Formulated for success: Patenting pharmaceutical formulations in Europe

Formulated for success: Patenting pharmaceutical formulations in Europe

Patent applications to pharmaceutical formulations can play an important role in patent strategies for drug products. Provided that the formulation is associated with an unexpected benefit, it can create opportunities for additional protection, even when the active ingredient is already known. This article outlines key considerations and best practices for patenting pharmaceutical formulations in Europe.
 

Novelty and inventive step

Production of a new formulation, for example through use of alternative excipients, creates a new composition of matter, provided that the exact formulation has not been disclosed previously.

Whilst trivial variations of known compositions are unlikely to be considered inventive in Europe, alternative formulations can be patentable if they show a surprising technical advantage. The surprising technical advantage of the new formulation can take many forms such as improving pharmacokinetics or bioavailability, allowing the drug to be administered by a different route, improving patient compliance, reducing side effects and/or reducing dosage frequency. The formulation may also have a key role in the delivery of a therapeutic, as demonstrated in recent years by the success of lipid nanoparticle (LNP) formulations which protect and deliver RNA therapeutics.
 
The field of formulation chemistry has developed significantly in recent years and much is known about the effect of standard excipients in pharmaceutical formulations. Therefore, reformulations which achieve predictable effects using well known excipients are unlikely to be considered inventive. However, even if a formulation may seem “standard” in hindsight, if the development of the formulation overcame particular challenges, this may be indicative of an inventive step. In general, if a formulation uses an unusual excipient or achieves a previously unattainable property then this could provide the basis of a robust inventive step narrative.
 

The importance of data

To improve the chance of successfully arguing for inventive step of a new formulation, it is advisable to include as much data as possible in the new application demonstrating an advantage of this new formulation. In particular, direct comparative data showing the benefit over known formulations or individual components can be very useful. The inclusion of both in vitro and in vivo data is likely to improve the chances of securing protection for the new formulation, particularly if the composition is similar to prior art compositions.


Key point: Wherever possible, include data demonstrating advantages of the formulation in the application at the outset. Possible advantages that can help secure protection include, for example, improving pharmacokinetics or bioavailability, allowing a different route of administration, improving patient compliance, reducing side effects, and reducing dosage frequency.


If there are limited data available on filing, it may still be possible to submit data later in prosecution to support an inventive step argument. However, if you expect that you may need to rely on post-filed data to demonstrate an effect, it is important to ensure that the effect is at least derivable from the originally filed application. Or, as it was put by the EPO’s Enlarged Board of Appeal in G 2/21, the effect should be “encompassed by the technical teaching and embodied by the same originally disclosed invention”. Whilst G 2/21 is still a relatively recent decision, current case law suggests that in some cases a bare assertion of a particular technical effect in the application as filed can be enough to justify the admittance of post-filed data (more detail here).
 
In practice, to maximise the likelihood of post-filed data being admitted, you could qualitatively foreshadow a specific improvement in a property by including statements of advantage explaining this, and then follow up later with quantitative post-filed data backing this up.


Key point: Post-filed data can be used to support inventive step. To maximise the likelihood of the data being admitted, consider including a qualitative statement regarding a technical advantage – but be specific! For example, if you expect a certain advantage to be associated with some, but not all, of the embodiments, consider mentioning the advantage specifically in relation to those embodiments.



The importance of fallback positions

Once a technical advantage has been established, the EPO will typically require that the scope of the claims be limited so that the effect is credibly achieved across the whole scope of the claims. In practice, this may mean having to limit the claims to specific components and narrow concentration ranges. Due to the strict approach adopted by the EPO in their assessment of added subject-matter, it is a good idea to draft the application with a generous number of fallback positions for the identities and concentration ranges of each component, all converging on the specific exemplified formulations in the application. If possible, explicitly recite each fallback position in combination with the others. One way of doing this is to include multiply-dependent claim-like clauses in the description, although in some cases even this might not be enough for the EPO’s strict approach. Setting out embodiments that combine all the key features in combination can be extremely valuable.


Key point: The scope for which the EPO is prepared to acknowledge inventive step may well be narrow. To be in the best position to meet the EPO’s very strict basis requirements when making amendments, make sure to include a variety of converging fallback positions in various combinations.



Clarity

The question of clarity arises frequently during prosecution of applications directed to pharmaceutical formulations. Due to the EPO’s strict approach to added matter, it can sometimes be difficult to remedy clarity issues after filing. It is therefore important to be aware of common pitfalls and ensure enough information is included at the drafting stage to avoid these.
 

Parameters

Pharmaceutical formulations are sometimes defined with reference to parameters, i.e. measurable physical or chemical properties. This can be the case, for example, when the formulation comprises a polymer, as polymers can be difficult to define on the basis of structural features alone.
 
When using parameters, it is important to be specific. A common example of a parameter, particularly in formulations comprising polymers, is molecular weight. However, given that there are several ways of measuring and expressing molecular weight that could lead to different results, specifying at least the type of molecular weight – e.g. weight average molecular weight (Mw) or number average molecular weight (Mn) – is key to satisfying clarity requirements.
 
In addition, the method for measuring a parameter typically needs to be included in the claim to avoid a lack of clarity. The EPO’s reasoning for this is that the skilled person must be able to easily and unambiguously verify whether they are working inside or outside the scope of the claim. Therefore, when drafting an application where a formulation can be defined with reference to a parameter, it is important to include a clearly defined method of measurement, drafted such that it can be introduced into the relevant claim.


Key point: When drafting patent applications for Europe, ensure that all parameters are specific and have a defined method of measurement, complete with as much detail as possible.


See our article on parameters at the EPO for more detail.
 

Trade marks

Pharmaceutical excipients are frequently defined by their trade marks. However, the use of trade marks in claims is generally not allowed at the EPO, as the identity of what is covered by the trade mark may change over time.
 
With that in mind, when looking to obtain protection for pharmaceutical formulations, it is important to ensure that the application as filed includes definitions that do not require the use of trade marks. For example, could the excipient be defined by its structural features? Additionally or alternatively, could it be defined by its physical characteristics using parameters (bearing in mind, however, to include measurement methods for any parameters)?


Key point: Avoid relying on trade marks to define the claimed pharmaceutical formulation. When drafting a patent application, define any components by their structural features and/or parameters.



Summary

Formulations play an important role in filing strategies for drug products in Europe. Formulation patents can provide strong protection for the approved drug or candidate product. The key factors to consider in Europe are whether the particular formulation provides an unexpected benefit, or overcomes specific formulation challenges, and how the formulation is defined.
 
For more information, please contact Johanna Viluma, Benjamin Heller, or your usual Kilburn & Strode advisor.

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