess the inventive step. For example, for a large number of inventions by combination, selection or diversion, more emphasis should be given to their unexpected technical effect than to the simple application of the above test.

In the case at hand, TRAB failed to do so and made an erroneous conclusion. As it turned out, the involved patent was a selection invention compared with prior art.

The reference document disclosed a twostep filtration process as well as the choice of two membranes having molecular weight cut-offs lower than 50,000. The involved patent simply made more particular selections within the above range of options, i.e. selecting filters having molecular weight cut-off higher than 50,000 and lower than 10,000. This fell inside the definition of a selection invention provided in Section 4.3, Chapter 4, Part II of the Guidelines for Examination. As to the selection of filtrate or substances that did not permeate, it was a choice by one skilled in the art based entirely on product requirement and did not involve any inventive step. Subject to Section 4.3, Chapter 4, Part II of the Guidelines for Examination, “in determining the inventive step of a selection invention, the main factor to be considered is whether the selection can bring about unexpected technical effect.” The involved patent did not produce any unexpected technical effect and therefore did not involve an inventive step.

By Liu Yongquan, Partner, Lifang &Partners