Safety and Tolerability of Monoclonal Antibody Therapies for Treatment of COVID-19 in Pediatric Patients.

There is a little data regarding safety or efficacy of monoclonal antibody treatment for mild-to-moderate COVID-19 in pediatric patients despite it being frequently used in adults. This retrospective study of 17 patients with mild-to-moderate COVID-19 who received monoclonal antibody therapy found that the treatment was well tolerated, safe, and may be effective in halting progression to severe disease.

The first reported case of COVID-19, a respiratory disease caused by a novel coronavirus SARS-CoV-2, occurred in December 2019. Since its discovery, the virus has caused a catastrophic pandemic, infected >155 million and resulted in >3 million deaths worldwide.[1] While the pediatric population has not been affected by primary COVID-19 to the same degree as adults, there is substantial morbidity for those with acute disease.[2] In addition to the acute presentation, a portion of pediatric patients also develop a newly described syndrome called multisystem inflammatory syndrome in children (MIS-C), particularly destructive inflammation that affects all organs including the heart.[3] The severity of the pandemic combined with its health and economic toll has made finding treatment and vaccines a pressing issue. This has prompted an unprecedented push for repurposed treatments such as dexamethasone in addition to novel medications and vaccines including remdesivir, convalescent plasma, and monoclonal antibodies.

Three monoclonal antibody treatments were developed for mild- to-moderate COVID-19 infection. Bamlanivimab, also known as LY-CoV555, is a monoclonal antibody developed with a partnership between AbCellera Biologics and Eli Lilly. It was found to be effective primarily in an outpatient setting whereby having received bamlanivimab reduced hospital admission or emergency room visits, while also decreasing the viral load faster than in patients who have not received treatment.[4] Bamlanivimab was later combined with etesevimab as a treatment, with additional randomized controlled trials showing this combination resulted in significant reduction in viral load compared with placebo.[5] Another monoclonal antibody developed for treatment of mild-to-moderate symptoms of COVID-19 infection was casirivimab/imdevimab, also known as REGEN-COV. Produced by Regeneron pharmaceuticals, it is an intravenous infusion of 2 monoclonal antibodies that are directed against the SARS-CoV-2 spike protein.[6] The promising results from early trials of monoclonal antibody treatments prompted the Food and Drug Administration (FDA) to issue an emergency use authorization (EUA) for bamlanivimab ± etesevimab and casirivimab/imdevimab for mild-to-moderate COVID-19 patients who are at risk for severe disease and/or hospitalization but not yet hospitalized.[7,8]

Despite the FDAs EUA regarding monoclonal antibody eligibility criteria, the use and administration in the pediatric population remains limited. This is likely due to a variety of factors including novelty of therapy, logistical limitations and lack of data in the pediatric population. In January 2021, a group of pediatric clinicians including infectious disease, critical care, pharmacy and hematology issued an expert opinion regarding its use in pediatric patients.[9] Based on the lack of pediatric data, their consensus did not recommend routine use of monoclonal antibodies in the pediatric population, even if patients meet the FDA criteria for high-risk of progression to hospitalization or severe disease.[9] This has led to individual centers taking a variety of approaches and also perpetuates the data gaps in the literature regarding tolerability and short-term outcomes of those who received treatment. As such this paper seeks to bridge this gap in monoclonal antibody therapy in pediatric patients and provide data for future use and studies.

METHODS

Patients who received monoclonal antibody infusions for the treatment of mild-moderate COVID-19 at Children’s National Hospital located in Washington DC, from December 2020 to April 2021 were included in the review. The criteria for infusion at this institution were patients age 12 years old and older. Patients were referred to the Emergency Department/Infusion center for treatment if advised by their primary care provider and after eligibility and appropriateness of treatment were confirmed by an infectious disease provider. Pertinent patient information and demographics, type of infusion, adverse reactions and subsequent admissions from December 2020 to April 2021 were extracted from their charts. Monoclonal antibody infusion doses and rates were as follows: bamlanivimab 700 mg and casirivimab/imdevimab 2400 mg both infused over 60 minutes, and bamlanivimab 700 mg + etesevimab 1400 mg infused over 30 minutes. All patients were monitored for infusion-related reactions during and at least 60 minutes after infusion.

RESULTS

A total of 17 pediatric patients received monoclonal antibody treatment for SARS-CoV-2. All infusions were administered in the emergency department. The youngest patient was 12 and oldest 20 years old, with the most common comorbidities in this patient population were diabetes and obesity (Table 1). Twelve patients received bamlanivimab, 3 patients received the combination casirivimab/imdevimab and 2 patients received bamlanivimab + etesevimab (Table 2). There were no significant adverse effects or reactions that required cessation of infusion such as anaphylaxis, hypotension or dyspnea (Table 2). Two patients (12%) developed a potential infusion reaction, one having fever and the other a headache. However, these symptoms are difficult to differentiate between medication reaction and COVID-19 symptoms as both are a part of the known symptomology (Table 2). Supportive measures were taken with medications leading to symptom resolution and continuance of transfusion. One of 17 patients (6%), who received bamlanivimab, was readmitted to the hospital 6 days after transfusion and diagnosed with severe COVID-19 pneumonia requiring treatment with remdesivir and dexamethasone. No other patient was readmitted for reasons related to COVID-19 or MIS-C within 30 days after receiving treatment.

TABLE 1.

Patient Demographics and COVID-19 Symptomology

Subjects	Age	Sex	Race	Comorbid Conditions	COVID Symptoms
Patient 1	20	M	Caucasian	T1DM	Headache, cough, congestion
Patient 2	15	F	Black	T1DM	Anosmia, ageusia, fatigue, pharyngitis, rhinorrhea
Patient 3	13	F	Other	chronic neutropenia, asthma, obesity	Cough, myalgia, headache, fatigue, fever
Patient 4	20	F	Black	Addison’s disease, asthma, GI dysfunction, migraine, obesity, POTS, visceral hyperalgesia	Cough, fever, headache
Patient 5	15	F	Caucasian	Celiac, T1DM	Headache, pharyngitis, myalgia
Patient 6	12	F	Hispanic	T1DM	Fever, pharyngitis, myalgia
Patient 7	13	M	Black	Stickler syndrome, asthma, hypertension, obesity	Cough, dyspnea
Patient 8	17	M	Caucasian	T1DM	Anosmia, ageusia, headache, fatigue, myalgia
Patient 9	17	M	Black	Asthma, hypertension, obesity	Anosmia, pharyngitis, chest pain, headache, fatigue, myalgia
Patient 10	17	M	Black	Obesity, T2DM	Abdominal pain, fatigue
Patient 11	17	F	Black	Trisomy 21, ASD, VSD, pHTN, OSA, asthma, obesity	Cough
Patient 12	17	F	Black	Asthma, obesity	Pharyngitis
Patient 13	17	F	Black	Obesity, T2DM	None—symptoms not recorded
Patient 14	15	M	Black	Obesity, T2DM	None—symptoms not recorded
Patient 15	19	M	Black	Asthma, obesity	Headache, cough, diarrhea, dyspnea,
Patient 16	13	M	Black	Asthma, obesity	Chest pain, congestion, cough, dyspnea, fever, headaches, myalgias, pharyngitis
Patient 17	14	M	Black	Corpus callosum agenesis, obesity	Fever, myalgias

F indicates female; M, male; T1DM, type 1 diabetes mellitus; T2DM, type 2 diabetes mellitus.

TABLE 2.

Monoclonal Antibody Treatment Information

	Days of Symptoms	Days From Positive Test to Treatment	Medication Received	Infusion Reactions	30-d Admission
Patient 1	3	3	Bamlanivimab	None	N
Patient 2	Not reported	0	Bamlanivimab	None	N
Patient 3	2	0	Bamlanivimab	Headache	N
Patient 4	3	0	Bamlanivimab	Fever	N
Patient 5	3	0	Bamlanivimab	None	N
Patient 6	2	0	Bamlanivimab	None	N
Patient 7	Not reported	1	Bamlanivimab	None	N
Patient 8	2	1	Bamlanivimab	None	N
Patient 9	2	2	Bamlanivimab	None	N
Patient 10	5	0	Bamlanivimab	None	N
Patient 11	1	0	Bamlanivimab	None	Y
Patient 12	1	1	Bamlanivimab	None	N
Patient 13	0	0	Casirivimab/imdevimab	None	N
Patient 14	0	0	Casirivimab/imdevimab	None	N
Patient 15	7	2	Casirivimab/imdevimab	None	N
Patient 16	3	1	Bamlanivimab/etesevimab	None	N
Patient 17	1	1	Bamlanivimab/etesevimab	None	N

N, No; Y, Yes.

DISCUSSION

Monoclonal antibodies may be an important tool in the struggle against COVID-19 in pediatrics as timing of vaccine eligibility, vaccine uptake in the younger age groups and vaccine responses in immunocompromised population remains unknown. Despite EUA approval on November 2020, our literature review found no documentation of monoclonal antibody treatment for mild-to-moderate SARS-CoV-2 infection in pediatric patients. The data from Children’s National Hospital at the height of the pandemic in March through April 2020 calculated a hospitalization rate of approximately 25% of all positive tests in our pediatric community with 80% of the patients hospitalized for COVID-19 pneumonia or MIS-C requiring critical care.[2] Despite the lower morbidity and mortality compared with adult patients, this still involves significant healthcare resources and may entail unknown long-term consequences. Our limited number of 17 patients shows that monoclonal antibody treatment for mild-to-moderate SARS-CoV-2 infection was well tolerated and may be effective in halting progression to severe disease and prevention of hospitalization. Only one patient (6%) in our cohort of high-risk patients required admission. This particular patient had significant congenital cardiac disease and multiple comorbidities such as pulmonary hypertension and obesity and ultimately led to prolonged hospitalization with a significant portion requiring intensive care. However, these results should be interpreted with caution as there are significant limitations in this case series. Sample size is small and there are several potential confounders including variation in viral strain, utilization of different monoclonal antibodies given changing EUA’s, and possibility that patients were admitted to a different institution than where they received the infusion. Long-term follow up data are also needed, particularly in evaluation for subsequent impact on development of MIS-C. Despite these limitations, these cases do provide information and data in the pediatric literature and will support pediatric specific trials.

Since pediatric clinical trials on novel medications and interventions are lacking, formal guidelines and recommendations are unable to provide any guidance citing the lack of data. The lack of formal guidance generates little enthusiasm for providers to justify use of these medications and treatment which in turn perpetuates the lack of data. This creates a continuous cycle of sparse data and lack of guidelines for frontline providers. While our data is limited, this article provides preliminary information for future studies of antibody treatment for a disease that carries a significant morbidity in the pediatric population.