Treatment of NMOSD
In the acute phase of clinical relapses, treatment of NMOSD is similar to that of MS, which involves immunoglobulins, steroids, or plasma exchanges. For maintenance therapy, patients may be put on corticosteroids or other forms of immunosuppressants.
Below are common maintenance therapies for NMOSD.
Corticosteroid, usually in the form of prednisolone, is the commonest maintenance therapy used for NMOSD, especially when patients are newly diagnosed following an acute attack. It is usually gradually transitioned into other forms of immunosuppressants with time, but some patients may require long term low dose corticosteroids for disease control.
Steroid-sparing Oral Agents
To minimize the side effect of corticosteroids, steroid-sparing oral agents are usually introduced as a gradual replacement. Their immunosuppressive effects usually require time to accummulate, and dosages are individualized for each patient according to body weight and disease status. Tolerance is usually good, but requires blood monitoring.
This class of agents include azathioprine, mycophenolate mofetil, and some others.
Rituximab is an anti-CD20 monoclonal antibody that has frequently been used as a maintenance therapy for NMOSD. It is an intravenous drug given at 6 to 9 month intervals depending on individual centre practice.
Satralizumab is a recombinant humanized monoclonal antibody that targets the interleukin-6 (IL-6) receptor. It is approved by the FDA (U.S. Food and Drug Administration) and licenced for treatment for NMOSD in Hong Kong. It is given subcutaneously once every 4 weeks following 3 loading doses.
Eculizumab is another humanized monoclonal antibody approved by the FDA (U.S. Food and Drug Administration) for treating NMOSD. It is given as an intravenous drug at every 2 weeks for maintenance following 5 loading doses. Although it is available in Hong Kong, it is currently not licenced for use in treating NMOSD.