Barrett C, Willcocks LC, Jones RB, et al. - Researchers undertook this prospective, open-label, experimental medicine study to assess how belimumab influences proteinuria as well as anti-phospholipase A2 receptor autoantibodies (PLA2R-Ab) among patients with primary membranous nephropathy (PMN). Participants were 14 patients with PMN and persistent nephrotic-range proteinuria. These patients were administered belimumab monotherapy (10 mg/kg, every 4 weeks) up to 2 years. At Weeks 28 and 104, a reduction in proteinuria was evident from a baseline value of 724 mg/mmol to 498 mg/mmol and 130 mg/mmol, respectively, in the intention-to-treat population population, with alterations statistically significant from Week 36. At Weeks 28 and 104, a reduction in PLA2R-Ab from 174 RU/mL at baseline to 46 RU/mL and 4 RU/mL, respectively, was noted, which became statistically significant by Week 12. Based on the findings, it was concluded that in patients with PMN, treatment with belimumab can result in decrease in PLA2R-Ab and subsequently proteinuria, essential preludes to remission induction.