Combination Biologic Treatment of Refractory Psoriasis and Psoriatic Arthritis

To the Editor: The pathophysiology of psoriasis and psoriatic arthritis (PsA) is dependent on a multistep process that leads to chronic or recurrent inflammation1,2,3. Blockade of cytokines, receptors, and coreceptors represents one approach to treating these diseases, but a significant number of patients have a recurrent course or a persistent disease process. A persistent process appears to suggest that blockade of individual inflammatory mediators is not enough to control the disease. On the other hand, among the patients who do respond to disease-modifying antirheumatic drugs (DMARD), the doses needed to control the disease sometimes are too high and may lead to severe adverse reactions. A different or complementary approach to conventional therapy is to use combination therapy that simultaneously targets different pathogenic mechanisms of the disease pathophysiology. The rationale of using a combination of biologic agents is based upon the complex pathogenic mechanisms involved in the disease process, in which Th1 and Th17 cells play major roles. It has been shown that keratinocytes and dendritic cells in psoriatic skin overproduce interleukin 23 (IL-23), which is one of the cytokines that regulates the Th17 cells, and IL-22 induces keratinocyte proliferation. In addition, clinical data show that tumor necrosis factor-α (TNF-α) inhibitors reduce epidermal hyperplasia as well as synovitis/enthesitis by decreasing Th1 and Th17 cell responses1. The literature on combination biologic therapy for patients with autoimmune diseases is sparse, probably because the majority of cases are well controlled with 1 biologic agent alone or in combination with classic DMARD, and safety issues and adverse events are major concerns. We describe a patient with psoriasis and PsA refractory to standard treatment with DMARD alone or in combination with biological therapy. The patient responded to the combination of 2 biologic agents given concomitantly. A 38-year-old white … Address correspondence to Dr. Espinoza; E-mail: lespin1{at}lsuhsc.edu