Antiviral Therapy of COVID-19

IFN-γ derived from activated human CD4+ T cells inhibits the replication of SARS-CoV-2 depending on cell-type and viral strain

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination elicit both T cell and B cell immune responses in immunocompetent individuals. However, the mechanisms underlying the antiviral effects mediated by CD4+ T cells are not fully understood. In this study, we analyzed the culture supernatant (SN) from polyclonally stimulated human CD4+ T cells as a model for soluble mediators derived from SARS-CoV-2-stimulated CD4+ T cells. Interestingly, this SN inhibited SARS-CoV-2 propagation in a viral strain- and host cell type-dependent manner. The original wild-type showed the highest susceptibility, whereas the Delta variant exhibited resistance in the human monocyte cell line. In addition, antibody-dependent enhancement (ADE) of infection with the original strain was also abolished in the presence of the SN. The findings showed that the inhibitory effect on viral propagation by the SN was mostly attributed to interferon-γ (IFN-γ) that was present in the SN. These results highlight the potential role of IFN-γ as an anti-SARS-CoV-2 mediator derived from CD4+ T cells, and suggest that we need to understand the SARS-CoV-2 strain-dependent sensitivity to IFN-γ in controlling clinical outcomes. In addition, characterization of new SARS-CoV-2 variants in terms of IFN-γ-sensitivity will have important implications for selecting therapeutic strategies.

Impact of early antiviral therapy on SARS-CoV-2 clearance time in high-risk COVID-19 subjects: A propensity score matching study

BACKGROUND

Effective treatments for COVID-19 are needed to mitigate disease progression and reduce the burden on healthcare systems. This study investigates the impact of early treatments on SARS-CoV-2 viral shedding duration among high-risk individuals with mild symptoms.

METHODS

A single-center, retrospective observational study was conducted at Luigi Sacco Hospital in Milan from December 2021 to March 2023. Hospitalized and nonhospitalized adults with a confirmed SARS-CoV-2 infection and at high-risk of disease progression were enrolled. Unadjusted and adjusted negative binomial regression models and a Random Forest regression model were performed before and after matching subjects based on their propensity of being treated or not.

RESULTS

Results from 518 subjects (428 treated and 90 untreated) revealed a significant reduction in SARS-CoV-2 viral shedding duration among those who received early treatment compared to untreated individuals. Propensity score matching and multivariable regression analyses confirmed this finding. Early treatment significantly reduced the risk of COVID-19-related hospitalization and pneumonia development. Subgroup analysis identified COPD as a potential factor influencing effectiveness of early treatments.

CONCLUSIONS

Early treatments play a crucial role in reducing SARS-CoV-2 viral shedding and preventing disease progression among high-risk individuals. Shorter viral shedding duration also contributes to improved healthcare resource utilization and infection control measures.

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.

Cardiovascular Drug Interactions with Nirmatrelvir/Ritonavir for COVID-19: Considerations for Daily Practice

Cardiovascular disease is associated with progression to severe COVID-19 and patients with the condition are among those in whom early antiviral therapy should be warranted. The combination of nirmatrelvir/ritonavir (Paxlovid®) has been approved for clinical use by the Food and Drug Administration and European Medicines Agency. Because patients with cardiovascular disease are often on polypharmacy, physicians need to be aware of potential drug-drug interactions (DDIs) when treating COVID-19 with nirmatrelvir/ritonavir. Guidance is given for avoiding DDIs, emphasising that preventing and managing potential DDIs with nirmatrelvir/ritonavir requires thorough assessment and knowledge. The present review summarises the clinical pharmacology of nirmatrelvir/ritonavir and provides details on potential DDIs with a focus on daily practice in patients with cardiovascular disease. Particular attention is needed for drugs that are predominantly metabolised by cytochrome P450 3A4, are substrates of P-glycoprotein and have a narrow therapeutic index. Proper management of potential DDIs must balance the benefit of nirmatrelvir/ ritonavir to prevent severe disease with the risk of serious adverse events.

Research Progress on Sesquiterpene Compounds from Artabotrys Plants of Annonaceae

Artabotrys, a pivotal genus within the Annonaceae family, is renowned for its extensive biological significance and medicinal potential. The genus's sesquiterpene compounds have attracted considerable interest from the scientific community due to their structural complexity and diverse biological activities. These compounds exhibit a range of biological activities, including antimalarial, antibacterial, anti-inflammatory analgesic, and anti-tumor properties, positioning them as promising candidates for medical applications. This review aims to summarize the current knowledge on the variety, species, and structural characteristics of sesquiterpene compounds isolated from Artabotrys plants. Furthermore, it delves into their pharmacological activities and underlying mechanisms, offering a comprehensive foundation for future research.

The metabolic footprint of Vero E6 cells highlights the key metabolic routes associated with SARS-CoV-2 infection and response to drug combinations

SARS-CoV-2 burdens healthcare systems worldwide, yet specific drug-based treatments are still unavailable. Understanding the effects of SARS-CoV-2 on host molecular pathways is critical for providing full descriptions and optimizing therapeutic targets. The present study used Nuclear Magnetic Resonance-based metabolic footprinting to characterize the secreted cellular metabolite levels (exometabolomes) of Vero E6 cells in response to SARS-CoV-2 infection and to two candidate drugs (Remdesivir, RDV, and Azithromycin, AZI), either alone or in combination. SARS-CoV-2 infection appears to force VE6 cells to have increased glucose concentrations from extra-cellular medium and altered energetic metabolism. RDV and AZI, either alone or in combination, can modify the glycolic-gluconeogenesis pathway in the host cell, thus impairing the mitochondrial oxidative damage caused by the SARS-CoV-2 in the primary phase. RDV treatment appears to be associated with a metabolic shift toward the TCA cycle. Our findings reveal a metabolic reprogramming produced by studied pharmacological treatments that protects host cells against virus-induced metabolic damage, with an emphasis on the glycolytic-gluconeogenetic pathway. These findings may help researchers better understand the relevant biological mechanisms involved in viral infection, as well as the creation of mechanistic hypotheses for such candidate drugs, thereby opening up new possibilities for SARS-CoV-2 pharmacological therapy.

Favipiravir, remdesivir, and lopinavir: metabolites, degradation products and their analytical methods

Severe acute respiratory syndrome 2 (SARS-CoV-2) caused the emergence of the COVID-19 pandemic all over the world. Several studies have suggested that antiviral drugs such as favipiravir (FAV), remdesivir (RDV), and lopinavir (LPV) may potentially prevent the spread of the virus in the host cells and person-to-person transmission. Simultaneously with the widespread use of these drugs, their stability and action mechanism studies have also attracted the attention of many researchers. This review focuses on the action mechanism, metabolites and degradation products of these antiviral drugs (FAV, RDV and LPV) and demonstrates various methods for their quantification and discrimination in the different biological samples. Herein, the instrumental methods for analysis of the main form of drugs or their metabolite and degradation products are classified into two types: optical and chromatography methods which the last one in combination with various detectors provides a powerful method for routine and stability analyses. Some representative studies are reported in this review and the details of them are carefully explained. It is hoped that this review will be a good guideline study and provide a better understanding of these drugs from the aspects investigated in this study.

Hyperimmune Plasma and Immunoglobulins against COVID-19: A Narrative Review

Since late 2019, the new SARS-CoV-2 virus belonging to the Coronaviridae family has been responsible for COVID-19 pandemic, a severe acute respiratory syndrome. Several antiviral therapies, mostly derived from previous epidemics, were initially repurposed to fight this not rarely life-threatening respiratory illness. Among them, however, the only specific antibody-based therapy available against SARS-CoV-2 infection during the first year of the pandemic was represented by COVID-19 convalescent plasma (CCP). CCP, collected from recovered individuals, contains high levels of polyclonal antibodies of different subclasses able to neutralize SARS-CoV-2 infection. Tens of randomized controlled trials have been conducted during the last three years of the pandemic to evaluate the safety and the clinical efficacy of CCP in both hospitalized and ambulatory COVID-19 patients, whose main results will be summarized in this narrative review. In addition, we will present the current knowledge on the development of anti-SARS-CoV-2 hyperimmune polyclonal immunoglobulins.

SARS-CoV-2 Specific Nanobodies Neutralize Different Variants of Concern and Reduce Virus Load in the Brain of h-ACE2 Transgenic Mice

Since the beginning of the COVID-19 pandemic, there has been a significant need to develop antivirals and vaccines to combat the disease. In this work, we developed llama-derived nanobodies (Nbs) directed against the receptor binding domain (RBD) and other domains of the Spike (S) protein of SARS-CoV-2. Most of the Nbs with neutralizing properties were directed to RBD and were able to block S-2P/ACE2 interaction. Three neutralizing Nbs recognized the N-terminal domain (NTD) of the S-2P protein. Intranasal administration of Nbs induced protection ranging from 40% to 80% after challenge with the WA1/2020 strain in k18-hACE2 transgenic mice. Interestingly, protection was associated with a significant reduction in virus replication in nasal turbinates and a reduction in virus load in the brain. Employing pseudovirus neutralization assays, we identified Nbs with neutralizing capacity against the Alpha, Beta, Delta, and Omicron variants, including a Nb capable of neutralizing all variants tested. Furthermore, cocktails of different Nbs performed better than individual Nbs at neutralizing two Omicron variants (B.1.529 and BA.2). Altogether, the data suggest the potential of SARS-CoV-2 specific Nbs for intranasal treatment of COVID-19 encephalitis.

Prospective Antiviral Effect of Ulva lactuca Aqueous Extract against COVID-19 Infection

Marine algal extracts exhibit a potent inhibitory effect against several enveloped and non-enveloped viruses. The infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has several adverse effects, including an increased mortality rate. The anti-COVID-19 agents are still limited; this issue requires exploring novel, effective anti-SARS-CoV-2 therapeutic approaches. This study investigated the antiviral activity of an aqueous extract of Ulva lactuca, which was collected from the Gulf of Suez, Egypt. The aqueous extract of Ulva lactuca was characterized by high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Energy Dispersive X-ray (EDX) analyses. According to the HPLC analysis, the extract comprises several sugars, mostly rhamnose (32.88%). The FTIR spectra showed numerous bands related to the functional groups. EDX analysis confirmed the presence of different elements, such as oxygen (O), carbon (C), sulfur (S), magnesium (Mg), potassium (K), calcium (Ca), and sodium (Na), with different concentrations. The aqueous extract of U. lactuca (0.0312 mg/mL) exhibited potent anti-SARS-CoV-2 activity via virucidal activity, inhibition of viral replication, and interference with viral adsorption (% inhibitions of 64%, 33.3%, and 31.1%, respectively). Consequently, ulvan could be a promising compound for preclinical study in the drug development process to combat SARS-CoV-2.

Strategies for the development and approval of COVID-19 vaccines and therapeutics in the post-pandemic period

The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in significant casualties and put immense strain on public health systems worldwide, leading to economic recession and social unrest. In response, various prevention and control strategies have been implemented globally, including vaccine and drug development and the promotion of preventive measures. Implementing these strategies has effectively curbed the transmission of the virus, reduced infection rates, and gradually restored normal social and economic activities. However, the mutations of SARS-CoV-2 have led to inevitable infections and reinfections, and the number of deaths continues to rise. Therefore, there is still a need to improve existing prevention and control strategies, mainly focusing on developing novel vaccines and drugs, expediting medical authorization processes, and keeping epidemic surveillance. These measures are crucial to combat the Coronavirus disease (COVID-19) pandemic and achieve sustained, long-term prevention, management, and disease control. Here, we summarized the characteristics of existing COVID-19 vaccines and drugs and suggested potential future directions for their development. Furthermore, we discussed the COVID-19-related policies implemented over the past years and presented some strategies for the future.

Prolonged SARS-CoV-2 infection during obinutuzumab and bendamustine treatment for follicular lymphoma: A case report

Key Clinical Message

SARS-CoV-2 infection has been associated with a prolonged course and a poor prognosis in patients who receive anti-CD20 antibodies. However, there are no established treatments for such patients. Serial changes in the SARS-CoV-2 antigen titer during the clinical course and treatment strategies for immunosuppressed patients are discussed.

Abstract

We report a case of prolonged SARS-CoV-2 infection during obinutuzumab and bendamustine treatment for follicular lymphoma. Four years previously, the patient had been diagnosed with follicular lymphoma (Stage IIIA, Grade 2). She received several chemotherapy regimens, including rituximab and radiation therapy. Although these therapies achieved complete response temporally, they did not continue and recurred at 8 months before. Obinutuzumab and bendamustine therapy was selected, and she received five courses of obinutuzumab and bendamustine. She also received a SARS-CoV-2 mRNA vaccine two times. Although she did not have any symptoms, a routine check-up just before the 6th course of obinutuzumab and bendamustine revealed SARS-CoV-2 infection. Because she was immunosuppressed and was considered to be at high risk for the exacerbation of her disease, molnupiravir was immediately administered, and her SARS-CoV-2 antigen decreased. However, it was not completely cleared and flared-up at 6 weeks, with symptoms of COVID-19 appearing. Despite intensive treatment for SARS-CoV-2 infection, including remdesivir, baricitinib, tocilizumab and intravenous immunoglobulin, her SARS-CoV-2 antigen titer never became negative, and she finally died of respiratory failure caused by prolonged SARS-CoV-2 infection. Serial changes in the SARS-CoV-2 antigen titer during the clinical course and treatment strategies for immunosuppressed patients are discussed.

Synergistic Activity of Remdesivir-Nirmatrelvir Combination on a SARS-CoV-2 In Vitro Model and a Case Report

BACKGROUND

This study aims to investigate the activity of the remdesivir-nirmatrelvir combination against Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) and to report a case of Coronavirus Disease 2019 (COVID-19) cured with this combination.

METHODS

A Vero E6 cell-based infection assay was used to investigate the in vitro activity of the remdesivir-nirmatrelvir combination. The SARS-CoV-2 strains tested were 20A.EU1, BA.1 and BA.5. After incubation, a viability assay was performed. The supernatants were collected and used for viral titration. The Highest Single Agent (HSA) reference model was calculated. An HSA score >10 is considered synergic.

RESULTS

Remdesivir and nirmatrelvir showed synergistic activity at 48 and 72 h, with an HSA score of 52.8 and 28.6, respectively (p < 0.0001). These data were confirmed by performing supernatant titration and against the omicron variants: the combination reduced the viral titer better than the more active compound alone. An immunocompromised patient with prolonged and critical COVID-19 was successfully treated with remdesivir, nirmatrelvir/ritonavir, tixagevimab/cilgavimab and dexamethasone, with an excellent clinical-radiological response. However, she required further off-label prolonged therapy with nirmatrelvir/ritonavir until she tested negative.

CONCLUSIONS

Remdesivir-nirmatrelvir combination has synergic activity in vitro. This combination may have a role in immunosuppressed patients with severe COVID-19 and prolonged viral shedding.