An assembly for a drug delivery device, comprising: - a housing, - at least one stop feature, - at least one blocking member, - a piston rod configured to be axially displaced with respect to the housing for delivering a dose of a drug, wherein the at least one blocking member is part of the piston rod, - a rotation member, wherein the stop feature is part of the rotation member and wherein the rotation member is configured to rotate in a dose setting direction with respect to the housing for setting a dose of the drug and to rotate in a dose delivery direction with respect to the housing for delivering the set dose of the drug, and - a drive member which is adapted to follow rotational movement of the rotation member in the dose delivery direction with respect to the housing by mechanical interaction with the rotation member, wherein the drive member and the piston rod are rotationally locked with each other,wherein for setting the dose of the drug, the stop feature is configured to be rotated in the dose setting direction with respect to the blocking member and with respect to the housing and, for delivering the set dose of the drug, the blocking member is configured to be axially displaced, with respect to the stop feature away from an axial starting position and towards an axial interaction position, wherein, when the blocking member is in the axial starting position, the blocking member is axially offset from the stop feature and, when the blocking member is in the axial interaction position, the blocking member is configured to mechanically cooperate with the stop feature such that rotation of the stop feature in the dose setting direction with respect to the housing is prevented, the stop feature and the blocking member thereby providing an end-stop mechanism for the drug delivery device, characterized in that the assembly comprises a stop member which is adapted to prevent rotational movement of the drive member in the dose setting direction with respect to the housing by mechanical cooperation with the drive member when the rotation member is rotated in the dose setting direction with respect to the housing. - a housing, - at least one stop feature, - at least one blocking member, - a piston rod configured to be axially displaced with respect to the housing for delivering a dose of a drug, wherein the at least one blocking member is part of the piston rod, - a rotation member, wherein the stop feature is part of the rotation member and wherein the rotation member is configured to rotate in a dose setting direction with respect to the housing for setting a dose of the drug and to rotate in a dose delivery direction with respect to the housing for delivering the set dose of the drug, and - a drive member which is adapted to follow rotational movement of the rotation member in the dose delivery direction with respect to the housing by mechanical interaction with the rotation member, wherein the drive member and the piston rod are rotationally locked with each other,wherein for setting the dose of the drug, the stop feature is configured to be rotated in the dose setting direction with respect to the blocking member and with respect to the housing and, for delivering the set dose of the drug, the blocking member is configured to be axially displaced, with respect to the stop feature away from an axial starting position and towards an axial interaction position, wherein,