Dual IL-17A/F Blockade Increases Candidiasis Risk in Patients

A recent study presented at the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) 2025 Annual Meeting in Bogotá, Colombia, has unveiled critical insights into the heightened risk of candidiasis associated with dual blockade of interleukin (IL)-17A and IL-17F. The research indicates that drugs such as bimekizumab, which target both IL-17A and IL-17F, significantly impair the ability of neutrophils—key white blood cells—to combat fungal infections, thereby increasing susceptibility to mucosal and systemic candidiasis.

The study, led by Disha Chakraborty, a postdoctoral fellow in the Division of Rheumatology & Immunology at the Veterans Affairs Medical Center in Mather, California, involved blood samples from ten patients diagnosed with psoriatic arthritis. This research employed chemotaxis assays to analyze neutrophil migration in response to various cytokine combinations. The findings revealed that when both IL-17A and IL-17F were present, neutrophil chemotaxis was markedly diminished compared to when either cytokine was administered alone. This reduction in neutrophil function was associated with an increased survival rate of Candida cells, suggesting a synergistic effect of the dual blockade.

According to Dr. Chakraborty, "Clinical trials and post-marketing surveillance of bimekizumab indicated a rise in candidiasis cases. Our hypothesis that neutrophil chemotaxis impairment contributed to this trend was substantiated by our experimental results. However, it is essential to consider that bimekizumab demonstrates substantial efficacy in treating psoriatic arthritis, necessitating a balance between effective treatment and vigilant patient monitoring."

The implications of this study are significant, particularly as the incidence of candidiasis continues to rise globally, a trend previously underscored by the World Health Organization (WHO). The dual blockade of IL-17A and IL-17F may be particularly relevant in populations already at risk for fungal infections, such as those with compromised immune systems.

Experts in the field have expressed varying perspectives on the findings. Dr. Sarah Johnson, a Professor of Immunology at Stanford University, commented, "This research adds an important layer to our understanding of how immunomodulatory therapies can inadvertently facilitate opportunistic infections. Clinicians must be acutely aware of these risks when prescribing IL-17 blockers."

Moreover, Dr. Mark Thompson, a leading researcher in fungal infections at Johns Hopkins University, emphasized the need for comprehensive monitoring protocols for patients receiving IL-17A/F blockade therapies. He stated, "As we explore the therapeutic benefits of new drugs, it is vital to remain vigilant about their potential adverse effects, particularly in susceptible populations."

The study, while shedding light on the risks associated with dual IL-17 blockade, is not without limitations. The small sample size raises questions about the generalizability of the findings, and additional research is warranted to explore the clinical implications fully. Moreover, while the data indicates a clear link between the dual blockade and increased candidiasis risk, further studies are necessary to understand the mechanisms at play and to develop targeted strategies that mitigate these risks.

As bimekizumab continues to be integrated into clinical practice for treating psoriatic arthritis, clinicians must weigh its benefits against the potential for increased infection risks. Future research will be crucial in establishing guidelines for the safe use of IL-17A/F blockers and ensuring patient safety amidst evolving treatment landscapes.