['congenital adrenal hyperplasia']
['chronocort®', 'standard glucocorticoid therapy']

        Inclusion Criteria:

          1. Known CAH due to 21-hydroxylase deficiency (classic CAH) diagnosed in childhood with
             documented (at any time) elevated 17-OHP and/or A4 and currently treated with
             hydrocortisone, prednisone, prednisolone or dexamethasone (or a combination of the
             aforementioned glucocorticoids) on a stable glucocorticoid therapy for a minimum of 6
             months.

          2. Provision of signed written informed consent.

          3. Non-pregnant, non-lactating females who are post menopausal, naturally or surgically
             sterile, or of childbearing potential with a negative urinary pregnancy test and using
             a medically acceptable method of contraception.

          4. Plasma renin activity (PRA) less than 1.5 times the upper limit of normal (ULN) at
             screening or within 3 months prior to screening, except in subjects who have been
             diagnosed with hypertension where the renin is not being used to monitor
             fludrocortisone replacement.

          5. Plasma renin activity (PRA) less than 1.5 times the upper limit of normal (ULN) at
             screening or within 3 months prior to screening, except in subjects who have been
             diagnosed with hypertension where the renin is not being used to monitor
             fludrocortisone replacement.

        Exclusion Criteria:

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

          2. Clinical or biochemical evidence of hepatic or renal disease. Creatinine over twice
             the ULN or elevated liver function tests (ALT or AST >2 times the ULN).

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

          4. Subjects with any other significant medical or psychiatric conditions that in the
             opinion of the investigator would preclude participation in the trial.

          5. History of malignancy (other than basal cell carcinoma successfully treated >6 months
             prior to entry into the study).

          6. Participation in another clinical trial of an investigational or licensed drug or
             device within the 3 months prior to inclusion in this study.

          7. Subjects with a history of bilateral adrenalectomy.

          8. Subjects having previously been exposed to Chronocort®.

          9. Subjects unable to comply with the requirements of the protocol.
      