An Evidence-Based Review of the Mechanism of Action, Efficacy, and Safety of Biologic Therapies in the Treatment of Psoriasis and Psoriatic Arthritis

Biologic agents have expanded the repertoire of efficacious and safe systemic therapies for the treatment of moderate-to-severe psoriasis and active psoriatic arthritis. The biologics act to inhibit key inflammatory molecules that are thought to be involved in the pathogenesis of these chronic inflammatory disorders as well as physiologic immune responses. In this paper, we discuss the proposed molecular mechanisms of action, efficacy, and safety of the two FDA-approved classes of biologics, the tumor necrosis factor inhibitors and the interleukin-12/23 inhibitor. The tumor necrosis factor inhibitors that are reviewed include etanercept, infliximab, adalimumab, golimumab, and certolizumab pegol. The interleukin-12/23 inhibitor that is discussed is ustekinumab. Specifically, we review the mechanism of action for each biologic agent and the FDA-approved indications and dosing for these therapeutics. We provide up-to-date evidence for the efficacy of these systemic medications using key phase 3 clinical trial data, we highlight important safety information for each biologic based on long-term open-label extension trials and safety registries, and we discuss studies that investigate off-label dosing with the biologics. Each biologic is reviewed in these specific areas of focus for their indicated treatment of psoriasis and/or psoriatic arthritis.