Defense of patent only in appeal is late-filed

If a patent proprietor chooses not to file any submissions during the opposition proceedings but to present them only with its statement of grounds of appeal, this amounts to bringing an entirely fresh case in appeal proceedings. This is at odds with the primary object of the appeal proceedings to review the decision under appeal in a judicial manner. Consequently, a board has the discretion under Art 12 (4) RPBA 2007 not to admit the patent proprietor's defense submissions into the appeal proceedings. This does, however, not necessarily lead to revocation of the patent. The decision under appeal is still to be reviewed by the Board of Appeal, which might overturn the impugned decision, for example if it is not convinced by the reasons given by the opposition division or in the event of a substantial procedural violation (EPO Board of Appeal 2/02/2022, T 2120/18).