Patents: invalidity for obviousness

By Audrey Horton


The Court of Appeal has held that two drug formulation patents were invalid for obviousness.


To be a valid European patent, an invention must involve an inventive step (Article 52(1), European Patent Convention; section 1, Patents Act 1977) (EPC) (1977 Act). An invention involves an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art (Article 56, EPC; section 3, 1977 Act).

Obviousness must be considered on the facts of each case and the court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success. Generics (UK) Ltd v H Lundbeck A/S ([2007] EWHC 1040 (Pat)).


H brought an action for revocation of two of G's patents relating to the pharmaceutical formulations of the breast cancer drug Herceptin (trastuzumab). The disclosure of both patents was about making a lyophilised (freeze-dried) formulation with specific excipients.

The High Court held that both patents were invalid on the ground of lack of inventive step and added matter, and also refused proposed amendments to the patents. G appealed against the finding of obviousness and added matter. 


The court dismissed the appeal. It held that both patents were invalid for obviousness. As a result the court did not need to consider added matter.

Whether it was "obvious to try" to find a solution to the problem was not a substitute test for obviousness, but merely one of many considerations to be taken into account. There also had to be a reasonable or fair prospect of success. There was no single standard of what amounted to a fair expectation of success, which depended on all the circumstances and varied from case to case. 

The fact that the prior art disclosed that trastuzumab was in a phase II trial was sufficient motivation to cause a skilled team to embark on the project of formulating trastuzumab. The evidence showed a high degree of interest in trastuzumab by the time it was known that phase II clinical trials were underway, so the court's conclusion was justified.

It was not correct to say that the skilled person would only start on a lyophilised formulation if he found that a liquid formulation was not sufficiently stable. The patent explained that trastuzumab underwent degradation in solution, so it was at least plausible that there would be a degradation problem which could not be solved in the liquid form. As G had not displaced this natural inference by evidence to the contrary, the court could infer that trastuzumab could not be adequately stabilised in liquid form.

The court rejected G's argument that the High Court was not entitled to find that there was a fair or reasonable expectation of success. The High Court's judgment as a whole showed its assessment was that the skilled team had a fair expectation of success from the start.

An important issue was whether the correct question was whether the skilled person would, or whether they could, arrive at the claimed invention without inventive effort. A "would" test could be misleading as it was liable to bring in irrelevant considerations, such as whether it would be worthwhile commercialising an otherwise technically obvious product. 

It was not always necessary for the court to conclude that the skilled person, acting only on the basis of the prior art and his common general knowledge, would arrive without invention at the precise combination claimed. As the screening methods were part of the common general knowledge, the tests involved were routine, the excipients were common general knowledge and there was no reason in principle why a successful lyophilised formulation could not be made, it was clear that the claimed combination here was one that could be made by the skilled team. The question was whether this was the type of case where it was necessary to go further and ask whether the skilled person would necessarily have made the precise combination claimed.

In an empirical field it would rarely be possible to predict in advance that any individual experiment would work. In many cases, the fact a routine screening exercise could be carried out would be inadequate to establish obviousness. Still, here, the team would have a reasonable degree of confidence that a series of experiments would produce some that would work. To impose a requirement that the skilled team had to be able to predict in advance which would be the successful combinations was unrealistic and would lead to the grant of patents which in fact involved no inventive effort. Here, the skilled person would expect a range of different results, some good and some bad, but there was no invention in embarking on a screening process to pick out the good from the bad. The fact that it could not be said in advance which the good ones would be did not always prevent a finding of obviousness.


This decision illustrates the difficulties faced by owners of pharmaceutical patents seeking to extend protection for an important product by patenting specific formulations or dosage regimes. A formulation which could be reached by a skilled team using well-known techniques and components may not meet the requirement of inventive step. The patentee must be able to put forward evidence that in the particular circumstances there was no fair or reasonable expectation of success, or showing that the result was unexpected. In this context, the decision provides a useful clarification of the "could" or "would" debate.

The decision also shows the difficulty of challenging a finding of obviousness on appeal. It emphasises the importance of the court's assessment of the specific facts of each case. The High Court's decision on obviousness was not open to independent evaluation by the appeal court unless there was an error of principle.

Case: Hospira UK Ltd v Genentech Inc [2016] EWCA Civ 780.

First published in the September 2016 issue of PLC Magazine and reproduced with the kind permission of the publishers. Subscription enquiries 020 7202 1200.