Efgartigimod non-responders after the first treatment cycle in generalized myasthenia gravis: a retrospective analysis of predictive factors

TL;DR

This study identifies factors that predict poor response to efgartigimod in patients with generalized myasthenia gravis.

Contribution

The study provides predictive factors for suboptimal response to efgartigimod in gMG patients using clinical and serological data.

Findings

Non-responders had higher baseline gross motor and respiratory sub-scores.

Thymoma, tumors, thyroid disease, and autoimmune disorders were more common in non-responders.

Combinations of these factors predicted poor response with up to 97.9% probability.

Abstract

This study aimed to identify predictors of suboptimal response to efgartigimod in patients with generalized myasthenia gravis (gMG).

In this single-center retrospective study, 35 gMG patients treated with efgartigimod were categorized into responders (n = 25) and non-responders (n = 10). Responders were defined by a reduction of >2 points in MG-ADL or >3 points in QMG score after one cycle, whereas non-responders showed improvement below these thresholds and subsequently responded to eculizumab. Demographic, clinical, and serological features were compared using univariate and multivariate analyses.

Non-responders had higher baseline gross motor and respiratory sub-scores. Univariate analysis revealed that thymoma, non-thymoma tumors, thyroid disease, and other autoimmune diseases were more common in non-responders. Multivariate analysis indicated that combinations of these factors were associated with a high predicted probability of poor response (up to 97.9%).

Comorbidities including thymoma, other tumors, thyroid disease, and additional autoimmune disorders may predict reduced response to efgartigimod in gMG patients. Systematic evaluation of these factors could help optimize treatment selection.

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