Efficacy, pharmacokinetics and safety of iscalimab (CFZ533) in patients with proliferative lupus nephritis: a randomised, double-blind, placebo-controlled, phase II study.

backgroundIscalimab (CFZ533) is a novel, anti-CD40 monoclonal antibody. This study evaluated the efficacy, pharmacokinetics and safety of iscalimab versus placebo as add-on to standard-of-care (SoC) therapy in patients with biopsy-proven active proliferative lupus nephritis (LN).

methodsThis was a phase II, randomised, double-blind, placebo-controlled, multicentre study including patients with a diagnosis of systemic lupus erythematosus with active LN. Patients were randomly assigned (2:1) to receive either intravenous iscalimab (10 mg/kg) or placebo for 24 weeks on top of SoC for LN. The primary efficacy endpoint was the ratio from baseline in urinary protein-to-creatinine ratio (UPCR) at week 24. Safety assessments included adverse events (AEs) and serious AEs (SAEs) during treatment and follow-up up to 49 weeks.

findingsOf the 57 patients (iscalimab, n=39; placebo, n=18) randomised, 31 (54.4%) completed the study. The primary efficacy endpoint was met: at week 24, the relative improvement from baseline in proteinuria (UPCR) was 63.1% and 36.3% in the iscalimab and placebo arms, respectively. UPCR to baseline at week 24 showed a statistically significant reduction of 42.1% in the iscalimab versus placebo arm. Most AEs were of mild to moderate severity in both treatment arms. Overall, seven SAEs were reported in six patients (15.4%) in the iscalimab arm versus four in three patients (16.7%) in the placebo arm.

interpretationIscalimab showed a significant improvement in proteinuria (UPCR) in patients with active LN. Iscalimab was generally well tolerated with the exception of a few severe infections and one case of macrophage-activation syndrome in immunosuppressed and comorbid patients. TRIAL REGISTRATION NUMBER: NCT03610516.