A drug delivery device comprising: a housing (12) having an opening; an adhesive disposed on an exterior surface of the housing for attaching the drug delivery device to a patient; at least one of a needle and a cannula initially disposed within the housing; an insertion mechanism (200) disposed within the housing and including at least one biasing member configured to drive the at least one of the needle and the cannula through the opening into the patient: a fluid pathway connection (300) disposed within the housing and comprising: a drug container (50) including a barrel (58) having a proximal end and a distal end, and a pierceable seal (56) disposed at the proximal end of the barrel: a piercing member (330): a fluid conduit (30) configured to provide fluid communication between the piercing member and the at least one of the needle and the cannula; a connection hub (310), the piercing member being connected to the connection hub: and a sterile sleeve (320) having an interior space and being fixedly coupled to the proximal end of the barrel of the drug container, the piercing member being disposed between the connection hub and the pierceable seal of the drug container in an initial unactivated position, wherein the pierceable seal and the connection hub are adapted for relative movement between the initial unactivated position wherein the piercing member does not pierce the pierceable seal, and an activated position wherein the piercing member extends through the pierceable seal, the piercing member moving through the interior space of the sterile sleeve during movement from the initial unactivated position to the activated position.
