Comparative Cost per Response for 4 Clinical Endpoints with Tocilizumab Monotherapy vs Adalimumab Monotherapy in a Head-to-Head Randomized Double-Blind Superiority Trial (ADACTA) in Patients with Rheumatoid Arthritis

INTRODUCTION: The cost-effectiveness of different biologic therapies can be an important component in guiding treatment decisions for patients with rheumatoid arthritis (RA). The objective of this study was to compare drug and adverse event costs and cost per successful clinical response with tocilizumab (TCZ) monotherapy vs adalimumab (ADA) monotherapy in patients with RA in a phase 4 clinical trial. METHODS: Patients received either TCZ intravenously every 4 weeks or ADA subcutaneously every 2 weeks for 24 weeks. Drug and administration costs were based on wholesale acquisition costs and the Centers for Medicare and Medicaid, respectively. Outcomes included patient-level drug costs, cost of hospitalization due to adverse events, and cost per response. Cost per response was calculated by dividing the mean drug plus administration cost by the proportion of patients achieving Disease Activity Score in 28 joints (DAS28) < 2.6 (remission) or 20%, 50%, or 70% improvement in response per the American College of Rheumatology (ACR20/50/70). Hospitalization costs were calculated using the daily hospital cost and number of hospital days. RESULTS: Among the 163 patients treated with TCZ and 162 patients treated with ADA, mean total drug and administration costs per patient over 24 weeks were $18,290.60 and $25,623.10, respectively. Mean drug and administration costs per each clinical response achieved were lower with TCZ than with ADA (DAS28 < 2.6: $45,868 vs $244,174; ACR20: $28,127 vs $51,887; ACR50: $38,720 vs $92,244; ACR70: $56,253 vs $143,136). The total hospital days were 32 days with TCZ and 43 days with ADA; mean hospital costs per patient were $484.50 with TCZ and $651.10 with ADA. CONCLUSION: In this comparative assessment, the cost to achieve all 4 clinical endpoints was lower for patients receiving TCZ than for those receiving ADA.