Outcomes for Psoriasis by Self-Identified Racial Groups in Ixekizumab Clinical Trials: A Pooled Analysis

February 2024 | Volume 23 | Issue 2 | 17 | Copyright © February 2024


Published online January 26, 2024

doi:10.36849/JDD.7672

Amy McMichael MDa, Valerie Callender MDb, Heather Woolery-Lloyd MDc, Karen Hinkley DVMd, Kyoungah See PhDd, Alyssa Garrelts PhDd, Andrew Alexis MD MPHe

aDepartment of Dermatology, Wake Forest University School of Medicine, Winston-Salem, NC
bCallender Dermatology and Cosmetic Center, Glenn Dale, MD
cDepartment of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL
dEli Lilly and Company, Indianapolis, IN
eDepartment of Dermatology, Weill Cornell Medicine, New York, NY

Abstract
Background: Biologics have shown promising outcomes in psoriasis clinical trials. However, there is a paucity of data exploring the potential differences in outcomes between self-identified racial groups.
Objective: To evaluate treatment response to ixekizumab in patients with psoriasis across different self-identified racial subgroups.
Methods: This study analyzed pooled data from 5 clinical studies (UNCOVER-1, UNCOVER-2, UNCOVER-3, IXORA-R, and IXORA-S) with patients of different self-identified racial subgroups, who were treated with an on-label dose of ixekizumab for psoriasis through 12 weeks. Treatment response to ixekizumab was assessed using the Psoriasis Area and Severity Index (PASI) and static Physician's Global Assessment response rates. Patient Global Assessment of Disease Severity, Itch Numeric Rating Scale, Skin Pain Visual Analog Scale, and Dermatology Life Quality Index were used to evaluate the patient-reported outcomes (PROs) and impact on quality of life (QoL).
Results: A total of 1825 ixekizumab-treated patients from 5 pooled studies were included. Consistent with the clinical outcomes from the overall population, all self-identified racial groups showed rapid improvement in PASI through Week 12, although the response was somewhat slower in American Indian/Alaska Native patients. Differences in PROs and QoL assessments were observed among racial groups, especially in patients who identified as Black/African American and American Indian/Alaska Native.
Conclusion: Ixekizumab is effective through 12 weeks of treatment for psoriasis across different self-identified racial groups. Sample sizes for some racial groups were small (N≤12), therefore, further research is required to understand potential differences in psoriasis treatment with ixekizumab between various racial groups.

J Drugs Dermatol. 2024;23(2):17-22.  doi:10.36849/JDD.7672

INTRODUCTION

Psoriasis is a chronic, immune-mediated skin disease affecting approximately 125 million people worldwide, with a higher reported prevalence in the White population (3.6%) than in people with skin of color (African American: 1.9%; Hispanic: 1.6%; and other race groups: 1.4%).1,2 Recent studies, however, indicate an underestimation of prevalence in non-White patients.3 This may be attributed to healthcare and economic gaps, misdiagnosis, or underrepresentation of psoriasis in patients with skin of color due to different clinical  presentations.3-5 

Despite similarities in psoriasis across different racial groups, differences have been noted in terms of prevalence, clinical presentation, genetics, disease severity, diagnosis, and treatment response.3,6 Current treatment strategies, including biologics, have demonstrated safety and efficacy across diverse racial groups, although these therapies have been tested in clinical trials conducted primarily on White patients.7,8 There are only a limited number of studies that investigate racial differences in treatment response to different therapies.6 Therefore, there is a need to consider data from diverse phenotypes when deciding a treatment strategy in patients with psoriasis. 

The objective of this analysis was to determine the efficacy of ixekizumab, an interleukin (IL)-17A antagonist, across different racial subgroups through 12 weeks of treatment for psoriasis. This is a pooled analysis of 5 pivotal clinical studies in patients with psoriasis (UNCOVER-1, UNCOVER-2, UNCOVER-3, IXORA-R, and IXORA-S),9-11 which assesses skin clearance, patient-reported outcomes (PROs), and quality of life (QoL) for ixekizumab treatment response based on racial subgroups. 
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