If the international preliminary examination report has been drawn up by the EPO, it is to be regarded as an opinion for purposes of examination, and generally the first communication will be based on the opinion expressed in the IPER and the applicant's response to it filed in accordance with Rule 161(1) (if applicable, see E‑IX, 3). Such an opinion may be departed from if new facts relevant to assessing patentability are in evidence (e.g. if further prior-art documents are to be cited or if evidence is produced of unexpected effects), where the substantive patentability requirements under the PCT and the EPC are different, where applicants provide convincing arguments, appropriate amendments or relevant counter-evidence in their response to the IPER according to Rule 161(1), or conversely where the applicant provides amendments in response to the IPER which introduce further deficiencies.[Rule 161(1); Rule 159; ]

Examination reports drawn up by other International Preliminary Examining Authorities must be examined carefully. If the reasons put forward in the international preliminary examination report are sound, they must not be disregarded.