Efficacy of intravenous immunoglobulins (IVIg) in improving skin symptoms in patients with dermatomyositis: a post-hoc analysis of the ProDERM study.

Background: Dermatomyositis (DM) is a rare autoimmune disease characterized by skin involvement, with or without proximal muscle weakness. Recently, following the ProDERM study, intravenous immunoglobulin (IVIg) was approved for treatment of DM. Until ProDERM evidence from large, placebo-controlled studies supporting its use for dermatological symptoms, was lacking. Here we present efficacy data from ProDERM of IVIg versus placebo for treatment of the cutaneous aspect of DM. Methods: ProDERM was a double-blind, randomized, multicenter, Phase 3 study. In the First Period (Weeks 0-16), adults with active DM received 2.0 g/kg IVIg (Octagam 10%; Octapharma AG) or placebo every 4 weeks. In the open-label Extension Period (Weeks 16-40), all patients received IVIg for 6 additional cycles. Cutaneous disease was assessed using measures including modified cutaneous DM disease area and severity index activity (CDASI-A) and damage (CDASI-D) scores, and myositis disease activity assessment tool (MDAAT) including visual analogue scale (VAS). This trial is registered with ClinicalTrials.gov, NCT02728752. Findings: The study took place from February 2017 to November 2019. 95 patients received IVIg (N = 47) or placebo (N = 48) in the First Period. Together, 664 IVIg infusion cycles were administered (median dose, 2.0 g/kg). At Week 16, mean CDASI-A change from baseline was -9.36 (95% CI: -12.52, -6.19) in the IVIg group versus -1.16 (-3.32, 0.99) in placebo group (p < 0.0001). At the end of the Extension Period, mean changes from baseline were -10.44 (95% CI: -13.94, -6.94) and -10.03 (-13.12, -6.94), respectively. Similar changes were seen for CDASI-D and VAS of MDAAT. These observations were seen regardless of baseline disease severity. Interpretation: ProDERM is the first large prospective, randomized trial to demonstrate the efficacy of IVIg to improve the cutaneous manifestations of DM. IVIg treatment significantly improved dermatological symptoms in patients with DM, regardless of disease severity before treatment, suggesting that IVIg is effective for even the most severe cutaneous DM. Funding: This study was sponsored by Octapharma Pharmazeutika Produktionsges m.b.H.