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

The Role of Genetics on Psoriasis Susceptibility, Comorbidities, and Treatment Response

This review highlights advances made in psoriasis genetics, including findings from genome-wide association studies, exome-sequencing studies, and copy number variant studies. The impact of genetic variants on various comorbidities and therapeutic responses is discussed.

The association of age at psoriasis onset and HLA-C*06:02 with biologic survival in patients with moderate-to-severe psoriasis: a cohort study from the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR)

BACKGROUND

Few studies have used real-world data to investigate the association between biologic therapy survival and age at psoriasis onset or HLA-C*06:02 status in patients with moderate-to-severe psoriasis. The robustness of these studies is limited by small sample size, short follow-up and diverse safety and effectiveness measures.

OBJECTIVES

To describe biologic survival and explore whether the response to biologics is modified by age at psoriasis onset or HLA-C*06:02 status in patients with moderate-to-severe psoriasis.

METHODS

Data from patients in the UK and the Republic of Ireland registered in the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR) from 2007 to 2022 on a first course of adalimumab, etanercept, secukinumab or ustekinumab with at least 6 months' follow-up and a subset of BADBIR patients with available HLA-C*06:02 information registered to Biomarkers and Stratification To Optimise outcomes in Psoriasis (BSTOP) were analysed. Patients aged ≥ 50 years at treatment initiation were classified into early-onset psoriasis (EOP) (presenting in patients ≤ 40 years of age) and late-onset psoriasis (LOP) (presenting in patients > 40 years of age). BADBIR patients with available information in BSTOP were categorized as HLA-C*06:02- or HLA-C*06:02 + . Biologic survival was defined as treatment discontinuation associated with ineffectiveness or occurrence of adverse events (AEs). Adjusted survival function and hazard ratio (aHR) with 95% confidence interval (CI) were estimated using a flexible parametric model to compare discontinuing therapy between age at psoriasis onset and HLA-C*06:02 groups. Each model included exposure (biologics), effect modifier (age at onset or HLA-C*06:02 status), interaction terms and several baseline demographic, clinical and disease severity covariates.

RESULTS

Final analytical cohorts included 4250 patients in the age at psoriasis onset group [2929 EOP (69%) vs. 1321 LOP (31%)] and 3094 patients in the HLA-C*06:02 status group [1603 HLA-C*06:02+ (52%) vs. 1491 HLA-C*06:02- (48%)]. There was no significant difference between EOP and LOP in drug survival associated with ineffectiveness or AEs for any biologics. However, compared with patients who were HLA-C*06:02-, patients who were HLA-C*06:02 + were less likely to discontinue ustekinumab for reasons associated with ineffectiveness (aHR 0.56, 95% CI 0.42-0.75).

CONCLUSIONS

HLA-C*06:02, but not age at psoriasis onset, is a predictive biomarker for biologic survival in patients with psoriasis. Findings from this large cohort provide further, important information to aid clinicians using biologic therapies to manage patients with psoriasis.

Clinical pharmacokinetics and pharmacodynamics of oral systemic nonbiologic therapies for psoriasis patients

INTRODUCTION

Psoriasis is a chronic inflammatory immune condition. Treatments for psoriasis vary with disease severity, ranging from topicals to systemic biologic agents. The pharmacokinetic (PK) and pharmacodynamic (PD) properties of these therapies establish drug efficacy, toxicity, and optimal dosing to ensure therapeutic drug levels are sustained and adverse effects are minimized.

AREAS COVERED

A literature search was performed on PubMed, Google Scholar, and Ovid MEDLINE for PK and PD, efficacy, and safety data regarding oral systemic nonbiologic therapies utilized for moderate-to-severe plaque psoriasis. The findings were organized into sections for each drug: oral acitretin, methotrexate, cyclosporine, apremilast, tofacitinib, and deucravacitinib.

EXPERT OPINION

Some psoriasis patients may not respond to initial therapy. Ongoing research is evaluating genetic polymorphisms that may predict an improved response to specific medications. However, financial and insurance barriers, as well as limited genetic polymorphisms correlated with treatment response, may restrict the implementation of genetic testing necessary to personalize treatments. How well psoriasis patients adhere to treatment may contribute greatly to variation in response. Therapeutic drug monitoring may help patients adhere to treatment, improve clinical response, and sustain disease control.

Long-Term Drug Survival and Effectiveness of Secukinumab in Patients with Moderate to Severe Chronic Plaque Psoriasis: 42-Month Results from the SUPREME 2.0 Study

Purpose

SUPREME, a phase IIIb study conducted in Italy, demonstrated safety and high efficacy of secukinumab for up to 72 weeks in patients with moderate-to-severe plaque-type psoriasis. SUPREME 2.0 study aimed to provide real-world data on the long-term drug survival and effectiveness of secukinumab beyond 72 weeks.

Patients and Methods

SUPREME 2.0 is a retrospective observational chart review study conducted in patients previously enrolled in SUPREME study. After the end of the SUPREME study, eligible patients continued treatment as per clinical practice, and their effectiveness and drug survival data were retrieved from medical charts.

Results

Of the 415 patients enrolled in the SUPREME study, 297 were included in SUPREME 2.0; of which, 210 (70.7%) continued secukinumab treatment throughout the 42-month observation period. Patients in the biologic-naïve cohort had higher drug survival than those in the biologic-experienced cohort (74.9% vs 61.7%), while HLA-Cw6-positive and HLA-Cw6-negative patients showed similar drug survival (69.3% and 71.9%). After 42 months, Psoriasis Area and Severity Index (PASI) 90 was achieved by 79.6% of patients overall; with a similar proportion of biologic-naïve and biologic-experienced patients achieving PASI90 (79.8% and 79.1%). The mean absolute PASI score reduced from 21.94 to 1.38 in the overall population, 21.90 to 1.24 in biologic-naïve and 22.03 to 1.77 in biologic-experienced patients after 42 months. The decrease in the absolute PASI score was comparable between HLA-Cw6-positive and HLA-Cw6-negative patients. The baseline Dermatology Life Quality Index scores also decreased in the overall patients (10.5 to 2.32) and across all study sub-groups after 42 months. Safety was consistent with the known profile of secukinumab, with no new findings.

Conclusion

In this real-world cohort study, secukinumab showed consistently high long-term drug survival and effectiveness with a favourable safety profile.

Genetic Influence on Treatment Response in Psoriasis: New Insights into Personalized Medicine

Psoriasis is a chronic inflammatory disease with an established genetic background. The HLA-Cw*06 allele and different polymorphisms in genes involved in inflammatory responses and keratinocyte proliferation have been associated with the development of the disease. Despite the effectiveness and safety of psoriasis treatment, a significant percentage of patients still do not achieve adequate disease control. Pharmacogenetic and pharmacogenomic studies on how genetic variations affect drug efficacy and toxicity could provide important clues in this respect. This comprehensive review assessed the available evidence for the role that those different genetic variations may play in the response to psoriasis treatment. One hundred fourteen articles were included in this qualitative synthesis. VDR gene polymorphisms may influence the response to topical vitamin D analogs and phototherapy. Variations affecting the ABC transporter seem to play a role in methotrexate and cyclosporine outcomes. Several single-nucleotide polymorphisms affecting different genes are involved with anti-TNF-α response modulation (TNF-α, TNFRSF1A, TNFRSF1B, TNFAIP3, FCGR2A, FCGR3A, IL-17F, IL-17R, and IL-23R, among others) with conflicting results. HLA-Cw*06 has been the most extensively studied allele, although it has only been robustly related to the response to ustekinumab. However, further research is needed to firmly establish the usefulness of these genetic biomarkers in clinical practice.

Pharmacogenomics on the Treatment Response in Patients with Psoriasis: An Updated Review

The efficacy and the safety of psoriasis medications have been proved in trials, but unideal responses and side effects are noted in clinical practice. Genetic predisposition is known to contribute to the pathogenesis of psoriasis. Hence, pharmacogenomics gives the hint of predictive treatment response individually. This review highlights the current pharmacogenetic and pharmacogenomic studies of medical therapy in psoriasis. HLA-Cw*06 status remains the most promising predictive treatment response in certain drugs. Numerous genetic variants (such as ABC transporter, DNMT3b, MTHFR, ANKLE1, IL-12B, IL-23R, MALT1, CDKAL1, IL17RA, IL1B, LY96, TLR2, etc.) are also found to be associated with treatment response for methotrexate, cyclosporin, acitretin, anti-TNF, anti-IL-12/23, anti-IL-17, anti-PDE4 agents, and topical therapy. Due to the high throughput sequencing technologies and the dramatic increase in sequencing cost, pharmacogenomic tests prior to treatment by whole exome sequencing or whole genome sequencing may be applied in clinical in the future. Further investigations are necessary to manifest potential genetic markers for psoriasis treatments.

Real-world use of ustekinumab therapeutic drug monitoring in moderate to severe psoriasis

Introduction

There is growing evidence that therapeutic drug monitoring of biologic therapy is beneficial in psoriatic patients. With respect to ustekinumab, the available evidence has not shown any relationship yet. The objective of this study is to identify correlations among ustekinumab trough concentrations, anti-ustekinumab antibodies and clinical response in moderate-to-severe plaque psoriasis patients, in a real-world setting.

Methods

Observational prospective follow-up study in psoriatic patients treated with ustekinumab. Patients were classified in optimal (PASI ≤ 3) and suboptimal responders (PASI > 3). Mann-Whitney U test and Spearman's rank correlation coefficient were used. Receiver-operator characteristic curve analysis was performed to identify ustekinumab concentration cut-off to achieve optimal response. A p-value < 0.05 was considered statistically significant.

Results

A total of 59 patients were included. Forty-eight patients (81.4%) corresponded to optimal responders and 11 (18.6%) to suboptimal responders. There was significant difference to ustekinumab concentrations: 0.7 μg/mL (range <0.1-1.8) vs. 0.4 μg/mL (range <0.1-0.8) respectively (p = 0.007). Positive correlation between ustekinumab concentration and psoriasis area and severity index (PASI) value was detected (p = 0.009). A cut-off value of 0.6 μg/mL ustekinumab concentration was found to achieve clinical response. Anti-ustekinumab antibodies were detected in 2 (3.4%) samples, both suboptimal responders.

Conclusion

A positive correlation exits between ustekinumab concentration and clinical response (optimal response PASI values ≤ 3) in blood draws performed before drug administration. The measurement of anti-ustekinumab antibodies could be considered in treatment failure.

Genome-Wide Association Study of Ustekinumab Response in Psoriasis

Heterogeneous genetic and environmental factors contribute to the psoriasis phenotype, resulting in a wide range of patient response to targeted therapies. Here, we investigate genetic factors associated with response to the IL-12/23 inhibitor ustekinumab in psoriasis. To date, only HLA-C*06:02 has been consistently reported to associate with ustekinumab response in psoriasis. Genome-wide association testing was performed on the continuous outcome of percent change in Psoriasis Area Severity Index (PASI) at 12 weeks of ustekinumab therapy relative to baseline. A total of 439 European ancestry individuals with psoriasis were included [mean age, 46.6 years; 277 men (63.1%)]. 310 (70.6%) of the participants comprised the discovery cohort and the remaining 129 (29.4%) individuals comprised the validation cohort. Chromosome 4 variant rs35569429 was significantly associated with ustekinumab response at 12 weeks at a genome-wide significant level in the discovery cohort and replicated in the validation cohort. Of psoriasis subjects with at least one copy of the deletion allele of rs35569429, 44% achieved PASI75 (75% improvement in PASI from baseline) at week 12 of ustekinumab treatment, while for subjects without the deletion allele, 75% achieved PASI75 at week 12. We found that differences in treatment response increased when rs35569429 was considered alongside HLA-C*06:02. Psoriasis patients with the deletion allele of rs35569429 who were HLA-C*06:02 negative had a PASI75 response rate of 35% at week 12, while those without the deletion allele who were HLA-C*06:02 positive had a PASI75 response rate of 82% at week 12. Through GWAS, we identified a novel SNP that is potentially associated with response to ustekinumab in psoriasis.

TaaI/Cdx-2 AA Variant of VDR Defines the Response to Phototherapy amongst Patients with Psoriasis

1,25-dihydroxyvitamin-D₃ plays a central role in the immune system via binding to the vitamin D receptor. VDR polymorphisms have been associated with multiple autoimmune disorders, including psoriasis. Until now, five VDR polymorphisms, FokI, ApaI, BsmI, TaqI and TaaI/Cdx2, have been studied in psoriasis, with contradicting results. Therefore, this study aimed to evaluate the association of VDR polymorphisms with susceptibility to psoriasis, effectiveness of NB-UVB phototherapy and concentration of proinflammatory cytokines and vitamin D amongst the Polish population. VDR polymorphisms were analyzed by PCR-RFLP or real-time PCR. We found that the frequency of the TaaI/Cdx-2 GG genotype was significantly higher in psoriasis patients and was associated with regulation of IL-17 and IL-23 concentration. Moreover, TaaI/Cdx-2 AA might have a significant effect on the response to phototherapy amongst patients with psoriasis. Our results suggest that VDR is a susceptibility factor for psoriasis development. Moreover, TaaI/Cdx-2 variants have a significant effect on the response to phototherapy amongst patients with psoriasis and regulation of inflammatory response via decrease of IL-17 and IL-23 level after UVB phototherapy in the Polish population. Results of our study provide some evidence in support of the hypothesis that the vitamin D signaling pathway may be of relevance for pathogenesis and treatment of psoriasis.

Influence of Genetic Polymorphisms on Response to Biologics in Moderate-to-Severe Psoriasis

Psoriasis is a chronic inflammatory skin pathology of autoimmune origin and unknown etiology. There are various therapies for treating it, including a wide range of biopharmaceuticals indicated in moderate-to-severe psoriasis. Depending on their therapeutic target, they are classified as tumor necrosis factor inhibitors (anti-TNF) or cytokine inhibitors (interleukin-12, 23, and 17 antagonists). Although they have proved effective and safe, in clinical practice, many patients show a short- and long-term suboptimal response and even varying degrees of toxicity. This variability in response may be influenced by genetic factors, such as polymorphisms in the genes involved in the pathological environment, metabolism or mechanism of action of the drug that could affect the effectiveness and toxicity of biological therapies. This review assesses pharmacogenetic studies of the impact of genetic factors on response to biopharmaceuticals and toxicity in patients diagnosed with moderate-to-severe psoriasis. The results suggest that polymorphisms detected in the HLA genes, in genes that encode cytokines (TNF, IL genes, TNFAIP3), transporters (PDE3A-SLCO1C1, SLC12A8), receptors (TNFRSF1B, CD84, FCGR2A and FCGR3A, IL17RA, IL23R, TLR genes, PGLYRP4) and associated proteins (TNFAIP3, LY96, TIRAP, FBXL19), as well as other genes implicated in the pathogenesis of psoriasis (CDKAL1, CARD14, PTTG1, MAP3K1, ZNF816A, GBP6, CTNNA2, HTR2A, CTLA4, TAP1) can be used in the future as predictive markers of treatment response and/or toxicity with biological therapies in patients diagnosed with moderate-to-severe psoriasis, tailoring treatment to the individual patient.

Clinical outcomes in adult patients with plaque psoriasis treated with ustekinumab under real-world practice in Korea: A prospective, observational, multi-center, postmarketing surveillance study

Postmarketing surveillance is conducted to establish drug safety and effectiveness under real-world practice. We aimed to validate the effectiveness and safety of ustekinumab in the treatment of adult Korean patients with plaque psoriasis under real-world practice. This was a prospective, observational, and multi-center study. Subjects aged 18 years or older who were treated with ustekinumab for plaque psoriasis were enrolled. We enrolled 977 patients; 654 (66.9%) were men, with mean body surface area (BSA, ± standard deviation) of 27.0 ± 18.3% and mean psoriasis area severity index (PASI) score of 18.1 ± 9.7. The effectiveness analysis was performed in 581 patients who had at least one follow-up assessment and met treatment criteria per local label and reimbursement guidelines. Of these patients, 287 had effectiveness data for visit 6 at 53.7 ± 2.1 weeks. At visit 6, 91.6% (263/287), 51.2% (147/287), and 9.4% (27/287) patients achieved PASI 75, 90, and 100 responses, respectively. Adverse events (AEs) occurred in 112 of the 977 (11.5%) patients with an incidence rate of 21.5 per 100 patient-years (PYs). Serious AEs occurred in eight (0.8%) patients with an incidence rate of 1.2 per 100 PYs. The estimated 1-year drug survival rate was 87.7%. The multiple logistic regression analysis showed that higher baseline PASI score and no prior biologic exposure were significant predictors for PASI 90 response at visit 6. Ustekinumab was effective and safe, and displayed a high survival rate in the treatment of adult Korean patients with plaque psoriasis in real-world practice.

HLA-Cw6 status and treatment responses between psoriasis patients

Background

The number of treatment options in psoriasis has increased considerably, so biomarkers should be searched to assist in the selection of the optimal treatment agent. The most common of these biomarkers is HLA-Cw6.

Objective:

The aim was to determine whether there is a relationship between HLA-Cw6-positivity (HLA-Cw6-POS) and the response of treatment agents in psoriasis.

Methods:

Blood samples of 124 patients were subjected to genetic study for HLA-Cw6.

Results:

Psoriasis area severity index (PASI) score of more than 75% (PASI75) response was received in 34 (73.9%) of the HLA-Cw6-POS methotrexate-treated patients, 30 (78.9%) of the HLA-Cw6-POS cyclosporine-treated patients, and 8 (37.5%) of the HLA-Cw6-POS acitretin-treated patients. The differences were not statistically significant (P = 0.634-0.071-0.409). PASI75 response was received in 73 (68.2%) of the HLA-Cw6-POS patients in patients treated with conventional agents. In adalimumab-treated patients, PASI75 response was received in 8 (53.3%) of the HLA-Cw6-POS patients, 6 (75%) of the HLA-Cw6-POS infliximab-treated patients, and 4 (57.1%) of the HLA-Cw6-POS ustekinumab-treated patients. The differences were not statistically significant (P = 0.245-1.00-0.322). PASI75 response was received in 24 (64.9%) of the HLA-Cw6-POS and 33 (84.6%) of HLA-Cw6 negative (HLA-Cw6-NEG) patients with biological agents. The biological agent response was statistically significantly lower in HLA-Cw6-POS.

Conclusion:

None of the agents were affected by HLA-Cw6. When biological agents were evaluated collectively, the treatment response of HLA-Cw6-POS patients was lower.

Pharmacogenetics Update on Biologic Therapy in Psoriasis

Background and objectives: Psoriasis is a chronic immune-mediated skin disease caused by several complex factors, both environmental and genetic, many of which are still not fully understood. Nowadays, several groups of biological drugs are being used for psoriasis treatment. Although these therapies are very effective, they show significant variability in efficacy among individuals. Therefore, there is a need for biomarkers to predict treatment outcomes in order to guide personalized therapeutic decisions. Pharmacogenetics is the study of variations in DNA sequences related to drug response. Materials and Methods: In this article, we review pharmacogenetics studies on the treatment of moderate-to-severe psoriasis focusing on anti-interleukin (IL) 12/23 (ustekinumab) and anti-IL17 drugs (secukinumab and ixekizumab), as well as recent studies concerning anti-TNF drugs. Results: Several polymorphisms have been studied over the years in reference to anti-TNF drugs; some of the most recent studies included the performance of a genome-wide association study (GWAS) and pharmacogenetics studies focused on the optimization of a treatment regimen. Various polymorphisms in different genes have been related to ustekinumab response; among them, the most commonly studied is the HLA-C*06:02 allele. Conclusions: Although not confirmed in some studies, most studies have shown that patients carrying this allele present a significantly higher response rate to ustekinumab. Some polymorphisms have been studied in patients treated with anti-IL17 drugs, mostly related to secukinumab; however, up to now, no association has been found between any of these polymorphisms and response. Nevertheless, further studies involving larger cohorts are needed in order to confirm these results before the implementation of this biomarker in clinical practice.

Progress to Date in Advancing Stratified Medicine in Psoriasis

Stratified medicine is the tailoring of treatment to the individual characteristics of each patient. This is a challenging task in the context of psoriasis, a complex disease with a variety of phenotypic presentations and a comorbidity burden that extends beyond cutaneous manifestations. In recent years, considerable progress has been made in understanding the immunology of psoriasis, and this has informed the development of increasingly precise and efficacious therapies. However, not all patients respond to biologic therapy, and access is limited to patients with moderate to severe disease. However, subpopulations of patients are emerging with distinct patterns of response to therapy, largely determined by clinical and pharmacogenomic factors. Despite progress to date, the natural history of psoriasis remains poorly understood. It is likely that disease onset, progression, development of comorbidities and response to therapy are due to a combination of genetic, inflammatory and environmental factors. We envision that a greater understanding of the natural history of psoriasis will be a key factor in progressing a stratified medicine approach to patient care, as will earlier intervention in the course of the disease.

The HLA-Cw6 Dilemma: Is It Really an Outcome Predictor in Psoriasis Patients under Biologic Therapy? A Monocentric Retrospective Analysis

HLA-Cw6 is one of the most strongly associated psoriasis susceptibility alleles. Data regarding correlation between HLA-Cw6 status and biologic treatment outcomes are divergent. The aim of our study in our cohort of psoriatic patients was to explore if the HLA-Cw6 status influences the response rate to biologic therapies at 16 and 48 weeks. One hundred and one psoriatic patients eligible for biologic therapies were enrolled. HLA-C*06 alleles were detected from their blood samples. The effectiveness of antipsoriatic treatments was reported as 90% Psoriasis Area and Severity Index reduction (PASI90). All biologics showed efficacy at week 16, without significant differences between one another. HLA-Cw6 status did not seem to affect baseline characteristics, or treatment response at week 16. At week 48, IL-12/23 and IL-17 targeting drugs were more effective on Cw6-positive patients than on Cw6-negative patients. Conversely, TNF-targeting drugs seemed to be more effective on Cw6- negative patients than on Cw6-positive patients. The HLA-Cw6 test could well deserve to be integrated into the clinical laboratory work-up supporting the choice of the correct biologic.

Small molecules under development for psoriasis: on the road to the individualized therapies

Psoriasis is an incurable cutaneous illness characterized by the presence of well-delimited reddish plaques and silvery-white dry scales. So far, there is a limited understanding of its pathogenesis, though recent discoveries on the immunological, genetic and molecular aspects of this disease have significantly contributed to the identification of new targets and the development of novel drugs. Despite these advances, many patients are still dissatisfied, so to improve patient satisfaction, reliability, and clinical outcomes, the individualization of the treatments for this disease becomes a necessity. This review summarizes recent findings related to psoriasis pathogenesis and describes new small molecules and targets recently identified as promising for treatments. Additionally, the current status, challenges and the future directions for achieving individualized therapy for this disease and the need for more collaborative studies are discussed. The individualization of treatments for psoriasis, rather than a goal, is analyzed as a process where a dynamic integration between the needs and characteristics of the patients, the pharmacological progress, and the clinical decisions takes place.

Role of the IL-23 pathway in the pathogenesis and treatment of enthesitis in psoriatic arthritis

INTRODUCTION

Enthesitis is a key feature of spondyloarthritis (SpA). Several studies have underlined the role of interleukin (IL)-23 in SpA development as a crucial cytokine in the pathogenesis of enthesitis.

AREA COVERED

This review summarizes recent evidence of the role of IL-23 in the pathogenesis of and as a target of the treatment of enthesitis. We review the definition, diagnosis and clinical impact of enthesitis and its connection with microbial infections, gut dysbiosis, and mechanical stress. We also review clinical trials and real-life studies of drugs targeting the p19 or p40 subunits of IL-23.

EXPERT OPINION

Novel therapies targeting the p19 or p40 subunit of IL-23 appear to be promising treatment options for patients with enthesitis. Although we are currently unable to identify the best therapeutic window to target IL-23 in SpA disease evolution, the promising ability of this therapy to control the gut-entheseal axis is increasing our knowledge of SpA pathogenesis.

Association of HLA-C*06:02 Status With Differential Response to Ustekinumab in Patients With Psoriasis: A Systematic Review and Meta-analysis

Importance

Previous research showed a differential response to ustekinumab therapy based on HLA-C*06:02 status in patients with psoriasis but consisted mostly of small (and sometimes inconclusive) cohort studies.

Objective

To assess whether HLA-C*06:02 status is associated with a differential response to ustekinumab therapy in patients with psoriasis through a systematic review and a meta-analysis of available data.

Data Sources

A comprehensive search was conducted using MEDLINE, Embase, the Cochrane Library, Web of Science, and gray literature sources. Databases were searched from January 1, 2000, to May 14, 2018. Search strategies included terms and synonyms for psoriasis, HLA-C, and ustekinumab. Languages were restricted to English, French, German, and Dutch.

Study Selection

Studies were included if they reported the association between HLA-C*06:02 status and 75% improvement in Psoriasis Area and Severity Index (PASI75) response to ustekinumab therapy in patients with plaque psoriasis after 6 and/or 3 months of treatment. Randomized clinical trials and observational studies were included. Screening and selection were performed independently by 2 reviewers.

Data Extraction and Synthesis

HLA-C*06:02 genotype status and PASI75 response rates were extracted by 2 reviewers. Data were pooled using random-effects models. Heterogeneity was assessed using the τ2 and I2 statistic. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) and Meta-Analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines were followed.

Main Outcome and Measure

The primary outcome was the risk difference of achieving PASI75 after 6 months of ustekinumab therapy between HLA-C*06:02-positive and HLA-C*06:02-negative patients.

Results

A total of 8 studies were reviewed; 1048 patients were included for meta-analyses, and 937 patients were included for the primary analysis of PASI75 response after 6 months of treatment. Random-effects meta-analysis showed a risk difference of 0.24 (95% CI, 0.14-0.35; P < .001) in favor of HLA-C*06:02-positive patients. The median PASI75 response rate in the HLA-C*06:02-positive group was 92% (pooled, 89%; range, 62%-98%). For HLA-C*06:02-negative patients, the median response rate was 67% (pooled, 62%; range, 40%-84%). Substantial heterogeneity may have been present, with an I2 of 82%.

Conclusions and Relevance

The meta-analysis showed a differential response to ustekinumab therapy based on HLA-C*06:02 status in patients with psoriasis. Although HLA-C*06:02-positive patients had high PASI75 response rates after 6 months, the PASI75 response rate was also high in the HLA-C*06:02-negative group. There appears to be no rationale for excluding patients from ustekinumab treatment based on a negative HLA-C*06:02 status.

Response to IL-17A inhibitors secukinumab and ixekizumab cannot be explained by genetic variation in the protein-coding and untranslated regions of the IL-17A gene: results from a multicentre study of four European psoriasis cohorts

BACKGROUND

Genetic predictors for treatment response could optimize allocation of biological treatment in patients with psoriasis. There is minimal knowledge about pharmacogenetics of anti-IL-17 agents.

OBJECTIVES

To assess whether genetic variants in the protein-coding region or untranslated regions of the IL-17A gene are associated with response to IL-17A inhibitors in patients with psoriasis.

METHODS

This was a multicenter European cohort study investigating pharmacogenetics of IL-17A inhibitors in patients with psoriasis. Patients with plaque psoriasis treated with secukinumab or ixekizumab in daily practice were included. For all participants, the protein-coding region and untranslated regions of the IL-17A gene were analysed using Sanger sequencing. Identified genetic variants were tested for association with response to secukinumab/ixekizumab, measured as ∆PASI, after 12 weeks (primary outcome) and after 24 weeks (secondary outcome). Association was tested using a linear regression model with correction for baseline PASI as a fixed covariate and for biological naivety and body mass index as additional covariates.

RESULTS

In total, 134 patients treated with secukinumab or ixekizumab were included. Genotyping of the cohort identified genetic variants present in untranslated regions and intronic DNA, but not in the protein-coding region of the IL-17A gene. Five genetic variants in non-coding DNA with a known or suspected functional effect on IL-17A expression were selected for association analyses: rs2275913, rs8193037, rs3819025, rs7747909 and rs3748067. After 12 weeks, 62% of patients achieved PASI75 and 39% achieved PASI90. At week 24, PASI75 and PASI90 response rates were 72% and 62%, respectively. No associations were found between the five genetic variants and ∆PASI, PASI75 or PASI90 after 12 and 24 weeks of anti-IL-17A treatment.

CONCLUSIONS

Response to IL-17A inhibitors secukinumab and ixekizumab cannot be explained by genetic variation in the protein-coding and untranslated regions of the IL-17A gene. Pharmacogenetics of IL-17A inhibitors in the treatment of psoriasis requires further exploration.

HLA-C: An Accomplice in Rheumatic Diseases

Human leukocyte antigen c (HLA-C) is a polymorphic membrane protein encoded by the HLA-C gene in the class I major histocompatibility complex. HLA-C plays an essential role in protection against cancer and viruses but has also been implicated in allograft rejection, preeclampsia, and autoimmune disease. This review summarizes reports and proposed mechanisms for the accessory role of HLA-C in rheumatic diseases. Historically, contributions of HLA-C to rheumatic diseases were eclipsed by the stronger association with HLA-DRB1 alleles containing the "shared epitope" with rheumatoid arthritis. Larger genetic association studies and more powerful analytical approaches have revealed independent associations of HLA-C with rheumatic disease-associated phenotypes, including development of anticitrullinated peptide antibodies. HLA-C functions by presenting antigens to T cells and by binding activatory and inhibitory receptors on natural killer (NK) cells, but the exact mechanisms by which the HLA-C locus contributes to autoimmunity are largely undefined. Studies have suggested that HLA-C and NK cell receptor polymorphisms may predict responsiveness to pharmacotherapy. Understanding the mechanisms of the role of HLA-C in rheumatic disease could uncover therapeutic targets or guide precision pharmacologic treatments.

Review article: the genetics of the human leucocyte antigen region in inflammatory bowel disease

BACKGROUND

The human leucocyte antigen (HLA) complex, located at chromosome 6p21.3 is a highly polymorphic region containing the classical class I and II HLA genes. The region is highly associated with inflammatory bowel disease (IBD), largely through genome-wide association studies (GWAS).

AIMS

To review the role of HLA in immune function, summarise data on risk/protective HLA genotypes for IBD, discuss the role of HLA in IBD pathogenesis, treatment and examine limitations that might be addressed by future research.

METHODS

An organised search strategy was used to collate articles describing HLA genes in IBD, including Crohn's disease and ulcerative colitis.

RESULTS

All classical HLA genes with variation (including HLA-A, B, C, DRB1, DQA1, DQB1, DPA1 and DPB1) harbour IBD-associated genotypes. The most implicated gene is HLA-DRB1, with HLA-DRB1*03:01 the most associated risk allele in both Crohn's disease and ulcerative colitis. Elucidating precise disease associations is challenging due to high linkage disequilibrium between HLA genotypes. The mechanisms by which risk alleles cause disease are multifactorial, with the best evidence indicating structural and electrostatic alteration impacting antigen binding and downstream signalling. Adverse medication events have been associated with HLA genotypes including with thiopurines (pancreatitis) and anti-TNF agents (antibody formation).

CONCLUSIONS

The HLA complex is associated with multiple risk/protective alleles for IBD. Future research utilising long-read technology, ascertainment of zygosity and integration in disease modelling will improve the functional understanding and clinical translation of genetic findings.

Effect of Age of Onset of Psoriasis on Clinical Outcomes with Systemic Treatment in the Psoriasis Longitudinal Assessment and Registry (PSOLAR)

OBJECTIVE

Our objective was to compare therapeutic response among patients with early-onset psoriasis (EOP) and late-onset psoriasis (LOP) receiving adalimumab, etanercept, infliximab, ustekinumab, or methotrexate in the Psoriasis Longitudinal Assessment and Registry (PSOLAR).

METHODS

Patients were grouped by age of onset: EOP (age ≤ 40 years) or LOP (age > 40 years). Repeated-measures analysis with logistic regression was used to calculate the adjusted odds ratio (AOR; adjusted for baseline characteristics) for achieving a Physician's Global Assessment score of cleared/minimal (PGA 0/1) or a percentage of body surface area involved with psoriasis < 3% (%BSA < 3) or %BSA < 1 for all patients; similar sensitivity analyses were performed for each treatment group.

RESULTS

Of 7511 patients, 5479 (72.9%) had EOP. The LOP group had a higher likelihood of achieving PGA 0/1 after treatment than did the EOP group in all patients (AOR 1.14 [95% confidence interval (CI) 1.05-1.25]; p = 0.0019); the same was true in subgroups of etanercept-treated (AOR 1.38 [95% CI 1.14-1.66]; p = 0.0010) and methotrexate-treated (AOR 1.62 [95% CI 1.16-2.26]; p = 0.0049) patients. No significant difference was found between the EOP and LOP groups with regard to the likelihood of achieving %BSA < 3 or %BSA < 1 among all patients. However, LOP patients were more likely than EOP patients to achieve %BSA < 3 or %BSA < 1 in subgroups treated with infliximab (AOR 1.45 [95% CI 1.09-1.93; p = 0.0103] and AOR 1.36 [95% CI 1.03-1.78; p = 0.0290], respectively) and etanercept (AOR 1.30 [95% CI 1.06-1.61; p = 0.0123] and AOR 1.34 [95% CI 1.09-1.64; p = 0.0053], respectively).

CONCLUSION

Our real-world data from PSOLAR indicate that there are differences in some patient characteristics between EOP and LOP and that patients with EOP are less likely than those with LOP to respond to certain systemic treatments. (ClinicalTrials.gov identifier: NCT00508547).

Pharmacogenetics and Pharmacogenomics in Moderate-to-Severe Psoriasis

Pharmacogenetics is the study of variations in DNA sequence related to drug response. Moreover, the evolution of biotechnology and the sequencing of human DNA have allowed the creation of pharmacogenomics, a branch of genetics that analyzes human genes, the RNAs and proteins encoded by them, and the inter-and intra-individual variations in expression and function in relation to drug response. Pharmacogenetics and pharmacogenomics are being used to search for biomarkers that can predict response to systemic treatments, including those for moderate-to-severe psoriasis. Psoriasis is a chronic inflammatory disease with an autoimmune contribution. Although its etiology remains unknown, genetic, epigenetic, and environmental factors play a role in its development. Diverse systemic and biologic therapies are used to treat moderate-to-severe psoriasis. However, these treatments are not curative, and patients exhibit a wide range of responses to them. Moderate-to-severe psoriasis is usually treated with systemic immunomodulators such as acitretin, ciclosporin, and methotrexate. Anti-tumor necrosis factor (TNF) drugs (adalimumab, etanercept, or infliximab) are the first-line treatment for patients resistant to conventional systemic therapies. Although these therapies are very efficient, around 30-50% of patients have inadequate response. Ustekinumab is a monoclonal antibody that targets interleukin (IL)-12 and IL-23 and is used for moderate-to-severe psoriasis. New drugs (apremilast, brodalumab, guselkumab, ixekizumab, and secukinumab) have recently been approved for psoriasis. However, response rates to systemic treatments for moderate-to-severe psoriasis range from 35 to 80%, so it is necessary to identify non-invasive biomarkers that could help predict treatment outcomes of these therapies and individualize care for patients with psoriasis. These biomarkers could improve patient quality of life and reduce health costs and potential side effects. Pharmacogenetic studies have identified potential biomarkers for response to biologic treatments for moderate-to-severe psoriasis. These biomarkers need to be validated in clinical trials involving large cohorts of patients before they can be translated to the clinic. We review pharmacogenetics and pharmacogenomics studies for the treatment of moderate-to-severe plaque psoriasis.

Limited clinical utility of HLA-Cw6 genotyping for outcome prediction in psoriasis patients under ustekinumab therapy: a monocentric, retrospective analysis

Purpose

Several studies have suggested that an HLA-Cw6+ allele can predict an improved outcome of treatment in psoriasis patients. The aim of the study was to assess whether the published association between HLA-Cw6 allele carriers and response to ustekinumab has the potential to impact treatment decisions.

Patients and methods

Differences in Psoriasis Activity and Severity Index 50, 75, and 90; Nail Psoriasis Severity Index; and Dermatology Life Quality Index at 16 weeks were evaluated between HLA-Cw6 allele carriers vs. non-carriers. Thirty patients with moderate-to-severe psoriasis under treatment with ustekinumab were included in our study.

Results

There was no difference between the two groups with respect to Psoriasis Activity and Severity Index 50, 75, and 90 or in terms of change in Nail Psoriasis Severity Index or Dermatology Life Quality Index.

Conclusion

In our retrospectively analyzed cohort, we could not detect the previously reported better response in HLA-Cw6+ vs. HLA-Cw6- patients.

HLA-Cw6 and psoriasis

Psoriasis is a multifactorial disease with a strong genetic background. HLA-Cw6 is one of the most strongly associated psoriasis susceptibility alleles. It is repeatedly observed to affect disease course, phenotypic features, severity, comorbidities and treatment outcomes. To the best of our knowledge, the roles of HLA-Cw6 in psoriasis have not yet been thoroughly reviewed. The worldwide frequency of the HLA-Cw6 allele varies greatly, with it being generally higher in white people than in Asians. The allele is associated with type I early-onset psoriasis. Stress, obesity and streptococcal pharyngitis are commonly observed in HLA-Cw6-positive patients. Phenotypically, HLA-Cw6 has been found to be associated with guttate psoriasis. In addition, patients carrying the allele are more likely to have arm, leg and trunk involvement, and the Koebner phenomenon. Patients with psoriatic arthritis with HLA-Cw6 more often have early onset and tend to show cutaneous symptoms before musculoskeletal symptoms. HLA-Cw6-positive patients have been shown in several studies to be more responsive to methotrexate and ustekinumab. However, this difference in ustekinumab efficacy was only moderate in a post-hoc analysis of a pivotal phase III study. HLA-Cw6 positivity also tends to be less frequent in high-need patients who fail conventional therapy. Small studies have also investigated the role of HLA-Cw6 in remission of psoriasis during pregnancy, and with the comorbidities of photosensitivity and atherosclerosis. Given the diverse nature of psoriasis pathogenesis, as well as the difference of HLA-Cw6 positivity in different ethnic groups, more studies are needed to confirm the role of HLA-Cw6 in psoriasis.

A systematic review of pharmacogenetic studies on the response to biologics in patients with psoriasis

BACKGROUND

Biologics are indicated for treating moderate-to-severe psoriasis. As the number of biologics registered for the treatment of psoriasis increases, so does the need for biomarkers to guide personalized therapeutic decisions. Genetic variants might serve as predictors for treatment response, a field of research known as pharmacogenetics.

OBJECTIVES

To assess which genetic variants are associated with response to biologics in patients with psoriasis according to current literature.

METHODS

A systematic search was performed in Embase, MEDLINE, the Cochrane Library and Web of Science. In total, 26 papers were included in this systematic review; 24 original studies and two meta-analyses. Quality was assessed using a predesigned form and risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

The majority of studies reported a candidate gene approach, focusing on polymorphisms in genes related to the therapeutic target or to psoriasis susceptibility. Studied populations were small and results were divergent, especially for studies investigating tumour necrosis factor inhibitors. The evidence for the role of HLA-Cw6 in ustekinumab efficacy shows minimal heterogeneity, with a higher response rate among patients who were positive for HLA-Cw6 reported across three of five studies.

CONCLUSIONS

Pharmacogenetic studies in psoriasis have generated divergent results. Replication of findings in larger cohorts is required. Large-scale hypothesis-free searches for genetic biomarkers are needed to uncover the complete genetic background of outcomes for treatment with biologics.

Psoriasis Therapy: Breakthroughs in Pharmacogenomics or in Pharmacology?

As the cost of psoriasis therapies skyrockets, it becomes increasingly important to find biomarkers that predict which patients will respond to expensive medications. The ability to predict response to a specific therapy is particularly important for medications that are effective in only a small portion of the population. As we develop medications that clear most patients, the need for a predictive biomarker diminishes. Nevertheless, the importance of pharmacogenomics is likely to increase as the cost of drugs continues to rise.

Recent Highlights in Psoriasis Research

This article highlights recent advances in the immunology, epidemiology, and genetics/genomics of psoriasis. Advances sometimes generate more questions, and this article makes an attempt to point out where controversies might exist in the literature. Many of the articles mentioned were published in the Journal of Investigative Dermatology, but many articles from the broader scientific literature are also cited, to provide context and to add further validity for some of these key findings. Among the themes we explore are the identification of antigens in psoriasis, the co-morbidities of psoriasis, and novel integrative approaches to genome-wide association studies.

Pharmacogenetics of ustekinumab in patients with moderate-to-severe plaque psoriasis

Aim/Materials & methods: Few studies have evaluated the influence of pharmacogenetics in psoriatic patients treated with ustekinumab. We evaluated 121 polymorphisms to study a possible association between these SNPs and the response to ustekinumab (PASI75 at 4 months; n = 69). Results/Conclusion: The adjusted results (false discovery rate) showed an association between five SNPs in TNFRSF1A, HTR2A, NFKBIA, ADAM33 and IL13 genes, and poor response to ustekinumab. Furthermore, six SNPs in CHUK, C17orf51, ZNF816A, STAT4, SLC22A4 and Corf72 genes were associated with better response to ustekinumab. However, there was no significant association between response to ustekinumab and SNPs in HLA-C as it has been recently described. Finally, a higher weight was obtained in nonresponders than responders (p = 0.018). Further studies would be necessary to be closer to personalized medicine.