Mortality after transplant in the
economic model
Mortality rates are higher after stem cell
transplant than in the general population
and should be included in the model.
In its base-case economic model, the
company applied general population
mortality rates when the modelled
mortality rates would otherwise have been
lower. In a scenario analysis, the company
increased mortality rates after stem
cell transplant compared with
the general population
mortality rates by
applying a standardised
mortality ratio of 2.34.
This reduced the
cost effectiveness
of liposomal
cytarabine–
daunorubicin.
The ERG considered
that this scenario
had face validity and
therefore included it
in its preferred analysis.
The clinical experts stated
that it was generally accepted
that survival would be shorter for people
who had a stem cell transplant than for
the general population. The committee
concluded that it was appropriate to
increase the mortality rate after stem cell
transplant in the model to higher than that
of the general population.
Utility values in the economic model
The utility values do not have a big effect
on the cost-effectiveness results.
Because health-related quality-of-life
data were not collected in Study 301,
the company used a time-trade-off
study to derive utility values for the
economic model. The treatment-related
disutilities included in the model were
based on descriptions of the side effects
of treatment provided by clinicians for
8 | 2019 | hospitalpharmacyeurope.com
the time-trade-off study. These described
a more favourable side-effect profile for
liposomal cytarabine–daunorubicin than
for standard cytarabine and daunorubicin.
Therefore a smaller disutility was applied
to the liposomal cytarabine–daunorubicin
group than the standard cytarabine and
daunorubicin group. The ERG highlighted
that this did not reflect the data from
Study 301. Therefore it estimated the mean
utility value for each treatment phase and
applied this to both treatment groups. The
ERG also noted that the utility value used
by the company for the remission
after transplant health state
was higher than usually
reported for the general
population. The
company also did
a scenario analysis
using utility values
from a study by
Hensen et al. (2017).
In this scenario,
the utility value for
the remission after
transplant health
state was 0.75, and the
ERG used this value in its
preferred analysis. The ERG
also adjusted the utility values
for age. The committee noted that these
changes did not have a big effect on the
cost-effectiveness results. It concluded that
it was plausible to assume the disutilities
were the same in both treatment groups, to
use a utility value of 0.75 for the remission
health state and to adjust the utility values
for age.
Costs and resource use in the
economic model
Costs and resource use in the economic
model do not have a big effect on the cost-
effectiveness results.
The company calculated treatment doses
and vial use including wastage, based
on a mean body surface area of 1.79m 2 ,
calculated from a UK study of adults with
cancer (Sacco et al. 2010). The ERG used
concluded that the company’s approach
was appropriate for decision making.