The effect of neutralizing antibodies on the sustainable efficacy of biologic therapies: what's in it for African and Middle Eastern rheumatologists.

Over the last decade, biologic therapeutic proteins have advanced the treatment of diseases such as rheumatoid arthritis (RA). Therapeutic antibodies such as infliximab, adalimumab, rituximab, tocilizumab, golimumab, certolizumab pegol, the receptor construct etanercept, and abatacept, an anticluster of differentiation (CD)80/anti-CD86 fusion protein, are used as treatment for RA and ankylosing spondylitis (AS). Infliximab, adalimumab, golimumab, certolizumab pegol, and etanercept are inhibitors of tumor necrosis factor (TNF), a key regulator of inflammation. Left untreated, progression of rheumatic diseases due to inflammation can lead to irreversible joint damage and serious disability. One limitation for the use of therapeutic antibodies is immunogenicity, the induction of antibodies by the adaptive immune system in response to foreign substances. The development of antidrug antibodies (ADAs) has a varying impact on the clinical efficacy of biologic agents for the treatment of RA and AS, depending on whether the ADAs are neutralizing or non-neutralizing. Studies have indicated that neutralizing ADAs are associated with a reduced efficacy, decreased drug survival, increased instances of dose escalation, and adverse events. Comparison studies of anti-TNF biologics have demonstrated that each drug has a different sustained efficacy profile depending on immunogenicity. The purpose of this review is to provide rheumatologists with information regarding the effect of neutralizing antibodies on the sustainable efficacy of anti-TNF biologic therapies. This information will be of value to practicing rheumatologists in Africa and the Middle East who should take into account the potential for changes in the efficacy and safety of biologic therapies and closely monitor patients under their care.