Biologic therapies are advanced medications that target specific parts of the immune system involved in inflammation. Rather than suppressing the immune system broadly, biologics are designed to block or reduce the activity of specific immune cells or proteins that contribute to disease. In myositis, biologic therapies are typically considered for patients with refractory disease, significant organ involvement, or inadequate response to conventional immunosuppressive medications.

Rituximab (Rituxan)

Rituximab is a biologic therapy that targets CD20-positive B cells, a type of immune cell involved in autoimmune disease. By reducing the number of circulating B cells, rituximab helps decrease the immune system activity that contributes to inflammation and tissue damage. It is commonly used in patients with refractory dermatomyositis, polymyositis, antisynthetase syndrome, immune-mediated necrotizing myopathy (IMNM), and myositis-associated interstitial lung disease (ILD). Although it is not FDA-approved specifically for myositis, it is one of the most frequently used biologic therapies for patients who have not responded adequately to other treatments.

How it is administered

  • Given by intravenous (IV) infusion in a healthcare setting
  • Treatment is typically administered as a series of infusions, with repeat courses based on disease activity and physician recommendation

Common side effects

  • Infusion reactions, including fever, chills, rash, or headache
  • Fatigue
  • Upper respiratory infections
  • Nausea

Important considerations

  • Because rituximab suppresses B cells, it may increase the risk of infections
  • Patients are often screened for hepatitis B before treatment
  • Vaccinations should be discussed with a healthcare provider before starting therapy

Abatacept (Orencia)

Abatacept works by interfering with T-cell activation, an important step in the immune response that drives inflammation in autoimmune diseases. By reducing T-cell activity, abatacept may help decrease muscle and systemic inflammation. It has been studied in dermatomyositis and polymyositis and may be considered in selected patients with difficult-to-treat disease. While research has shown potential benefit in some patients, abatacept is not currently approved specifically for myositis.

How it is administered

  • Given either as an intravenous (IV) infusion or as a subcutaneous (under-the-skin) injection

Common side effects

  • Headache
  • Nausea
  • Upper respiratory infections
  • Injection-site reactions

Important considerations

  • May increase susceptibility to infections
  • Patients should notify their healthcare provider if they develop signs of infection, including fever or persistent cough
  • Regular monitoring may be recommended during treatment

Tocilizumab (Actemra)

Tocilizumab is a biologic therapy that blocks interleukin-6 (IL-6), an inflammatory protein involved in immune system signaling. It has been studied in patients with refractory myositis and myositis-associated ILD. Although clinical trial results have been mixed, some physicians may consider tocilizumab for selected patients whose disease has not responded to more commonly used treatments.

How it is administered

  • Available as an intravenous (IV) infusion or subcutaneous injection

Common side effects

  • Upper respiratory infections
  • Headache
  • Elevated liver enzymes
  • Increased cholesterol levels
  • Injection-site reactions

Important considerations

  • Regular blood tests may be needed to monitor liver function, blood counts, and cholesterol levels
  • Patients should promptly report signs of infection
  • Live vaccines are generally avoided during treatment

Disclaimer: Information provided on this website is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with any questions you may have regarding a medical condition.