Biotech patents – assessing validity for broad claims

The 2020 ruling of the UK Supreme Court in Regeneron v Kymab made sense in context. The humanised antibodies that could be made using the methods described in the patent did not deliver enough useful outcomes to merit a monopoly over a whole field. However, there have been concerns about the way the decision was framed. Would it prove to be a sensible step forward, or would it cut the legs out from under too many biotechnology patents.

Sufficient disclosure?

The legal basis for the decision in Regeneron (discussed here) was insufficiency. The description set out in the patent did not disclose the invention clearly and completely enough for it to be carried out by an appropriately skilled person or team. Regeneron's claims covered a wide range of genetically modified mice, but the information given in the patent only enabled the skilled reader to make a small sub-section of them, and these were not particularly useful in practice. A range of products (transgenic mice) was included in the claim, but the teaching in the patent did not enable transgenic mice across substantially the whole range to be made.

The ruling raised concerns that this approach to insufficiency would act as a barrier to the patenting of “unlocking” inventions, especially where later developments turned out to improve their use and application. How would this play out in practice?

Regeneron applied

In a recent High Court decision (Illumina v MGI), we see Regeneron applied in a nuanced way that allows for the protection of significant biotech inventions without opening the door to overbroad claiming. The dispute involved patents based on work by Solexa, a spin out company from Cambridge University. Solexa was bought by Illumina in 2007. The defendants (MGI) were companies in the Beijing Genomics Institute group, said by Illumina to be offering infringing sequencing technology. 

The approach the judge adopted in Illumina v MGI was to separate “Regeneron relevant ranges” from other kinds of range. For a Regeneron relevant range, the claim will need to be enabled across the whole of the range, subject to minimal exceptions. So what is the difference between these two kinds of range?

A range that is not "Regeneron relevant"

This is a descriptive feature in a claim that might cover a variety of different things. But that variety does not significantly affect the value or usefulness of the claimed product or process in achieving its purpose.  

An example? A claim to a new shape of teapot spout that functions better (avoiding drips of tea after pouring, say). The claim says that the teapot can be made from any suitable material, and this could include a material yet to be invented. But this does not automatically mean that the claim is not enabled. The usefulness and purpose focuses on the spout shape, and not the material from which it is made.

A "Regeneron relevant range"

These are less common. Identifying a relevant range as discussed in Regeneron requires assessment of two things:

  • the invention as claimed, and
  • the essence or core of the invention.

The court must analyse whether the range included in a patent claim relates to the value, utility and purpose of the product or process claimed, and is “clearly relevant to the essence of the invention”. If the range in the claim is of this type, then enablement across all of it will be required.

So moving away from the tougher consequences of the Supreme Court’s analysis in Regeneron will require the patentee to convince a court that any ranges in their claims are not Regeneron relevant ranges. Although this assessment looks fairly straightforward in the Illumina case, we are not convinced that it will always be easy to apply.

The ranges in the Illumina patents

In the Illumina patents, several key claims included the terms nucleotide, polymerase, linker and detectable label. But the judge concluded that none of these ranges were the essence of the invention. That was a sequencing method whose utility derives from the use of a 3'-O-blocked nucleotide. Each of the nucleotide, polymerase, linker and detectable label needed to be suitable. However, beyond being suitable, the type chosen would not significantly affect the how the desired purpose would be achieved.

It would be possible to come up with options that would not work, although an expert team would have been able to make appropriate selections without too much difficulty.

Another claim involved a sequence read length from a single base up to any upper limit chosen. This read length was not a variable that significantly affected the value or utility of the claimed process. You could not conclude that sequencing more than one nucleotide was the essence or core of the invention of the claim.

Overall, the arguments that the claims contained Regeneron-relevant ranges, and were invalid for insufficiency, failed.

Points to note

  • Concerns that Regeneron would make it much harder to defend biotech patents from invalidity arguments have subsided after this ruling. The judge has explained how the reasoning in Regeneron can apply to different kinds of claim. Where the claimed range is right at the heart of the invention, enablement across the range will be necessary. However, other kinds of selection and choice will not make the claim insufficient as long as the skilled team can find suitable options without too much difficulty.
  • Although the ruling deals with concerns raised after Regeneron, it leaves both patentees and potential infringers with considerable uncertainty.
  • Those drafting patents will have a difficult task working out which side of the line any ranges in their claims will fall, especially at a point in time which could be many years before a court might look at it.
  • Those assessing freedom to operate will have similar difficulties. Where there is any kind of range in a claim, they will have to try to assess whether a judge will see it as the essence or core of the invention as a precursor to analysing whether the patent is valid.


Find out about our intellectual property and life sciences sector services.

Our content explained

Every piece of content we create is correct on the date it’s published but please don’t rely on it as legal advice. If you’d like to speak to us about your own legal requirements, please contact one of our expert lawyers.

Mills & Reeve Sites navigation
A tabbed collection of Mills & Reeve sites.
My Mills & Reeve navigation
Subscribe to, or manage your My Mills & Reeve account.
My M&R


Register for My M&R to stay up-to-date with legal news and events, create brochures and bookmark pages.

Existing clients

Log in to your client extranet for free matter information, know-how and documents.


Mills & Reeve system for employees.