Rituximab

Description

Rituximab, a chimeric murine/human monoclonal antibody approved in the United States only for treating refractory or relapsed B-cell lymphomas, reacts with the CD20 antigen. It contains the complementarity determining murine anti-CD20 antibody 2B8 regions in conjunction with human kappa and IgG1 heavy-chain constant region sequences. The vector was cloned into Chinese hamster ovarian cells as the production source of immunoglobulin. Rituximab is composed of two heavy chains of 451 amino acids and two light chains of 213 amino acids with a molecular weight of 145 kD. Rituximab has a binding affinity for the CD20 antigen of approximately 8.0 nM, similar to the parent murine antibody, 2B8[1].

Uses

Antineoplastic (microtubule inhibitor); monoclonal antibody.

Uses

Rituximab is being used for Coronavirus-related infections.

brand name

Rituxan (IDEC).

Mechanism of action

Rituximab has a unique mode of action and can induce the killing of CD20+ cells via multiple mechanisms. The direct effects of rituximab include complement-mediated cytotoxicity and antibody-dependent cell-mediated cytotoxicity, and the indirect effects include structural changes, apoptosis, and sensitization of cancer cells to chemotherapy.

Clinical Use

Rituximab has seen use in transplant patients in several settings: (1) treatment of post-transplant lymphoproliferative disease (PTLD); (2) prevention of rejection; (3) ABO-incompatible transplantation; (4) treatment of rejection; (5) desensitization in HLA sensitized patients. The treatment of post-transplant lymphoproliferative disease has probably seen the greatest use of rituximab with great success. However, there is no formal indication of this use. In non-transplant patients with lymphoma, rituximab is typically combined with other chemotherapeutic agents with somewhat worse results.