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Visual Abstract. Azithromycin (AZM) Treatment in Children With Respiratory Syncytial Virus (RSV)–Induced Respiratory Failure
Azithromycin (AZM) Treatment in Children With Respiratory Syncytial Virus (RSV)–Induced Respiratory Failure
Figure 1.  Flow Diagram of Trial
Flow Diagram of Trial

AZM indicates azithromycin.

Figure 2.  Change in MMP-9 and TIMP-1 Levels
Change in MMP-9 and TIMP-1 Levels

Each panel shows the estimate of means with 99.8% CIs, whereby treatment effect is defined as the change (ie, posttreatment minus pretreatment) at each day for a given treatment. Therefore, a nonzero mean difference indicates a treatment effect for the given day and treatment (placebo vs standard-dose azithromycin [AZM] vs high-dose AZM) for the cytokines measured in the nasal and endotracheal secretions. MMP-9 indicates matrix metalloproteinase–9; and TIMP-1, tissue inhibitor of metalloproteinase–1.

Table 1.  Pharmacokinetic Parameters for Standard- and High-Dose AZM Using Urea-Corrected Data
Pharmacokinetic Parameters for Standard- and High-Dose AZM Using Urea-Corrected Data
Table 2.  Clinical Outcome Measures
Clinical Outcome Measures
Table 3.  Mean Ratio Estimates for Clinical Outcomes
Mean Ratio Estimates for Clinical Outcomes
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    1 Comment for this article
    Chronic Reactive AIrway Disease
    Paul Nelson, M.S., M.D. | Family Health Care, P.C. retired
    I am curious about the potential long-term outcome of whether or not the RSV afflicted child needed the regular use of bronchodilator strategies at 24 months following discharge from the child's RSV hospitalization. This would be especially important if the index RSV hospitalization was the child's initial episode of RSV bronchiolitis.
    CONFLICT OF INTEREST: None Reported
    Original Investigation
    Critical Care Medicine
    April 23, 2020

    Azithromycin Treatment vs Placebo in Children With Respiratory Syncytial Virus–Induced Respiratory Failure: A Phase 2 Randomized Clinical Trial

    Author Affiliations
    • 1Department of Pediatrics, University of Alabama at Birmingham
    • 2McWhorter School of Pharmacy, Samford University, Birmingham, Alabama
    JAMA Netw Open. 2020;3(4):e203482. doi:10.1001/jamanetworkopen.2020.3482
    Key Points español 中文 (chinese)

    Question  Is azithromycin (AZM) safe, and does it reduce nasal and endotracheal matrix metalloproteinase 9 (MMP-9) levels in children with respiratory syncytial virus–induced respiratory failure?

    Findings  In this randomized phase 2 clinical trial that included 48 children admitted to the pediatric intensive care unit with respiratory syncytial virus lung disease who required positive pressure ventilation, AZM was safe. No difference in nasal MMP-9 levels was observed between treatment group, but in those who required mechanical ventilation and received a high dose of AZM, endotracheal active and total MMP-9 levels were lower on day 3 of treatment.

    Meaning  In this study, high doses of AZM were safe, reduced endotracheal MMP-9 levels in patients receiving mechanical ventilation, and potentially improved outcomes in critically ill children with respiratory syncytial virus infections.

    Abstract

    Importance  Despite a high disease burden, there is no effective treatment for respiratory syncytial virus (RSV) infection.

    Objectives  To determine whether administration of azithromycin (AZM) to children with RSV-induced respiratory failure is safe and to define the effect of AZM therapy on nasal matrix metalloproteinase 9 (MMP-9) levels.

    Design, Setting, and Participants  This randomized, double-blind, placebo-controlled phase 2 trial was conducted at a single tertiary pediatric intensive care unit from February 2016 to February 2019. The study included children with RSV infection who were admitted to the pediatric intensive care unit and required respiratory support via positive pressure ventilation (invasive and noninvasive). A total of 147 children were screened; 90 were excluded for not meeting inclusion criteria, having an absent legal guardian, lacking pharmacy support, or having a language barrier and 9 declined participation, resulting in 48 patients enrolled in the study.

    Intervention  Receipt of standard dose AZM (10 mg/kg/d), high-dose AZM (20 mg/kg/d), or a matching placebo of normal saline intravenously for 3 days.

    Main Outcomes and Measures  Nasal and endotracheal samples were collected at baseline as well as at 24 hours and 48 hours after start of treatment. The secondary outcome was to determine treatment effect on clinical outcome measures, including days of positive pressure ventilation and length of hospital stay.

    Results  A total of 48 patients were enrolled in the trial, with a median (range) age at randomization of 12 (1 to 125) months; 36 participants (75.0%) were younger than 2 years. Overall, 26 participants (54.2%) were boys, and 29 (60.4%) had a comorbidity. A total of 16 patients were randomized into each trial group (ie, placebo, standard-dose AZM, and high-dose AZM). Baseline demographic characteristics were comparable among the 3 groups. Both doses of AZM were safe, with no adverse events observed. No difference in nasal MMP-9 levels were observed between treatment groups. Among those who required mechanical ventilation and received high-dose AZM, endotracheal active and total MMP-9 levels were lower on day 3. Compared with baseline, active and total MMP-9 levels in endotracheal aspirates were 1.0 log lower in the high-dose AZM group (active MMP-9: 99.8% CI, −1.28 to −0.64; P < .001; total MMP-9: 99.8% CI, −1.37 to −0.57; P < .001). Patients who received high-dose AZM had fewer median (interquartile range) hospital days compared with those receiving the placebo (8 [6-14] days vs 11 [8-20] days; mean ratio estimate, 0.57; 95% CI, 0.38-0.87; P = .01).

    Conclusions and Relevance  In this phase 2 randomized clinical trial, both doses of AZM were safe. While nasal MMP-9 levels were unchanged among treatment groups, endotracheal MMP-9 levels were lower among those who received high-dose AZM. The positive secondary clinical outcome, while exploratory, provides insight for end points in a multicenter randomized trial.

    Trial Registration  ClinicalTrials.gov Identifier: NCT02707523

    Introduction

    Respiratory syncytial virus (RSV) infection has a substantial global disease burden.1-4 Matrix metalloproteinases (MMPs) are proteases implicated in the pathogenesis of both acute and chronic lung disease.5-11 In 2015, we reported12 that early elevation of endotracheal MMP-9 levels was positively associated with RSV disease severity and that MMP-9 inhibition decreased RSV replication in a murine model, suggesting that MMP-9 might be a potential marker of disease severity and a therapeutic target in RSV disease.

    Macrolides are a class of antibiotics that are known to penetrate cells, making them active against intracellular pathogens; azithromycin (AZM) is reported to have a long intracellular half-life.13 In addition, AZM is an immune modulator that has been reported to provide clinical benefit in inflammatory airway diseases.14,15 Therefore, we performed a randomized, placebo-controlled phase 2 trial to test the hypothesis that AZM therapy during RSV-induced respiratory failure was safe and would reduce nasal and lung MMP-9 levels as well as to explore preliminary effects on the disease course for planning a subsequent definitive trial.

    Methods
    Participants

    Eligible participants included all children admitted to the pediatric intensive care unit (PICU) at Children’s of Alabama (Birmingham) with a diagnosis of RSV infection and requiring positive pressure ventilation, invasive or noninvasive, including bilevel positive airway pressure (BiPAP) or high-flow nasal cannula (HFNC) oxygen (ie, >1 L/kg/min of flow, with ≥5 L/min flow for children weighing <5 kg). When the trial began in February 2016, it only included patients with RSV with respiratory failure requiring mechanical ventilation, but in December 2016, it was expanded to include patients with respiratory failure supported on noninvasive positive pressure ventilation. This was to reflect the overall change in the PICU’s practice whereby more patients had a trial of management using BiPAP or HFNC before mechanical ventilation. Exclusion criteria included use of AZM within 7 days of PICU admission, any contraindication to AZM use, cardiac arrhythmias, electrocardiogram with QT interval corrected for heart rate of at least 450 milliseconds, history of pyloric stenosis, and receipt of immunosuppressant.

    During hospitalization, all patients were treated according to the American Academy of Pediatrics guidelines for the management of bronchiolitis,16 primarily supportive care. The study protocol was approved by the University of Alabama at Birmingham institutional review board, and a data and safety monitoring board serially evaluated the study. An Investigational New Drug approval was obtained from the US Food and Drug Administration for the use of AZM in this trial (Investigational New Drug number, 127632). Participants’ legal guardians provided written informed consent before randomization into the trial. The Consolidated Standards of Reporting Trials (CONSORT) guideline was used for the reporting of this trial.17 The trial protocol is available in Supplement 1.

    Study Design and Treatment

    The study was a double-masked, placebo-controlled parallel group trial with 3 treatment groups. All participants, their families, health care professionals, and study staff were masked to study medication allocation, with the exception of the biostatistician and the pharmacist. Participants were randomized according to a permuted-block design to receive either placebo (saline) or AZM (Fresenius Kabi) at 10 mg/kg/d (ie, standard dose) or 20 mg/kg/d (ie, high dose) intravenously every 24 hours for 3 days. The randomization schedule was created by the study biostatistician and provided to the study pharmacist for implementation.

    Nasal and endotracheal samples (if intubated) were collected from all participants before treatment as well as at 24 hours and at 48 hours after treatment started. For patients who were intubated, only nasal samples were collected once extubated. No long-term follow-up was performed.

    The study spanned 3.5 RSV seasons, from February 2016 to February 2019. Owing to the initial age restriction placed by the Food and Drug Administration, the first 9 participants enrolled were older than 6 months. Once this number was reached and no safety concerns were evident as determined by the data and safety monitoring board, infants younger than 6 months were eligible for enrollment in the study.

    The primary outcomes of this trial were as follows: (1) to ascertain the safety of AZM and its pharmacokinetics and (2) to determine whether treatment with AZM resulted in decreased nasal MMP-9 levels. When the study protocol was expanded to include patients who were not ventilated, the primary outcome also changed from endotracheal MMP-9 levels to nasal MMP-9 levels. The secondary outcomes were to determine the in vivo efficacy of AZM administration on improving clinical outcome measures, specifically duration of ventilatory support and oxygenation as well as PICU and hospital lengths of stay.

    Nasal and Endotracheal Aspirate Collection and Processing

    Nasal samples were collected using a nasal swab inserted through the nares. The swab was then immediately placed in a vial containing 3 mL of viral transport media (Quidel). Endotracheal aspirates were collected via endotracheal tube suctioning using an 8 French suction cannula (CareFusion) and centrifuged at 500g for 10 minutes to separate supernatant from cells and mucus (pellet). All samples were kept at 4 °C for further analysis.

    Assay of AZM and Urea Levels and Pharmacokinetic Analysis

    We measured AZM and urea levels in endotracheal and plasma samples using liquid chromatography–tandem mass spectrometric assays. Dilution estimations of endotracheal samples were calculated using the urea dilution method.18 Peak plasma levels (Cmax) and time to Cmax (Tmax) of AZM were determined by visual evaluation of the concentration vs time profile. The area under the curve (AUC) values were calculated using the trapezoidal rule. The half-life (t1/2) of AZM was calculated as natural log of 2 / ke, in which ke was the terminal elimination rate constant estimated by linear regression analysis of the terminal portion of the concentration-time profile. Penetration ratios for AZM in samples from the endotracheal compartment were calculated as the AUC of the endotracheal compartment divided by the AUC of plasma.

    Biologic Outcome Measurement

    Measurement of active MMP-9, total MMP-9, and tissue inhibitor of metalloproteinase 1 (TIMP-1) were done using established fluorometric assays (F9M00 and DTM100, respectively; R&D Systems). Interleukin 1 (IL-1), IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-13, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ) were analyzed via electrochemiluminescence using the Meso Scale Discovery V-PLEX Cytokine Panel 1 Human Kit (K15049D-1; Meso Scale Diagnostics). We measured RSV loads by reverse-transcription quantitative polymerase chain reaction using known concentrations of RSV to derive a standard curve.19 Standards and negative controls were included and tested with each polymerase chain reaction assay. We reported RSV quantification as log10 copies per mL.

    Clinical Data Assessment

    The clinical data collected included duration of respiratory support (focusing on days of mechanical ventilation, noninvasive positive pressure ventilation via BiPAP or HFNC, and total duration of supplemental oxygen), PICU stay, and hospital stay. Comorbidities and the presence of multiorgan failure20 were also identified.

    Sample Size Determination and Statistical Analysis

    This study was designed to have a total sample of 48 participants divided in 3 groups, with 16 per group, to detect a 25% and 37.5% decrease in lung MMP-9 activity in the standard-dose and high-dose groups, respectively, relative to placebo, with 80% power using analysis of variance. The assumptions were based on MMP-9 levels found in endotracheal aspirate of children with RSV-induced respiratory failure.13

    Statistical Analysis

    Means, standard deviations, medians, quartiles, and ranges (minimum, maximum) were used to describe continuous variables, and counts and percentages were used for categorical variables. To compare baseline characteristics among the treatment groups, we used the Kruskal-Wallis test for age, height, and weight due to evidence of nonnormality of the distribution of the values. We used either χ2 or Fisher exact test for categorical variables depending on expected cell counts.

    We analyzed inflammatory markers by first performing log10 transformation to address the skewedness of the distribution and extreme outliers. We then calculated the difference at each point relative to baseline to obtain the change (ie, pretreatment and posttreatment) outcome and fitted a generalized linear mixed model with random intercepts and assumed unequal variances across treatment groups with change from baseline as the outcome. The Bonferroni approach was used to adjust for multiple testing (with a 2-tailed P  <  .002 as the threshold for statistical significance) and simultaneous confidence intervals (99.8% confidence level).

    For clinical outcomes (measured in number of days), we used a generalized linear model assuming a negative binomial distribution using log link function to address possible overdispersion due to some extreme observations. For this set of analyses, a 2-tailed P < .05 was set as the level of significance, with 95% CIs. All analyses were done using SAS version 9.4 (SAS Institute).

    Results
    Enrollment and Baseline Characteristics

    A total of 147 patients were screened, and 48 patients (32.7%) were randomized (Figure 1). All enrolled patients completed the study. The median (range) age of patients at randomization was 12 (1-125) months, with 36 (75.0%) younger than 2 years. Overall, 26 participants (54.2%) were boys, and 29 (60.4%) had a comorbidity. Baseline demographic characteristics were comparable among the 3 groups (eTable in Supplement 2). At the time of randomization, 34 patients (70.8%) required mechanical ventilation, 2 (4.2%) received BiPAP support, and the remaining 12 patients (25.0%) received HFNC. Once extubated, 4 (11.8%) received BiPAP, and 22 (64.8%) were transitioned to HFNC. A total of 5 of 34 patients (14.7%) were extubated before day 3. No patients who initially received BiPAP or HFNC at randomization required intubation.

    Pharmacokinetics of AZM

    The pharmacokinetic parameters for AZM are listed in Table 1. A linear dose-dependent response was observed for the mean (SD) AUC values of AZM in plasma between the standard-dose and high-dose groups (14.8 [5.5] μg x h/mL vs 25.3 [13.2] μg x h/mL), while a nonlinear dose response was noted for the endotracheal samples between AZM groups (892.4 [383.7] μg x h/mL vs 807.3 [331.0] μg x h/mL). We observed that mean (SD) Cmax values were higher in the high-dose group for plasma than in the standard-dose group (0.34 [0.06] μg/mL vs 0.22 [0.09] μg/mL; P < .001) and comparable for corresponding endotracheal samples (8.7 [1.1] μg/mL vs 11.0 [1.5] μg/mL; P = .008). The times to Cmax were the same between dose groups for plasma and for endotracheal samples in the standard-dose group, but it was prolonged for the endotracheal samples in the high-dose group. An inverse dose-dependent penetration ratio (2:1) was observed in the endotracheal samples between the standard-dose and high-dose groups, respectively (48 h for the standard-dose group; 96 h for the high-dose group). This observation was due to comparable endotracheal AUC values between dose groups, while the plasma AUC values exhibited a linear dose dependent relationship. The comparable endotracheal AUC values were likely due to extensive distribution of AZM in the respiratory tract, resulting in drug saturation.

    Safety Profile and Adverse Events

    All participants were monitored daily for adverse events using National Institutes of Health event recording21 from the time of study enrollment until discharge from the PICU. No gastrointestinal adverse events (ie, diarrhea, vomiting, or abdominal distention), feeding intolerance, thrush, intravenous site reactions, or rash were documented in any of the study participants. We measured QT interval corrected for heart rate daily during the treatment phase, and all were within normal range. There were no abnormal vital signs or arrhythmias noted during or within 4 hours of drug administration. Finally, no abnormal laboratory values attributable to the study drug were documented.

    Profiles of MMP-9 and Cytokine Levels at Baseline and After Treatment

    In nasal secretions, compared with baseline values, no difference was noted in active and total MMP-9 levels or the level of its natural inhibitor, TIMP-1, at hour 48 or hour 72 after treatment started in all 3 groups (Figure 2A, Figure 2B, and Figure 2C). At 48 hours after treatment began, the endotracheal aspirates showed that active MMP-9 was 0.4 log lower (99.8% CI, −1.07 to 0.28; P = .051) in the placebo group, 0.3 log lower (99.8% CI, −1.42 to 0.85; P = .39) in the standard-dose AZM group, and 0.5 log lower (99.8% CI, −1.04 to 0.14; P = .01) in the high-dose AZM group compared with baseline values (Figure 2D). At 72 hours after treatment began, active MMP-9 levels in endotracheal aspirates were 0.4 log lower (99.8% CI, −1.45 to 0.70; P = .23) in the placebo group, 0.4 log lower (99.8% CI, −1.86 to 1.05; P = .34) in the standard-dose AZM group, and 1.0 log lower (99.8% CI, −1.28 to −0.64; P < .001) in the high-dose AZM group compared with baseline values (Figure 2D).

    At 48 hours after treatment began, total MMP-9 levels in endotracheal aspirates were 0.4 log lower (99.8% CI, −1.01 to 0.29; P = .06) in the placebo group, 0.5 log lower (99.8% CI, −1.98 to 0.89; P = .20) in the standard-dose AZM group, and 0.5 log lower (99.8% CI, −0.92 to 0.02; P = .003) in the high-dose AZM group compared with baseline values (Figure 2E). At 72 hours after treatment began, total MMP-9 in endotracheal aspirates was 0.4 log lower (99.8% CI, −1.26 to 0.52; P = .16) in the placebo group, 0.5 log lower (99.8% CI, −1.80 to 0.86; P = .23) in the standard-dose AZM group, and nearly 0.97 log lower (99.8% CI, −1.37 to −0.57; P < .001) in the high-dose AZM group compared with baseline values (Figure 2E). No significant difference was observed in endotracheal TIMP-1 values before and after treatment among the placebo and AZM groups (Figure 2F). Endotracheal TNF-α was 1.2 log lower (TNF-α: 99.8% CI, −1.92 to −0.47; P < .001) and IL-1 was 1.1 log lower (99.8% CI, −1.77 to −0.35; P < .001) in the high-dose AZM group 48 hours after treatment began compared with baseline (eFigures 1A and 1B in Supplement 2). Likewise, endotracheal IL-10 was 0.84 log lower (99.8% CI, −1.48 to −0.21; P < .001) at hour 48 and 1.2 logs lower (99.8% CI, −1.74 to −0.58; P < .001) 72 hours after treatment began compared with baseline in the high-dose AZM group (eFigure 1C in Supplement 2). No significant differences were observed for nasal TNF-α, IL-1, and IL-10 or for nasal and endotracheal INF-γ, IL-2, IL-6, IL-8, IL-12, and IL-13 in the placebo and both AZM groups (data not shown). Absolute concentrations of nasal active MMP-9, total MMP-9, and TIMP-1 as well as endotracheal active MMP-9, total MMP-9, TIMP-1, TNF-α, IL-1, and IL-10 are shown for pretreatment, 48 hours after treatment began, and 72 hours after treatment began in eFigure 2 in Supplement 2.

    Viral Load

    At baseline, the mean (SD) RSV load measured in the endotracheal aspirate was no different among the 3 groups at 2.6 (1.0) log10 plaque-forming unit (PFU)/mL in the placebo group, 2.5 (1.5) log10 PFU/mL in the standard-dose AZM group, and 2.1 (0.8) log10 PFU/mL in the high-dose AZM group. On day 2 of treatment, the mean (SD) RSV load decreased to 1.2 (0.5) log10 PFU/mL in the placebo group, 1.2 (0.5) log10 PFU/mL in the standard-dose AZM group, and 0.36 (0.2) log10 PFU/mL in the high-dose AZM group. On day 3 of treatment, the mean (SD) RSV load was lowest in the high-dose AZM group, at 0.1 (0.1) log10 PFU/mL compared with 1.1 (0.4) log10 PFU/mL in the standard-dose AZM group, and 0.4 (0.3) log10 PFU/mL in the placebo group, but this did not reach statistical significance (P = .49) (eFigure 3A and 3B in Supplement 2). Nasal RSV titer correlated positively with INF-γ on day 3 (R2 = 0.47; P = .002). For children who were intubated, endotracheal RSV titer positively correlated with INF-γ at randomization (R2 = 0.44; P = .01) and, for the treatment group, at 24 hours after treatment began (R2 = 0.64; P = .004) and 48 hours after treatment began (R2 = 0.52; P = .05). No correlation was seen between viral titer and all other measured cytokines in both the nasal and endotracheal aspirate (data not shown).

    Clinical Outcomes

    Table 2 summarizes the clinical outcome findings (ie, days of ventilator support, mechanical ventilation, BiPAP, HFNC, oxygenation, durations of PICU and hospital stay, and presence of multiorgan failure) for the entire study cohort as well as for the placebo and AZM treatment groups separately. Table 3 summarizes the overall treatment effect on clinical variables and by group comparisons. Median (interquartile range) length of hospital stay was lower in the high-dose group than the placebo group (8 [6-14] days vs 11 [8-20] days; mean ratio estimate, 0.57; 95 CI, 0.38-0.87; P = .01).

    Discussion

    To the best of our knowledge, this is the first randomized placebo-controlled trial of AZM at multiple doses in children with severe RSV infection and lung disease who required PICU management and positive pressure ventilation. We demonstrated preliminary efficacy of AZM, specifically at a higher dose, in the reduction of biomarkers modulated by RSV infection and in reducing duration of hospitalization in a critically ill cohort of hospitalized children.

    Disease severity in RSV infection has been linked with excessive release of cytokines.22-27 Previous studies have shown that AZM attenuates cytokine production, which may reduce the disease severity seen in respiratory viral infections.28 Furthermore, preclinical studies have shown the antiviral effects of AZM.29,30 Given these properties, AZM has been studied for its potential use as targeted therapy for a wide spectrum of viral respiratory infections, including RSV. However, clinical trials of AZM and other macrolides in RSV infection have yielded conflicting results. In the first trial by Tahan et al,31 the investigators reported that treatment with clarithromycin reduced hospital length of stay and supplemental oxygen need compared with placebo. In contrast, subsequent trials using enteral AZM failed to demonstrate any clinical benefit.32-35 In previously reported negative trials, the study design, including patient population (non-ICU patients), macrolide dosing (1-3 doses during 1-14 days), and route of AZM administration (enteral) likely contributed to the difference seen in the findings of this trial. In a 2015 trial,15 treatment of RSV bronchiolitis with AZM reduced overall respiratory morbidity and, in another,36 decreased the progression to severe lower respiratory tract infection in preschool children.

    Given the uncertainty regarding optimal dosing to achieve anti-inflammatory activity, we included a high-dose AZM group to maximize the likelihood of achieving adequate and sustained AZM levels. Others have suggested increased effectiveness of high-dose AZM in Ureaplasma urealyticum clearance in preterm infants.37-39 In this study, we demonstrated that high doses of AZM were safe. Although the nasal levels of MMP-9, TIMP-1, and the other RSV-related cytokines were similar among the placebo and AZM treatment groups, endotracheal active and total MMP-9, TNF-α, IL-1, and IL-10 were lower after treatment in the high-dose AZM group compared with baseline values. We also observed that RSV titer in the nasal and lung compartment decreased among all patients, and although those treated with high doses of AZM had the lowest viral burden at the end of the third dose, this finding was not significant. Although exploratory in nature, we also found that the median number of hospital days was approximately 3 days less in the high-dose group compared with the placebo group.

    Limitations

    This study has limitations, including its small sample size. Although we observed decreased numbers of ventilator support and oxygen days as well as shorter duration of PICU stay in the high-dose AZM group, future studies will need to be powered to detect changes in these clinical outcome measures based on the findings of this trial. Also, it is possible that practice variation might have contributed to the clinical differences seen between the placebo vs treatment group. However, the masking of the study ensured no biases toward any particular group, and practice variation was also limited given that our unit in general follows the same respiratory weaning protocol. Furthermore, sensorineural hearing loss is a possible, although rare, adverse effect of AZM use and was not tested in our patients.

    Conclusions

    We found that both doses of AZM were safe. No difference was observed in nasal MMP-9 levels across all groups. Patients who received high-dose AZM had lower endotracheal MMP-9 levels and had fewer hospitalization days. This trial provides the necessary foundation to plan a larger, multicenter randomized clinical trial that will be critical in determining the clinical effectiveness of high-dose AZM among children with severe RSV lung disease.

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    Article Information

    Accepted for Publication: February 21, 2020.

    Published: April 23, 2020. doi:10.1001/jamanetworkopen.2020.3482

    Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2020 Kong M et al. JAMA Network Open.

    Corresponding Author: Michele Kong, MD, Department of Pediatrics, University of Alabama at Birmingham, 1600 Fifth Ave S, PPS 102, Birmingham, AL 35233 (mkong@peds.uab.edu).

    Author Contributions: Dr Kong had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Drs Ambalavanan and Whitley contributed equally to this work.

    Concept and design: Kong, Aban, Ambalavanan, Whitley.

    Acquisition, analysis, or interpretation of data: All authors.

    Drafting of the manuscript: Kong, Sewell, Gorman, Aban, Ambalavanan.

    Critical revision of the manuscript for important intellectual content: Kong, Zhang, Gorman, Kuo, Aban, Ambalavanan, Whitley.

    Statistical analysis: Kong, Kuo, Aban.

    Obtained funding: Kong.

    Administrative, technical, or material support: Kong, Zhang, Sewell, Gorman, Ambalavanan, Whitley.

    Supervision: Whitley.

    Conflict of Interest Disclosures: Dr Aban reported receiving grants from the National Institutes of Health, the Myasthenia Gravis Foundation of America, Alexion, argenx, Catalyst Pharmaceutical, RA Pharmaceutical, and the Transverse Myelitis Association outside the submitted work. Dr Amabalavanan reported receiving grants from the National Institutes of Health during the conduct of the study. Dr Whitley reported receiving grants from the National Institutes of Health during the conduct of the study and receiving personal fees from Gilead Sciences outside the submitted work. No other disclosures were reported.

    Funding/Support: This work was funded by grant UL1TR003096 from the University of Alabama at Birmingham Center for Clinical and Translational Science.

    Role of the Funder/Sponsor: The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

    Data Sharing Statement: See Supplement 3.

    Additional Contributions: We thank the members of the data and safety monitoring board, Nancy Tofil, MD (chair; University of Alabama at Birmingham), Kim Benner, PharmD (McWhorter School of Pharmacy), Stephen Robert, MD (Cedars Sinai), Charity Morgan, PhD (University of Alabama at Birmingham), and David Kimberlin, MD (University of Alabama at Birmingham), for their time and oversight. We thank the Department of Pediatrics Research Office and the University of Alabama at Birmingham Center for Clinical and Translational Science for their ongoing support of this work. Finally, we thank the members of the scientific oversight committee, David Redden, PhD (University of Alabama at Birmingham), and Steven Rowe, MD (University of Alabama at Birmingham), for their insights. None of these individuals were compensated for their time.

    Additional Information: Because of a data entry oversight in ClinicalTrials.gov, the primary outcomes were originally listed only as azithromycin pharmacokinetics, oxygen support, and multiorgan system failure scores. No secondary outcomes were listed. We provided regulatory documentation, including institutional review board and Investigational New Drug submissions and approvals that confirmed studies performed prospectively on these children, with the primary and secondary outcomes as stated in the manuscript.

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