Under Norwegian patent law, trials necessary for the completion of an invention have been exempted from inclusion in the prior art even if they were performed in a manner that did not enable the inventor to restrict access to a limited and well-defined group of people. Consequently, inventions that could have been – and maybe even were – observed by third parties during a trial prior to the filing of a patent application have been patented in Norway.

This exemption is not stated explicitly in the Patents Act, but it is clearly stated in the preparatory works. The reasoning is that some inventions cannot be completed without experimentation and trials under conditions where it is not possible to prevent outsiders from obtaining some information about the invention. The preparatory works make it clear that the inventor should take reasonable measures to prevent or limit the public's access to the invention and require the trials not to take place to a larger extent or for a longer period than required by the character of the invention.

The most commonly cited example from case law in which this exemption came into play is Statfjord A, in which the Norwegian Patent Office Board of Appeal concluded that an invention relating to oil field production platforms had not been used in public beyond what was necessary for reasonable trial and experimentation.

However, while similar exemptions exist in Sweden and Denmark, none exist under the European Patent Convention (EPC). Since Norwegian patent law is harmonised with the EPC, particularly with respect to patentability requirements, this exemption may no longer exist. This question was recently addressed by a Norwegian court.

Celltrion v Biogen Inc

On 7 February 2018 the Oslo District Court reached a decision on the validity of Norwegian Patent NO 332893 that may be the beginning of the end for the Nordic trial exemption. The patent, originally applied for by IDEC Pharmaceuticals, is owned by Biogen Inc and is a second indication patent on use of a particular anti-CD20 antibody known as Rituximab for treating B-cell lymphoma.

The plaintiff, Celltrion, developed a biosimilar rituximab for which Sandoz holds the marketing rights in Europe. Celltrion sued Biogen in December 2016 and submitted five different grounds for its claim that NO 332893 should be found invalid. Sandoz GmbH and its Danish subsidiary company Sandoz A/S joined the suit in June 2017. The first argument was that the invention lacked novelty on the day on which the application had been filed. The city court did not address the remaining arguments since they found in favour of the plaintiff based on the first argument.

The use of Rituximab in itself had not been novel when the patent application was filed. It had been tested for several treatments going back as far as the early 1990s and was approved by the Food and Drug Administration in 1997 and the European Medicines Agency in 1998. NO 332893 claimed priority from a US patent application filed in August 1998, but the parties agreed that the international filing date of 11 August 1999 was the relevant date for determination of the question of novelty.

ECOG study

The prior art forming the basis for the lack of novelty argument was an Eastern Cooperative Oncology Group (ECOG) clinical study (ECOG 1496) commenced in 1998, which involved 311 patients in addition to doctors and other personnel. According to the plaintiffs, all features of the patented invention were disclosed by the protocol for the study and the patient consent form. These documents were, according to the plaintiffs, publicly available as they had been shared with doctors and patients that had taken part in the study, as well as patients that could have taken part.

Biogen did not dispute the actual teaching of the invention by the documents from ECOG 1496. However, it argued that those documents had not been publicly available on the day on which the application was filed and were therefore not part of the prior art.

Trial exemption

Consequently, the question before the court was not whether a particular prior art reference actually did teach the invention, but whether the ECOG 1496 clinical trials represented prior art that had been available to the public. The plaintiffs argued that the trial exemption had been part of Norwegian patent law up until Norwegian patent law was harmonised with the EPC. The defendant agreed that no explicit trial exemptions exist under the EPC and it was therefore unsurprising that the court concluded as it did: there are no longer any trial exemptions in Norwegian patent law and the Norwegian courts must interpret the Norwegian patent law's patentability requirements in a manner that does not conflict with corresponding requirements according to the EPC.

Clinical studies as prior art

The court then went on to the more traditional problem of deciding when information becomes available to the public "by use or in any other way".

According to Celltrion and Sandoz, ECOG 1496 had made the invention available to the public prior to the relevant priority date. As a result of the study, the invention had become known to a number of persons who did not have a particular relationship with the applicant. Since the study was not initiated, organised, designed or financed by the applicant, the participants in the study could not be considered as consisting only of people who had a particular relationship with the applicant and were not part of the general public.

Biogen disagreed. It argued that ECOG 1496 was a necessary trial of the invention and that the applicant had taken part in the trial. Further, it argued that the lack of relevant case law made it necessary to consider other factors, such as the purpose and effect of the law in view of such facts as the advantages for society as a whole that clinical trials are performed and that the development of pharmaceuticals is economically risky and requires a lot of capital.

While maintaining that participating medical personnel and others with professional involvement in the clinical trials may be bound to secrecy, it is impossible and even unethical to try to prevent patients from talking about their own medical condition. Biogen nevertheless argued that all recipients of information relating to the invention had a particular relationship with the applicant and could not be considered part of the public.

The court found in favour of the plaintiff and found the patent to be invalid for lack of novelty over ECOG 1496, which had been available to the public prior to the date of application for patent. The court did not find it reasonable to consider all of the doctors and patients that had received information about the invention as having a particular relationship with the applicant. Rather, their relation to the applicant had to be considered as members of the public.


The decision has been appealed, so how the appellate court views the case remains to be seen. However, it is unlikely that the trial exemption will be resurrected, as this would create a lack of harmonisation with the EPC. The trial exemption therefore seems to be a thing of the past.

Slightly less unlikely is the possibility that the appellate court will find that participants in clinical trials are not members of the public. However, in reality, this would be a way of sneaking the trial exemption back in through the back door. The arguments submitted by Biogen may be presented in many cases other than clinical trials of pharmaceuticals. Many inventions are advantageous to the public and require large investments of capital, and many such inventions are precisely the type of invention that the earlier trial exemption was intended to cover. Examples may include inventions that require trials at airports or at sea. The court has relied on a number of legal sources, including European Patent Office case law. The evaluation of these sources in the decision is thorough and arguably correct. There are no statutes or case law that can reasonably be interpreted to exempt participants in clinical trials from the public and instead consider them as having a particular relationship with an applicant in the absence of any reasonable efforts by the applicant to create such a relationship. The appellate court is expected to decide accordingly.

For further information on this topic please contact Tom Ekeberg at Zacco by telephone (+47 22 91 04 00) or email ( The Zacco website can be accessed at

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