The Role of IL-17 in the Pathogenesis of Psoriasis and Update on IL-17 Inhibitors for the Treatment of Plaque Psoriasis

Evaluation of serial QuantiFERON-TB Gold in tube test results and tuberculosis infection status in patients with psoriasis receiving anti-IL-17 treatment (secukinumab and ixekizumab): Real-world data from a tuberculosis-endemic country

BACKGROUND

In comparison with TNF-α inhibitors, anti-IL-17A agents are considered to have a lower risk of active tuberculosis (TB) or latent TB infection (LTBI) reactivation.

METHODS

In this study, we aimed to evaluate the TB infection status and serial QuantiFERON-TB-Gold in tube test (QFT) results of psoriasis patients using IL-17 inhibitors (secukinumab [SEC] and ixekizumab [IXE]) in a real-world setting from a tuberculosis-endemic country. Patients who used an anti-IL-17 agent for at least 3 months in our follow-up were included in the study. Patients' clinical and demographic features, baseline QFT results and latest QFT results (if any), and TB infection status were noted from the past medical records.

RESULTS

A total of 717 patients, of whom 333 (46.4%) were female, were included in the study. The cumulative exposure time to an anti-IL-17 agent was 14,147 patient-months, 9743 patient-months for SEC and 4404 patient-months for IXE. Also, 459 (SEC = 305/IXE = 154) patients used an anti-IL-17 agent for ≥ 12 months. Of these, 125 had positive baseline QFT results. In all, 334 had negative baseline QFT results. The latest QFT result of 309 was also negative (persistent seronegative group). During follow-up, the QFT results of 10 patients changed from negative to positive (positive seroconversion group). Seven of them were using SEC and three were using IXE, respectively. No case of active TB infection was detected.

CONCLUSION

In our study, the positive seroconversion rate of 10/334 seems high, but this did not translate to active disease. However, closer monitoring may be required, especially in patients with advanced age, the presence of PsA, long disease duration and long anti-IL-17 treatment duration.

Ixekizumab for the treatment of the patients with moderate to severe plaque psoriasis: Clinical data from a real-world experience

Real-life data about any particular treatment is very helpful for clinicians, particularly when managing a chronic disease such as psoriasis. In our study, we aimed to reflect our clinical experience during 48 weeks with an IL-17 antagonist ixekizumab. This study was designed as a retrospective multi-center study. Four tertiary referral centers participated into the study. The patients who did not present to the clinics for 3rd month follow-up were excluded. Data including gender, age, weight, type of psoriasis, additional sites on the body, disease duration, previous treatments, duration of medication of ixekizumab, psoriasis area and severity index scores, previous treatments, and comorbidities, the reasons for drug discontinuation, adverse effects and the patients' naïve or non-naïve status were retrieved from electronic patient folders. Although 267 patients met the inclusion criteria, 28 patients were excluded since they did not present to the clinic for 3rd month follow-up so 239 cases were included mmüne research. We determined significant correlations between naive and non-naive cases about getting PASI 75 and PASI 90 responses for all cases (p = 0.005 and p = 0.028, respectively) and between comorbid and non-comorbid cases about getting PASI 90 and PASI 100 responses for all cases (p = 0.021 and p = 0.029, respectively). When we investigate as female and male patients separately, non-comorbid female cases can achieve PASI 100 response significantly easier than comorbid female patients (p = 0.019). Clinicians can use ixekizumab safely mmüne treatment of their patients with psoriasis and get PASI 75-90-100 responses quickly. Ixekizumab is more effective for naive cases but it may also be a treatment option for biologic experienced patients. The ratio of PASI 75-90-100 responses are better in non-comorbid cases than comorbid patients nevertheless ixekizumab is a quite effective agent mmüne treatment of comorbid cases.

A Review of the Clinical Trial Landscape in Psoriasis: An Update for Clinicians

As our understanding of the pathogenesis of psoriasis has evolved over the past two decades, so has the number of treatment options. The introduction of biologic agents targeting specific cytokines in the interleukin (IL)-23/IL-17 pathway has proven successful in promoting skin clearance among patients. However, their use is often limited owing to cost, parenteral administration, and possible reduced efficacy over time. Topical therapies have also seen limited advancement, with agents such as corticosteroids and vitamin D derivatives remaining the mainstay of treatment, despite side effects limiting their long-term use. New therapeutic agents are needed to improve disease management for patients. In this review, we summarize pipeline and recently approved therapies undergoing clinical trials for psoriasis during a 12-month search period (30 June 2021 to 30 June 2022) using ClinicalTrials.gov. New-generation biologics and oral small molecules in phase II or III development were included, and pivotal data identified through various search modalities (PubMed, conference presentations, etc.) evaluating each drug candidate will be discussed. Topical therapies will also be discussed in line with recent US Food and Drug Administration approvals. As new therapies continue to enter the treatment landscape, long-term data and comparative trials will be needed to better understand their place among existing therapeutic agents.

Roles of IL-25 in Type 2 Inflammation and Autoimmune Pathogenesis

Interleukin-17E (IL-25) is a member of the IL-17 cytokine family that includes IL-17A to IL-17F. IL-17 family cytokines play a key role in host defense responses and inflammatory diseases. Compared with other IL-17 cytokine family members, IL-25 has relatively low sequence similarity to IL-17A and exhibits a distinct function from other IL-17 cytokines. IL-25 binds to its receptor composed of IL-17 receptor A (IL-17RA) and IL-17 receptor B (IL-17RB) for signal transduction. IL-25 has been implicated as a type 2 cytokine and can induce the production of IL-4, IL-5 and IL-13, which in turn inhibits the differentiation of T helper (Th) 17. In addition to its anti-inflammatory properties, IL-25 also exhibits a pro-inflammatory effect in the pathogenesis of Th17-dominated diseases. Here, we review recent advances in the roles of IL-25 in the pathogenesis of inflammation and autoimmune diseases.

Topical Application of BMS-509744, a Selective Inhibitor of Interleukin-2-Inducible T Cell Kinase, Ameliorates Imiquimod-Induced Skin Inflammation in Mice

Psoriasis is an immune disorder-related inflammatory skin disease. Recent studies have suggested a contribution of T cell activation in the pathogenesis of psoriasis. Interleukin-2 (IL-2)-inducible T cell kinase (ITK) regulates T cell activation, including proliferation, and cytokine production. In this study, we investigated the effect of the topically administered selective ITK inhibitor BMS-509744 on imiquimod (IMQ)-induced psoriasis-like skin inflammation in mice. Topically administered BMS-509744 ameliorated IMQ-induced psoriasis-like skin inflammation as shown by decreased skin lesions, epidermal thickening, and cell infiltration into the dermis. These suppressive effects occurred with lower numbers of cluster of differentiation antigen-3⁺ (CD3⁺) T cells and T helper subset 17 (Th17)-related cytokine expression in IMQ-treated skin. IMQ-induced upregulation of proinflammatory cytokine expression was also inhibited by topical application of BMS-509744 in IMQ-treated skin. Our report showed for the first time that topical application of BMS-509744 ameliorated psoriasis-like skin inflammation in mice, which is likely mediated by the inhibition of T cell activation in the skin lesions.

Anti-carbamylated protein and peptide antibodies as potential inflammatory joint biomarkers in the relatives of rheumatoid arthritis patients

OBJECTIVE

Antibodies against carbamylated proteins/peptide (CarP) have been associated with severity in rheumatoid arthritis (RA) patients. However, their role in risk groups, specific targets and relation with periodontal disease (PD) is uncertain yet. The aim of this study was evaluated the association between the levels of anti-CarP with clinical manifestation, human leukocyte antigen (HLA) alleles, periodontal activity markers, PD diagnosis, PD severity, and presence of Porphyromonas gingivalis (P gingivalis) in relatives of patients with RA.

METHODS

One hundred and twenty-four individuals with a family history of RA in first-degree relatives (FDR) and 124 healthy individuals gender- and age-matched, RA activity was assessed. Antibodies against carbamylated protein anti-FCS-Carp and 2 carbamylated peptides of fibrinogen were selected (anti-Ca-Fib2, anti-Ca-Fib3).

RESULTS

Anti-FCS-Carp-positive, anti-Ca-Fib2 and anti-Ca-Fib3 were more frequent in FDR than controls (25.0% vs 14.5%, 34.7% vs 15.3% and 33.1% vs 11.3%, respectively). Anti-FCS-CarP were associated with the HLA-DRB1-SE* 1402 allele (P = .035) and highly sensitive C-reactive protein levels (P = .016), the anti-Ca-Fib2 antibodies were associated with the HLA-DRB1-SE* 1501 allele (P = .03), with non-SE* 0901 allele (P = .01), the anti-Ca-Fib3 was associated with positive rheumatoid factor (P = .0012). The FDR condition was associated with the presence of anti-Ca-Fib3 (odds ratio [OR] =4.7; 95% CI = 1.8-11.7; P = .001) and painful joints (OR = 2.2; 95% CI = 1.01-4.68; P = .045); we also detected an important trend toward the presence of P gingivalis (OR = 1.9; 95% CI = 0.9-3.7; P = .062).

CONCLUSION

The presence of anti-FCS-Carp, anti-Ca-Fib3 and anti-Ca-Fib2 antibodies may have a role for these antibodies as early biomarkers in the development of RA, probably including additional mechanisms related with other non-SE alleles; the anti-peptide antibodies proposed in the present study may represent a simpler way to identify antibodies directed to a specific target.

Cytotoxicity of Saikosaponin A targets HEKa cell through apoptosis induction by ROS accumulation and inflammation suppression via NF-κB pathway

Saikosaponin A (SSA) is a triterpenoid saponin extracted from oriental medicinal plant Radix bupleuri, possessing various biological functions such as anti-inflammatory, immune regulation and anti-virus. This study aimed to explore therapeutic effects of SSA on psoriasis in both vitro and vivo. Our results showed that SSA increased reactive oxygen species (ROS) generation, and decreased mitochondrial membrane potential (MMP) and M5-induced inflammatory cytokines levels in HEKa cells in a dose-dependent manner. In addition, SSA promoted apoptosis and suppressed phosphorylation of NF-κB in vitro, which were restored by the ROS scavenger N-acetylcysteine (NAC). In imiquimod (IMQ)-induced mice, gavage with SSA markedly decreased Psoriasis Area and Severity Index (PASI) score and ameliorated epidermal hyperplasia through inhibition of NF-κB and NLRP3 signaling pathway. In conclusion, our studies demonstrate that SSA induces apoptosis and suppresses inflammation in HEKa cells and ameliorates IMQ-induced psoriasis in mice, making it a therapeutic candidate for psoriasis.

Clinical and histopathological characterization of eczematous eruptions occurring in course of anti IL-17 treatment: a case series and review of the literature

Background: Real-life data often highlight the side effects of certain drugs not previously reported in randomized controlled trials (RCTs).Objective: To describe cutaneous inflammatory eruptions in psoriatic patients treated with an anti IL-17A agent (secukinumab or ixekizumab).Methods: Retrospective analysis of a cohort of patients with chronic plaque psoriasis who started an anti IL-17A agent between September 2016-February 2019 and who developed cutaneous inflammatory eruptions during treatment. A systematic review of similar events reported in the literature was performed.Results: Data of 468 patients were reviewed and 27 cutaneous inflammatory eruptions of 27 (5.8%) patients were collected. The eruptions appeared after a mean of 16.9 ± 17.0 weeks of therapy showing a classical acute eczema in 11 patients (40.7%), an atopic dermatitis-like rash in 11 patients (40.7%) and a psoriasiform eruption in 5 patients (18.5%). Histopathology of 12/27 cases showed epidermal spongiosis in all these variants.Conclusion: We described the clinic-pathologic features of some eczematous eruptions occurring in psoriatic patients, 3-4 months after treatment initiation with an anti IL-17A agent. Further investigations are needed to explain this phenomenon, that might be defined a paradoxical adverse event, based upon the role of IL17 in eczema pathogenesis.

A novel S1P1 modulator IMMH002 ameliorates psoriasis in multiple animal models

Psoriasis is characterized by abnormal proliferation of keratinocytes, as well as infiltration of immune cells into the dermis and epidermis, causing itchy, scaly and erythematous plaques of skin. The understanding of this chronic inflammatory skin disease remains unclear and all available treatments have their limitations currently. Here, we showed that IMMH002, a novel orally active S1P₁ modulator, desensitized peripheral pathogenic lymphocytes to egress signal from secondary lymphoid organs and thymus. Using different psoriasis animal models, we demonstrated that IMMH002 could significantly relieve skin damage as revealed by PASI score and pathological injure evaluation. Mechanistically, IMMH002 regulated CD3⁺ T lymphocytes re-distribution by inducing lymphocytes’ homing, thus decreased T lymphocytes allocation in the peripheral blood and skin but increased in the thymus. Our results suggest that the novel S1P₁ agonist, IMMH002, exert extraordinary capacity to rapidly modulate T lymphocytes distribution, representing a promising drug candidate for psoriasis treatment.

Switching Biologics in the Treatment of Psoriasis: A Multicenter Experience

BACKGROUND/OBJECTIVE

The purpose of our study was to provide evidence on the treatment choices, reasons, and results of switching between biologic agents in treating patients with psoriasis.

METHODS

We conducted a retrospective database search of six tertiary referral centers for pso-riasis patients between January 2007 and May 2019. We analyzed patient and treatment characteristics of all patients in the registry.

RESULTS

We enrolled 427 psoriatic patients treated with biologics, and 145 (34%) required a switch to another biologic. The reasons for discontinuing the first biologic agent were inefficacy (n = 106, 62.4%), adverse events (n = 28, 16.5%), and others (n = 36, 21.2%). At week 12, there was a 67.7% reduction in the Psoriasis Area and Severity Index (PASI) score of patients treated with their first biologic, and 51.4% reduction for the second. A drug survival analysis showed no statistically significant difference between the drug survival of first-line biologic agents, but ustekinumab had the highest survival rate among second-line biologics (log-rank p = 0.010). Multivariate analyses for overall drug discontinuation showed that the occurrence of psoriatic arthritis (OR: 1.883, 95% CI: 1.274-2.782, p = 0.001), nail involvement (OR: 2.334, 95% CI: 1.534-3.552, p < 0.001), and use of concomitant treatment (OR: 2.303, 95% CI: 1.403 -3.780, p = 0.001) are predictors for discontinuation.

CONCLUSION

Discontinuation of treatment was most commonly due to inefficacy. Patients who switched to a different biologic agent showed a similar improvement in PASI scores compared to biologic-naive patients. Switching to a second biologic therapy due to inefficacy or adverse events caused by the first one may improve psoriasis.

Association of genetic polymorphism of interleukin-17A & interleukin-17F with susceptibility of psoriasis

Background & objectives:

Psoriasis is a chronic inflammatory skin disease with unknown aetiology. So far studies have confirmed that interleukins, pro-inflammatory factors and T-cell activation play major role in the development of disease. Interleukin-17 (IL-17) a T helper inflammatory cytokine, was found to be positively correlated with severity of psoriasis. However, the specific mechanism has not been clarified. IL-17A and IL-17F are group members of IL17 family cytokines and found to be located adjacent to one another on the same human chromosome, 6p12. The present study was designed to identify the association between IL-17A and IL-17F gene polymorphism with susceptibility of psoriasis in north Indian population.

Methods:

A total of 166 psoriasis patients and 150 healthy controls were genotyped for IL-17A and IL-17F gene polymorphism by amplification refractory mutation system-polymerase chain reaction method. One single nucleotide polymorphism (SNP) was analysed in IL-17A (rs10484879) and one SNP in IL-17F (rs763780) to look for an association with psoriasis.

Results:

Our study indicated decreased frequency of IL-17A (rs10484879) G allele (51.8 vs. 65.0%), and IL-17F (rs763780) C allele (36.5 vs. 45.7%) in psoriatic patients as compared to healthy controls.

Interpretation & conclusions:

The present findings suggest that IL-17A (rs10484879) G/T and IL-17F (rs763780) C/T gene polymorphisms may contribute in pathogenesis of psoriasis. Further studies need to be done to confirm these findings.

Successful therapy of plaque-type psoriasis with secukinumab in patients with multiple comorbidities treated with previous biologic therapies

PURPOSE

Biologic therapy in psoriatic patients with multiple comorbidities is challenging due to worsening of associated diseases and possible side effects of concomitant medications.

MATERIALS AND METHODS

We describe three patients with multiple comorbidities documenting successful treatment of psoriasis with secukinumab following failure of multiple conventional and biologic DMARDs.

RESULTS

The first case is an obese 59-year-old woman (HBV + with latent tuberculosis) with arterial hypertension and 12-year history of breast cancer. The second is a 45-year-old obese man (HCV + with occult HBV infection on therapy with multiple antipsychotics and taking methadone for opioid dependence), while the last is a 39-year-old man with severe obesity, non-alcoholic hepatosteatosis, and NYHA class II heart failure. All three patients had undergone previous conventional (methotrexate, cyclosporine, retinoids, and phototherapy) and multiple biologic treatments (one or more of the following: adalimumab, ustekinumab, etanercept, infliximab originator, and biosimilar) that were discontinued for inefficacy and/or adverse effects. All patients underwent therapy with secukinumab, which was associated with sustained clinical benefits and no clinically relevant safety findings.

CONCLUSIONS

The present three cases add further evidence that secukinumab is effective and well tolerated in difficult to treat psoriatic patients with multiple comorbidities, namely HBV, latent TBC infection, and hepatic impairment.

IL-17 and limits of success

Interleukin-17 (IL-17) is a potent proinflammatory cytokine that protects a host against fungal and extracellular bacterial infections. On the other hand, excessive or dysregulated production of IL-17 underlines susceptibility to autoimmune disease. Consequently, blocking IL-17 has become an effective strategy for modulating several autoimmune diseases, including multiple sclerosis (MS), psoriasis, and rheumatoid arthritis (RA). Notably, however, IL-17 blockade remains ineffective or even pathogenic against important autoimmune diseases such as inflammatory bowel disease (IBD). Furthermore, the efficacy of IL-17 blockade against other autoimmune diseases, including type 1 diabetes (T1D) is currently unknown and waiting results of ongoing clinical trials. Coming years will determine whether the efficacy of IL-17 blockade is limited to certain autoimmune diseases or can be expanded to other autoimmune diseases. These efforts include new clinical trials aimed at testing second-generation agents with the goal of increasing the efficiency, spectrum, and ameliorating side effects of IL-17 blockade. Here we briefly review the roles of IL-17 in the pathogenesis of selected autoimmune diseases and provide updates on ongoing and recently completed trials of IL-17 based immunotherapies.

Biologics and Small Molecule Agents in Allergic and Immunologic Skin Diseases

PURPOSE OF REVIEW

Biologics and small molecules are key therapeutic options in the treatment of chronic immunologic and allergic skin conditions. By directly targeting innate and inflammatory responses within the skin, including pro-inflammatory cytokines and cellular signaling pathways, these new agents have the potential to counteract the inflammatory cascade responsible for various conditions, including psoriasis and atopic dermatitis. Over the past decade, groundbreaking research identifying key cytokines and receptors involved in the pathogenesis of these diseases has allowed for the development of highly efficacious biologics and small molecules that are associated with unprecedented rates of skin clearance and favorable adverse event profiles.

RECENT FINDINGS

This narrative review evaluates new and upcoming biologic and small molecule agents for the treatment of two allergic/immunologic skin diseases-atopic dermatitis and psoriasis. Numerous small molecules and biologics targeting TNF-α, IL-12/23, IL-17 and IL-17R, and IL-23 are commercially available for the treatment of psoriasis, and newer agents are in various stages of development. Currently, dupilumab, a monoclonal antibody that blocks IL-4R∝, is the only approved biologic for atopic dermatitis. Antibodies targeting IL-13 and IL-31 and small molecules that inhibit Janus kinase and pruritus-mediating receptors are currently being studied in clinical trials. Further investigations into the pathophysiology of atopic dermatitis will likely yield additional therapeutic options in the future. This article reviews recent literature on small molecules and biologics for the treatment of atopic dermatitis and psoriasis.

Secukinumab in moderate-to-severe plaque psoriasis: a multi-center, retrospective, real-life study up to 52 weeks observation

OBJECTIVES

To evaluate efficacy and safety of the anti-IL-17 drug secukinumab in a real-life large cohort of patients with moderate-to-severe plaque psoriasis in Central Italy.

METHODS

Multicenter, retrospective study with an observation period of up to 52 weeks. Efficacy was assessed by Psoriasis Area and Severity Index (PASI) score; clinical and laboratory examinations were performed at baseline and at weeks 4, 12, 24, 36, and 52.

RESULTS

A 90% and a 100% PASI score reduction (PASI90 and PASI100) were reported in 67.5% and 55% of patients at week 12, respectively. A rapid improvement of skin lesions was observed particularly in young patients and in patients naïve to biologics: at week 4, the achievement of PASI90 and PASI100 was higher in younger patients (odds ratio [OR] 0.95, and 0.95; p = 0.003, and 0.005, respectively); PASI90 was achieved by 42.0% of patients naïve to biologics and by 17.0% of patients with prior exposure to biologics (PBT) (OR 0.24; p = 0.001); and PASI100 was reached by 25.5% of naïve patients and 9.8% of PBT (OR 0.28; p = 0.015).The drug was well tolerated.

CONCLUSION

Secukinumab was effective in this real-life analysis, with rapid clinical improvement and long-term maintenance of results.

Percentages of PD-1+CD4+T cells and PD-L1+DCs are increased and sPD-1 level is elevated in patients with immune thrombocytopenia

The present study is to measure the expression of programmed death (PD)-1 / programmed death ligand-1 (PD-L1) negative costimulatory molecules, soluble format sPD-1 in patients with immune thrombocytopenia (ITP), and to investigate their correlation with the secretion of cytokines. A total of 35 patients with ITP were included in the present study. Twenty healthy subjects who received physical examination at our hospital were included as control group. Peripheral blood was collected from all ITP patients and healthy subjects. Flow cytometry was performed to determine the percentages of PD-1+CD4+T cells and PD-L1+DCs in ITP patients and healthy subjects. Enzyme-linked immunosorbent assay was performed to measure the concentrations of interferon (IFN)-γ, interleukin (IL)-17 and sPD-1 in peripheral blood from ITP patients and healthy subjects. Percentages of PD-1+CD4+T cells and PD-L1+DCs in peripheral blood from ITP patients before treatment were significantly higher than that from healthy subjects, but were not different from those after treatment. Serum concentrations of IFN-γ, IL-17 and sPD-1 in ITP patients before treatment were significantly higher than those in healthy subjects, and these concentrations were significantly reduced after treatment. The concentration of sPD-1 was positively correlated with the concentration of IFN-γ, and negatively correlated with platelet count. Percentages of PD-1+CD4+T cells and PD-L1+DCs in ITP patients are higher than those in healthy subjects, but elevated sPD-1 concentration in the blood blocks PD-1/PD-L1 signaling pathway, leading to unaffected Th cell function. Elevated concentrations of IFN-γ and IL-17 in the blood may participate in the occurrence and development of ITP.

ITK and RLK Inhibitor PRN694 Improves Skin Disease in Two Mouse Models of Psoriasis

The chronic and highly prevalent skin disorder psoriasis vulgaris is characterized by a hyperproliferative epidermis and aberrant immune activity. Many studies have highlighted the role of differentiated T lymphocytes in psoriasis progression. Several biologics are currently available that target proinflammatory cytokines produced by T lymphocytes, but the need for improved therapies persists. The small molecule PRN694 covalently binds ITK and RLK, two Tec kinases activated downstream of T-lymphocyte activation, both of which are up-regulated in psoriatic skin. These Tec kinases are involved in signaling cascades mediating T-lymphocyte proliferation, differentiation, and migration and proinflammatory cytokine production. In vitro analysis showed that PRN694 effectively inhibited IL-17A production from murine T helper type 17-differentiated T lymphocytes. Additionally, PRN694 effectively reduced the psoriasis-like phenotype severity and reduced epidermal proliferation and thickness in both the Rac1^V12 and imiquimod mouse models of psoriasis. PRN694 also inhibited CD3⁺ T-cell and γδ T-cell infiltration into skin regions. Inhibition of ITK and RLK attenuated psoriasis-associated signaling pathways, indicating that PRN694 is an effective psoriasis therapeutic.

Spotlight on brodalumab in the treatment of moderate-to-severe plaque psoriasis: design, development, and potential place in therapy

Brodalumab is a novel fully human immunoglobulin G2 monoclonal antibody that antagonizes the interleukin (IL)-17 pathway by binding with high affinity to human IL-17RA. The role of IL-17A in the pathogenesis of psoriasis, as well as the remarkable effectiveness of IL-17 inhibitors in the treatment of moderate-to-severe plaque psoriasis, is well established. The mechanism of action of brodalumab is unique in that it inhibits the IL-17 receptor compared to the two other currently FDA-approved IL-17 inhibitors, secukinumab and ixekizumab, which inhibit the IL-17A molecule itself. The efficacy of brodalumab in the treatment of moderate-to-severe plaque psoriasis has been demonstrated in phase 2 and 3 trials, and subsequently the FDA approved this medication in February 2017. Brodalumab was approved in Japan in July 2016 and approval is pending in Europe. The safety and adverse effects of brodalumab were reviewed across several clinical trials, which, similar to other IL-17 inhibitors, demonstrated increased rates of neutropenia and Candida infections. Brodalumab treatment, similar to ixekizumab and secukinumab, showed no improvement in inflammatory bowel disease patients, and on the contrary, more exacerbations were encountered. Suicidal ideation and behavior events have been reported with brodalumab treatment and are of significant concern. Brodalumab provides another highly effective treatment option for moderate-to-severe plaque psoriasis.

SK, Montero E, Pai HV, Palanivelu DV, Melarkode R, Nair P. T cell activation and differentiation is modulated by a CD6 domain 1 antibody Itolizumab

CD6 is associated with T-cell modulation and is implicated in several autoimmune diseases. We previously demonstrated that Itolizumab, a CD6 domain 1 (CD6D1) specific humanized monoclonal antibody, inhibited the proliferation and cytokine production by T lymphocytes stimulated with anti-CD3 antibody or when co-stimulated with ALCAM. Aberrant IL-17 producing CD4+ helper T-cells (Th17) have been identified as pivotal for the pathogenesis of certain inflammatory autoimmune disorders, including psoriasis. Itolizumab has demonstrated efficacy in human diseases known to have an IL-17 driven pathogenesis. Here, in in vitro experiments we show that by day 3 of human PBMC activation using anti-CD3 and anti-CD28 co-stimulation in a Th17 polarizing milieu, 15-35% of CD4+ T-cells overexpress CD6 and there is an establishment of differentiated Th17 cells. Addition of Itolizumab reduces the activation and differentiation of T cells to Th17 cells and decreases production of IL-17. These effects are associated with the reduction of key transcription factors pSTAT3 and RORγT. Further, transcription analysis studies in these conditions indicate that Itolizumab suppressed T cell activation by primarily reducing cell cycle, DNA transcription and translation associated genes. To understand the mechanism of this inhibition, we evaluated the effect of this anti-human CD6D1 mAb on ALCAM-CD6 as well as TCR-mediated T cell activation. We show that Itolizumab but not its F(ab')2 fragment directly inhibits CD6 receptor hyper-phosphorylation and leads to subsequent decrease in associated ZAP70 kinase and docking protein SLP76. Since Itolizumab binds to CD6 expressed only on human and chimpanzee, we developed an antibody binding specifically to mouse CD6D1. This antibody successfully ameliorated the incidence of experimental autoimmune encephalitis in the mice model. These results position CD6 as a key molecule in sustaining the activation and differentiation of T cells and an important target for modulating autoimmune diseases.