Combinations of features in a claim must be “clearly and unambiguously” derivable from the content of the patent application as filed to comply with the EPO’s support and disclosure requirements of Art. 123(2) EPC. For example, a claim specifying a composition comprising feature a1 in combination with feature b2 may find verbatim support in the specification of the application as filed by the wording “said composition comprises feature a1 and feature b2”.
However, if such verbatim support is missing, e.g., features a1 and b2 can only be found separately, but not in combination with each other in the application as originally filed, the listing of the claim features a1 and b2 in the description as being “preferred” might be sufficient, as this is considered as a pointer to their combination (see e.g., T 1728/16).
Importantly, said advantage of the “preferred” wording, which allows to combine the separate but preferred claim features without contravening Art. 123(2) EPC, cannot be extended to claim features that were merely specified as “suitable” or described “purely by way of example” in the application as filed, as noted in the recent decision T 0531/19. In contrast to “preferably”, the “purely by way of example” and “suitable” wording used for the combined claim features in question on the relevant pages of the specification could not be considered as an indication or pointer for the skilled person to combine said claim features, and therefore the board concluded that the requirements of Art. 123(2) EPC were not met.