Drug delivery devices and related methods of assembly are disclosed. The drug delivery device may include a container including a wall with an interior surface and a seal member with an end surface. The interior surface of the wall and the end surface of the seal member may define a reservoir filled with a drug. A fluid pathway assembly may be connected to the container and include an overmold member that covers a length of a container access needle and which defines an enclosed space with the seal member. The overmold member may be moveable relative to the seal member to carry the container access needle between a storage position, where a point of the container access needle is disposed exterior to the reservoir, and a delivery position, where the point extends through the end surface of the seal member into the reservoir.