Belimumab as a possible treatment for SLE-associated pulmonary arterial hypertension: the experience from a single centre

Objective To explore clinical outcomes associated with belimumab use in patients with SLE-associated pulmonary arterial hypertension (SLE-PAH).Methods We performed an ambispective cohort study of 10 patients with SLE-PAH treated with intravenous belimumab (10 mg/kg) from January 2022 to January 2025 and compared them with 30 matched SLE-PAH controls receiving conventional immunosuppression without biologics. Patients were followed for 12 months by the same medical team. Clinical, laboratory, echocardiographic parameters, SLE Disease Activity Index 2000 and PAH risk stratification were compared between groups.Results All patients were matched according to baseline age, sex, WHO functional class (WHO-FC), PAH treatment strategy and background SLE therapy. All enrolled patients received either dual or triple combination targeted therapy for PAH. In the SLE-PAH group treated with belimumab, rapid and sustained improvements were observed in multiple parameters, including N-terminal pro-B-type natriuretic peptide, WHO-FC, 6-minute walking distance, soluble suppression of tumorigenicity 2 levels, the ratio of tricuspid annular plane systolic excursion to pulmonary artery systolic pressure (TAPSE/PASP) and right ventricular end-diastolic basal dimension (RVDd). Compared with the matched control group, belimumab-treated patients showed greater improvement in TAPSE/PASP and RVDd at the 12-month follow-up, with statistically significant differences between groups. Additionally, at the 12-month follow-up, all patients in the belimumab group were stratified into the low-risk category, whereas one patient remained in the intermediate-low risk and four patients were categorised as intermediate-high risk in the matched group.Conclusion Belimumab combined with standard PAH-targeted therapy was associated with improvements in right ventricular structure and function in patients with SLE-PAH compared with conventional immunosuppression. Further large-scale, prospective investigations are warranted to confirm these findings.