Designing of a new transdermal antibiotic delivery polymeric membrane modified by functionalized SBA-15 mesoporous filler.

A new drug delivery system using an asymmetric polyethersulfone (PES) membrane modified by SBA-15 and glutamine-modified SBA-15 (SBA-Q) was prepared in this study by the aim of azithromycin delivery enhancement in both in vitro and ex vivo experiments. The research focused on optimizing membrane performance by adjusting critical parameters including drug concentration, membrane thickness, modifier percentage, polymer percentage, and pore maker percentage. To characterize the fabricated membranes, various techniques were employed, including scanning electron microscopy, water contact angle, and tensile strength assessments. Following optimization, membrane composition of 17% PES, 2% polyvinylpyrrolidone, 1% SBA-15, and 0.5% SBA-Q emerged as the most effective. The optimized membranes demonstrated a substantial increase in drug release (906 mg/L) compared to the unmodified membrane (440 mg/L). The unique membrane structure, with a dense top layer facilitating sustained drug release and a porous sub-layer acting as a drug reservoir, contributed to this improvement. Biocompatibility assessments, antibacterial activity analysis, blood compatibility tests, and post-diffusion tissue integrity evaluations confirmed the promising biocompatibility of the optimized membranes. Moreover, long-term performance evaluations involving ten repeated usages underscored the reusability of the optimized membrane, highlighting its potential for sustained and reliable drug delivery applications.

Population Pharmacokinetics and Individualized Medication of Azithromycin for Injection in Children Under 6 Years Old.

Pharmacokinetic data for injectable azithromycin in children remain limited. This study aims to develop and validate a population pharmacokinetic model of azithromycin for injection in children under 6 years old and optimize its dosage regimen in this population. We prospectively enrolled patients under 6 years old who received azithromycin for injection at Beijing Friendship Hospital, Capital Medical University. Demographic information, clinical characteristics, and venous blood samples were collected in accordance with the research protocol. Azithromycin concentrations were determined using a validated UPLC-MS/MS method. The population pharmacokinetic model was structured using Phoenix NLME. The adequacy and robustness of the model was evaluated using VPC and bootstrap. We optimized azithromycin's dosing regimen for injection through Monte Carlo simulations. We included 254 plasma concentration data from 148 patients to establish the model. The clearance and volume were 1.27 L/h/kg and 45.6 L/kg, respectively. The covariates included were weight and age. VPC plots and nonparametric bootstrap showed that the final PPK model was reliable and robust. Based on Monte Carlo simulation, we derived a simple and practical dosing scheme. The results provided reference for individualized dosing in this population. The individualized dosing scheme based on Monte Carlo simulation can optimize clinical decision-making and guide personalized therapy.

Pharmacokinetic characteristics of azithromycin in freshwater crocodiles (Crocodylus siamensis) after intramuscular administration at three different dosages.

The study evaluated the pharmacokinetic features of azithromycin (AZM) in 15 freshwater crocodiles (Crocodylus siamensis) in Thailand. The crocodiles were administered a single intramuscular (i.m.) injection of AZM at three different dosages of 2.5, 5, and 10 mg/kg body weight (b.w.). Blood samples were collected at pre-assigned times up to 168 h. The plasma concentrations of AZM were measured using a validated liquid chromatography-tandem mass spectrometry method. The plasma concentration of AZM were quantifiable for up to 168 h after i.m. administration at the three different dosages. A non-compartmental model was used to fit the plasma concentration of AZM versus the time curve for each crocodile. The elimination half-life values of AZM were 33.70, 38.11, and 34.80 h following i.m. injection after dosages of 2.5, 5, and 10 mg/kg b.w., respectively. There were no significant differences among groups. The results indicated that the overall rate of elimination of AZM in freshwater crocodiles was relatively slow. The maximum concentration and area under the curve from zero to the last values of AZM increased in a dose-dependent fashion. The average binding percentage of AZM to plasma protein was 48.66%. Based on the pharmacokinetic data, the susceptibility break-point and the surrogate PK-PD index (T > MIC), the intramuscular administration of AZM at a dose of 10 mg/kg b.w. might be appropriate for the treatment of susceptible bacterial infections (MIC < 4 µg/ml) in freshwater crocodiles.

Impact of Azithromycin on Forsythiaside Pharmacokinetics in Rats: A Population Modeling Method.

OBJECTIVE: Lianhuaqingwen and Shuanghuanglian are drug treatment options for Corona Virus Disease 2019 (COVID-19). In China, use of traditional Chinese medicine with Shuanghuanglian or Lianhuaqingwen (for them, forsythiaside is the active antiviral and antibacterial component) in combination with azithromycin is common for the treatment of pediatric pneumonia. It is important to understand the reason why the combination of these compounds is better than a single drug treatment. This study aimed to explore the pharmacokinetic interaction between forsythiaside and azithromycin. METHODS: Twelve male Sprague-Dawley rats were randomly divided into an experimental group (Forsythia suspensa extract and azithromycin) and a control group (a single dose of Forsythia suspensa extract in 5% glucose solution). Plasma samples were collected at scheduled time points, and the high-performance liquid chromatography combined with ultraviolet method was used to determine the plasma forsythiaside concentration. Non-compartmental analysis and population pharmacokinetic methods were used to investigate the forsythiaside pharmacokinetic difference between the experimental and control group. RESULTS: Compared with a single administration, the area under the curve and half-life of forsythiaside increased, and forsythiaside clearance decreased significantly after co-administration with azithromycin. The in vivo behavior of forsythiaside could be described by the one compartment model. The forsythiaside clearance decreased when combined with azithromycin. Visual evaluation and bootstrap results suggested that the final model was precise and stable. CONCLUSION: Co-administration of azithromycin can significantly decrease the forsythiaside clearance and increase drug exposure. A lower dose of azithromycin can obtain sufficient forsythiaside concentration to provide antiviral and antibacterial activity.

Hydroxychloroquine and azithromycin used alone or combined are not effective against SARS-CoV-2 ex vivo and in a hamster model.

Drug repositioning has been used extensively since the beginning of the COVID-19 pandemic in an attempt to identify antiviral molecules for use in human therapeutics. Hydroxychloroquine and azithromycin have shown inhibitory activity against SARS-CoV-2 replication in different cell lines. Based on such in vitro data and despite the weakness of preclinical assessment, many clinical trials were set up using these molecules. In the present study, we show that hydroxychloroquine and azithromycin alone or combined does not block SARS-CoV-2 replication in human bronchial airway epithelia. When tested in a Syrian hamster model, hydroxychloroquine and azithromycin administrated alone or combined displayed no significant effect on viral replication, clinical course of the disease and lung impairments, even at high doses. Hydroxychloroquine quantification in lung tissues confirmed strong exposure to the drug, above in vitro inhibitory concentrations. Overall, this study does not support the use of hydroxychloroquine and azithromycin as antiviral drugs for the treatment of SARS-CoV-2 infections.

Minimum inhibitory concentration (MIC) of Ceftriaxone and Azithromycin for blood culture isolates of Salmonella enterica spp.

INTRODUCTION: Enteric fever caused by Salmonella enterica continues to be a major public health problem worldwide. In the last decade, ceftriaxone and azithromycin have become the drugs of choice for treating enteric fever caused by Nalidixic acid resistant Salmonella (NARS) enterica. This has led to reports of drug resistance to both drugs. Since enteric fever is endemic in India, accurate drug susceptibility surveillance is crucial to ensure empiric management of enteric fever is appropriate. The aim of this study is to evaluate the minimum inhibitory concentration (MIC) of ceftriaxone and azithromycin for blood culture isolates of NARS isolated at our centre. METHODOLOGY: This is a retrospective study conducted in a tertiary care center in Mumbai for blood culture isolates of NARS from 2016 to 2018. Isolates were tested for antimicrobial susceptibility testing (AST) against ceftriaxone and azithromycin using a manual broth microdilution method (BMD). RESULTS: Of 155 blood culture isolates of NARS: S. Typhi (n = 112) and S. Paratyphi A (n = 43) were included in the study. 81.9% (127 / 155) isolates were susceptible, 6.4% (10 / 155) isolates were intermediate while 11.6% (18 / 155) isolates were resistant to ceftriaxone. 100% susceptibility of NARS was observed to azithromycin. CONCLUSIONS: This study documents an alarming increase in resistance to ceftriaxone among NARS in Mumbai while azithromycin continues to be susceptible in vitro. It is essential to know MICs to understand epidemiological trends and choose appropriate treatment regimens for treating enteric fever.

Pharmacokinetics of oral antimycobacterials and dosing guidance for Mycobacterium avium complex treatment in cystic fibrosis.

BACKGROUND: Treatment failure of Mycobacterium avium complex (MAC) pulmonary disease occurs in about 30% of people with cystic fibrosis (CF) and may be a result of abnormal drug concentrations. METHODS: Prospective, cross-over, single-dose PK study of 20 pancreatic insufficient individuals with CF and 10 healthy controls (HC). CF subjects received simultaneous doses of oral azithromycin, ethambutol, and rifampin in the fasting state and with food and pancreatic enzymes, separated by two weeks. HC received fasting doses only. A non-compartmental model was used to estimate PK parameters of drugs and metabolites. RESULTS: Azithromycin maximum concentration (Cmax ) was higher and rifampin Cmax was lower in fasting CF subjects compared to HC, while other PK measures, including those for ethambutol, were similar. Addition of food and enzymes did not improve the Cmax of the antimycobacterial drugs. Nineteen of 20 CF subjects had one or more abnormal Cmax z-scores in either the fasting or fed state (or both), when compared to HC. CONCLUSION: PK profiles of azithromycin and ethambutol were similar between CF and HC, except azithromycin Cmax was slightly higher in people with CF after a single dose. Rifampin PK parameters were altered in persons with CF. Addition of food and enzymes in CF subjects did not improve PK parameters. Standard dosing guidelines should be used as a starting point for people with CF initiating MAC therapy and therapeutic drug monitoring should be routinely performed to prevent the possibility of treatment failure due to abnormal drug concentrations. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02372383 Prior abstract publication: 1. Martiniano S, Wagner B, Brennan L, Wempe M, Anderson P, Nick J, Sagel S. Pharmacokinetics of oral MAC antibiotics in cystic fibrosis. Am J Resp Crit Care Med A4842-A4842, 2017. 2. Martiniano SL, Wagner BD, Brennan L, Wempe MF, Anderson PL, Nick JA, Sagel SD. Pharmacokinetics of oral MAC antibiotics in cystic fibrosis. J Cyst Fibros 16: S52-53, 2017.

Antibiofilm Effects of Macrolide Loaded Microneedle Patches: Prospects in Healing Infected Wounds.

AIM: The aim of this study was to fabricate polymeric microneedles, loaded with macrolides (erythromycin, azithromycin), using hyaluronic acid and polyvinyl pyrollidone. METHODS: These microneedles were fabricated using a vacuum micromolding technique. The integrity of the microneedle patches was studied by recording their morphologic features, folding endurance, swelling and micro-piercing. Physicochemical characteristics were studied by differential scanning calorimetry, thermogravimetric analysis and fourier transform infrared spectroscopy. In-vitro drug release, antibiofilm and effect of microneedle patch on wound healing were also studied to confirm the efficacy of the formulations. RESULTS: Formulated patches displayed acceptable folding endurance (>100) and uniform distribution of microneedles (10 × 10) that can penetrate parafilm. Differential scanning calorimetry results depict a decrease in the crystallinity of macrolides following their incorporation in to a polymer matrix. Percentage release of azithromycin and erythromycin from the polymeric patch formulations (over 30 min) was 90% and 63% respectively. Broadly, the zone of bacterial growth inhibition follows the same order for Staphylococcus aureus, Escherichia coli and Salmonella enterica. After 5 days of treatment with azithromycin patches, the wound healing was complete and skin structure (e.g. hair follicles and dermis) was regenerated. CONCLUSION: It was concluded that azithromycin loaded microneedle patches can be used to treat biofilms in the infected wounds.

Demographic and behavioural factors associated with antimicrobial susceptibility to azithromycin and ceftriaxone in Neisseria gonorrhoeae.

Antimicrobial resistance of Neisseria gonorrhoeae (NG) is of global public health concern. The aim of this study was to explore demographic and behavioural factors associated with antimicrobial susceptibility of NG to ceftriaxone and azithromycin. Gonococcal isolates (n = 391) from clients attending the Auckland Sexual Health Service, New Zealand, from July 2014 - June 2015 (n = 206), and July 2017 - June 2018 (n = 185), were tested for susceptibility to ceftriaxone and azithromycin. Laboratory data were linked with behavioural and demographic data. Geometric mean azithromycin MICs increased across the two time periods (0.239 mg/L in 2014/15 to 0.347 mg/L in 2017/18, p < 0.001), and ceftriaxone MICs decreased (0.007 mg/L in 2014/15 to 0.005 mg/L in 2017/18, p < 0.001). Demographic and behavioural factors were not associated with differences in ceftriaxone MICs; however azithromycin MICs were higher in men who have sex with men (0.356 mg/L) compared with the heterosexual study population (0.192 mg/L, p < 0.001) and were lower in Pacific peoples (0.201 mg/L, p < 0.001) and Maori (0.244 mg/L, p = 0.05) compared with those of European ethnicity (0.321 mg/L). Our findings show that azithromycin MICs increased in our region between 2014 and 2018; associations were seen with sexual orientation and ethnicity.

A LC-MS/MS validated method for determination of azithromycin in human tears and its application to an ocular pharmacokinetic study.

A rapid and sensitive method for the quantitative analysis of azithromycin in human tears by LC-MS/MS was developed and validated. Following extraction from collected Schirmer tear strips by methanol-water (4:1, v/v), the analyte and IS (azithromycin-d3) were separated on a Waters Atlantis™ dC18 column (2.1 mm × 30 mm, 3 µm) by gradient elution with 0.1% (v/v) formic acid in methanol-water (1:9) and methanol-acetonitrile (9:1) as the mobile phase. Electrospray ionization in positive ion mode and MRM were used to monitor the ion transitions at m/z 749.6 → 591.6 (azithromycin) and 752.4 → 594.4 (azithromycin-d3). The results indicated that the method had excellent sensitivity and specificity. The analyte appeared to have good linearity in the range of 5-1000 ng/ mL. Both the intra-batch and inter-batch precisions (in terms of RSD) were <10%, and the accuracies (in terms of RE) were within ±15%. The lower limit of quantification, matrix effect, extraction recovery, stability and dilution integrity were also evaluated and satisfied the validation criteria. Artificial tears served as the surrogate matrix, and no matrix difference was found when compared with that of real human tears. Finally, this method was successfully applied in an ocular pharmacokinetic study in healthy volunteers following instillation of azithromycin eyedrops.

Disposition and pharmacokinetics of azithromycin in serum and a lung tissue of two modified-release formulations compared with an immediate-release product on the market.

The aim of this study was to determine the disposition and pharmacokinetics in serum and a lung tissue homogenate in guinea pig (Cavia porcellus) of two experimental formulations of azithromycin, those were included in a modified release polymer matrix (MRF) after oral administration. The results obtained are compared with a commercial form of immediate release. 3 groups of animals were randomly formed in groups of 7 for control and 14 for each group of modified-release formulations (MRFs) were treated with a single dose of 8mg/kg of active principle. In lung tissue, comparisons of concentration of azithromycin, showed statistically significant differences between commercial product, MRF1 and MRF2. All pharmacokinetic parameters for MRF1 and MRF2 were significantly different with the exception of Cmax with respect to commercial product. The treatment of the animals with MRFs may have several benefits over treatment with azithromycin alone since could increase dosing interval for the two MRFs evaluated and reduce the frequency of application, patient stress levels and toxicological risks by accumulation of the active principle.

Combination treatments with hydroxychloroquine and azithromycin are compatible with the therapeutic induction of anticancer immune responses.

Amid controversial reports that COVID-19 can be treated with a combination of the antimalarial drug hydroxychloroquine (HCQ) and the antibiotic azithromycin (AZI), a clinical trial (ONCOCOVID, NCT04341207) was launched at Gustave Roussy Cancer Campus to investigate the utility of this combination therapy in cancer patients. In this preclinical study, we investigated whether the combination of HCQ+AZI would be compatible with the therapeutic induction of anticancer immune responses. For this, we used doses of HCQ and AZI that affect whole-body physiology (as indicated by a partial blockade in cardiac and hepatic autophagic flux for HCQ and a reduction in body weight for AZI), showing that their combined administration did not interfere with tumor growth control induced by the immunogenic cell death inducer oxaliplatin. Moreover, the HCQ+AZI combination did not affect the capacity of a curative regimen (cisplatin + crizotinib + PD-1 blockade) to eradicate established orthotopic lung cancers in mice. In conclusion, it appears that HCQ+AZI does not interfere with the therapeutic induction of therapeutic anticancer immune responses.

Existing highly accumulating lysosomotropic drugs with potential for repurposing to target COVID-19.

Given the speed of viral infection spread, repurposing of existing drugs has been given the highest priority in combating the ongoing COVID-19 pandemic. Only drugs that are already registered or close to registration, and therefore have passed lengthy safety assessments, have a chance to be tested in clinical trials and reach patients quickly enough to help in the current disease outbreak. Here, we have reviewed available evidence and possible ways forward to identify already existing pharmaceuticals displaying modest broad-spectrum antiviral activity which is likely linked to their high accumulation in cells. Several well studied examples indicate that these drugs accumulate in lysosomes, endosomes and biological membranes in general, and thereby interfere with endosomal pathway and intracellular membrane trafficking crucial for viral infection. With the aim to identify other lysosomotropic drugs with possible inherent antiviral activity, we have applied a set of clear physicochemical, pharmacokinetic and molecular criteria on 530 existing drugs. In addition to publicly available data, we have also used our in silico model for the prediction of accumulation in lysosomes and endosomes. By this approach we have identified 36 compounds with possible antiviral effects, also against coronaviruses. For 14 of them evidence of broad-spectrum antiviral activity has already been reported, adding support to the value of this approach. Presented pros and cons, knowledge gaps and methods to identify lysosomotropic antivirals, can help in the evaluation of many drugs currently in clinical trials considered for repurposing to target COVID-19, as well as open doors to finding more potent and safer alternatives.

QT Interval Prolongation Under Hydroxychloroquine/Azithromycin Association for Inpatients With SARS-CoV-2 Lower Respiratory Tract Infection.

Association between Hydroxychloroquine (HCQ) and Azithromycin (AZT) is under evaluation for patients with lower respiratory tract infection (LRTI) caused by the Severe Acute Respiratory Syndrome (SARS-CoV-2). Both drugs have a known torsadogenic potential, but sparse data are available concerning QT prolongation induced by this association. Our objective was to assess for COVID-19 LRTI variations of QT interval under HCQ/AZT in patients hospitalized, and to compare manual versus automated QT measurements. Before therapy initiation, a baseline 12 lead-ECG was electronically sent to our cardiology department for automated and manual QT analysis (Bazett and Fridericia's correction), repeated 2 days after initiation. According to our institutional protocol (Pasteur University Hospital), HCQ/AZT was initiated only if baseline QTc ≤ 480ms and potassium level> 4.0 mmol/L. From March 24th to April 20th 2020, 73 patients were included (mean age 62 ± 14 years, male 67%). Two patients out of 73 (2.7%) were not eligible for drug initiation (QTc ≥ 500 ms). Baseline average automated QTc was 415 ± 29 ms and lengthened to 438 ± 40 ms after 48 hours of combined therapy. The treatment had to be stopped because of significant QTc prolongation in two out of 71 patients (2.8%). No drug-induced life-threatening arrhythmia, nor death was observed. Automated QTc measurements revealed accurate in comparison with manual QTc measurements. In this specific population of inpatients with COVID-19 LRTI, HCQ/AZT could not be initiated or had to be interrupted in less than 6% of the cases.

Predictions of Systemic, Intracellular, and Lung Concentrations of Azithromycin With Different Dosing Regimens Used in COVID-19 Clinical Trials.

Azithromycin (AZ), a broad-spectrum macrolide antibiotic, is being investigated in patients with coronavirus disease 2019 (COVID-19). A population pharmacokinetic model was implemented to predict lung, intracellular poly/mononuclear cell (peripheral blood monocyte (PBM)/polymorphonuclear leukocyte (PML)), and alveolar macrophage (AM) concentrations using published data and compared against preclinical effective concentration 90% (EC90 ) for severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). The final model described the data reported in eight publications adequately. Consistent with its known properties, concentrations were higher in AM and PBM/PML, followed by lung tissue, and lowest systemically. Simulated PBM/PML concentrations exceeded EC90 following the first dose and for ~ 14 days following 500 mg q.d. for 3 days or 500 mg q.d. for 1 day/250 mg q.d. on days 2-5, 10 days following a single 1,000 mg dose, and for > 20 days with 500 mg q.d. for 10 days. AM concentrations exceeded the 90% inhibitory concentration for > 20 days for all regimens. These data will better inform optimization of dosing regimens for AZ clinical trials.

Impact of Disease on Plasma and Lung Exposure of Chloroquine, Hydroxychloroquine and Azithromycin: Application of PBPK Modeling.

We use a mechanistic lung model to demonstrate that accumulation of chloroquine (CQ), hydroxychloroquine (HCQ), and azithromycin (AZ) in the lungs is sensitive to changes in lung pH, a parameter that can be affected in patients with coronavirus disease 2019 (COVID-19). A reduction in pH from 6.7 to 6 in the lungs, as observed in respiratory disease, led to 20-fold, 4.0-fold, and 2.7-fold increases in lung exposure of CQ, HCQ, and AZ, respectively. Simulations indicated that the relatively high concentrations of CQ and HCQ in lung tissue were sustained long after administration of the drugs had stopped. Patients with COVID-19 often present with kidney failure. Our simulations indicate that renal impairment (plus lung pH reduction) caused 30-fold, 8.0-fold, and 3.4-fold increases in lung exposures for CQ, HCQ, and AZ, respectively, with relatively small accompanying increases (20 to 30%) in systemic exposure. Although a number of different dosage regimens were assessed, the purpose of our study was not to provide recommendations for a dosing strategy, but to demonstrate the utility of a physiologically-based pharmacokinetic modeling approach to estimate lung concentrations. This, used in conjunction with robust in vitro and clinical data, can help in the assessment of COVID-19 therapeutics going forward.

Excessive lysosomal ion-trapping of hydroxychloroquine and azithromycin.

A recent report identified significant reductions or disappearance of viral load in COVID-19 patients given a combination of hydroxychloroquine and azithromycin. The present communication discusses some common pharmacokinetic properties of these two drugs that may be linked to a potential underlying mechanism of action for these antiviral effects. The physicochemical properties of both hydroxychloroquine and azithromycin are consistent with particularly high affinity for the intracellular lysosomal space, which has been implicated as a target site for antiviral activity. The properties of both drugs predict dramatic accumulation in lysosomes, with calculated lysosomal drug concentrations that exceed cytosolic and extracellular concentrations by more than 50 000-fold. These predictions are consistent with previously reported experimentally measured cellular and extracellular concentrations of azithromycin. This is also reflected in the very large volumes of distribution of these drugs, which are among the highest of all drugs currently in use. The combination of hydroxychloroquine and azithromycin produces very high local concentrations in lysosomes. The clinical significance of this observation is unclear; however, the magnitude of this mechanism of drug accumulation via ion-trapping in lysosomes could be an important factor for the pharmacodynamic effects of this drug combination.

Clinical Pharmacology Perspectives on the Antiviral Activity of Azithromycin and Use in COVID-19.

Azithromycin (AZ) is a broad-spectrum macrolide antibiotic with a long half-life and a large volume of distribution. It is primarily used for the treatment of respiratory, enteric, and genitourinary bacterial infections. AZ is not approved for the treatment of viral infections, and there is no well-controlled, prospective, randomized clinical evidence to support AZ therapy in coronavirus disease 2019 (COVID-19). Nevertheless, there are anecdotal reports that some hospitals have begun to include AZ in combination with hydroxychloroquine or chloroquine (CQ) for treatment of COVID-19. It is essential that the clinical pharmacology (CP) characteristics of AZ be considered in planning and conducting clinical trials of AZ alone or in combination with other agents, to ensure safe study conduct and to increase the probability of achieving definitive answers regarding efficacy of AZ in the treatment of COVID-19. The safety profile of AZ used as an antibacterial agent is well established.1 This work assesses published in vitro and clinical evidence for AZ as an agent with antiviral properties. It also provides basic CP information relevant for planning and initiating COVID-19 clinical studies with AZ, summarizes safety data from healthy volunteer studies, and safety and efficacy data from phase II and phase II/III studies in patients with uncomplicated malaria, including a phase II/III study in pediatric patients following administration of AZ and CQ in combination. This paper may also serve to facilitate the consideration and use of a priori-defined control groups for future research.

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

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.