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A systematic review of the effectiveness of adalimumab

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76<br />

Health economics<br />

TABLE 20 Summary <strong>of</strong> published ICERs for TNF inhibitor a (cont’d)<br />

Drug Comparator Study Date Time-horizon ICER<br />

Baseline level Kobelt163 2004 NA After 3 months <strong>of</strong> treatment €43,500 per QALY<br />

(failed at least<br />

two DMARDs,<br />

including MTX)<br />

After 6 weeks <strong>of</strong> treatment: €36,900 per QALY<br />

DMARD sequence Bansback 166 2005 Lifetime ACR50/DAS28 good:<br />

€48,333 per QALY (+ MTX)<br />

ACR20/DAS28 moderate:<br />

€64,935 per QALY (+ MTX)<br />

DMARD sequence Jobanputra 1 2002 Lifetime £115,937 per QALY<br />

Anakinra Chiou164 2004 1 year Infliximab + MTX dominated<br />

a Industry-sponsored studies are highlighted in shaded cells.<br />

b Cost-<strong>effectiveness</strong> analysis; all o<strong>the</strong>r studies are cost–utility analyses.<br />

Etan, etanercept; LEF, leflunomide; QALY, quality-adjusted life-year.<br />

is no response; leflunomide followed by etanercept<br />

if <strong>the</strong>re is no response to leflunomide (LEF–Etan);<br />

and finally, etanercept switching to leflunomide<br />

with non-response (Etan–LEF)]. Kobelt and<br />

colleagues 167 considered etanercept alone and<br />

etanercept combined with methotrexate.<br />

Two studies found high ICERs. Choi and<br />

colleagues 159 suggested that recommendations<br />

regarding use depended on whe<strong>the</strong>r an ICER over<br />

$40,000 per ACR20 or ACR70WR was considered<br />

acceptable. Welsing and colleagues 165<br />

recommended use <strong>of</strong> etanercept following<br />

leflunomide after two o<strong>the</strong>r DMARDs (where <strong>the</strong><br />

first is methotrexate) had failed. In contrast,<br />

Brennan and colleagues 160,168 reported a much<br />

lower ICER and suggested “etanercept was costeffective<br />

when compared with non-biologic<br />

agents”. Kobelt and colleagues 167 reported <strong>the</strong><br />

ICER for etanercept in combination with<br />

methotrexate to be within <strong>the</strong> “acceptable range”.<br />

Each study used a different modelling approach.<br />

Choi and colleagues 159 used a simple decision-tree<br />

structure and modelled costs and outcomes over 6<br />

months. Welsing and colleagues 165 and Kobelt and<br />

colleagues 167 used a Markov model structure with<br />

a 5-year time-horizon and a 5- and 10-year timehorizon,<br />

respectively. Brennan and colleagues 160<br />

developed an individual patient-level simulation<br />

model to calculate lifetime costs and outcomes.<br />

RCT data were used to model outcomes; it has<br />

been suggested that observational data are a more<br />

realistic representation <strong>of</strong> outcomes in practice<br />

and <strong>the</strong>refore more suitable for cost-<strong>effectiveness</strong><br />

analyses. 169<br />

Each study took different approaches; for<br />

example, <strong>the</strong> evaluation undertaken (cost-<br />

<strong>effectiveness</strong> or cost–utility analysis), <strong>the</strong><br />

treatment comparators and <strong>the</strong> time-horizon<br />

chosen (each used a different time-horizon,<br />

varying from 6 months to lifetime). Kobelt 167 used<br />

a cycle length <strong>of</strong> 1 year, which is not clinically<br />

relevant. A cycle length <strong>of</strong> around 4 months is<br />

more clinically relevant as decisions about<br />

<strong>the</strong> efficacy <strong>of</strong> DMARDs are generally made<br />

over this time. Three analyses were from a<br />

societal perspective, an approach that leads to a<br />

more favourable ICER. If a treatment is more<br />

effective, <strong>the</strong>n patients are more able to work,<br />

thus leading to lower indirect costs. The Choi<br />

study 159 did not calculate cost per QALYs,<br />

<strong>the</strong>refore comparison with o<strong>the</strong>r results is not<br />

possible.<br />

Two <strong>of</strong> <strong>the</strong> ten identified published studies report<br />

an economic analysis <strong>of</strong> infliximab in combination<br />

with methotrexate (Table 22), and were sponsored<br />

by <strong>the</strong> manufacturer Schering-Plough. Both<br />

studies were cost–utility analyses using a societal<br />

perspective and <strong>the</strong> comparator explored was<br />

methotrexate alone. The quality <strong>of</strong> life data used<br />

by Wong and colleagues 161 was based on selfreported<br />

global health using a visual analogue<br />

scale (VAS) from ATTRACT and <strong>the</strong> Arthritis,<br />

Rheumatism and Aging Medical Information<br />

System (ARAMIS) database. However, <strong>the</strong>re are<br />

problems with VAS such as context bias and endpoint<br />

aversion, and <strong>the</strong> method is not truly<br />

preference based. O<strong>the</strong>r methods are more<br />

appropriate, for example using a utility measure<br />

such as EuroQol 5 Dimensions (EQ-5D).<br />

Therefore, results should be treated with some<br />

caution. Costs were obtained from <strong>the</strong> ARAMIS<br />

database, based on a North American population,<br />

and are not directly transferable to a UK

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