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Objective: Efgartigimod, a neonatal Fc receptor antagonist, facilitates antibody degradation including pathogenic IgGs. The ADAPT study demonstrated the tolerability and efficacy of efgartigimod in the treatment of generalized myasthenia gravis (gMG). However, very limited evidence is available for the Chinese population, and it remains inconclusive about which kind of patients are selected to preferentially receive efgartigimod in real-world settings., Methods: This multicenter cohort study included gMG patients treated at 14 neuromuscular reference centers in China. The Myasthenia Gravis Activities of Daily Living (MG-ADL) score, immunosuppressants, and the incidence of treatment-emergent adverse events (TEAEs) were prospectively collected., Results: Of the 1640 gMG admitted between September and December 2023, 61 (3.7%) received efgartigimod for at least one treatment cycle. Among them, 56 cases (92%) were anti-AChR antibody-positive, 4 were anti-MuSK antibody-positive, and 1 was seronegative. Thymoma-associated myasthenia gravis accounted for most cases (44%, 27 out of 61). The principal causes of efgartigimod initiation included MG acute exacerbation (MGAE) (48%, 29 out of 61) and myasthenic crisis (MC) (15%, 9 out of 61). Clinically meaningful improvement was rapidly achieved in 97% (58 out of 61) of patients at 1.3 ± 0.7 weeks. By week 12, the MG-ADL score reduced to 3.8 ± 4.1 (baseline:10.5 ± 5.2) for all participants, while it reduced to 4.0 ± 4.7 for MGAE and 3.8 ± 4.2 for MC, respectively. All but one TMG patient required no additional rescue therapies after efgartigimod initiation. 11.5% (7 out of 61) reported ≥1 TEAEs., Interpretation: This multicenter cohort study demonstrated the efficacy of efgartigimod in rapid control of gMG. Patients with MGAE or MC would benefit from efgartigimod treatment., (© 2024 The Author(s). Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Background: Efgartigimod is an approved biologic for generalized myasthenia gravis (gMG), which is an autoimmune disease and can potentially be life-threatening. However, the therapeutic response to efgartigimod among the acetylcholine receptor gMG (AChR-gMG) subtypes remains inconclusive. Objective: To explore the patterns and predictors for the therapeutic response to efgartigimod among AChR-gMG subtypes. Design: This prospective, observational study included AChR-gMG patients treated with efgartigimod at 15 centers in China with a follow-up for at least 20 weeks. Methods: The primary outcome was the proportion of minimal symptom expression (MSE) responders, denoted by a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 0 or 1 within 4 weeks and maintained for ⩾4 weeks. AChR antibody-positive MG (AChR-MG) subtypes were classified into early onset myasthenia gravis (EOMG), late-onset myasthenia gravis (LOMG), and thymoma-associated myasthenia gravis (TAMG). The predictive factors for MSE responders were identified by univariate and multivariate logistic regression analysis. Results: One hundred sixteen patients were included with a median follow-up duration of 238 days (172.5–306.3). There were 50 (43.1%) patients with EOMG, 28 (24.1%) with LOMG and 38 (32.8%) with TAMG. After efgartigimod initiation, 35 (30.2%) patients were MSE responders, and the proportion of MSE responders was highest in the LOMG group (42.9%). The MG-ADL score reduction in the LOMG group was more significant than in the EOMG group by weeks 16 and 20 (both p = 0.022). Response patterns to efgartigimod among the AChR-MG subtypes differed as measured by the proportion of improved patients and MSE. LOMG presented sustained symptom control, while EOMG and TAMG showed more fluctuations. Eight TAMG patients (21.1%) switched to another biologic (p = 0.005). Baseline MG-ADL was an independent predictor for therapeutic response to efgartigimod (p < 0.001). Conclusion: Our findings revealed patterns of treatment responses among AChR-gMG subtypes, with LOMG patients potentially presenting a more sustained response. These findings likely provide preliminary data for precision therapy in MG in the era of biologics. Trial registration: NCT04535843. Plain language summary: Patterns and predictors of therapeutic response to efgartigimod in AChR generalized myasthenia gravis Myasthenia Gravis (MG) is an autoimmune disorder that can lead to potentially life-threatening complications. Efgartigimod is an approved biologic for generalized myasthenia gravis (gMG). However, the patterns and predictors of therapeutic response to efgartigimod among the acetylcholine receptor-generalized MG (AChR-gMG) subtypes remain inconclusive. Our findings revealed patterns of treatment responses among AChR-gMG subtypes, with LOMG patients potentially presenting a more sustained response. [ABSTRACT FROM AUTHOR]

Background: Thymoma-associated myasthenia gravis (TAMG) is a subtype of myasthenia gravis (MG) that is associated with more severe symptoms and a relatively poor prognosis. Eculizumab, an inhibitor to target human C5 component of the complement cascade, is considered a treatment option for refractory generalized MG (gMG). Objectives: To explore the safety and efficacy of eculizumab in patients with TAMG. Design: This is an observational multicenter real-world cohort study to assess TAMG who were treated with eculizumab from June 2023 to June 2024. Data sources and methods: Clinical features associated with thymoma-associated multi-organ autoimmunity (TAMA), Myasthenia Gravis Activities of Daily Living (MG-ADL) score, and the incidence of treatment-emergent adverse events (TEAEs) were prospectively collected. Results: Overall, 42 patients with gMG were treated with eculizumab at 5 research centers, of whom 22 patients with TAMG were finally included. This cohort had a mean age of 51.5 ± 12.1 years and an average disease duration of 4.0 ± 4.3 years. Regarding thymomas, the World Health Organization (WHO) histological classification was primarily B2 and B3 (63.7%), and Masaoka staging was predominantly IV (45.5%). Nine participants (40.9%) switched from efgartigimod to eculizumab aiming at a better clinical improvement and reducing steroid use. By week 12, the MG-ADL score decreased to 4.8 ± 4.7 (baseline: 11.7 ± 6.0), and the corticosteroid dose reduced to 23.2 ± 26.5 mg (baseline: 41.8 ± 63.9 mg). Two patients with TAMA showed significant improvement in skin lesions and thrombocytopenia. Two TEAEs were recorded including COVID-19 and herpes labialis infection. Four patients (18.2%) died of respiratory or circulatory failure owing to thymoma metastasis. Conclusion: This real-world study demonstrates the efficacy of eculizumab in achieving symptom control and corticosteroid reduction for TAMG. It may also be a therapeutic option for refractory TAMG and TAMA. Trial registration: NCT04535843. Plain language summary: Eculizumab in thymoma-associated myasthenia gravis Patients with unresectable thymomas tend to have more severe symptoms at a younger age, a higher frequency of myasthenic crisis (MC), longer respiratory support duration, and increased mortality compared to those without thymomas. Only a few case reports have explored the therapeutic efficacy of eculizumab in thymoma-associated myasthenia gravis (TAMG), which is a subtype of myasthenia gravis (MG) that is associated with anti-acetylcholine receptor antibodies. Using a multicenter, observational cohort of patients with generalized myasthenia gravis from China, we enrolled patients with TAMG who were refractory to immunotherapies and then switched to eculizumab. Our study revealed a significant improvement in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score in patients with TAMG (7.4 points) by week 12. Moreover, this study demonstrated the efficacy and safety of eculizumab in the TAMG cohort, with most patients experiencing clinical improvement within 2 weeks and an average reduction in steroid dosage of approximately one-third in the first month. Further, we believe that this article will be of interest to the readership of your journal because it provides evidence-based findings that indicate that eculizumab has emerged as a viable treatment option not only for TAMG but also for thymoma-associated multiorgan autoimmunity (TAMA). [ABSTRACT FROM AUTHOR]