A systematic review and economic model of the effectiveness and ...

The review also uncovered a mis-reference in
calculating the costs of behavioural therapy.
Correcting this error did not change the results as
behavioural therapy was consistently dominated. We
re-analysed the model by Janssen-Cilag, correcting
for each of the detailed errors in turn. The results
of these re-analyses are shown in Table 75.
Review of the Celltech submission
Overview
The aim of the Celltech submission was to
compare Equasym XL (ER-MPH8) with no
treatment in patients unable to comply with twicedaily
IR-MPH, using new evidence made available
since the previous NICE guidance was issued. 134
The submission therefore concentrates on data
concerning the effectiveness of Equasym XL,
which was not included in the previous review. A
secondary analysis also compared Equasym XL
with no treatment and twice-daily IR-MPH.
A partially probabilistic cost–utility analysis was
conducted based primarily on reviews of treatment
for ADHD. The model took the form of a decision
tree with a time horizon of 1 year, and was
conducted from the perspective of the UK NHS.
Concerta XL (ER-MPH12) and ATX were not
included as comparators.
Model structure
Patients enter the model on MPH, in the form of
Equasym XL, in the base case. IR-MPH is added as
a second comparator in the secondary analysis.
After a 42-day titration period, patients may comply
or not with treatment. Non-compliers are assumed
to continue on treatment, but experience no health
benefits. Among those complying with treatment,
the proportion that experience a response and no
intolerable side-effects are assumed to remain on
treatment for the rest of the year; the proportion
who do not respond, or who experience intolerable
side-effects, progress to second-line treatment with
DEX. Second-line therapy follows the same pattern
as first-line therapy, with a 42-day titration period,
compliers/non-compliers and discontinuations due
to inefficacy or adverse events. Those patients who
discontinue DEX may progress to BT or no
treatment. In the base case it is assumed that 50%
of these patients will progress to BT and experience
health benefits, whereas the remaining 50% will
progress to no treatment and receive no health
benefits. The BT was described as intensive
psychosocial treatment involving eight visits to
members of child/adolescent psychiatry or
psychology teams.
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Health Technology Assessment 2006; Vol. 10: No. 23
Patients progressing through the model were
compared with ‘no treatment’ in the base case,
which was assumed to incur no health costs or
health benefits. Owing to the 1-year time horizon,
discounting was not necessary.
Summary of effectiveness data
The model assumed that compliance with
morning doses of each drug would be 85% (95%
CI 50 to 100%) and compliance with lunchtime
doses of twice-daily drugs would be 55% (95% CI
40 to 85%). The uncertainty around these
estimates was characterised using a normal
distribution. These values were chosen to
correspond to reported figures of overall
compliance to IR-MPH of 65–75%. 41,138 Hence
compliance to Equasym is calculated to be 85%
and compliance to IR-MPH or DEX is, on
average, 70%.
The measure of effectiveness used in the model
was response rate to treatment. The model
assumes that response rates to IR-MPH, Equasym
XL and DEX will be equal, based on previously
published evidence that they are similar. 59,139 The
response rate is set at 70% (Scottish Intercollegiate
Guidelines Network, 2001). 4,123 A definition of
response is not provided. The model also assumed
that around 6% of patients beginning any of the
drug therapies would discontinue owing to
adverse events, 123 which gives a continuation rate
of 66% (70% of 94%). The uncertainty around this
estimate was characterised using a normal
distribution where the upper and lower bounds of
the 95% CI were assumed to be 60 and 82%,
respectively.
Summary of resource utilisation and
cost data
The unit costs of medication were based on
published pricing lists for the UK (BNF 47).
Equasym XL is not currently priced in the UK,
and so the submission includes costs specified by
the manufacturer. The prices used are shown in
Table 76.
During the titration period, it was assumed that
one-third of patients would be on the equivalent
of 5, 10 and 15 mg of IR-MPH twice daily,
respectively. The average dose after titration was
assumed to be 30 mg per day, based on previously
published data 123 and data from the IMS Health
Disease Analyser Mediplus dataset (reference not
provided in submission). Patients progressing to
DEX were assumed to receive 5 mg once daily at
the start of the titration period, and assumed to
reach an average of 10 mg per day subsequently,
93