Data with respect to safety and therapeutic efficacy for the combination of biological DMARDs is scarce and inhomogeneous in order to make final conclusions. To this end, data to biologic combinations is disappointing due to relatively low therapeutic efficacy and partially enhanced rates of severe infectious events.
Combining biologics is an option only in very special situations (RTX plus TNFi). In addition, the relation of financial effort to therapeutic efficacy is questionable, especially in the situation of numerous drug options (anti-cytokine principle, T-cell inhibition, B-cell depletion) and therapeutic strategies of combining biologics with DMARDs. Generally speaking, combinations of biological should only be used in clinical trials. New drugs influencing intracellular signaling pathways (small molecules) are going to be approved or are already approved by the drug agencies, thus, adding to the existing armamentarium. Furthermore, combinations with these new molecules are going to be interesting.
This review summarizes the available studies concerning combination of biologicals in a tabular fashion.