The recent decision in T 0722/24 is an example of effective patent strategy for a clinical stage product. Pharmaceutical innovation involves far more than identification of a therapeutic molecule. Over the course of a drug's life cycle, there is the need for considerable and lengthy further development, leading to new inventions. This innovation leads to new patentable inventions, including finding the therapeutically safe and effective dose, developing the pharmaceutical formulation, and finding precision medicine approaches. However, these types of invention are also often challenged on the grounds that they merely constitute a routine part of the drug development process (IPKat). In these cases, invention capture is primarily about documenting the myriad of challenges that needed to be overcome to reach the clinic, even if these don't make it into the regulatory submissions. The Patentee in T 0722/24 was able to convince the Board of Appeal that their formulation was "outstanding" at solving a difficult problem in formulation development.
Case background
The patent at issue EP 3725778, owned by Medivation Prostate Therapeutics and Astellas Pharma, relates to a solid pharmaceutical composition of the prostate cancer drug, enzalutamide. A total of eleven opponents challenged the patent, but the Opposition Division ultimately upheld the granted claims. Claim 1 of the main request on appeal defined a solid pharmaceutical composition comprising a solid dispersion containing amorphous enzalutamide and the concentration-enhancing polymer HPMC-AS. Enzalutamide is marketed as XTANDI for the treatment of prostate cancer, and is a multibillion dollar product.
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| Formulation development |
New formulation
The main issue on appeal was inventive step. The Board of Appeal identified the closest prior art to be the prescribing information for the commercial product XTANDI. This product was a liquid-filled soft gelatin capsule containing enzalutamide dissolved in a solvent. The claims of the main request on appeal were found to differ from the prior art in that they defined a solid pharmaceutical composition comprising a solid dispersion of amorphous enzalutamide with a specific polymer, hydroxypropyl methylcellulose acetate succinate (HPMC-AS).
The key question for the Board of Appeal was what technical problem was solved by this change in formulation. To support their inventive step argument, the Patentee argued that the claimed invention embodied a combination of three distinct effects. First, argued the Patentee, there was an effect of convenience, whereby the claimed solid dispersion formulation allowed for more convenient dosing. Second, the new formulation was purported to provide no loss in bioavailability compared to the prior art. The patent contained data from bioavailability studies in humans showing that the claimed tablet achieved an area under the curve (AUC) comparable to the XTANDI capsules. Finally, the Patentee submitted that the composition demonstrated "outstanding" physical stability. The Patentee pointed to data in the patent showing that the amorphous form of enzalutamide was remarkably stable, even under harsh conditions.
Beyond compare
The Enlarged Board of Appeal decision in G2/21 addressed head-on an issue at the heart of the problem-solution approach to inventive step, whereby a Patentee may need data comparing their invention to the prior art, but may not have known of the existence of the prior art when the patent was filed (IPKat). This problem is particularly acute for antibody inventions, where the technical problem to be solved may be very narrow. However, it also applies to other fields involving iterative innovation within a crowded field, including software (IPKat). The decision in this case is remarkable for the Board of Appeal observation that comparative data was not needed with respect to the stability effect relied on by the Patentee. The Board of Appeal particularly found that the "outstanding" effect of the claimed formulation was so good, that a direct comparison with the prior art was deemed unnecessary and that the lack of a direct comparison could not justify disregarding this property of the formulation (r. 5.2.4).
Content with the data, the Board of Appeal went on to formulate the objective technical problem as the provision of a further pharmaceutical composition of enzalutamide freed from the practical constraints of the XTANDI capsules, exhibiting comparable bioavailability in humans, and with outstanding physical stability.
The Opponents argued that using HPMC-AS to formulate a poorly soluble drug into an amorphous solid dispersion was a well-known and obvious strategy. They pointed to a host of prior art documents that described HPMC-AS as a uniquely effective and broadly applicable polymer for this exact purpose. However, the Board of Appeal was not convinced by these arguments. The Board of Appeal instead gave significant weight to other documents, which painted a picture of a field still reliant on a "tedious trial-by-error approach" (r. 5.3.3). For the Board of Appeal, these documents underlined the persisting difficulty and unpredictability in developing stable and effective amorphous solid dispersions. Interestingly, the Board of Appeal noted that whilst many compounds had been successfully formulated in the lab, products reaching the market remained the exception.
The Board of Appeal thus found that the prior art did not provide the skilled person with a reasonable expectation of success that using HPMC-AS for enzalutamide would solve the multi-faceted objective technical problem of achieving comparable bioavailability and outstanding stability in a more convenient dosage form. The Board of Appeal concluded that the solution was therefore not obvious, and the appeals were dismissed.
Final thoughts
A challenge for invention capture in this space, is the different priorities and requirements of regulatory submissions and patents. In this case, the Patentee successfully framed the invention not as a simple, obvious development of a new formulation technology, but as an effective solution to a complex, multi-variable challenge in a difficult field. However, for a regulatory submission, there is little to no incentive in outlining all the trials and tribulations that went on behind the scenes in order to arrive at a new formulation. All that matters for the regulatory process is that the commercial and clinical embodiment of the formulation has the properties that it needs. The challenge for the Patentee is to remember all the challenges that were overcome in development, even if these don't get a mention in the regulatory documents, so that the invention story is not lost.
This case also joins the now long list of decisions to apply G2/21. As attention turns to the latest Enlarged Board of Appeal referrals and decisions (G1/23, G1/24 and the recently announced G1/25 (IPKat)), it is interesting to see how commonplace and routine the application of the EBA's reasoning from a previous referral has now become. The EBA order in G2/21 was self-confessedly "vague". However, the Boards of Appeal have generally found few issues with working out how to apply it (IPKat). As we have seen with the recent decisions applying G1/24, Boards of Appeal strive hard to fit decisions from the EBA as much as possible within the framework of the existing case law (IPKat).
Further reading
- Second medical use dosage regimen claim successfully traverses both insufficiency and "obvious-to-try" attacks (T 0799/16) (Mar 2021)
- Crystal clear? G 2/21 applied to polymorph patents (T 1994/22) (Jul 2024)
- Functional claims for pharmaceutical formulations: Validity versus enforcement (T 2130/22) (Jan 2025)
Reviewed by Dr Rose Hughes
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Monday, August 25, 2025
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I also commented this decision in my blog, but under a different perspective.
ReplyDeleteDecision of a court in a contracting state
In its argumentation, the proprietor referred to a judgement of the District Court of The Hague, to support its point of view.
The proprietor insisted upon the fact that the Dutch Court upheld the EPO Main Request in The Netherlands, following invalidity proceedings brought by the Dutch company Synthon.
The Board observed that the instances of the EPO may generally take notice of decisions from other jurisdictions, either ex officio or following the submission by a party. This applied in particular to the Dutch decision.
The board acknowledged that it is a Court decision from a contracting state on the validity of the same European patent, in view of the same prior art as that under consideration in the present appeal proceedings.
However, due to the nature of legal proceedings, the facts and outcome of a decision from another jurisdiction cannot to be regarded as evidence on which a pending case is to be decided.
In other words, a Board of Appeal did not consider itself bound by a decision of another jurisdiction, even if the patent and the prior art used against the patent are the same. IMHO, this is right so, and does not fall under the requirements of Art 125.
The position of the Board in the present case is in clear contrast with the view expressed by the CoA UPC in UPC_CoA_22/2024, when it refused a stay of the proceedings before the UPC in view of parallel opposition proceedings before the EPO.
In this decision, the UPC-CoA made it abundantly clear that, in the interests of harmonisation, it actually requires the subsequently deciding body, to take over what has been decided by the first deciding body. The attitude of the UPC-CoA is clearly against the right of each jurisdiction to freely decide on the evidence before it.
Application of G 1/24
It is also true that, in recent decisions applying G1/24, Boards of Appeal strive hard to fit decisions from the EBA as much as possible within the framework of the existing case law. See for instance T 400/23, Reasons 3.4.2, 4.4.1 and 4.4.2; T 1465/23, Reasons 2.4; T 1561/23; Reasons 2.10; T 1846/23 Reasons 1.5.4.
In all those decisions the Boards held that the interpretation of a claimed feature, clear as such for the skilled person, cannot be overruled by a different interpretation of the same feature given in the description.
In T 1164/23, the proprietor argued that argued that the subject-matter of the patent extends to what, after examination of the description and the drawings, appears to be the subject-matter for which the patent proprietor seeks protection, i.e. the will of the proprietor. The board disagreed, and held the intermediate generalisation not allowable and added, cf. Reasons 1.5.5, that G 1/24, did not alter this conclusion.
The notion of “directly and unambiguously derivable, is according to T 1164/23, not impaired by G 1/24.
So often EPO oppositions are essentially decided by what the definition of the problem to be solved is, and there are different strategies for opponent and patentee in terms of whether to define a broad simple problem or a narrow and complex one. Prior art is easy to analyse, but it can sometimes be very difficult to define what exactly the Examples have achieved and to what extent they can be supplemented by post-filing data (filed by patentee or opponent). The good patent attorney can process all these factors and end up with the optimal statements of what the contribution is, what the problem to be solved is, with an eye to possible future amendments that could be made, without it sounding artificial and far-fetched. This is where the more aggressive parties lose out as they cannot balance all the different aspects properly. Thank you for an excellent writeup.
ReplyDeleteInventive step evaluations of formulation patents are always weird to me. For every drug molecule the task is to develop a pharmaceutical composition for administration, ideally for oral administration. Still patents are granted and uphold that use common knowledge excipients for exactly this purpose as described by the common knowledge. Its like inventing a new engine for a car and (after the engine has been published) patents are granted for a car with this new engine and a known type of breaks. According to EPO / BoA this would not be enough to see a reasonable expectation of success (and deny an inventive step) to use the known breaks for their known purpose, because the breaks have not been used with the new engine so far. Or in other (pointed) words: There is no requirement for inventive step for formulation patents. Only novelty is required.
ReplyDeleteHi Anonymous. Your comment reflects common sense, but you may find the UK Court of Appeal decision in the Leo/TEVA case helpful in understanding what is happening (see link below). A very respected UK judge (Jacob) reversed an obviousness decision by the brilliant Judge Birss who had looked at the facts in the same way you describe in your comment. Something can be routine 'to try', but unless the correct type of predictability is present it is still inventive, and that is how the UK Courts and EPO presently think about such inventions. [I don't think this is fair but this is simply how the world works]
Deletehttps://www.bailii.org/cgi-bin/markup.cgi?doc=/ew/cases/EWCA/Civ/2015/779.html&query=LEO+and+TEVA&method=boolean
Thank you Santa for the reading suggestion. That was indeed nice to read and helpful.
Delete"First, argued the Patentee, there was an effect of convenience, whereby the claimed solid dispersion formulation allowed for more convenient dosing." As the first argument! Made me laugh and assume the attorneys didn't believe the claims were inventive themselves. There could be something in the 2nd argument depending on the facts, but, with those facts, I doubt the skilled person would be surprised that bioavailability was comparable. The 3rd argument is the key (just my personal opinion, and not having read anything related to the case). Obtaining stability of any formulation of an amorphous form is far from certain, ever.
ReplyDeleteThe development of many formulations is just routine, as has been demonstrated in the courts of many jurisdictions, however, this doesn't mean it is in all cases. If otherwise, the patent offices and courts would not need to ever even glance at the facts. Much to the disdain of many, such secondary patents may cover important innovations.
Well the pharmaceutical industry is closely looking at whether the UPC will maintain patents to formulations (secondary patents/inventions) or whether they will be found to lack inventive step. If the UPC decides to revoke too many in litigation then the opt out system will continue beyond the 7 years presently scheduled, I predict, until the UPC case law becomes more favourable for this type of invention. This is essentially the reason why we have the opt out system.
Delete