Myasthenia gravis (MG) is a favorite condition for neuromuscular physicians to consider. It is usually easy to recognize in the clinic, straightforward to diagnose in the lab, and is often highly responsive to treatments that are familiar to neurologists. Recently, novel immunotherapies for cancer have spawned a new breed of autoimmune neuromuscular disorders, including myasthenia gravis, often in combination with other autoimmune conditions such as myositis. Idiopathic, thymoma-associated, and immune checkpoint inhibitor-induced MG may be refractory to conventional treatments and require emerging therapies. In this virtual issue, topics from diagnosis to novel treatments and outcome measures are considered.

At onset, MG can rapidly progress to respiratory failure and, as serology results are not available immediately, confirmation of the clinical diagnosis must be accomplished by other means. Oh et al. review their experience with repetitive stimulation testing in MG crisis, showing that nearly 10% of such patients have normal testing. Once diagnosed, preventing MG exacerbations are a chief treatment goal, and the work of Gummi et al provides further evidence that vaccinations are safe and that infections and medication changes underlie most exacerbations. Exacerbations that are attributed to the fluctuating nature of MG cannot be predicted by following a patient’s acetylcholine receptor antibody level but, for MG patients with muscle-specific kinase antibodies (MuSK), the report by Triplett et al. suggests that MuSK antibody levels may predict exacerbations allowing for pro-active treatment. Gras-Champel et al. show that statin administration is only tenuously associated with MG and that the cardiovascular benefits outweigh any risks of developing MG.

Recently, new treatments that target specific elements of the immune system have been used to treat the most resistant and severe cases of MG. Muppidi et al. present work from a consortium demonstrating the long-term safety and efficacy of a membrane attack complex inhibitor, eculizumab, to treat MG. Waters et al. present a case of MG responding to ofatumumab, a monoclonal antibody to the B-cell CD20 epitope. Other emerging immunotherapies are excellently reviewed by Farmakidis et al. While thymectomy is an effective treatment for generalized MG with acetylcholine receptor antibodies, the work of Clifford et al. buttresses the evidence that thymectomy is not helpful in MG with MuSK antibodies.

These new therapies are often more complex to deliver, have unique adverse events, and are extremely expensive, so it is imperative that clinical trials are optimally performed. Works from Salci et al. and Vinge et al. show that timed walk testing and isometric dynamometry could be used as outcome measures in clinical trials. Data analyzed by Frisaldi et al. reassuringly show that the placebo response of the quantitative MG score used in MG clinical trials is clearly smaller than treatment responses.

We hope you enjoy reading this collection of timely articles.

Zachary Simmons, MD, Editor-in-Chief, Muscle & Nerve

James B Caress, MD, Associate Editor, Muscle & Nerve