OBJECTIVES : Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease that is associated with long-term morbidity, increased mortality and reduced quality of life. This analysis evaluates the cost-effectiveness of tofacitinib, an oral Janus kinase inhibitor, compared to other commonly prescribed drug combinations for the treatment of moderate to severe RA in Singapore.

METHODS : A cost-utility model with patient-level simulations was used to assess the lifetime treatment costs and incremental cost-effectiveness ratio (ICER) of RA drug treatments. Taking reference from Chapter of Rheumatologists Consensus Guidelines, the model compared treatment sequence with tofacitinib to a comparator sequence without tofacitinib. Each treatment cycle was assumed to last six months, or earlier when patients switched or discontinued treatment due to a lack or loss of effectiveness, serious adverse events or death. Efficacy was measured by change in Health Assessment Questionnaire (HAQ) score. HAQ scores were used to predict mortality and resource utilization, and were mapped onto utility values to estimate QALYs. Efficacy and safety data were derived from clinical trials and other secondary sources. Costs (Singapore Dollars (S$)) were mainly obtained from fee schedule and price survey in pharmacy in Singapore public hospitals. Clinical and economic outcomes were estimated over a lifetime and discounted at 3% annually. Uncertainty in model parameters was explored using one-way deterministic and probabilistic sensitivity analyses.

RESULTS : First line tofacitinib with methotrexate (MTX) treatment option shows 0.13 more QALYs gained compared to adalimumab with (MTX) treatment option at the additional S$5,704. The ICER was S$42,540/QALY.

CONCLUSIONS : This cost-effectiveness analysis suggests that Tofacitinib is a cost-effective treatment option for the management of moderate to severe RA in Singapore.