Myasthenia Gravis, MuSK

This Phase 2 proof-of-concept, dose range finding study aims to evaluate the safety and efficacy of 3 dose levels of NMD670 vs placebo in adult patients with MG with antibodies against AChR or MuSK, administered twice a day (BID) for 21 days.

The goal of the AXIS Autoimmune Neurology Registry is to learn about the experiences of adults living with autoimmune neurological disorders, starting with myasthenia gravis (MG), over time. The main questions the registry aims to answer are: * How do symptoms, daily functioning, and quality of life change over time? * What treatments do participants use, and how are these treatments related to their symptoms and health? * What challenges do participants experience with treatment, including side effects, treatment burden, missed doses, and access to care? Participants will: * Join the registry and complete an enrollment survey (online or through a mobile app) * Complete a brief online survey about their MG approximately once a month * Provide information that can help confirm their MG diagnosis * Optionally, share their medical records with the research team This is an observational study. The registry will not assign treatments or ask participants to change their medical care. Information collected through the registry may help researchers better understand MG and improve future research and care.

The goal of this observational study is to learn about the experiences of people living with Myasthenia Gravis (MG) in the United States. The main questions it aims to answer are: * How and when are people with MG diagnosed? * What are the most common symptoms associated with MG? * What treatments are being used to treat MG? * What are the impacts of MG on activities of daily living, employment and quality of life? * What are the experiences with exacerbation, hospitalization and healthcare access for people with MG? Participants will answer a survey to enroll in the study, and be invited to fill out an update survey twice a year.