New therapeutic options have recently emerged for patients with highly active, acetylcholine receptor antibody–positive (AChR-Ab+) generalized myasthenia gravis (gMG), including fast-acting, endplate-protective agents such as complement C5 inhibitors (C5-I) and neonatal Fc receptor inhibitors (FcRn-I). However, objective biomarkers beyond clinical scoring systems are lacking to guide individualized treatment decisions.

In this exploratory, prospective real-world study, we assessed serum calprotectin (sCLP) and serum neurofilament light chain (sNfL) levels in a total of 22 AChR-Ab+ gMG patients, who were treatment-naïve for either C5-I or FcRn-I. Changes in biomarker levels were correlated with clinical response, as measured by the Myasthenia Gravis–Activities of Daily Living (MG-ADL) score.

We observed a correlation of changes in sCLP and sNfl with clinical treatment response to C5-I and FcRn-I therapies. Specifically, rising levels of sNfL and sCLP were associated with a poor treatment response, as measured by the MG-ADL score.

Our preliminary findings suggest that markers of systemic inflammation (such as sCLP) and local destruction of the neuromuscular junction (such as sNfL) may assist in treatment decision-making for gMG patients. Larger, multicenter studies are warranted to validate these results and define their clinical utility.