Provided herein is a fluid pathway connection assembly, e.g., for connecting a fluid flowpath within a drug delivery device for delivery of a medicament to a target site. The fluid pathway connection assembly comprises a hollow needle piercing member, a sleeve fixedly engaged with the piercing member and a pierceable seal configured to sealingly engage the piercing member or the sleeve. Upon, sealing engagement, the piercing member or the sleeve and the pierceable seal form a volume within which a portion of the piercing member is disposed. The fluid pathway connection assembly is activated by relative movement between the piercing member and the pierceable seal and activation causes the piercing member to pierce the pierceable seal, thereby establishing a fluid flowpath through the pierceable seal. Upon incorporation of the assembly into a sealed fluid flowpath, the volume is isolated from the environment and maintains the sterile condition of the portion of the piercing member disposed therein. Also provided herein are drug delivery pumps and methods of operating and assembling the assemblies and pumps described herein.