Liquid drug transfer devices for use with an injection vial and including a vial adapter having a puncturing cannula for puncturing a vial stopper and a fluid transfer port in flow communication with the puncturing cannula. The vial adapter includes set up vial retention flex members for vial retention purposes in a set up position without puncturing an injection vial and activation vial retention flex members for vial retention purposes in an activation position puncturing the injection vial.