Cost-effectiveness of infliximab for the treatment of active and progressive psoriatic arthritis.

BACKGROUND

Despite its proven efficacy, infliximab is often considered to be an expensive treatment for patients with psoriatic arthritis.

OBJECTIVES

To estimate the cost-effectiveness of infliximab among patients with active and progressive psoriatic arthritis.

METHODS

A decision analytic model was constructed to simulate disease progression in hypothetical cohorts of patients with psoriatic arthritis receiving infliximab maintenance treatment. The primary response measure was change in Health Assessment Questionnaire score from a baseline estimated from mixed treatment models drawn from published clinical trials. Palliative care, comprising nonbiologic disease-modifying antirheumatic drugs, was used as a comparator. The primary outcome was quality-adjusted life years. The dose of infliximab was estimated for a range of 60 to 80 kg per patient body weight. The costs and outcomes were discounted at 3.5% for a period of 40 years. Uncertainty around the results was explored with probabilistic sensitivity analysis.

RESULTS

The mixed treatment comparison showed a significant reduction in Health Assessment Questionnaire score across all patients. The tumor necrosis factor α inhibitors were significantly superior to palliative care but comparable with one another. The incremental cost-effectiveness ratios for etanercept, adalimumab, and infliximab relative to palliative care were £17,327; £19,246; and £16,942 to £23,022, respectively, across all patients with psoriatic arthritis and £16,613; £18,170; and £15,788 to £21,736, respectively, in the subgroup with significant psoriasis.

CONCLUSION

Infliximab represents a cost-effective treatment option well within the National Institute for Health and Clinical Excellence threshold relative to palliative care. In light of equivalent outcomes with other tumor necrosis factor α inhibitors, its position in the treatment pathway is likely to be governed by treatment costs.