Safety and Efficacy of Antiviral Drugs for the Treatment of COVID-19: A Systematic Review

Electrophysiological and sick sinus syndrome effects of Remdesivir challenge in guinea-pig hearts

Remdesivir (RDV) is the first drug approved by the FDA for clinical treatment of hospitalized patients infected with COVID-19 because it has been shown to have good antiviral activity against a variety of viruses, including Arenaviridae and Coronaviridae viral families. However, it has been reported that its clinical treatment leads to the symptoms of sick sinus syndrome such as sinus bradycardia, conduction block, and sinus arrest, but the electrophysiological mechanism of its specific cardiac adverse events is still unclear. We report complementary, experimental, studies of its electrophysiological effects. In wireless cardiac telemetry experiments in vivo and electrocardiographic studies in ex vivo cardiac preparations, RDV significantly caused sinus bradycardia, sinus atrial block, and prolongation of the QT interval in guinea pigs. Dose-dependent effects of RDV on the electrical activities of sinoatrial node (SA node) preparations of guinea pigs were characterised by multielectrode, optical RH237 voltage mapping. These revealed reversibly reduced sinoatrial conduction time (SACT), increased AP durations (APDs), and decreased the pacemaking rate of the SA node. Patch-clamp experiments showed that RDV significantly inhibited the If current of HCN4 channels, resulting in a significant decrease in the spontaneous firing rate of SA node cells, which may underlie the development of sick sinus node syndrome. In addition, RDV significantly inhibits IKr currents in hERG channels, leading to prolongation of the QT interval and playing a role in bradycardia. Therefore, these findings provide insights into the understanding the bradycardia effect of RDV, which may be used as basic theoretical guidance for the intervention of its adverse events, and prompt safety investigations of RDV's cardiac safety in the future.

Long-Lasting SARS-CoV-2 Infection With Post-COVID-19 Chronic Interstitial Pneumonia in a Patient With Chronic Lymphocytic Leukemia Treated Successfully With Intravenous Immunoglobulin

Post-coronavirus disease 2019 (post-COVID-19) condition is a post-acute syndrome characterized by non-specific symptoms that remain for at least two months and typically appear three months after the start of the acute phase. Individuals with chronic lymphocytic leukemia (CLL) are considered to be at high risk of contracting COVID-19. It is also becoming increasingly evident that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine response is frequently lacking or insufficient. We present a 77-year-old male patient with CLL who had multiple hospitalizations for the management of pneumonia related to persistent COVID-19 infection due to hypogammaglobulinemia. He was subsequently treated with intravenous immunoglobulin (IVIG). This case emphasizes the importance of the early detection of hypogammaglobulinemia in patients with CLL and long COVID because of the potential therapeutic benefit of IVIG therapy. We also provide a literature review on COVID-19 infection in CLL patients, focusing mainly on the subset population of patients with hypergammaglobulinemia.

Impact of some antiviral drugs on health care utilization for patients with COVID-19: a systematic review and meta-analysis

BACKGROUND

We aimed to assess the impact of antiviral drugs (fluvoxamine,remdesivir, lopinavir/ritonavir (LPV/r), molnupiravir, andnirmatrelvir/ritonavir (NRV/r)) on health care utilization (HCU) inCOVID-19 patients. We summarized findings from randomized controlledtrials (RCTs) and observational studies.

METHODS

We systematically searched four medical databases (PubMed, Web of Science, Embase, Cochrane Library) for COVID-19 studies up to February 15, 2023. A comprehensive review, meta-analysis, sensitivity analysis, and subgroup analysis were conducted. Pooled effects with 95% confidence intervals (CIs) were calculated for antiviral drugs' impact on hospitalization, mechanical ventilation (MV), and intensive care unit (ICU) outcomes.

RESULTS

Our analysis included 34 studies (584,978 patients). Meta-analysisindicated potential benefits: remdesivir and molnupiravir potentiallyreduced MV risk, and NRV/r correlated with lower hospitalizationrates. However, LPV/r did not notably curb HCU. Remdesivir waspreferable for high-risk COVID-19 patients, while molnupiravir andNRV/r were recommended for those aged 60 and above.

CONCLUSION

Remdesivir, molnupiravir, and NRV/r may reduce HCU during the COVID-19 pandemic. However, due to limited study details and significant heterogeneity in effect estimates, further precise evidence is crucial, especially concerning emerging variants.

Viral target and metabolism-based rationale for combined use of recently authorized small molecule COVID-19 medicines: Molnupiravir, nirmatrelvir, and remdesivir

The COVID-19 pandemic remains a major health concern worldwide, and SARS-CoV-2 is continuously evolving. There is an urgent need to identify new antiviral drugs and develop novel therapeutic strategies. Combined use of newly authorized COVID-19 medicines including molnupiravir, nirmatrelvir, and remdesivir has been actively pursued. Mechanistically, nirmatrelvir inhibits SARS-CoV-2 replication by targeting the viral main protease (Mpro ), a critical enzyme in the processing of the immediately translated coronavirus polyproteins for viral replication. Molnupiravir and remdesivir, on the other hand, inhibit SARS-CoV-2 replication by targeting RNA-dependent RNA-polymerase (RdRp), which is directly responsible for genome replication and production of subgenomic RNAs. Molnupiravir targets RdRp and induces severe viral RNA mutations (genome), commonly referred to as error catastrophe. Remdesivir, in contrast, targets RdRp and causes chain termination and arrests RNA synthesis of the viral genome. In addition, all three medicines undergo extensive metabolism with strong therapeutic significance. Molnupiravir is hydrolytically activated by carboxylesterase-2 (CES2), nirmatrelvir is inactivated by cytochrome P450-based oxidation (e.g., CYP3A4), and remdesivir is hydrolytically activated by CES1 but covalently inhibits CES2. Additionally, remdesivir and nirmatrelvir are oxidized by the same CYP enzymes. The distinct mechanisms of action provide strong rationale for their combined use. On the other hand, these drugs undergo extensive metabolism that determines their therapeutic potential. This review discusses how metabolism pathways and enzymes involved should be carefully considered during their combined use for therapeutic synergy.

SARS-CoV-2 Evasion of the Interferon System: Can We Restore Its Effectiveness?

Type I and III Interferons (IFNs) are the first lines of defense in microbial infections. They critically block early animal virus infection, replication, spread, and tropism to promote the adaptive immune response. Type I IFNs induce a systemic response that impacts nearly every cell in the host, while type III IFNs' susceptibility is restricted to anatomic barriers and selected immune cells. Both IFN types are critical cytokines for the antiviral response against epithelium-tropic viruses being effectors of innate immunity and regulators of the development of the adaptive immune response. Indeed, the innate antiviral immune response is essential to limit virus replication at the early stages of infection, thus reducing viral spread and pathogenesis. However, many animal viruses have evolved strategies to evade the antiviral immune response. The Coronaviridae are viruses with the largest genome among the RNA viruses. Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) caused the coronavirus disease 2019 (COVID-19) pandemic. The virus has evolved numerous strategies to contrast the IFN system immunity. We intend to describe the virus-mediated evasion of the IFN responses by going through the main phases: First, the molecular mechanisms involved; second, the role of the genetic background of IFN production during SARS-CoV-2 infection; and third, the potential novel approaches to contrast viral pathogenesis by restoring endogenous type I and III IFNs production and sensitivity at the sites of infection.

Does the use of cysteine-rich whey protein supplements (Inmunocal®) improve the health well-being of COVID-19 patients? A qualitative study

<b>Introduction:</b> In the context of SARS-CoV-2 infection, it has been proposed that oxidative stress may contribute to the management of COVID-19 severity. The impact on the well-being of patients with COVID-19 using cysteine-providing supplements has not yet been evaluated and there is a need to understand the benefits and limitations they may offer.<br /> <b>Aim:</b> The aim of this study is to understand the experiences of improved well-being with cysteine-rich whey protein supplementation (Immunocal®) in patients with COVID-19.<br /> <b>Methods:</b> A qualitative study was conducted by conducting semi-structured interviews with four participants taking Immunocal® while they had COVID-19. Participants were randomly recruited through internet networking. Ethical approval was obtained from the University ethics committee. Participants were informed of the study objectives two days in advance and consent was obtained before interviews began. We used the 16-item “Use of Immunocal supplement for COVID-19” (USIC-19) questionnaire to inquire about COVID-19 behavior (time of illness, symptoms, and severity of illness) and the experience of using the supplement during illness. Confidentiality was maintained throughout this study.<br /> <b>Results:</b> All participants presented mild discomfort such as headache, weakness, and tiredness when they had COVID-19 impacting most of them emotionally. The use of Immunocal® produced a partial improvement in all patients as only two continued to experience fatigue. Immunocal® improved the mood (50%) and physical health of the participants. In addition, participants reported that the supplement was recommended and dosed primarily by a consultant and that they did not feel hesitant to use it because of previous experiences of friends and family. The daily dosage of half of the participants was two sachets and all felt the need to consume the supplement which resulted in daily use.<br /> <b>Conclusion:</b> Following the daily dosage indications of the consultants, the participants who have consumed Inmunocal® have presented a partial improvement of the symptoms related to COVID-19, however, they feel the need to consume the supplement daily to improve their quality of life.