Biologics in congenital ichthyosis: are they effective?

Abstract Background Congenital ichthyoses comprise a heterogeneous group of genetic diseases that require lifelong treatment and have a major impact on patients’ quality of life. Conventional treatments reduce scaling and skin discomfort; however, they usually have little or no effect on erythema and pruritus. The identification of cytokine alterations in congenital ichthyoses has raised the possibility of repurposing currently available biologics. Several case reports have reported success with different biologics. Objectives To report the real-life effects of biologics on congenital ichthyoses. Methods This was a retrospective observational international multicentric study of patients with congenital ichthyoses treated with at least one biologic for a minimum of 3 months. The effect of the biologics was evaluated using an Investigator Global Assessment for change (IGA-C) scale. A comprehensive literature search was performed in parallel. Results Ninety-eight patients were included [mean (SD) age of 19.7 years, 50 female patients]. Patients with Netherton syndrome (NS) or congenital ichthyosiform erythroderma (CIE) represented the majority of patients (30% and 21%, respectively). Most patients (85%) had a severe or very severe form of congenital ichthyoses. The most frequently used biologics were inhibitors targeting interleukin (IL)-17, IL-12/IL-23 or the IL-4 receptor (IL-4R). The mean (SD) duration of treatment was 22.1 (20.1) months. There were 45 responders (46%), including 18 (18%) who were good responders; all had a subset of erythrodermic congenital ichthyoses and received one of the three main biologics. In patients with NS and CIE, IL-12/IL-23 and IL-4R inhibitors tended to be most effective. The literature review revealed a shorter mean (SD) duration of biologic treatment [11.5 (8.5) months] and higher percentage of responders (86%), suggesting reporter bias. Conclusions This series identified subsets of congenital ichthyoses that may respond to biologics and will help with the design of future clinical trials of biologics for congenital ichthyoses.