A cost-effectiveness analysis of treatment options for patients with methotrexate-resistant rheumatoid arthritis.
OBJECTIVE
Recently, new treatment options for rheumatoid arthritis (RA) patients with an inadequate response to methotrexate (MTX) have become available. Given the wide variability in efficacy and costs among these different treatment options, we sought to determine their cost-effectiveness (CE) in order to guide policy in different cost-constrained settings.


METHODS
We performed a CE analysis comparing 6 treatment options for patients with MTX-resistant RA: 1) etanercept + MTX, 2) etanercept monotherapy, 3) cyclosporine + MTX, 4) triple therapy (hydroxychloroquine, sulfasalazine, and MTX), 5) continuation of MTX monotherapy, and 6) no second-line agent. A decision model was used with a time horizon of 6 months. We used 2 measures of effectiveness based on published clinical trial data: the American College of Rheumatology 20% response criteria (ACR 20); and a weighted average of proportions of patients achieving responses of ACR 70, ACR 50, and ACR 20 (ACR 70 weighted response [ACR 70WR]). Incremental CE ratios were calculated as the additional cost per patient achieving either outcome, compared with the next least expensive option. To help interpret CE relative to these RA-specific outcomes, we conducted a separate, "reference" CE analysis of MTX use in MTX-naive RA patients, using the same outcomes.


RESULTS
In our reference analysis, MTX therapy for MTX-naive RA cost $1,100 per ACR 20 outcome and $1,500 per ACR 70WR, compared with no second-line agent. In our base-case analysis with either outcome, MTX continuation, cyclosporine + MTX, and etanercept monotherapy cost more, but either were not more efficacious or had a higher incremental CE ratio than the next most expensive option (i.e., they were dominated). Therefore, these options were not cost-effective. The least expensive option, triple therapy, cost 1.3 times more per patient with ACR 20 outcome ($1,500/ACR 20) and 2.1 times more per ACR 70WR ($3,100/ACR 70WR) than MTX therapy for MTX-naive RA. The most efficacious option, the combination of etanercept and MTX, cost 38 times more per patient with ACR 20 outcome ($4,600/ACR 20) and 23 times more per ACR 70WR ($34,800/ACR 70WR) than MTX therapy for MTX-naive RA. Overall, the results of extensive sensitivity analyses did not substantially affect these results.


CONCLUSION
Our analysis indicates that if 15 mg/week MTX is cost-effective for achieving ACR 20 or ACR 70WR in MTX-naive RA over a 6-month period, then most likely so is triple therapy in MTX-resistant RA. Whether etanercept + MTX is cost-effective depends on whether $34,800/ACR 70WR (or $42,600/ACR 20) over a 6-month period is considered acceptable.