An open-label, cross-over, multi-site, prospective, phase IIb study of effects on circadian rhythms and quality of life of modifieddual-release hydrocortisone Efmody™ versus immediate-release hydrocortisone in patients with Addison’s Disease

1. To measure the change from baseline in QoL using the Health-related Quality of Life in Addison's disease (AddiQoL) questionnaire, after 11 weeks treatment with Efmody™ compared with immediate-release hydrocortisone [ Time Frame: Baseline and end of each 11 week treatment period. (see protocol section 10.3.1 for further details)