Role of Biological Agents in the Treatment of SARS-CoV-2-Associated Multisystem Inflammatory Syndrome in Children

Infectious Diseases Society of America Guidelines on the Treatment and Management of Patients With COVID-19 (September 2022)

There are many pharmacologic therapies that are being used or considered for treatment of coronavirus disease 2019 (COVID-19), with rapidly changing efficacy and safety evidence from trials. The objective was to develop evidence-based, rapid, living guidelines intended to support patients, clinicians, and other healthcare professionals in their decisions about treatment and management of patients with COVID-19. In March 2020, the Infectious Diseases Society of America (IDSA) formed a multidisciplinary guideline panel of infectious disease clinicians, pharmacists, and methodologists with varied areas of expertise to regularly review the evidence and make recommendations about the treatment and management of persons with COVID-19. The process used a living guideline approach and followed a rapid recommendation development checklist. The panel prioritized questions and outcomes. A systematic review of the peer-reviewed and grey literature was conducted at regular intervals. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the certainty of evidence and make recommendations. Based on the most recent search conducted on 31 May 2022, the IDSA guideline panel has made 32 recommendations for the treatment and management of the following groups/populations: pre- and postexposure prophylaxis, ambulatory with mild-to-moderate disease, and hospitalized with mild-to-moderate, severe but not critical, and critical disease. As these are living guidelines, the most recent recommendations can be found online at: https://idsociety.org/COVID19guidelines. At the inception of its work, the panel has expressed the overarching goal that patients be recruited into ongoing trials. Since then, many trials were conducted that provided much-needed evidence for COVID-19 therapies. There still remain many unanswered questions as the pandemic evolved, which we hope future trials can answer.

The Therapy of SARS-CoV-2 Infection in Children

The impact of SARS-CoV-2 infections in children has fortunately been lower than what has been seen in adults. However, even previously healthy children have developed severe disease, sometimes with subsequent mortality, and those who are infants or adolescents, are from racial and ethnic minority groups, or have certain chronic conditions are at higher risk of these outcomes. During the pandemic, extensive studies of therapeutic agents, including antivirals and immunomodulators, were conducted in adults. Few trials included children, and most were in older children and adolescents. Thus, the potential benefits of therapies in children must be extrapolated from adult evidence. Despite these limitations, advisory committees of the National Institute of Health (NIH), the Infectious Disease Society of America (IDSA), and the Pediatric Infectious Diseases Society (PIDS) were constituted, and expert consensus guidelines were developed. This review provides a synthesis of those comprehensive recommendations for therapy in children. These address treatment during the early infectious period with antiviral agents, including remdesivir and nirmatrelvir/ritonavir, as well as treatment in the later period of immune dysregulation with corticosteroids and immunomodulators. In addition, the therapeutic approach for multisystem inflammatory syndrome in children (MIS-C), also referred to as Pediatric Inflammatory Multisystem Syndrome temporally associated with SARS-CoV-2 (PIMS-TS), is also provided.

Tocilizumab for Severe COVID-19 Infection and Multisystem Inflammatory Syndrome in Adults and Children

Coronavirus disease 2019 (COVID-19) rapidly emerged as a global pandemic, placing imminent stress and burden on healthcare resources and workers worldwide. Many patients who present with a severe COVID-19 infection are at high risk of developing severe acute respiratory distress syndrome (ARDS), leading to a vast number of patients requiring mechanical ventilation and a high mortality rate. Similar to Middle East respiratory syndrome, COVID-19 demonstrates an initial viral replication phase that manifests as a variety of symptoms typically flu-like in nature, followed by a profound inflammatory response leading to rapid production of cytokines and uncontrolled inflammation. There have also been many cases of COVID-19 in pediatric patients presenting with elevated inflammatory markers and multisystem involvement labeled as a multisystem inflammatory syndrome (MIS-C) by the world health organization (WHO). The recent treatment of systemic inflammatory response to COVID-19 targets the secondary phase involving cytokine release syndrome. The detrimental effects of IL-6 can be profound and elevated levels are associated with a higher mortality rate and mechanical ventilation. Tocilizumab is an IL-6 inhibitor most widely investigated to target cytokine storm syndrome. Since June 2021, the FDA enacted an emergency use authorization for tocilizumab in the treatment of COVID-19. Several clinical trials have investigated tocilizumab combined with corticosteroids for treating severe ARDS associated with COVID-19. An increasing amount of evidence suggests that targeting the cytokine storm syndrome related to COVID-19 can lead to improved outcomes, especially in those patients requiring mechanical ventilation and with a critical illness. Additional studies are warranted to further look at the positive effects of tocilizumab in the COVID-19 population while additionally defining possible adverse effects.

Use of Intravenous Anakinra for Management of Pediatric Cytokine Storm Syndromes at an Academic Medical Center

Background: Off-label intravenous (IV) route of anakinra is increasingly recognized to enable higher and faster maximal plasma concentrations than subcutaneous route for treatment of cytokine storm syndromes. Objective: To describe off-label indications of IV anakinra, corresponding dosing and safety profiles, particularly during the coronavirus disease 19 (COVID-19) pandemic. Methods: A retrospective, single-cohort study was conducted at an academic medical center to evaluate use of IV anakinra in hospitalized pediatric patients (age ≤21 years). Institutional Review Board review was considered exempt. The primary endpoint was the primary indication(s) for IV anakinra. The key secondary endpoints were dosing of IV anakinra, previous immunomodulatory therapies, and adverse events. Results: Of 14 pediatric patients, 8 (57.1%) received IV anakinra for treatment of multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19, whereas 3 and 2 were treated for hemophagocytic lymphohistiocytosis (HLH) and flares of systemic onset juvenile idiopathic arthritis (SoJIA), respectively. The initial dosing regimen of IV anakinra for MIS-C associated with COVID-19 was a median dose of 2.25 mg/kg/dose with a median dosing interval of 12 hours for a median initial treatment duration of 3.5 days. Eleven (78.6%) patients received previous immunomodulatory therapies (IV immune globulin [n = 10; 71.4%] and steroids [n = 9; 64.3%]). No adverse drug events were documented. Conclusion: IV anakinra was used off-label for treatment of MIS-C associated with COVID-19, HLH and SoJIA flares in critically ill patients with no adverse drug events documented. This study helped ascertain the off-label indications of IV anakinra and corresponding patient characteristics.

Recent research on the application of biologics in the treatment of multisystem inflammatory syndrome in children after SARS-CoV-2 infection

Multisystem inflammatory syndrome in children (MIS-C) is a type of hyperinflammatory symptoms similar to Kawasaki disease after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and is commonly observed in children aged 8-10 years. Primary therapeutic medications for MIS-C are intravenous immunoglobulins and glucocorticoids. It has been reported that biologics, such as IL-1 receptor antagonist anakinra, IL-6 receptor antagonist tocilizumab, and TNF-α receptor antagonist infliximab, can be used as an option for critically ill patients. This article elaborates on the mechanism of action of the above biologics and discusses the efficacy and safety biologics in the treatment of MIS-C after SARS-CoV-2 infection, in order to provide methods for the treatment of MIS-C with severe symptoms.

Anakinra treatment in multisystemic inflammatory syndrome in children (MIS-C) associated with COVID-19

OBJECTIVE

The study aimed to report the efficacy and safety of anakinra treatment in patients with the refractory multisystemic inflammatory syndrome in children (MIS-C).

METHODS

This is a cross-sectional retrospective study consisting of pediatric patients diagnosed with MIS-C who were treated with anakinra.

RESULTS

Among the 378 patients diagnosed with MIS-C, 82 patients (21.6%) who were treated with anakinra were included in the study. The median age of patients was 115 (6-214) months. The median duration of hospitalization was 15 (6-42) days. Sixty patients (73.1%) were admitted to the pediatric intensive care unit. Patients were treated with a median dose of 2.7 mg/kg/day anakinra concomitant with IVIG and steroids. Intravenous anakinra was applied to 12 patients while 70 patients received it subcutaneously. Twenty-eight patients required high dose (4-10 mg/kg/day) anakinra. The median day of anakinra initiation was 2 (1-14) days and the median duration of anakinra use was 7 (1-41) days. No injection site reactions were observed while elevated transaminase levels were detected in 13 patients. Seventy-three patients (89.1%) were discharged without any sequela or morbidity. Seven patients (1.8%) died. Abnormal echocardiographic findings continued in two patients (2.4%) (coronary artery dilatation in one, low ejection fraction in one) at discharge and became normal on the 2^nd month.

CONCLUSION

Based on the results of the study, anakinra was associated with clinical improvements and was safe for most patients with refractory MIS-C.

Multisystem inflammatory syndrome in children related to COVID-19: Data from a Mexican national referral children's hospital

OBJECTIVES

To describe characteristics of patients with the pediatric inflammatory multisystem syndrome, temporally associated with SARS-CoV-2 (PIMS-TS)/multisystem inflammatory syndrome in children (MIS-C) and to identify factors associated with admission to the pediatric intensive care unit (PICU) in the Mexican children without coronavirus disease 2019 (COVID-19) vaccination.

METHODS

This was a cross-sectional study performed at Hospital Infantil de Mexico Federico Gomez, a referral children's hospital in Mexico. The study included all cases that met the criteria for PIMS-TS/MIS-C, unvaccinated, between March 2020 and January 2022. The primary outcome was the admission to PICU. Associations of PICU admission with demographic and clinical variables were estimated using logistic regression analyses.

RESULTS

We identified a total of 90 cases, with a median age of 7.5 years old, 47 (52.2%) girls. A previously healthy status was recorded in 76 (85%) children. All patients had positive PCR, serology test, or COVID-19 exposure. PICU admission was reported in 41 (45.6%) children. No deaths were reported. Patients received as treatment only corticosteroids in 53.3% of the cases. In univariable analyses, baseline factors associated with PICU admission were older age, hypotension or shock, positive PCR test, hypoalbuminemia, elevated procalcitonin, ferritin, and lymphopenia. Age, shock at admission, and hypoalbuminemia remained independently associated in the multivariable analysis adjusted by gender and previously healthy status.

CONCLUSION

We found a high proportion of previously healthy children in patients with PIMS-TS/MIS-C in our center. Critical care attention was received by nearly half of the children. The main treatment used was steroids. Age, shock at admission, and hypoalbuminemia were factors associated with PICU admission.

Case Report: Ciclosporin A for Refractory Multisystem Inflammatory Syndrome in Children

Multisystem inflammatory syndrome in children (MIS-C) is a new syndrome involving the development of severe dysfunction in multiple organs after severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. Because the pathophysiology of MIS-C remains unclear, a treatment strategy has not yet been established. We experienced a 12-year-old boy who developed MIS-C at 56 days after SARS-CoV-2 infection and for whom ciclosporin A (CsA) was effective as a third-line treatment. He had a high fever on day 1, and developed a rash on the trunk, swelling in the cervical region, and palmar erythema on day 2. On days 3, he developed conjunctivitis and lip redness, and fulfilled the criteria for classical Kawasaki disease (KD). Although intravenous immunoglobulin infusion (IVIG) was started on day 4, fever persisted and respiratory distress and severe abdominal pain developed. On day 5, because he fulfilled the criteria for MIS-C, methylprednisolone pulse was started for 3 days as a second-line treatment. However, he did not exhibit defervescence and the symptoms continued. Therefore, we selected CsA as a third-line treatment. CsA was so effective that he became defervescent and his symptoms disappeared. In order to clarify the relationship with treatment and the change of clinical conditions, we examined the kinetics of 71 serum cytokines to determine their relationships with his clinical course during the three successive treatments. We found that CsA suppressed macrophage-activating cytokines such as, IL-12(p40), and IL-18 with improvement of his clinical symptoms. CsA may be a useful option for additional treatment of patients with MIS-C refractory to IVIG + methylprednisolone pulse.

Algorithm for the diagnosis and management of the multisystem inflammatory syndrome in children associated with COVID-19

OBJECTIVE

Although the initial reports of COVID-19 cases in children described that children were largely protected from severe manifestations, clusters of paediatric cases of severe systemic hyperinflammation and shock related to severe acute respiratory syndrome coronavirus 2 infection began to be reported in the latter half of April 2020. A novel syndrome called "multisystem inflammatory syndrome in children" (MIS-C) shares common clinical features with other well-defined syndromes, including Kawasaki disease, toxic shock syndrome and secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome. Our objective was to develop a protocol for the evaluation, treatment and follow-up of patients with MIS-C.

METHODS

The protocol was developed by a multidisciplinary team. We convened a multidisciplinary working group with representation from the departments of paediatric critical care, cardiology, rheumatology, surgery, gastroenterology, haematology, immunology, infectious disease and neurology. Our protocol and recommendations were based on the literature and our experiences with multisystem inflammatory syndrome in children. After an agreement was reached and the protocol was implemented, revisions were made on the basis of expert feedback.

CONCLUSION

Children may experience acute cardiac decompensation or other organ system failure due to this severe inflammatory condition. Therefore, patients with severe symptoms of MIS-C should be managed in a paediatric intensive care setting, as rapid clinical deterioration may occur. Therapeutic approaches for MIS-C should be tailored depending on the patients' phenotypes. Plasmapheresis may be useful as a standard treatment to control hypercytokinemia in cases of MIS-C with severe symptoms. Long-term follow-up of patients with cardiac involvement is required to identify any sequelae of MIS-C.