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.

Objective: This study aimed to explore the relationship between systemic inflammation markers and clinical activity, respiratory failure, and prognosis in patients with myasthenia gravis (MG).Methods: One hundred and seventeen MG patients and 120 controls were enrolled in this study. Differences in the four immune‐related markers of two groups based on blood cell counts: neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), lymphocyte to monocyte ratio (LMR), and systemic immune‐inflammation index (SII) were measured. The stability of the associations between systemic inflammation markers and respiratory failure in MG patients was confirmed by adjusted logistic regression analysis. Moreover, Kaplan–Meier curve and multivariate COX regression models were applied to assess the factors affecting the outcome of MG.Results: NLR, PLR, and SII were higher in MG patients than those in controls and were positively associated with MGFA classification, but not LMR. Adjusted logistic regression analysis showed that PLR was an independent predictor of MG with respiratory failure. The ROC curve demonstrated that PLR showed good sensitivity and specificity for the diagnosis of MG with respiratory failure. Kaplan–Meier curve showed that GMG, positive AchR‐Ab, respiratory failure, high NLR, PLR, SII, and IVIg exposure correlated with the risk for poor outcomes in MG patients. The multivariate COX regression models indicated that GMG and high SII was a risk factor for poor outcome of MG.Interpretation: The systemic inflammation markers expressed abnormally in MG patients, in which PLR may be an independent predictor of respiratory failure, and high SII and GMG were predictive risk factors for poor outcomes in MG patients.

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.