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

1st line
pharmacotherapy
Response, no sideeffects
No
response or
side-effects
decision tree with a time horizon of 1 year, and
was conducted from the perspective of the UK
NHS. A ‘no treatment’ arm was not included on
the basis of the previous NICE guidance. 134
Model structure
In the model, patients begin therapy on BT, IR-
MPH, Concerta XL, ATX or Equasym XL. If they
responded to this first-line therapy and
experienced no side-effects, then they were
assumed to continue on the same treatment for
the rest of the year. If patients failed to respond to
first-line treatment, or experienced intolerable
side-effects within 1 month, they could then switch
to second-line treatment with BT (where BT was
not the first-line therapy), combination treatment
(BT plus the first-line pharmacotherapy) or other
drug treatment. The BT components were not
defined explicitly in the model, but as the
effectiveness data are sourced from the MTA
trial 133 we may assume that they correspond to
that trial protocol. The other drug treatment was
assumed to be DEX for patients receiving first-line
pharmacotherapy and IR-MPH for patients
receiving first-line BT. Patients responding to
second-line treatment remained on that therapy
© Queen’s Printer and Controller of HMSO 2006. All rights reserved.
BT
Combination
treatment
2nd-line
pharmacotherapy
FIGURE 21 Flow-chart of the cost–utility model submitted by Janssen-Cilag
Health Technology Assessment 2006; Vol. 10: No. 23
Response
No
response
Response
No
response
Response
No
response
Continue
Continue
No treatment
Continue
No treatment
Continue
No treatment
for the remainder of the year, and patients not
responding within 1 month of beginning secondline
therapy were assumed to discontinue all
treatment. Figure 21 presents a flow-chart of the
model. Owing to the 1-year time horizon,
discounting was not necessary.
Summary of effectiveness data
The measure of clinical effectiveness used in the
model was response rate to treatment. For the
comparison of Concerta XL with IR-MPH, the
effectiveness evidence was taken from the CON-
CAN-1 study. 90 The definition of a response was
taken from Swanson and colleagues 133 as a mean
score of ≤1 on the parent-rated SNAP-IV scale.
The same definition of response was used to
extract effectiveness data for BT from the BT-only
arm of the MTA trial. For the comparison of
Concerta XL with ATX, the effectiveness evidence
was taken from the FOCUS study. 99
[Confidential information removed].
The model also allowed patients to discontinue
therapy owing to inefficacy or adverse events
within 1 month. The data on discontinuation rates
87