Lebrikizumab, an investigational interleukin-13 inhibitor, showed significant efficacy compared with placebo across racial and ethnic subgroups in patients with moderate-to-severe atopic dermatitis.
The finding comes from an analysis of the 16-week induction periods of the phase 3 ADvocate1 and ADvocate2 trials, which Raj Chovatiya, MD, PhD, presented during a late-breaking abstract session at the Revolutionizing Atopic Dermatitis (RAD) Virtual Conference. The efficacy of lebrikizumab monotherapy to treat moderate-to-severe AD has been established in phase 3 studies, "but disease characteristic and efficacy outcomes may vary among racial and ethnic subgroups," said Dr. Chovatiya, assistant professor in the department of dermatology at Northwestern University, Chicago. "The goal of the current study is to report the week 16 efficacy of lebrikizumab-treated patients in racial and ethnic subgroups from ADvocate1 and ADvocate2."
Key eligibility criteria for both trials included adults or adolescents with a diagnosis of AD as defined by the American Academy of Dermatology Consensus Criteria, for at least 1 year prior to screening. They had moderate-to-severe AD, were candidates for systemic therapy, and were dupilumab- and tralokinumab-naive. Outcomes of interest were the Investigator's Global Assessment 0 or 1, with at least a 2-point improvement; and the proportions of patients who achieved Eczema Area and Severity Index (EASI75) and EASI90 responses, and an improvement of 4 points or more on the Pruritus Numeric Rating Scale (NRS).
For statistical analysis, the researchers pooled data from Advocate1 and Advocate2 and applied imputation methodology to the 16-week induction period. Subsequent data from patients who received topical or systemic rescue medication or discontinued treatment due to lack of efficacy were imputed as nonresponders. Subsequent data from patients who discontinued treatment for other reasons were set to missing, and the researchers handled missing data with multiple imputation. They used logistic regression to test the interaction between the treatment and subgroup and the Cochran-Mantel-Haenszel method to evaluate the treatment effect within each subgroup after adjusting for stratification factors.
Dr. Chovatiya reported findings from the 851 study participants in the combined studies. Of these, 542 were White, 192 were Asian, 84 were Black, and 33 were from other racial subgroups. By ethnic subgroup, 748 were not Hispanic or Latino, 91 were Hispanic or Latino, and ethnicity was unknown or not reported for 12 subjects. At baseline, the mean body mass index was slightly higher among Blacks (30.4 kg/m2) and Hispanics (29.4 kg/m2) compared with other racial and ethnic groups, "which reflects general epidemiologic data among these groups in the United States," Dr. Chovatiya said. "You can also see a difference in the balance of IGA scores — they were a little bit more severe in the Black or African American and Hispanic groups as well." The researchers also observed differences in the baseline EASI score across some of these groups, particularly in the Asian individuals, who had higher EASI scores. Prior use of systemic therapy was lower in the Black and "other" subgroups, compared with other racial subgroups.
At week 16, key efficacy endpoints were generally similar between the different racial subgroups. Specifically, 25.1% of Asians in the lebrikizumab treatment group achieved an IGA of 0/1, compared with 4.1% of those in the placebo group (P < .001), while 33.2% of Blacks in the lebrikizumab treatment group achieved an IGA of 0/1, compared with 13.2% of those in the placebo group (no P value was established because this subgroup represented less than 10% of the entire study population). In addition, 43.3% of Whites in the lebrikizumab treatment group achieved an IGA of 0/1, compared with 14.1% of those in the placebo group (P < .001).
In other findings, 45.5% of Asians in the lebrikizumab treatment group achieved an EASI75, compared with 8.5% of those in the placebo group (P < .001), while 51.7% of Blacks in the lebrikizumab treatment group achieved an EASI75, compared with 18.8% of those in the placebo group. Among whites in the lebrikizumab treatment group, 59.7% of achieved an EASI75, compared with 20.4% of those in the placebo group (P < .001).
Dr. Chovatiya said that 26.5% of Asians in the lebrikizumab treatment group achieved an EASI90, compared with 4.3% of those in the placebo group (P < .001), while 26.9% of Blacks in the lebrikizumab treatment group achieved an EASI90, compared with 13.2% of those in the placebo group. In addition, 38.3% of Whites in the lebrikizumab treatment group achieved an EASI90, compared with 10.9% of those in the placebo group (P < .001).
Finally, 36.4% of Asians in the lebrikizumab treatment group achieved a 4-point or greater improvement on the NRS, compared with 5.7% of those in the placebo group (P < .001), while 41.7% of Blacks in the lebrikizumab treatment group achieved a 4-point or greater improvement on the NRS, compared with 17.4% of those in the placebo group. In addition, 45.9% of Whites in the lebrikizumab treatment group achieved a 4-point or greater improvement on the NRS, compared with 14.8% of those in the placebo group (P < .001). Statistical analyses of efficacy endpoints conducted by ethnic group yielded similar results.
Dr. Chovatiya acknowledged certain limitations of the study, including the fact that differences in baseline demographics and disease characteristics limit direct comparison across racial and ethnic subgroups. "Due to the relatively small sample size of some racial and ethnic subgroups and the post hoc nature of this analysis, additional studies are needed to verify these results," he concluded. But for now, he said, the data available indicate that "lebrikizumab is effective across racial and ethnic subgroups for the treatment of moderate-to-severe AD after 16 weeks of monotherapy treatment."
The study was funded by Dermira, a wholly owned subsidiary of Eli Lilly and Company. Dr. Chovatiya disclosed that he is speaker for and/or a consult and advisory board member to many pharmaceutical companies, including Eli Lilly.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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