Biological agents are used to treat a variety of diseases in many therapeutic areas, including oncology, rheumatology, gastroenterology, dermatology, respiratory disease, hormone deficiency and infection. While biologics constitute many of the recently approved new therapies, clinical research of drug-drug interactions with biologics has been scant. This review presents a risk-based assessment strategy for evaluating drug-drug interactions with monoclonal antibodies, a predominant class of therapeutic biologics. The key parameters of this strategy are described here, as well as suggested studies that should be considered as part of the overall drug development process for therapeutic biologics.