How Cosentyx Works and Its Link to Infections
Cosentyx (secukinumab) is a monoclonal antibody that targets interleukin-17A (IL-17A), a cytokine central to the immune system's inflammatory response. By binding and neutralizing IL-17A, it reduces inflammation in conditions like psoriasis, psoriatic arthritis, and ankylosing spondylitis. This mechanism disrupts the Th17 pathway, which recruits neutrophils and promotes antimicrobial peptides at epithelial barriers, such as skin and mucosal surfaces.[1]
Why It Raises Local Infection Risk
Locally, the risk stems from impaired barrier immunity. IL-17A strengthens skin and mucosal defenses by:
- Boosting production of antimicrobial peptides (e.g., defensins, cathelicidins) from keratinocytes and epithelial cells.
- Enhancing neutrophil recruitment and activity at infection sites.
- Supporting tight junctions that seal epithelial layers against pathogens.
Neutralizing IL-17A weakens these defenses, making skin and upper respiratory/mucosal sites more vulnerable to opportunistic invaders like Candida (causing oral/esophageal candidiasis) or Staphylococcus. Clinical trials showed higher rates of mild fungal skin infections (e.g., tinea) and upper respiratory infections in treated patients compared to placebo.[2][3]
Common Local Infections Reported
- Skin infections: Erythema, pruritus, and fungal issues like candidiasis or tinea infections occur in 1-5% of patients, often at treated sites.
- Mucosal candidiasis: Oral or esophageal thrush in ~3% of psoriasis patients, linked to reduced local IL-17-driven defenses.
- Upper respiratory: Nasopharyngitis or sinusitis, reflecting compromised mucosal immunity.
These are mostly mild and localized, resolving with treatment, but rates rise with dose/duration.[4]
Who Faces Higher Local Risk
Patients with baseline skin barrier issues (e.g., severe psoriasis plaques) or concurrent immunosuppressants see amplified risk. Trials excluded active infections, but real-world data notes flares in diabetics or those with prior candidiasis.[2]
How to Manage Local Risks
Screen for latent infections pre-treatment. Monitor skin/mouth weekly; use topical antifungals for early signs. Discontinue if severe localized spread occurs. No routine prophylaxis needed, per guidelines.[3][5]
[1]: Cosentyx Prescribing Information (Novartis)
[2]: NEJM 2014 Secukinumab Phase 3 Trial
[3]: FDA Label for Secukinumab
[4]: JAMA Dermatology 2017 Post-Marketing Analysis
[5]: AAD Psoriasis Guidelines 2021