GBR 830, an anti-OX40, improves skin gene signatures and clinical scores in patients with atopic dermatitis

GBR 830 is a humanized mAb against OX40, a costimulatory receptor on activated T cells. OX40 inhibition might have a therapeutic role in T cell–mediated diseases, including atopic dermatitis (AD). This exploratory phase 2a study investigated the safety, efficacy, and tissue effects of GBR 830 in patients with AD. Patients with moderate-to-severe AD (affected body surface area, ≥10%; Eczema Area and Severity Index score, ≥12; and inadequate response to topical treatments) were randomized 3:1 to 10 mg/kg intravenous GBR 830 or placebo on day 1 (baseline) and day 29. Biopsy specimens were collected (n = 40) at days 1, 29, and 71. Primary end points included treatment-emergent adverse events (TEAEs) and changes from baseline in biomarkers (epidermal hyperplasia/cytokines) at days 29 and 71. GBR 830 was well tolerated, with equal TEAE distribution (GBR 830, 63.0% [29/46]; placebo, 63.0% [10/16]). One serious TEAE in the GBR 830 group was deemed unrelated to study drug. At day 71, the proportion of intent-to-treat subjects achieving 50% or greater improvement in Eczema Area and Severity Index score was greater with GBR 830 (76.9% [20/26]) versus placebo (37.5% [3/8]). GBR 830 induced significant progressive reductions in TH1 (IFN-γ/CXCL10), TH2 (IL-31/CCL11/CCL17), and TH17/TH22 (IL-23p19/IL-8/S100A12) mRNA expression in lesional skin. Significant progressive reductions until day 71 in the drug group were seen in OX40+ T cells and OX40L+ dendritic cells (P