Abstract: AIM: Belimumab is a fully humanized IgGl-X monoclonal antibody, which can specifically bind to soluble B cell stimulating factor (BLyS) preventing BLyS from binding to B cells to promote B cell apoptosis. It is the first drug approved by the FDA for the treatment of systemic lupus erythematosus (SLE). Based on data from global clinical literature of the drug, this study evaluated the effect of belimumab in the treatment of SLE through modeling analysis, quantitatively expressed its pharmacodynamic characteristics, and explored its potential influencing factors to establish the efficacy of belimumab in the treatment of SLE, which could provide a reference for the development of drugs for the treatment of SLE.  METHODS: Literature retrieval was conducted in Pubmed database. The clinical studies of belimumab in the treatment of SLE were included. Data, including the demography and baseline characteristics, dosage, administration methods, efficacy and safety of belimumab, was extracted to establish an analysis sets. Then a pharmacodynamic model was developed to evaluate the pharmacodynamic characteristics of the drug. The robustness of the model was evaluated via a variety of model evaluation methods. RESULTS: A total of 5 articles containing efficacy data were included in this analysis, involving 11 dosage groups (3 493 subjects). The results of covariate screening showed that race (Asian population or non-Asian population), age, course of disease, positive anti-dsDNA had no significant effect on the therapeutic effect of belimumab in SLE and there were no factors that had significant influence on model parameters. Model evaluation showed that the model established in this study can better describe the dose-effect relationship of belimumab in the treatment of SLE. The final model indicated that the response rate of the efficacy index SRI was close to the peak (approximately 99% of the peak level) at the 52nd week. The SRI response rates of placebo, belimumab 1 mg/kg intravenous injection, 10 mg/kg intravenous injection, and 200 mg subcutaneous injection were 46.1%, 52.9%, 57.9%, and 60.9%, respectively. After deducting the placebo effect, the SRI response rates (drug pure effect) of belimumab 1 mg/kg intravenously, 10 mg/kg intravenously, and 200 mg subcutaneously at 52 weeks were 6.8%, 11.8%, and 14.8%, respectively. CONCLUSION: The efficacy (SRI response rate) of belimumab in the treatment of SLE patients was close to its peak in the 52nd week. The SRI response rates of belimumab 1 mg/kg intravenously, 10 mg/kg intravenously, and 200 mg subcutaneously in the 52nd week were 52.9%, 57.9%, and 60.9%, respectively.

Key words: belimumab, systemic lupus erythematosus, model based clinical evaluation