Participants in eligible countries completing one of the specified previous Chronocort studies (DIUR-006 and DIUR 014) can either continue Chronocort treatment (if the participant received Chronocort in the feeder study) or switch to Chronocort treatment (if the participant received standard glucocorticoid therapy in the feeder study) in this open-label extension study. All participants choosing to enter this extension study will have the study procedures fully explained and informed consent obtained, prior to, or at the last visit of the feeder study. Participants who agree to take part in this extension study will then undergo the final visit of the feeder study, with the assessments conducted at the final visit also providing the baseline data for this DIUR-015 extension study where relevant (note participants who are withdrawn from treatment due to titration issues in study DIUR-014 are eligible to enter at the discretion of the Investigator, as long as all DIUR-014 safety assessments and the end of study visit are completed). Once all the baseline assessments are completed, participants will be given sufficient Chronocort to use until the next visit (the study pharmacies will be supplied with Chronocort for dispensing to participants according to the Investigators' instructions).~Outcome measures in this study will be assessed versus either the 'initial study baseline' (measurements taken at the start of participation in an interventional Diurnal study, regardless of the treatment assignment in this feeder study) or the protocol-defined 'pre-Chronocort baseline' (measurements taken prior to the first dose of continuous Chronocort).
This phase III study is an open-label extension study to be conducted at approximately 36 investigational sites across 3 countries. The study will evaluate the long-term safety and tolerability of Chronocort in participants aged 16 years and over when used as treatment for Congenital Adrenal Hyperplasia (CAH).