Safety profile of efgartigimod from global clinical trials across multiple immunoglobulin G-mediated autoimmune diseases

Efgartigimod is approved in multiple regions for the treatment of gMG, ITP, and CIDP, and is being evaluated in multiple IgG-mediated autoimmune diseases. Here, we report the long-term safety profiles of efgartigimod IV and PH20 SC across different dosing regimens and diseases where efgartigimod has received regulatory approval. Efgartigimod safety was assessed across dosing regimens and administration routes in Phase 2, placebo-controlled Phase 3, and OLE studies in participants with gMG, ITP, and CIDP. Analyses were performed on all participants who received ≥ 1 dose or partial dose of efgartigimod or placebo. Data from efgartigimod-treated participants were pooled per disease. Event rates were calculated as events per PYFU. Pooled data included 715 participants representing > 850 PYFU. In efgartigimod-treated participants, most TEAEs were mild-to-moderate in severity, with consistently low event rates for TEAE-related treatment discontinuation (range: 0.05-0.47). Severe and serious infection rates were comparable between placebo- and efgartigimod-treated participants. Rates of TEAEs, severe and serious infections, and treatment discontinuation did not increase with prolonged efgartigimod exposure. Efgartigimod did not reduce albumin or increase LDL cholesterol levels. Across clinical trials in IgG-mediated autoimmune diseases, efgartigimod was well tolerated with similar safety profiles regardless of dosing regimen.