Evaluate the feasibility of using digital health technologies to monitor disease symptoms over time in individuals with gMG who are initiating treatment with VYVGART® or VYVGART Hytrulo®.

Study subjects will be screened and enrolled at Massachusetts General Brigham Hospital to participate in this 16 week observational study.

Study subjects will be asked to wear multiple wearable sensors to monitor their physical activity and PPG during daily activities. Participants will also complete speech, video, and ePRO and eCOA digital assessments at home and during study visits.

The primary objective of this observational clinical study is to remotely evaluate MG-specific outcomes using digital health technologies in individuals with gMG during two treatment cycles with VYVGART® or VYVGART Hytrulo®.

MG is a chronic autoimmune neuromuscular disease characterized by fluctuating muscle weakness that interferes with activities of daily living. Ocular, facial, swallowing, neck, limb and breathing muscles can be affected. The prevalence of MG is estimated at approximately 60,000 patients in the United States. MG symptoms are currently assessed in person through a careful history and physical exam by a neuromuscular disease expert. This is time-consuming, costly, and poses challenges in a chronic disease with fluctuating symptoms, where patients may not demonstrate any abnormality at the time of in-clinic assessment. The principal means of measuring disease severity are specific scales such as the MGC, QMG and the MG Manual Muscle Testing (MMT) scales. Although valuable, these scales are subjective and require training to administer correctly. Additionally, they provide only snapshot of a patient's disease and do not adequately reflect the spectrum of fluctuating weakness, which is a hallmark of MG. Wearable sensors and digital health technologies could enable objective, sensitive, continuous assessment of physical activity as well as motor and ocular impairments in individuals with MG.

BioSensics LLC (Newton, MA) is a medical device company specializing in wearable sensors and digital health technology for healthcare. BioSensics LLC offers a wearable sensor system and digital health solution for long-term remote monitoring of motor performance during everyday life.

This is an analytic observational study following participants over the course of 16 weeks. Subjects diagnosed with gMG who are initiating treatment with VYVGART® or VYVGART Hytrulo® will be screened and recruited to participate in this non--interventional study.

In addition to standard clinical assessments, the study will leverage BioDigit MG to remotely collect high-frequency wearable and digital health data from participants in their home environments during two treatment cycles with VYVGART® or VYVGART Hytrulo®. The frequency of at-home data collection is increased during the first 2 weeks and last 2 weeks of each treatment cycle to provide a more granular data both the initial phase (first two weeks) and the last two weeks of each treatment cycle. A key objective of the project is to measure changes in disease symptoms using both patient reported outcomes (PROs) and digital measures in individuals with gMG during the treatment cycles. The investigators will also evaluate if the combination of sensors-derived and digital measures from the BioDigit MG serves as a significant early predictor of the standard clinical outcomes.

Inclusion Criteria:

• Diagnosis of autoimmune MG with or without history of thymoma
• MGFA severity class IIa/b, IIIa/b or IVa/b at the screening visit
• Diagnosed gMG through one or more of the following:
• Positive acetylcholine receptor antibody (AChR Ab) test, or
• Abnormal neuromuscular transmission demonstrated by single-fiber electromyography (SFEMG) or repetitive nerve stimulation (RNS), or
• Documented positive response to standard MG therapies (e.g., AChE inhibitors, IVIG/PLEX, FcRn antagonists or C5 inhibitors)
• Currently initiating treatment with VYVGART® or VYVGART Hytrulo®
• Physically and cognitively able to provide informed consent and adhere to the study procedures, as determined by the investigator.
• Ambulatory, defined as the ability to walk at least 10 meters independently, with or without the use of an assistive device.
• Speaks and reads English fluently

Exclusion Criteria:

• Inability to perform essential activities of daily living required for independent living, such as dressing, bathing, toileting, or eating without assistance.
• Presence of neurological or orthopedic conditions unrelated to MG that, in the investigator's judgment, significantly impair gait or daily functioning.
• Any clinically significant medical, laboratory, or psychiatric condition that, in the opinion of the investigator, could interfere with study participation or data integrity.
• Current residence in a long-term care or institutional facility (e.g., nursing home, skilled nursing facility), receipt of hospice care, or incarceration.
• MGFA severity classification of Class I or Class V (myasthenic crisis). Pregnant or breastfeeding women.
• Concurrent participation in another interventional clinical trial (participation in observational studies, biomarker studies, or registries is permitted).

Individuals with gMG with MGFA severity class IIa/b, IIIa/b or IVa/b who are initiating treatment with VYVGART® or VYVGART Hytrulo®