Rituximab Biosimilar
Rituximab, is a chimeric monoclonal antibody against the
protein CD20, which is primarily found on the surface of B cells. Rituximab
is used in the treatment of many lymphomas, leukemias, and some autoimmune
disorders.
The Rituxan™ (Rituximab) antibody is a genetically engineered
chimeric murine/human monoclonal antibody directed against the CD20 antigen
found on the surface of normal and malignant B lymphocytes. The antibody is
an IgG1
kappa immunoglobulin containing murine light- and heavy-chain variable
region sequences and human constant region sequences. Rituximab is composed
of two heavy chains of 451 amino acids and two light chains of 213 amino
acids (based on cDNA analysis) and has an approximate molecular weight of
145 kDa. Rituximab has a binding affinity for the CD20 antigen of
approximately 8.0 nM. The chimeric anti-CD20 antibody is produced by
mammalian cell (Chinese hamster ovary) suspension culture in a nutrient
medium containing the antibiotic gentamicin. Gentamicin is not detectable in
the final product. The anti-CD20 antibody is purified by affinity and ion
exchange chromatography. The purification process includes specific viral
inactivation and removal procedures. Rituximab drug product is manufactured
from either bulk drug substance manufactured by Genentech, Inc. (U.S.
License No. 1048), or utilizing formulated bulk Rituximab supplied by IDEC
Pharmaceuticals Corporation (U.S. License No. 1235) under a shared
manufacturing arrangement. Rituxan is a sterile, clear, colorless,
preservative-free liquid concentrate for IV administration. Rituxan is
supplied at a concentration of 10 mg/mL in either 100 mg (10 mL) or 500 mg
(50 mL) single-use vials. The product is formulated for IV administration in
9.0 mg/mL sodium chloride, 7.35 mg/mL sodium citrate dihydrate, 0.7 mg/mL
polysorbate 80, and sterile water for injection. The pH is adjusted to 6.5.
