How to make the most of the Patent Prosecution Highway

The Patent Prosecution Highway (PPH), which first started operating over fifteen years ago, is a set of cooperative agreements between patent offices that allows applicants to formally submit a positive opinion from one patent office to another patent office in the form of an accelerated examination PPH request. It was first devised by the Japanese Patent Office as a way of alleviating the workload of their Examiners. Now over 55 patent offices, including the European Patent Office (EPO), the US Patent and Trade Mark Office (USPTO) and the China National Intellectual Property Administration (CNIPA) are part of the program.

In principle, a PPH agreement between two patent offices should be an agreement that, at least on the whole, the quality of search and examination carried out by the Examiners of the two offices and the standards of assessing patentability applied to each application are aligned, meaning that the office receiving the PPH request would merely give the application and prior art cited previously a cursory review, check any local patent requirements, and then allow the case. In other words, the fact that a PPH agreement is in place between two patent offices implies an element of trust between the two offices. However, in practice the extent of this trust varies greatly, mainly based on the office the Applicant is submitting the PPH request to.

As a result of this variance, there is a polarized view amongst some representatives regarding how useful PPH can be, with some representatives never recommending it and some representatives always recommending it. I think that it’s actually best to carefully consider whether PPH is the right strategy for each application in turn and then request PPH not necessarily in all of the countries where an agreement is in place, but instead only at offices where there is an established level of trust. It is also helpful, where you know that PPH would be particularly beneficial from an early stage (such as when working with a client that has a tight budget) to file the priority and International applications (assuming a typical filing strategy) in such a manner that it increases the likelihood of obtaining a useful positive opinion and of the PPH requests succeeding (i.e. leading to straightforward grant of the application). In this regard, PPH can be beneficial in scenarios where the client has a firm idea of invention, the scope they want, the invention can be described straightforwardly using non-complicated nomenclature and the client has a good grasp of the most relevant prior art. As a result, from experience PPH tend to work well for clients that are highly familiar with the patent system and most likely have an established portfolio already. 

Finally, it is important to file a PPH request only when the situation is right, as a PPH request that does not lead to straightforward grant can have detrimental consequences. For example, it is important to note that a PPH request is also a request for accelerated examination, and so, if the request does not lead to straightforward grant, office actions are going to issue sooner and more frequently than without the request in place, and this may mean that the client incurs significant patent prosecution costs close together rather than spread out.  


Ideally, if an applicant wishes to make significant cost savings at the regional/national phases of patent prosecution, more work and costs need to be committed to the patent drafting and the earlier stages of prosecution. In particular, PPH works best when only prior art objections (if any) are raised against the application, as with such objections there is a good level of harmony across patent offices. Bearing this in mind, the applications that are most likely to benefit from the PPH route are those that are clear and supported with good data. Poor and prophetic data in an application (especially for biotechnology and chemistry-related inventions) can be viewed very differently across patent offices, and so even if you do obtain a positive opinion that allows you to submit PPH requests, there would be a high level of uncertainty of whether those PPH requests will lead to straightforward grant. 

There are of course also considerations regarding how broad to make the claims. Often the broadest claim language is not the clearest and/or poses sufficiency/ support/written description etc. issues depending on the data available, so decisions may need to be made regarding whether narrowing the claims in order to save prosecution costs is the right strategy.

Once the application is filed, we recommend those wanting to use PPH to obtain search and examination during the priority year. Whilst the applicant may not want to keep the priority application pending (for example if a long patent term is important in the country with the priority filing), having an early search can be useful for determining whether further data is necessary, or whether claim limitations need to be made when filing the International application.

If, during the International phase of prosecution, the International Search Authority (ISA) issues a positive opinion then great, nothing more needs to be done at this stage. If a negative opinion issues, then the nature of the objections affects whether or not PPH is still appropriate. As discussed above, if only prior art objections are raised, and there is a straightforward way of dealing with them, we generally recommend filing a Demand for International Preliminary Examination here with the aim of persuading the Examiner of issuing a positive opinion before the end of the International phase. If the Examiner raises straightforward clarity objections (especially if they can be dealt with with claim amendments that are acceptable to the client) then again, there may be merit in filing a Demand.

If the Examiner raises objections under sufficiency, i.e., that the data does not support the breadth of the claim, then PPH may not be the best strategy. Even if it is possible to persuade the Examiner that the claims are sufficient and a positive opinion is issued, each PPH request based on the positive opinion at the International phase, will result in the local Examiner receiving the request seeing that sufficiency objections were raised. The Examiners will likely form their own view of sufficiency. As the standards of sufficiency vary so much from office to office and even examiner to examiner, the chance of each PPH request leading to straightforward grant is somewhat reduced.

During national/regional phase, PPH requests must be filed before substantive examination commences. When working out when and where to make the PPH requests, it is worth bearing in mind that not all countries/regions have PPH agreements in place with all ISAs. It may be worth filing the PPH request as soon as possible in a national phase that does have an agreement with the ISA, and then using a resulting positive opinion from that national office as the basis for a PPH request in other jurisdictions. 

For example, there is currently no PPH agreement in place between Brazil and the EPO when the EPO is the ISA. In order to use PPH in Brazil, we could either accelerate proceedings at the EPO (because there is a PPH agreement in place between Brazil and the EPO regional phase) or file the PPH request early at an office that does have an agreement with Brazil, such the Japanese Patent Office in the hope that a positive opinion will issue before the deadline for requesting examination in Brazil. 


A table showing which offices have agreements can be found at the PPH Portal website.

Where to file PPH requests

As discussed above, the likelihood of straightforward grant following a PPH request depends, at least in part, on the trust that the office where the request is made has in the office where the positive opinion originates from. An indication of the trust of the office receiving the PPH request is presented in the statistics on the PPH Portal website, which shows the percentages of grant and first action allowance with PPH requested applications compared to all applications. Unfortunately, the data are available for only some of the countries that are part of the PPH program, but it is still worth looking at this when considering whether or not to use PPH.

From experience, Kapil has had the most positive PPH results when filing at the requests at the Japanese Patent Office, the Korean Intellectual Property Office, the Canadian Intellectual Property Office and IP Australia (and the statistics support this). According to the statistics, PPH requests are also beneficial in Mexico, Chile, Brazil, Singapore, Taiwan and Saudi Arabia. 

The statistics are not available for the USPTO. In Kapil’s experience, the USPTO will generally carry out their own prior art searches even when a PPH request has been submitted, but may be lenient on non-prior art objections (such as written description and enablement) when a PPH request is filed. So, if the International Search Authority raises no difficult non-prior art issues, and the applicant feels confident that no more relevant prior art is available than what has been cited during the International phase, a PPH request at the USPTO may be recommended.

The statistics are also not available for the EPO. Our experience is similar to that at the USPTO; the EPO will carry out their own search regardless of whether or not a PPH request has been submitted, but if the Examiner can satisfy themselves that the claims are novel and inventive, they will tend to be less fussy regarding clarity or sufficiency. However, the EPO is strict on added matter, and so if claim amendments made during the International phase have less than perfect basis in the application as filed, an objection from the EPO should be expected. 

Our comments are based PPH requests following positive opinions from the EPO, the USPTO or IP Australia. PPH requests based on EPO tends to be particularly successful.


  • Considerable cost savings in foreign agent service charges and translation services.
  • Fast grant.
  • No official fees associated with filing the requests, and foreign agent services charges for filing the request tend to be low.
  • International Search Authorities/International Preliminary Examination Authorities understand the advantages of PPH and tend to work with you to get a positive opinion filed before the end of the International phase.
  • Concessions in claim scope often have to be made in order for PPH to be available.
  • There are front-loaded costs in drafting, requesting search and examination of the priority application (optional) and possibly filing a Demand during the International phase.
  • The data presented in the application generally needs to be good for PPH to work.
  • PPH agreements can be with some offices and not others, meaning that sometimes strategic early PPH requests have to be filed. 
  • The positive opinion submitted in a PPH request can be simply ignored by an Examiner, which is frustrating.

Prosecuting the cases in multiple jurisdictions and addressing the same objections repeatedly is clearly an inefficient process. The PPH program provided hope that patent offices could simply take positive opinions from other offices and grant the patents, saving both the offices and the Applicant time and costs. Unfortunately, we aren’t quite there yet; however, it is a step in the right direction and should be considered for some cases. 

This article is for guidance only and should not be taken as legal advice. For more information on the PPH program, or any other IP advice, contact Kapil Agashi or another member of the team at Greaves Brewster.