Remdesivir treatment in hospitalized patients with COVID-19: a comparative analysis of in-hospital all-cause mortality in a large multi-center observational cohort

Background

Remdesivir (RDV) improved clinical outcomes among hospitalized patients with coronavirus disease 2019 (COVID-19) in randomized trials, but data from clinical practice are limited.

Methods

We examined survival outcomes for US patients hospitalized with COVID-19 between August and November 2020 and treated with RDV within 2 days of hospitalization vs those not receiving RDV during their hospitalization using the Premier Healthcare Database. Preferential within-hospital propensity score matching with replacement was used. Additionally, patients were also matched on baseline oxygenation level (no supplemental oxygen charges [NSO], low-flow oxygen [LFO], high-flow oxygen/noninvasive ventilation [HFO/NIV], and invasive mechanical ventilation/extracorporeal membrane oxygenation [IMV/ECMO]) and 2-month admission window and excluded if discharged within 3 days of admission (to exclude anticipated discharges/transfers within 72 hours, consistent with the Adaptive COVID-19 Treatment Trial [ACTT-1] study). Cox proportional hazards models were used to assess time to 14-/28-day mortality overall and for patients on NSO, LFO, HFO/NIV, and IMV/ECMO.

Results

A total of 28855 RDV patients were matched to 16687 unique non-RDV patients. Overall, 10.6% and 15.4% RDV patients died within 14 and 28 days, respectively, compared with 15.4% and 19.1% non-RDV patients. Overall, RDV was associated with a reduction in mortality at 14 days (hazard ratio [95% confidence interval]: 0.76 [0.70–0.83]) and 28 days (0.89 [0.82–0.96]). This mortality benefit was also seen for NSO, LFO, and IMV/ECMO at 14 days (NSO: 0.69 [0.57–0.83], LFO: 0.68 [0.80–0.77], IMV/ECMO: 0.70 [0.58–0.84]) and 28 days (NSO: 0.80 [0.68–0.94], LFO: 0.77 [0.68–0.86], IMV/ECMO: 0.81 [0.69–0.94]). Additionally, HFO/NIV RDV group had a lower risk of mortality at 14 days (0.81 [0.70–0.93]) but no statistical significance at 28 days.

Conclusions

RDV initiated upon hospital admission was associated with improved survival among patients with COVID-19. Our findings complement ACTT-1 and support RDV as a foundational treatment for hospitalized COVID-19 patients.

Remdesivir use and outcomes during the FDA COVID-19 emergency use authorization period

Background:

Remdesivir (RDV) was approved for treatment of coronavirus disease 2019 (COVID-19), in May 2020 under US Food and Drug Administration emergency use authorization (EUA). Clinical outcomes related to RDV use in hospitalized patients during the EUA period are not well described.

Methods:

We conducted a retrospective study of patients who received RDV under EUA. The primary outcome was clinical recovery by day 14 as determined by an eight-category ordinal scale. Secondary outcomes included recovery and survival to day 28, and adverse events. Recovery and survival were calculated using a stratified log-rank Kaplan–Meier estimator and a Cox proportional hazards model.

Results:

Overall, 164 patients received RDV between May and October 2020, and 153 (93.3%) had evaluable data. Most (77.1%) were hospitalized within 10 days of symptom onset, and 79.7% started RDV within 48 hours. By days 14 and 28, 96 (62.7%) and 117 patients (76.5%) met the definition of clinical recovery, respectively. Median time to recovery was 6 days [interquartile range (IQR) 4–12]. Mortality rates were 6.5% and 11.8% by days 14 and 28, respectively. Age and time to start of RDV after hospital admission were predictive of recovery and 28-day mortality.

Conclusions:

In this real-world experience, outcomes after 5 days of RDV therapy were comparable to those of clinical trials. Disease severity, age, and dexamethasone use influenced clinical outcomes. Time to RDV initiation appeared to affect recovery and 28-day mortality, a finding that should be explored further. Mortality rate decreased over the analysis period, which could be related to dexamethasone use and improved management of COVID-19.

Eicosanoid Metabolomic Profile of Remdesivir Treatment in Rat Plasma by High-Performance Liquid Chromatography Mass Spectrometry

Remdesivir, a nucleotide analog prodrug, has displayed pharmacological activity against SARS-CoV-2. Recently, eicosanoids are widely involved in regulating immunity and inflammation for COVID-19 patients. Rats were intravenously administered remdesivir at a dose of 5 mg/kg, and series of blood samples were collected before and after treatment. Targeted metabolomics regarding the eicosanoid profile were investigated and quantitated simultaneously using the previously reported reliable HPLC-MS/MS method. Additionally, interplay relationship between metabolomics and pharmacokinetic parameters was performed using the Pearson correlation analysis and PLS model. For the longitudinal metabolomics of remdesivir, metabolic profiles of the same rat were comparatively substantial at discrete sampling points. The metabolic fingerprints generated by individual discrepancy of rats were larger than metabolic disturbance caused by remdesivir. As for the transversal metabolomics, the prominent metabolic profile variation was observed between the baseline and treatment status. Except for TXB2, the inflammatory- and immunology-related eicosanoids of resolvin D2, 5-HEPE, 5-HETE, and DHA were significantly disturbed and reduced after single administration of remdesivir (p < 0.05, p < 0.001). Moreover, the metabolite of PGE2 correlated with GS-441524 (active metabolite of remdesivir) concentration and pharmacokinetic parameters of Cmax, AUC0-t, AUC0-infinity, and CL significantly. Eicosanoid metabolic profiles of remdesivir at both longitudinal and transversal levels were first revealed using the robust HPLC-MS/MS method. This initial observational eicosanoid metabolomics may lighten the therapy for fighting COVID-19 and further provide mechanistic insights of SARS-CoV-2 virus infection.

Legionella Coinfection in a Patient With COVID-19 Pneumonia

Bacterial superinfection is a well-reported complication of viral pneumonia leading to significantly increased morbidity and mortality. Such superinfections have been reported in patients with pathogenic coronaviruses including severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS), but there are scant reports pertaining to superinfection in the context of coronavirus disease 2019 (COVID-19). We report a case of a middle-aged man who presented with worsening shortness of breath in the context of COVID-19 complicated by superimposed Legionella pneumophilia pneumonia. This case serves to highlight the possibility of bacterial superinfections and to be aware of such possibilities when patients are not responding to standard courses of treatment for COVID-19 as quick clinical deterioration is likely to develop.

The safety, tolerability and mortality reduction efficacy of remdesivir; based on randomized clinical trials, observational and case studies reported safety outcomes: an updated systematic review and meta-analysis

INTRODUCTION

Remdesivir, an experimental antiviral drug has shown to inhibit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), both in vitro and in vivo. The present systematic review and meta-analysis were performed to quantify the safety and tolerability of remdesivir, based on safety outcome findings from randomized controlled trials, observational studies and case reports of remdesivir in coronavirus disease 2019 (COVID-19) patients.

METHODS

We have performed a systematic search in the PubMed, Google Scholar and Cochrane Library using specific keywords such as 'COVID-19' OR 'SARS CoV-2' AND 'Remdesivir'. The study endpoints include total adverse events (AEs), serious adverse events (SAEs), grade 3 and grade 4 AEs, mortality and drug tolerability. Statistical analysis was carried out by using Revman 5.4 software.

RESULTS

Total 15 studies were included for systematic review, but only 5 randomized clinical trials (RCTs) (n = 13,622) were included for meta-analysis. Visual inspection of the forest plots for remdesivir 10-day versus placebo and remdesivir 10-day versus 5-day groups revealed that there is a significant difference in SAEs [10-day remdesivir versus control (odds ratio [OR] = 0.55, 0.40-0.74) p = 0.0001; I 2 = 0%; 10-day remdesivir versus 5-day remdesivir (OR = 0.56, 0.38-0.84) p = 0.005; I 2 = 13%]. In grade 4 AEs, there is a significant difference in 10-day remdesivir versus control (OR = 0.32, 0.19-0.54) p = 0.0001; I 2 = 0%, but not in comparison to 5-day remdesivir (OR = 0.95, 0.59-1.54) p = 0.85; I 2 = 0%. But there is no significant difference in grade 3 AEs [remdesivir 10 day versus control (OR = 0.81, 0.59-1.11) p = 0.19; I 2 = 0%; 10-day remdesivir versus 5-day remdesivir (OR = 1.24, 0.86-1.80) p = 0.25; I 2 = 0%], in total AEs [remdesivir 10 day versus control (OR = 1.07, 0.66-1.75) p = 0.77; I 2 = 79%; remdesivir 10 day versus 5 day (OR = 1.08, 0.70-1.68) p = 0.73; I 2 = 54%)], in mortality [10-day remdesivir versus control (OR = 0.93, 0.80-1.08) p = 0.32; I 2 = 0%; 10-day remdesivir versus 5-day remdesivir (OR = 1.39, 0.73-2.62) p = 0.32; I 2 = 0%)] and tolerability [remdesivir 10 day versus control (OR = 1.05, 0.51-2.18) p = 0.89; I 2 = 65%, 10-day remdesivir versus 5-day remdesivir (OR = 0.86, 0.18-4.01) p = 0.85; I 2 = 78%].

DISCUSSION & CONCLUSION

Ten-day remdesivir was a safe antiviral agent but not tolerable over control in the hospitalized COVID-19 patients with a need of administration cautiousness for grade 3 AEs. There was no added benefit of 10- or 5-day remdesivir in reducing mortality over placebo. To avoid SAEs, we suggest for prior monitoring of liver function tests (LFT), renal function tests (RFT), complete blood count (CBC) and serum electrolytes for those with preexisting hepatic and renal impairments and patients receiving concomitant hepatotoxic or nephrotoxic drugs. Furthermore, a number of RCTs of remdesivir in COVID-19 patients are suggested.

PLAIN LANGUAGE SUMMARY

Ten-day remdesivir is a safe antiviral drug with common adverse events in comparison to placebo.The rate of serious adverse events and grade 3 adverse events were significantly lower in 10-day remdesivir in comparison to placebo/5-day remdesivir.There was no significant difference in the rate of tolerability and mortality reduction in 10-day remdesivir over placebo/5-day remdesivir.There were no new safety signals reported in vulnerable populations, paediatric, pregnant and lactating women.

Pharmacology and Adverse Events of Emergency-Use Authorized Medication in Moderate to Severe COVID-19

Some effective drugs have been approved or issued an Emergency Use Authorization for the treatment of COVID-19 in hospitalized patients, but post-market surveillance is warranted to monitor adverse events. We reviewed clinical trials and case reports in patients with moderate-to-severe COVID-19 infection who received remdesivir, baricitinib, tocilizumab, or sarilumab. The drug-specific pharmacokinetics, toxicity, and drug interactions are summarized in this study. Remdesivir and baricitinib are small-molecule drugs that are mainly metabolized by the kidneys, while tocilizumab and sarilumab are monoclonal antibody drugs with metabolic pathways that are currently not fully understood. The most common adverse events of these drugs are alterations in liver function, but serious adverse events have rarely been attributed to them. Only a few studies have reported that remdesivir might be cardiotoxic and that baricitinib might cause thromboembolism. Biological agents such as baricitinib, tocilizumab, and sarilumab could inhibit the pathway of inflammatory processes, leading to immune dysregulation, so the risk of secondary infection should be assessed before prescribing. Further recognition of the pathogenic mechanism and risk factors of adverse events is essential for optimizing treatment strategies.

New-Onset Psychosis Following COVID-19 Infection

Previous studies have suggested that some individuals experience neuropsychiatric symptoms following coronavirus disease 2019 (COVID-19) infection. We describe a case of new-onset psychosis following COVID-19 infection in a 55-year-old female with no prior psychiatric history. The patient started exhibiting symptoms of COVID-19 infection three weeks prior and was treated in the hospital with 4 L oxygen, dexamethasone 6 mg, and remdesivir therapy for seven days. Throughout her hospital stay, the patient had no neuropsychiatric symptoms. During her last week of stay, she was solely getting oxygen at home before presenting to the emergency department (ED) with severe psychosis. Her COVID-19 test in ED presentation was negative, and all potential etiologies for psychosis were ruled out. She was effectively treated for two weeks with 10 mg haloperidol and 1000 mg sodium valproate daily, followed by outpatient care. While variables such as a family history of bipolar disorder, psychosocial stressors, and steroid medication may have contributed to the patient's presentation, these circumstances alone did not result in neuropsychiatric symptoms in the past. COVID-19 infection may enhance the likelihood of developing neuropsychiatric problems on its own or amplify the effects of risk factors associated with an increased risk of psychosis. Neuropsychiatric consequences of COVID-19 infection may be under- or over-reported in individuals treated with steroids. Further research is necessary to identify individuals at risk of experiencing neuropsychiatric issues owing to COVID-19 infection and the prognosis.

Renal and Hepatic Toxicity Analysis of Remdesivir Formulations: Does What Is on the Inside Really Count?

It has been postulated that the injectable solution formulation of remdesivir could be more nephrotoxic than the lyophilized powder since it contains twice as much sulfobutylether-β-cyclodextrin (SBECD). Therefore, we evaluated 1,000 hospitalized patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who received remdesivir lyophilized powder or solution. A logistic regression model accounting for baseline confounders identified that neither the use of the injectable solution (odds ratio [OR], 1.05; 95% confidence interval [CI], 0.49 to 2.29; P = 0.901) nor a creatinine clearance of <30 ml/min at the time of remdesivir initiation (OR, 1.39; 95% CI, 0.51 to 3.5; P = 0.499) was significantly associated with acute kidney injury. Regarding hepatoxicity, there was no significant difference in early discontinuation of remdesivir due to abnormal liver function tests between patients who received the lyophilized powder versus those who received solution (0.9% versus 2.3%, P = 0.09).

Real-world outcomes of COVID-19 treatment with remdesivir in a Spanish hospital

Remdesivir is the only antiviral approved for lower respiratory tract infection produced by SARS-CoV-2. The main objective of this study was to determine the mortality rate, readmissions, mean hospital stay, need for higher levels of oxygen support, and adverse effect-induced abandonment rate in hospitalized patients diagnosed with COVID-19 and treated with remdesivir (RDSV). The secondary objective was to determine mortality-related risk factors in these patients.The study included a prospective cohort of patients admitted to a third level Spanish hospital between July 5, 2020 and February 3, 2021 for COVID-19 diagnosed by SARS-CoV-2 polymerase chain reaction and/or antigen test and treated with RDSV.Remdesivir was received by 185 patients (69.7% males) with a mean age of 62.5 years, median Charlson index of 3 (interquartile range [IQR]: 1-4), and median ambient air oxygen saturation of 91% (IQR: 90-93); 61.6% of patients had hyper-inflammatory syndrome at admission. Median time with symptoms before RDSV treatment was 5 days (IQR: 3-6) and the median hospital stay was 10 days (IQR: 7-15); 19 patients (10.3%) died after a median stay of 13.5 days (IQR: 9.7-24 days), 58 patients (12.9%) were admitted to ICU, 58 (31.4%) needed higher levels of oxygen support, 0.5% abandoned the treatment due to adverse effects, and there were no readmissions. The only mortality-related factor was the need for higher levels of oxygen support (odds ratio 12.02; 95% confidence interval 2.25-64.2).All studied patients were admitted to hospital with a diagnosis of COVID-19 and in respiratory failure, needing initial low-flow oxygen support, and all received RDSV within 1 week of symptom onset. The percent mortality was lower in these patients than was observed in all patients with severe COVID-19 admitted to our center (10.3% vs 20.3%, respectively). Despite receiving RDSV, 1 in 3 patients needed higher levels of oxygen support, the sole mortality-related factor.

Rethinking Remdesivir: Synthesis, Antiviral Activity, and Pharmacokinetics of Oral Lipid Prodrugs

Remdesivir (RDV; GS-5734) is currently the only FDA-approved antiviral drug for the treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The drug is approved for use in adults or children 12 years or older who are hospitalized for the treatment of COVID-19 on the basis of an acceleration of clinical recovery for inpatients with this disease. Unfortunately, the drug must be administered intravenously, restricting its use to those requiring hospitalization for relatively advanced disease. RDV is also unstable in plasma and has a complex activation pathway which may contribute to its highly variable antiviral efficacy in SARS-CoV-2-infected cells. Potent orally bioavailable antiviral drugs for early treatment of SARS-CoV-2 infection are urgently needed, and several, including molnupiravir and PF-07321332, are currently in clinical development. We focused on making simple, orally bioavailable lipid analogs of remdesivir nucleoside (RVn; GS-441524) that are processed to RVn monophosphate, the precursor of the active RVn triphosphate, by a single-step intracellular cleavage. In addition to high oral bioavailability, stability in plasma, and simpler metabolic activation, new oral lipid prodrugs of RVn had submicromolar anti-SARS-CoV-2 activity in a variety of cell types, including Vero E6, Calu-3, Caco-2, human pluripotent stem cell (PSC)-derived lung cells, and Huh7.5 cells. In Syrian hamsters, oral treatment with 1-O-octadecyl-2-O-benzyl-glycero-3-phosphate RVn (ODBG-P-RVn) was well tolerated and achieved therapeutic levels in plasma above the 90% effective concentration (EC90) for SARS-CoV-2. The results suggest further evaluation as an early oral treatment for SARS-CoV-2 infection to minimize severe disease and reduce hospitalizations.

Anti-SARS-CoV-2 Activity of Extracellular Vesicle Inhibitors: Screening, Validation, and Combination with Remdesivir

The coronavirus disease 2019 (COVID-19) pandemic severely impacts health, economy, and society worldwide. Antiviral drugs against SARS-CoV-2 are urgently needed to cope with this global crisis. It has been found that the biogenesis and release mechanisms of viruses share a common pathway with extracellular vesicles (EVs). We hypothesized that small molecule inhibitors of EV biogenesis/release could exert an anti-SARS-CoV-2 effect. Here, we screened 17 existing EV inhibitors and found that calpeptin, a cysteine proteinase inhibitor, exhibited the most potent anti-SARS-CoV-2 activity with no apparent cytotoxicity. Calpeptin demonstrated the dose-dependent inhibition against SARS-CoV-2 viral nucleoprotein expression in the infected cells with a half-maximal inhibitory concentration (IC50) of 1.44 µM in Vero-E6 and 26.92 µM in Calu-3 cells, respectively. Moreover, calpeptin inhibited the production of infectious virions with the lower IC50 of 0.6 µM in Vero E6 cells and 10.12 µM in Calu-3 cells. Interestingly, a combination of calpeptin and remdesivir, the FDA-approved antiviral drug against SARS-CoV-2 viral replication, significantly enhanced the anti-SARS-CoV-2 effects compared to monotherapy. This study discovered calpeptin as a promising candidate for anti-SARS-CoV-2 drug development. Further preclinical and clinical studies are warranted to elucidate the therapeutic efficacy of calpeptin and remdesivir combination in COVID-19.

Current status of therapeutic alternatives for COVID-19: A narrative review

Since December 2019, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection has exploded and led to a global crisis. Currently, the global case numbers topped 200 million, and toll of dead exceeded 4 million around the world. The pathogenesis of coronavirus disease 2019 (COVID-19) is driven by two processes. During the first stage of the infection that lasts around 5-7 days, replication of SARS-CoV-2 occurs. In the second stage, the disease may progress due to an exaggerated inflammatory response leading to tissue damage. Therefore, it is anticipated that antiviral agents would be effective during the early phase of the disease, while immunomodulator agents are likely to be more beneficial in the second stage of COVID-19. This basic concept of disease development led to explore several antiviral and immunomodulator agents for the treatment of COVID-19. Currently, remdesivir is the only available Food and Drug Administration-approved antiviral agent for the treatment of COVID-19. However, some other agents have been approved by various mechanisms, including Emergency Use Authorizations, Emergency Investigational New Drug applications, compassionate use or expanded access programs. In addition, a variety of repurposed agents that were approved for other indications are being investigated for the treatment of COVID19 in clinical trials. A myriad of publications including randomized controlled trials (RCTs) are emerging continuously and are accessible as peer-reviewed, pre-print and press release formats. Considering the critical importance of RCTs in generating evidence and providing further guidance on COVID-19 treatment, we herein reviewed only RCTs and meta-analyses. The discussion includes antiviral agents (hydroxychloroquine, lopinavir/ritonavir, remdesivir, favipiravir and ivermectin) and, various immunomodulatory drugs (corticosteroids, tocilizumab, baricitinib, and IL-1 inhibitors). Other investigational therapies including darunavir/cobicistat, umifenovir, sofosbuvir/daclatasvir, sofobuvir/ledipasvir, ribavirin, nitazoxanide and interferon-based regimens were not evaluated due to insufficient data on the efficacy and safety of these agents.

Remdesivir and Cyclosporine Synergistically Inhibit the Human Coronaviruses OC43 and SARS-CoV-2

Remdesivir, a prodrug targeting RNA-dependent-RNA-polymerase, and cyclosporine, a calcineurin inhibitor, individually exerted inhibitory activity against human coronavirus OC43 (HCoV-OC43) in HCT-8 and MRC-5 cells at EC₅₀ values of 96 ± 34 ∼ 85 ± 23 nM and 2,920 ± 364 ∼ 4,419 ± 490 nM, respectively. When combined, these two drugs synergistically inhibited HCoV-OC43 in both HCT-8 and MRC-5 cells assayed by immunofluorescence assay (IFA). Remdesivir and cyclosporine also separately reduced IL-6 production induced by HCoV-OC43 in human lung fibroblasts MRC-5 cells with EC₅₀ values of 224 ± 53 nM and 1,292 ± 352 nM, respectively; and synergistically reduced it when combined. Similar trends were observed for SARS-CoV-2, which were 1) separately inhibited by remdesivir and cyclosporine with respective EC₅₀ values of 3,962 ± 303 nM and 7,213 ± 143 nM by IFA, and 291 ± 91 nM and 6,767 ± 1,827 nM by a plaque-formation assay; and 2) synergistically inhibited by their combination, again by IFA and plaque-formation assay. Collectively, these results suggest that the combination of remdesivir and cyclosporine merits further study as a possible treatment for COVID-19 complexed with a cytokine storm.

Antiviral therapy and immunotherapy of COVID-19

The pharmacological treatment of COVID-19 has evolved in the months since the description of the disease. Published observational studies and, above all, clinical trials have highlighted drugs that are useful as well as ruled out any benefit from other drugs used at the beginning of the pandemic. The pathogenesis of the disease has suggested that patients may benefit from the administration of both antivirals, mainly in the earliest stages, and anti-inflammatory/immunomodulatory medications in more advanced stages. We present a short review of the drugs used and under investigation for the treatment of COVID-19.

Early Use of Remdesivir in Patients Hospitalized With COVID-19 Improves Clinical Outcomes: A Retrospective Observational Study

BACKGROUND

Remdesivir treatment, like most antiviral drugs, is likely to be most effective when used early in the course of coronavirus disease 2019 (COVID-19). Optimal timing of remdesivir for the treatment of COVID-19 remains unclear.

OBJECTIVES

The aim of this study was to determine whether early treatment with remdesivir improves clinical outcomes: length of stay, need for mechanical ventilation, and death.

METHODS

We conducted a retrospective observational study of patients hospitalized with COVID-19 who received remdesivir therapy within 10 days of symptom onset at a large health system in Georgia, United States.

RESULTS

We identified a total of 475 patients. Initiation of therapy 3 days or less from first positive SARS-CoV-2 improved length of stay (15.7 days) compared with those started on therapy more than 3 days after a positive test (19.3 days) (P = 0.03). In the ≤3 day group, further reduction in length of stay was seen in those with lower oxygen requirement at baseline (P < 0.0001). Length of stay was lower in the ≤3 day group both with and without the use of corticosteroids (P = 0.0003). The odds of requiring mechanical ventilation were higher for the >3 day group compared with the ≤3 day group (odds ratio, 1.5; 95% confidence interval, 0.8-2.7), and the odds of death were higher for the >3 day group versus the ≤3 day group (odds ratio, 1.74; 95% confidence interval, 0.9-3.2).

CONCLUSIONS

Our data show that early treatment with remdesivir in patients hospitalized with COVID-19 shortened length of stay.

Prospect of compassionate use in China from remdesivir

Compassionate use may play an important role in responding to major public health emergencies. The Jinyintan Hospital in Wuhan launched the III phase of clinical trials of antiviral drug-remdesivir on February 6, 2020. As an unapproved drug, remdesivir raised great concerns about compassionate use in China. Compassionate use is therapeutic use of unauthorized drugs outside of clinical trials. It is used for critically ill patients with life-threatening diseases and no effective treatment means in China. Patients voluntarily apply to their medical institutions. The Center for Drug Evaluation, National Medical Products Administration shall conduct scientific and reasonable review, approval, and supervision on patients' application for compassionate medication. By analyzing and comparing the current situation of compassionate use at home and abroad, it is expected to provide thinking for the development of compassionate use system in China.

Experience of Treating COVID-19 With Remdesivir and Convalescent Plasma in a Resource-Limited Setting: A Prospective, Observational Study

Background

Convalescent plasma therapy (CPT) and remdesivir (REM) have been approved for investigational use to treat coronavirus disease 2019 (COVID-19) in Nepal.

Methods

In this prospective, multicentered study, we evaluated the safety and outcomes of treatment with CPT and/or REM in 1315 hospitalized COVID-19 patients over 18 years in 31 hospitals across Nepal. REM was administered to patients with moderate, severe, or life-threatening infection. CPT was administered to patients with severe to life-threatening infections who were at high risk for progression or clinical worsening despite REM. Clinical findings and outcomes were recorded until discharge or death.

Results

Patients were classified as having moderate (24.2%), severe (64%), or life-threatening (11.7%) COVID-19 infection. The majority of CPT and CPT + REM recipients had severe to life-threatening infections (CPT 98.3%; CPT + REM 92.1%) and were admitted to the intensive care unit (ICU; CPT 91.8%; CPT + REM 94.6%) compared with those who received REM alone (73.3% and 57.5%, respectively). Of 1083 patients with reported outcomes, 78.4% were discharged and 21.6% died. The discharge rate was 84% for REM (n = 910), 39% for CPT (n = 59), and 54.4% for CPT + REM (n = 114) recipients. In a logistic model comparing death vs discharge and adjusted for age, gender, steroid use, and severity, the predicted margin for discharge was higher for recipients of remdesivir alone (0.82; 95% CI, 0.79–0.84) compared with CPT (0.58; 95% CI, 0.47–0.70) and CPT + REM (0.67; 95% CI, 0.60–0.74) recipients. Adverse events of remdesivir and CPT were reported in <5% of patients.

Conclusions

This study demonstrates a safe rollout of CPT and REM in a resource-limited setting. Remdesivir recipients had less severe infection and better outcomes.

ClinicalTrials.gov identifier. NCT04570982.

Viral Load Kinetics of Severe Acute Respiratory Syndrome Coronavirus 2 in Hospitalized Individuals With Coronavirus Disease 2019

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) kinetics remain understudied, including the impact of remdesivir. In hospitalized individuals, peak sputum viral load occurred in week 2 of symptoms, whereas viremia peaked within 1 week of symptom-onset, suggesting early systemic seeding of SARS-CoV-2. Remdesivir treatment was associated with faster viral decay.

Efficacy of Remdesivir-Containing Therapy in Hospitalized COVID-19 Patients: A Prospective Clinical Experience

Objectives: Remdesivir is currently approved for the treatment of COVID-19. The recommendation for using remdesivir in patients with COVID-19 was based on the in vitro and in vivo activity of this drug against SARS-CoV-2. Methods: This was a prospective observational study conducted on a population of patients hospitalized for COVID-19. The primary endpoint of this study was the impact of remdesivir-containing therapy on 30-day mortality; the secondary endpoint was the impact of remdesivir-containing therapy on the need for high-flow oxygen therapy (HFNC), non-invasive ventilation (NIV), or mechanical ventilation. The data were analyzed after propensity score matching. Results: A total of 407 patients with SARS-CoV-2 pneumonia were consecutively enrolled. Out of these, 294 (72.2%) were treated with remdesivir and 113 (27.8%) were not. Overall, 61 patients (14.9%) were treated during hospitalization with HFNC, NIV, or mechanical ventilation, while 30-day mortality was observed in 21 patients (5.2%). Univariate analysis of patients treated with remdesivir or not showed no differences in 30-day mortality (4% vs. 6%, p = 0.411) in the two study groups. Cox regression analysis, after propensity score matching, showed that therapies, including remdesivir-containing therapy, were not statistically associated with 30-day survival or mortality. The Kaplan–Meier curves of 30-day survival in patients treated with remdesivir or not before (p = 0.24) and after (p = 0.88) propensity score matching showed no differences between the two study groups. Finally, patients treated with remdesivir or not showed the same need for HFNC/NIV or mechanical ventilation. Conclusions: This real-life experience of remdesivir use in hospitalized patients with COVID-19 was not associated with significant increases in rates of survival or reduced use of HFNC/NIV or mechanical ventilation compared with patients treated with other therapies not including remdesivir.

Optimal timing of remdesivir initiation in hospitalized COVID-19 patients administered with dexamethasone

BACKGROUND

Evidence is lacking about any additional benefits of introducing remdesivir on top of dexamethasone, and the optimal timing of initiation.

METHODS

In a territory-wide cohort of 10,445 COVID-19 patients from Hong Kong who were hospitalized between 21st January 2020 and 31st January 2021, 1544 patients had received dexamethasone during hospitalization. Exposure group consisted of patients who had initiated remdesivir prior to dexamethasone (n=93), or co-initiated the two drugs simultaneously (n=373); whereas non-exposure group included patients who were given remdesivir after dexamethasone (n=149), or those without remdesivir use (n=929). Multiple imputation and inverse probability of treatment weighting for propensity score were applied and hazard ratios (HR) of event outcomes were estimated using Cox regression models.

RESULTS

Time to clinical improvement (HR=1.23, 95%CI 1.02-1.49, p=0.032) and positive IgG antibody (HR=1.22, 95%CI 1.02-1.46, p=0.029) were significantly shorter in the exposure group than that of non-exposure. The exposure group had a shorter hospital length of stay by 2.65 days among survivors, lower WHO clinical progression scale scores from five days of follow-up onwards, lower risks of in-hospital death (HR=0.59, 95%CI 0.36-0.98, p=0.042) and composite outcomes; and without experiencing an increased risk of ARDS. Differences in the cumulative direct medical costs between groups were no longer significant from 17 days of follow-up onwards.

CONCLUSIONS

Initiation of remdesivir prior to or simultaneously with dexamethasone was associated with significantly shorter time to clinical improvement and positive IgG antibody, lower risk of in-hospital death, in addition to shorter length of hospital stay in patients with moderate COVID-19.

Molecular Dynamics Simulations Reveal the Interaction Fingerprint of Remdesivir Triphosphate Pivotal in Allosteric Regulation of SARS-CoV-2 RdRp

The COVID-19 pandemic has now strengthened its hold on human health and coronavirus' lethal existence does not seem to be going away soon. In this regard, the optimization of reported information for understanding the mechanistic insights that facilitate the discovery towards new therapeutics is an unmet need. Remdesivir (RDV) is established to inhibit RNA-dependent RNA polymerase (RdRp) in distinct viral families including Ebola and SARS-CoV-2. Therefore, its derivatives have the potential to become a broad-spectrum antiviral agent effective against many other RNA viruses. In this study, we performed comparative analysis of RDV, RMP (RDV monophosphate), and RTP (RDV triphosphate) to undermine the inhibition mechanism caused by RTP as it is a metabolically active form of RDV. The MD results indicated that RTP rearranges itself from its initial RMP-pose at the catalytic site towards NTP entry site, however, RMP stays at the catalytic site. The thermodynamic profiling and free-energy analysis revealed that a stable pose of RTP at NTP entrance site seems critical to modulate the inhibition as its binding strength improved more than its initial RMP-pose obtained from docking at the catalytic site. We found that RTP not only occupies the residues K545, R553, and R555, essential to escorting NTP towards the catalytic site, but also interacts with other residues D618, P620, K621, R624, K798, and R836 that contribute significantly to its stability. From the interaction fingerprinting it is revealed that the RTP interact with basic and conserved residues that are detrimental for the RdRp activity, therefore it possibly perturbed the catalytic site and blocked the NTP entrance site considerably. Overall, we are highlighting the RTP binding pose and key residues that render the SARS-CoV-2 RdRp inactive, paving crucial insights towards the discovery of potent inhibitors.

Model-Informed Repurposing of Medicines for SARS-CoV-2: Extrapolation of Antiviral Activity and Dose Rationale for Paediatric Patients

Repurposing of remdesivir and other drugs with potential antiviral activity has been the basis of numerous clinical trials aimed at SARS-CoV-2 infection in adults. However, expeditiously designed trials without careful consideration of dose rationale have often resulted in treatment failure and toxicity in the target patient population, which includes not only adults but also children. Here we show how paediatric regimens can be identified using pharmacokinetic-pharmacodynamic (PKPD) principles to establish the target exposure and evaluate the implications of dose selection for early and late intervention. Using in vitro data describing the antiviral activity and published pharmacokinetic data for the agents of interest, we apply a model-based approach to assess the exposure range required for adequate viral clearance and eradication. Pharmacokinetic parameter estimates were subsequently used with clinical trial simulations to characterise the probability target attainment (PTA) associated with enhanced antiviral activity in the lungs. Our analysis shows that neither remdesivir, nor anti-malarial drugs can achieve the desirable target exposure range based on a mg/kg dosing regimen, due to a limited safety margin and high concentrations needed to ensure the required PTA. To date, there has been limited focus on suitable interventions for children affected by COVID-19. Most clinical trials have defined doses selection criteria empirically, without thorough evaluation of the PTA. The current results illustrate how model-based approaches can be used for the integration of clinical and nonclinical data, providing a robust framework for assessing the probability of pharmacological success and consequently the dose rationale for antiviral drugs for the treatment of SARS-CoV-2 infection in children.

The Binding of Remdesivir to SARS-CoV-2 RNA-Dependent RNA Polymerase May Pave The Way Towards the Design of Potential Drugs for COVID-19 Treatment

AIM

We seek to provide an understanding of the binding mechanism of Remdesivir, as well as structural and conformational implications on SARS-CoV-2 virus RNA-dependent RNA polymerase upon its binding and identify its crucial pharmacophoric moieties.

BACKGROUND

The coronavirus disease of 2019 (COVID-19) pandemic had infected over a million people, with 65,000 deaths as of the first quarter of 2020. The current limitation of effective treatment options with no approved vaccine or targeted therapeutics for the treatment of COVID-19 has posed serious global health threats. This has necessitated several drug and vaccine development efforts across the globe. To date, the farthest in the drug development pipeline is Remdesivir.

OBJECTIVES

We performed the molecular dynamics simulation, quantified the energy contributions of binding site residues using per-residue energy decomposition calculations, and subsequently generated a pharmacophore model for the identification of potential SARS-CoV-2 virus RNA-dependent RNA polymerase inhibitors.

METHODS

Integrative molecular dynamics simulations and thermodynamic calculations coupled with advanced post-molecular dynamics analysis techniques were employed.

RESULTS

Our analysis showed that the modulatory activity of Remdesivir is characterized by an extensive array of high-affinity and consistent molecular interactions with specific active site residues that anchor Remdemsivir within the binding pocket for efficient binding. These residues are ASP452, THR456, ARG555, THR556, VAL557, ARG624, THR680, SER681, and SER682. Results also showed that Remdesivir binding induces minimal individual amino acid perturbations, subtly interferes with deviations of C-α atoms, and restricts the systematic transition of SARS-CoV-2 RNA-dependent RNA polymerase from the "buried" hydrophobic region to the "surface-exposed" hydrophilic region. We also mapped a pharmacophore model based on the observed high-affinity interactions with SARSCoV- 2 virus RNA-dependent RNA polymerase, which showcased the crucial functional moieties of Remdesivir and was subsequently employed for virtual screening.

CONCLUSION

The structural insights and the provided optimized pharmacophoric model would augment the design of improved analogs of Remdesivir that could expand treatment options for COVID-19.

Pre-Hospital Administration of Remdesivir during a SARS-CoV-2 Outbreak in a Skilled Nursing Facility

Completion of a 5-day course of remdesivir was associated with approximately 17-fold increased odds of survival among a sample of 54 nursing home residents with SARS-CoV-2 infection during the course of an outbreak from October to December, 2020. Remdesivir was well-tolerated; administration was logistically feasible in a pre-hospital environment.

Key Metabolic Enzymes Involved in Remdesivir Activation in Human Lung Cells

Remdesivir (RDV; GS-5734, Veklury), the first FDA-approved antiviral to treat COVID-19, is a single-diastereomer monophosphoramidate prodrug of an adenosine analogue. RDV is taken up in the target cells and metabolized in multiple steps to form the active nucleoside triphosphate (TP) (GS-443902), which, in turn, acts as a potent and selective inhibitor of multiple viral RNA polymerases. In this report, we profiled the key enzymes involved in the RDV metabolic pathway with multiple parallel approaches: (i) bioinformatic analysis of nucleoside/nucleotide metabolic enzyme mRNA expression using public human tissue and lung single-cell bulk mRNA sequence (RNA-seq) data sets, (ii) protein and mRNA quantification of enzymes in human lung tissue and primary lung cells, (iii) biochemical studies on the catalytic rate of key enzymes, (iv) effects of specific enzyme inhibitors on the GS-443902 formation, and (v) the effects of these inhibitors on RDV antiviral activity against SARS-CoV-2 in cell culture. Our data collectively demonstrated that carboxylesterase 1 (CES1) and cathepsin A (CatA) are enzymes involved in hydrolyzing RDV to its alanine intermediate MetX, which is further hydrolyzed to the monophosphate form by histidine triad nucleotide-binding protein 1 (HINT1). The monophosphate is then consecutively phosphorylated to diphosphate and triphosphate by cellular phosphotransferases. Our data support the hypothesis that the unique properties of RDV prodrug not only allow lung-specific accumulation critical for the treatment of respiratory viral infection such as COVID-19 but also enable efficient intracellular metabolism of RDV and its MetX to monophosphate and successive phosphorylation to form the active TP in disease-relevant cells.