FDA Clears Rystiggo as Myasthenia Gravis Treatment

Great news for those with myasthenia gravis – the FDA has approved Rystiggo, a monoclonal antibody that offers better and faster symptom relief with less discomfort during administration. 



Rystiggo’s approval is a significant breakthrough in the management of generalized myasthenia gravis (gMG), offering hope and improved quality of life for patients. This novel treatment option targets the disruption caused by autoantibodies at the neuromuscular junction, restoring communication between nerves and muscles.



Dr. Vera Bril, the lead investigator of the MycarinG study, emphasizes the drug’s quick and effective action, which will lead to better outcomes and enhanced well-being for those battling myasthenia gravis. Patients with either anti-acetylcholine receptor or anti-muscle-specific tyrosine kinase antibody-positive MG can now benefit from this targeted therapy.


Excited by the potential of Rystiggo, Dr. Rachana Gandhi Mehta highlights the importance of FcRn blockers in gMG treatment. By lowering autoantibody levels, this new therapy brings relief to patients by alleviating the burden of the disease and overcoming treatment challenges.



With the FDA’s approval, Rystiggo opens doors to a more focused approach in managing myasthenia gravis. The positive results from the MycarinG study affirm the drug’s efficacy, giving patients and healthcare providers renewed optimism for better outcomes in their battle against this debilitating condition.


Simple Daily Tasks Can Be Difficult for Those With MG.

The skeletal muscles, which link to your bones and contract to move your arms and legs as well as to breathe, become weak due to the chronic autoimmune, neuromuscular condition known as myasthenia gravis.


The Myasthenia Gravis Foundation of America estimates that 20 out of every 100,000 persons have MG, and more than 70,000 people have received a diagnosis in the United States.


According to Dr. Bril, myasthenia gravis symptoms are frequently unpredictable, incapacitating, and have a significant influence on patients’ life.


According to Mehta, the weakness connected with MG is frequently felt after physical activity and can severely restrict daily activities. Double vision and eye drooping are common symptoms that patients experience, especially after lengthy activity like reading, watching TV, driving, or using a computer. Due to the weakening in limb muscles, even routine activities like walking, climbing stairs, standing up from a seated position, taking baths, dressing, combing hair, brushing teeth, and shaving might be difficult.


Furthermore, according to Mehta, myasthenia gravis can also impair the bulbar muscles, causing problems with breathing, speaking, chewing, and swallowing.


Significant Improvements with Rystiggo

According to Bril, Rystiggo treatment led to statistically significant improvements in outcomes specific to generalized myasthenia gravis in the pivotal phase 3 trial. These included routine functions like breathing, talking, swallowing, and getting up from a chair.


On Day 43 (six weeks following the start of treatment), researchers compared the Myasthenia Gravis Activities of Daily Living (MG-ADL) total scores between the various treatment groups.


The MG-ADL scoring system evaluates one’s capacity for carrying out daily tasks; a score of 0 indicates normal function, while a score of 3 denotes a loss of that capacity. A higher score denotes a greater degree of impairment, and the total score ranges from 0 to 24, with a maximum of 24.


The results demonstrated a substantial and positive difference in the change in the MG-ADL total score from the baseline in the groups treated with two different doses of Rystiggo, with an improvement of 3.4 points at each dose compared with 0.8 points in the placebo-treated group.


In addition, a scoring system for muscle weakness revealed a statistically significant difference in Rystiggo’s favor. The dosage levels used to treat the groups were roughly 7 mg/kg (milligrams per kilogram of body weight) and 10 mg/kg, respectively. As compared to the baseline, the change in total score was -5.4 points and -6.7 points, respectively.


How Rystiggo Functions

Mehta says that Rystiggo, a humanized IgG4 monoclonal antibody that belongs to a novel family of drugs termed FcRn inhibitors, binds to the newborn Fc receptor and lowers levels of circulating immunoglobulin G (IgG), including pathogenic acetylcholine receptor (AChR) antibody.


Myasthenia gravis can be treated in a number of methods right now, but Mehta notes that many of them have severe downsides. Prednisone is an affordable oral steroid, but she points out that long-term use is linked to negative effects like weight gain, high blood pressure, and diabetes.


According to Mehta, other treatments for gMG may take many months to begin working, call for an IV infusion, or be connected to immunosuppression.


Rystiggo is injected under the skin, or subcutaneously, most frequently in the thigh or belly. Patients will be able to avoid the discomfort related to intravenous administration thanks to this, she claims.


Who Might Get the Most Benefit from Rystiggo?

“Those whose disease is not under good control and who require a quick improvement in condition may benefit from this medicine. As a bridge therapy for patients who started on immunosuppressant medicine, which might take up to a year to take effect, it may be utilized in patients with increasing disease or relapse. Rystiggo may also be beneficial for people who have not reacted to or are intolerant of the existing conventional medicines, she continues.


Safety and Side Effects of Rystiggo

Headache, infections, diarrhea, fever, hypersensitive reactions, and nausea were the most commonly reported adverse effects (occurring in at least 10% of patients).


The medical prescription for Rystiggo states that taking it could make you more susceptible to infections. 4 percent of those Rystiggo-treated in the clinical trial reported having serious infections.


Availability of Rystiggo

According to the company website, Rystiggo will be made commercially available in the United States during the third quarter of 2023 (which ends September 30), with a list price of roughly $6,050 per vial. The patient’s weight and the frequency of symptoms affect the dosage.


Depending on insurance coverage, the cost of Rystiggo will be paid out-of-pocket by the patient.

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