OBJECTIVES:  Biologic treatment options for psoriasis are increasing. Two new biologics, secukinumab and ixekizumab, both targeting the IL-17 pathway, have been recently approved. This study aimed to estimate the cost-effectiveness of sequential treatment with biologics in the United Kingdom incorporating these two treatments. METHODS:  A de novo Markov model was constructed using monthly cycles and four health states: trial, maintenance, best supportive care (BSC) and death. A comparison of an ixekizumab sequence (ixekizumab 80mg – ustekinumab 90mg – infliximab 5mg/kg – BSC) against a secukinumab sequence (secukinumab 300mg – ustekinumab 90mg – infliximab 5mg/kg – BSC) was performed. Tunnel states were used to model the trial period. At the end of the trial period, responders (defined as PASI75, at least a 75% reduction in baseline Psoriasis Area and Severity Index score) transitioned to maintenance therapy; non-responders (<PASI75) transitioned directly to the trial period of the next sequential treatment. All-cause discontinuation from maintenance was set at 20% annually. Discontinued patients transitioned to the trial period of the next therapy in the sequence. List prices for modelled interventions were obtained from the British National Formulary and MIMS, and the cost for BSC was taken from a published UK study (Fonia et al. 2010). Resource use associated with biologic treatments was obtained from NICE clinical guidelines. PASI response rates were obtained from a network meta-analysis, and the link between PASI response and utility gains were estimated from the ixekizumab UNCOVER trials. RESULTS:  With a lifetime time horizon, the ixekizumab sequence was dominant over the secukinumab sequence. Ixekizumab had an incremental benefit of 0.03 QALYs, and saved £943 compared to secukinumab. Sensitivity analyses indicated that the results were robust in the conclusion of dominance. CONCLUSIONS:  The model demonstrated that as a first-line treatment in a biologic sequence, ixekizumab is cost-effective vs secukinumab.