Background Biological therapies (BT) have been a breakthrough in the treatment of psoriasis. Compared to conventional therapies, biologics are more effective but expensive in treating psoriasis.

Purpose To estimate the incremental cost-effectiveness ratios (ICERs) of BT licensed in Spain (infliximab, adalimumab, etanercept, ustekinumab, secukinumab e ixekizumab) in the management of moderate-to-severe psoriasis.

Material and methods A decision tree was performed for each BT, which were based on the outcomes from the clinical trials. Data on efficacy, reported in the randomised controlled trial, were the proportion of patients with a 75% reduction in the Psoriasis Area and Severity Index Score (PASI 75).

Total drug direct costs were calculated from the exmanufacturer (Botplus web; September 2017) – official discount (Royal decree law 8/2010)+VAT (4%). In the case of weight-dependent doses (infliximab) a standard patient weight of 70 kg has been considered. In addition, direct costs were added: processing and administration. For the remaining of BT, these costs are not relevant. The payer perspective (Spanish National Health System) was considered. The time horizon is the duration of each clinical trial.

We calculated the base case ICERs of biological therapies according to the incremental efficacy when compared to placebo in terms of PASI 75. We also calculated the worst and best case ICERs based on the lower and upper 95% confidence limits of the incremental efficacy respectively.

Results The ICERs per responder PASI 75 gained were:

• Infliximab: €5.282 in the base case (BC), €4.920 in the best case (BTC) and €5.701 in the worst case (WC).

• Etanercept: €8.710 (BC), €6.038 (BTC) and €15.619 (WC).

• Adalimumab: €7.277 (BC), €5.995 (BTC) and €9.256 (WC).

• Ustekinumab: €15.445 (BC), €14.120 (BTC) and €17.042 (WC).

• Secukinumab: €8.341 (BC), €3.639 (BTC) and €16.616 (WC).

• Ixekizumab: €7.603 (BC), €7.303 (BTC) and €7.929 (WC).

Conclusion Based on the ICER as to the PASI 75 response, infliximab had the best cost effectiveness in the base case for a standard patient weight of 70 kg, followed by adalimumab. It could be necessary to make this study for infliximab with others weights. The present analysis can be useful in making therapeutic decisions, which in any case must be individualised for each patient.

No conflict of interest