A systematic review of the effectiveness of adalimumab

90
Health economics
combination of ciclosporin with methotrexate
would still be available in this case. When the
model is run, initial characteristics for (virtual)
patients are sampled from the starting distribution.
Each patient is then run independently through
each of the six options and differences in costs
and QALYs between options are recorded. This
process is repeated for a sufficiently large number
of patients to produce a statistically stable
comparison between each pair of options.
Single TNF inhibitor as third line therapy In this
strategy set, TNF inhibitors are considered as
third line therapy; that is, after two DMARDs
including methotrexate have been tried, in
accordance with current NICE guidance.
Each (virtual) patient is started on methotrexate.
Patients who quit methotrexate on grounds of
toxicity move to single-therapy sulfasalazine.
Those who quit for any other reason move to the
combination of methotrexate plus sulfasalazine.
Any patient who dies while still on one of the
treatments mentioned so far is discarded from the
TABLE 36 Strategy set with TNF inhibitors in third place
analysis and replaced by a new (virtual) patient
starting again from the beginning with
methotrexate. Any patient who fails on
sulfasalazine (or methotrexate plus sulfasalazine)
has reached the divergence point between the
options (see Table 36; options after the divergence
point are shaded). The patient’s characteristics at
this moment are stored for future use, and the
patient is run through the rest of option 1,
continuing with adalimumab and then
leflunomide, and so on.
Costs and QALYs are counted only from the
divergence point, and are discounted to
the divergence point. The patient characteristics
at the divergence point are retrieved, and the
patient is run through option 2, starting with
etanercept followed by leflunomide. Once the
costs and QALYs for option 2 have been
calculated, the patient characteristics at the
divergence point are again retrieved, and the
patient is run through option 3, starting this time
with the combination adalimumab plus
methotrexate, except that if methotrexate has
Moves dependent on toxicity
Treatment Always move to Relevant toxicity If toxic, move to Otherwise, move to
MTX MTX SSZ MTX+SSZ
SSZ Divergence point
MTX+SSZ Divergence point
Option 1 Adal
Adal LEF
Option 2 Etan
Etan LEF
Option 3 MTX Adal Adal+MTX
Adal+MTX LEF
Option 4 MTX Etan Etan+MTX
Etan+MTX LEF
Option 5 Infl+MTXa Infl+MTX LEF
Option 6 LEF
LEF GST
GST AZA
AZA CyA
CyA CyA or MTX DPen CyA+MTX
CyA+MTX DPen
DPen Pall
a The data set for this combination is used in the model, regardless of the reason for quitting MTX.