INTRODUCTION: This analysis assessed the psychometric properties of the 
Psoriasis Symptoms and Impacts Measure (P-SIM), a novel patient-reported outcome 
(PRO) tool designed to capture patient experiences of the signs, symptoms and 
impacts of psoriasis.
METHODS: Blinded data from the BE RADIANT phase 3b trial of bimekizumab were 
analysed. In BE RADIANT, patients were randomised 1:1 to bimekizumab 320 mg 
every 4 weeks (Q4W) or secukinumab 300 mg (weekly until Week 4, then Q4W). Three 
items (itching, skin pain and scaling) of the P-SIM were electronically assessed 
throughout the trial and were scored from 0 to 10 (none to very severe 
signs/symptoms/impacts). Test-retest reliability was determined using intraclass 
correlations. Convergent validity was assessed between P-SIM and other relevant 
PRO and clinician-reported outcome (ClinRO) scores. Known-groups validity was 
assessed by comparing mean P-SIM item scores between patient subgroups based on 
the Psoriasis Area and Severity Index (PASI)/Investigator's Global Assessment 
(IGA) scores. Responsiveness was assessed via correlations between changes from 
baseline in P-SIM item scores and other relevant PRO and ClinRO scores. 
Anchor-based responder analyses and empirical cumulative distribution function 
(eCDF) curves determined responder thresholds.
RESULTS: The three P-SIM items yielded high intraclass coefficients (> 0.70). By 
Week 48, the three P-SIM items had moderate (> 0.30 and ≤ 0.50) to strong 
(> 0.50) correlations with other PROs and weaker correlations with ClinROs, 
demonstrating good convergent validity. For almost all known-group comparisons, 
statistically significant between-subgroup score differences were seen across 
all three P-SIM items. Changes from baseline in the P-SIM and other relevant 
outcomes were above the acceptable threshold of ≤ 0.30, demonstrating 
sensitivity to change. Anchor-based analyses determined a ≥ four-point reduction 
from baseline to indicate marked clinically meaningful improvement for the 
P-SIM.
CONCLUSION: These results support the validity, reliability and sensitivity to 
change of the P-SIM in assessing key symptoms (itching, skin pain and scaling) 
in patients with moderate to severe plaque psoriasis.
TRIAL REGISTRATION: NCT03536884.