Objective: New treatment options for patients with methotrexate (MTX)-naive rheumatoid arthritis (RA) have become available. Given wide variability in efficacy and cost among different treatment options, we sought to determine their relative cost effectiveness to help guide policy in different cost constrained settings.
Methods: We performed a cost effectiveness analysis comparing 5 monotherapy options for patients with MTX-naive RA: (1) etanercept, (2) leflunomide, (3) MTX (up to 15 mg weekly), (4) sulfasalazine (SSZ), and (5) no second line agent. A decision analysis model was used with a time horizon of 6 months. We employed 2 measures of effectiveness based on published clinical trial data: American College of Rheumatology (ACR) 20% response proportion (ACR 20) and a weighted average of proportions achieving ACR 70, ACR 50, and ACR 20 (ACR 70 weighted response, ACR 70WR). Incremental cost effectiveness ratios were calculated as additional cost per patient achieving either outcome, compared with the next most expensive option.
Results: In both base case analyses employing ACR 20 and ACR 70WR as effectiveness measures, MTX and SSZ both cost less and were more effective (i.e., cost saving) than no second line agent. Leflunomide cost more and was less efficacious than SSZ (dominated) in analyses using either outcome. The most efficacious option, etanercept, cost US $41,900 per ACR 20 and $40,800 per ACR 70 WR compared with SSZ and MTX, respectively. When we included only direct costs in analyses, the least expensive non-dominated option was SSZ with incremental cost effectiveness ratios of US $900 per ACR 20 and $1500 per ACR 70WR compared with no second line agent. Overall, relative cost effectiveness between MTX and SSZ was sensitive to variation in relevant variables in sensitivity analyses. Otherwise, our extensive sensitivity analyses did not substantially affect the base case results.
Conclusion: MTX is cost effective (cost saving vs the no second line agent option) for MTX-naive RA in achieving ACR 20 or ACR 70WR over a 6 month period. Based on available data, the relative cost effectiveness between SSZ and MTX cannot be determined with reasonable certainty and SSZ therapy appears to be as cost effective as MTX (cost saving) in achieving ACR outcomes over a 6 month period. The most efficacious option, etanercept, incurs much higher incremental costs per ACR 20 or ACR 70WR than other options analyzed. Whether etanercept compared with MTX is cost effective depends on whether > $40,000 per ACR 20 or ACR 70WR over a 6 month period is considered acceptable.