Introduction: Psoriasis Area and Severity Index (PASI) is a commonly used tool for evaluating skin clearance; patients with ≥90% reduction from baseline PASI (PASI 90) have a level of skin clearance that has been associated with improved quality of life.1 Bimekizumab (BKZ) is a monoclonal IgG1 antibody that selectively inhibits interleukin (IL)-17F in addition to IL-17A.2 High PASI 90 response rates have been observed with BKZ, maintained through three years, across four phase 3/3b trials and an open-label extension (OLE).3–7 Here, we evaluate PASI response through Year 1 in patients who had not had a PASI 90 response during at least one visit up to and including Week 16, in four phase 3/3b trials of BKZ in moderate to severe plaque psoriasis. 
 Methods: Data were pooled from the double-blinded 52-week BE VIVID,3 56-week BE READY,4 56-week BE SURE,5 phase 3 trials, and the 48-week double-blind period of the BE RADIANT6 phase 3b trial. Included patients were randomized to BKZ 320 mg every 4 weeks (Q4W) to Week 16 and then received either BKZ 320 mg Q4W or Q8W maintenance dosing until end of Year 1 (Week 52 for BE VIVID; Week 48 for other trials). Results are reported as observed case (OC).
 Results: Of the 1,362 patients randomized to BKZ across four phase 3/3b trials, 92.6% (n=1,261) had a PASI 90 response during at least one visit up to and including Week 16 while 7.1% (n=97) had not. PASI response was unavailable for 4 patients. The median (minimum, maximum) percent change from baseline PASI among the 97 patients without a PASI 90 response by Week 16 was −77.3 (−89.7, +20.0) at Week 16 (n=78) and −92.9 (−100, +90.7) at Year 1 (n=51).
 Overall, 61.9% (60/97) of patients without a PASI 90 response by Week 16 completed their respective phase 3/3b trials and entered an OLE. By Year 1, 55.0% (33/60) achieved PASI 90 during at least one visit.
 Conclusion: While the vast majority (92.6%) of patients treated with BKZ had a PASI 90 response during at least one visit up to Week 16, a large proportion of patients without a PASI 90 response by Week 16 who completed the phase 3/3b trials and entered an OLE had a PASI 90 response during at least one visit up to Year 1 (55.0%).
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