Abstract Background: Studies investigating the molecular basis of psoriasis have 
established the central roles of TNFα, interleukin (IL)-12, IL-22 and IL-23 and 
there is increasing evidence that IL-17 plays a critical role in the complex 
pathophysiology. Preclinical studies suggest that IL-17 is a desirable 
therapeutic target for psoriasis treatment.
METHODS: We reviewed the results of the phase II clinical trials for the 
anti-IL-17 agents secukinumab, ixekizumab and brodalumab in order to assess the 
efficacy and safety profile of each agent.
RESULTS: By week 12, the proportion of patients reaching Psoriasis Area and 
Severity Index (PASI 75) was comparable among the most efficacious dosage 
between the different agents (secukinumab 82%, ixekizumab 83% and brodalumab 
82%; p<0.001 compared to placebo for all agents). The safety profiles of the 
agents were similar with the most frequently reported adverse events of 
nasopharyngitis, upper respiratory infections and injection site reaction. A 
small percentage of patients experienced low-grade neutropenia that was 
predominantly transient and asymptomatic.
CONCLUSION: The anti-IL-17 agents demonstrated a rapid and robust clinical 
improvement accompanied by a favorable short-term safety profile. The results of 
the phase II trials support the theory that the IL-17 pathway is an essential 
target in psoriasis treatment.