Rivaroxaban for the treatment of deep vein thrombosis and ...

The manufacturer submitted a decision-analytic model constructed in Microsoft Excel(R).
The economic evaluation uses a Markov approach using eleven possible health states,
including venous thromboembolism recurrences, bleeding events and death.
The manufacturer presented two analyses. The primary analysis compared the use of
rivaroxaban against dual therapy LMWH/VKA delivered over three, six or twelve months in
patients with acute DVT. Following a request from the ERG during the clarification process,
the manufacturer submitted an exploratory cost-effectiveness analysis in a subgroup of cancer
patients having adapting the existing model framework.
For the primary analysis, the rates of bleeding events and VTE recurrences after treatment of
the index DVT (at which point patients were assumed to enter the model) were taken directly
from the EINSTEIN-DVT trial. The manufacturer used data from dual therapy LMWH/VKA
to represent the baseline risk of events, and applied a hazard ratio to estimate the risk of
events for patients treated with rivaroxaban. A systematic review of the literature was carried
out to identify effectiveness data to inform the long term rates of recurrence and mortality
once treatment has ceased.
The baseline risk of events for patients with cancer was derived from the economic model for
the whole population treated with rivaroxaban, adjusted for the increased risk of events in
cancer patients versus non cancer patients. The treatment effect estimated from the MTC
(median HR/OR) was then applied to estimate the risk of events in cancer patients treated
with LMWH only. The manufacturer also assumed a shorter life expectancy, to reflect the
poorer prognosis of cancer patients.
Costs relating to the treatment and management of VTEs and adverse events such as
bleedings were included in the economic model and were taken from official sources (such as
British National Formulary (BNF) or National Health Service (NHS) reference costs), with
reference to clinical expert opinion where appropriate. The utility values for the different
health states were identified through a systematic search of the literature and was taken from
different studies.
Costs and benefits were discounted at 3.5% per annum and the uncertainty was captured in
both univariate sensitivity analysis (SA) and probabilistic sensitivity analysis (PSA).
The manufacturer reported that rivaroxaban was dominant in patients treated for 3, 6 or 12
months, i.e. provide more quality adjusted life years (QALYs) at a lower cost.
The manufacturer reported that rivaroxaban had a 58.4% chance of being cost-effective at a
willingness to pay (WTP) of £20,000 per QALY gained in patients treated for 3 months. The
probabilities for patients treated for 6 and 12 months was 85.0% and 95.4% respectively.
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