Differential Binding of Sarilumab and Tocilizumab to IL-6Rα and Effects of Receptor Occupancy on Clinical Parameters

Investigating the impact of Tocilizumab, Sarilumab, and Anakinra on clinical outcomes in COVID-19: A systematic review and meta-analysis

Background

Monoclonal antibodies (mAbs) are currently under investigation as a potential therapeutic option for COVID-19. Clinical trials are examining their efficacy in lowering mortality rates and the requirement for mechanical ventilation (MV). It is necessary to conduct a thorough examination of current randomized controlled trials (RCTs) in order to provide more definitive evidence on their effectiveness for COVID-19 patients. This meta-analysis aims to analyze RCT results on the impact of three mAbs (Anakinra, Sarilumab, Tocilizumab) on COVID-19 patient outcomes.

Method

The meta-analysis was conducted in accordance with the PRISMA guidelines. Eligible RCTs were conducted to evaluate the effectiveness of three mAbs in treating patients with COVID-19. These trials were identified by searching various databases up to April 1, 2024. In total, this meta-analysis incorporated 19 trials with a total of 8097 patients. Pooled relative risk and studies' heterogeneity were assessed by statistical analysis, which involved the use of fixed effects models and subgroup analysis.

Result

The administration of mAbs (Tocilizumab, Sarilumab, and Anakinra) showed various results in the management of COVID-19 patients. While the overall pooled data did not reveal a significant reduction in the need for MV, the study found that the use of mAbs was associated with a decreased risk of clinical worsening (pooled relative risk: 0.75, 95 % CI [0.59, 0.94], p = 0.01) and an increased probability of discharging COVID-19 patients by day 28 or 29 (pooled relative risk: 1.17, 95 % CI [1.10, 1.26]). Notably, the subgroup analysis revealed that Tocilizumab had a significant effect in reducing the risk of clinical worsening compared to Sarilumab. Additionally, the analysis of mortality outcomes indicated that the administration of mAbs had the potential to decrease the overall risk of mortality over time (pooled RR: 0.90, 95 % CI [0.83, 0.97], p = 0.01).

Conclusion

In summary, our meta-analysis suggests that mAbs, particularly Tocilizumab, may play a valuable role in managing COVID-19 by reducing the risk of clinical worsening, improving hospital discharge rates, and decreasing mortality.

Plausible mechanism of drug resistance and side-effects of COVID-19 therapeutics: a bottleneck for its eradication

BACKGROUND

COVID-19 pandemic has turned our world upside down by meddling with our normal lives. While there is no definitive drug against SARS-CoV-2, antiviral drugs that are already in the market, are being repurposed against it, could now complete long-term as well as all age-specific investigations, and they are successful in saving millions of lives. Nevertheless, side-effects are emergingly seen in the patients undergoing treatment, and ineffectiveness is increasingly found due to the emerging notorious variants of the virus. Many of them are also facing serious co-infections including black fungus, Zika, and H1N1 virus to name a few.

OBJECTIVES

Therefore, this review highlights both drug resistance, their side-effects, and the significance for proper and long-term clinical trials of all age groups including children.

METHODS

We have explored and proposed the mechanisms of drug resistance that may arise due to the misuse or overuse of drugs based on available experimental reports.

RESULTS

The review provides solutions to the aforesaid issues of drug-resistance and side-effects by providing combination therapies, ancillary treatments, and other preventive strategies that can be useful in preventing drawbacks thereby curbing COVID-19 or similar future infections to maintain our normal lives.

CONCLUSION

COVID-19 and its long-term effects, if any, can be eradicated with strategic and mindful use of related therapeutics in a controlled manner.

Modeling the subcutaneous pharmacokinetics of antibodies co-administered with rHuPH20

Predicting the subcutaneous (SC) pharmacokinetics (PK) of antibodies in humans is challenging, with clinical data currently being the only reliable data source for modeling SC absorption and bioavailability. Recombinant human hyaluronidase PH20 (rHuPH20) is an enzyme that facilitates SC delivery of high-dose, high-volume therapeutics. Numerous monoclonal antibodies have been co-administered SC with rHuPH20 in a clinical setting, establishing an extensive PK database. The goal of this work is to demonstrate how aggregated clinical data can be leveraged in a universal modeling framework for characterizing SC antibody PK, resulting in parameterization that can be used in predictive simulations of new antibodies. Data for 10 individual antibodies co-administered SC with rHuPH20 were obtained from publicly available sources. PK modeling of each antibody was conducted using the same model structure, but uniquely parameterized. The model structure consisted of a two-compartment model to capture linear kinetics, plus a target-binding mechanism to accommodate nonlinear kinetics driven by antibody-target complex formation and elimination. The clinical PK profiles for all antibodies were accurately described using the universal modeling framework. The SC PK parameters of absorption and bioavailability were consistent across the range of antibody and target properties evaluated. SC administration with rHuPH20 yielded a 30% increase in absorption rate on average and similar or better bioavailability. These parameter values can serve as initial conditions for model-based PK predictions for new antibodies co-administered SC with rHuPH20 to enable evaluation of optimal SC dose and schedule regimens prior to and during clinical development.

Structural insights into IL-6 signaling inhibition by therapeutic antibodies

Antibody inhibitors of the interleukin-6 (IL-6) signaling pathway, such as tocilizumab and sarilumab, have been used to treat rheumatoid arthritis, chimeric antigen receptor T cell-induced cytokine storm, and severe COVID-19 pneumonia. Here, we solve the cryogenic electron microscopy structures of sarilumab and tocilizumab in complex with IL-6R to resolutions of 3.2 and 3.3 Å, respectively. These structures reveal that both tocilizumab and sarilumab bind to the D3 domain of IL-6R. The binding surfaces of the two antibodies largely overlap, but the detailed interactions are different. Functional studies of various mutants show results consistent with our structural analysis of the antibodies and IL-6R interactions. Structural comparisons with the IL-6/IL-6R/gp130 complex indicate that sarilumab and tocilizumab probably inhibit IL-6/IL-6R signaling by competing for the IL-6 binding site. In summary, this work reveals the antibody-blocking mechanism of the IL-6 signaling pathway and paves the way for future antibody discovery.

COVID-19 in patients with anemia and haematological malignancies: risk factors, clinical guidelines, and emerging therapeutic approaches

Extensive research in countries with high sociodemographic indices (SDIs) to date has shown that coronavirus disease 2019 (COVID-19) may be directly associated with more severe outcomes among patients living with haematological disorders and malignancies (HDMs). Because individuals with moderate to severe immunodeficiency are likely to undergo persistent infections, shed virus particles for prolonged periods, and lack an inflammatory or abortive phase, this represents an overall risk of morbidity and mortality from COVID-19. In cases suffering from HDMs, further investigation is needed to achieve a better understanding of triviruses and a group of related variants in patients with anemia and HDMs, as well as their treatment through vaccines, drugs, and other methods. Against this background, the present study aimed to delineate the relationship between HDMs and the novel COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Besides, effective treatment options for HDM cases were further explored to address this epidemic and its variants. Therefore, learning about how COVID-19 manifests in these patients, along with exploiting the most appropriate treatments, may lead to the development of treatment and care strategies by clinicians and researchers to help patients recover faster. Video Abstract.

Effect of Anti-Interleukin-6 Agents on Psychopathology in a Sample of Patients with Post-COVID-19 Syndrome: An Observational Study

Interleukin 6 (IL-6) receptor inhibitors tocilizumab and sarilumab have recently been approved for severe coronavirus disease 2019 (COVID-19). They also affect mood, even though their effect on the post-COVID-19 syndrome-related psychopathology still has to be investigated. The aim of this study was to investigate their effect on psychopathology in a sample of patients with post-COVID-19 syndrome. We included 246 patients (34% female, 66% male) aged 18-75 years who had been hospitalized for COVID. Patients were split into those who received anti-IL-6 receptor agents (Anti-IL-6-R, N = 88) and those who did not (Ctrl, N = 158). The former group was further split into those receiving tocilizumab (TOC, N = 67) and those receiving sarilumab (SAR, N = 21). Groups were compared based on clinical characteristics before and during COVID-19 as well as on physical and psychiatric symptoms after COVID-19. Ctrl had less psychiatric and physical symptoms during hospitalization and more post-COVID-19 diarrhea, headache, cough, and dyspnea upon exertion than those receiving IL-6-receptor inhibitors. Ctrl also showed greater difficulties in emotion regulation. These differences were driven by TOC vs. Ctrl, whereas differences between SAR and Ctrl or TOC did not reach significance. IL-6 receptor inhibitors are related to a lower post-COVID-19 illness burden and seem to be effective in emotion regulation. Further research is needed to confirm these findings.

A Bispecific Modeling Framework Enables the Prediction of Efficacy, Toxicity, and Optimal Molecular Design of Bispecific Antibodies Targeting MerTK

Inhibiting MerTK on macrophages is a promising therapeutic strategy for augmenting anti-tumor immunity. However, blocking MerTK on retinal pigment epithelial cells (RPEs) results in retinal toxicity. Bispecific antibodies (bsAbs) containing an anti-MerTK therapeutic and anti-PD-L1 targeting arm were developed to reduce drug binding to MerTK on RPEs, since PD-L1 is overexpressed on macrophages but not RPEs. In this study, we present a modeling framework using in vitro receptor occupancy (RO) and pharmacokinetics (PK) data to predict efficacy, toxicity, and therapeutic index (TI) of anti-MerTK bsAbs. We first used simulations and in vitro RO data of anti-MerTK monospecific antibody (msAb) to estimate the required MerTK RO for in vivo efficacy and toxicity. Using these estimated RO thresholds, we employed our model to predict the efficacious and toxic doses for anti-MerTK bsAbs with varying affinities for MerTK. Our model predicted the highest TI for the anti-MerTK/PD-L1 bsAb with an attenuated MerTK binding arm, which was consistent with in vivo efficacy and toxicity observations. Subsequently, we used the model, in combination with sensitivity analysis and parameter scans, to suggest an optimal molecular design of anti-MerTK bsAb with the highest predicted TI in humans. Our prediction revealed that this optimized anti-MerTK bsAb should contain a MerTK therapeutic arm with relatively low affinity, along with a high affinity targeting arm that can bind to a low abundance target with slow turnover rate. Overall, these results demonstrated that our modeling framework can guide the rational design of bsAbs.

A phase 3 randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of sarilumab in patients with giant cell arteritis

BACKGROUND

Giant cell arteritis (GCA) is primarily treated with glucocorticoids (GCs), which have substantial toxicity. Tocilizumab, an interleukin-6-receptor inhibitor (IL-6Ri), showed beneficial effects in GCA, leading to its approval. This study investigated the efficacy and safety of sarilumab (another IL-6Ri) in GCA.

METHODS

This Phase 3, double-blind study comprised a 52-week treatment period and a 24-week follow-up phase. Eligible GCA patients were randomized to receive sarilumab 200 mg (SAR200 + 26W) or 150 mg (SAR150 + 26W) with a 26-week GC taper, or placebo with a 52-week (PBO + 52W) or 26-week (PBO + 26W) GC taper. The primary efficacy endpoint was sustained remission (SR) at week 52. Additional endpoints were SR at week 24, cumulative GC dose, and safety. The study was discontinued prematurely due to protracted recruitment timelines, because of the impact of COVID-19. Therefore, only descriptive statistics were summarized.

RESULTS

Of the planned 360 subjects, only 83 were randomized and 36 were included in the week 52 analysis. At week 52, 46% (n = 6/13) of patients in SAR200 + 26W, 43% (n = 3/7) in SAR150 + 26W, 30% (n = 3/10) in PBO + 52W, and 0 (n = 0/6) in PBO + 26W taper groups achieved SR. Sensitivity analyses, excluding acute-phase reactants from the SR definition, showed similar results for SAR groups, but 60% (n = 6/10) in PBO + 52W and 17% (n = 1/6) in PBO + 26W taper groups achieved SR at week 52. Similar findings were noted at week 24. The proportions of patients who adhered to GC taper from week 12 through week 52 in each group were as follows: 46% (n = 6/13, SAR200 + 26W), 43% (n = 3/7, SAR150 + 26W), 60% (n = 6/10, PBO + 52W), and 33% (n = 2/6, PBO + 26W). The median actual cumulative GC dose received in the SAR200 + 26W group was lower than other groups. Most patients (80-100%) experienced treatment-emergent adverse events, with similar incidences reported across groups.

CONCLUSIONS

Owing to the small sample size due to the early termination, it is difficult to draw clear conclusions from this study. There were no unexpected safety findings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03600805. Registered on July 26, 2018.

The role of inflammation in autoimmune disease: a therapeutic target

Autoimmune diseases (AIDs) are immune disorders whose incidence and prevalence are increasing year by year. AIDs are produced by the immune system's misidentification of self-antigens, seemingly caused by excessive immune function, but in fact they are the result of reduced accuracy due to the decline in immune system function, which cannot clearly identify foreign invaders and self-antigens, thus issuing false attacks, and eventually leading to disease. The occurrence of AIDs is often accompanied by the emergence of inflammation, and inflammatory mediators (inflammatory factors, inflammasomes) play an important role in the pathogenesis of AIDs, which mediate the immune process by affecting innate cells (such as macrophages) and adaptive cells (such as T and B cells), and ultimately promote the occurrence of autoimmune responses, so targeting inflammatory mediators/pathways is one of emerging the treatment strategies of AIDs. This review will briefly describe the role of inflammation in the pathogenesis of different AIDs, and give a rough introduction to inhibitors targeting inflammatory factors, hoping to have reference significance for subsequent treatment options for AIDs.

Drug retention of biologics and Janus kinase inhibitors in patients with rheumatoid arthritis: the ANSWER cohort study

OBJECTIVES

This multicentre retrospective study in Japan aimed to assess the retention of biological disease-modifying antirheumatic drugs and Janus kinase inhibitors (JAKi), and to clarify the factors affecting their retention in a real-world cohort of patients with rheumatoid arthritis.

METHODS

The study included 6666 treatment courses (bDMARD-naïve or JAKi-naïve cases, 55.4%; tumour necrosis factor inhibitors (TNFi) = 3577; anti-interleukin-6 receptor antibodies (aIL-6R) = 1497; cytotoxic T lymphocyte-associated antigen-4-Ig (CTLA4-Ig) = 1139; JAKi=453 cases). The reasons for discontinuation were divided into four categories (ineffectiveness, toxic adverse events, non-toxic reasons and remission); multivariate Cox proportional hazards modelling by potential confounders was used to analyse the HRs of treatment discontinuation.

RESULTS

TNFi (HR=1.93, 95% CI: 1.69 to 2.19), CTLA4-Ig (HR=1.42, 95% CI: 1.20 to 1.67) and JAKi (HR=1.29, 95% CI: 1.03 to 1.63) showed a higher discontinuation rate due to ineffectiveness than aIL-6R. TNFi (HR=1.28, 95% CI: 1.05 to 1.56) and aIL-6R (HR=1.27, 95% CI: 1.03 to 1.57) showed a higher discontinuation rate due to toxic adverse events than CTLA4-Ig. Concomitant use of oral glucocorticoids (GCs) at baseline was associated with higher discontinuation rate due to ineffectiveness in TNFi (HR=1.24, 95% CI: 1.09 to 1.41), as well as toxic adverse events in JAKi (HR=2.30, 95% CI: 1.23 to 4.28) and TNFi (HR=1.29, 95%CI: 1.07 to 1.55).

CONCLUSIONS

TNFi (HR=1.52, 95% CI: 1.37 to 1.68) and CTLA4-Ig (HR=1.14, 95% CI: 1.00 to 1.30) showed a higher overall drug discontinuation rate, excluding non-toxicity and remission, than aIL-6R.

Add-on effectiveness of methotrexate or iguratimod in patients with rheumatoid arthritis exhibiting an inadequate response to Janus kinase inhibitors: The ANSWER cohort study

OBJECTIVES

This multicenter, retrospective study evaluated the effectiveness of add-on methotrexate (MTX) or iguratimod (IGU) in patients with rheumatoid arthritis exhibiting an inadequate response to Janus kinase inhibitors (JAKis).

METHODS

Forty-five patients were treated with new additional MTX (n = 22) or IGU (n = 23) and followed for 6 months. Patients' background is as follows: age, 59.2 years; disease activity score of 28 joints with C-reactive protein (DAS28-CRP), 3.4; clinical disease activity index, 15.7; biological disease-modifying antirheumatic drug (DMARD)-switched cases, 77.8%; first JAKi cases, 95.6%; and JAKi treatment: tofacitinib (n = 25), baricitinib (n = 17), upadacitinib (n = 2), and peficitinib (n = 1) for 9.6 months.

RESULTS

Thirty-five patients continued the combination therapy for 6 months without a significant change in concomitant glucocorticoid or other conventional synthetic DMARDs. DAS28-CRP (MTX, 3.6 to 2.6, p < 0.05; IGU, 3.3 to 2.1, p < 0.001) and clinical disease activity index (MTX, 16.7 to 8.8, p < 0.05; IGU, 14.6 to 6.5, p < 0.01) improved significantly from baseline. Using the 2019 European League Against Rheumatism criteria, 45.4% (MTX) and 39.1% (IGU) achieved moderate or good response and 40.9% (MTX) and 39.1% (IGU) achieved American College of Rheumatology 20% improvement criteria.

CONCLUSIONS

Adding MTX or IGU to inadequate responders of JAKi can be considered as a complementary treatment.

Cancer and COVID-19: unravelling the immunological interplay with a review of promising therapies against severe SARS-CoV-2 for cancer patients

Cancer patients, due to their immunocompromised status, are at an increased risk for severe SARS-CoV-2 infection. Since severe SARS-CoV-2 infection causes multiple organ damage through IL-6-mediated inflammation while stimulating hypoxia, and malignancy promotes hypoxia-induced cellular metabolic alterations leading to cell death, we propose a mechanistic interplay between both conditions that results in an upregulation of IL-6 secretion resulting in enhanced cytokine production and systemic injury. Hypoxia mediated by both conditions results in cell necrosis, dysregulation of oxidative phosphorylation, and mitochondrial dysfunction. This produces free radicals and cytokines that result in systemic inflammatory injury. Hypoxia also catalyzes the breakdown of COX-1 and 2 resulting in bronchoconstriction and pulmonary edema, which further exacerbates tissue hypoxia. Given this disease model, therapeutic options are currently being studied against severe SARS-COV-2. In this study, we review several promising therapies against severe disease supported by clinical trial evidence-including Allocetra, monoclonal antibodies (Tixagevimab-Cilgavimab), peginterferon lambda, Baricitinib, Remdesivir, Sarilumab, Tocilizumab, Anakinra, Bevacizumab, exosomes, and mesenchymal stem cells. Due to the virus's rapid adaptive evolution and diverse symptomatic manifestation, the use of combination therapies offers a promising approach to decrease systemic injury. By investing in such targeted interventions, cases of severe SARS-CoV-2 should decrease along with its associated long-term sequelae and thereby allow cancer patients to resume their treatments.

Sarilumab plus standard of care vs standard of care for the treatment of severe COVID-19: a phase 3, randomized, open-labeled, multi-center study (ESCAPE study)

Background

Among interleukin-6 inhibitors suggested for use in COVID-19, there are few robust evidences for the efficacy of sarilumab. Herein, we evaluated the efficacy and safety of sarilumab in severe COVID-19.

Methods

In this phase 3, open-labeled, randomized clinical trial, conducted at 5 Italian hospitals, adults with severe COVID-19 pneumonia (excluding mechanically ventilated) were randomized 2:1 to receive intravenous sarilumab (400 mg, repeatable after 12 h) plus standard of care (SOC) (arm A) or to continue SOC (arm B). Randomization was web-based. As post-hoc analyses, the participants were stratified according to baseline inflammatory parameters. The primary endpoint was analysed on the modified Intention-To-Treat population, including all the randomized patients who received any study treatment (sarilumab or SOC). It was time to clinical improvement of 2 points on a 7-points ordinal scale, from baseline to day 30. We used Kaplan Meier method and log-rank test to compare the primary outcome between two arms, and Cox regression stratified by clinical center and adjusted for severity of illness, to estimate the hazard ratio (HR). The trial was registered with EudraCT (2020-001390-76).

Findings

Between May 2020 and May 2021, 191 patients were assessed for eligibility, of whom, excluding nine dropouts, 176 were assigned to arm A (121) and B (55). At day 30, no significant differences in the primary endpoint were found (88% [95% CI 81-94] in arm A vs 85% [74-93], HR 1.07 [0.8-1.5] in arm B; log-rank p = 0.50). After stratifying for inflammatory parameters, arm A showed higher probability of improvement than B without statistical significance in the strata with C reactive protein (CRP) < 7 mg/dL (88% [77-96] vs 79% [63-91], HR 1.55 [0.9-2.6]; log-rank p = 0.049) and in the strata with lymphocytes <870/mmc (90% [79-96]) vs (73% [55-89], HR 1.53 [0.9-2.7]; log-rank p = 0.058). Overall, 39/121 (32%) AEs were reported in arm A and 14/55 (23%) in B (p = 0.195), while serious AEs were 22/121 (18%) and 7/55 (11%), respectively (p = 0.244). There were no treatment-related deaths.

Interpretation

The efficacy of sarilumab in severe COVID-19 was not demonstrated both in the overall and in the stratified for severity analysis population. Exploratory analyses suggested that subsets of patients with lower CRP values or lower lymphocyte counts might have had benefit with sarilumab treatment, but this finding would require replication in other studies. The relatively low rate of concomitant corticosteroid use, could partially explain our results.

Funding

This study was supported by INMI "Lazzaro Spallanzani" Ricerca Corrente Linea 1 on emerging and reemerging infections, funded by Italian Ministry of Health.

Could the fibromyalgia syndrome be triggered or enhanced by COVID-19?

Fibromyalgia (FM) is a complex disease with an uncertain aetiology and intricate pathophysiology. Although its genesis is not fully explained, potential environmental factors, such as viral infections might trigger FM or worsen patients' clinical outcomes. The SARS-CoV-2 virus may affect central and peripheral nervous systems, leading to musculoskeletal, neurological, and psychological disturbances. These symptoms might persist at least 12 months beyond the recovery, often referred to as post-COVID syndrome, which resembles FM syndrome. In this sense, we argued the potential consequences of COVID-19 exclusively on FM syndrome. First, we have described post-COVID syndrome and its painful symptoms. Afterwards, we argued whether FM syndrome could be triggered or enhanced by COVID-19 infection or by numerous and persistent stressors imposed daily by the pandemic setting (isolation, uncertainty, depression, mental stress, generalized anxiety, and fear of the virus). In addition, we have demonstrated similarities between pathophysiological mechanisms and cardinal symptoms of FM and COVID-19, speculating that SARS-CoV-2 might represent a critical mediator of FM or an exacerbator of its symptoms once both syndromes share similar mechanisms and complaints. Therefore, pharmacologic and non-pharmacological approaches commonly used to treat FM could serve as strategic therapies to attenuate painful and neurological manifestations of post-COVID syndrome. Although it is still theoretical, clinicians and researchers should be alert of patients who develop symptoms similar to FM or those who had their FM symptoms increased post-COVID to manage them better.

Should We Interfere with the Interleukin-6 Receptor During COVID-19: What Do We Know So Far?

Severe manifestations of COVID-19 consist of acute respiratory distress syndrome due to an initially local reaction leading to a systemic inflammatory response that results in hypoxia. Many therapeutic approaches have been attempted to reduce the clinical consequences of an excessive immune response to viral infection. To date, systemic corticosteroid therapy is still the most effective intervention. More recently, new hope has emerged with the use of interleukin (IL)-6 receptor inhibitors (tocilizumab and sarilumab). However, the great heterogeneity of the methodology and results of published studies obfuscate the true value of this treatment, leading to a confusing synthesis in recent meta-analyses, and the persistence of doubts in terms of patient groups and the appropriate time to treat. Moreover, their effects on the anti-infectious or pro-healing response are still poorly studied. This review aims to clarify the potential role of IL-6 receptor inhibitors in the treatment of severe forms of COVID-19.

TriTECM: A tetrafunctional T-cell engaging antibody with built-in risk mitigation of cytokine release syndrome

Harnessing the innate power of T cells for therapeutic benefit has seen many shortcomings due to cytotoxicity in the past, but still remains a very attractive mechanism of action for immune-modulating biotherapeutics. With the intent of expanding the therapeutic window for T-cell targeting biotherapeutics, we present an attenuated trispecific T-cell engager (TCE) combined with an anti- interleukin 6 receptor (IL-6R) binding moiety in order to modulate cytokine activity (TriTECM). Overshooting cytokine release, culminating in cytokine release syndrome (CRS), is one of the severest adverse effects observed with T-cell immunotherapies, where the IL-6/IL-6R axis is known to play a pivotal role. By targeting two tumour-associated antigens, epidermal growth factor receptor (EGFR) and programmed death ligand 1 (PD-L1), simultaneously with a bispecific two-in-one antibody, high tumour selectivity together with checkpoint inhibition was achieved. We generated tetrafunctional molecules that contained additional CD3- and IL-6R-binding modules. Ligand competition for both PD-L1 and IL-6R as well as inhibition of both EGF- and IL-6-mediated signalling pathways was observed. Furthermore, TriTECM molecules were able to activate T cells and trigger T-cell-mediated cytotoxicity through CD3-binding in an attenuated fashion. A decrease in pro-inflammatory cytokine interferon γ (IFNγ) after T-cell activation was observed for the TriTECM molecules compared to their respective controls lacking IL-6R binding, hinting at a successful attenuation and potential modulation via IL-6R. As IL-6 is a key player in cytokine release syndrome as well as being implicated in enhancing tumour progression, such molecule designs could reduce side effects and cytotoxicity observed with previous TCEs and widen their therapeutic windows.

The affinity of antigen-binding domain on the antitumor efficacy of CAR T cells: Moderate is better

The overall efficacy of chimeric antigen receptor modified T cells (CARTs) remain limited in solid tumors despite intensive studies that aim at targeting multiple antigens, enhancing migration, reducing tonic signaling, and improving tumor microenvironment. On the other hand, how the affinity and engaging kinetics of antigen-binding domain (ABD) affects the CART's efficacy has not been carefully investigated. In this article, we first analyzed 38 published solid tumor CART trials and correlated the response rate to their ABD affinity. Not surprisingly, majority (25 trials) of the CARTs utilized high-affinity ABDs, but generated merely 5.7% response rate. In contrast, 35% of the patients treated with the CARTs built from moderate-affinity ABDs had clinical responses. Thus, CARTs with moderate-affinity ABDs not only have less off-target toxicity, but also are more effective. We then reviewed the effects of ABD affinity on the biology and function of CARTs, providing further evidence that moderate-affinity ABDs may be better in CART development. In the end, we propose that a fast-on/fast-off (high Kon and Koff ) kinetics of CART-target engagement in solid tumor allow CARTs to generate sufficient signaling to kill tumor cells without being driven to exhaustion. We believe that studying the ABD affinity and the kinetics of CART-tumor interaction may hold a key to designing effective CARTs for solid tumors.

Treatment strategies of COVID-19: A rheumatology perspective

The clinical progression of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) to critical illness is associated with a systemic and uncontrolled inflammatory response of the innate and adaptive immunity with the release of a plethora of proinflammatory cytokines termed "cytokine storm". In the absence of an effective treatment, many off-label agents from the armamentarium of rheumatology are used. Here, from the perspective of a rheumatologist, we will discuss the current therapeutic strategies in critically ill patients with SARS-CoV-2 pneumonia. Thus, we will discuss the agents that aim to target viral entry and its replication into the host cell and those focusing and targeting the inflammatory response. In this setting, many agents have been used with promising results but, not all have been approved by the International Authorities and Institutions. In the first step (viral entry), SARS-CoV-2 monoclonal antibodies and remdesivir have been approved to be used and, in the second step, corticosteroids along with interleukin-6 inhibitors, or Janus Kinase inhibitors are currently used.

Reduced fixed dose tocilizumab 400 mg IV compared to weight-based dosing in critically ill patients with COVID-19: A before-after cohort study

Background

Interleukin-6 inhibitors reduce mortality in severe COVID-19. British Columbia began using tocilizumab 8 mg/kg (maximum 800 mg) in January 2021 in critically ill patients with COVID-19, but due to drug shortages, decreased dosing to 400 mg IV fixed dose in April 2021. The aims of this study were twofold: to compare physiological responses and clinical outcomes of these two strategies, and examine the cost-effectiveness of treating all patients with 400 mg versus half the patients with 8 mg/kg and the other half without tocilizumab.

Methods

This was a single-centre, before-after cohort study of critically ill COVID-19 patients treated with tocilizumab, and a control cohort treated with dexamethasone only. Physiological responses and clinical outcomes were compared between patients receiving both doses of tocilizumab and those receiving dexamethasone only. We built a decision tree model to examine cost-effectiveness.

Findings

152 patients were included; 40 received tocilizumab 8 mg/kg, 59 received 400 mg and 53 received dexamethasone only. Median CRP fell from 103 mg/L to 5.2 mg/L, 96 mg/L to 6.8 mg/L and from 81.3 mg/L to 48 mg/L in the 8 mg/kg, 400 mg tocilizumab, and dexamethasone only groups, respectively. 28-day mortality was 5% (n=2) vs 8% (n=5) vs 13% (n=7), with no significant difference in all pair-wise comparison. At an assumed willingness-to-pay threshold of $50,000 Canadian per life-year, utilizing 400 mg for all patients rather than 8 mg/kg for half the patients is cost-effective in 51.6% of 10,000 Monte Carlo simulations.

Interpretation

Both doses of tocilizumab demonstrated comparable reduction of inflammation with similar 28-day mortality. Without consideration of equity, the net monetary benefits of providing 400 mg tocilizumab to all patients are comparable to 8 mg/kg to half the patients. In the context of ongoing drug shortages, fixed-dose 400 mg tocilizumab may be a practical, feasible and economical option.

Funding

This work was supported by a gift donation from Hsu & Taylor Family to the VGH Foundation, and the Yale Bernard G. Forget Scholarship.

Effects of the Interleukin-6 Receptor Blocker Sarilumab on Metabolic Activity and Differentiation Capacity of Primary Human Osteoblasts

Interleukin (IL-) 6 is a key factor in the inflammatory processes of rheumatoid arthritis. Several biologic agents target the IL-6 signaling pathway, including sarilumab, a monoclonal antibody that blocks the IL-6 receptor and inhibits IL-6-mediated cis- and trans-signaling. A careful analysis of the IL-6 signaling blockade should consider not only inflammatory processes but also the regenerative functions of IL-6. The purpose of this study was to investigate whether inhibition of the IL-6 receptors affects differentiation of human primary osteoblasts (hOB). The effects of sarilumab on viability and the differentiation capacity in unstimulated osteoblasts as well as after stimulation with various IL-6 and sIL6-R concentrations were determined. Sarilumab treatment alone did not affect the differentiation or induction of inflammatory processes in hOB. However, the significant induction of alkaline phosphatase activity which was observed after exogenous IL-6/sIL-6R costimulation at the highest concentrations was reduced back to baseline levels by the addition of sarilumab. The IL-6 receptor blockade also decreased gene expression of mediators required for osteogenesis and bone matrix maintenance. Our results demonstrate that concomitant administration of the IL-6 receptor blocker sarilumab can inhibit IL-6/sIL-6R-induced osteogenic differentiation.

Management of hepatitis B virus reactivation due to treatment of COVID-19

The world has made significant progress in developing novel treatments for COVID-19 since the pandemic began. Some treatments target the patient's dysregulated inflammatory response during COVID-19 infection and may cause hepatitis B reactivation (HBVr) in patients with current or past hepatitis B virus (HBV) infection. This review summarizes the risk and management of HBVr due to different treatments of COVID-19 in patients who have current or past HBV infection. Abnormal liver function tests are common during COVID-19 infection. Current evidence suggests that current or past HBV infection is not associated with an increased risk of liver injury and severe disease in COVID-19 patients. Among patients who received high-dose corticosteroids, various immunosuppressive monoclonal antibodies and inhibitors of Janus kinase, the risk of HBVr exists, especially among those without antiviral prophylaxis. Data, however, remain scarce regarding the specific use of immunosuppressive therapies in COVID-19 patients with HBV infection. Some results are mainly extrapolated from patients receiving the same agents in other diseases. HBVr is a potentially life-threatening event following profound immunosuppression by COVID-19 therapies. Future studies should explore the use of immunosuppressive therapies in COVID-19 patients with HBV infection and the impact of antiviral prophylaxis on the risk of HBVr.

Sarilumab in adults hospitalised with moderate-to-severe COVID-19 pneumonia (CORIMUNO-SARI-1): An open-label randomised controlled trial

Background

Patients with COVID-19 pneumonia can have increased inflammation and elevated cytokines, including interleukin (IL)-6, which might be deleterious. Thus, sarilumab, a high-affinity anti-IL-6 receptor antibody, might improve the outcome of patients with moderate-to-severe COVID-19 pneumonia.

Methods

We did a multicentric, open-label, Bayesian randomised, adaptive, phase 2/3 clinical trial, nested within the CORIMUNO-19 cohort, to test a superiority hypothesis. Patients 18 years or older hospitalised with COVID-19 in six French centres, requiring at least 3L/min of oxygen but without ventilation assistance and a WHO Clinical Progression Scale [CPS] score of 5 were enrolled. Patients were randomly assigned (1:1) via a web-based system, according to a randomisation list stratified on centre and with blocks randomly selected among 2 and 4, to receive usual care plus 400 mg of sarilumab intravenously on day 1 and on day 3 if clinically indicated (sarilumab group) or usual care alone (usual care group). Primary outcomes were the proportion of patients with WHO-CPS scores greater than 5 on the 10-point scale on day 4 and survival without invasive or non-invasive ventilation at day 14. This completed trial is closed to new participants and is registered with ClinicalTrials.gov, NCT04324073.

Findings

165 patients were recruited from March 27 to April 6, 2020, and 148 patients were randomised (68 patients to the sarilumab group and 80 to the usual care group) and followed up for 90 days. Median age was 61·7 years [IQR 53·0–71·1] in the sarilumab group and 62·8 years [56·0–71·7] in the usual care group. In the sarilumab group 49 (72%) of 68 were men and in the usual care group 59 (78%) of 76 were men. Four patients in the usual care group withdrew consent and were not analysed. 18 (26%) of 68 patients in the sarilumab group had a WHO-CPS score greater than 5 at day 4 versus 20 (26%) of 76 in the usual care group (median posterior absolute risk difference 0·2%; 90% credible interval [CrI] −11·7 to 12·2), with a posterior probability of absolute risk difference greater than 0 of 48·9%. At day 14, 25 (37%) patients in the sarilumab and 26 (34%) patients in the usual care group needed ventilation or died, (median posterior hazard ratio [HR] 1·10; 90% CrI 0·69–1·74) with a posterior probability HR greater than 1 of 37·4%. Serious adverse events occurred in 27 (40%) patients in the sarilumab group and 28 (37%) patients in the usual care group (p=0·73).

Interpretation

Sarilumab treatment did not improve early outcomes in patients with moderate-to-severe COVID-19 pneumonia. Further studies are warranted to evaluate the effect of sarilumab on long-term survival.

Funding

Assistance publique—Hôpitaux de Paris

Advances in clinical outcomes: what we have learned during the COVID-19 pandemic

Our understanding of risk factors and interventions influencing outcomes from coronavirus disease 2019 (COVID-19) has continued to evolve, revealing advances emerging from hypotheses formed at the start of the pandemic. Epidemiologic studies have shown that asthma control, rather than a diagnosis of asthma, is a determinant of COVID-19 severity. Clinical outcomes in patients with primary immunodeficiencies, even in those with impaired cellular immunity, are variable. IL-6 has emerged as a reliable biomarker of COVID-19 severity, and large clinical trials have shown the potential for improving outcomes through inhibition of IL-6 signaling in some patients. Studies of genetic risk factors for severe COVID-19 have also revealed the importance of interferon homeostasis in the defense against severe acute respiratory syndrome coronavirus 2. Because COVID-19 vaccines constitute the primary tool for ending this pandemic, strategies have been developed to address potential allergic and immune-mediated reactions. Here, we discuss advances in our understanding of COVID-19 risk factors and outcomes within the context of allergic and immunologic mechanisms.

SARS-CoV-2 Spike Protein-Induced Interleukin 6 Signaling Is Blocked by a Plant-Produced Anti-Interleukin 6 Receptor Monoclonal Antibody

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the current COVID-19 pandemic, has caused more than 4.5 million deaths worldwide. Severe and fatal cases of COVID-19 are often associated with increased proinflammatory cytokine levels including interleukin 6 (IL-6) and acute respiratory distress syndrome. In this study, we explored the feasibility of using plants to produce an anti-IL-6 receptor (IL-6R) monoclonal antibody (mAb) and examined its utility in reducing IL-6 signaling in an in vitro model, which simulates IL-6 induction during SARS-CoV-2 infection. The anti-IL6R mAb (IL6RmAb) was quickly expressed and correctly assembled in Nicotiana benthamiana leaves. Plant-produced IL6RmAb (pIL6RmAb) could be enriched to homogeneity by a simple purification scheme. Furthermore, pIL6RmAb was shown to effectively inhibit IL-6 signaling in a cell-based model system. Notably, pIL6RmAb also suppressed IL-6 signaling that was induced by the exposure of human peripheral blood mononuclear cells to the spike protein of SARS-CoV-2. This is the first report of a plant-made anti-IL-6R mAb and its activity against SARS-CoV-2-related cytokine signaling. This study demonstrates the capacity of plants for producing functionally active mAbs that block cytokine signaling and implies their potential efficacy to curb cytokine storm in COVID-19 patients.

Immunogenicity of sarilumab and impact on safety and efficacy in Japanese patients with rheumatoid arthritis: analysis of two Phase 3 randomised clinical trials

OBJECTIVES

To describe the immunogenicity profile of sarilumab in Japanese patients with rheumatoid arthritis (RA).

METHODS

Patients enrolled in the KAKEHASI and HARUKA studies were included in our analysis. In these studies, patients received sarilumab 150 mg or 200 mg every 2 weeks for 52 or 28 weeks in combination with methotrexate (MTX) (KAKEHASI), or for 52 weeks as monotherapy or in combination with non-MTX conventional synthetic disease-modifying anti-rheumatic drugs (HARUKA). Anti-drug antibodies (ADAs) and neutralising antibodies (NAbs) were assessed in the pooled population.

RESULTS

Positive ADA assay responses occurred in 10/149 (7.1%) patients treated with sarilumab 150 mg and 13/185 (7.0%) patients treated with sarilumab 200 mg, with persistent responses in 2 (1.4%) and 4 (2.2%) patients, respectively. Peak ADA titre was 30. No patients treated with the 150 mg dose and one patient (0.5%) treated with the 200 mg dose exhibited NAbs. There was no evidence of an association between ADA formation and hypersensitivity reactions or reduced efficacy.

CONCLUSIONS

ADAs, which occurred at a low frequency and titre, did not affect the safety or efficacy of sarilumab 150 or 200 mg administered as monotherapy or combination therapy in Japanese patients with RA in the KAKEHASI or HARUKA studies.

Anti-Inflammatory Therapeutic Approaches to Prevent or Delay Post-Traumatic Osteoarthritis (PTOA) of the Knee Joint with a Focus on Sustained Delivery Approaches

Inflammation plays a central role in the pathogenesis of knee PTOA after knee trauma. While a comprehensive therapy capable of preventing or delaying post-traumatic osteoarthritis (PTOA) progression after knee joint injury does not yet clinically exist, current literature suggests that certain aspects of early post-traumatic pathology of the knee joint may be prevented or delayed by anti-inflammatory therapeutic interventions. We discuss multifaceted therapeutic approaches that may be capable of effectively reducing the continuous cycle of inflammation and concomitant processes that lead to cartilage degradation as well as those that can simultaneously promote intrinsic repair processes. Within this context, we focus on early disease prevention, the optimal timeframe of treatment and possible long-lasting sustained delivery local modes of treatments that could prevent knee joint-associated PTOA symptoms. Specifically, we identify anti-inflammatory candidates that are not only anti-inflammatory but also anti-degenerative, anti-apoptotic and pro-regenerative.

Treatment or Prophylaxis against Hepatitis B Virus Infection in Patients with Rheumatic Disease Undergoing Immunosuppressive Therapy: An Update

Chronic hepatitis B virus (HBV) flares or reactivations are serious causes of morbidity or mortality in rheumatologic patients undergoing immunosuppressive therapy. The recent insights in the pathogenesis of rheumatic diseases led to the use of new immunosuppressive therapies indicated in case of failure, partial response, or intolerance of conventional synthetic disease-modifying anti-rheumatic drugs. Based on these premises, this review examines and discusses the main rheumatologic treatments that could require the initiation of prophylactic treatment or close monitoring of occult HBV infection in patients beginning antiviral therapy at the first signs of HBV reactivation, or antiviral treatment in chronic HBV-infected patients. We searched for relevant studies published in the last five years. Studies suggested that the presence of HBV infection is common in rheumatic patients and HBV reactivation during these immunosuppressant treatments is quite frequent in these kinds of patients. Therefore, before starting an immunosuppressive therapy, patients should be screened for HBsAg, anti-HBs, and anti-HBc and, on the basis of markers positivity, they should be carefully characterized for HBV infection phases. In conclusion, screening of HBV infection in patients undergoing immunosuppressive therapy with subsequent HBV monitoring, prophylaxis or treatment consistently reduces the risk of clinical consequences.

Novel Coronavirus Disease 2019 (COVID-19) and Cytokine Storms for More Effective Treatments from an Inflammatory Pathophysiology

The Novel Coronavirus Disease 2019 (COVID-19) has swept the world and caused a global pandemic. SARS-CoV-2 seems to have originated from bats as their reservoir hosts over time. Similar to SARS-CoV, this new virus also exerts its action on the human angiotensin-converting enzyme 2. This action causes infections in cells and establishes an infectious disease, COVID-19. Against this viral invasion, the human body starts to activate the innate immune system in producing and releasing proinflammatory cytokines such as IL-6, IL-1β, IL-8, TNF-α, and other chemokines, such as G-CSF, IP10 and MCPl, which all develop and increase the inflammatory response. In cases of COVID-19, excessive inflammatory responses occur, and exaggerated proinflammatory cytokines and chemokines are detected in the serum, resulting in cytokine release syndrome or cytokine storm. This causes coagulation abnormalities, excessive oxidation developments, mitochondrial permeability transition, vital organ damage, immune system failure and eventually progresses to disseminated intravascular coagulation and multiple organ failure. Additionally, the excessive inflammatory responses also cause mitochondrial dysfunction due to progressive and persistent stress. This damages cells and mitochondria, leaving products containing mitochondrial DNA and cell debris involved in the excessive chronic inflammation as damage-associated molecular patterns. Thus, the respiratory infection progressively leads to disseminated intravascular coagulation from acute respiratory distress syndrome, including vascular endothelial cell damage and coagulation-fibrinolysis system disorders. This condition causes central nervous system disorders, renal failure, liver failure and, finally, multiple organ failure. Regarding treatment for COVID-19, the following are progressive and multiple steps for mitigating the excessive inflammatory response and subsequent cytokine storm in patients. First, administering of favipiravir to suppress SARS-CoV-2 and nafamostat to inhibit ACE2 function should be considered. Second, anti-rheumatic drugs (monoclonal antibodies), which act on the leading cytokines (IL-1β, IL-6) and/or cytokine receptors such as tocilizumab, should be administered as well. Finally, melatonin may also have supportive effects for cytokine release syndrome, resulting in mitochondrial function improvement. This paper will further explore these subjects with reports mostly from China and Europe.