c) Additional prior-art search necessary 

The following cases were remitted to the department of first instance for an additional search.

In T 1159/15 the board, referring to the established case law, held that a prior-art search should have been carried out before refusing the application for lack of inventive step, since the claims contained at least one feature that was not notoriously well known. Since a prior-art search was deemed necessary and its outcome could not be anticipated in advance, the assessment of the claimed subject-matter with respect to inventive step (and the other requirements of the EPC) had to be carried out anew. This constituted, in essence, a fresh case going beyond the issues discussed in the decision under appeal.

In T 1877/19, amendments to the application documents meant that the subject-matter claimed was no longer based entirely on a combination of claims as originally filed. In view of this, the examining division's search might not have included one of the claimed features, so the board could not be sure that the relevant prior art had been identified for it.

In T 1928/14 no written prior art had been consulted during the first-instance proceedings. The board was not sure whether the publications cited as A documents in the international search report covered the aspects of the additional features of claim 1 according to the request in hand. The supplementary European search report merely contained a "no-search declaration".

See also T 1338/16 (the board was not in a position to decide whether the scope of the search carried out by the department of first instance had also covered the subject-matter of claim 1 according to auxiliary request 5); T 568/17 (the question arose as to whether the search was complete; this was a question that the board was not equipped to answer); T 1278/18 (the board stated that since the added feature had been taken from the description and drawings, an additional search for relevant prior art might be necessary); T 2573/17 (the claims had been amended considerably during the proceedings at first instance and the board had doubts as to whether the search was complete).