A drug delivery system for injecting a medicament includes a container including a closure and a stopper configured to move within the container from a pre-use position to a post-use position. The system includes a drive assembly configured to move the stopper between first and second positions, and a spacer assembly engaged with the stopper configured to be engaged by the drive assembly. The spacer assembly includes a first spacer portion received within the stopper, a second spacer portion spaced from the first spacer portion, an inner plunger, and a spacer shuttle received by the inner plunger. The inner plunger, the spacer shuttle, and the second portion are configured to move relative to the stopper, where movement of the second spacer portion is restricted by the spacer shuttle, movement of the spacer shuttle is restricted by the inner plunger, and movement of the inner plunger is restricted by the stopper.
