The Boards of Appeal at the European Patent Office assess the requirement of an inventive step under the so-called “problem and solution” approach. One of the first Board of Appeal decisions to develop the problem and solution approach was T24/81, which was published back in October 1982.
The problem and solution approach essentially includes three stages. They are:
- Identify the closest piece of prior art;
- Identify the objective technical problem by comparing the claim under examination to the closest piece of prior art; and
- Determine whether the skilled person, on looking to solve the objective technical problem, would be incited by the teaching of the prior art to arrive at the claimed subject matter.
Additionally, when the claimed invention relates to genetic engineering and biotechnology, the third stage is modified to refer to the requirement of a reasonable expectation of success. Specifically, the third stage is revised to read as follows:
3) Determine whether the skilled person, on looking to solve the objective technical problem, would be incited by the teaching of the prior art to arrive at the claimed subject matter with a reasonable expectation of success.
The problem and solution approach at the UPC
There has been much interest as to whether the judges at the Unified Patent Court (UPC) would adopt the problem and solution approach on considering the requirement of an inventive step. One could argue that it would make sense to adopt the problem-and-solution approach for legal certainty. By doing so, the granting authority, i.e. the EPO and the Courts, would be applying the same inventive step test. This would also be in line with the preamble to the Agreement on the Unified Patent Court (UPCA), specifically the portion of the preamble of the UPCA which reads:
“Wishing to improve the enforcement of patents and the defence against unfounded claims and patents which should be revoked and to enhance legal certainty by setting up a Unified Patent Court for litigation relating to the infringement and validity of patents”. [emphasis added]
On 25 November 2025, the Court of Appeal of the UPC handed down the much-awaited decision concerning the dispute between Amgen Inc. and Sanofi and Regeneron Pharmaceuticals Inc.
The patent in issue was Amgen’s European patent number 3666797, which had claims directed towards the therapeutic use of a monoclonal antibody or an antigen-binding fragment thereof to treat or prevent hypercholesterolemia or an atherosclerotic disease related to elevated serum cholesterol levels or for reducing the risk of a recurrent cardiovascular event related to elevated serum cholesterol levels.
The issue of inventive step
As inventive step was an issue to be decided, this is the first UPC Court of Appeal decision to comment on the legal test to be applied in assessing whether the subject matter of a claim is inventive.
On looking at inventive step at a general level, the UPC Court of Appeal held at section 124 of their Decision that:
“124. National courts of the various EPC countries have different approaches and use different guidelines when assessing whether an invention involves an inventive step. One of those approaches is the so-called ’problem-solution-approach’ used by the European Patent Office (EPO) and the Technical Boards of Appeal (TBA) of the EPO. In some jurisdictions, such as France, Italy, The Netherlands and Sweden, this approach is applied as well, but not necessarily as the only possible approach. In other jurisdictions, such as Germany and the UK, other approaches – sometimes referred to as more ’holistic’ – are used. Despite the differences in approach, all of these are just guidelines to assist in the establishment of inventive step as required by Art. 56 EPC, that, when properly applied, should and generally do lead to the same conclusion.” [emphasis added]
Against that backdrop, the UPC Court of Appeal then went on to describe how they would be assessing inventive step, which is different to the problem and solution approach.
According to the UPC Court of Appeal, the first step is to determine what the object of the invention is, i.e., the objective problem. This involves looking at the disclosure of the patent. Specifically, at section 127 of the Decision, the UPC Court of Appeal held:
„127. It first has to be established what the object of the invention is, i.e. the objective problem. This must be assessed from the perspective of the skilled person (m/f – hereinafter referred to as ’it’), with its common general knowledge, as at the application or priority date (also referred to as the relevant date) of the patent. This must be done by establishing what the invention adds to the state of the art, not by looking at the individual features of the claim, but by comparing the claim as a whole in context of the description and the drawings, thus also considering the inventive concept underlying the invention (the technical teaching), which must be based on the technical effect(s) that the skilled person on the basis of the application understands is (are) achieved with the claimed invention.“ [emphasis added]
This is interesting on at least three fronts.
As far as the EPO is concerned, by starting from the closest prior art, you identify the objective technical problem. The technical problem is objective because it is based on the closest prior art and not on what the patentee presents in the patent as the technical problem they set out to solve. According to the EPO, the technical problem set forth in the patent was the subjective technical problem. Subjective in the sense that it may have overlooked more pertinent, closer prior art.
Secondly, on identifying the objective technical problem by way of the problem and solution approach, it is all about comparing the claim to the closest prior art and identifying any difference(s). This does result in focussing on individual features of the claim when identifying the objective technical problem. As confirmed by the UPC Court of Appeal, on identifying the objective technical problem, you must look at the claim as a whole and not focus on its individual features.
Thirdly, it is interesting how the UPC Court of Appeal have kept the term “objective problem” in their test, but tied the word “objective” to the “object of the invention“.
Once the objective problem has been identified, the next question is to identify the closest piece of prior art. The UPC Court of Appeal use a different term. Rather than the term “closest piece of prior art”, they use the term “realistic starting point”. Specifically, at section 131 of the Decision, we are taught that:
“131. A starting point is realistic if the teaching thereof would have been of interest to a skilled person who, at the relevant date, wishes to solve the objective problem. This may for instance be the case if the relevant piece of prior art already discloses several features similar to those relevant to the invention as claimed and/or addresses the same or a similar underlying problem as that of the claimed invention. There can be more than one realistic starting point and the claimed invention must be inventive starting from each of them.” [emphasis added]
I would say that it is clear that a realistic starting point is very similar or almost identical to what the Boards of Appeal would identify as the closest piece of prior art. Specifically, the Boards of Appeal have repeatedly pointed out that the closest piece of prior art for assessing inventive step is normally a prior art document disclosing subject matter conceived for the same purpose or aiming at same objective claimed invention having the most relevant technical features in common i.e., requiring the minimum of structural modifications (see EPO’s Case Law Book (11th Edition), Chapter I, D,3.1). Realistic in the sense that it is the most promising springboard towards the invention.
The UPC Court of Appeal have also stated that there may be more than one realistic starting point. I would say that this is not controversial in the sense that, under the problem and solution approach, there might be more than one piece of closest prior art advanced by an opponent in opposition proceedings. This is confirmed in the context of opposition proceedings. Specifically, the Examination Guidelines before the EPO at G-VII, 5.1 state that:
“However, applying the problem-solution approach from different starting points, e.g. from different prior-art documents, is only required if it has been convincingly shown that these documents are equally valid springboards. In particular in opposition proceedings, the structure of the problem-solution approach is not that of a forum where the opponent can freely develop as many inventive-step attacks as desired in the hope that one of them has a chance of succeeding (T 320/15, Reasons 1.1.2).”
As far as the attributes of the skilled person are concerned, there is nothing controversial in the UPC Court of Appeal’s finding. Specifically, at section 132 of their Decision, the UPC Court of Appeal held:
„132. The skilled person has no inventive skills and no imagination and requires a pointer or motivation that, starting from a realistic starting point, directs it to implement a next step in the direction of the claimed invention. As a general rule, a claimed solution must be considered not inventive / obvious when the skilled person would take the next step prompted by the pointer or as a matter of routine, and arrive at the claimed invention.„
When you consider the above section, it is clear that, as a general rule, a claimed solution would be considered as lacking an inventive step if the skilled person is pointed or prompted in the direction of the claimed invention by the prior art.
A reasonable expectation of success
As the subject matter of the claims was biotechnological, there was also a discussion about the requirement of a reasonable expectation of success. The UPC Court of Appeal held that:
„135. A reasonable expectation of success implies the ability of the skilled person to predict rationally, on the basis of scientific appraisal of the known facts before a research project was started, the successful conclusion of that project within acceptable time limits.„
„136. Whether there is a reasonable expectation of success depends on the circumstances of the case. The more unexplored a technical field of research, the more difficult it was to make predictions about its successful conclusion and the lower the expectation of success. Envisaged practical or technical difficulties as well as costs involved in testing whether the desired result will be obtained when taking a next step may also withhold the skilled person from taking that step. On the other hand, the stronger a pointer towards the claimed solution, the lower the threshold for a reasonable expectation of success.„
Once again, this is not a departure from the established case law of the EPO’s Board of Appeal. In fact, it is clear that the UPC Court of Appeal lifted the maxim handed down by T694/92, which was published in May 1996.
As far as burden of proof is concerned, the UPC Court of Appeal confirmed that the burden of proof rests with the person objecting to the presence of an inventive step. This can be gleaned from section 134 of the Decision, which reads:
„134. The burden of proof that the results were clearly predictable or the skilled person would have reasonably expected success, i.e. that the solution he envisages by taking the next step would solve the objective problem, lies on the party asserting invalidity of the patent.„
Staying with the burden of proof and the concept of a reasonable expectation of success, it is also clear that if the patentee is able to substantiate that there is no reasonable expectation of success, then the burden of proof rests with the party bringing the revocation action. This is clear from section 137 of the Decision, which reads:
„137. When the patentee brings forward and sufficiently substantiates uncertainties and / or practical or technical difficulties, the burden of proof that these would not prevent a skilled person from having a reasonable expectation of success, falls on the party alleging obviousness.„
What this means for you
So, in summation, on applying inventive step before the UPC, you need to:
- Identify the object of the patent, i.e. the objective problem, by looking at the subject matter of a claim as a whole and determine what problem it purports to solve based on the disclosure in the patent, including the technical data in the patent;
- Identify at least one realistic starting point, i.e., the closest piece of prior art; and
- Determine whether, on starting from the realistic starting point, the skilled person would be pointed or motivated to move in the direction of the claimed subject matter.
Of course, if the claimed subject matter is in the field of genetic engineering and biotechnology, then the last stage can be recast as follows:
3. Determine whether, on starting from the realistic starting point, the skilled person would be pointed or motivated to move in the direction of the claimed subject matter with a reasonable expectation of success.
Finally, the UPC Court of Appeal actually upheld Amgen’s appeal and overturned the Decision of the Central Division, which had held that the claimed subject matter lacked an inventive step. The UPC Court of Appeal held that there was no reasonable expectation of success in arriving at the claimed subject matter from the “realistic starting point”.
Author’s Case comment
I have to be honest, when you consider that the aim of the Unitary Patent was to bring legal certainty, it seems odd that the UPC Court of Appeal decided not to embrace the problem and solution approach, especially when it is used in a number of UPC countries and more importantly, by the EPO. When you consider the UPC Court of Appeal’s comment at section 124 of the Decision (see above), they obviously believe that there is no harm in adopting a different test, as all roads lead to Rome.
I would add that in the round, there is no real difference between the problem and solution approach and the UPC’s test in the sense that in 99.9% of cases when you are arguing under the problem and solution before the EPO, once you have identified the objective technical problem, you do run through the disclosure of the patent to reinforce the position that the objective technical problem is the same as that in the patent i.e. you do, in essence, argue that the objective technical problem and the object of the patent is one and the same thing. This is in support of the contention that there is no need to reformulate the objective technical problem.
With an eye on Article 25 of the UPCA, you can, of course, cite case law of the Boards of Appeal in support of an argument run before the UPC. It seems to me that the case law developed under the problem and solution approach is still relevant, and this is evidenced, for example, when you consider the UPC Court of Appeal’s approach to the concept of a reasonable expectation of success.
Ross Walker is a European Patent Attorney and European Patent Litigator by examination.
