[pubmed] Rituximab in Myasthenia Gravis - Where do we stand?

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Expert Opin Biol Ther. 2021 Feb 10. doi: 10.1080/14712598.2021.1889509. Online ahead of print.

ABSTRACT

INTRODUCTION: Myasthenia gravis (MG) is an antibody-mediated disease with diverse serology and clinical presentation. Currently, MG is managed with untargeted immunomodulatory agents. About 20% patients are refractory to these therapies. A number of novel and targeted treatments are on the horizon. Several studies in MG report efficacy of Rituximab, a monoclonal antibody, particularly in patients with antibody against muscle-specific kinase or refractory disease.

However, a recent trial showed negative results. Compared to conventional oral immunosuppressive therapies, Rituximab has a rapid onset of action, sustained benefit, and convenient dosing. Regular hematological monitoring is not required though serious side effects can occur. Current status of Rituximab in MG and newer immunosuppressant are discussed.

AREAS EXPLORED: Biologic features, clinical effectiveness, safety profile and newer preparations of Rituximab.

EXPERT OPINION: Rituximab provides a promising option in the management of MG, particularly in patients with muscle-specific kinase antibodies or those with refractory disease. Several knowledge gaps remain as there is a scarcity of data from controlled studies due to difficulties in conducting large clinical trials in a rare disease. Larger, well designed studies are needed to assess the comparative efficacy to Rituximab to conventional immunosuppressant agents, and its overall place and optimal regimen in MG.

Multiple novel immunosuppressive therapies with targeted mechanisms of action are on the horizon for Myasthenia Gravis (MG).

Rituximab is a monoclonal antibody that depletes B cells and (certain populations of T cells) thereby reducing formation of plasma cells and disease causing antibodies.

Several uncontrolled studies show Rituximab to be safe and effective in MG, particularly in anti-MuSK and refractory MG.

A phase 2 RCT controlled trial did not show any significant difference between the steroid sparing effect of Rituximab and placebo. Drawbacks in this trial design and predominant inclusion of patients with mild disease make if difficult to interpret its results.

With availability of cheaper biosimilars and subcutaneous formulations of Rituximab, its off label usage in MG is likely to increase.

Data from larger controlled studies will be needed for regulatory approval of Rituximab in MG.

PMID:33566716 | DOI:10.1080/14712598.2021.1889509


Source: https://pubmed.ncbi.nlm.nih.gov/3356671 ... 6&v=2.14.2