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

the clarification process. Therefore, the daily acquisition cost for patients treated with rivaroxaban
was estimated to be £4.20 the first 21 days (15 mg twice a day), and £2.10 thereafter (20mg once a
day).
The drug acquisition cost for patients treated with LMWH and VKA was taken from the BNF. 48 The
daily cost for patients treated with enoxaparin (Clexane® used in the economic model) was calculated
to be £9.77 daily, assuming a 1.5 mg/kg daily dose and a mean weight of 80kg. The daily cost of
warfarin was calculated to be £0.07 once a day, assuming a daily maintenance dose of 6mg (the BNF
indicate a daily dose between 3-9 mg daily). 48
The ERG finds the approach used by the manufacturer to be satisfactory. As previously detailed
(section #), the manufacturer used exonaparin in the economic model as this is the most used LMWH
in England and Wales, was used in the EINSTEIN-DVT trial and can be self-administered.
Furthermore, the ERG calculated that the daily drug acquisition cost of Clexane® (£9.77) was similar
to the weighted average drug acquisition cost across LMWH used (£10.03 c ). The manufacturer
conducted sensitivity analyses where the price ranged within ±30% (encompassing the daily cost for
other LMWH) and showed that the conclusions remained unchanged. Finally, the manufacturer
assumed a mean weight of 80kg, instead of the 82kg observed in the trial, which has an impact only
for the cost of LMWH. 1,50 The clinical advisors to the ERG agreed that the assumption used by the
manufacturer were appropriate.
Administration
The manufacturer assumed in the economic model that rivaroxaban was self-administered.
The manufacturer further assumed that patient education would be successfully delivered to 92% of
patients taking Clexane® (enoxaparin) and these patients would be self-administered based on the
assumption used in NICE CG92 18 and therefore no costs was assumed for these patients. The
manufacturer did not include the costs of patient education.
Of the 8% of patients for whom patient education was unsuccessful, the manufacturer assumed that
80% are treated by a nurse at home using data from a survey. 58 The remaining are assumed to be
treated in clinic, with 7.5% requiring transportation (£30.86 – NHS reference costs).
Clinical opinion was sought and believed these assumptions to be reasonable. Note that there was a
discrepancy between the economic model and the report, as the manufacturer stated that 8.55% of
patients treated in clinic required transportation, but used 7.5% in the economic mode
c Calculated by the ERG
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