Systems for piercing a septum of a drug delivery device is disclosed. The drug delivery device may include a needle conduit having an end and a drug container having a septum. The septum piercing mechanism may include a needle support operatively coupled to the needle conduit. The septum piercing mechanism may be movable from a first, unactivated configuration to a second, activated configuration. In the unactivated configuration, the septum seals an interior of the drug container from the end of the needle conduit. In the activated configuration, the end of the needle conduit pierces through the septum placing the needle conduit in fluid communication with the drug container. In one embodiment, activation may cause the needle support to move towards the drug container. In one embodiment, the needle support may be moved by a biasing member. Alternatively, in another embodiment, the needle support may be moved by a cam mechanism.