In this episode of Topical Conversations, Brad Glick, DO, and Jason Hawkes, MD, discuss the use of IL-17 inhibitors in managing psoriasis and psoriatic arthritis, with a focus on ixekizumab. Their conversation highlights the immunologic basis of IL-17, the safety and efficacy of ixekizumab, and its role in addressing the complex interplay of skin and joint symptoms in psoriatic disease. 

The role of IL-17 in psoriasis 

They begin by explaining that IL-17 plays a dual role in skin health. It provides natural protection against infections like candidiasis; however, excessive levels of IL-17 can drive keratinocyte hyperproliferation, leading to the scaling and plaque formation characteristic of psoriasis. 

Ixekizumab, by targeting IL-17A, helps normalize keratinocyte activity and significantly improves psoriasis symptoms. This mechanism of action also explains why some patients develop candidiasis during treatment, as blocking IL-17 reduces natural defenses against infections like candidiasis. 

Managing safety concerns 

While ixekizumab does not cause inflammatory bowel disease (IBD), it can exacerbate symptoms in patients with preexisting IBD. For patients who present with both psoriasis and IBD, clinicians need to carefully weigh the benefits of improved skin symptoms against the potential for worsening gastrointestinal issues. Monitoring and patient education are essential to ensure that risks are understood and managed effectively. 

Candidiasis, a known side effect of IL-17 inhibition, also requires consideration. By understanding the underlying immunologic mechanisms, dermatologists can counsel patients appropriately and address concerns about this potential complication. 

Efficacy of ixekizumab in psoriasis 

Clinical trials, including the UNCOVER studies, have demonstrated ixekizumab’s high efficacy in psoriasis treatment. The trials revealed significant rates of disease clearance, with about half of patients achieving PASI 100. These outcomes represent a substantial improvement over earlier treatments like methotrexate and TNF inhibitors. 

However, patient characteristics such as body weight can influence outcomes. For patients with higher body weights, efficacy may decrease, potentially due to the pro-inflammatory effects of adipose tissue. These findings highlight the importance of tailoring treatment approaches to individual patient profiles. 

Ixekizumab and psoriatic arthritis 

Psoriatic arthritis (PsA), a common comorbidity of psoriasis, remains challenging to treat. While ixekizumab and other IL-17 inhibitors have shown moderate efficacy in managing joint symptoms, they are highly effective for skin improvement. Dermatologists must set realistic expectations with patients, explaining that while dramatic skin improvements are likely, joint symptoms may respond more slowly or to a lesser degree. 

Exploring future approaches 

Emerging research is investigating the potential synergy of IL-17 inhibitors with GLP-1 receptor agonists. This approach aims to address systemic inflammation associated with obesity, which is linked to higher risks of diabetes, cardiovascular disease, and poorer psoriasis outcomes. By targeting both psoriasis and metabolic health, this strategy could offer comprehensive benefits, though further studies are needed to clarify its impact. 

Key takeaways for dermatologists 

Ixekizumab represents a significant advancement in psoriasis treatment, due to its high efficacy and targeted action. While considerations such as candidiasis risk and IBD management are important, this IL-17 inhibitor remains a strong option for dermatologists, with its potential for future innovations further underscoring its value in advancing patient care.