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 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.