Abstract-Text (inkl. Referenzen)

Introduction Efgartigimod IV, a human IgG1 antibody Fc-fragment blocking the neonatal Fc receptor, was effective and well tolerated in the ADAPT trial of generalized myasthenia gravis (gMG) patients. ADAPT-SC compares efgartigimod PH20 SC injections (coformulated with recombinant human hyaluronidase PH20) with efgartigimod IV infusions in gMG patients.

Methods 110 adults were randomized and treated with 4-weekly injections of efgartigimod PH20 SC 1000mg or 4-weekly IV infusions 10mg/kg. Primary endpoint: reduction (%) from baseline in total IgG at day 29 (noninferiority margin: 10%). Secondary endpoints: clinical efficacy (MG-ADL scale) and safety.

Results Efgartigimod PH20 SC demonstrated noninferiority to efgartigimod IV, with observed mean[SE] reductions in total IgG from baseline–day 29 (SC:–64.7%[1.95]; IV:–62.3%[1.24]). Similar improvements in MG-ADL score from baseline–week 4 were observed (mean[SE] improvement, SC:–5.1[0.38]; IV:–4.7[0.37]). Both formulations were well tolerated. Most frequent AEs were headache (12.7%SC and IV), injection site rash (14.5%SC; 0%IV), and injection site erythema (12.7%SC; 0%IV). Injection site reactions were predominately mild-moderate and did not lead to treatment discontinuation.

Summary ADAPT-SC demonstrated noninferiority of efgartigimod PH20 SC to efgartigimod IV (total IgG reduction). Both formulations were well tolerated. The efgartigimod PH20 SC formulation provides potential for an additional administration route for gMG patients.