Economic evaluation of tocilizumab monotherapy compared to adalimumab monotherapy in the treatment of severe active rheumatoid arthritis.

OBJECTIVES: To estimate the cost-effectiveness of tocilizumab (TCZ) monotherapy (Mono) versus adalimumab (ADA) Mono from the US payer perspective in patients with rheumatoid arthritis for whom methotrexate is inappropriate. METHODS: We compared TCZ Mono (8 mg/kg monthly) with ADA Mono (40 mg every other week), using efficacy results from a head-to-head study, ADalimumab ACTemrA (ADACTA). We calculated the incremental cost per responder (achievement of American College of Rheumatology [ACR] 20% improvement criteria, ACR 50% improvement criteria, ACR 70% improvement criteria, or low disease activity score) for TCZ versus ADA at 6 months. A patient-level simulation was used to estimate the lifetime incremental cost per quality-adjusted life-year (QALY) of initiating treatment with TCZ Mono versus ADA Mono. Both drugs are followed by an etanercept-certolizumab-palliative care sequence. Nonresponders discontinue at 6 months; responders experience a constant probability of discontinuation. Discontinuers move to the next treatment. ACR responses produce changes in the Health Assessment Questionnaire (HAQ) score. We mapped the HAQ score to utility to estimate QALYs. Costs include those related to hospitalization and those related to treatment (drug acquisition, administration, and monitoring). Probabilistic and one-way sensitivity analyses were conducted, along with several scenario analyses. RESULTS: Compared with ADA, TCZ was more effective, with an estimated 6-month incremental cost ranging from $6,570 per additional low disease activity score achiever to $14,265 per additional ACR 70% improvement criteria responder. The lifetime incremental cost-effectiveness ratio was $36,944/QALY. CONCLUSIONS: TCZ Mono is projected to be cost-effective compared with ADA Mono in patients with severe rheumatoid arthritis for whom methotrexate is not appropriate, from a US payer perspective.