Adalimumab for the treatment of psoriasis

Abstract

This paper presents a summary of the evidence review group (ERG) report into the clinical and cost-effectiveness of adalimumab for the treatment of moderate to severe plaque psoriasis based upon a review of the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The submission's clinical evidence came from three randomised controlled trials comparing adalimumab with placebo, two extension studies and one ongoing open-label extension study. The studies were of reasonable quality and measured a range of clinically relevant outcomes. A higher proportion of patients on 40 mg adalimumab every other week achieved an improvement on the Psoriasis Area and Severity Index (PASI) of at least 75% (PASI 75) compared with placebo groups after 12 or 16 weeks of treatment, and there was a statistically significant difference in favour of adalimumab for the proportion of patients achieving a PASI 50 and a PASI 90. In a mixed treatment comparison, for each PASI outcome the probability of a response was greater for infliximab than for adalimumab, but the probability of response with adalimumab was greater than that with etanercept, efalizumab and non-biological systemic therapies. Adverse event rates were similar in the treatment and placebo arms and discontinuations because of adverse events were low and comparable between groups. The submission's economic model presents treatment effectiveness for adalimumab versus other biological therapies based upon utility values obtained from two clinical trials. The model is generally internally consistent and appropriate to psoriasis in terms of structural assumptions and the methods used are appropriate. The base-case incremental cost-effectiveness ratio for adalimumab compared with supportive care for patients with severe psoriasis was 30,538 pounds per quality-adjusted life-year. Scenario analysis shows that the model was most sensitive to the utility values used. Weaknesses of the clinical evidence included not undertaking a systematic review of the comparator trials, providing very little in the way of a narrative synthesis of outcome data from the key trials and not performing a meta-analysis so that the overall treatment effect of adalimumab achieved across the trials is unknown. Weaknesses of the economic model included that the assumptions made to estimate the cost-effectiveness of intermittent etanercept used inconsistent methodology for costs and benefits and there were no clear data on the amount of inpatient care required under supportive care. The NICE guidance issued as a result of the STA states that adalimumab is recommended as a treatment option for adults with plaque psoriasis in whom anti-tumour necrosis factor treatment is being considered and when the disease is severe and when the psoriasis has not responded to standard systemic therapies or the person is intolerant to or has a contraindication to these treatments.