Extension Treatment Using EryDex System in Patients With AT Who Participated in the ATTeST-IEDAT-02-2015 Study

Primary Objective To monitor and evaluate the long-term safety and tolerability of EDS-EP in AT patients. Secondary Objective To evaluate the long-term effect of EDS-EP on health-related Quality of Life (QoL; EQ-5D-5L scale). Exploratory Objective: To evaluate the long-term effect of EDS-EP in treating central nervous system (CNS) symptoms, as measured by the "Modified" International Cooperative Ataxia Rating Scale (mICARS), and Clinical Global Impression of severity and change (CGI-S/C).