Actemra/RoActemra (tocilizumab) is a humanized IgG1 antibody targeted against the IL-6 receptor (IL-6R), and it is approved for use in cases of rheumatoid arthritis (RA); generally where other treatments have proven unsuccessful. It is also widely used in the management of systemic juvenile idiopathic arthritis, and Japan has approved Actemra for use in the treatment of Castleman’s disease.
Target Antigen: IL-6
IL-6 is a cytokine that is involved in the development of the body’s inflammatory and immunological reactions, and as such is implicated in the pathogenesis of many diseases. Abnormally high levels of IL-6 are observed in autoimmune diseases such as rheumatoid arthritis: Actemra/RoActemra (tocilizumab) is effective in the treatment of RA by binding to both soluble and membrane-bound IL-6 receptors preventing IL-6 from binding.
Characterization of Tocilizumab Innovator and Biosimilar Products
The IL-6 signalling system is compelling because although IL-6R specifically binds IL-6, it does not directly transduce a signal. Instead, IL-6 binds to IL-6R on the cell membrane, and forms a complex with the trans-membrane glycoprotein, gp130. Once in this trimeric form, gp130 forms a disulphide-linked homodimer with another gp130 protein to initiate intracellular signal transduction via the JAK/STAT pathway – this is known as the classical signalling pathway. However, IL-6 also has a secondary pathway, the trans signalling pathway, which doesn’t require IL-6R to be localized to the cell membrane: soluble IL-6R, which can be present at relatively high levels in the circulation of even healthy individuals, can also bind IL-6. This soluble IL-6/IL-6R complex can associate with cell associated gp130 resulting in signal transduction. Actemra (tocilizumab) not only prevents formation of the IL-6/IL-6R complex and subsequent signalling via both classical and trans pathways, but it can also disrupt IL-6/IL-6R complexes that are already formed, and thus has the potential to exert an extremely robust blocking action on IL-6 signalling by a number of different mechanisms.
BioOutsource provides an integrated package of methods for biosimilar characterization and comparability. Our integrated package includes off-the-shelf binding assays, bioassays and physicochemical and structural characterization to reduce development timelines. In addition to our suite of analytical testing for tocilizumab products, we offer a broad range of testing and development services for all monoclonal antibodies:
- Actemra Binding Assays
- Actemra Bioassays
- Actemra Physicochemical and Structural Assays
- Cell Bank Manufacturing
- Biosafety Testing for Monoclonal Antibodies
Our experts are continuously adding to our range of off-the-shelf assays and platform methods to support the testing of Actemra biosimilars. If you require a method that is not mentioned please contact our experts to discuss.