Beakers and Bunsens: Getting your timing right - Demonstrating plausibility and when to file a second medical use patent

22 January 2019

Deciding when to file a patent application can be a difficult decision. If you file a patent application too early there may not be enough information in the application as filed to convincingly show that the invention will work as proposed. However, waiting too long can mean that more prior art is citable against the patent application and it can be harder to show novelty and inventiveness. This balancing act is particularly difficult for second medical use type patents.

Second medical use claims are used before the European Patent Office (EPO) for inventions involving additional or improved treatments using already known drugs. For example, using a known drug to treat a different disease or changing the dosage regimen of a known drug to provide a better effect or to treat a different patient group. In the context of second medical use claims the EPO has made it clear that the therapeutic effect must be made plausible (in the sense of being very credible to a skilled reader) from the information in the patent document. This can play a part in assessing whether the new treatment claimed as the invention is sufficiently disclosed, and for assessing whether the problem of providing the treatment as claimed has been solved. The patent specification needs to contain enough information, and this usually means data from experiments from some stage during the drug development process, to make the therapeutic effect plausible.

Pharmaceutical developers are well aware that a new treatment is only definitively proved to be effective when the results of clinical trials are known. Many drugs fail during clinical trials. The EPO have also recognised that patentees must file their patent applications well before the clinical trials are completed and so will generally consider the therapeutic effect to be demonstrated as plausible without clinical trial results. However, the patent specification must have information in it, usually data from in vitro or animal models, to demonstrate the therapeutic effect claimed.

Therefore, if an announcement is made public that a clinical trial will be carried out (in future) before a patent application is filed, is that announcement to be viewed as a prior disclosure of something that can be expected to work and therefore deprive the claimed therapeutic treatment of novelty and inventiveness? These were issues considered in decision T239/16 (published in 2018).

The scrutinised document was information about a planned Phase II clinical trial aimed at prospective participants. The planned Phase II clinical trial involved a number of different dosage amounts and frequencies of the drug zoledronate for treating post-menopausal osteoporosis, as well as a placebo.

The EPO’s Board of Appeal (BoA) was able to conclude that information about the clinical trial in combination with general knowledge about the zolendronate meant there was no direct and unambiguous disclosure of an effective treatment being achieved and hence the claims were considered to be novel.

The BoA had to consider whether that information about the planned Phase II clinical trial made it obvious to try each of those dosage amounts and frequencies with a reasonable expectation of success and so rendering the claimed subject matter not inventive.

The BoA considered the fact that an active agent is being tested in a clinical study for the treatment of osteoporosis leads to an expectation of success, due to the fact that clinical studies are based on data obtained by pre-clinical testing, both in vitro and in animals, and require authority approval which takes ethical considerations into account. Therefore the skilled person would expect all study arms to treat osteoporosis effectively, unless he was dissuaded from this by the prior art. The BoA reviewed prior art documents and concluded that in the present case, the clinical trials were performed with more than a mere “hope to succeed” there was a reasonable expectation of success.

This conclusion sits uncomfortably with the current transparency rules for clinical trials requiring registration of a clinical trial and subsequent publication of the protocol long before any results of the trial are available.

It should be noted that Phase II clinical trials are scientific tests. The sponsor always hopes to get positive results, but the outcome cannot be known until after the clinical trials are performed and the data analysed. As noted above, drugs can fail at various stages during clinical trials. Furthermore, it is unlikely that every one of the study arms in a multi-arm clinical trial would be an effective treatment.

The patentees have subsequently asked the EPO’s Enlarged Board of Appeal (EBoA) to review T239/16 on grounds including that the BoA was incorrect to assume that due to the ethical considerations associated with clinical trials there is an expectation of success for all arms of an announced clinical trial. The EBoA have accepted the review and the outcome is expected in early 2019. We will analyse the outcome in due course.

The outcome could have an impact on deciding when, during the drug development process, to file patents relating to second medical use inventions. If the EBoA uphold the findings of the BoA in T239/16 there may be the need for careful coordination between patenting and clinical trial programmes within pharmaceutical companies. There may also be a need for additional early testing (leading to additional time and expense) for the sake of fulfilling the plausibility requirements for patenting.



Isobel Finnie

Isobel Finnie

Partner

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