A Study of the Efficacy, Safety and Tolerability of Chronocort in Treating CAH

All subjects will have a screening visit prior to the baseline assessment to allow DIUR-006
procedures to be fully explained and informed consent to be given by the subject. For
subjects from DIUR-003 this screening visit will include safety blood tests. Any subjects not
meeting the inclusion/exclusion criteria following these blood tests will be not be entered
into the study.

All subjects will then return for the baseline visit. For subjects entering from study
DIUR-003 the full set of baseline assessments will be completed, including 2 blood samples
(one at 09:00 and one at 13:00 hours) for 17-OHP and A4. For subjects entering from DIUR-005,
test results from their last visit in the feeder study (Visit 4) will be used for this
baseline assessment, with the 09:00 and 13:00 hour results taken from the 24-hour hormone
profiles conducted at the visit. Any subjects not meeting the inclusion/exclusion criteria
following these blood tests will be withdrawn from this study.

Once the baseline assessments are completed, the subjects will be given sufficient
Chronocort® to use until the next visit at Week 4. Subjects from study DIUR-005 who were
previously on Chronocort® will continue on the same dose of Chronocort® that they were
receiving at the end of the feeder study. Subjects from study DIUR-005 on standard therapy
and subjects from study DIUR-003 will have their initial dose of Chronocort® determined using
the hydrocortisone equivalent of baseline therapy.

All subjects will return to the study centre at 4, 12 and 24 weeks after starting study
DIUR-006 for additional blood tests and dose titration, if necessary. Visits thereafter will
take place at 6-monthly intervals. If there is a change of dose, an interim visit will be
needed inbetween the 6-monthly visits.

All subjects will receive telephone calls at 3 monthly intervals, and unscheduled visits will
be arranged if necessary. Subjects will also be provided with Chronocort® supplies from the
study pharmacy at 3-monthly intervals.

Inclusion Criteria:

1. Subjects with CAH who have successfully completed a clinical trial with the current
formulation of Chronocort®.

2. Provision of signed written informed consent.

Exclusion Criteria:

1. Co-morbid condition requiring daily administration of a medication (or use of any
medications/supplements) 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 ULN]).

3. Females who are pregnant or lactating.

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

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

6. Subjects with a history of bilateral adrenalectomy.

7. Participation in another clinical trial of an investigational or licensed drug or
device within the 3 months prior to inclusion in this study, except for another
clinical trial with the current formulation of Chronocort®.

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

9. Subjects who routinely work night shifts and so do not sleep during the usual
nighttime hours.