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

70
Economic model
TABLE 46 Analysis 2 – estimates of mean lifetime costs and QALYs for the full range of potential comparators, including adjustment
for adverse events
Intervention Cost (£) LYG QALY ICER (£) Probability cost-effective (%)
utility estimate applied in the main analysis
(0.538).
Tables 48 and 49 report the results for Analyses 1
and 2 using the combined utility values derived
from an alternative classification system based on
FACT-P. The application of a higher utility
estimate resulted in a more favourable ICER for
docetaxel. The ICER of D + P (3-weekly) in
Analysis 1 was £28,019 per QALY, compared with
M + P. In Analysis 2, D + E was no longer ruled
out by extended dominance. Hence the ICER of
D + P (3-weekly) in Analysis 2 was calculated in
comparison with D + E. The ICER for this
comparison was £29,436 per QALY.
Value of information
A non-parametric approach was used to determine
the costs of uncertainty associated with the
adoption decision. 87 The use of Monte Carlo
simulation allows the error probability associated
with the adoption decision to be expressed as the
proportion of iterations which result in an
adoption decision other than that selected on the
basis of expected cost-effectiveness. The benefit
forgone is simply the difference in the costs and
outcomes (net benefit) between the optimal
strategy for a given iteration and those of the
strategy identified as optimal on the basis of
expected cost-effectiveness estimates. The
expectation of benefits forgone over all iterations
represents the expected value of perfect
information (EVPI) per individual.
Clearly, since information can be of value to more
than one individual, EVPI can also be expressed for
the total population who stand to benefit over the
expected lifetime of the programme/technology. 88,89
If the EVPI for the population of current and
future patients exceeds the expected costs of
additional research, then it is potentially costeffective
to conduct further research. The overall
value of information for a population is
determined by applying the individual EVPI
estimate to the number of people that would be
affected by the information over the anticipated
lifetime of the technology:
T
It EVPI* ∑ –––––––
t = 1(1 + r) t
£20,000 £30,000 £40,000
M + P + C 10,962 1.47 0.77734 Dominated 25 16 12
P 11,242 1.51 0.80103 Dominated 29 22 17
M + P 10,801 1.51 0.79917 – 19 13 8
D + P (weekly) 26,263 1.57 0.83042 Dominated 0 0 0
D + E + P (70) 16,302 1.61 0.85455 Dominated 7 12 16
D + E + P (35) 18,437 1.67 0.90008 Dominated 1 3 4
D + E 14,967 1.74 0.92071 Extended dominated 12 20 24
D + P (3-weekly) 15,859 1.80 0.95107 33,298 7 14 20
TABLE 47 Alternative health state utility values based on
scenarios developed using FACT-P
Advanced disease state Mean SE
FACT-P (early) 0.725 0.0393
FACT-P (moderate) 0.6159 0.0501
FACT-P (late) 0.5774 0.0476
Combined estimate 0.638 0.0462
where I = incidence in period, t = period,
T = total number of periods for which
information from research would be useful, and
r = discount rate.
No details regarding the prevalence and/or
incidence of HRPC were identified for the UK in
any of the articles considered by the clinical
effectiveness and cost-effectiveness reviews. In the
absence of these data, we used national mortality
statistics for all patients with prostate cancer in
England and Wales (9161) 2 and an assumption
that only 30% of these patients would require and
be eligible for docetaxel plus
prednisone/prednisolone. This gives an annual
population of 2748 patients for whom this
decision is relevant. In addition, the time horizon