CASELAW-EPO - reviews of EPO Boards of Appeal decisions

EP 3 286 308 B1 relates to process for preparing “(-)-Ambrox” or a “mixture comprising (-)-Ambrox”, by enzymatic conversion.

According to Wikipedia Ambrox is used in perfumery and has a scent with woody, musky and slightly salty nuances. Originally it is a natural product.

The patent is thus about a new way of synthesising it by enzymatic conversion..

Brief outline of the case

The OD found that the claims as granted were sufficiently disclosed and that claim 1 did not relate to “(-)-Ambrox” alone. The OD decided that various claims as granted lacked N over a series of documents. AR1 suffered the same defect. The patent was maintained according to AR2.

Proprietor and opponent appealed.

The board held that all claims on file were insufficiently disclosed as it claimed “(-)-Ambrox” alone.

The patent was revoked.

We look at claim 1 as granted. The same conclusion applies to the respective claim 1 of all requests.

The proprietor’s point of view

The proprietor argued that claim 1 should not be interpreted in isolation but rather in its proper context. The skilled person, reading the claim with a mind willing to understand, would construe it in the light of the patent disclosure as a whole and adopt the interpretation that makes technical sense and quoted T 190/99.

In particular, the skilled person would not construe the term “(-)-Ambrox” as being limited to chemically pure Ambrox, nor would they understand it as requiring the absence of any other reaction products. Rather, claim 1 related to the preparation of (-)-Ambrox as the principal product and did not exclude the formation or presence of by-products.

Where the starting material comprising 3E,7E-homofarnesol (EEH) was an EE:EZ isomer mixture, (-)-Ambrox was by far the predominant constituent of the reaction product and was thus obtained in an enriched form that could be processed further.

This interpretation was consistent with the patent specification, which repeatedly referred to the selective or predominant formation of (-)-Ambrox (e.g. claims 7 to 12). Accordingly, the term “(-)-Ambrox” should be construed as encompassing an enriched or predominant Ambrox product rather than requiring that (-)-Ambrox be the sole reaction product of the enzymatic conversion.

The proprietor further argued that, on the basis of the interpretation that the term “(-)-Ambrox” refers to an enriched or predominant product, Examples 5, 7 and 9 demonstrated that the claimed invention could be carried out and showed that the skilled person was able to reproduce the invention.

According to the proprietor, the opponent had failed to discharge its burden of proof, as it had not presented verifiable facts capable of raising serious doubts that the skilled person could produce (-)-Ambrox from a mixture of isomers comprising 3E,7E-homofarnesol (EEH), as required by claim 1.

The board’s decision

The board noted that claim construction must begin with the wording of the claim itself. Although the description may assist in interpreting ambiguous terms and resolving ambiguities, it cannot override clear claim language or deprive expressly claimed alternatives of their technical meaning.

As stated in T 190/99, a claim should be construed in a technically sensible manner and in the light of the patent disclosure as a whole. For the board, that principle does not justify an interpretation that deprives an expressly claimed alternative of its independent technical meaning.

In the present case, the expression “is enzymatically converted to (-)-Ambrox or a mixture comprising (-)-Ambrox” defines an essential feature of the claimed process.

By using the term “or“, claim 1 sets out two distinct alternative outcomes, namely “(-)-Ambrox” and “a mixture comprising (-)-Ambrox“. These alternatives cannot reasonably be regarded as synonymous. To do so would deprive the second alternative of independent meaning and render the term “or” devoid of purpose.

If the term “(-)-Ambrox” merely denoted the presence of (-)-Ambrox irrespective of whether additional products were formed, the second alternative “a mixture comprising (-)-Ambrox” would become redundant. Such an interpretation would run counter to the principle that claim language should, where possible, be construed so that each feature is given technical meaning.

The board therefore interpreted the expression “is enzymatically converted to (-)-Ambrox” as defining an enzymatic process by reference to a product outcome consisting of “(-)-Ambrox”, as distinct from an outcome in which (-)-Ambrox is formed together with other reaction products.

This interpretation is confirmed by the second alternative, which expressly covers embodiments in which the substrate is enzymatically converted to “a mixture comprising (-)-Ambrox”. This interpretation is also consistent with dependent claims 7 to 12, which differentiate between selective formation of (-)-Ambrox and embodiments involving additional reaction products, thereby reinforcing the distinction already apparent from claim 1.

The distinction between the two alternatives lies in the nature of the enzymatically formed products rather than in their degree of purity. Accordingly, the term “(-)-Ambrox” designates the product of the enzymatic conversion and does not, as such, imply chemical purity.

For the board, the technical meaning of the term “(-)-Ambrox” does not encompass an enriched or predominant product. While the patent appears to provide an enabling disclosure of embodiments in which isomer mixtures as defined in the claim are enzymatically converted by a SHC/HAC enzyme as defined in the claim into a mixture comprising (-)-Ambrox, this does not amount to an enabling disclosure of the distinct claim alternative requiring conversion into (-)-Ambrox alone.

Examples 5, 7 and 9 consistently show the formation of other products in addition to (-)-Ambrox.

The original application discloses only the production of mixtures comprising (-)-Ambrox and provides no teaching enabling the skilled person to avoid formation of the additional products and obtain (-)-Ambrox as the sole reaction product.

Neither the patent nor the CGK provides any guidance enabling the skilled person to identify enzyme variants, reaction conditions or other measures capable of preventing formation of the additional products while maintaining production of (-)-Ambrox as the sole reaction product. The patent contains no guidance towards achieving such selectivity.

Comments

In T 0190/99, catchword, the board held that “The patent must be construed by a mind willing to understand not a mind desirous of misunderstanding.”

It is interesting to note that the board reiterated the primacy of the claim, but acknowledged that the description may assist in interpreting ambiguous terms and resolving ambiguities, but it cannot override clear claim language or deprive expressly claimed alternatives of their technical meaning.

In substance, this is also what has been done in all decision applying G 1/24, but T 439/22-2 (gathered sheet). The clear meaning/interpretation of a claimed feature cannot be overruled by other meanings/interpretations found in the description.

I am not a chemist and thus unable to say whether from a purely chemical point of view, the decision is correct, but it is certainly correct from a mere logical point of view. In presence of two alternatives in a claim, each alternative has its proper meaning. If the skilled person is, on the basis of the original disclosure, not able to obtain one of the alternatives, then the subject-matter of the claim as a whole is insufficiently disclosed.

In view of the fact that the opponent had raised the problem of sufficiency as first ground of opposition and reiterated it when filing its appeal, one wonders why the proprietor did not file a request limited to a “mixture comprising (-)-Ambrox”.

T 1186/24