Efficacy and safety of ixekizumab in Chinese patients with plaque psoriasis

To the Editor: Psoriasis is a common, chronic papulosquamous skin disease occurring worldwide, presenting at any age, and leading to a substantial burden for individuals and society. Interleukin (IL)-17A is considered the key effector cytokine inducing psoriatic inflammation and tissue damage.[1] Ixekizumab is a humanized monoclonal immunoglobulin G specifically binding to and inhibiting IL-17A. The efficacy and safety of ixekizumab in patients with psoriasis have been clearly demonstrated in several randomized clinical trials, namely UNCOVER-1, UNCOVER-2, UNCOVER-3, and UNCOVER-J.[2,3] However, the clinical research data on ixekizumab in Chinese psoriasis patients remain limited. Data were extracted from a retrospective observational study. All participants provided their written informed consent, and they were recruited according to the protocols approved by the institutional ethics committee of Ferry Institute of Dermatology and the First Affiliated Hospital of Anhui Medical University (No. 20210204). Patients were evaluated at four time points: initiation of ixekizumab treatment and 4, 8, and 12 weeks after treatment initiation. At each visit, disease severity was assessed using the psoriasis area and severity index (PASI) scoring system. Efficacy endpoints included PASI 75, PASI 90, and PASI 100, indicating reductions of PASI scores of 75%, 90%, and 100%, respectively; dermatology life quality index (DLQI); investigator's global assessment; and adverse events (AEs). Two certified dermatologists graded the severity and extent of psoriasis using PASI and body surface area (BSA) scores. All patients used only topical agents during the treatment, such as moisturizing agents. Statistical analyses were performed using SPSS 25.0 software (IBM Corp, Armonk, NY, USA). Descriptive statistics were calculated for each variable, using frequencies and percentages for categorical variables and mean and standard deviation for continuous variables. A multiple logistic regression analysis was performed to evaluate the relationship between age, obesity, sex, and clinical efficacy, expressed in terms of absolute PASI value. The demographic and baseline clinical characteristics of the patients are summarized in Supplementary Table 1, https://links.lww.com/CM9/B189. The baseline characteristics were recorded, including gender, age, body mass index (BMI), BSA score, PASI score, DLQI score, previous treatment, and comorbidities. Among 62 patients, 72.5% were males with a mean age of 38.1 ± 15.3 years, and the mean duration of psoriasis was 10.5 ± 10.2 years. A total of 9.7% of patients had received prior biological treatments. The mean baseline BSA and PASI scores were 28.0 ± 18.1 and 15.8 ± 9.5, respectively. The mean DLQI score was 18.7 ± 7.9. The proportion of scalp involvement was 20.9%. The mean PASI score changed from 15.8 at baseline to 0.7 after the 12-week treatment. At week 4, PASI 75, PASI 90, and PASI 100 were reached in 27 (43.5%), 7 (11.3%), and 1 (1.6%) of patients, respectively, with equivalent values of 58 (93.5%), 37 (59.7%), 12 (19.4%) by week 8 and 62 (100.0%), 58 (93.5%), and 38 (61.3%) by week 12, respectively. All patients reached PASI 75 at week 12. PASI scores at 4, 8, and 12 weeks differed significantly compared to baseline levels [Figure 1].Figure 1: PASI score (n = 62). The proportion of PASI 75, PASI 90, and PASI 100 (A) at 4 weeks, 8 weeks, and 12 weeks after treatment initiation (B) differed significantly from baseline levels before treatment. PASI: Psoriasis area and severity index.Additionally, no significant effect of patient characteristics, such as age, gender, age at starting treatment, disease course, BMI, and whether patients had damaged nails, on therapeutic response, was observed in our cohort. During the follow-up, 13 (21.0%) patients experienced one or more AEs. The common treatment-induced AEs were injection site reaction (5, 8.1%), diarrhea (1, 1.6%), common cold (3, 4.8%), urticaria (1, 1.6%), conjunctivitis (2, 3.2%), and back pain (1, 1.6%). One patient discontinued treatment because of urticaria. The AEs detected in our study were generally mild to moderate and resolved spontaneously. There were no serious adverse events throughout the follow-up. This study provided insight into the effectiveness and safety of ixekizumab in a real-world setting in Chinese patients. We reported the results of a retrospective analysis of 62 patients treated with ixekizumab for moderate-to-severe plaque psoriasis over a 12-week period. PASI 75, PASI 90, and PASI 100 were observed in 100.0%, 93.5%, and 61.3% of our patients at week 12, respectively, compared with 93.8%, 82.4%, and 33.0% of patients, respectively, in an ongoing Chinese clinical trial.[4] These differences may be partly explained by differences in the baseline patient characteristics. For example, the mean baseline PASI score and baseline BSA in the previous Chinese clinical data (baseline PASI score: 26.0 ± 10.5 and baseline BSA: 43.0 ± 21.0) were greater than those in our cohort (baseline PASI score: 15.8 ± 9.5 and baseline BSA: 28.0 ± 18.1). Our results also demonstrated that ixekizumab showed similar efficacy in the treatment of plaque psoriasis regardless of the baseline factors, such as age, gender, disease course, and BMI. Even BMI, a feature that seems to influence response to several biological agents,[5] did not modulate the response to ixekizumab in this study. Given that our study only included six patients who were exposed to previous therapies, we did not evaluate the effects of the use of prior drugs on this biologic agent. Finally, severe AEs of IL-17 antagonists reported in some trials, such as inflammatory bowel disease, neutropenia, or severe tuberculosis bacterial, were not observed in this retrospective study. Our study had some limitations, including the small cohort size and short follow-up period. In summary, the results provide valuable information on the use of ixekizumab as in psoriasis. Further clinical studies with larger samples and longer study periods are needed to confirm the efficacy and safety of this drug. Conflicts of interest None.