OBJECTIVES: To estimate the cost-utility of BEL treatment of patients with SLE as an add-on therapy to intensive standard of care (SOC) vs. SOC in Poland. METHODS: The general population considered in the analysis were patients with SLE with significant disease activity, who met criteria of SLE diagnosis and were ineffectively treated with SOC. CUA was performed from the public payer perspective. The lifetime horizon was assumed. The decision model was developed in MS Excel and adjusted to Polish conditions. The calculations were performed using Monte Carlo microsimulation. The model included data from international clinical studies and Polish data on costs and resource utilization. Direct medical costs were included: costs of drugs, administration, diagnostic, monitoring and costs related to disease activity.Results were calculated for two patients populations: target population 1 (TP1) - patients with positive anti-dsDNA, low complement and ≥10 scores in SELENA-SLEDAI scale and target population 2 (TP2) - patients with positive anti-dsDNA, low complement, ≥6 scores in SELENA-SLEDAI scale and necessity of corticosteroids use. RESULTS: CUA results showed that BEL compared to SOC is more costly however, also more effective therapy. The ICUR was 113,986 PLN/QALY and 108,744 PLN/QALY, respectively for TP1 and TP2. Obtained results are placed slightly above the Polish acceptability threshold. Additional health effects related to BEL treatment instead of SOC were noticed both in LYG and QALY (0.432 and 0.4 LYG; 0.322 and 0.294 QALY, respectively for TP1 and TP2). Moreover, the model suggests lower frequency of cardiovascular events, and also pulmonary and renal complications in BEL arm. CONCLUSIONS: Since there is currently no effective treatment option of SLE in Poland, reimbursement of belimumab will give patients an access to a safe and effective therapy, which allows them to return to active life and career and also to improve their quality of life.