T 2544/11 - Deleting feature is not broadening

Key points

• Published 21.10.2015. In the auxiliary request, the patentee had amended claim 1 by deleting "chemical" in " chemical cross-linking agents" . Does this contravene Article 123(3) EPC? The patentee had tried to rely on this term for novelty of the claims of the main request. The opponent argues that heat can also be used for cross-linking.
• The Board notes that " Further to the deletion of the term "chemical", the definition of the crosslinking agent specified in claim 1 of auxiliary request 2D further imposes that the crosslinking agent is selected from a specific list of chemical compounds. Therefore, the deletion of "chemical" is in fact compensated by the more specific definition now being present in claim 1."
• The Board further notes that there is no evidence on file that the term""chemical cross-linking agent" [] has any accepted definition or clear, unambiguous meaning in the art, in particular that it represents a limitation of the term cross-linking agent. There is in particular no evidence on file to corroborate the patent proprietor's argument, provided e.g. during the examination or opposition proceedings, according to which a "chemical" cross-linking agent is limited to those agents that are incorporated in the final cross-linked product." 
• Therefore, deleting the feature does not result in extension of the scope of protection and does not contravene Article 123(3) EPC. 

EPO T 2544/11 - link

Claim 1 as granted
"1. A process for the preparation of multiple cross-linked [deleted: derivatives of] hyaluronic acid (HA), which process comprises cross-linking HA via two or more different functional groups, wherein said cross-linking is effected by contacting HA with one or more chemical cross-linking agents so as to form two or more different types of functional bonds, between HA molecules, and wherein said two or more different types of functional bonds are selected from ether, ester, sulfone, amine, imino and amide bonds."

Claim 1 of auxiliary request 2D

"1. A process for the preparation of multiple cross-linked [deleted: derivatives of] hyaluronic acid (HA), which process comprises cross-linking HA via two or more different functional groups,
wherein said cross-linking is effected by contacting HA with one or more cross-linking agents so as to form two or more different types of functional bonds, between HA molecules, wherein said two or more different types of functional bonds are selected from ether, ester, sulfone, amine, imino and amide bonds,
wherein, in said process, a first cross-linking reaction is carried out and a further cross-linking agent, which may be the same or different from the first, is added to the reaction mixture to effect the second cross-link
and wherein the cross-linking agent is selected from formaldehyde, glutaraldehyde, divinyl sulfone, a polyanhydride, a polyaldehyde, a polyhydric alcohol, carbodiimide, epichlorohydrin, ethylene glycol diglycidylether, butanediol diglycidylether, polyglycerol polyglycidylether, polyethylene glycol diglycidylether, polypropylene glycol diglycidylether, or a bis-or poly-epoxy cross-linker."

Reasons for the Decision
[...]

Auxiliary request 2D

3. Art. 123(3) EPC

3.1 The sole objection raised by the opponent concerns the deletion in claim 1, as compared to granted claim 1, of the term "chemical" before "cross-linking agents".

3.1.1 According to the definition given above (see section 2.3.2), a crosslinking agent is a substance, i.e. a chemical compound, not heat or irradiation as argued by the opponent. Although it is agreed that crosslinking may be induced by heat and irradiation, there is no evidence on file that the skilled person would consider those means as substances, i.e. as "cross-linking agents". It is further questionable whether one would consider that heat/irradiation is "contacted with" hyaluronic acid when used, as specified in claim 1.

That reading is also in line with the meaning given to the term "cross-linking agent" in the application as filed: the last part of the paragraph bridging pages 4 and 5 of the application as filed reads "as described in more detail hereinbelow"; page 5, line 23 goes on with a list of chemical compounds suitable as crosslinking agents. Nowhere does the application as filed disclose heat or radiation for crosslinking.

3.1.2 The opponent argued that D17 (col. 15, lines 19-21) implicitly disclosed heat/radiation as crosslinking agents. However, that argument relies on one sentence present in a single patent document. Such a disclosure is not sufficient to depart from the general understanding of that term according to common general knowledge, which is illustrated by the definitions given in the technical dictionaries D13 and D14.

3.1.3 D15 and D16, both submitted by the opponent, relate to the meaning of the term "agent", which is defined as encompassing anything producing an effect. However, the term "agent" is more generic than the term "crosslinking agent" used in claim 1. D16 clearly shows that terms such as "adregenic blocking agent", "agent orange", "alkylating agent", "chelating agent" or "reducing agent" concern more specific definitions that are only related to "substances". On the basis of the evidence on file, it is concluded that, in the same manner, the more specific definition provided in D13 and D14 limits crosslinking agents to "substances" and excludes means such as heat or irradiation.

3.1.4 The passage of D3 (page 3, lines 46-50) relied upon by the opponent, also does not provide any definition of the term "crosslinking agent" but rather exemplifies heat or irradiation as "an agent which activates the carboxy function".

3.1.5 Further to the deletion of the term "chemical", the definition of the crosslinking agent specified in claim 1 of auxiliary request 2D further imposes that the crosslinking agent is selected from a specific list of chemical compounds. Therefore, the deletion of "chemical" is in fact compensated by the more specific definition now being present in claim 1.

3.1.6 However, there is no evidence on file that the term "chemical cross-linking agent" (emphasis by the Board) has any accepted definition or clear, unambiguous meaning in the art, in particular that it represents a limitation of the term cross-linking agent. There is in particular no evidence on file to corroborate the patent proprietor's argument, provided e.g. during the examination or opposition proceedings, according to which a "chemical" cross-linking agent is limited to those agents that are incorporated in the final cross-linked product. Such a definition would, in addition, be in contradiction with D14.

3.2 In that light, it cannot be considered to have been shown that the term "chemical" before "cross-linking agents" in granted claim 1 implied any limitation in respect of the meaning of the term "crosslinking agent" that would not be fulfilled by the definition of the crosslinking agents now being present in claim 1.

Therefore, it was not shown that the deletion (as compared to granted claim 1) of the term "chemical" before "cross-linking agents", effectively leads to an extension of the protection conferred by the patent in suit that would contravene the requirements of Art. 123(3) EPC.