Phase I, randomized, double-blind, placebo-controlled, multiple intravenous, dose-ascending study of sirukumab in...

We undertook a 2-part, phase I, double-blind, placebo-controlled study to evaluate the safety and pharmacokinetics of multiple intravenous infusions of sirukumab, a human anti-interleukin-6 monoclonal antibody, in patients with cutaneous lupus erythematosus (CLE) or systemic lupus erythematosus (SLE).

In part A, patients with histologically confirmed CLE were randomized to 4 infusions of placebo or 1, 4, or 10 mg/kg sirukumab every 2 weeks. In part B, SLE patients diagnosed according to American College of Rheumatology criteria with a score of 5-12 on the Safety of Estrogens in Lupus Erythematosus National Assessment version of the SLE Disease Activity Index were randomized to 4 infusions of placebo or 10 mg/kg sirukumab every 2 weeks.

We treated 31 CLE patients (23 with sirukumab, 8 with placebo) and 15 SLE patients (10 with sirukumab, 5 with placebo). Adverse events (AEs) occurred more often with sirukumab than placebo in CLE patients (91% versus 63%) and in SLE patients (90% versus 80%). Sirukumab led to sustained, dose-independent decreases in white blood cell counts, absolute neutrophil counts (neutropenia), and platelet counts (thrombocytopenia) and to minor elevations in total cholesterol levels. The majority of infections were mild respiratory infections. which were reported similarly across CLE cohorts but more often in sirukumab-treated than in placebo-treated SLE patients. Two serious AEs of infection occurred (pneumonia in the 10 mg/kg-treated group and iatrogenic wound infection in the 4 mg/kg-treated group). Sirukumab showed linear pharmacokinetics in CLE patients. Systemic exposure and half-life were comparable between CLE and SLE patients. No patient developed antibodies to sirukumab through 22 weeks. C-reactive protein and serum amyloid A mean concentrations were suppressed with sirukumab from week 1 to week 14.

Treatment with intravenous sirukumab infusions was generally well tolerated in both CLE and SLE patients with mild, stable, active disease. Sirukumab demonstrated linear pharmacokinetics over the dose range studied and comparable systemic exposure and half-life in CLE and SLE patients.