AIMS: To assess safety, pharmacokinetics (PK) and clinical efficacy of 
bimekizumab (formerly UCB4940), a novel humanized monoclonal antibody and dual 
inhibitor of interleukin (IL)-17A and IL-17F, in subjects with mild plaque 
psoriasis.
METHODS: Randomized, double-blind, first-in-human study of bimekizumab in 39 
subjects who received single-dose intravenous bimekizumab (8-640 mg) or placebo 
(NCT02529956).
RESULTS: Bimekizumab demonstrated dose-proportional linear PK and was tolerated 
across the dose range assessed. No subject discontinued due to 
treatment-emergent adverse events and no severe adverse events were reported. 
Bimekizumab demonstrated fast onset of clinically-meaningful effects on skin of 
patients with mild psoriasis as early as Week 2. Maximal improvements (100% or 
near 100% reductions from baseline) in all measures of disease activity were 
observed between Weeks 8-12 in subjects receiving 160-640 mg bimekizumab. The 
duration of effect at doses ≥160 mg was evident up to Weeks 12-20 after a single 
intravenous dose, dependent on endpoint.
CONCLUSIONS: This is the first study to demonstrate the safety, tolerability and 
clinical efficacy of a dual IL-17A and IL-17F inhibitor, in subjects with mild 
psoriasis. Bimekizumab showed fast onset of clinically-meaningful efficacy by 
Week 2, with a maximal or near-maximal magnitude of response that was maintained 
up to study Weeks 12-20. These findings support the continued clinical 
development of bimekizumab for diseases mediated by both IL-17A and IL-17F, 
including psoriasis.