Abstract: SA-PO694
Economic Evaluation of Azathioprine vs. Rituximab in ANCA-Vasculitis in the United States
Session Information
- Glomerular Diseases: Clinical, Outcomes, Trials - III
November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1303 Glomerular Diseases: Clinical‚ Outcomes‚ and Trials
Authors
- Ehlert, Lexy, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Derebail, Vimal K., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Hogan, Susan L., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
- Aspinall, Sherrie L., VA Center for Health Equity Research and Promotion, Pittsburgh, Pennsylvania, United States
- Thorpe, Carolyn T., The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
Background
Research indicates that rituximab (RTX) is superior to azathioprine (AZA) as a maintenance therapy in preventing relapse among patients in remission for ANCA-vasculitis (AV), including granulomatosis with polyangiitis, microscopic polyangiitis, and renal-limited disease. Some guidelines recommend RTX as first-line therapy, with AZA as second-line therapy. Because RTX is 15.5 times as expensive as AZA, we sought to evaluate the cost-effectiveness of RTX vs. AZA as a maintenance therapy in AV, from a U.S. payer, or health plan, perspective.
Methods
We used a 10-year Markov model with a hypothetical cohort of 10,000 patients. In this model, patients moved through four health states (see Figure). Model inputs included health state transition probabilities; probabilities of infection, cancer, and cardiovascular events; costs of treatment and outcomes; health state utility weights; and cost/utility discount rates. We did not include end-stage kidney disease, likely captured by relapse/death. Model outputs were years patients spent in relapse, deaths, costs, and quality-adjusted life-years (QALYs). We conducted a one-way sensitivity analysis to account for wide variation in medication costs.
Results
Therapy-specific results are reported in the Table. The incremental cost of RTX treatment was $171 million. The cost per major relapse year averted was $63,018 and the cost per death averted was $142,869. The cost per QALY gained was $43,936. In our one-way sensitivity analysis, we found that if payers pay 100% of the listed drug price, then the cost per QALY gained is ~$44,000. If drug costs can be reduced to 50% of current listed price, then the cost per QALY gained is ~$15,000.
Conclusion
Though RTX is associated with better health outcomes in this population, $44,000/QALY may be above the willingness-to-pay threshold for some U.S. payers. Efforts to reduce RTX cost can help payers stay within their WTP range and decrease overall healthcare spending.
| Treatment Arm | Minor Relapse Years | Major Relapse Years | Deaths | QALYs |
| Azathioprine | 4,993 | 15,530 | 2,103 | 53,065 |
| Rituximab | 5,043 | 12,813 | 904 | 56,963 |