A drug delivery device (1) is proposed, comprising: a housing (10, 350)； a drive mechanism (5)； a cartridge (301) containing a drug (307), the cartridge being retained in a defined position relative to the housing, wherein the drive mechanism is configured to dispense drug from the cartridge； a cartridge bias system (400), which comprises at least one resilient member (402, 403) and at least one rigid force transfer body (401), wherein the rigid force transfer body is movably retained in the housing, wherein the cartridge bias system is arranged and configured to exert a force on the cartridge to maintain the cartridge in the defined position, wherein the force is provided by the at least one resilient member, and wherein the rigid force transfer body is operatively connected to the at least one resilient member such that the force is reacted by the rigid force transfer body. Further, a method to modify a drug delivery device is disclosed.
