Combination immunosuppressive therapies: The promise and the peril

Background: Targeted immunotherapeutic agents (TIs), also known as biological agents, are efficacious treatments for many immunologically mediated disorders, including psoriasis. In several of these diseases, including rheumatoid arthritis, Crohn's disease, and multiple sclerosis, certain TIs have been studied in combination with nonspecific immunosuppressive agents and with other TIs. Observations: Recently, the rheumatology, neurology, and gastroenterology literature has reported several examples of possible associated toxic effects when certain TIs are used in combination with other immunosuppressive agents. These toxic effects have included an increased risk of infection and malignancy. Conclusions: Combination therapies are often used by dermatologists. Several TIs have been approved for psoriasis; however, clinical trials using these drugs in combination with other immunosuppressive agents have not yet been performed. The implications for dermatologists of the toxic effects associated with TI combination therapy are unclear. However, combination therapy with certain TIs should be used with caution until more data are available.