Docetaxel with prednisone or prednisolone for the treatment of ...

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Economic model
TABLE 36 Follow-up costs for docetaxel regimens
Docetaxel regimen Mean (£) SE (£) Distribution
Terminal care cost 3527.95 1763.98 Gamma 4.00 881.99
6–10 months 1551.29 775.65 Gamma 4.00 387.82
10–14 months 718.40 359.20 Gamma 4.00 179.60
14–18 months 1461.49 730.75 Gamma 4.00 365.37
18–22 months 7616.34 3808.17 Gamma 4.00 1904.09
22–26 months 6674.97 3337.49 Gamma 4.00 1668.74
>26 months 4827.96 2413.98 Gamma 4.00 1206.99
TABLE 37 Follow-up costs for mitoxantrone regimens
Mitoxantrone regimen Mean (£) SE (£) Distribution
Terminal care cost 3,942.16 1,971.08 Gamma 4.00 985.54
6–10 months 3,080.91 1,540.46 Gamma 4.00 770.23
10–14 months 1,753.84 876.92 Gamma 4.00 438.46
14–18 months 4,779.66 2,389.83 Gamma 4.00 1,194.92
18–22 months 3,286.83 1,643.42 Gamma 4.00 821.71
22–26 months 8,079.19 4,039.60 Gamma 4.00 2,019.80
>26 months 12,679.52 6,339.76 Gamma 4.00 3,169.88
we assigned a one-off cost to the transition to the
dead state. In the absence of data on these
additional costs we estimated them from those
patients who died within the first 6 months, as
reported by Sanofi-Aventis. This terminal care
component was then subtracted from the total
follow-up costs associated with each of the other
periods. In the absence of specific patient-level
information detailing costs per monthly cycle, all
follow-up costs were assigned as patients died
(cycle). For the purposes of discounting, terminal
care costs were discounted at the rate for the
appropriate cycle and other follow-up costs were
discounted based on the mid-point of the followup
period reported.
Additional information was requested to quantify
the sample uncertainty in these estimates;
however, this information could not be provided.
In the absence of these data, we made the
assumption that the standard error was equal to
half of the mean value (i.e. the coefficient of
variation was 0.5) as suggested by Briggs and
colleagues. 70 A gamma distribution was assigned
to each follow-up period using the methods of
moments approach. 70
In the absence of specific patient-level information
detailing costs for each of the treatments
considered in analysis 2, we made the following
assumptions. The follow-up costs for docetaxel
plus prednisone/prednisolone 3-weekly [D + P
(3-weekly)] were used as the basis for the follow-up
costs for all regimens incorporating docetaxel.
Hence the only differences assumed in the costs
modelled for these treatments were those due to
differences in acquisition costs and in overall
survival. A similar approach was used to model the
costs of M + P + C based upon the follow-up costs
reported for mitoxantrone and prednisone.
Tables 36 and 37 report the follow-up costs applied
to the models and the parameters of the
associated gamma distributions.
No data were provided within the company
submission regarding the potential follow-up costs
associated with non-chemotherapy regimens (i.e.
prednisone/prednisolone alone). However, as
detailed previously in the review of published costeffectiveness
analyses, Bloomfield and colleagues 64
reported the results of the costs and outcomes for a
comparison of M + P versus P. This study was used
to estimate the costs of P on the basis of an
adjustment to the costs of M + P. We requested
additional patient-level data from one of the
authors of the Bloomfield study (Willan A,
Department of Public Health Sciences, University
of Toronto; personal communication, 2005). On the
basis of the data provided, an adjustment was made
based on the relative differences in the follow-up
costs between M + P and P. Costs were converted
from Canadian dollars to pounds sterling using the
appropriate exchange rate based on the price year
used in the Bloomfield study. Gamma distributions