Pharmaceutical aspects of anti-inflammatory TNF-blocking drugs

Tumor necrosis factor (TNF) is a key regulator of inflammatory processes in several immune-mediated inflammatory diseases such as rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, ulcerative colitis, psoriasis and psoriatic arthritis. Inactivating TNF has been found to be a plausible approach in treating these conditions. Two major strategies have been adopted by scientists to inactivate TNF: one is to use monoclonal antibodies (mAbs) that bind to TNF, and the other is to use fusion proteins that bind to TNF, both inactivate TNF and help to prevent TNF-mediated inflammatory processes. Monoclonal antibodies (mAbs) are biological products that selectively bind to specific antigen molecules, and fusion proteins are soluble receptors that bind to TNF. These types of drugs are generally known as biologics and there has been an explosion in the development and testing of biologics since the 1994 US approval and launch of abciximab, a mAb that binds to GPIIb/IIIa on platelets. Anti-TNF drugs that are currently approved by FDA for treating inflammatory conditions include adalimumab, certolizumab pegol, golimumab, infliximab and etanercept. Since these agents are complex protein molecules, the pharmacodynamics and pharmacokinetics of these drugs are different from small-molecule anti-inflammatory agents. This review focuses on the pharmaceutical aspects of these drugs such as mechanism of action, adverse effects, pharmacokinetics and drug interactions. An effort was also taken to compare the pharmacodynamics and pharmacokinetic properties of these drugs, with the available data at this time.