What biologics are currently available to inhibit TNF α?
ETN (Enbrel): a bioengineered molecule derived from Chinese hamster ovary cells, which consist of a fusion protein created by linking the extracellular binding regions from two TNF-RII (p75) receptors to the Fc portion of human immunoglobulin G1 (IgG1). This molecule is a dimeric soluble TNF receptor that binds soluble TNF-α and lymphotoxin (TNF-β). Its half-life is 3 to 5 days.
INF (Remicade): chimeric mouse–human monoclonal antibody composed of the constant regions of human IgG1 heavy and partial kappa light-chain domains coupled to the variable region of a mouse light chain with high affinity for human TNF-α. INF binds both soluble and cell-bound TNF-α and thus has the ability to induce apoptosis of cells with TNF-α bound to its surface. It does not bind lymphotoxin (TNF-β). Its half-life is 8 to 9 days. Concomitant use of MTX increases the amount of INF exposure by 30%.
ADA (Humira): fully human IgG1κ monoclonal antibody that binds soluble and transmembrane forms of TNF-α. Its half-life is 10 to 13 days. Simultaneous use of MTX increases a patient’s exposure to ADA by 30%.
Golimumab (Simponi): fully human IgG1κ monoclonal antibody that binds soluble and transmembrane forms of TNF-α. Median half-life is 14 days. Concomitant MTX use increases trough concentrations of golimumab by 30%.
Certolizumab pegol (Cimzia): Fab fragment of a recombinant, humanized anti-TNF monoclonal antibody that has been fused to a polyethylene glycol moiety. Cannot bind to Fc receptors, fix complement, or cross placenta due to not having a functional Fc fragment. Its half-life is 14 days. The pegylation delays clearance and may help localize the molecule to acidic, inflammatory sites.
