Whether to file a Chapter 2 Demand

The Patent Cooperation Treaty (PCT) application procedure contains an optional examination phase. The applicant may choose to file a so-called Chapter 2 Demand (usually written using Roman numerals as a Chapter II Demand). The effect of filing a Chapter 2 Demand is that an additional examination step takes place during the international phase of the PCT. In this article, we discuss in more depth what is a Chapter 2 Demand and how to decide whether to file one.

Preceding Stages

Prior to making a decision whether to file a Chapter 2 Demand, the applicant should have received the International Search Report, drawn up by the International Searching Authority, which comes with a Written Opinion of the International Searching Authority (WO/ISA) on the patentability of the invention set out in the claims. The Written Opinion is best thought of as a preliminary view on patentability; its conclusions are frequently challenged later in the application procedure. You should have an opportunity to review the International Search Report and Written Opinion prior to making a decision about the Chapter 2 Demand.


The deadline to file a Chapter 2 Demand is usually 22 months from the earliest priority date of a PCT application, although it is extended until 3 months from the date of the International Search Report, if that is later.

Contents of Chapter 2 Demand

A Chapter 2 Demand includes an application form and an official fee must be paid. A Chapter 2 Demand is filed with one or both of (a) claim amendments and (b) arguments in favour of the patentability of the invention. There would be no purpose in filing one without arguments or amendments ("Article 34 amendments"). Therefore, the Chapter 2 Demand is usually the first opportunity to submit patentability arguments in writing (although see also the less frequently used PCT Direct procedure). Due to the requirement to pay a fairly substantial official fee and the associated work of analysing the International Search Report and preparing amendments and/or arguments, this step is quite expensive (several thousand pounds at least).

Effect of Chapter 2 Demand

If no Chapter 2 Demand is filed, then a patentability report, known as the International Preliminary Report on Patentability (IPRP) is drawn up based on the preliminary findings of the International Search Authority. Usually, it is simply a repeat of the search stage Written Opinion (WO/ISA).

If on the other hand a Chapter 2 Demand is filed, then an international examiner will review the case, reviewing patentability arguments included with the Chapter 2 Demand and, if the claims are amended, considering the revised claims. They will then issue a Written Opinion of the International Preliminary Examination Authority (WO/IPEA), which will hopefully differ from the search stage Written Opinion (WO/ISA). If there is time, then it may be possible to make one or more additional submissions to the international examiner and potentially receive one or more further Written Opinions (WO/IPEA). In due course, the examination procedure stops and the final Written Opinion is used to prepare the IPRP.

Thus, in short, filing a Chapter 2 Demand introduces an additional review stage into the international phase of the PCT application procedure before the applicant is required to make a final choice of the territories where they will enter the national phase of the PCT. However, is this optional step worth the cost? We will now set out the main factors to consider.

Advantages and Disadvantages

Generally, an applicant files a Chapter 2 Demand with the aim of receiving a positive IPRP in order to speed up or reduce the cost of the subsequent national phase application procedure. If (as is the case for most of our clients) the European Patent Office is the International Search Authority and if the IPRP is positive, the European Patent Office will usually simply grant a corresponding patent, saving time and money.

However, other Patent Offices will typically carry out further examination and we frequently see cases where the European Patent Office, as the International Search Authority, gives a positive IPRP and go on to issue a European Patent, but some of the US, Japanese, Chinese and Korean Patent Offices (for example) make additional objections. The US Patent Office is particularly prone to raising objections on the basis of prior art documents not considered during Chapter 2. Accordingly, obtaining a positive IPRP does not mean that examination will necessarily be straightforward and so even where a positive IPRP is obtained this does not always save costs.

Armed with a positive IPRP an applicant can consider requesting acceleration of their application in the national phase using a Patent Prosecution Highway scheme, based on the PCT work product. Nevertheless, there is usually a cost for attorney time to request this and, as described above, there is no guarantee that national Patent Offices will agree with the conclusion of the IPRP.

A Chapter 2 Demand can be particularly helpful if there is a single, clear way forward with an apparent high chance of leading to allowable patent applications. However, it is often the case that there is not such a clear path. There may be several possible ways to consider amending an application. It is sometimes the case that amendments might be considered for the United States which differ from those in other territories (e.g. Europe and China) which have less lenient rules on amendment options. In this case, a Chapter 2 Demand may not save costs and it may be better to wait to the national phase and make different arguments in different territories.

Related to this, the European Patent Office (for example), usually requires applicants to maintain at most one independent apparatus claim and one independent method claim. However, the US Patent Office does not have this restriction. Therefore we often see situations where the amendments we would make in the United States and in Europe are different. In this case, the single central amendment process in Chapter 2 of the PCT is not advantageous.

Furthermore, some subject matter is only patentable in some jurisdictions. If the international examination authority does not grant patents for the subject matter there is little motivation to file a Chapter 2 Demand and receive a further negative opinion. An example would be when a Europe-based applicant has a PCT application with claims for a method of treatment that were potentially patentable in the United States but not patentable before the European Patent Office. The European Patent Office as the International Examination Authority will continue to raise objections and arguments may be better made directly to the US Patent Office in the national phase.

Although a Chapter 2 Demand is fairly expensive to file, some of that cost is for the analysis of the ISR/WO which is work that will anyway be carried out in the national phase. Furthermore, where the European Patent Office is the International Examination Authority, where a Chapter 2 Demand has been filed, the cost of entering the European regional phase is reduced. Therefore, some of the cost is simply brought forward in time rather than additional expense and later cost savings can be substantial if examination in the national phase is simplified as a result.

On balance, it remains more common to not file a Chapter 2 Demand. However, where there is a single clear way forward, or some commercial pressure to demonstrate patentability, the Chapter 2 Demand process should be strongly considered.

If you have any questions about this article, please contact us.

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