Introduction

The recent Supreme Court decision in Regeneron v Kymab has highlighted the risk-reward dynamic that exists for pharmaceutical and biotechnology companies that seek patent protection for innovations early in the discovery process.

The Supreme Court overturned the Court of Appeal's previous judgment, holding that Regeneron's patents, which related to transgenic mice platforms for the production of humanised antibodies, were invalid for lack of sufficiency. The Supreme Court found that if a claimed patent monopoly defines a whole range of products, all of the products within the 'relevant range' must be appropriately enabled by the patent specification. The decision is of great importance to the biotechnology and wider life sciences sector, as well as informing the approach in UK patent law more generally.

This decision serves as an important reminder that life sciences companies must carefully balance competing interests: filing to protect their inventions by way of patent rights as early as possible versus the risk of patent revocation at a later date in the event that they fail to disclose sufficient information to enable the inventions to be performed as claimed. At the heart of this case was the fundamental principle of the 'patent bargain' which requires inventors to fully disclose their technical contribution to the public in return for the grant of a period of exclusivity over the products or processes disclosed and is considered by many as essential to promote innovation.

This article considers the lengthy journey that this case has taken through the UK courts and its likely impact on innovation in the life sciences sector.

Facts

Regeneron and Kymab, both leading biotechnology companies, have been involved in a long-running dispute in numerous jurisdictions. The UK case centred on two of Regeneron's patents which concerned transgenic mice which produce hybrid antibodies containing both human variable (VDJ) regions and mouse constant regions, referred to as the 'reverse chimeric locus'. Regeneron relied on the reverse chimeric locus as the inventive concept of the patents disclosed in Example 3.

Regeneron alleged that Kymab's genetically modified mice (the 'Kymouse') infringed its patents on the basis that it contained a reverse chimeric locus, even though the Kymouse could only be produced due to improvements in methods that post-dated Regeneron's patents.

As was recognised by the English courts, Regeneron's technology was ground-breaking, but the dispute centred on whether its patents which purported to relate to that technology were valid and whether it was in fact entitled to the full extent of the monopoly it claimed. Kymab's counterclaim that the patents were invalid focused in particular on the concept of sufficiency under English patent law. Sufficiency requires that as part of the patent bargain, a patent specification must make the relevant invention available, comprehensible and workable, such that a person skilled in the art can put the invention into effect using the teaching in the patent. To the extent that it fails to do so, and the patent lays claim to subject matter beyond that which can be put into practice by the disclosure in the patent specification, the patent will be invalid.

Road to Supreme Court

In 2016 the High Court initially found in Kymab's favour. The late Mr Justice Carr in the High Court held that Regeneron's patented claims would have been infringed if valid, but found that the claims were insufficient. Carr held that, in view of expert evidence, the method provided in Example 3 would not have worked in the hands of an ordinary skilled person at the priority date of the patent (ie, the date of filing of the first application) without undue burden and innovation. The deletion and replacement of large pieces of DNA was simply not possible at the time of the invention. Carr therefore held the patents invalid.

The Court of Appeal overturned that decision in 2018. It ruled that the reverse chimeric locus would be likely to deal with immunological sickness in mice whose genes had "all or any" amount of human variable segments. Accordingly, the invention or technical contribution was a "principle of general application", even though some of the products covered by the claim could not be made at the priority date and the patent did not teach how to insert the full range of human variable genes into the mice.

Further, while the Court of Appeal agreed that Example 3 would not have worked, it held that a skilled person could use their common general knowledge to make obvious changes to the claimed invention. In particular, the court accepted that it would have been obvious to the skilled person to shorten the inserts to a manageable length (the 'mini-gene approach') and this approach would have been used to perform the invention without undue burden.

In the Court of Appeal's view, Regeneron had "clearly enough and completely enough" disclosed the patent claims. Therefore, the patents were valid and infringed by Kymab.

Supreme Court decision

Kymab appealed to the Supreme Court which, on 24 June 2020, reversed the Court of Appeal's decision and held the patents invalid.

While the Supreme Court again acknowledged Regeneron's ground-breaking technology and contributions to the biotechnology and wider life sciences sectors, it made it clear that if a claimed monopoly defines a whole range of products, the patent must enable all of those products.

The crux of the issue for the Supreme Court was whether a disclosure is sufficient if the teaching in the patent enables only some, but not all, of the products within the claimed 'relevant range'. The Supreme Court found the Regeneron patents insufficient because the patents in question only enabled the skilled person to make products across what it considered to be a small part of the deemed 'relevant range' within the scope of the claims. The Supreme Court differed from the Court of Appeal by holding that if the disclosure was held to be sufficient in this case, it would defeat the patent bargain, even if the invention amounted to a principle of general application.

Implications for life sciences innovation and patent filing strategies

This judgment was highly anticipated by the life sciences sector. The fact that the Supreme Court, comprising non-patent judges, overturned the Court of Appeal's judgment which was handed down by a panel including two of the country's leading patent judges (Lord Justice Kitchin and Lord Justice Floyd) has perhaps raised some eyebrows.

However, in reality, rather than marking a departure from the previous approach, the Supreme Court has clarified the basic principles of sufficiency – namely, that a patentee should claim no more than is commensurate with its contribution to the art. This is vitally important in dynamic industries in which innovative developments may be curtailed by a monopoly granted to an inadequately disclosed invention.

One of the key aspects arising from this decision is a renewed focus on the best strategies in terms of patent filing, prosecution and enforcement for the life sciences and biotechnology sectors. This is crucial where innovation and competition drives filing strategies and access to funding for further research and development or commercialisation is often contingent on having IP rights and the ability to exclude competition for a prescribed term.

The clear message from the reasoning of the majority in the Supreme Court is that applicants take a risk if they file patent applications too early based on aspiration and not technical contribution. The risk-reward dynamic can be challenging for patentees and, in particular, biotech companies which often grapple with when to file. Filing too early may mean that they are unable to protect the full scope of their contribution, while filing too late may mean that they are unable to secure investment and fully develop their technologies.

Similarly, filing claims which are too broad in scope is likely to lead to sufficiency challenges and a higher risk of the patent being held to be invalid if challenged. Competitors may therefore be emboldened to challenge patents which have broad claim scopes or ranges.

At its simplest, it will be harder to enforce and easier to challenge patents where nothing more than de minimis products falling within the scope of the patent can be made. Unless a patent relates to a simple product, there may be more challenges succeeding on sufficiency grounds. Parties challenging patents may perhaps be more confident in raising lack of sufficiency arguments where a patent contains only prophetic examples, or it is known that not all products falling within the scope of the relevant claims could have been made at the priority date. Therefore, although the law in respect of sufficiency remains largely unchanged, parties may feel encouraged to raise such grounds. Further, there are clearly areas of the judgment which lend itself to further areas of dispute, for example, as to the meaning of 'relevant range'.

While patent practitioners continue to digest this judgment and its implications, Kymab can claim a well-fought victory in the United Kingdom. In the meantime, the global dispute between these two biotech powerhouses rumbles on.