Anti-CD6 mAbs for the treatment of psoriasis

Long-term therapy with itolizumab is safe and effective for patients with moderate to severe psoriasis: Results from an expanded-access program

Itolizumab is a humanized monoclonal antibody that selectively targets the CD6-ALCAM pathway. This article reports on the safety and efficacy of itolizumab in the treatment of moderate-to-severe plaque psoriasis in a clinical study conducted in Cuba in the setting of an expanded-access program (EAP). The study included 84 patients who had previously received conventional anti-psoriatic systemic therapies but were either intolerant, had an inadequate response, or had contraindications to these therapies. It consisted of multiple phases, including a 12-week induction phase, a 40-week maintenance phase, and a 24-week off-treatment follow-up phase, using either a 0.4 or 1.6 mg/Kg dose. The results showed that itolizumab monotherapy was safe and effective during 52 weeks of continuous treatment and the subsequent 24 follow-up weeks. Itolizumab treatment resulted in a significant improvement (PASI 75) in 80 % of patients at the end of the induction phase, and this effect was sustained till week 52 during the maintenance phase. Moreover, 24 weeks after treatment stopped nearly two-thirds of patients still showed a PASI ≥ 75. The observed effects were dose-dependent, with 1.6 mg/kg being the most convenient dose. This study further supports the strategy of targeting the CD6-ALCAM signaling pathway for the treatment of psoriasis and the use of itolizumab as a valuable asset in the armamentarium of anti-psoriasis drugs.

CD6-targeted antibody-drug conjugate as a new therapeutic agent for T cell lymphoma

T cell lymphomas (TCL) are heterogeneous, aggressive, and have few available targeted therapeutics. In this study, we determined that CD6, an established T cell marker, was expressed at high levels on almost all examined TCL patient specimens, suggesting that CD6 could be a new therapeutic target for this life-threatening blood cancer. We prepared a CD6-targeted antibody-drug conjugate (CD6-ADC) by conjugating monomethyl auristatin E (MMAE), an FDA-approved mitotic toxin, to a high-affinity anti-human CD6 monoclonal antibody (mAb). In contrast to both the unconjugated anti-CD6 mAb, and the non-binding control ADC, CD6-ADC potently and selectively killed TCL cells in vitro in both time- and concentration-dependent manners. It also prevented the development of tumors in vivo in a preclinical model of TCL. More importantly, systemic or local administration of the CD6-ADC or its humanized version, but not the controls, significantly shrank established tumors in the preclinical mouse model of TCL. These results suggest that CD6 is a novel therapeutic target in TCLs and provide a strong rationale for the further development of CD6-ADC as a promising therapy for patients with these potentially fatal lymphoid neoplasms.

Modulation of Dietary Fatty Acids in an Open-Label Study Improves Psoriasis and Dampens the Inflammatory Activation Status

Obesity and high abdominal fat mass are risk factors for developing the chronic inflammatory skin disease psoriasis. They are associated with increased incidence, prevalence and severity of the disease. A positive effect of weight loss on psoriasis activity has been shown in several studies. Obesity-related factors such as the dysregulation of glucose and lipid metabolism, the activation of adipose tissue and resultant persistent low-grade inflammation have been discussed as links of obesity and inflammatory diseases. Recently, we demonstrated a critical role of free fatty acids (FFAs) in obesity-mediated exacerbation of psoriatic skin inflammation in both mice and humans. In the present study, we translated these findings into a therapeutic intervention. An open-label study focusing on the dietary reduction of FFAs was conducted in patients with mild-to-moderate plaque psoriasis, and disease severity and serum markers of inflammation were analyzed. Here, we show that such a dietary intervention improves psoriatic disease activity independently of weight loss. Diet-related metabolic changes, such as a reduction in saturated free fatty acids (SFAs), may thus be more important than weight loss itself. Moreover, dietary intervention inhibited the overall pro-inflammatory activation status in patients, as shown by analysis of serum inflammatory parameters using the Olink platform. From our pilot study, we conclude that dietary intervention focusing on SFA reduction has the capacity to reduce disease activity and general inflammatory status in psoriasis patients.

Autoantibodies - enemies, and/or potential allies?

Autoantibodies are well known as potentially highly harmful antibodies which attack the host via binding to self-antigens, thus causing severe associated diseases and symptoms (e.g. autoimmune diseases). However, detection of autoantibodies to a range of disease-associated antigens has enabled their successful usage as important tools in disease diagnosis, prognosis and treatment. There are several advantages of using such autoantibodies. These include the capacity to measure their presence very early in disease development, their stability, which is often much better than their related antigen, and the capacity to use an array of such autoantibodies for enhanced diagnostics and to better predict prognosis. They may also possess capacity for utilization in therapy, in vivo. In this review both the positive and negative aspects of autoantibodies are critically assessed, including their role in autoimmune diseases, cancers and the global pandemic caused by COVID-19. Important issues related to their detection are also highlighted.

Th1 and Th17 cells are resistant towards T cell activation-induced downregulation of CD6

BACKGROUND

The cell surface molecule CD6 is a modulator of T cell receptor (TCR) signaling. Recently, it has been reported that CD6 is downregulated on CD4+ T cells following T cell activation. This mechanism could limit the efficacy of anti-CD6 therapeutical antibodies.

METHODS

We analyzed CD6 expression on activated and non-activated Th1 cells and Th17 cells by flow cytometry.

RESULTS

Our experiments confirmed a significant downregulation of CD6 on IFNγ- and IL17-negative CD4+ T cells from healthy individuals and from patients with rheumatoid arthritis following T cell activation with anti-CD3 and anti-CD28 antibodies. In contrast, CD6 expression remained stable on activated Th17 cells and Th1 cells.

CONCLUSIONS

Th1 and Th17 cells are resistant towards T cell activation-induced downregulation of CD6. These findings are relevant for the future development of CD6 targeting therapies and show that CD6 expression is differentially regulated in CD4+ T cell subsets.

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.

Soluble CD5 and CD6: Lymphocytic Class I Scavenger Receptors as Immunotherapeutic Agents

CD5 and CD6 are closely related signal-transducing class I scavenger receptors mainly expressed on lymphocytes. Both receptors are involved in the modulation of the activation and differentiation cell processes triggered by clonotypic antigen-specific receptors present on T and B cells (TCR and BCR, respectively). To serve such a relevant immunomodulatory function, the extracellular region of CD5 and CD6 interacts with soluble and/or cell-bound endogenous counterreceptors but also microbial-associated molecular patterns (MAMPs). Evidence from genetically-modified mouse models indicates that the absence or blockade of CD5- and CD6-mediated signals results in dysregulated immune responses, which may be deleterious or advantageous in some pathological conditions, such as infection, cancer or autoimmunity. Bench to bedside translation from transgenic data is constrained by ethical concerns which can be overcome by exogenous administration of soluble proteins acting as decoy receptors and leading to transient “functional knockdown”. This review gathers information currently available on the therapeutic efficacy of soluble CD5 and CD6 receptor infusion in different experimental models of disease. The existing proof-of-concept warrants the interest of soluble CD5 and CD6 as safe and efficient immunotherapeutic agents in diverse and relevant pathological conditions.