HLA-C*06:02 Allele and Response to IL-12/23 Inhibition: Results from the Ustekinumab Phase 3 Psoriasis Program.

Several small studies suggest that the presence of the human leukocyte antigen (HLA)-Cw6 (C*06:02) allele may be a predictor of improved response to ustekinumab. This study was designed to assess the association of the HLA-C*06:02 allele with response to ustekinumab in large cohorts of patients from the phase 3 studies of ustekinumab in moderate-to-severe psoriasis. In this retrospective study, both HLA-C*06:02-positive and -negative patients demonstrated good responses to ustekinumab (86% vs. 76%, respectively, achieved at least a 75% improvement from baseline in Psoriasis Area and Severity Index [PASI 75] at week 24). A modestly higher proportion of HLA-C*06:02-positive than HLA-C*06:02-negative patients achieved PASI 75/90 responses at weeks 12 and 24. The largest response difference between the positive and negative patients (17.9%) was observed for PASI 75 (week 12), with smaller differences noted at later time points for PASI 90 (11.8% at week 24) and PASI 100 (10.2% at week 28). A differential response to ustekinumab has been confirmed in HLA-C*06:02-positive versus HLA-C*06:02-negative patients; however, this difference is modest, particularly at the higher response rate thresholds (PASI 90/100) and later time points (weeks 24/28).