Itolizumab - a humanized anti-CD6 monoclonal antibody with a better side effects profile for the treatment of psoriasis

The CD6/ALCAM pathway promotes lupus nephritis via T cell-mediated responses

T cells are central to the pathogenesis of lupus nephritis (LN), a common complication of systemic lupus erythematosus (SLE). CD6 and its ligand, activated leukocyte cell adhesion molecule (ALCAM), are involved in T cell activation and trafficking. Previously, we showed that soluble ALCAM is increased in urine (uALCAM) of patients with LN, suggesting that this pathway contributes to disease. To investigate, uALCAM was examined in 1038 patients with SLE and LN from 5 ethnically diverse cohorts; CD6 and ALCAM expression was assessed in LN kidney cells; and disease contribution was tested via antibody blockade of CD6 in murine models of SLE and acute glomerulonephritis. Extended cohort analysis offered resounding validation of uALCAM as a biomarker that distinguishes active renal involvement in SLE, irrespective of ethnicity. ALCAM was expressed by renal structural cells whereas CD6 expression was exclusive to T cells, with elevated numbers of CD6+ and ALCAM+ cells in patients with LN. CD6 blockade in models of spontaneous lupus and immune-complex glomerulonephritis revealed significant decreases in immune cells, inflammatory markers, and disease measures. Our data demonstrate the contribution of the CD6/ALCAM pathway to LN and SLE, supporting its use as a disease biomarker and therapeutic target.

Clinical drug therapies and biologicals currently used or in clinical trial to treat COVID-19

The potential emergence of SARS-CoV-2 variants capable of escaping vaccine-generated immune responses poses a looming threat to vaccination efforts and will likely prolong the duration of the COVID-19 pandemic. Additionally, the prevalence of beta coronaviruses circulating in animals and the precedent they have set in jumping into human populations indicates that they pose a continuous threat for future pandemics. Currently, only one therapeutic is approved by the U.S. Food and Drug Administration (FDA) for use in treating COVID-19, remdesivir, although other therapies are authorized for emergency use due to this pandemic being a public health emergency. In this review, twenty-four different treatments are discussed regarding their use against COVID-19 and any potential future coronavirus-associated illnesses. Their traditional use, mechanism of action against COVID-19, and efficacy in clinical trials are assessed. Six treatments evaluated are shown to significantly decrease mortality in clinical trials, and ten treatments have shown some form of clinical efficacy.

A two-arm, randomized, controlled, multi-centric, open-label phase-2 study to evaluate the efficacy and safety of Itolizumab in moderate to severe ARDS patients due to COVID-19

Objective: Efficacy and safety of Itolizumab, an immunomodulatory mAb, in treating moderate-to-severe acute respiratory distress syndrome (ARDS) due to cytokine release in COVID-19 patients was evaluated in a multi-centric, open-label, two-arm, controlled, randomized, phase-2 study.Methods: Patients were randomized (2:1) to Arm-A (best supportive care [BSC]+Itolizumab) and Arm-B (BSC). Primary outcome of interest was reduction in mortality 30-days after enrollment.Results: Thirty-six patients were screened, five treated as first-dose-sentinels and rest randomized, while four patients were screen-failures. Two patients in Arm-A discontinued prior to receiving one complete infusion and were replaced. At end of 1-month, there were three deaths in Arm-B, and none in Arm-A (p = 0.0296; 95% CI = -0.3 [-0.61, -0.08]). At end of study, more patients in Arm-A had improved SpO2 without increasing FiO2 (p = 0.0296), improved PaO2 (p = 0.0296), and reduction in IL-6 (43 vs 212 pg/ml; p = 0.0296) and tumor necrotic factor-α (9 vs 39 pg/ml; p = 0.0253) levels. Transient lymphopenia (Arm-A: 11 patients) and infusion reactions (7 patients) were commonly reported treatment-related safety events.Conclusion: Itolizumab is a promising, safe and effective immunomodulatory therapy for treatment of ARDS due to cytokine release in COVID-19 patients, with survival and recovery-benefit.

Insights into biological therapeutic strategies for COVID-19

The worldwide pandemic of novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that emerged in late December 2019 requires the urgent development of therapeutic options. So far, numerous studies have investigated and uncovered the underlying epidemiology and clinical characteristics of COVID-19 infections in order to develop effective drugs. Compared with antiviral small-molecule inhibitors, biotherapeutics have unique advantages such as fewer side effects by virtue of their high specificity, and thus can be rapidly developed for promising treatments of COVID-19. Here, we summarize potential biotherapeutics and their mechanisms of action, including convalescent plasma, therapeutic antibodies, peptides, engineered ACE2, interferons, cytokine inhibitors, and RNAi-based therapeutics, and discuss in depth the advancements and precautions for each type of biotherapeutics in the treatment of COVID-19.

Approval of Itolizumab for COVID-19: A Premature Decision or Need of The Hour?

Itolizumab is a first-in-class anti-CD6 monoclonal antibody that was initially developed for various cancers and was later developed and approved in India for treatment of moderate to severe chronic plaque psoriasis in 2013. This drug is now being re-purposed for COVID-19. The potential utility of itolizumab in COVID-19, based on its unique mechanism of action in ameliorating cytokine release syndrome (CRS), was proposed first in Cuba with approval of a single-arm clinical trial and expanded access use. Subsequently, a phase II, open-label, randomized, placebo-controlled trial has been conducted in 30 COVID-19 patients in India after receiving regulatory permission. Based on the results, the Indian drug regulatory agency recently approved itolizumab in July 2020 for ‘restricted emergency use’ for the treatment of CRS in moderate to severe acute respiratory distress syndrome (ARDS) due to COVID-19. This has drawn sharp criticism within the scientific community, with the approval being granted on the basis of a relatively small phase II trial, without conduct of a conventional phase III trial, and lacking availability of the claimed supportive real-world evidence in the public domain to date. In a global scenario where finding a successful treatment for COVID-19 is of utmost priority, a biologic agent has been re-purposed and approved with a successfully completed RCT, in a country where cases and mortality due to COVID-19 are growing exponentially. However, instead of welcoming the approval with open arms, many doubts are being raised. This is an issue that needs to be considered and dealt with sensitively, as well as scientifically.

Are We Jumping the Gun with Itolizumab in India? A Situational Analysis from the Pre-COVID Era

Itolizumab, an anti-CD6 monoclonal antibody, has been recently approved for the off-label indication of cytokine release syndrome in the background of COVID-19, by the Drug Controller General of India. However, this drug has not been included in the National Clinical Management Protocol for COVID-19 yet. The limited-to-no experience of the Indian health workforce with the drug urged us to conduct a situational analysis in the pre-COVID era to analyse the degree of use of the drug and the indications for which it has been employed.

Pathophysiology and Potential Therapeutic Candidates for COVID-19: A Poorly Understood Arena

Coronavirus disease 2019 (COVID-19), an acute onset pneumonia caused by a novel Betacoronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in the Wuhan City of China in December 2019 and evolved into a global pandemic. To date, there are no proven drugs or vaccines against this virus. Hence, the situation demands an urgent need to explore all potential therapeutic strategies that can be made available to prevent the disease progression and improve patient outcomes. In absence of clinically proven treatment guidelines, several repurposed drugs and investigational agents are currently being evaluated in clinical trials for their probable benefits in the treatment of COVID-19. These include antivirals (remdesivir, lopinavir/ritonavir, umifenovir, and favipiravir), interferon, antimalarials (chloroquine/hydroxychloroquine), antiparasitic drugs (ivermectin and nitazoxanide), biologics (monoclonal antibodies and interleukin receptor antagonist), cellular therapies (mesenchymal stem cells and natural killer cells), convalescent plasma, and cytokine adsorber. Though several observational studies have claimed many of these agents to be effective based on their in vitro activities and extrapolated evidence from SARS and Middle East respiratory syndrome (MERS) epidemics, the currently available data remains inconclusive because of ill-defined patient selection criteria, small sample size, lack of concurrent controls, and use of intermediary outcomes instead of patient-relevant outcomes. Moreover, there is a need to clearly define the patient populations who warrant therapy and also the timing of initiation of treatment. Understanding the disease pathology responsible for the clinical manifestations of COVID-19 is imperative to identify the potential targets for drug development. This review explains the pathophysiology of COVID-19 and summarizes the potential treatment candidates, which can provide guidance in developing effective therapeutic strategies.

The landscape of novel and complementary targets for immunotherapy: an analysis of gene expression in the tumor microenvironment

Background: Immunotherapies targeting immune checkpoint proteins CTLA-4, PD-1, and PD-L1 have saved lives, but these therapies have only been effective in some patients. Patients positive for expression of immune checkpoint proteins in the tumor microenvironment show better response to immune checkpoint inhibitors. Consequently, knowledge of which genes are consistently expressed in lymphocytes within the tumor microenvironment can convey potentially effective and complementary new immunotherapy targets.

Results: We identified 54 genes that have higher co-expression with the pan T-cell marker CD3E than CTLA4 or PDCD1. In a dataset of 26 patients who received anti-PD-1 therapy, we observed that co-expression between CD3E and PDCD1 was higher among responders than non-responders, supporting our correlation-based approach.

Conclusions: The genes highlighted in these analyses, which include CD6, TIGIT, CD96, and SLAMF6, warrant further investigation of their therapeutic potential.

Methods: We analyzed and ranked genes that were co-expressed with the pan T-cell marker CD3E in 9,601 human tumors, spanning 31 cancer types. To further identify targets that may be complementary to existing PD-1 therapy, we examined and ranked genes with high CD3E co-expression and relatively low PDCD1 co-expression.

Spotlight on itolizumab in the treatment of psoriasis - current perspectives from India

Psoriasis is a chronic, debilitating, immune-mediated, systemic inflammatory disease affecting mainly skin, nails, and joints. Several therapeutic modalities are available depending on the severity of the disease. Long-term use of these drugs results in unwanted effects and toxicities. Recently, itolizumab, a humanized monoclonal immunoglobulin G1 antibody to CD6, has shown appreciable clinical effects and safety profile in patients with moderate-to-severe chronic plaque psoriasis. A literature search was conducted using the keywords "anti-CD6", "psoriasis", "phase trials", "case series", and "case reports". The data from all studies conducted in India on efficacy of itolizumab in psoriasis and published before September 2017 were collected. This article provides an overview of the clinical data obtained in these published articles. Itolizumab has immunomodulatory and anti-inflammatory effects. It is efficacious and provides a good duration of remission, and hence represents a new biological agent that could be added to the therapeutic armamentarium of psoriasis.

Genomic alterations driving psoriasis pathogenesis

Psoriasis is an immune mediated inflammatory skin disease with complex etiology involving interplay between environmental and genetic risk factors as disease initiating event. Enhanced understanding on genetic risk factors, differentially expressed genes, deregulated proteins and pathway-targeted therapeutics have established multiple axis of psoriasis pathogenesis. So far, loci in 424 genes are reported to be associated with psoriasis alongside copy number variations and epigenetic alterations. From clinical perspective, presence of specific genetic trigger(s) in individual psoriasis patient could aid in devising a personalized therapeutic strategy. Therefore, the review presents an updates on reported genomic alterations and their subsequent course of cutaneous inflammations that potentially drive to psoriasis.

CD6 monoclonal antibodies differ in epitope, kinetics and mechanism of action

CD6 is a type I T-cell surface receptor that modulates antigen receptor signalling. Its activity is regulated by binding of its membrane proximal domain (domain 3) to a cell surface ligand, CD166. CD6 monoclonal antibodies (mAbs) specific for the membrane distal domain (domain 1) perturb CD6 function including itolizumab (Alzumab™), which has reached the clinic for treatment of autoimmune disease. We characterized molecular and functional properties of several CD6 mAbs including itolizumab to define potential mechanisms of action. Epitope mapping using the crystal structure of CD6 to design mutants identified two distinct binding sites on different faces of domain 1, one containing residue R77, crucial for MT605 and T12.1 binding and the other, E63, which is crucial for itolizumab and MEM98. Analysis of binding kinetics revealed that itolizumab has a lower affinity compared with other CD6 domain 1 mAbs. We compared potential agonistic (triggering) and antagonistic (blocking) properties of CD6 mAbs in assays where the mechanism of action was well defined. CD6 domain 1 and 3 mAbs were equally effective in triggering interleukin-2 production by a cell line expressing a chimeric antigen receptor containing the extracellular region of CD6. CD6 domain 1 mAbs hindered binding of multivalent immobilized CD166 but were inferior compared with blocking by soluble CD166 or a CD6 domain 3 mAb. Characterization of CD6 mAbs provides an insight into how their functional effects in vivo may be interpreted and their therapeutic use optimized.

Targeting CD6 for the treatment of experimental autoimmune uveitis

OBJECTIVE

CD6 is emerging as a new target for treating many pathological conditions in which T cells are integrally involved, but even the latest data from studies of CD6 gene engineered mice were still contradictory. To address this issue, we studied experimental autoimmune uveitis (EAU), a model of autoimmune uveitis, in wild-type (WT) and CD6 knockout (KO) mice.

METHODS

After EAU induction in WT and CD6 KO mice, we evaluated ocular inflammation and compared retinal antigen-specific T-cell responses using scanning laser ophthalmoscopy, spectral-domain optical coherence tomography, histopathology, and T cell recall assays. Uveitogenic T cells from WT and CD6 KO mice were adoptively transferred into WT naïve mice to confirm the impact of CD6 on T cells. In addition, we immunized CD6 KO mice with recombinant CD6 protein to develop mouse anti-mouse CD6 monoclonal antibodies (mAbs) in which functional antibodies exhibiting cross-reactivity with human CD6 were screened and identified for treatment studies.

RESULTS

In CD6 KO mice with EAU, we found significantly decreased retinal inflammation and reduced autoreactive T-cell responses, and confirmed the impaired uveitogenic capacity of T cells from these mice in an adoptive transfer experiment. Notably, one of these cross-reactive mAbs significantly ameliorated retinal inflammation in EAU induced by the adoptive transfer of uveitogenic T cells.

CONCLUSIONS

Together, these data strongly suggest that CD6 plays a previously unknown, but pivotal role in autoimmune uveitis, and may be a promising new treatment target for this blinding disease. In addition, the newly developed mouse anti-mouse/human CD6 mAbs could be valuable tools for testing CD6-targeted therapies in other mouse models of human diseases.

Itolizumab - A New Biologic for Management of Psoriasis and Psoriatic Arthritis

Psoriasis is a chronic, relapsing, inflammatory, immune-mediated systemic disease with mainly skin and joint manifestations. The available treatment options to cure psoriasis include topical therapy, phototherapy, and biological therapy. Biological therapy has become a promising option due to the rapid action and less adverse effects associated with its use. The newly developed biologic itolizumab is a humanized recombinant anti-CD6 monoclonal antibody of IgG1 isotype that binds to domain 1 of CD6, thereby immunomodulating human lymphocytes without interfering with the binding of CD6 to the activated leukocyte-cell adhesion molecule. In this case series, a total of 5 patients with chronic plaque psoriasis were treated with itolizumab. They exhibited a rapid PASI 75 response after 4 doses of itolizumab infusion. The patients were poor responders to methotrexate and/or cyclosporine therapy for a long time. All infusions were well tolerated by all patients with no adverse reactions or infections during the treatment period. Itolizumab can be a good option for management of psoriasis and psoriatic arthritis.

Itolizumab in the Management of Psoriasis with Metabolic Syndrome

Psoriasis is a chronic, relapsing, inflammatory disease that has been associated with Metabolic Syndrome (MS), a cluster of cardiovascular risk factors mainly hypertension, obesity, diabetes mellitus and hyperlipidemia. A 49-year-old male patient presented with extensive plaque psoriasis from past 13 years. Past medications included methotrexate, PUVA therapy, topical immunosuppressants and corticosteroids. His baseline Psoriasis Area and Severity Index (PASI) score was 39.8. The patient was screened and diagnosed with MS as per Alberti's Criteria (his waist circumference was 100 cm, blood pressure was 160/100 mmHg and High Density Lipoprotein (HDL) was 30 mg/dl). Considering severity of the disease, in this case we used anti-CD6 humanized monoclonal antibody Itolizumab (1.6 mg/kg body weight) to treat psoriasis and concurrent MS. The patient achieved PASI 50 response in six months after treatment of 10 infusions of Itolizumab (First seven doses were given every fortnightly and the last three doses every month). Further, Itolizumab treatment was continued once every three months and PASI 75 response was achieved at the end of 15 months. His PASI score increased to 30.7 after 18 months. Contemplating link between psoriasis and MS due to possibility of overlapping inflammatory pathways, we instructed patient to reduce his weight and prescribed oral tablet metformin 500 mg twice a day. After losing 6 kg weight, his PASI score came down to 22.2 at the end of 21^st month. This suggests that MS was a driving factor in worsening of his psoriasis. Psoriatic patients should be checked simultaneously for co-morbid disease conditions. The report indicates direct association of psoriasis and MS.

CD6 as a potential target for treating multiple sclerosis

CD6 was established as a marker of T cells more than three decades ago, and recent studies have identified CD6 as a risk gene for multiple sclerosis (MS), a disease in which autoreactive T cells are integrally involved. Nevertheless, the precise role of CD6 in regulating T-cell responses is controversial and its significance in the pathogenesis of various diseases remains elusive, partly due to the lack of animals engineered to alter expression of the CD6 gene. In this report, we found that CD6 KO mice showed decreased pathogenic T-cell responses, reduced spinal cord T-cell infiltration, and attenuated disease severity in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. CD6-deficient T cells exhibited augmented activation, but also significantly reduced survival and proliferation after activation, leading to overall decreased Th1 and Th17 polarization. Activated CD6-deficient T cells also showed impaired infiltration through brain microvascular endothelial cell monolayers. Furthermore, by developing CD6 humanized mice, we identified a mouse anti-human CD6 monoclonal antibody that is highly effective in treating established EAE without depleting T cells. These results suggest that (i) CD6 is a negative regulator of T-cell activation, (ii) at the same time, CD6 is a positive regulator of activated T-cell survival/proliferation and infiltration; and (iii) CD6 is a potential new target for treating MS and potentially other T-cell-driven autoimmune conditions.

A Real-World Study to Assess the Effectiveness of Itolizumab in Patients with Chronic Plaque Psoriasis

Background:

While clinical trial data on the efficacy of itolizumab in the management of psoriasis is relatively well documented, data on the effectiveness of this humanized IgG1 monoclonal antibody in real-world settings is sparse.

Aims:

The current study assessed the effectiveness of itolizumab in real-world settings.

Materials and Methods:

This study assessed psoriasis area severity index (PASI), dermatology quality of life index (DLQI), safety, and tolerability data from a registry of itolizumab maintained by Syngene International, Bangalore. Registry data of 155 patients who were prescribed itolizumab at a dose of 1.6 mg/kg every 2 weeks for the first 12 weeks followed by 1.6 mg/kg every 4 weeks for up to 24 weeks for chronic plaque psoriasis.

Results:

In the study, 35.48% completed itolizumab for 12 weeks and 76.59% of these patients achieved PASI 75. Furthermore, 24.51% patients completed the full Itolizumab regimen for 24 weeks, of whom 92.01% patients achieved PASI 75. The mean percent change in DLQI scores at weeks 12 and 24 were 60.19 and 82.72, respectively. Adverse events and infusion reactions noted in the study were generally of mild to moderate severity.

Conclusion:

Itolizumab is a safe and effective option in treatment-compliant patients with chronic plaque psoriasis. Effects of putative compliance-modulators such as cost, route of administration, and delayed onset of action warrant further investigation.

Itolizumab in Psoriasis

A number of biologics is being used for the treatment of psoriasis. Itolizumab is one such agent which has been approved in India. It is an anti-CD6 monoclonal antibody that acts by binding to scavenger receptor cysteine-rich (SRCR) distal domain 1 of CD6. Itolizumab has been found to be safe, with infusion reactions as the most common adverse effect. However, its advantages and disadvantages over other biologicals and immunosuppressants need to be established. Also, its utility in treating other immune-mediated disorders is being explored.

Clinical Outcome of a Novel Anti-CD6 Biologic Itolizumab in Patients of Psoriasis with Comorbid Conditions

Psoriasis is a common, chronic, immune mediated, inflammatory disease of skin characterized by red patches enclosed with white scales and affects 2-3% of people in the world. Topical therapy, phototherapy, and systemic therapy were employed for management of disease from many last decades. However, long term uses of these agents are associated with unwanted effects and toxicities. Recently, Itolizumab has been developed as world's first anti-CD6 humanized monoclonal IgG1 antibody for the management of moderate-to-severe chronic plaque psoriasis in India. Here we are presenting the response indicated by Itolizumab in 7 Indian patients having moderate-to-severe psoriasis with severe comorbidities and who were intolerant/nonresponding to conventional therapies.

Safety and Efficacy of Itolizumab in the Treatment of Psoriasis: A Case Series of 20 Patients

Psoriasis is a common, chronic, relapsing/remitting, immune-mediated skin disease that causes itchy skin with silvery scales. It is characterized by thickened red erythematous plaques covered with silvery scales. Biological therapies have been recently introduced for patients with psoriasis in India. The biological therapies contain protein biomolecules which can be employed to target specific immune or genetic mediator of a pathophysiological process. Here, we share our clinical experience of managing 20 patients with moderate to severe psoriasis by itolizumab a humanized IgG1 monoclonal antibody. Eighteen patients achieved Psoriasis Area and Severity Index (PASI) 75 response after receiving 10 infusion of itolizumab (at the completion of treatment). Out of 18 patients 4 patients had achieved PASI 95 response and 10 patients had achieved PASI 90 response. There was no adverse event reported during the treatment period. Itolizumab was found effective and safe in the treatment of moderate to severe psoriasis patients.