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

TABLE 24 Other in-trial costs
a body surface area of 1.7 m 2 may underestimate
the total costs for both docetaxel and
mitoxantrone for this population, depending on
whether an additional vial (or larger vial size) is
required to administer the required dosage for this
higher body surface area. The potential
implications of this are addressed in the section
‘Comments’ (p. 50).
Administration costs were reported to be £117 per
cycle. No supporting reference was provided to
the source of this unit cost. After consultation with
Sanofi-Aventis the figure was stated to be based on
the ISDScotland cost book, which classifies
oncology speciality treatment as radiotherapy.
Hence it has been assumed that the cost of
chemotherapy administration is costed as a
radiotherapy outpatient visit, which is listed as
£117 (based on 2002–3 prices).
The number of cycles of chemotherapy applied in
this analysis was based on the mean number of
cycles derived from TAX 327. Although from an
economic perspective it can be argued that the
mean is the most appropriate measure of central
tendency from a decision-maker’s perspective, a
comparison of these estimates with the median
number of cycles suggests that the distribution of
chemotherapy cycles is highly skewed. The median
numbers of cycles (range) reported in TAX 327
were 9.5 (1–11) for the docetaxel 3-weekly
regimen and 5 (1–11) for mitoxantrone. Hence
the analysis based on mean number of cycles (7.3
versus 5.9) will result in lower average costs for the
docetaxel regimen and higher costs for
mitoxantrone in comparison with an analysis
based on median number of cycles. In these
instances, while the mean may be considered the
most appropriate point estimate, it is important to
demonstrate the robustness of the results to
alternative assumptions due to the relatively high
Health Technology Assessment 2007; Vol. 11: No. 2
Item Docetaxel (£) Mitoxantrone (£) Difference a (docetaxel – mitoxantrone) (£)
Blood 14 12 3
Bisphosphonates 317 264 53
Epoetin 84 27 59
G-CSF 96 12 84
Hormone therapy 1661 1265 396
Chemotherapy 2710 3381 –671
Hospitalisations 2555 3056 –501
Total 7438 8016 –579
G-CSF, granulocyte colony-stimulating factor
a Rounded to 2 decimal places
© Queen’s Printer and Controller of HMSO 2007. All rights reserved.
uncertainty surrounding these point estimates.
This issue is discussed further in the section
‘Comments’ (p. 50).
Table 24 summarises the other in-trial costs,
including the costs of managing side-effects
during first-line chemotherapy phase and costs
incurred during follow-up phase. Mean total costs
were approximately £579 lower in the docetaxel
group compared with patients randomised to
receive mitoxantrone. Much of this difference was
attributed to a reduction in the cost of subsequent
chemotherapy and lower hospitalisation costs.
The mean total costs of first-line chemotherapy
and follow-up costs are summarised in Table 25.
Total costs were approximately £6056 higher for
patients randomised to receive docetaxel
compared with mitoxantrone. The majority of this
difference was attributed to the higher drug
acquisition costs of docetaxel. Although
subsequent follow-up costs were lower in this
group, these differences were more than offset by
these higher initial costs.
Although formal survival analytic approaches have
been applied to account for censoring in the
survival data, it is unclear how censoring in the
cost data has been accounted for in these analyses.
The total costs presented in the report are
described as “generating an average lifetime cost
per patient” (Ref. 61, p. 53). 61,66–68 However, no
details were provided in order to ascertain the
validity of the approach used to handle censoring
in the cost data.
A separate sensitivity analysis was, however,
undertaken using the method proposed by Lin
and colleagues, for estimating average costs in the
presence of censoring. 69 The method of Lin and
colleagues requires the period of interest to be
49