BACKGROUND: 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.; RESEARCH DESIGN AND METHODS: 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.;
RESULTS: 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.; CONCLUSIONS: Across clinical trials in
IgG-mediated autoimmune diseases, efgartigimod was well tolerated with similar safety
profiles regardless of dosing regimen.
