Comparison of Chronocort Versus Standard Hydrocortisone Replacement Therapy in Participants Aged 16 Years and Over With Congenital Adrenal Hyperplasia

Clinical or biochemical evidence of hepatic or renal disease e.g. creatinine \>2 times the upper limit of normal (ULN) or elevated liver function tests (alanine aminotransferase \[ALT\] or aspartate aminotransferase \[AST\] \>2 times the ULN).

History of bilateral adrenalectomy.

History of malignancy (other than basal cell carcinoma successfully treated \>26 weeks prior to entry into the study).

Participants who have type 1 diabetes or receive regular insulin, have uncontrolled diabetes, or have a screening HbA1c greater than 8%.

Persistent signs of adrenal insufficiency or the participant does not tolerate treatment at the end of the 4-week run-in period.

Participants with any other significant medical or psychiatric conditions that in the opinion of the Investigator would preclude participation in the study.

Participants on regular daily inhaled, topical, nasal or oral steroids for any indication other than CAH.

Co-morbid condition requiring daily administration of a medication or consumption of any material that interferes with the metabolism of glucocorticoids.

Participants who are receiving \<10 mg hydrocortisone dose at screening or the hydrocortisone dose equivalent.

Participants anticipating regular prophylactic use of additional steroids e.g. for strenuous exercise.

Participation in another clinical study of an investigational or licensed drug or device within the 12 weeks prior to screening.

Inclusion in any natural history or translational research study that would require evaluation of androgen levels during the study period outside of this protocol's assessments.

Participants who have previously been exposed to Chronocort in any Diurnal study.

Participants who routinely work night shifts and so do not sleep during the usual night-time hours.

Participants, who in the opinion of the Investigator, will be unable to comply with the requirements of the protocol.

Participants with a known hypersensitivity to any of the components of the Chronocort capsules, the Cortef tablets, or the placebo capsules.

Participants with congenital galactosemia, malabsorption of glucose and galactose, or who are lactase deficient.

Participants with a body weight of 45 kg or less.

What this study is about