Biochemical response was defined as a participant who a) was in biochemical control at the 08:00 assessment and b) was receiving a total daily dose of hydrocortisone of not more than 25 mg if the participant was in biochemical control at baseline or not more than 30 mg if the participant was not in biochemical control at baseline. Biochemical control was defined as both a 17-OHP concentration equal to or below the upper limit for optimal control (1200 ng/dL \[36.4 nmol/L\]) and an A4 concentration equal to or below the upper limit of the reference range (150 ng/dL \[5.2 nmol/L\] for men and 200 ng/dL \[7.0 nmol/L\] for women). Assessment of efficacy at Week 28 was a composite of each participant's on-treatment visit closest in time to 28 weeks post randomization.

Over-replacement normally presents with chronic effects such as weight gain, increased appetite, sleeping difficulties, increased acne and Cushingoid syndrome.

Under-replacement normally presents with acute effects such as sudden weight loss, lack of appetite, nausea, vomiting, headache, blurred vision, fatigue, weakness, dizziness, light-headedness and syncope.

Use of Immediate Release Hydrocortisone (IRHC) from the emergency packs for stress dosing or use of any additional glucocorticoid treatment.

Occurrence of adrenal crises throughout the study.

The incidence, nature, severity, relatedness, duration, outcome, seriousness, and expectedness of treatment-emergent adverse events (TEAEs) throughout the study.

Lab parameters will be summarized and compared throughout the study as follows: Platelet count, Red blood cell count (RBC), Haemoglobin, Haematocrit, RBC Indices: Mean corpuscular volume (MCV), Mean cell haemoglobin (MCH). Mean cell haemoglobin concentration (MCHC), Red cell distribution width (RDW). White blood cell (WBC) count with differential (absolute and %): Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils.

To measure the change from pre-Chronocort baseline in terms of clinical chemistry safety laboratory assessments \[Safety and Tolerability\]. Blood urea nitrogen (BUN), Creatinine, Chloride, Total magnesium, Potassium, Sodium, Calcium, Total carbon dioxide (CO2), Inorganic phosphorus, AST/serum glutamic-oxaloacetic transaminase (SGOT), ALT/serum glutamic-pyruvic transaminase (SGPT), Alkaline phosphatase, Albumin, Total and direct bilirubin, Total protein, Lactate dehydrogenase (LDH), Total creatine kinase (CK), Uric acid.

Blood pressure measurements throughout the study will be summarised and compared.

Change from baseline to 24 weeks of the mean of the 24-hour standard deviation score (SDS) - also referred to as a z-score - profile for 17-OHP (17-Hydroxyprogesterone). The primary efficacy variable was the natural logarithm of the mean of the 24-hour SDS for the natural logarithm of 17-OHP. The mean of the 24-hour SDS profile for each visit was the arithmetic mean of all the SDSs with the first and last (13th) weighted one half relative to the intermediate SDSs. For each of the 13 log-transformed 17-OHP values at each visit, an SDS was calculated by counting the number of SDs that were above or below the mean of the log-transformed range. A negative z-score indicated greater control of 17-OHP when compared to baseline (0).

Tmax measures the time at which Cmax - maximum serum concentration - is observed

Tlag measures the delay between dosing and being able to observe the drug/metabolite within the sampling area (e.g., blood serum)

Cmax measures the time taken for the drug/metabolite to reach maximum serum concentration

Area under the serum concentration versus time curve from time

Area under the serum concentration versus time curve from time = 0h extrapolated to infinity

Time to drug clearance

Time required to reach 1/2 Cmax