Rystiggo

Pharmaceutical company: UCB Pharma

To move, signals must be sent from the brain, down specialised cells called nerves to the muscle. Acetylcholine receptors and a protein called MuSK play a key role in passing the signal from nerve cells to the muscle. In myasthenia gravis, the immune system attacks the acetylcholine receptors, and in a smaller percentage of cases, the MuSK protein. This means the nerve cells struggle to send strong signals to muscles, leading to muscle weakness.

Rystiggo works by reducing the effect of the immune system on the acetylcholine receptors and MuSK protein. Specifically, Rystiggo reduces the levels of molecules called antibodies. Antibodies are produced by the immune system to protect the body from foreign substances, like bacteria. However, sometimes these antibodies can target our own cells. By reducing the levels of the antibodies, stronger signals should be able to be sent to the muscles.

Rystiggo come as a liquid and is administered slowly under the skin (subcutaneous infusion).

Rystiggo is approved for NHS use in England, Wales and Northern Ireland.

In Scotland, Rystiggo may be available through an early access scheme. For more information, please get in touch with your clinician.

In April 2026, Rystiggo was accepted for NHS use in England, Wales and Northern Ireland for those with refractory myasthenia gravis.

If you are struggling to access Rystiggo, please contact us on campaigns@musculardystrophyuk.org.

There currently isn’t a timeline for the assessment by the Scottish Medicines Consortium (SMC) for use on the NHS in Scotland.

We are proud to have played a key role in making sure Rystiggo is available for people with myasthenia gravis. Working in partnership with the charity myaware, we made sure the experience and views of the myastheia community were heard.

Rystiggo was tested in the phase 3 MycarinG trial. 200 participants, aged over 18 years old, with a myasthenia gravis activities of daily living (MG-ADL) score of at least three took part in the trial. The MG-ADL score measures the impact of the condition on a person’s daily function, such as talking, swallowing and getting up from a chair. The score can range from zero to 24, with a lower score means symptoms are less severe.

Participants were randomly assigned to receive one of two doses of Rystiggo (133 participants) or placebo (dummy drug, 67 participants). All participants tested positive for the antibodies which attack acetylcholine receptors or MuSK protein. Rystiggo was found to be safe. After 43 days, more participants who received Rystiggo showed improvements in the MG-ADL scale, compared to those who received the placebo.

68% of participants who received Rystiggo had a reduction of at least two points, compared to 28% of participants who received the placebo. A reduction of two points is considered to be beneficial (clinically meaningful) to people living with the condition. This may mean people with the condition are able to complete daily tasks they were unable to before, such as brush their hair or get up out of a chair without assistance.

Last updated: 05/05/2026