Severe prolonged neutropenia following administration of tocilizumab in a patient affected by COVID-19: a case report and brief review of the literature

A Population Pharmacokinetic Model of Tocilizumab in Kidney Transplant Patients Treated for Chronic Active Antibody-Mediated Rejection: Comparison of Plasma Exposure Between Intravenous and Subcutaneous Administration Schemes

BACKGROUND

Tocilizumab prevents the clinical worsening of chronic active antibody-mediated rejection (CAAMR) in kidney transplant recipients. Following a global shortage of the intravenous pharmaceutical form in 2022, patients were switched from monthly intravenous administration of 8 mg/kg to weekly subcutaneous injection of 162 mg, raising the question of bioequivalence between these schemes of administration.

AIMS

We aimed to compare the areas under the curve (AUC) of tocilizumab in virtual simulations of populations treated with the two administration schemes and to identify the covariates that could contribute to pharmacokinetic variability of tocilizumab in kidney transplant patients with CAAMR who received tocilizumab as salvage treatment.

METHODS

This retrospective monocentric study included 43 kidney transplant patients (202 tocilizumab concentrations) with CAAMR treated with intravenous or subcutaneous tocilizumab between December 2020 and January 2023. We developed a population pharmacokinetic model using nonlinear mixed effects modeling and identified the covariates that could contribute to tocilizumab AUC variability. Monte Carlo simulations were then performed to assess the subcutaneous and intravenous tocilizumab AUC for 0-28 days (M1), 56-84 days (M3), 140-168 days (M6), and 308-336 days (M12). Bioequivalence was defined by SC/IV AUC geometric mean ratios (GMRs) between 0.80 and 1.25.

RESULTS

A two-compartment model with parallel linear and nonlinear elimination best described the concentration-time data. Significant covariates for tocilizumab clearance were body weight, urinary albumin-to-creatinine ratio (ACR), and inflammation status [C-reactive protein (CRP) ≥ 5 mg/L]. The GMR values and their 90% confidence intervals at M3, M6, and M12 were within the 0.8-1.25 margin for equivalence. Conversely, the 90% prediction intervals of the GMR were much wider than the 90% confidence intervals and did not fall within 0.8 and 1.25.

CONCLUSIONS

From month 3 of treatment, the subcutaneous and intravenous tocilizumab administration schemes provided average bioequivalent pharmacokinetic exposure at the population level but not at the individual level. Body weight, inflammation, ACR, and administration scheme should be considered to personalize the dose of tocilizumab for patients with CAAMR. Further studies are required to determine the target of tocilizumab exposure in kidney transplant patients with CAAMR.

Therapeutic Impact of Tocilizumab in the Setting of Severe COVID-19; an Updated and Comprehensive Review on Current Evidence

Introduction

The COVID-19 pandemic caused by SARS-CoV-2 has been the major health concern in 2019 globally. Considering the severity and phase of the disease, various pharmacotherapy schedules were proposed. Here, we set out to provide close-up insights on the clinical utility of Tocilizumab (TCZ), a biologic monoclonal antibody in this regard.

Methods

In this comprehensive review, various databases, including Scopus, PubMed Central, Medline, Embase, Google Scholar, and preprint publishers (med/bioRxiv) were searched until January 30, 2024, according to the keywords and search criteria.

Results

Besides the pros and cons, compelling evidence purported the safety and efficacy of TCZ and indicated that it exhibits great potential to reduce short-term and all-cause (28-30-day) mortality. TCZ significantly drops the adverse events if administered in the right time course (in the inflammatory phase) during critical/severe COVID-19 pneumonia. Despite contradictory results, the benefits of TCZ appear significant, especially in combination with add-on therapies, such as corticosteroids. Although the safety of TCZ is acceptable, solid data is lacking as to its benefits during pregnancy. There are limited data on TCZ combination therapies, such as hemoperfusion, intravenous immunoglobulin (IVIG), simple O2 therapy, vasopressor support, convalescent plasma therapy, and even in vaccinated patients and COVID-19 reinfection, especially in elderly persons. In addition, the impact of TCZ therapy on the long-lasting COVID-19 is unclear.

Conclusion

Personalized medicine based on individual characteristics and pertinent clinical conditions must be considered in the clinicians' decision-making policy. Finally, to mitigate the risk-to-benefit ratio of TCZ, a treatment algorithm, based on available literature and updated national institute of health (NIH) and Infectious Diseases Society of America (IDSA) guidelines, is also proposed.

Association of COVID with Mycosis in General

BACKGROUND

The COVID-19 pandemic caused by SARS-CoV-2 is a respiratory disease which created havoc worldwide, was accompanied by another peculiar, otherwise rare, secondary fungal infection Mucormycosis which was observed at exceptionally high incidence in India during the second wave of COVID-19. The article explores possible links between the two infectious diseases to understand a higher-than-normal occurrence of Mucormycosis in COVID-19 patients. Coronavirus enters the patients through ACE-2 and many other receptors like- NRP-1, TfR, CD-126, and CD-26. Virus bind to cells possessing these receptors and affect their proper functioning, disturbing homeostatic metabolism and resulting in conditions like hyperglycemia, Diabetic Ketoacidosis (DKA), low serum pH, iron overload, anemia, hypoxia, and immunosuppression as explained in the article. All these outcomes provide a very supportive environment for the attack and spread of Mucormycosis fungi. The major receptor for Mucormycosis in humans is the GRP-78. Its expression is upregulated by coronavirus entry and by hyperferritinemia, hyperglycemia, and acidic conditions prevalent in COVID patients, thus providing an easy entry for the fungal species. Upregulation of GRP-78 furthermore damages pancreatic β-cells and intensifies hyperglycemia, showing quite a synergic relationship. Inordinate rise of Mucormycosis cases in India might be explained by facts like- India possessing a large proportion of diabetic patients, emergence of a very deadly strain of coronavirus- Delta strain, higher doses of steroids and antibodies used to treat patients against this strain, overburdened health care services, sudden much higher need of oxygen supply and use of industrial oxygen could explain the Mucormycosis outbreak observed in India during the second wave of COVID-19.

OBJECTIVE

The present review discusses the functional interdependence between COVID-19 and Mucormycosis and summarizes the possible synergic links between COVID and Mucormycosis.

CONCLUSION

The receptors and metabolic pathways affected by COVID-19 result in severe physiological conditions- hyperglycemia, DKA, anemia, iron overload, immunosuppression, and hypoxia. All these conditions not only increase the expression of GRP-78, the major receptor for entry of fungi but also play a crucial role in providing quality media for Mucormycosis fungus to establish and grow. Hence explains the fungal epidemic observed in India during the second wave of COVID-19 in India.

Dilemma of Tocilizumab therapy for a patient with critical COVID‐19 disease and neutropenia: Case report and review of the literature

Infection following SARS‐Co V‐2 leading to COVID‐19 disease is associated with significant morbidity and mortality. The clinical entity, COVID‐19 cytokine storm syndrome (CSS) is a severe immunological manifestation of the disease associated with ominous consequences. Tocilizumab is interleukin‐6 inhibitors that has been shown to hamper the catastrophic outcomes of CCS including the need for mechanical ventilation as well as reduce mortality, but the usage is limited by warnings of reactivation of potential latent infections or immune dysfunctions including severe neutropenia. We describe a case of 39‐year‐old Nepalese male patient with a background of scleritis maintained on azathioprine and rituximab therapy with normal baseline parameters including complete blood count who presented with acute COVID‐19 infection including associated leukopenia as well as severe neutropenia (absolute neutrophil count of 300 cells/µl), then progressed to critical disease culminating into CSS. Based on risks and benefits evaluation, the patient was treated with tocilizumab reinforced with granulocytes‐colony stimulating factor (G‐CSF, Filgrastim) to full recovery and safe outcome including reversal of neutropenia.

Safety profile of COVID-19 drugs in a real clinical setting

PURPOSE

The coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus has affected millions all over the world and has been declared pandemic, as of 11 March 2020. In addition to the ongoing research and development of vaccines, there is still a dire need for safe and effective drugs for the control and treatment against the SARS-CoV-2 virus infection. Numerous repurposed drugs are under clinical investigations whose reported adverse events can raise worries about their safety. The aim of this review is to illuminate the associated adverse events related to the drugs used in a real COVID-19 setting along with their relevant mechanism(s).

METHOD

Through a literature search conducted on PubMed and Google Scholar database, various adverse events suspected to be induced by eight drugs, including dexamethasone, hydroxychloroquine, chloroquine, remdesivir, favipiravir, lopinavir/ritonavir, ivermectin, and tocilizumab, administered in COVID-19 patients in clinical practice and studies were identified in 30 case reports, 3 case series, and 10 randomized clinical trials.

RESULTS

Mild, moderate, or severe adverse events of numerous repurposed and investigational drugs caused by various factors and mechanisms were observed. Gastrointestinal side effects such as nausea, abdominal cramps, diarrhea, and vomiting were the most frequently followed by cardiovascular, cutaneous, and hepatic adverse events. Few other rare adverse drug reactions were also observed.

CONCLUSION

In light of their ineffectiveness against COVID-19 as evident in large clinical studies, drugs including hydroxychloroquine, lopinavir/ritonavir, and ivermectin should neither be used routinely nor in clinical studies. While lack of sufficient data, it creates doubt regarding the reliability of chloroquine and favipiravir use in COVID-19 patients. Hence, these two drugs can only be used in clinical studies. In contrast, ample well-conducted studies have approved the use of remdesivir, tocilizumab, and dexamethasone under certain conditions in COVID-19 patients. Consequently, it is significant to establish a strong surveillance system in order to monitor the proper safety and toxicity profile of the potential anti-COVID-19 drugs with good clinical outcomes.

Specific Interleukin-1 Inhibitors, Specific Interleukin-6 Inhibitors, and GM-CSF Blockades for COVID-19 (at the Edge of Sepsis): A Systematic Review

Sepsis is a syndrome with high mortality, which seriously threatens human health. During the pandemic of coronavirus disease 2019 (COVID-19), some severe and critically ill COVID-19 patients with multiple organ dysfunction developed characteristics typical of sepsis and met the diagnostic criteria for sepsis. Timely detection of cytokine storm and appropriate regulation of inflammatory response may be significant in the prevention and treatment of sepsis. This study evaluated the efficacy and safety of specific interleukin (IL)-1 inhibitors, specific IL-6 inhibitors, and GM-CSF blockades in the treatment of COVID-19 (at the edge of sepsis) patients through systematic review and meta-analysis.

METHODOLOGY

A literature search was conducted on PubMed, EMBASE, Clinical Key, Cochrane Library, CNKI, and Wanfang Database using proper keywords such as "SARS-CoV-2," "Corona Virus Disease 2019," "COVID-19," "anakinra," "tocilizumab," "siltuximab," "sarilumab," "mavrilimumab," "lenzilumab," and related words for publications released until August 22, 2021. Other available resources were also used to identify relevant articles. The present systematic review was performed based on PRISMA protocol.

RESULTS

Based on the inclusion and exclusion criteria, 43 articles were included in the final review. The meta-analysis results showed that tocilizumab could reduce the mortality of patients with COVID-19 (at the edge of sepsis) [randomized controlled trials, RCTs: odds ratio (OR) 0.71, 95%CI: 0.52-0.97, low-certainty evidence; non-RCTs: risk ratio (RR) 0.68, 95%CI: 0.55-0.84, very low-certainty evidence) as was anakinra (non-RCTs: RR 0.47, 95%CI: 0.34-0.66, very low-certainty evidence). Sarilumab might reduce the mortality of patients with COVID-19 (at the edge of sepsis), but there was no statistical significance (OR 0.65, 95%CI: 0.36-1.2, low-certainty evidence). For safety outcomes, whether tocilizumab had an impact on serious adverse events (SAEs) was very uncertain (RCTs: OR 0.87, 95%CI: 0.38-2.0, low-certainty evidence; non-RCTs 1.18, 95%CI: 0.83-1.68, very low-certainty evidence) as was on secondary infections (RCTs: OR 0.71, 95%CI: 0.06-8.75, low-certainty evidence; non-RCTs: RR 1.15, 95%CI: 0.89-1.49, very low-certainty evidence).

CONCLUSIONS

This systematic review showed that tocilizumab, sarilumab, and anakinra could reduce the mortality of people with COVID-19 (at the edge of sepsis), and tocilizumab did not significantly affect SAEs and secondary infections. The current evidence of the studies on patients treated with siltuximab, mavrilimumab, and lenzilumab is insufficient. In order to establish evidence with stronger quality, high-quality studies are needed. Systematic Review Registration: PROSPERO (https://www.crd.york.ac.uk/prospero/), identifier CRD42020226545.

Coronavirus Disease 2019-Associated Invasive Fungal Infection

Coronavirus disease 2019 (COVID-19) can become complicated by secondary invasive fungal infections (IFIs), stemming primarily from severe lung damage and immunologic deficits associated with the virus or immunomodulatory therapy. Other risk factors include poorly controlled diabetes, structural lung disease and/or other comorbidities, and fungal colonization. Opportunistic IFI following severe respiratory viral illness has been increasingly recognized, most notably with severe influenza. There have been many reports of fungal infections associated with COVID-19, initially predominated by pulmonary aspergillosis, but with recent emergence of mucormycosis, candidiasis, and endemic mycoses. These infections can be challenging to diagnose and are associated with poor outcomes. The reported incidence of IFI has varied, often related to heterogeneity in patient populations, surveillance protocols, and definitions used for classification of fungal infections. Herein, we review IFI complicating COVID-19 and address knowledge gaps related to epidemiology, diagnosis, and management of COVID-19-associated fungal infections.