T 1065/23 – on novelty and inventive step of pea protein extracts

Product-by-process claims can be a valuable tool for claiming products that are difficult to define in terms of structure or measurable physical properties.  In the chemical field, they are particularly relevant for materials such as polymers and natural extracts. 

Such claims are typically drafted in the form of: ‘product A obtainable by process B’.

A recent decision from the Technical Board of Appeal of the EPO (T 1065/23) serves as a reminder that robust experimental evidence demonstrating that a particular method step imparts specific properties to the claimed product can put an applicant/patentee in a strong position when arguing novelty and inventive step in relation to a product-by-process claim.

Background: EPO practice and product-by-process claims

Under EPO practice, product-by-process claims are construed as claims to the product as such.  It does not matter whether the claim refers to a product “obtainable”, “obtained” or “directly obtained” by a given process – the claim is still interpreted as covering the product per se.

Product-by-process claims may be tricky to prosecute or defend before the EPO.  During prosecution, the applicant might have to persuade the Examining Division that such a claim is novel over a prior disclosure of a similar product obtained by a different method.  Under EPO practice, a product-by-process claim is not considered to be novel merely because the product in question is made by a novel process.

Instead, novelty stems from the technical properties imparted to the product by the process by which it is made.  Is the claimed product identical to that disclosed in the prior art or can differences between the products be identified?  Does the process (defined in the product-by-process claim) in fact result in a product that can be distinguished from the known product(s), for example, due to differences in properties of the products? In an ideal scenario, it would be possible to show that a particular step (or sequence of steps) imparts specific properties to the claimed product that set it apart from the prior art product(s).

If a lack of novelty objection is raised, the burden of proof rests with the applicant to demonstrate to the Examining Division that the claimed product differs from that of the prior art, and in the absence of suitable data in the application as filed (or any helpful passages in the application or the cited prior art), it might be necessary to submit supplementary experimental data to address such an objection. 

On top of that, the applicant may have to justify the use of the product-by-process format in the first place.  Indeed, the Guidelines for Examination at the EPO stipulate that this format can only be used “if it is impossible to define the claimed product other than in terms of a process of manufacture”.  If the Examining Division considers that doing so is not “impossible”, they will likely raise a lack of clarity objection.

The decision

Claim 1 of Auxiliary Request 1 (AR1) defined a method for extracting pea proteins from an aqueous composition comprising pea proteins.  The method included the step of adjusting the pH of the aqueous composition to a value of from 4.0 to 5.8 to form an aqueous slurry comprising precipitated pea proteins.  The aqueous slurry was then subjected to a heat treatment (step (d) of claim 1) at a temperature of from 75 to 210 °C.

Step (d) of claim 1 required that the aqueous slurry be subjected to the heat treatment has a pH of from 4.0 to 5.8.

Claim 1 of AR1 also set out a number of alternative conditions (heating temperature and heating time) in respect of step (d).

Claim 10 of AR1 (a product-by-process claim) defined a pea protein extract obtainable by the method according to any one of the preceding claims (i.e. including that of claim 1).

Claim 11 of the granted claims (a product per se claim; not present in the claims of AR1) defined a pea protein composition having (i) a particular protein content and (ii) nitrogen solubility index at pH 7.0 of at most 15%.  This claim did not survive the opposition-appeal proceedings – it is included here for reference only.

Novelty

None of the cited documents were held to directly and unambiguously disclose the combination of method steps of claim 1.  In particular, step (d) of claim 1 was not disclosed.

Turning to product-by-process claim 10, the Board acknowledged that numerous examples in the patent show that pea protein extracts subjected to step (d) of claim 1 have a significantly lower nitrogen solubility index, gel strength and viscosity than those which are (i) heated at a different pH or (ii) are kept at the claimed pH but are not subjected to the claimed heating step.  In addition, the data in the patent showed that pea protein extracts obtained by the claimed method have improved wine-fining and baking properties.

The patentee also filed additional experimental evidence during the opposition proceedings to demonstrate that the desired properties are obtained using the claimed method.

The Board thus held that step (d) has a significant impact on the physicochemical properties of the obtained pea protein extracts. Crucially, the Board considered that the evidence makes it credible that the pea protein extracts obtained by the claimed method differ from those not obtained by that method.

A number of allegedly novelty-destroying documents were cited against claim 10.  Some documents apparently showed pea protein compositions having the same nitrogen solubility index as defined in claim 11 as granted (i.e. at most 15% at pH 7.0; see above).

The Board dismissed all of them on the basis that there was no evidence on file that the prior art extracts necessarily had the improved physicochemical properties of the products obtainable by the claimed method.  The Board emphasised that step (d) of claim 1 imparts special characteristics to the claimed extracts, i.e. improved viscosity and gel strength, as well as advantageous properties when used in baking and wine-fining, which properties extend beyond the specific nitrogen solubility index.  The Board even said that there is no evidence that the prior art products were prepared by carrying out step (d) of claim 1 (this reasoning would likely not have applied had the link between step (d) and specific improved properties not been established).

Inventive step

Having proved that step (d) imparts specific improved properties to the products, the patentee enjoyed a relatively smooth path through the discussion of inventive step.  The closest prior art did not disclose step (d) of the claimed method, and there were no cited documents that could remedy this deficiency within the framework of the EPO’s problem-solution approach.

That said, one point is perhaps worth mentioning.  One of the opponents argued, with reference to an experimental report, that the particular pH range of 4.0-5.8 in step d) of claim 1 was arbitrary.  This was allegedly because the report showed that, while the preferred low nitrogen solubility index of at most 15% (as in granted claim 11, see above) is obtained inside the specific pH range, it was also obtained outside that range, e.g. at pH of 3.8 or pH of 6.2.

The Board noted the following:

- firstly, the same experimental report shows that all protein extracts heated at pH = 6.2 have a higher nitrogen solubility index than those heated at a pH within the claimed range.  In other words, lower solubility index is obtained by working within the claimed range.  This is what is relevant, rather than whether the values obtained for pH = 6.2 are within the range of “at most 15%”.

- secondly, the proprietor’s experimental evidence shows that, when the heating step is carried out at a pH of 3.8, this leads to disadvantageous viscosity and gel strength properties.  Those features are relevant – they characterise the obtained product and its improved properties [for pH = 3.8, lower solubility index values could be seen than those for pH values inside the claimed range]

The Board thus noted that “[t]he fact that the cut-off values 4.0 and 5.8 of the claimed pH range might exclude lower or higher pH values suitable for achieving advantageous effects is not, as such, a reason to consider the selection of the claimed cut-off values "arbitrary" […]

it would be illogical if a claim defining a feature by reference to a range be considered to lack an inventive step for the sole reason that the invention could have been claimed more broadly, specifying a broader range.”

Summarising, the Board said that what is relevant in the context of inventive step is that the available evidence makes it credible that subjecting a slurry containing precipitated pea protein at a pH within the claimed range to the claimed heating step induces effects which go beyond those obtainable by carrying out the method of the prior art and that there is evidence that both the claimed heating and the pH are relevant for inducing that effect.

Conclusion

In T 1065/23, the specification of the patent in suit placed clear emphasis on the fact that the methods used for extracting and isolating proteins can significantly affect the physicochemical and functional properties of the resulting protein extracts. This point was supported by experimental data already included in the application as filed. 

The patentee reinforced this position by filing additional evidence during the opposition proceedings, further underlining the link between process steps and resulting product properties.

All of this made it easier for the patentee to rely on that link and set the scene for discussing novelty and inventive step.  It was also helpful that the patentee could rely on multiple improved properties, rather than just one.

Claim 11 as granted (the product per se claim) did not survive the opposition-appeal proceedings (it was considered to lack novelty).  Thus, product-by-process claims can be a useful tool when a product’s defining characteristics are intrinsically linked to how it is made.  While such claims can face added scrutiny, they may offer a viable route to protection where conventional product claims fall short.

If you have any questions about prosecuting, attacking, or defending product-by-process claims, feel free to get in touch.

This article is for general information only and is not intended to constitute legal advice. If you would like tailored advice on a specific matter, please do not hesitate to contact me.