To describe the clinical response to Eculizumab (ECU) and Efgartigimod (EFGA) in a real-life setting in patients with generalized Myasthenia Gravis (gMG).

ECU, a complement active monoclonal antibody, is reimbursed in Italy for anti-acetylcholine receptor antibody positive (AChR-Ab+) gMG patients showing persistent symptoms, despite therapy with  corticosteroids (CS) and ≥2 non-steroidal immunosuppressants (NSISTs). EFGA, a human IgG1 antibody Fc-fragment that blocks neonatal Fc receptor, is available in Italy through an expanded access program and treatment can be administered to both AChR-Ab+ and seronegative patients. 

We included patients receiving either Eculizumab or Efgartigimod as part of our clinic practice and retrospectively collected data on their MG status using the MG activities of daily living (MG-ADL), quantitative MG scale (QMG), previous and current therapies, adverse events, and concomitant medication use. 

We enrolled 16 patients treated with ECU and 17 with EFGA. Of the EFGA group, 9 were Ab-AChR positive and 8 were seronegative. Median follow-up was 197 days. Three patients treated with EFGA suspended treatment for lack of efficacy, and one for patient’s choice. 

Both treatments were well tolerated, with minor adverse events. By week 24, MG-ADL decreased by -5.7 points for ECU group and -6.1 for  EFGA (p=0.645); the QMG decreased by -7.2 for the ECU group and -2.7 for the EFGA (p=0.023). Mean prednisone reduction at follow-up was -15.3 mg for ECU and -5.6 mg for EFGA (p=0.026). Speed of CS reduction was -13.6 mg/month for ECU and -1.1 mg/month for EFGA (p=0.049). 

Eculizumab and Efgartigimod proved to be both effective treatments in a real world setting. Both treatments reduced MG-ADL and QMG in difficult to treat gMG patients. For both treatments, responder rate was higher than previously reported in clinical trials. With the limitations of a small sample size, CS sparing effect was higher with Eculizumab compared to Efgartigimod.