Azvudine is a thymus-homing anti-SARS-CoV-2 drug effective in treating COVID-19 patients

Development of Orally Bioavailable Octahydroindole-Based Peptidomimetic Derivative as a Broad-Spectrum Inhibitor against HCoV-OC43 and SARS-CoV-2

A series of novel Mpro inhibitors was designed and synthesized to combat the coronavirus, such as HCoV-OC43 and SARS-CoV-2, and several compounds showed comparable antiviral activity to nirmatrelvir. Among them, an octahydroindole-based peptidomimetic covalent inhibitor 28f showed strong inhibitory activity against Mpros and exhibited broad-spectrum anticoronavirus activity with EC50 values ranging from 0.027 to 4.41 μM. Besides, this compound displayed potent antiviral activity against EV71. Compared to FB2001, 28f displayed better pharmacokinetic properties, and the value of oral bioavailability in CD-1 mice and Beagle dogs was improved to 10.4 and 10.2%, respectively. In addition, oral treatment with 28f could significantly reduce the viral loads of HCoV-OC43 in mice, and compound 28f could also effectively reduce lung viral loads in a K18-hACE2 transgenic mouse model without ritonavir. Taken together, compound 28f is a promising orally bioavailable broad-spectrum antiviral drug candidate that deserves further research.

Effectiveness of azvudine versus nirmatrelvir/ritonavir for hospitalized patients with SARS-CoV-2 infection and pre-existing liver diseases

BACKGROUND

Azvudine and nirmatrelvir/ritonavir are recommended as priority treatments for SARS-CoV-2 infection in China, but their effectiveness and safety in patients with pre-existing chronic liver diseases remains unknown.

METHODS

We conducted a multicenter retrospective cohort study of hospitalized SARS-CoV-2 infected patients with chronic liver diseases in ten hospitals of Henan Province. Azvudine recipients were 2:1 propensity score matched with nirmatrelvir/ritonavir recipients. Efficacy and safety were evaluated by Kaplan-Meier analysis, multivariable Cox regression model, subgroup analysis, as well as sensitivity analyses.

RESULTS

Among 37606 hospitalized patients infected with SARS-CoV-2, 1355 azvudine recipients and 373 nirmatrelvir/ritonavir recipients met the inclusion criteria. Patients with azvudine treatment showed comparable effectiveness to nirmatrelvir/ritonavir with regard to both all-cause death (P = 0.34) and composite disease progression (P = 0.32), even after adjusting for other covariates (all-cause death: HR: 0.80, 95%CI: 0.574-1.128; composite disease progression: HR: 1.31, 95%CI: 0.999-1.723). Notably, compared with nirmatrelvir/ritonavir, azvudine showed better effectiveness for patients with a comorbidity of primary malignant tumor in reducing all-cause death. Four sensitivity analyses further confirmed the robustness.

CONCLUSIONS

The effectiveness of azvudine may potentially comparable to nirmatrelvir/ritonavir in SARS-CoV-2 infected patients with pre-existing liver diseases with respect to all-cause death and composite disease progression, without serious safety concerns. Due to the existence of potential biases, further studies still need to evaluate the efficacy of these two drugs.

TRIAL REGISTRATION

The trial was retrospectively registered at ClinicalTrials.gov (CT.gov identifier: NCT06349655).

Advances in the effectiveness and safety of azvudine treatment: a comprehensive review

The global impact of COVID-19 has highlighted the urgent need for effective therapeutic interventions against SARS-CoV-2. Azvudine, a dual-target nucleoside drug initially developed for human immunodeficiency virus (HIV), has gained attention for its potential in treating COVID-19. On 25 July 2022, Azvudine received conditional approval from the National Medical Products Administration (NMPA) of China, making it the first oral SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) inhibitor for COVID-19 treatment. This review explores the pharmacological activity, antiviral mechanisms, and clinical effectiveness of azvudine in the context of COVID-19. Clinical trials have demonstrated its ability to reduce the viral load, shorten the time to nucleic acid negativity, and improve clinical outcomes in patients. Additionally, azvudine has shown excellent pharmacokinetic properties and a favorable safety profile with mild side effects. The review also addresses the importance of drug interactions and safety considerations, particularly in high-risk populations. Research should focus on optimizing second-generation inhibitors with enhanced effectiveness against SARS-CoV-2 variants, improving oral bioavailability, and minimizing adverse effects, ensuring more robust treatment options for COVID-19.

Composite outcome of oral azvudine vs. nirmatrelvir-ritonavir in COVID-19 patients: a retrospective cohort study

Objective

To explore the effectiveness and safety of azvudine and nirmatrelvir-ritonavir in a real-world setting.

Methods

This retrospective cohort study included adult patients with confirmed COVID-19 who received azvudine or nirmatrelvir-ritonavir treatment at Shanghai Changhai Hospital between 1 November 2022, and 30 March 2023. Data were collected from the hospital's electronic medical record system using a standardized data extraction form. Propensity score matching (PSM) was used to control for potential confounding factors. The primary outcome was the incidence of composite disease progression, defined as the occurrence of death, ICU admission, invasive respiratory support, or high-flow oxygen therapy. Multivariable Cox regression analysis was performed to identify the factors independently associated with the composite progression outcomes.

Results

This study included 476 patients: 296 treated with azvudine and 180 treated with nirmatrelvir-ritonavir. After PSM, 139 patients were included in each group. There were no statistically significant differences between the two groups regarding the composite outcome (log-rank: P = 0.475; HR: 0.82, 95%CI: 0.46-1.43, P = 0.478), death (log-rank: P = 0.526; HR: 0.82, 95%CI: 0.44-1.52, P = 0.528), ICU admission (log-rank: P = 0.525; HR: 0.69, 95%CI: 0.22-2.18, P = 0.526), invasive ventilation (log-rank: P = 0.814; HR: 1.20, 95%CI: 0.27-5.39, P = 0.814), or oxygen use (log-rank: P = 0.370; HR: 1.44, 95%CI: 0.65-3.18, P = 0.372). The multivariable analysis showed that the antiviral drug (HR = 0.861, 95%CI: 0.486-1.524, P = 0.607) was not independently associated with the composite outcome. Only severe COVID-19 was independently associated with the composite outcome (HR = 3.322, 95%CI: 1.569-7.031, P = 0.002). The safety outcomes were similar between the two groups.

Conclusion

This real-world study demonstrates comparable efficacy and safety profiles between azvudine and nirmatrelvir-ritonavir in treating COVID-19 patients, regardless of disease severity or baseline characteristics. The findings support azvudine as a practical alternative for treatment selection, particularly in resource-constrained settings or for patients with contraindications to specific therapies. Clinical decisions should prioritize patient-specific needs, accessibility, and cost-effectiveness. Further large-scale prospective studies are needed to validate these observations and refine subgroup-specific treatment strategies.

Potent antiviral activity of simnotrelvir against key epidemic SARS-CoV-2 variants with a high resistance barrier

Simnotrelvir is an oral small-molecule antiviral agent targeting the 3C-like protease (3CLpro) of SARS-CoV-2, proven effective against the Delta variant with favorable pharmacokinetics and safety in preclinical study. In this study, we further evaluated the antiviral efficacy of simnotrelvir against a range of emerging Omicron variants, including BA.1, BA.4, BA.5, CH.1.1, XBB.1.5, XBB.1.16, EG.5, and JN.1. In vitro assays with Vero E6 cells confirmed that simnotrelvir exhibited robust antiviral activity across these variants, comparable to the Food and Drug Administration (FDA)-approved drug nirmatrelvir. Additionally, simnotrelvir demonstrated effective inhibition against several nirmatrelvir-resistant SARS-CoV-2 3CLpro mutants, including A260V, Y54A, (T21I + S144A), F140A, H172Y, and E166V. Importantly, simnotrelvir showed better potency against the E166V mutation compared to nirmatrelvir. Resistance selection studies revealed that BA.5 developed reduced sensitivity after 5 and 10 passages, increasing the IC50 values by 3.2 and 4.5-fold, respectively, while HCoV-OC43 showed an 8.3-fold increase after 12 passages. Despite this, simnotrelvir's overall efficacy remains strong. Furthermore, clinical trials demonstrated that combining simnotrelvir with ritonavir significantly shortened symptom resolution in COVID-19 patients. Genomic analysis of treated patients found random nucleotide substitutions but no significant mutations linked to 3CLpro resistance. In conclusion, simnotrelvir shows strong antiviral activity against SARS-CoV-2 variants and maintains a high barrier to resistance, reinforcing its potential as an effective therapeutic option for current and future SARS-CoV-2 variants.

The Antiviral Efficacy and Safety of Azvudine in Hospitalized SARS-CoV-2 Infected Patients with Liver Diseases Based on a Multicenter, Retrospective Cohort Study

Despite azvudine being prioritized for the treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, its effectiveness and safety remain inadequately substantiated in hospitalized SARS-CoV-2 infected patients with liver diseases. A retrospective nine-center cohort study along with an independent validation cohort is conducted to examine the efficacy of azvudine (Clinical Trial Registration Number: NCT06349655). The primary outcome is all-cause mortality and the secondary outcome is composite disease progression. Efficacy is assessed via Kaplan-Meier analysis and Cox regression, with subgroup and sensitivity analyses for further validation. Among 32 864 hospitalized SARS-CoV-2 infected patients, 1022 eligible azvudine recipients, and 1022 controls are included through propensity score match. Kaplan-Meier analysis reveals that azvudine treatment is associated with a lower risk of all-cause mortality and composite disease progression (both p<0.0001). Cox regression analysis suggests azvudine recipients could have a 39% lower risk of all-cause mortality than controls (95% confidence interval [CI]: 0.468-0.795, p<0.001), but with no notable significance in composite disease progression (hazard ratio: 0.85, 95% CI: 0.686-1.061, p = 0.154). Subgroup analysis suggests that azvudine has a greater benefit for both all-cause mortality and composite disease progression in patients with kidney diseases or without autoimmune diseases. Three sensitivity analyses and validation cohorts confirm the robustness of the findings. Safety analysis observes few adverse events in azvudine recipients. Within 15 days after azvudine administration, no significant difference in liver function indexes and kidney function indexes is observed between the two groups except for a few time points. These findings demonstrate that azvudine shows potential clinical efficacy in improving all-cause mortality in hospitalized SARS-CoV-2 infected patients with liver diseases, with acceptable adverse effects.

Effectiveness and Safety of Oral Azvudine for Elderly Hospitalized Patients With COVID-19: A Multicenter, Retrospective, Real-World Study

Azvudine is recommended as a priority treatment for patients with Coronavirus Disease 2019 (COVID-19) during Omicron wave in China, but its efficacy and safety in elderly patients is unknown. In this multicenter, retrospective study, we identified 19763 elderly patients (aged over 60 years) with COVID-19 from nine hospitals in Henan Province, China. The primary outcome is all-cause death and the secondary outcome is composite disease progression. After propensity score matching, 4109 Azvudine recipients and 4109 matched controls is included, with average age of 75.15 years. Kaplan-Meier analysis reveales a notably survival and progression-free benefit in Azvudine treatment. The Cox analysis shows that compared with controls, Azvudine recipients have a 33% lower risk of all-cause death (95% confidence Interval (CI): 0.580-0.772, p < 0.001), but have no significant difference in composite disease progression (hazard ratio: 0.93, 95% CI: 0.833-1.046, p = 0.234). Subgroup analysis suggested Azvudine have a stronger protective effect in patients concomitant with antibiotics. Three sensitive analyses confirm the robustness of the findings. The safety of Azvudine in elderly patients is acceptable. These findings indicate that Azvudine therapy can reduce the rate of all-cause death in hospitalized elderly patients with COVID-19, and without obvious adverse events.

Clinical Characteristics of SARS-COV-2 Omicron Variant in Acute Myeloid Leukemia and Acute Lymphocytic Leukemia Patients: A Multi-Center Retrospective Study

BACKGROUND

The death rate of hematological malignancies is high, and the death rate of patients with COVID-19 infection is further increased. Although there have been expert consensus and relevant guidelines to introduce the recommendations of the guidelines for patients with hematological malignancies complicated with COVID-19 infection, there is limited understanding of the clinical characteristics of Chinese patients with acute leukemia complicated with COVID-19 infection.

AIMS

This study aimed to analyze the clinical manifestations, mortality, and determinants of viral shedding duration in Chinese AL patients infected with COVID-19.

METHODS

We conducted a retrospective study of 100 AL patients with COVID-19 infection in Henan Province, China, from December 1, 2022, to January 31, 2023. Data on demographics, leukemia subtype, symptoms, treatments (antibiotics/antivirals), and viral shedding duration were collected. Follow-up was conducted over three months to assess mortality. Univariate and multivariate analyses were performed to identify risk factors.

RESULTS

The median age was 49.5 years (58% male, 42% female), with 76% having acute myeloid leukemia (AML) and 24% acute lymphoblastic leukemia (ALL). Most patients (86%) were asymptomatic. Antibiotics and antivirals were administered to 35% and 25% of patients, respectively. Severe cases and fatalities exhibited prolonged viral shedding. Neutropenic patients on antibiotics had significantly extended shedding duration, whereas antiviral therapy or delayed primary disease management shortened it. The overall mortality rate was 6%. Univariate analysis identified neutropenia as a key mortality risk factor, though multivariate analysis showed no significant associations.

CONCLUSION

Early antiviral treatment may reduce viral shedding duration and potentially mitigate symptom severity and mortality in AL patients with COVID-19. Neutropenia emerged as a critical factor influencing outcomes. These findings underscore the importance of tailored therapeutic strategies for this high-risk population.

Antiviral effectiveness and safety of azvudine in hospitalized SARS‐CoV‐2 patients with pre‐existing chronic respiratory diseases: A multicenter, retrospective cohort study

Although azvudine has become a priority in the treatment of SARS‐CoV‐2, its effectiveness and safety among COVID‐19 patients who already have chronic respiratory diseases (CRDs) have not been sufficiently validated. A retrospective, multicenter cohort study involving 10 hospitals in Henan Province was performed to assess inpatients with COVID‐19 and CRDs (Clinical Trial Registration Number: NCT06349655). Azvudine recipients and the control group were matched at a 1:1 ratio using propensity scores. The clinical outcomes (all‐cause death and composite disease progression) were analyzed using Kaplan‒Meier and Cox regression analyses, with additional subgroup and sensitivity analyses performed. Eighteen clinical features were included to construct a nomogram for predicting the survival of inpatients with COVID‐19 and CRDs. Out of 37,606 hospitalized COVID‐19 patients, 1462 azvudine recipients and 1462 matched controls were included in the analysis. The results of Kaplan‒Meier and multivariate Cox regression analyses demonstrated that in contrast to the controls, azvudine use was associated with a decreased risk of all‐cause death in patients with COVID‐19 and pre‐existing CRDs (log‐rank: p = .012; HR: 0.73; 95% CI: 0.553‒0.956); but was not significantly different in terms of composite disease progression (log‐rank: p = .82; HR: 1.15; 95% CI: 0.948‒1.383). An analysis of subgroups and three sensitivity appraisals validate the above outcomes. The number and type of adverse events associated with azvudine treatment were acceptable. The concordance index (0.8499, 0.8497) and area under the curve (86.1%, 80.4%) of the nomogram showed satisfactory discriminative ability in the training and test sets. Azvudine could be effective in reducing all‐cause death among inpatients with COVID‐19 and CRDs and had few serious adverse events.

Efficacy and safety of azvudine versus nirmatrelvir/ritonavir in cancer patients with COVID-19

Cancer significantly contributes to the unfavorable prognosis of coronavirus disease 2019 (COVID-19) patients. The efficacy and safety of azvudine and nirmatrelvir/ritonavir (Paxlovid) in cancer patients with COVID-19 remain uncertain. Therefore, we designed a comprehensive retrospective study encompassing clinical data of 32,864 hospitalized COVID-19 patients, 691 of whom were cancer patients treated with azvudine and 200 were cancer patients treated with Paxlovid. After 2:1 propensity score matching, 397 patients in the azvudine group and 199 patients in the Paxlovid group were enrolled. Cox regression analysis revealed the risk of all-cause death (HR: 1.84, 95% CI: 1.059-3.182, P = 0.030) and composite disease progression (HR: 1.70, 95% CI: 1.043-2.757, P = 0.033) were greater in the Paxlovid group than in the azvudine group. Two sensitivity analyses confirmed the robustness of our findings. The safety analysis of adverse events revealed no statistically significant differences between the two groups. In conclusion, we carried out the first analysis to compare the efficacy and safety of azvudine and Paxlovid in cancer patients with COVID-19 and demonstrated that azvudine significantly reduced the risk of all-cause death and composite disease progression among cancer patients with COVID-19 compared with Paxlovid.

Mechanism and Efficacy of Etanercept in Treating Autoimmune-like Manifestations of Coronavirus Disease 2019 in elderly individuals

During the COVID-19 pandemic, extensive research focused on universal treatments, but few studies addressed treatment regimens for elderly patients. This study aimed to evaluate the effects of etanercept, a TNF inhibitor, in elderly individuals with COVID-19 through observational analysis of compassionate use cases. The results showed that after one month of etanercept treatment, clinical indicators such as C-reactive protein, D-dimer, and fibrinogen normalised, whereas the control group receiving conventional treatment did not fully recover. Single-cell sequencing was performed on seven patients treated with etanercept and two uninfected individuals. Based on our data and in conjunction with external data, a comprehensive characterization map involving 400,000 cells was created. Transcriptomic analysis revealed autoimmune-like manifestations in elderly patients, highlighting the importance of immunotherapy. Plasma cells, platelets, and B cells were the most treatment-sensitive cells. Analysis of five drug types, including antiviral, etanercept, glucocorticoids, tocilizumab, and others, showed that tocilizumab was associated with an increased thrombosis risk in elderly patients. Meanwhile, etanercept alleviated autoimmune-like manifestations by inhibiting platelet factor 4 and suppressing TNF-α. Molecular docking showed etanercept's strong affinity (-15.0 kcal/mol) for the spike protein of the SARS-CoV-2 Omicron variant, suggesting it may protect immune-compromised patients. Our findings support etanercept as a potential treatment for elderly COVID-19 patients with autoimmune-like manifestations.

Development and validation of a nomogram to assess the occurrence of liver dysfunction in patients with COVID-19 pneumonia in the ICU

The global pandemic of novel coronavirus pneumonia (COVID-19) has resulted in millions of deaths over the past three years. As one of the most commonly affected extra-pulmonary organs, numerous studies have reported varying degrees of liver injury in a significant proportion of patients with COVID-19, particularly in severe and critically ill patients. Early prediction of liver dysfunction in hospitalized patients would facilitate the clinical management of COVID-19 and improve clinical prognosis, but reliable and valid predictive models are still lacking.MethodsWe collected data from 286 patients with RT-PCR confirmed COVID-19 admitted to various ICUs from the case system. These patients were randomly divided into a training cohort (50%) and a validation cohort (50%). In the training cohort, we first used ROC curves to measure the predictive efficiency of each of the variables for the development of liver damage during hospitalization in patients with COVID-19, followed by LASSO regression analysis to screen the variables for predictive models and logistic regression analysis to identify relevant risk factors. A nomogram based on these variables was created following the above model. Finally, the efficiency of the prediction models in the training and validation cohorts was assessed using AUC, consistency index (C index), calibration curves and Decision Curve Analysis.ResultsOut of a total of 80 parameters for COVID-19 patients admitted to the ICUs, 10 were determined to be significantly associated with the occurrence of liver dysfunction during hospitalization. Based on these predictors, further prediction models were used to construct and develop a nomogram that was offered for practical clinical application. The C-index of the column line graphs for the training and validation cohorts was 0.956 and 0.844 respectively. in addition, the calibration curves for the model showed a high degree of agreement between the predicted and actual incidence of liver dysfunction in patients with COVID-19.ConclusionBy developing a predictive model and associated nomogram, we predicted the incidence of liver dysfunction during hospitalization in patients with COVID-19 in the ICU. The model's predictive performance was determined in both the training and validation cohorts, contributing to the clinical management of COVID-19.

Mycophenolate mofetil exerts broad-spectrum antiviral activity against coronaviruses including SARS-CoV-2

BACKGROUND

New anti-coronavirus drugs are continuously being developed to address the serious long-term challenge posed by numerous SARS-CoV-2 variants. The clinical immunosuppressants mycophenolate mofetil (MMF) and mycophenolic acid (MPA) have been reported to have anti-coronavirus activities. However, systematic studies have not been conducted to evaluate their activities and mechanisms against pan-coronaviruses, including SARS-CoV-2.

METHODS

The antiviral effect of MMF and MPA was determined by qRT-PCR assay, Western blotting, and immunofluorescence assay. The IMPDH inhibition effect of MMF was determined by cellular thermal shift assay and Western blotting.

RESULTS

We showed that MMF and MPA had broad-spectrum inhibitory effect against coronavirus, including HCoV-229E, HCoV-OC43, and SARS-CoV-2 ancestral strain and its variants. In terms of characteristics, MMF acted in the early stages of viral infection and inhibited viral replication by blocking purine nucleotide synthesis through interaction with inosine-5'-monophosphate dehydrogenase (IMPDH). Therefore, the antiviral effect of MMF can be reversed by exogenous guanosine. Additionally, MMF in combination with molnupiravir, GC376 or E64d showed synergistic antiviral effects.

CONCLUSION

MMF and MPA exerted broad-spectrum anti-coronavirus effects by inhibiting IMPDH activity. MMF had a synergistic antiviral effect when combined with other drugs, showing its potential clinical antiviral applications.

A retrospective cohort study of the efficacy and safety of oral azvudine versus nirmatrelvir/ritonavir in elderly hospitalized COVID-19 patients aged over 60 years

Azvudine and nirmatrelvir/ritonavir (Paxlovid) are recommended for COVID-19 treatment in China, but their safety and efficacy in the elderly population are not fully known. In this multicenter, retrospective, cohort study, we identified 5131 elderly hospitalized COVID-19 patients from 32,864 COVID-19 patients admitted to nine hospitals in Henan Province, China, from December 5, 2022, to January 31, 2023. The primary outcome was all-cause death, and the secondary outcome was composite disease progression. Propensity score matching (PSM) was performed to control for confounding factors, including demographics, vaccination status, comorbidities, and laboratory tests. After 2:1 PSM, 1786 elderly patients receiving azvudine and 893 elderly patients receiving Paxlovid were included. Kaplan-Meier and Cox regression analyses revealed that compared with Paxlovid group, azvudine could significantly reduce the risk of all-cause death (log-rank P = 0.002; HR: 0.71, 95% CI: 0.573-0.883, P = 0.002), but there was no difference in composite disease progression (log-rank P = 0.52; HR: 1.05, 95% CI: 0.877-1.260, P = 0.588). Four sensitivity analyses verified the robustness of above results. Subgroup analysis suggested that a greater benefit of azvudine over Paxlovid was observed in elderly patients with primary malignant tumors (P for interaction = 0.005, HR: 0.32, 95% CI: 0.18-0.57) compared to patients without primary malignant tumors. Safety analysis revealed that azvudine treatment had a lower incidence of adverse events and higher lymphocyte levels than Paxlovid treatment. In conclusion, azvudine treatment is not inferior to Paxlovid treatment in terms of all-cause death, composite disease progression and adverse events in elderly hospitalized COVID-19 patients.

Real-world effectiveness and safety of oral Azvudine versus Paxlovid for COVID-19 in patients with kidney disease: a multicenter, retrospective, cohort study

BACKGROUND

Patients with kidney disease (KD) are at high risk of contracting COVID-19 and developing severe disease. There is still a lack of guidance regarding the treatment of COVID-19 in patients with KD. The safety and effectiveness of Azvudine in treating COVID-19 patients with KD remain unknown.

METHODS

This study included 32,864 COVID-19 patients from nine centers in Henan Province, China. After applying the exclusion criteria and 2:1 propensity score matching, 438 and 219 participants in the Azvudine and Paxlovid groups, respectively, were subjected to analysis.

RESULTS

Kaplan-Meier analysis revealed no significant differences in all-cause death or composite disease progression between the Azvudine and Paxlovid groups (all p values > 0.05). The same results were obtained in the Cox regression analysis after baseline characteristics adjustment. Three different sensitivity analyses contributed to the robustness of these findings. Subgroup analysis revealed that patients treated with Azvudine had a lower risk of composite disease progression than patients treated with Paxlovid did among patients with moderate disease (p = 0.016, HR: 0.51, 95% CI: 0.27-0.96). Safety data indicated that there was no difference in the incidence of most adverse events. Compared with the Paxlovid group, the Azvudine group had a lower incidence of hypophosphatemia (p = 0.008) and a lower PLT count (p = 0.045). Moreover, during the 15-day follow-up since drug administration, higher concentrations of lymphocytes were detected in the Azvudine group.

CONCLUSIONS

This study is the first to report that the safety and effectiveness of Azvudine are not inferior to those of Paxlovid in COVID-19 patients with KD. This study provides additional treatment options for COVID-19 patients with KD.

Real-world effectiveness of azvudine versus nirmatrelvir-ritonavir in hospitalized patients with COVID-19 and pre-existing diabetes

Azvudine and nirmatrelvir-ritonavir are prioritized treatments for SARS-CoV-2 infection in China, but their effectiveness and safety in hospitalized patients with COVID-19 and pre-existing diabetes remains unknown. In this retrospective cohort study, we collected 32,864 hospitalized COVID-19 patients from nine hospitals, among which 636 azvudine recipients and 318 nirmatrelvir-ritonavir recipients were enrolled for final analysis after exclusion and propensity score matching. Kaplan-Meier and multivariate Cox regression analysis results showed that azvudine had a lower risk of all-cause death compared with nirmatrelvir-ritonavir for the treatment of patients with COVID-19 and pre-existing diabetes (log rank: p = 0.044; HR: 0.63; 95% CI: 0.431-0.934). No significant difference was found in composite disease progression between the two groups. Five sensitivity analyses verified the robustness of the results. Overall, azvudine may be comparable to nirmatrelvir-ritonavir in terms of both all-cause death and composite disease progression among hospitalized patients with COVID-19 and pre-existing diabetes, with acceptable adverse events.

A multicenter, real-world cohort study: effectiveness and safety of Azvudine in hospitalized COVID-19 patients with pre-existing diabetes

Introduction

During the Omicron infection wave, diabetic patients are susceptible to COVID-19, which is linked to a poor prognosis. However, research on the real-world effectiveness and safety of Azvudine, a common medication for COVID-19, is insufficient in those with pre-existing diabetes.

Methods

In this retrospective study, we included 32,864 hospitalized COVID-19 patients from 9 hospitals in Henan Province. Diabetic patients were screened and divided into the Azvudine group and the control group, via 1:1 propensity score matching. The primary outcome was all-cause mortality, and the secondary outcome was composite disease progression. Laboratory abnormal results were used for safety evaluation.

Results

A total of 1,417 patients receiving Azvudine and 1,417 patients receiving standard treatment were ultimately included. Kaplan-Meier curves suggested that all-cause mortality (P = 0.0026) was significantly lower in the Azvudine group than in the control group, but composite disease progression did not significantly differ (P = 0.1). Cox regression models revealed Azvudine treatment could reduce 26% risk of all-cause mortality (95% CI: 0.583-0.942, P = 0.015) versus controls, and not reduce the risk of composite disease progression (HR: 0.91, 95% CI: 0.750-1.109, P = 0.355). The results of subgroup analysis and three sensitivity analyses were consistent with the previous findings. Safety analysis revealed that the incidence rates of most adverse events were similar between the two groups.

Conclusion

In this study, Azvudine demonstrated good efficacy in COVID-19 patients with diabetes, with a lower all-cause mortality rate. Additionally, the safety was favorable. This study may provide a new strategy for the antiviral management of COVID-19 patients with diabetes.

Radical Strategy Towards N-glycosides: Current Advances and Future Prospects

N-glycosides exhibit diverse biological and pharmacological activities, making their efficient synthesis crucial for both biological research and drug development. Traditional acid-promoted N-glycosylation methods, which rely on the formation of oxocarbenium intermediates, often face significant challenges. These methods are water-sensitive and typically require neighboring group participation to achieve high selectivity. Furthermore, they depend on acid activation, rendering them incompatible with alkyl amine. Additionally, low-nucleophilicity amides often need to be converted into their TMS-derivatives to enhance reactivity, limiting the direct use of such substrates. In contrast, radical-based strategies have emerged as a promising alternative, addressing many of these limitations and leading to notable advances in N-glycosylation. This review explores the unique properties of N-glycosides, the inherent challenges of traditional N-glycosylation techniques, and the transformative advantages offered by radical-based approaches. Specifically, it highlights recent advancements in radical-mediated N-glycosylation, including photoredox radical strategies, radical/ionic hybrid approaches, and metallaphotoredox catalysis, accompanied by a detailed discussion of the underlying mechanisms. Finally, the ongoing challenges and potential future directions of N-glycoside synthesis using radical strategies are presented.

The Role of Ursodeoxycholic Acid Administration During the COVID-19 Pandemic: A Questionnaire Survey

In December 2022, China classified COVID-19 as a category B infectious disease. This ended 2 years of close epidemiological surveillance of COVID-19. The objective of this questionnaire was to assess the infection status in the COVID-19 pandemic since December in Henan Province, China, and the prevalence of infection in people who were taking ursodeoxycholic acid (UDCA) during this period. We distributed questionnaires to patients attending the gastroenterology clinic at the First Affiliated Hospital of Henan University of Chinese Medicine. The questionnaire lasted for 3 weeks and a total of 660 were collected, of which the number of people taking UDCA was 70. This is the first investigation into the rate of infection among those taking UDCA during the time of the COVID-19 pandemic. Our results showed that the overall infection rate among those taking UDCA was 71.43% (n = 50), with a 10% (n = 7) rate of asymptomatic infections, which was significantly lower than the 85.42% (n = 504) and 6.27% (n = 37) rates among respondents who did not take. The administration of UDCA showed a trend toward reducing the rate of COVID-19 infection, but the difference was not statistically significant when compared to patients with shorter durations of medication use. While less than 30% of participants remained uninfected during the study period, indicating a potential protective effect, it is important to note that complete prevention of SARS-CoV-2 infection by UDCA was not observed.

Azvudine efficacy in reducing mortality in COVID-19 patients

BACKGROUND

Several therapeutic drugs have been authorized for the treatment of patients with Coronavirus disease 2019 (COVID-19). However, further research on the mechanisms of action, efficacy, and target populations of these novel therapeutic drugs are necessary. This study included mild, moderate, severe, and critical COVID-19 patients to evaluate azvudine's effectiveness across different severity levels.

METHODS

We conducted a retrospective cohort study of patients with COVID-19 admitted to our hospital from December 1, 2022, to March 31, 2023. Patients were divided into retrospective cohorts receiving azvudine antiviral therapy and standard treatment, and were followed-up for up to 28 days.

RESULTS

Prior to data processing, azvudine treatment was associated with reduced mortality rates at 7 days (1.09/1000 persons vs. 5.06/1000 persons, P < 0.001) and 14 days (3.35/1000 persons vs. 5.65/1000 persons, P = 0.001). After propensity score matching, a decrease in mortality rates at 7 days (0.8/1000 persons vs. 6.29/1000 persons, P < 0.001), 14 days (3.42/1000 persons vs. 7.26/1000 persons, P < 0.001), and 28 days (4.33/1000 persons vs. 7.29/1000 persons, P = 0.003) were observed following azvudine treatment. After inverse probability of treatment weighting adjustment, the results were consistent with propensity score matching. In the clinical subgroup analysis, azvudine treatment intervention significantly reduced the 7-day (2.49/1000 persons vs. 14.59/1000 persons, P = 0.001 and 11.36/1000 persons vs. 66.99/1000 persons, P < 0.001), 14-day (5.22/1000 persons vs. 17.36/1000 persons, P < 0.001 and 17.08/1000 persons vs. 51.72/1000 persons, P = 0.002), and 28-day (7.58/1000 persons vs. 16.02/1000 persons, P = 0.014 and 20.43/1000 persons vs. 46.51/1000 persons, P = 0.008) mortality rates in hospitalized patients with severe and critical COVID-19.

CONCLUSIONS

The study suggests that in hospitalized patients with COVID-19, azvudine treatment significantly reduces patient mortality rates in hospitalized COVID-19 infections, wherein the effects are more pronounced in severe and critical patients.

Identification of RdRp-NiRAN/JAK1 Dual-Target Drugs for COVID-19 Treatment

Inhibition of virus replication and inflammatory response is important for the treatment of severe COVID-19 patients. RNA-dependent RNA polymerase (RdRp) is indispensable for SARS-CoV-2 replication, and Janus kinase (JAK) 1 inhibitors exert immunosuppressive effects. RdRp/JAK1 dual-target drugs are expected to ameliorate the severity of the COVID-19 disease. The N-terminal nidovirus RdRp-associated nucleotidyltransferase (NiRAN) domain of RdRp is a pseudokinase, and it has structural similarities with JAK1. Herein, we evaluated the inhibitory effects of triphosphate forms of 31 nucleoside drugs in the DrugBank database on the NiRAN domain and JAK1 through a combination of theoretical and experimental methods. By analyzing the three properties of 31 nucleoside drugs (total hydrophobic surface area, number of hydrophobic atoms, and molecular weight), these drugs met the application rule of our developed molecular docking with conformer-dependent charges (MDCC). Based on the MDCC method combined with molecular dynamics simulations, Azvudine and Citicoline among these 31 drugs showed stronger predicted binding affinities with the NiRAN domain as well as JAK1 compared to the reference drug Remdesivir. Further experimental verification, including a thermal shift assay and homogeneous time-resolved fluorescence assay, demonstrated that Azvudine was an RdRp-NiRAN/JAK1 dual-target drug. This work provided a previously unexplored mechanism of Azvudine for COVID-19 treatment and proposed a design concept for RdRp-NiRAN/JAK1 dual-target nucleoside drugs.

Real-world effectiveness and safety of azvudine in hospitalized patients with SARS-CoV-2 infection: A multicenter, retrospective cohort study

OBJECTIVES

Azvudine has been designated as a priority treatment for patients infected with SARS-CoV-2, however, clinical evidence in hospitalized cases remains insufficient.

METHODS

We performed a multi-center, retrospective cohort study to evaluate the effectiveness and safety of azvudine in hospitalized patients with SARS-CoV-2 in China (NCT06349655). Kaplan-Meier method, Cox regression model, subgroup analysis, and seven sensitive analyses were employed.

RESULTS

A total of 32864 hospitalized patients with SARS-CoV-2 were enrolled, in which 5735 azvudine recipients and 5735 controls were selected using 1:1 propensity score matching. Based on Kaplan-Meier analysis, azvudine significantly reduced rates of all-cause death (P < 0.0001) and composite disease progression (P = 0.00019). Cox regression analysis demonstrated that hazard ratios of all-cause death and composite disease progression were 0.68 (95%CI: 0.598-0.775, P < 0.001) and 0.88 (95% CI: 0.795-0.976, P = 0.016), respectively. Subgroup analysis showed preference of azvudine for patients receiving antibiotics in reducing all-cause death and composite disease progression. Seven sensitivity analyses verified the robustness of our results. Safety analysis on adverse events showed no significant difference between both groups.

CONCLUSIONS

This study suggested that azvudine may reduce all-cause death and composite disease progression in hospitalized patients with SARS-CoV-2 infection without serious adverse events. However, the findings are susceptible to some potential biases, and further studies still need to identify the efficacy of azvudine.

Efficacy of azvudine plus dexamethasone in severe hospitalized patients with Omicron infection: a prospective multicenter study

Background

Azvudine (AZV), the first Chinese oral anti-coronavirus disease 2019 (COVID-19) drug, has shown substantial clinical benefits to viral clearance and prognosis in patients with mild and common COVID-19. However, there is no evidence in severe hospitalized COVID-19 patients.

Methods

In this multicenter study, we analyzed 209 severe hospitalized COVID-19 patients in four hospitals. All the clinical data and the 28-day composite outcomes were recorded. All of the patients were categorized into two groups according to drug: the dexamethasone (DXM) group and the azvudine plus dexamethasone (AZV+DXM) group.

Results

There were no differences in sex, age, BMI, and underlying diseases between the two groups. The ratio of the 28-day composite outcome was lower for the AZV+DXM group than that for the DXM group (16.97% vs. 31.82%, p = 0.029). The viral clearance time was shorter in the AZV+DXM group than in the DXM group (7.32 ± 2.57 vs. 8.55 ± 2.34 days, p = 0.017). The PaO2/FiO2 levels on day 5 (258.89 ± 55.22 vs. 233.12 ± 60.51, p = 0.026) and day 10 (289.48 ± 44.09 vs. 261.52 ± 37.34, p = 0.015) were higher in the AZV+DXM group than the DXM group. However, data on the hospitalization duration of the two groups were similar. Cox analysis showed the benefit of AZV+DXM in the subgroups of ≥65 years old, multiple organ dysfunction syndrome (MODS), cerebrovascular disease, C-reactive protein (CRP) ≥70mg/L, and D-dimer ≥1 µg/L.

Conclusion

This study is the first to indicate that treatment with AZV+DXM might benefit severe Omicron-infected patients compared with DXM treatment alone. This finding demonstrates, at least partly, the necessity of antiviral treatment in severe patients.

Systematic evaluation of therapeutic effectiveness of Azvudine in treating COVID-19 hospitalized patients: a retrospective cohort study

Background

Azvudine, a repurposed oral small molecule antiviral drug, has potential effects in combating the SARS-CoV-2 virus. However, studies on its clinical efficacy in patients with COVID-19 are still limited and controversial, and further research and validation are necessary.

Methods

A retrospective cohort study was conducted on COVID-19 patients who were hospitalized in the General Hospital of Central Theater Command from 1 December 2022 to 31 January 2023. We included 132 patients treated with Azvudine and 132 controls after screening and propensity score matching. The primary outcomes including all-cause mortality and a composite outcome of disease progression such as non-invasive respiratory support, invasive respiratory support, admission to intensive care unit (ICU), and death were compared.

Results

Azvudine recipients had a much lower incidence rate of composite disease progression outcome than controls (13.9075/1000 person-days versus 25.7731/1000 person-days, P<0.05). Azvudine recipients also possessed a lower all-cause mortality rate than controls (2.6797/1000 person-days versus 8.5910/1000 person-days, P<0.01). Azvudine treatment significantly reduced the risk of composite disease progression (HR: 0.37, 95% CI: 0.16-0.84, P=0.017) and all-cause death (HR: 0.25, 95% CI: 0.08-0.81, P=0.021) after adjusting potential confounding factors such as age, sex, severity of COVID-19, complications, concomitant therapy, time from symptoms to treatment, and important laboratory indicators. The subgroup analyses of composite disease progression outcome and all-cause death indicated robustness of Azvudine's in treating COVID-19 patients in general.

Conclusion

Our study demonstrates that Azvudine has a significant positive impact on the clinical recovery of hospitalized patients with COVID-19. These findings provide important support for the use of Azvudine as a therapeutic option for COVID-19, given the current divergent views on its therapeutic efficacy and its importance in public health and medical care.

Human E3 ubiquitin ligases: accelerators and brakes for SARS-CoV-2 infection

E3 ubiquitin ligases regulate the composition of the proteome. These enzymes mono- or poly-ubiquitinate their substrates, directly altering protein function or targeting proteins for degradation by the proteasome. In this review, we discuss the opposing roles of human E3 ligases as effectors and targets in the evolutionary battle between host and pathogen, specifically in the context of SARS-CoV-2 infection. Through complex effects on transcription, translation, and protein trafficking, human E3 ligases can either attenuate SARS-CoV-2 infection or become vulnerabilities that are exploited by the virus to suppress the host's antiviral defenses. For example, the human E3 ligase RNF185 regulates the stability of SARS-CoV-2 envelope protein through the ubiquitin-proteasome pathway, and depletion of RNF185 significantly increases SARS-CoV-2 viral titer (iScience (2023) 26, 106601). We highlight recent advances that identify functions for numerous human E3 ligases in the SARS-CoV-2 life cycle and we assess their potential as novel antiviral agents.

Perioperative cardiovascular risk and preventions of patients with post-COVID-19 condition

COVID-19 infectious is still a widely prevalent disease today. Although most patients with COVID-19 infection are mild. Some patients still develop to post-COVID-19 conditions, significantly increasing the perioperative cardiovascular risks. To better assess and prevent the perioperative cardiovascular risks of patients with COVID-19 infection, the safety and effectiveness of clinical practice can be improved through comprehensive measures, such as medical history collection, detection of symptoms and signs, application of auxiliary examinations, selection of scales and related rehabilitation treatment.

Effectiveness and safety of azvudine versus nirmatrelvir-ritonavir in adult patients infected with COVID-19 omicron strains: a retrospective study in Beijing

The study was to evaluate the clinical outcomes of azvudine versus nirmatrelvir-ritonavir against omicron strains of coronavirus disease 2019 infections and determine their comparative effectiveness. This retrospective study included 716 patients who received nirmatrelvir-ritonavir (NR group) or azvudine (FNC group) at Peking Union Medical College Hospital between 1 November 2022 and 27 February 2023. Patients in the FNC group (n = 304) were younger, exhibited less severe symptoms, started antiviral therapy later, received corticosteroids more frequently, and used tocilizumab less frequently than patients in the NR group (n = 412). Within 28 d of therapy, 40 (9.7%) and 20 (6.6%) deaths were in the NR and FNC groups, respectively. No differences were observed between drugs and mortality rates (odds ratio [OR] 0.78, 95% CI 0.40-1.5, P = 0.45), clinical improvement (OR 0.79, 95% CI 0.79-1.3, P = 0.38), and clinical progression (OR 1.0, 95% CI 0.58-1.8, P = 0.96). More patients in the NR group experienced platelet decline than those in the FNC group (17.6% vs. 8.9%, P = 0.034). This study indicated that the effectiveness and safety of azvudine were comparable to those of nirmatrelvir-ritonavir.

Advancements in the Development of Anti-SARS-CoV-2 Therapeutics

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that causes COVID-19, and so far, it has occurred five noteworthy variants of concern (VOC). SARS-CoV-2 invades cells by contacting its Spike (S) protein to its receptor on the host cell, angiotensin-converting enzyme 2 (ACE2). However, the high frequency of mutations in the S protein has limited the effectiveness of existing drugs against SARS-CoV-2 variants, particularly the Omicron variant. Therefore, it is critical to develop drugs that have highly effective antiviral activity against both SARS-CoV-2 and its variants in the future. This review provides an overview of the mechanism of SARS-CoV-2 infection and the current progress on anti-SARS-CoV-2 drugs.

Efficacy of Azvudine Therapy in Patients with Severe and Non-Severe COVID-19: A Propensity Score-Matched Analysis

Objective

Azvudine is used to treat patients with the coronavirus disease 2019 (COVID-19). This study evaluated the clinical efficacy of azvudine in hospitalized patients with different severities of COVID-19 because few studies have described this in patients with severe and non-severe COVID-19.

Methods

This retrospective study included hospitalized patients with COVID-19 in Guizhou Provincial People's Hospital between December 2022 and January 2023. Azvudine-treated patients and controls were matched for sex, age, and disease severity at admission. Laboratory results and outcomes, including all-cause mortality, invasive mechanical ventilation, intensive care unit admission, and hospital stay length, were evaluated. Stratified analysis was used to explore the difference in the efficacy of azvudine in severe and non-severe COVID-19 patients.

Results

No significant differences in all-cause mortality were observed between the 303 azvudine recipients and 303 matched controls. However, azvudine-treated patients had shorter hospital stays (8.34±4.79 vs 9.17±6.25 days, P=0.046) and higher lymphocyte improvement rates (21.5% vs 13.9%, P=0.019), with a more pronounced effect in patients with non-severe COVID-19 (length of hospital stay, 8.07±4.35 vs 10.00±6.29 days, P=0.001; lymphocyte improvement rate, 23.8% vs 12.8%, P=0.015).

Conclusion

Azvudine treatment shortens hospital stay length and increases the rate of lymphocyte count improvement in patients with non-severe COVID-19, suggesting that azvudine may be a treatment option for these patients.

2'-Fluorinated nucleoside chemistry for new drug discovery: achievements and prospects

Fluorinated nucleosides are an important class of modified nucleosides that have demonstrated therapeutic potential for treating various human diseases, especially viral infections and cancer. Many fluorinated nucleosides have advanced into clinical trials or have been approved by the FDA for use in patients. Among these fluorinated nucleosides, azvudine, developed by us, has been officially approved by the National Medical Products Administration for the treatment of coronavirus disease 2019 (COVID-19) and human immunodeficiency virus, indicating the therapeutic promise of fluorinated nucleosides. In view of the therapeutic promise of fluorinated nucleosides for antiviral and anticancer therapy, in this Review we will provide a comprehensive overview of well-established 2'-fluorinated nucleosides approved for use in the market or those in clinical stages for antiviral and antitumor therapies, highlighting the drug discovery strategies, structure-activity relationship studies, mechanisms of action, and preclinical/clinical studies and also discuss the challenges and future directions for nucleoside-based new drug discovery.

Synthesis, Anti-TMV Activities, and Action Mechanisms of a Novel Cytidine Peptide Compound

Cytidine has a broad range of applications in the pharmaceutical field as an intermediate of antitumor or antiviral agent. Here, a series of new cytidine peptide compounds were synthesized using cytidine and Boc group-protected amino acids and analyzed for their antiviral activities against tobacco mosaic virus (TMV). Among these compounds, the structure of an effective antiviral cytidine peptide SN11 was characterized by 1H NMR, 13C NMR, and high-resolution mass spectrometer. The compound SN11 has a molecular formula of C15H22N6O8 and is named 2-amino-N-(2- ((1- (3,4-dihydroxy-5-(hydroxymethyl) tetrahydrofuran-2-yl) -2-oxo-1,2-dihydropyrimidin-4-yl) amino) -2-oxyethyl) amino). The protection, inactivation, and curation activities of SN11 at a concentration of 500 μg/mL against TMV in Nicotiana glutinosa were 82.6%, 84.2%, and 72.8%, respectively. SN11 also effectively suppressed the systemic transportation of a recombinant TMV carrying GFP reporter gene (p35S-30B:GFP) in Nicotiana benthamiana by reducing viral accumulation to 71.3% in the upper uninoculated leaves and inhibited the systemic infection of TMV in Nicotiana tabacum plants. Furthermore, the results of RNA-seq showed that compound SN11 induced differential expression of genes involved in the biogenesis and function of ribosome, plant hormone signal transduction, plant pathogen interaction, and chromatin. These results validate the antiviral mechanisms of the cytidine peptide compound and provide a theoretical basis for their potential application in the management of plant virus diseases.

A Real-World Retrospective Study on the Efficacy and Safety of Four Antiviral Drugs for Hospitalized COVID-19 Patients: Nirmatrelvir/Ritonavir, Simnotrelvir/Ritonavir, Molnupiravir and Azvudine

Purpose

This retrospective study aims to compare the effectiveness and safety of four oral antiviral drugs including Simnotrelvir/Ritonavir, Nirmatrelvir/Ritonavir, Azvudine and Molnupiravir in hospitalized patients with Coronavirus Disease 2019 (COVID-19) in a real-world setting, providing evidence to guide clinical practice against COVID-19.

Patients and Methods

Patients with mild or moderate COVID-19 hospitalized at Wuxi City's Second People's Hospital during December 2022 to June 2023 were included in this study. Patients were grouped by the antiviral drug received. The primary endpoint was the length of hospital stay. Patients were further divided into subgroups for stratified analysis, considering age, timing of medication, and drug mechanisms, to explore whether these factors could influence the treatment efficacy.

Results

Of the enrolled 195 patients receiving any treatment, 42 received Nirmatrelvir/Ritonavir, 33 received Molnupiravir, 81 received Simnotrelvir/Ritonavir, and 39 received Azvudine. Patients in Nirmatrelvir/Ritonavir and Simnotrelvir/Ritonavir groups had significantly shorter hospital stays compared to those in Azvudine group (P < 0.05). No significant difference was observed in hospital stays between those initiating antiviral therapy within or more than five days after symptom onset (P = 0.1109). Among patients with comorbidities, the Nirmatrelvir/Ritonavir and Simnotrelvir/Ritonavir group showed shorter hospital stays than the Azvudine group (P < 0.05). No serious treatment-related adverse events were observed across the groups.

Conclusion

In this retrospective study, Nirmatrelvir/Ritonavir and Simnotrelvir/Ritonavir exerts stronger potency on reducing duration of hospital stays in hospitalized patient with COVID-19, suggestive of a better choice for antiviral therapy. Patients who fail to take antiviral drugs in time after symptom onset would still benefit from these antiviral regimens. Additional well-designed clinical trials with large sample size are still needed to further confirm the effectiveness of these antivirals.

Lessons learnt from broad-spectrum coronavirus antiviral drug discovery

INTRODUCTION

Highly pathogenic coronaviruses (CoVs), such as severe acute respiratory syndrome CoV (SARS-CoV), Middle East respiratory syndrome CoV (MERS-CoV), and the most recent SARS-CoV-2 responsible for the COVID-19 pandemic, pose significant threats to human populations over the past two decades. These CoVs have caused a broad spectrum of clinical manifestations ranging from asymptomatic to severe distress syndromes (ARDS), resulting in high morbidity and mortality.

AREAS COVERED

The accelerated advancements in antiviral drug discovery, spurred by the COVID-19 pandemic, have shed new light on the imperative to develop treatments effective against a broad spectrum of CoVs. This perspective discusses strategies and lessons learnt in targeting viral non-structural proteins, structural proteins, drug repurposing, and combinational approaches for the development of antivirals against CoVs.

EXPERT OPINION

Drawing lessons from the pandemic, it becomes evident that the absence of efficient broad-spectrum antiviral drugs increases the vulnerability of public health systems to the potential onslaught by highly pathogenic CoVs. The rapid and sustained spread of novel CoVs can have devastating consequences without effective and specifically targeted treatments. Prioritizing the effective development of broad-spectrum antivirals is imperative for bolstering the resilience of public health systems and mitigating the potential impact of future highly pathogenic CoVs.

Identification of novel small-molecule inhibitors of SARS-CoV-2 by chemical genetics

There are only eight approved small molecule antiviral drugs for treating COVID-19. Among them, four are nucleotide analogues (remdesivir, JT001, molnupiravir, and azvudine), while the other four are protease inhibitors (nirmatrelvir, ensitrelvir, leritrelvir, and simnotrelvir-ritonavir). Antiviral resistance, unfavourable drug‒drug interaction, and toxicity have been reported in previous studies. Thus there is a dearth of new treatment options for SARS-CoV-2. In this work, a three-tier cell-based screening was employed to identify novel compounds with anti-SARS-CoV-2 activity. One compound, designated 172, demonstrated broad-spectrum antiviral activity against multiple human pathogenic coronaviruses and different SARS-CoV-2 variants of concern. Mechanistic studies validated by reverse genetics showed that compound 172 inhibits the 3-chymotrypsin-like protease (3CLpro) by binding to an allosteric site and reduces 3CLpro dimerization. A drug synergistic checkerboard assay demonstrated that compound 172 can achieve drug synergy with nirmatrelvir in vitro. In vivo studies confirmed the antiviral activity of compound 172 in both Golden Syrian Hamsters and K18 humanized ACE2 mice. Overall, this study identified an alternative druggable site on the SARS-CoV-2 3CLpro, proposed a potential combination therapy with nirmatrelvir to reduce the risk of antiviral resistance and shed light on the development of allosteric protease inhibitors for treating a range of coronavirus diseases.

Cost-effectiveness of Azvudine for High-risk Outpatients with Mild-to-moderate Coronavirus Disease 2019 in China

PURPOSE

This study aimed to evaluate the cost-effectiveness of Azvudine for the treatment of mild-to-moderate coronavirus disease 2019 in high-risk outpatients using real-world data and relevant references.

METHODS

In the decision-tree model, 2 cohorts were organized in a single center to compare the cost-effectiveness between the Azvudine plus symptomatic treatment group and the symptomatic treatment group. We calculated the cost and mortality rate for both groups. The incremental cost-effectiveness ratio was used to illustrate the cost-effectiveness. To assess the uncertainty of the model parameters, we conducted 1-way and probabilistic sensitivity analyses.

FINDINGS

In total, there were 804 outpatients included in the model. Among these, 317 patients received Azvudine plus symptomatic treatment, whereas the remaining 487 participants were treated with symptomatic treatment alone. The costs in the Azvudine and control groups were 1055.48 yuan and 2466.97 yuan and the survival rates were 100.00% and 98.70%, respectively. After calculation, the incremental cost-effectiveness ratio was determined to be -108,817.48 yuan per person. In the section of 1-way and probabilistic sensitivity analyses, Azvudine was still proven to be cost-effective.

IMPLICATIONS

Our results support the usage of Azvudine for the treatment of high-risk outpatients with mild-to-moderate coronavirus disease 2019 from economic perspective.

Repurposing existing drugs for the treatment ofCOVID-19/SARS-CoV-2: A review of pharmacological effects and mechanism of action

Following the coronavirus disease-2019 outbreak caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), there is an ongoing need to seek drugs that target COVID-19. First off, novel drugs have a long development cycle, high investment cost, and are high risk. Second, novel drugs must be evaluated for activity, efficacy, safety, and metabolic performance, contributing to the development cycle, investment cost, and risk. We searched the Cochrane COVID-19 Study Register (including PubMed, Embase, CENTRAL, ClinicalTrials.gov, WHO ICTRP, and medRxiv), Web of Science (Science Citation Index, Emerging Citation Index), and WHO COVID-19 Coronaviral Disease Global Literature to identify completed and ongoing studies as of February 20, 2024. We evaluated the pharmacological effects, in vivo and in vitro data of the 16 candidates in the paper. The difficulty of studying these candidates in clinical trials involving COVID-19 patients, dosage of repurposed drugs, etc. is discussed in detail. Ultimately, Metformin is more suitable for prophylactic administration or mildly ill patients; the combination of Oseltamivir, Tamoxifen, and Dexamethasone is suitable for moderately and severely ill patients; and more clinical trials are needed for Azvudine, Ribavirin, Colchicine, and Cepharanthine to demonstrate efficacy.

Etravirine Prevents West Nile Virus and Chikungunya Virus Infection Both In Vitro and In Vivo by Inhibiting Viral Replication

Diseases transmitted by arthropod-borne viruses such as West Nile virus (WNV) and chikungunya virus (CHIKV) pose threat to global public health. Unfortunately, to date, there is no available approved drug for severe symptoms caused by both viruses. It has been reported that reverse transcriptase inhibitors can effectively inhibit RNA polymerase activity of RNA viruses. We screened the anti-WNV activity of the FDA-approved reverse transcriptase inhibitor library and found that 4 out of 27 compounds showed significant antiviral activity. Among the candidates, etravirine markedly inhibited WNV infection in both Huh 7 and SH-SY5Y cells. Further assays revealed that etravirine inhibited the infection of multiple arboviruses, including yellow fever virus (YFV), tick-borne encephalitis virus (TBEV), and CHIKV. A deeper study at the phase of action showed that the drug works primarily during the viral replication process. This was supported by the strong interaction potential between etravirine and the RNA-dependent RNA polymerase (RdRp) of WNV and alphaviruses, as evaluated using molecular docking. In vivo, etravirine significantly rescued mice from WNV infection-induced weight loss, severe neurological symptoms, and death, as well as reduced the viral load and inflammatory cytokines in target tissues. Etravirine showed antiviral effects in both arthrophlogosis and lethal mouse models of CHIKV infection. This study revealed that etravirine is an effective anti-WNV and CHIKV arbovirus agent both in vitro and in vivo due to the inhibition of viral replication, providing promising candidates for clinical application.

Predictive Assessment of the Antiviral Properties of Imperata cylindrica against SARS-CoV-2

The omicron variant and its sublineages are highly contagious, and they still constitute a global source of concern despite vaccinations. Hospitalizations and mortality rates resulting from infections by these variants of concern are still common. The existing therapeutic alternatives have presented various setbacks such as low potency, poor pharmacokinetic profiles, and drug resistance. The need for alternative therapeutic options cannot be overemphasized. Plants and their phytochemicals present interesting characteristics that make them suitable candidates for the development of antiviral therapeutic agents. This study aimed to investigate the antiviral potential of Imperata cylindrica (I. cylindrica). Specifically, the objective of this study was to identify I. cylindrica phytochemicals that display inhibitory effects against SARS-CoV-2 main protease (Mpro), a highly conserved protein among coronaviruses. Molecular docking and in silico pharmacokinetic assays were used to assess 72 phytocompounds that are found in I. cylindrica as ligands and Mpro (6LU7) as the target. Only eight phytochemicals (bifendate, cylindrene, tabanone, siderin, 5-hydroxy-2-[2-(2-hydroxyphenyl)ethyl]-4H-1-benzopyran-4-one, maritimin, 5-methoxyflavone, and flavone) displayed high binding affinities with Mpro with docking scores ranging from -5.6 kcal/mol to -9.1 kcal/mol. The in silico pharmacokinetic and toxicological assays revealed that tabanone was the best and safest phytochemical for the development of an inhibitory agent against coronavirus main protease. Thus, the study served as a baseline for further in vitro and in vivo assessment of this phytochemical against Mpro of SARS-CoV-2 variants of concern to validate these in silico findings.

Effectiveness of azvudine against severe outcomes among hospitalized COVID-19 patients in Xinjiang, China: a single-center, retrospective, matched cohort study

BACKGROUND

Since the end of 2022, Azvudine was widely used to treat hospitalized coronavirus disease 2019 (COVID-19) patients in China. However, data on the real-world effectiveness of Azvudine against severe outcomes and post-COVID-19-conditions (PCC) among patients infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variants was limited. This study evaluates the effectiveness of Azvudine in hospitalized COVID-19 patients during a SARS-CoV-2 Omicron BA.5 dominance period.

METHODS

From 1 November 2022 to 1 July 2023, an SARS-CoV-2 Omicron BA.5 dominant period, we conducted a single-center retrospective cohort study based on hospitalized patients with laboratory-confirmed SARS-CoV-2 infection from a tertiary hospital in Shihezi, China. Patients treated with Azvudine and usual care were propensity-score matched (PSM) at a 1:1 ratio to a control group in which patients received usual care only, with matching based on covariates such as sex, age, ethnicity, number of preexisting conditions, antibiotic use at admission, and baseline complete blood cell count. The primary outcomes were all-cause death and short-term (60 days) PCC post discharge. The secondary outcomes included the initiation of invasive mechanical ventilation and PCC at long-term post discharge (120 days). Cox proportional hazards (PH) regression models were employed to estimate the hazard ratios (HR) of Azvudine treatment for both all-cause death and invasive mechanical ventilation, and logistic regression models were used to estimate the odds ratios (OR) for short-term and long-term PCC. Subgroup analyses were performed based on a part of the matched covariates.

RESULTS

A total of 2,639 hospitalized patients with SARS-CoV-2 infection were initially identified, and 2,069 ineligible subjects were excluded from analyses. After matching, 297 Azvudine recipients and 297 matched controls were eligible for analyses. The incidence rate of all-cause death was relatively lower in the Azvudine group than in control group (0.007 per person, 95% confidence interval [CI]: 0.001, 0.024 vs 0.128, 95% CI: 0.092, 0.171), and the use of Azvudine was associated with a significantly lower risk of death (HR: 0.049, 95% CI: 0.012, 0.205). Subgroup analyses suggested protection of Azvudine against the risks of all-cause death among men, age over 65, patients without the preexisting conditions, and patients with antibiotics dispensed at admission. Statistical differences were not observed between the Azvudine group and the control group for the risks of invasive mechanical ventilation or short and long-term PCC.

CONCLUSIONS

Our findings indicated that Azvudine was associated with lower risk of all-cause death among hospitalized patients with Omicron BA.5 infection in a real-world setting. Further investigation is needed to explore the effectiveness of Azvudine against the PCC after discharge.

Selectively T cell phosphorylation activation of azvudine in the thymus tissue with immune protection effect

Thymus is the important immune organ, responsible for T cell development and differentiation. The lower circulating T counts have been observed in patients who died from COVID-19 compared with survivors. Azvudine, also known as FNC, is a thymus-homing anti-SARS-CoV-2 drug in treating COVID-19 patients. In this study, single-cell transcriptome, proteomics, and parallel reaction monitoring (PRM) were applied to insight into the activation process of FNC in rat and SARS-CoV-2 rhesus monkey thymus. The results indicated that thymic immune cells possess a robust metabolic capacity for cytidine-analogue drugs such as FNC. Key enzymes involved in the FNC phosphorylation process, such as Dck, Cmpk1, and Nme2, were highly expressed in CD4+ T cells, CD8+ T cells, and DP (CD4+ CD8+) cells. Additionally, FNC could upregulate multiple phosphorylated kinases in various cell types while downregulating the phosphatases, phosphoribosyl transferases, and deaminases, respectively. The robust phosphorylation capacity of the thymus for cytidine analogue drug FNC, and the activation effect of FNC on the NAs metabolism system potentially contribute to its enrichment in the thymus and immune protection effect. This suggests that it is crucial to consider the expression level of phosphorylation kinases when evaluating NA drug properties, as an important factor during antiviral drug design.

Efficacy and Safety of Azvudine in Patients With COVID-19 in China: A Meta-Analysis of Observational Studies

BACKGROUND

Azvudine (FNC) is a novel small molecule antiviral drug for treating COVID-19 that is available only on the Chinese market. Despite being recommended for treating COVID-19 by the Chinese guidelines, its efficacy and safety are still unclear. This study aimed to evaluate the protective effect of FNC on COVID-19 outcomes and its safety.

METHODS

We followed the PRISMA 2020 guidelines and searched the PubMed, Embase, Web of Science, Scopus, and China National Knowledge Infrastructure (CNKI) databases to evaluate studies on the effectiveness of FNC in treating COVID-19 in China, focusing on mortality and overall outcomes. Additionally, its impact on the length of hospital stay (LOHS), time to first nucleic acid negative conversion (T-FNANC), and adverse events was evaluated. The inclusion criterion was that the studies were published from July 2021 to April 10, 2024. This study uses the ROBINS-I tool to assess bias risk and employs the GRADE approach to evaluate the certainty of the evidence.

RESULTS

The meta-analysis included 24 retrospective studies involving a total of 11 830 patients. Low-certainty evidence revealed no significant difference in mortality (OR = 0.91, 95% CI: 0.76-1.08) or LOHS (WMD = -0.24, 95% CI: -0.83 to 0.35) between FNC and Paxlovid in COVID-19 patients. Low-certainty evidence shows that the T-FNANC was longer (WMD = 1.95, 95% CI: 0.36-3.53). Compared with the Paxlovid group, low-certainty evidence shows the FNC group exhibited a worse composite outcome (OR = 0.77, 95% CI: 0.63-0.95) and fewer adverse events (OR = 0.63, 95% CI: 0.46-0.85). Compared with supportive treatment, low certainty shows FNC significantly reduced the mortality rate in COVID-19 patients (OR = 0.61, 95% CI: 0.51-0.74) and decreased the composite outcome (OR = 0.67, 95% CI: 0.50-0.91), and very low certainty evidence shows significantly decreased the T-FNANC (WMD = -4.62, 95% CI: -8.08 to -1.15). However, in very low certainty, there was no significant difference in LOHS (WMD = -0.70, 95% CI: -3.32 to 1.91) or adverse events (OR = 1.97, 95% CI: 0.48-8.17).

CONCLUSIONS

FNC appears to be a safe and potentially effective treatment for COVID-19 in China, but further research with larger, high-quality studies is necessary to confirm these findings. Due to the certainty of the evidence and the specific context of the studies conducted in China, caution should be exercised when considering whether the results are applicable worldwide.

TRIAL REGISTRATION

PROSPERO number: CRD42024520565.

Effectiveness and safety of azvudine in COVID-19: A systematic review and meta-analysis

OBJECTIVE

The aim of this study was to assess the effectiveness and safety of azvudine in treating coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-COV-2).

METHODS

A search was carried out in PubMed, Cochrane Library, Web of Science, medRxiv, and Google Scholar until October 20, 2023. The Cochrane risk of bias tools were used to assess the quality of included studies. Comprehensive Meta-Analysis software was used to analyze data.

RESULTS

Twenty-one studies including 10,011 patients were examined. The meta-analysis results showed that azvudine and standard of care/placebo (SOC/PBO) were significantly different concerning mortality rate (risk ratio [RR] = 0.48, 95% confidence interval [CI]: 0.40 to 0.57) and negative polymerase chain reaction (PCR) conversion time (standard mean difference = - 0.75, 95% CI: -1.29 to-0.21). However, the two groups did not show significant differences concerning hospital stay, intensive care unit (ICU) admission, and need for mechanical ventilation (P > 0.05). On the other hand, azvudine and nirmatrelvir-ritonavir were significantly different in mortality rate (RR = 0.73, 95% CI: 0.58 to 0.92), ICU admission (RR = 0.41, 95% CI: 0.21 to 0.78), and need for mechanical ventilation (RR = 0.67, 95% CI: 0.51 to 0.89), but the two treatments were not significantly different in negative PCR conversion time, and hospital stay (P > 0.05). The incidence of adverse events between groups was not significant (P > 0.05). The certainty of evidence was rated as low or moderate.

CONCLUSIONS

The antiviral effectiveness of azvudine against SARS-COV-2 is questionable with regard to the certainty of evidence. Further research should be conducted to establish the effectiveness and safety of azvudine in COVID-19.

Azvudine for the Treatment of COVID-19 in Pre-Existing Cardiovascular Diseases: A Single-Center, Real-World Experience

COVID-19 can lead to adverse outcomes in patients with pre-existing diseases. Azvudine has been approved for treating COVID-19 in China, but the real-world data is limited. It is aimed to investigate the efficacy of Azvudine in patients with COVID-19 and pre-existing cardiovascular diseases. Patients with confirmed COVID-19 and pre-existing cardiovascular diseases are retrospectively enrolled. The primary outcome is all-cause death during hospitalization. Overall, 351 patients are included, with a median age of 74 years, and 44% are female. 212 (60.6%) patients are severe cases. Azvudine is used in 106 (30.2%) patients and not in 245 (69.8%). 72 patients died during hospitalization. After multivariate adjustment, patients who received Azvudine a lower risk of all-cause death (hazard ratio: 0.431; 95% confidence interval: 0.252-0.738; p = 0.002) than controls. Azvudine therapy is also associated with lower risks of shock and acute kidney injury. For sensitivity analysis in the propensity score-matched cohort (n = 90 for each group), there is also a significant difference in all-cause death between the two groups (hazard ratio: 0.189; 95% confidence interval: 0.071-0.498; p < 0.001). This study indicated that Azvudine therapy is associated with better outcomes in COVID-19 patients with pre-existing cardiovascular diseases.

Carrimycin inhibits coronavirus replication by decreasing the efficiency of programmed -1 ribosomal frameshifting through directly binding to the RNA pseudoknot of viral frameshift-stimulatory element

The pandemic of SARS-CoV-2 worldwide with successive emerging variants urgently calls for small-molecule oral drugs with broad-spectrum antiviral activity. Here, we show that carrimycin, a new macrolide antibiotic in the clinic and an antiviral candidate for SARS-CoV-2 in phase III trials, decreases the efficiency of programmed -1 ribosomal frameshifting of coronaviruses and thus impedes viral replication in a broad-spectrum fashion. Carrimycin binds directly to the coronaviral frameshift-stimulatory element (FSE) RNA pseudoknot, interrupting the viral protein translation switch from ORF1a to ORF1b and thereby reducing the level of the core components of the viral replication and transcription complexes. Combined carrimycin with known viral replicase inhibitors yielded a synergistic inhibitory effect on coronaviruses. Because the FSE mechanism is essential in all coronaviruses, carrimycin could be a new broad-spectrum antiviral drug for human coronaviruses by directly targeting the conserved coronaviral FSE RNA. This finding may open a new direction in antiviral drug discovery for coronavirus variants.

Update on Omicron variant and its threat to vulnerable populations

Objective

To reduce the incidence of severe illness and fatalities, and promote the awareness of protection and precaution, increased vaccination, strengthen the physical fitness, frequent ventilation, and health education should be enhanced among vulnerable populations as essential measures for the future control of COVID-19.

Study design

Systematic review.

Method

The search was done using PubMed, EMBASE and Web of Science for studies without language restrictions, published up through March 2023, since their authoritative and comprehensive literature search database. Eighty articles were included. Extraction of articles and quality assessment of included reviews was performed independently by two authors using the AMSTAR 2 score.

Results

The articles in the final data set included research on epidemiological characteristics, pathogenicity, available vaccines, treatments and epidemiological features in special populations including the elders, pregnant women, kids, people with chronic diseases concerning Omicron.

Conclusion

Although less pathogenic potential is found in Omicron, highly mutated forms have enhanced the ability of immune evasion and resistance to existing vaccines compared with former variants. Severe complications and outcomes may occur in vulnerable populations. Infected pregnant women are more likely to give birth prematurely, and fatal implications in children infected with Omicron are hyperimmune response and severe neurological disorders. In immunocompromised patients, there is a greater reported mortality and complication compared to patients with normal immune systems. Therefore, maintain social distancing, wear masks, and receive vaccinations are effective long-term measures.

Adherence and recommended optimal treatment to Azvudine application for the treatment of outpatient COVID-19 patients: A real-world retrospective study

Background

Azvudine was approved for the treatment of coronavirus disease 2019 (COVID-19) in China and has been widely used since the outbreak in December 2022. However, real-world research on the adherence of Azvudine is lacking. Additionally, limited research exists on determining the optimal duration for Azvudine treatment.

Methods

We studied adult patients with COVID-19 who got Azvudine or supportive treatment at an outpatient department between December 19, 2022 and January 5, 2023. The enrolled patients were divided into two groups: the Azvudine group, which received Azvudine, and the control group, which only received supportive care. We recorded their information and analyzed it using descriptive statistics. The primary outcome of this study was the compliance of outpatients with Azvudine, and the secondary outcome of this study was the optimal duration of Azvudine. Inverse probability weighting (IPW) was used to address the imbalance between groups when comparing the optimal duration of Azvudine, and Cox regression to evaluate the effect of Azvudine on the 28-day disease progression rate.

Results

We enrolled a total of 882 patients, of which 382 received Azvudine. Among the patients, 94.0 % (359) had good compliance, and non-compliance was primarily attributed to dosage errors. Azvudine appeared to have a beneficial therapeutic effect when administered for at least 7 days.

Conclusions

Outpatients have relatively good compliance with Azvudine, and optimal therapeutic effects were observed with the recommended duration of at least 7 days.

Review of COVID-19 Therapeutics by Mechanism: From Discovery to Approval

The global research and pharmaceutical community rapidly mobilized to develop treatments for coronavirus disease 2019 (COVID-19). Existing treatments have been repurposed and new drugs have emerged. Here we summarize mechanisms and clinical trials of COVID-19 therapeutics approved or in development. Two reviewers, working independently, reviewed published data for approved COVID-19 vaccines and drugs, as well as developmental pipelines, using databases from the following organizations: United States Food and Drug Administration (US-FDA), European Medicines Agency (EMA), Japanese Pharmaceutical and Medical Devices Agency (PMDA), and ClinicalTrials.gov. In all, 387 drugs were found for initial review. After removing unrelated trials and drugs, 66 drugs were selected, including 17 approved drugs and 49 drugs under development. These drugs were classified into six categories: 1) drugs targeting the viral life cycle 2) Anti-severe acute respiratory syndrome coronavirus 2 Monoclonal Antibodies, 3) immunomodulators, 4) anti-coagulants, 5) COVID-19-induced neuropathy drugs, and 6) other therapeutics. Among the 49 drugs under development are the following: 6 drugs targeting the viral life cycle, 12 immunosuppression drugs, 2 immunostimulants, 2 HIF-PHD targeting drugs, 3 GM-CSF targeting drugs, 5 anti-coagulants, 2 COVID-19-induced neuropathy drugs, and 17 others. This review provides insight into mechanisms of action, properties, and indications for COVID-19 medications.

Selective Hydrofunctionalization of Alkenyl Fluorides Enabled by Nickel-Catalyzed Hydrogen Atoms and Group Transfer: Reaction Development and Mechanistic Study

Due to the unique effect of fluorine atoms, the efficient construction of high-value alkyl fluorides has attracted significant interest in modern drug development. However, enantioselective catalytic strategies for the efficient assembly of highly functionalized chiral C(sp3)-F scaffolds from simple starting materials have been underutilized. Herein, we demonstrate a nickel-catalyzed radical transfer strategy for the efficient, modular, asymmetric hydrogenation and hydroalkylation of alkenyl fluorides with primary, secondary, and tertiary alkyl halides under mild conditions. The transformation provides facile access to various structurally complex secondary and tertiary α-fluoro amide products from readily available starting materials with excellent substrate compatibility and distinct selectivity. Furthermore, the utility of this method is demonstrated by late-stage modifications and product derivatizations. Detailed mechanistic studies and DFT calculations have been conducted, showing that the rate-determining step for asymmetric hydrogenation reaction is NiH-HAT toward alkenyl fluorides and the stereo-determining step is alcohol coordination to Ni-enolates followed by a barrierless protonation. The mechanism for the asymmetric hydroalkylation reaction is also delivered in this investigation.

Mild Approach to Nucleoside Analogues via Photoredox/Cu-Catalyzed Decarboxylative C-N Bond Formation. Total Synthesis of Oxetanocin A

The conventional N-glycosylation methods for nucleoside synthesis usually require strongly acidic or basic conditions. Here we report the decarboxylative C(sp3)-N coupling of glycosyl N-hydroxyphthalimide esters with nucleobases via dual photoredox/Cu catalysis, which offered a mild approach to nucleoside analogues. A total synthesis of oxetanocin A, an antiviral natural product containing an oxetanose moiety, has been achieved by using this method.