An applicant may withdraw an international patent application, e.g., to prevent international publication. The notice withdrawing an international application must be received by the International Bureau or the Receiving Office before the expiration of 20 months from the priority date or 20 months from the PCT filing date, whichever is earlier. If a Demand for international preliminary examination has been timely filed, the notice must be received before the expiration of 30 months from the priority date or 30 months from the PCT filing date, whichever is earlier.
Law - Withdrawal of PCT Application