The concept of “relevant ranges”, discussed by the UK Supreme Court in Regeneron Pharmaceuticals Inc v Kymab Ltd [2020] UKSC 27 (Regeneron) and reinforced in Illumina Cambridge Ltd v Latvia MGI Tech SIA & Ors [2021] EWHC 57 (Pat) (Illumina), has recently emerged as a significant issue in Australian patent law.  Kat friend Claire Gregg (Davies Collison Cave) is here to 
report on the view from Australia.  

Over to Claire:

"Challengers to the validity of patents and patent applications in Australia are increasingly invoking the “relevant range” concept, but the application of the principles in Regeneron can have serious implications for claims that rely on a principle of general application and may arguably conflict with the fundamental tenets of the patent system.

“Relevant ranges” infiltrate Australian patent law

Australia's law on sufficiency is based on UK law, requiring the specification to disclose the claimed invention in a manner that is clear enough and complete enough to enable a skilled person to perform the invention across the full width of the claims without undue burden or further invention.[i]

In 2023, the Full Federal Court of Australia in Jusand Nominees Pty Ltd v Rattlejack Innovations Pty Ltd [2023] FCAFC 178 (Jusand) endorsed the UK Supreme Court’s approach to the assessment of sufficiency in Regeneron, which first introduced the concept of “relevant ranges” into UK law. Essentially, a “relevant range” is any (explicit or implicit) range within a claim that “significantly affects the value or utility of the product in achieving the purpose for which it is to be made”.[ii] In that regard, the Full Court in Jusand stated:[iii]

… the relevance of a range [is] judged against the invention as claimed and, where appropriate, against its essence or core where that is understood to be related to the technical contribution the specification makes to the art and/or its inventive concept. 

While the principles in Regeneron were previously endorsed by the Federal Court, [iv] the Full Court in Jusand was the first to apply these principles in finding that a descriptive or functional feature in a claim was not sufficiently enabled (and lacked support).

The invention at issue in Jusand was a safety spear device for protecting against the hazard of drill rod failure in a drilled rock bore comprising an anchor member and an impact reduction member, which functioned by converting downward weight force into lateral braking forces. The Full Court found that the material selection for the anchor member feature, which the specification taught how to make from steel, was a “relevant range”, and that there were materials other than steel (including plastic, having regard to an alleged infringing product) that could plausibly be used to carry out the invention. However, the evidence established that to make the invention from materials other than steel required undue burden and inventive skill.

Since Jusand, parties seeking to invalidate an application or granted patent that includes a claim involving an explicit or implicit range have increasingly argued that it includes a “relevant range”.[v]

The relevance of “relevant ranges”

“Relevant ranges” present a particular problem for certain ranges within a claim that rely on a principle of general application, including descriptive or functional features, to which two of the eight principles set out by Lord Briggs in Regeneron at [56] are pertinent:

(vi) Patentees may rely, if they can, upon a principle of general application if it would appear reasonably likely to enable the whole range of products within the scope of the claim to be made. But they take the risk, if challenged, that the supposed general principle will be proved at trial not in fact to enable a significant, relevant, part of the claimed range to be made, as at the priority date.

(vii) Nor will a claim which in substance passes the sufficiency test be defeated by dividing the product claim into a range denominated by some wholly irrelevant factor, such as the length of a mouse’s tail. The requirement to show enablement across the whole scope of the claim applies only across a relevant range. Put broadly, the range will be relevant if it is denominated by reference to a variable which significantly affects the value or utility of the product in achieving the purpose for which it is to be made. 

Shortly after Regeneron was decided, Birss J (as he then was) further considered “relevant ranges” in Illumina Cambridge Ltd v Latvia MGI Tech SIA & Ors [2021] EWHC 57 (Pat) (Illumina), helpfully stating:[vi]

Once the concept of a relevant range is properly understood, I think it will be an unusual case in which the kind of ordinary descriptive or functional language one sees in most patent claims will be regarded a relevant range in the Regeneron sense.

In that regard, Birss J articulated a further slew of principles pertaining to “relevant ranges” in Illumina, including the following at [279]:

(iv) An example of [a] range, not relevant in the Regeneron sense, will be a descriptive feature in a claim (whether structural or functional) which can cover a variety of things, but for which that variety does not significantly affect the value or utility of the claimed product or process in achieving its relevant purpose. The relevant purpose is judged in all the circumstances, starting from the terms of the claim itself but also, where appropriate, by reference to the essence or core of the invention.

(v) For a claim feature which amounts to a range in this other sense, the skilled person must still be able to make a suitable selection, without undue burden, in order for the claim to be sufficiently disclosed. However provided that is so at the relevant date, such a claim feature will not be insufficient simply because it is capable of also covering within its scope things which had not been invented at that relevant date. 

While the decision in Illumina appeared to have resulted in the UK courts applying the “relevant range” concept sparingly, it recently reared its ugly head in DSM IP Assets BV & Anor v Algal Omega 3 Ltd [2025] EWHC 675 (Pat) (DSM).

The claims at issue in DSM were directed to a crude thraustochytrid microbial oil extract having a high docosahexaenoic acid (DHA) concentration, whereas the specification only taught how to obtain such an oil from one thraustochytrid strain. The choice of thraustochytrid strain was considered a “relevant range” because the DHA concentration, which affected the value or utility of the invention, varied significantly between strains. As the specification did not teach how to identify or obtain other thraustochytrid microbial oil extracts having a high DHA concentration, the claims were found to lack sufficiency.

The problem with “relevant ranges”

The characterisation of a claim feature as a “relevant range” is not problematic per se; the real issue arises from the related principle (vi) of Regeneron, which introduces a retroactive assessment of sufficiency. This is so even where a “relevant range” arises from an “ingenious” innovative concept (cf. Jusand).

The problem is best illustrated by reference to selection inventions, which, under the Regeneron principles, can threaten the validity of a patent for the original invention. This is fundamentally at odds with the patent bargain, which requires publication of the invention prior to grant of a patent precisely so that others can utilise it for further innovation. The problem also arises in relation to priority entitlement, which also involves an (external) sufficiency analysis in Australia.[vii] Applying Regeneron, a priority claim may be rendered bad not only by a later selection invention but by an updated disclosure in the priority-claiming application, including to satisfy the “best method” requirement under Australian law.

For these reasons, sufficiency (and support) should be assessed as at the relevant date (the filing date for internal sufficiency and the priority date), as was the case in Australia prior to Jusand and in the UK prior to Regeneron. However, the UK Supreme Court considered this approach problematic because “[t]he essential patent bargain is not satisfied in relation to products in that part of the range which cannot be made, using the teaching in the patent”.[viii]

However, consider Jusand, where the Full Court acknowledged that the innovative concept underpinning the invention was the “ingenious conversion of downward weight force into lateral braking forces”; the claims were invalid for lack of sufficiency because the invention included a second problem to be solved in the material selection for the anchor member. It is likely the second problem could not have been solved without the patentee's contribution to the art. In that case, the patent system ought to (and prior to Regeneron, did) enable whoever solves the second problem to protect their invention without invalidating the patent for the original invention upon which it is based.

This was effectively the approach endorsed by the England and Wales Court of Appeal (EWCA) in Regeneron Pharmaceuticals, Inc v Kymab Ltd & Anor [2018] EWCA Civ 671, which was summarised (and dismissed) by the Supreme Court in Regeneron at [27]:[ix]

… The patent bargain requires that the reward given to the patentee should be commensurate with the contribution which the invention makes to the art. An invention which consists of a new generally applicable principle may contribute to the art by its use, not only in products which can currently be made, but equally in products which will only be capable of being made in the future, after further inventive research and development. To limit the patentee strictly to a monopoly over the products which can immediately be made would be to deprive the patentee of any reward for the public benefit which will be derived from the use of that same invention in future types of product. In a fast-moving field, where new products quickly outperform their predecessors so as to render them obsolete, the reward of a monopoly limited to those immediately capable of being made would be short-lived and illusory. Accordingly the invention should be regarded as sufficiently enabled across the range if it can be seen that it will in due course benefit all products in the range, provided that, as at the priority date, the teaching in the patent enables at least one type to be made immediately. 

Concluding remarks

The “relevant range” concept has, at present, infiltrated Australian patent law, and does not appear to have faded into the background in the UK as previously hoped. The Australian judiciary seems determined to follow Regeneron with little regard to its consequences, and the Australian Patent Office is compelled to follow.

This author would argue that the approach taken by the EWCA was correct, at least in circumstances where the applicant has made a genuine contribution to the art. However, while the ideal situation is one in which a patent cannot be invalidated merely because it was established at a later date that an embodiment within a “relevant range” was not enabled by the original disclosure, a change in approach in Australia is likely to require either High Court intervention or a fundamental shift in UK law (e.g., a reconsideration of Regeneron by the Supreme Court).

While “relevant ranges” do not fundamentally change the test for sufficiency in Australia (or the UK), until the retroactive assessment of sufficiency is quashed, it is important to consider whether it is necessary to characterise a claimed feature as a “relevant range”, so as to avoid creating a legal landscape that becomes overly onerous for patentees to navigate and is out of step with the patent bargain."

Source: https://ipkitten.blogspot.com/2025/09/the-emergence-of-relevant-ranges-and.html