A drug delivery device includes a housing defining a shell and an inner volume, a cassette, a door coupled to the housing, a drive mechanism, and a latching assembly. The cassette is removably disposed within the inner volume and is adapted to contain a drug to be administered to a user. The door at least partially encloses the inner volume of the housing and includes a first end defining a latching portion. The drive mechanism is at least partially disposed within the housing and exerts a force to urge the drug out the cassette. The latching assembly is coupled to the drive mechanism and includes a first end and a second end. Upon actuating the drive mechanism, the drive mechanism causes the latching assembly to engage the latching portion of the door to secure the door to the housing.