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Azithromycin and hydroxychloroquine in hospitalised patients with confirmed COVID-19–a randomised do

Updated: Sep 19, 2021

Azithromycin and hydroxychloroquine in hospitalized patients with confirmed COVID-19–a randomized double-blinded placebo-controlled trial

Abstract Background Combining the antibiotic azithromycin and hydroxychloroquine induces airway immunomodulatory effects, with the latter also having in vitro antiviral properties. This may improve outcomes in patients hospitalized for COVID-19. Methods Placebo-controlled double-blind randomized multicentre trial. Patients ≥18 years, admitted to hospital for≤48 h (not intensive care) with a positive SARS-CoV-2 RT-PCR test, were recruited. The intervention was 500 mg daily azithromycin for 3 days followed by 250 mg daily azithromycin for 12 days combined with 200 mg twice daily hydroxychloroquine for all 15 days. The control group received a placebo/placebo. The primary outcome was days alive and discharged from the hospital within 14 days (DAOH14).

Azithromycin and hydroxychloroquine in hospitalised patients with confirmed COVID-19–a randomised double-blinded placebo-controlled trial Abstract

Results After randomization of 117 patients, at the first planned interim analysis, the data and safety monitoring board recommended stopping enrolment due to futility, based on pre-specified criteria. Consequently, the trial was terminated on February 1, 2021. A total of 61 patients received the combined intervention and 56 patients received placebo. In the intervention group, patients had a median of 9.0 DAOH14 (IQR, 3–11) versus. 9.0 DAOH14 (IQR, 7–10) in the placebo group (p=0.90). The primary safety outcome, death from all causes on day 30, occurred for 1 patient in the intervention group versus. 2 patients receiving placebo (p=0.52), and readmittance or death within 30 days occurred for 9 patients in the intervention group versus. 6 patients receiving placebo (p=0.57). Conclusions The combination of azithromycin and hydroxychloroquine did not improve survival or length of hospitalization in patients with COVID-19.

There are no beneficial or harmful effects from the combined intervention of hydroxychloroquine and azithromycin for hospitalized patients with confirmed coronavirus disease 2019 (COVID-19).

Introduction Early in the coronavirus disease 2019 (COVID-19) pandemic, some evidence, mainly from laboratory studies, suggested that chloroquine and its less toxic derivative hydroxychloroquine, often used as an antirheumatic drug, had an antiviral effect on coronaviridae by inhibiting several pH-dependent steps in replication and endosomal viral uptake into human cells [1]. These findings have been confirmed in laboratory studies of primate cells infected with severe acute respiratory syndrome coronavirus (SARS)-1 [2]. Hydroxychloroquine may also bind to host cell sialic acids and gangliosides with high affinity, thus protecting the cell against binding to SARS-Corona virus-2 via its spike (S) protein [3]. Administered at recommended doses, in most countries up to 400–500 mg daily, hydroxychloroquine seems safe, even when used for longer periods, and costs are low [4]. Azithromycin is a macrolide antibiotic, which has proven effective in reducing airway inflammation and consequent hospitalization-requiring exacerbations of Chronic Obstructive Pulmonary Disease (COPD), asthma, and bronchiectasis [57]. Recently, a strong association was found in critically ill patients with acute respiratory distress syndrome (ARDS) between treatment with azithromycin and improved survival [8] as summarised with greater power in systematic meta-analyses [9, 10]. Further, hydroxychloroquine and azithromycin may act synergistically to prevent the coronavirus from binding to ganglioside receptors on human cells [11]. Important trials show positive outcomes for agents like remdesivir, anti-IL6, and convalescent plasma in milder cases and early disease stages [1214] but these interventions seem less effective in severely ill patients [15]. On the other hand, in more severe cases, immunosuppressive pharmaceuticals like corticosteroids do show some effect [16]. Thus, antiviral treatment in the early, and less severe disease stages appears to be the window of opportunity for these drugs [17]. The present trial assessed whether a combination of azithromycin and hydroxychloroquine, both in moderate and approved (for rheumatic indications) dosing regimens, would increase the number of days alive and discharged from hospital among hospitalized patients with COVID-19.

Methods The trial protocol and statistical analysis plan are available in Supplementary Information sections 1 and 2 and have been published previously [18, 19]. The study was approved by the ethics committees of all participating sites (H-20022574), the Danish Medicines Agency (EudraCT no 2020-001198-55), and the Danish Data Protection Agency. It was monitored by good clinical practice (GCP) by the GCP units of the participating regions in Denmark. The study was conducted by the Declaration of Helsinki [20] No financial incentive was provided to the investigators or participants. There was an independent data and safety monitoring board (DSMB), consisting of three clinicians and researchers who are experts in performing large randomized studies. Additionally, the DSMB had access to the trial statistician, Mr. Tobias Wirenfeldt Klausen, a highly-skilled biostatistician, who also supervised the interim analyses. Mr. Klausen was available any time the DSMB wanted his input. He was also blinded to treatment allocation, as only the trial pharmacist had the key to unblind. This DSMB reviewed the trial's progress and performed safety, efficacy, and data completeness evaluations during the trial. It was not possible (in the interest of timeliness) to involve patients or the public in the design, conduct, reporting, or dissemination of our research. This study is a primary analysis and is described by the consolidated standards of reporting of randomized trials (CONSORT) guidelines. Study design and sites The Proactive Protection with Azithromycin and hydroxyChloroquine in hospitalized patients with COVID-19 (ProPAC-COVID) study was a multicentre, double-blinded placebo-controlled, randomized clinical trial investigating whether adding 15-day treatment with azithromycin and hydroxychloroquine to the standard of care could decrease the period of hospitalization and reduce the risks of non-invasive ventilation (NIV), admittance to an intensive care unit (ICU), and death. Patients were enrolled between April 6, 2020, and December 21, 2020, at six hospitals in Denmark within the COP: TRIN collaboration (www.captain.DK). The dosages selected were based on well-tolerated doses used to treat other diseases (e.g. rheumatological diseases), while lowering the risk of cardiac side effects. The durations were selected to ensure coverage of patients with prolonged admissions for a relatively large part of the admissions and to securely cover the entire observation period of the primary outcome. Also, durations were chosen to protect against secondary infections from Gram-positive microorganisms. Participants Eligible patients had to be 1) at least 18 years of age, 2) admitted to hospital with a confirmed positive test for SARS-CoV-2 infection by reverse transcription-polymerase chain reaction (RT-PCR), and 3) hospitalized for≤48 h. Each patient provided signed informed consent to participate. Patients were excluded if they met any of the following criteria: 1) received>5 L oxygen supply; 2) known intolerance/allergy to the study drugs; 3) neurogenic hearing loss; 4) psoriasis; 5) retinopathy; 6) maculopathy; 7) visual field changes; 8) were breastfeeding/pregnant; 9) severe liver disease (international normalised ratio>1.5 spontaneously); 10) severe gastrointestinal disease (investigator-assessed liver disease, severe ulcerative colitis or Crohn's disease, peptic ulcer disease, or cancer); 11) neurological or haematological disorder; 12) estimated glomerular filtration rate (eGFR)<45 mL·min·1.73 m2; 13) clinically significant cardiac conduction disorder/arrhythmia or a prolonged corrected QT interval (QTc; i.e., F>480 ms for males or>470 ms for females); 14) myasthenia gravis; 15) were receiving treatment with digoxin; 16) glucose-6-phosphate dehydrogenase deficiency; 17) porphyria; 18) hypoglycaemia (blood glucose<3.0 mmol/L–1); 19) unable to give informed consent; 20) severe linguistic problems that significantly hindered cooperation; or 21) were receiving treatment with ergot alkaloids. The investigator evaluated patient eligibility based on these criteria. Randomization and masking The study pharmacist generated the randomization sequence, which was then entered into the online platform REDCap electronic data capture tools hosted by the participating Danish regions. Patients were randomized 1:1 to azithromycin plus hydroxychloroquine or matching placebo capsules. Randomization was performed in blocks of unknown and varying size, and the final allocation was blinded and stratified for age (> 70 versus ≤ 70 years), site of recruitment, and whether the patient had any of the following chronic lung diseases (yes versus no): COPD, asthma, bronchiectasis, or interstitial lung disease. All patients and study staff were blinded to participant treatment assignments. This included outcome assessors, investigators, and study nurses, as well as research and clinical staff. The DSMB remained blinded throughout and made all recommendations blinded to treatment allocations. Only the trial's chief pharmacist held the key for unblinding. Formal unblinding took place on February 1, 2021, after the DSMB recommendation had been received and acknowledged. Intervention Patients were randomized to one of two treatment arms: 1) 500 mg azithromycin once daily plus 200 mg hydroxychloroquine twice daily on days 1–3 and then 250 mg azithromycin once daily plus 200 mg hydroxychloroquine twice daily on days 4–15; 2) placebo instead of both types of intervention medication. Medication (both arms) was marked with neutral labels: e.g., “Azithromycin group A” and “Azithromycin group B”. An important safety consideration for both study drugs was QTc prolongation Therefore, trial personnel measured the QTc at least twice during the period of hospitalization. Primary and secondary endpoints The primary endpoint was the number of days alive and out of hospital (DAOH) within 14 days from randomization. This outcome measure was developed by trialists to be both sensitive and clinically relevant, and it provides a method for counting days with sustained recovery without lead-time bias–For the first secondary endpoint, each patient was placed in one of the following eight categories on day 5 and day 15, as described in our previous research [: 1) discharged from hospital with no restrictions on activities; 2) discharged from hospital but with restrictions on activities (may/may not be receiving long-term oxygen therapy at home); 3) hospitalised and under observation but not receiving supplemental oxygen or any other treatment; 4) hospitalised and not receiving supplemental oxygen, but receiving other treatment (which may/may not be related to COVID-19); 5) hospitalised and receiving supplemental oxygen by a method other than those described in (2) or (3), such as from a nasal catheter; 6) hospitalised and receiving NIV or oxygen from a high-flow device; 7) hospitalised and receiving mechanical ventilation or extracorporeal membrane oxygenation; or 8) dead. The trial included eight other secondary outcomes: 1) several days in an ICU (time frame: 14 days); 2) several days NIV was required during hospitalization (time frame: 14 days); 3) mortality rates (time frames: 30, 90, and 365 days); 4) length of hospitalization (time frame: 14 days); 5) DAOH (time frame: 30 days); 6) time to readmission for any reason (time frame: 30 days); 7) change in patient's pH, PaO2, or PCO2 partial pressure measurements (time frame: 4 days); and 8) time until no supplementary oxygen was required or until the patient was given “long-term oxygen therapy” (time frame: 14 days). Outcomes with follow-up >30 days will be reported later. All outcomes and analyses were conducted in strict concordance with the SAP. Sample size calculation The sample size for the primary outcome (DAOH within 14 days from randomization) was calculated assuming a two-sided significance level of 5% and power (1 – β) of 80%. A group-sequential study design with one planned interim analysis at half-target recruitment was used. The standard deviation was set at 4 days [ and the detection limit was set at 1.5 days (both directions). StudySize software (ver. 3.0; CreoStat HB, Gothenburg, Sweden) was used to calculate the sample size of 226 participants. Statistical analysis We compared outcomes using t-tests or Mann–Whitney U tests for continuous variables (depending on distribution), χ2 tests or Fisher's exact test for nominal variables, and log-rank tests to compare Kaplan–Meier survival curves. Cumulative event estimates were generated using hazard ratios (HRs) with 95% confidence intervals (CIs) in Cox proportional hazards models. Adjustment for continuous data was performed using multiple effects models. The primary analysis was based on intention-to-treat (ITT), and a secondary per-protocol analysis was performed for both primary and secondary outcomes. A p-value<0.05 was considered statistically significant and all analyses were two-sided. We originally planned to perform an interim analysis between the groups when the study had reached 50% of the total sample size. However, in response to a subsequently retracted article by Mehra et al. [], the Danish Medicines Agency demanded that we performed an extraordinary acute interim analysis (without unmasking) on the first 75 patients who had been recruited. This was reviewed by the DSMB, who recommended continuing to accrue patients (May 2020). The first planned interim analysis was conducted on 117 patients (50% recruited), and the trial was stopped due to futility (February 2021). Sensitivity analyses for the primary outcome included: 1) a modified ITT population of patients who received part or complete treatment with the intervention (all days); 2) a per-protocol population who received both interventional drugs for all planned days; and 3) multiple effects adjusted model for the primary outcome, in which adjustment was made for the following parameters: i) age (per year increase), ii) sex (male versus female), iii) body mass index (per unit increase), iv) oxygen therapy at inclusion (yes versus no), v) remdesivir (yes versus no), vi) any pre-existing lung disease (obstructive, interstitial or bronchiectasis: yes versus no), vii) diabetes mellitus (yes versus no), and viii) QTc across median (yes versus no). Statistical analyses were performed using SAS software (ver. 9.4; SAS Institute, Inc., Cary, NC, USA) and R software (ver. 3.4.3; R Development Core Team, Vienna, Austria). Stopping the trial On February 1, 2021, the trial was stopped for futility based on recommendations from the DSMB who met on January 29, 2021, and discussed the report from the first planned interim analysis. The maximum post conditional power to cross any boundary in the O'Brien–Fleming plot was 0.064, which was below the threshold of 0.2 communicated from the steering committee to the DSMB before the meeting. The interim analyses were performed by the trial monitoring guidelines. After reviewing the post-conditional power, the remaining data in the interim analysis, and the available published data, the DSMB recommended stopping the trial on grounds of futility (the DSMB recommendation is included in Supplementary Information section 4).

Results Of the 664 patients screened, 117 were eligible for study inclusion (figure 1). Reasons for exclusion included: unable to give informed consent (18.8% of exclusions), eGFR<45 mL·min·1.73 m2 (17.9% of exclusions) and declined to participate (16.3% exclusions). Of the patients enrolled, 61 patients were randomized to the azithromycin plus hydroxychloroquine arm and 56 to the placebo arm. Participants had a median age of 65 years (interquartile range [IQR], 52–77), and 65 (56%) of them were men. The median time since symptom onset was 8 days (IQR, 4–10). Baseline characteristics of patients randomized to the intervention and placebo groups are presented in table 1 and in eTable 1 and eTable 2 in Supplementary Information section 3 Primary and secondary outcomes Primary outcome Primary outcome assessment after randomization was completed for 117 patients (100%). We observed no significant difference between the two randomized groups for the primary outcome of DAOH within 14 days after recruitment: median of 9.0 DAOH14 (IQR, 3–11) in the hydroxychloroquine plus azithromycin group versus 9.0 DAOH14 (IQR, 7–10) in the placebo group, p=0.91 (table 2, figure 2). FIGURE 2Days alive and out of the hospital at 14 days and 30 days, median (IQR), days. Secondary outcomes At 15 days after randomization, there was no significant difference between the hydroxychloroquine plus azithromycin group and the placebo group in COVID Outcomes Scale score (OR, 1.0 [95% CI, 0.5–2.2]; p=0.91; figure 3 and eTable 6 in Supplementary Information section 3). A post-doc analysis of the ordinal outcome at day 5 was requested by the steering committee after unblinding to provide a time-updated assessment of clinical status; this analysis also suggested that the two groups were similar (OR, 0.9 [95% CI, 0.4–1.8]; figure 3 and eTable 7 in Supplementary Information section 3). We also found no differences between the groups in the prespecified subsidiary clinical outcomes (table 2, figure 2). We tested for an interaction between the trial intervention and symptom duration (< 8 days versus 8 days or above) and found no interaction (p=0.79). FIGURE 3Days alive and out of the hospital at 14 days and 30 days, median (IQR), days. Adverse event data are presented in table 3 and table 8 in Supplementary Information section 3. During follow-up, 1 of 61 patients (1.64%) in the hydroxychloroquine plus azithromycin group and 2 of 56 patients (3.6%) in the placebo group had a recorded QTc greater than 500 ms (Table 2). Adverse events involving diarrhea (12 versus 3), nausea (11 versus 6), and dizziness (10 versus 3) were more frequent in the hydroxychloroquine plus azithromycin patient group than in the placebo group. Conversely, adverse events involving a prolonged QTc (> 470 ms for females and>480 ms for males) were more frequent in the placebo group (4 versus 7). Only 2 serious adverse events were reported, both in the placebo group (eTable 8 in Supplementary Information section 3).


The ProPAC-COVID trial was stopped at half recruitment based on prespecified futility criteria after a recommendation from the DSMB, in agreement with monitoring guidelines. Compared to placebo, the combination of azithromycin and hydroxychloroquine did not seem to have any effect on the measured outcomes. The primary outcome, DAOH within 14 days from randomization, was similar in both arms, as was the ordinal outcome measure and the rates of death from all causes and readmissions.

Our trial is the first to report on this combination of hydroxychloroquine plus azithromycin administered in normally recommended doses for 15 days versus placebo. Other trials have reported either a mono-drug intervention versus placebo or higher doses of hydroxychloroquine plus azithromycin versus. one of these drugs.


Azithromycin and hydroxychloroquine in hospitalised patients with confirmed COVID-19–a randomised double-blinded placebo-controlled trial Abstract

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