Infliximab for the treatment of adults with psoriasis. Evidence Review Group Report for NICE's Single Technology Appraisal process

Abstract

This paper presents a summary of the evidence review group (ERG) report into the clinical and cost-effectiveness of infliximab for the treatment of moderate to severe plaque psoriasis, in accordance with the licensed indication, based on the evidence submission from Schering-Plough to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The outcomes stated in the manufacturer's definition of the decision problem were severity [Psoriasis Area and Severity Index (PASI) score], remission rates, relapse rates and health-related quality of life. The main evidence in the submission comes from four randomised controlled trials (RCT) comparing infliximab with placebo and eight RCTs comparing either etanercept or efalizumab with placebo.

At week 10, patients on infliximab had a significantly higher likelihood of attaining a reduction in PASI score than placebo patients. There were also statistically significant differences between infliximab and placebo in the secondary outcomes. In the comparator trials both the efalizumab and etanercept arms included a significantly higher proportion of patients who achieved a reduction in PASI score at week 12 than the placebo arms. No head-to-head studies were identified directly comparing infliximab with etanercept or efalizumab. The manufacturer carried out an indirect comparison, but the ERG had reservations about the comparison because of the lack of information presented and areas of uncertainty in relation to the included data.

The economic model presented by the manufacturer was appropriate for the disease area and given the available data. The cost-effectiveness analysis estimates the mean length of time that an individual would respond to infliximab compared with continuous etanercept and the utility gains associated with this response. The base-case incremental cost-effectiveness ratio (ICER) for infliximab compared with continuous etanercept for patients with severe psoriasis was £26,095 per quality-adjusted life-year. A one-way sensitivity analysis, a scenario analysis and a probabilistic sensitivity analysis were undertaken by the ERG.

The ICER is highly sensitive to assumptions about the costs and frequency of inpatient stays for non-responders of infliximab. The guidance issued by NICE in August 2007 as a result of the STA states that infliximab within its licensed indication is recommended for the treatment of adults with very severe plaque psoriasis, or with psoriasis that has failed to respond to standard systematic therapies. Infliximab treatment should be continued beyond 10 weeks in people whose psoriasis has shown an adequate response to treatment within 10 weeks. In addition, when using the Dermatology Life Quality Index (DLQI), care should be taken to take into account the patient's disabilities, to ensure DLQI continues to be an accurate measure.

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Identifiers

ORCID for Keith Cooper: orcid.org/0000-0002-0318-7670

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