Indirect cost-effectiveness analyses of abatacept and rituximab in patients with moderate-to-severe rheumatoid arthritis in the United States

Abstract

Objective: To estimate the incremental cost per quality-adjusted life-years (QALYs) for abatacept and rituximab, in combination with methotrexate, relative to methotrexate alone in patients with active rheumatoid arthritis (RA).

Methods: A patient-level simulation model was used to depict the progression of functional disability over the lifetimes of women aged 55–64 years with active RA and inadequate response to a tumor necrosis factor (TNF)-α antagonist therapy. Future health-state utilities and medical care costs were based on projected values of the Health Assessment Questionnaire Disability Index (HAQ-DI). Patients were assumed to receive abatacept or rituximab in combination with methotrexate until death or therapy discontinuation due to lack of efficacy or adverse events. HAQ-DI improvement at month 6, after adjustments for control drug (methotrexate) response, was derived from two clinical trials. Costs of medical care and biologic drugs, discounted at 3% annually, were from the perspective of a US third-party payer and expressed in 2007 US dollars.

Results: Relative to methotrexate alone, abatacept/methotrexate and rituximab/methotrexate therapies were estimated to yield an average of 1.25 and 1.10 additional QALYs per patient, at mean incremental costs of $58,989 and $60,380, respectively. The incremental cost-utility ratio relative to methotrexate was $47,191 (95% CI $44,810–49,920) per QALY gained for abatacept/methotrexate and $54,891 (95% CI $52,274–58,073) per QALY gained for rituximab/methotrexate. At an acceptability threshold of $50,000 per QALY, the probability of cost effectiveness was 90% for abatacept and 0.0% for rituximab.

Conclusion: Abatacept was estimated to be more cost effective than rituximab for use in RA from a US third-party payer perspective. However, head-to-head clinical trials and long-term observational data are needed to confirm these findings.

Key words::

• arthritis
• cost effectiveness
• tumor necrosis factor-alpha

Acknowledgment

Declaration of interest: This study was funded by Bristol-Myers Squibb Company (BMS), Plainsboro, NJ, USA. All authors are employed by BMS Company. The authors are grateful to Julia Vishnevetsky, in collaboration with SCRIBCO, for medical writing assistance. Some of this work was presented at the Annual European Congress of Rheumatology (EULAR), June 14, 2008, Paris, France.