This review discusses the rationale behind recommending immunopharmacological guidance of long-term therapies with anti-TNF-α specific biotherapies. "Arguments why therapeutic decision-making should not rely on clinical outcomes alone are presented. Central to this is that the use of theranostics (i.e., monitoring circulating levels of functional anti-TNF-α drugs and antidrug antibodies) would markedly improve treatment because therapies can be tailored to individual patients and provide more effective and economical long-term clinical benefits while minimising risk of side effects. Large-scale immunopharmacological knowledge of the pharmacokinetics of TNF-α biopharmaceuticals in individual patients would also help industry to develop more effective and safer TNF-α inhibitors" [1].