Rituximab for Myositis

How does Rituximab work?

In myositis, one group of immune cells called B-cells can produce harmful antibodies and help drive inflammation in the muscles, skin, and other organs.

Rituximab works like a targeted treatment that specifically finds and removes these B-cells from the circulation.

• Removes the B-cells contributing to inflammation
• Reduces the production of harmful antibodies
• Helps calm the immune system
• Allows the body to gradually rebuild a healthier population of B-cells over time

Will Rituximab completely suppress my immune system?

No. Rituximab mainly targets B-cells, while many other parts of the immune system continue to function normally. However, the risk of infections may still increase slightly, which is why regular monitoring is important.

Rituximab also does not permanently remove B-cells. Most patients gradually regrow B-cells over 6–12 months, although the timing varies. Repeat infusions may sometimes be required depending on the response to the first infusion.

Uses

• Myositis
• Rheumatoid arthritis
• Systemic lupus erythematosus (SLE)
• Vasculitis
• Certain blood disorders and immune conditions

How is Rituximab given?

Rituximab is given as an intravenous (IV) infusion in a hospital or infusion centre. A typical treatment course may involve two infusions given 2 weeks apart, or 4 infusions given 1 week apart.

Depending on your condition, repeat treatment may be required every 6–12 months, although the schedule varies between patients.

Why do I need infection screening before Rituximab?

Doctors routinely screen for certain infections before treatment. This may include hepatitis B, hepatitis C, and tuberculosis (TB) screening.

Why do I need pre-medications before the infusion?

Before each infusion, you will usually receive paracetamol, an antihistamine (anti-allergy medicine), and a steroid medication. These help reduce chills, fever, itching, throat irritation, and skin rash. Most infusion reactions, if they occur, are mild and can be managed by slowing the infusion rate.

Common side effects

Most people tolerate Rituximab very well. Common side effects include fatigue for a day or two after the infusion, mild headache, mild infusion reactions, and temporary throat irritation or itching during the drip.

Why are blood tests necessary?

Rituximab can occasionally affect blood counts, protective antibody levels (immunoglobulins), and the body's ability to control certain hidden infections.

• Complete blood count (CBC)
• Immunoglobulin levels (IgG, IgA, IgM)
• Liver function tests (occasionally)
• Infection screening before treatment

During infection

Contact your healthcare team if you develop high fever, a significant infection, or hospital admission. To help prevent infections, each patient on Rituximab is given prophylactic antibiotics to be taken for 3–6 months after Rituximab infusion.

Pregnancy and vaccines

Pregnancy should be avoided during treatment and for several months after receiving Rituximab.

Because Rituximab removes the cells that help create vaccine responses, some vaccines may not work as well after treatment. Ideally, important vaccines should be given before Rituximab whenever possible. Annual flu and pneumococcal vaccination may be recommended. Live vaccines should usually be avoided.