China: Insight Into Recent PRB Decisions On Pharmaceutical /Biotech Inventions

The Patent Reexamination Board (hereinafter referred to as the PRB) is an organization under the SIPO (State Intellectual Property Office) of China. Its main functions are to examine appeals against a rejection decision made by the examining departments and to examine requests for invalidation of a granted patent. Although its decisions can be further appealed to Chinese court, the court is only empowered to decide on legality of the decisions. The final decision on the patentability of a patent application or on validity of a patent has to be made by the PRB itself. Especially, the invalidation proceedings very often parallel the civil proceedings on patent infringement as China adopts the so-called "dual track" system for patent validity and patent infringement. Such being the case, the PRB is recognized as a very important organ in the Chinese patent system and its decisions are intensively researched by both local and foreign patent practitioners. This article is a study of some of its recent decisions which concern pharmaceutical and biotech inventions.

Concerning the manner of claim amendment during invalidation procedure

In Chinese Patent No. 03139760.3 relating to new pharmaceutical compounds, the claimed compounds are presented as a general formula drafted in a typical Markush format. In the specification of the patent, there are two specific inventive compounds exemplified, namely Examples 2 and 4. However, they are not specifically claimed in the patent as granted. During the invalidation procedure of this patent, the patentee submitted an amendment of claims which narrowed down the claims to the compound of Example 2.

A question arose before the PRB whether the amendment should be accepted. According to the routine practice of the PRB and also as stipulated in the Guidelines for Patent Examination of the SIPO, a general formula compound claimed in Markush style and containing multiple variables is taken as an "integral" solution which cannot be split into specific compounds covered by the general formula (unless the variables are relatively few, say no more than four). Hence, an amendment taking one (or more) specific compound out of the general formula would usually be considered as going beyond the scope of the claims as granted.  In this case, however, peculiarities were found by the PRB. It was duly noted by the PRB that Example 2 was one of the only two specific compounds exemplified in the patent specification and moreover was the only compound on which biological test data were given. In view of this, the PRB concluded that Example 2 was in fact the "core" of the claimed invention, as could be appreciated by a person skilled in the art upon reading the patent specification as a whole. Eventually, the PRB accepted the amendment as an "exceptional" case and made a decision upholding the patent on the basis of the amendment.

To justify its decision, the PRB further commented that allowing the amendment other than not would better embody the legislative intent of the patent system encouraging inventive activities. Moreover, it would facilitate focusing on the substance of the invention in patent invalidation proceedings. 

This decision is generally welcomed by both the patent proprietors and professionals. On the issue of amendment of a patent during invalidation proceedings, there have been complaints about apparently over-rigid standards applied by the PRB, which seldom goes beyond the limited manners set forth in the Guidelines for Patent Examination. It has also been seen that some PRB decisions concerning this issue were considered by the court as overreaching the legal requirement for post-grant amendment. In its decision in this case, the PRB seems to be echoing the court's view as well as the complaints of the public. However, it still carefully emphasized the peculiarities of the case and apparently tried to make it an "exceptional" case but not a precedent.

Notwithstanding this decision, it is still advisable, when prosecuting a Chinese patent with a Markush general formula, to include specific compounds (especially those of commercial importance) as sub-claim(s) of the general formula claim. They could well serve as back-up claims in case the general formula claim is challenged.

Concerning ethic issue of inventions resulting from stem cell research

In China, just as in many other countries, inventions made out of stem cell (especially human embryo stem cell) research often encounter patentability problem and are always a subject of controversy. Since human embryo stem cells are necessarily prepared by obtaining and disrupting human embryo, which is considered as violating public morality, many of the inventions in this area cannot get patent protection.

In Chinese Patent No. 200680048227.7, the granted claims are directed to a nuclear reprogramming factor useful in inducing nuclear reprogramming of somatic cells and a process for preparing induced pluripotent stem cells by nuclear reprogramming of somatic cells. According to Example 12 of the description of the patent, iPS cells (induced pluripotent stem cells) were prepared from human skin fibroblast cells originated from a fetus. During an invalidation action against the patent, the dispute was focused on whether the patent violates public morality by exploiting human embryo for business purpose.   

After a study of the patent description, the PRB found that the human skin fibroblast cells used in preparing the iPS cells of the invention could be obtained either directly from the fetus or were commercially available and no manipulation on the fetus was involved in the invention according to the description. Specifically, the reference to fetus in Example 12 should be understood as referring to the original source of the human skin fibroblast cells so as to distinguish them from those of some other working examples which were originated from adult skin fibroblast cells. It should not be understood as an indication that they were obtained directly from the fetus. Moreover, one of the purposes of the invention is to avoid ethic issues of any manipulation on fetuses. With these findings, the PRB concluded that the patent as a whole had excluded any content of obtaining relevant cells directly from human embryos and that the opponent's assertion was invalid.

It seems that the PRB takes a rather technical approach in the analysis of the ethic issue involved in this case. They put emphasis on the inquiry of whether there is any direct manipulation of human embryos, which apparently indicates their understanding of the subtlety of the issue. Overreaching of the legal requirement for abide of public morality could be seen occasionally with the examining practice of the SIPO. However, the PRB's rationale expounded in this case is considered as a good example of correct application of the relevant legal provisions.

It is speculated that this decision represents a liberal position taken by the PRB towards stem cell research in response to the government's recent efforts to promote stem cell research, an area in which the government has been cautious. If this is true, it could be an encouragement for patent filers in this particular technical area.

Concerning inventive step assessment

In China, an invention on second medical use of a known drug can be patented with the so-called Swiss-type claim format. That is to say, the claim can be drafted as "use of compound X in manufacture of a medicament for treating disease Y", with disease Y being a new indication. However, an inventive step issue may arise when the new indication intended in the invention is seemingly close to the existing indication of the drug that is known from the prior art. The PRB's recent decision on a request for reexamination of Patent Application No. 200880011264.X represents its thinking on inventive step of inventions of this kind.

The claimed invention in this case is a new indication, which is estrogen receptor negative breast cancer, of ActRIIa-Fc fusion protein (an activin-binding polypeptide) with identified peptide sequence. The application was initially rejected by the examining department and was brought to the PRB for its review. As prior art, the main reference relied upon by the examining department was D3, which discloses use of ActRIIa peptides for the treatment of cancers including activin dependent cancers such as ovarian cancer. Another reference, D2, discloses use of an activin antagonist in the treatment of androgen independent tumor such as breast cancer as well as a solution of screening for types of carcinoma suitable for treatment with the activin antagonist. It was concluded by the examining department that, based on D3 in view of D2, it would have been obvious for a person skilled in the art to arrive at the claimed invention, as D2 provides an incentive to use an activin-binding protein to alleviate or inhibit the growth or survival of breast cancer cells.

It was found by the PRB that the indication intended by the claimed invention, which is estrogen receptor negative breast cancer, was not mentioned in D2. In other words, it does not disclose use of activin antagonist in the treatment of estrogen receptor negative breast cancer. Moreover, it also does not disclose ActRIIa-Fc fusion protein as an activin antagonist. It was specifically noted by the PRB that D2 only disclosed inhibition of growth of androgen independent breast cancer cell line SC-4 in the presence of an activin antagonist. However, androgens and estrogens have different receptors and different effects on various types of cancer cells, as is well known in the art. Therefore, D2 would have not made it obvious for a person skilled in the art to think of the effect of activin on estrogen independent cancer cells, let alone the use of ActRIIa-Fc fusion protein in the treatment of estrogen receptor negative breast cancer, which is the claimed invention. The rejection was overturned based on the above analysis.

As is typical in the Chinese patent practice, the PRB followed the problem-solution approach (as in the European Patent Office) in the assessment of inventive step in this case. It can be seen that its decision was largely based on careful analysis of the technical facts identified in the prior art references. Particularly in this case, androgen independent breast cancer, which was mentioned in D2, was noted as distinctive over estrogen receptor negative breast cancer. In fact, there was no evidence in the prior art showing that use of activin could achieve the same effect on estrogen independent cancer cells.

Interestingly, the PRB referred to additional references submitted by the applicant as proof of the knowledge in the prior art, apart from the analysis of the content of prior art references relied upon by the examining department. These additional references teach that activin has no effect on estrogen receptor negative breast cancer cell lines, meaning that estrogen receptor negative breast cancer is not an activin dependent cancer. Apparently, these teachings contribute to the finding that there would have been no motivation to use ActRIIa-Fc fusion protein in the treatment of estrogen receptor negative breast cancer.

Mr. Jiancheng Jiang is managing partner at Peksung Intellectual Property. He can be contacted at:  

This article first appeared in Asia IP, October, 2015, published by Apex Asia Media Ltd.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on

Click to Login as an existing user or Register so you can print this article.

Some comments from our readers…
“The articles are extremely timely and highly applicable”
“I often find critical information not available elsewhere”
“As in-house counsel, Mondaq’s service is of great value”

Mondaq Advice Centre (MACs)
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at and we will use commercially reasonable efforts to determine and correct the problem promptly.