Background/Purpose: The optimal timing of high cost biologic therapies in the treatment of polyarticular juvenile idiopathic arthritis (JIA) is uncertain. We evaluated the economic and health outcomes of initial compared with step-wise use of anti-tumor necrosis factor (TNF) agent, etanercept (ETN), in this setting.

Methods: We conducted a cost-utility analysis of two strategies from a Canadian health care payer perspective. In one strategy, initial therapy was with methotrexate (MTX) alone. ETN was added in a step-wise fashion for patients who did not respond to MTX. In the other strategy, initial therapy was with MTX in combination with ETN; patients who did not respond switched to another anti-TNF agent. In both strategies, third and fourth line therapies were modeled with additional biological agents. Our base case was a 12-year-old child (weight 40 kg) with newly diagnosed polyarticular JIA naïve to disease-modifying and biological agents.  We simulated the course of the disease over 5 years using a Markov model with a cycle length of 1 month. Treatment response was defined as achieving an ACR Ped 70 response or better after 4 months of therapy. If this response was sustained over 12 months, without flare, patients entered a remission state. We derived model parameters, including treatment efficacy, disease flares, adverse events, costs, and quality of life weights from the medical literature.  Effects were calculated as quality-adjusted life years (QALYs); costs and QALYs were discounted at a rate of 3% per year. We conducted sensitivity analyses on all model parameters to assess the robustness of our results and used a $50,000/QALY threshold for cost-effectiveness.

Results: Our model predicted that the proportion of patients entering remission after 5 years was 89% with initial MTX and 93% with initial MTX and ETN combination. Median time to remission was 20 months in the MTX monotherapy group and 16 months in the combination group. The combination of initial MTX and ETN, compared to MTX alone, resulted in a discounted incremental cost of $14,498 per patient over 5 years and yielded a discounted incremental effect of 0.15 QALYs, for an incremental cost-effectiveness ratio of $97,517 per QALY. The results were sensitive to the cost of ETN and estimates of the efficacy of initial combination therapy.

Conclusion: Our model suggests that using initial combination therapy of MTX and ETN is unlikely to be cost-effective compared to using MTX alone, but more research is needed on key model parameters, including efficacy of initial anti-TNF agents and their impact on quality of life. A reduction in the cost of ETN by 33% would make initial use of this drug cost-effective.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/cost-effectiveness-analysis-of-early-biologic-treatment-in-polyarticular-juvenile-idiopathic-arthritis/