Proof-of-concept studies with a computationally designed Mpro inhibitor as a synergistic combination regimen alternative to Paxlovid.

As the SARS-CoV-2 virus continues to spread and mutate, it remains important to focus not only on preventing spread through vaccination but also on treating infection with direct-acting antivirals (DAA). The approval of Paxlovid, a SARS-CoV-2 main protease (Mpro) DAA, has been significant for treatment of patients. A limitation of this DAA, however, is that the antiviral component, nirmatrelvir, is rapidly metabolized and requires inclusion of a CYP450 3A4 metabolic inhibitor, ritonavir, to boost levels of the active drug. Serious drug-drug interactions can occur with Paxlovid for patients who are also taking other medications metabolized by CYP4503A4, particularly transplant or otherwise immunocompromised patients who are most at risk for SARS-CoV-2 infection and the development of severe symptoms. Developing an alternative antiviral with improved pharmacological properties is critical for treatment of these patients. By using a computational and structure-guided approach, we were able to optimize a 100 to 250 µM screening hit to a potent nanomolar inhibitor and lead compound, Mpro61. In this study, we further evaluate Mpro61 as a lead compound, starting with examination of its mode of binding to SARS-CoV-2 Mpro. In vitro pharmacological profiling established a lack of off-target effects, particularly CYP450 3A4 inhibition, as well as potential for synergy with the currently approved alternate antiviral, molnupiravir. Development and subsequent testing of a capsule formulation for oral dosing of Mpro61 in B6-K18-hACE2 mice demonstrated favorable pharmacological properties, efficacy, and synergy with molnupiravir, and complete recovery from subsequent challenge by SARS-CoV-2, establishing Mpro61 as a promising potential preclinical candidate.

Assessing antiviral treatment efficacy and risk factors for severe COVID-19 in kidney transplant recipients during the Omicron subvariant-dominant period: a retrospective study.

BACKGROUND: Kidney transplant recipients (KTRs) are at risk of severe coronavirus disease 2019 (COVID-19), and even now that Omicron subvariants have become dominant, cases of severe disease are certain to occur. The aims of this retrospective study were to evaluate the efficacy of antiviral treatment for COVID-19 and to identify risk factors for severe disease in KTRs during Omicron subvariant-dominant periods. METHODS: A total of 65 KTRs diagnosed with COVID-19 who received antiviral treatment between July 2022 and September 2023 were analyzed. Mild cases received oral molnupiravir (MP) as outpatient therapy, while moderate or worse cases received intravenous remdesivir (RDV) as inpatient therapy. In principle, mycophenolate mofetil was withdrawn and switched to everolimus. We investigated the efficacy of antiviral treatment and compared the clinical parameters of mild/moderate and severe/critical cases to identify risk factors for severe COVID-19. RESULTS: Among 65 cases, 49 were mild, 6 were moderate, 9 were severe, and 1 was of critical severity. MP was administered to 57 cases; 49 (86%) improved and 8 (14%) progressed. RDV was administered to 16 cases; 14 (87%) improved and 2 (13%) progressed. Seventeen (26%) cases required hospitalization, and none died. Comparisons of the severe/critical group (n = 10) with the mild/moderate group (n = 55) demonstrated that the severe/critical group had a significantly higher median age (64 vs. 53 years, respectively; p = 0.0252), prevalence of diabetes (70% vs. 22%, respectively; p = 0.0047) and overweight/obesity (40% vs. 11%, respectively; p = 0.0393), as well as a significantly longer median time from symptom onset to initial antiviral therapy (3 days vs. 1 day, respectively; p = 0.0026). Multivariate analysis showed that a longer time from symptom onset to initial antiviral treatment was an independent risk factor for severe COVID-19 (p = 0.0196, odds ratio 1.625, 95% confidence interval 1.081-2.441). CONCLUSION: These findings suggest that a longer time from symptom onset to initial antiviral treatment is associated with a higher risk of severe COVID-19 in KTRs. Initiating antiviral treatment as early as possible is crucial for preventing severe outcomes; this represents a valuable insight into COVID-19 management in KTRs.

A comparative study of electropolymerization and photopolymerization for the determination of molnupiravir and their application in an electrochemical sensor via computationally designed molecularly imprinted polymers.

A comparative analysis of molecularly imprinted polymers based on different synthesis techniques was performed for the recognition of molnupiravir (MOL). The polymerizations were performed with 3-thienyl boronic acid (3-TBA) as a functional monomer by electropolymerization (EP) and with guanine methacrylate (GuaM) as a functional monomer by photopolymerization (PP). Morphological and electrochemical characterizations of the developed sensors were investigated to verify the constructed sensors. Moreover, quantum chemical calculations were used to evaluate changes on the electrode surface at the molecular and electronic levels. The dynamic linear range of both designed sensors under optimized experimental conditions was found to be 7.5 × 10-12-2.5 × 10-10 M and 7.5 × 10-13-2.5 × 10-11 M for EP and PP, respectively. The effect of various interfering agents on MOL peak current was assessed for the selectivity of the study. In the presence of 100 times more interfering agents, the RSD and recovery values were determined. The RSD values of GuaM/MOL@MIP/GCE and poly(Py-co-3-PBA)/MOL@MIP/GCE sensors were found to be 1.99% and 1.72%, respectively. Furthermore, the recovery values of the MIP-based sensors were 98.18-102.69% and 98.05-103.72%, respectively. In addition, the relative selectivity coefficient (k') of the proposed sensor was evaluated, and it exhibited good selectivity for MOL with respect to the NIP sensor. The prepared sensor was successfully applied to determine MOL in commercial serum samples and capsule form. In conclusion, the developed sensors provided excellent reproducibility, repeatability, high sensitivity, and selectivity against the MOL molecule.

Detection of ac4C in human mRNA is preserved upon data reassessment.

We recently reported the distribution of N4-acetylcytidine (ac4C) in HeLa mRNA at base resolution through chemical reduction and the induction of C:T mismatches in sequencing (RedaC:T-seq). Our results contradicted an earlier report from Schwartz and colleagues utilizing a similar method termed ac4C-seq. Here, we revisit both datasets and reaffirm our findings. Through RedaC:T-seq reanalysis, we establish a low basal error rate at unmodified nucleotides that is not skewed to any specific mismatch type and a prominent increase in C:T substitutions as the dominant mismatch type in both treated wild-type replicates, with a high degree of reproducibility across replicates. In contrast, through ac4C-seq reanalysis, we uncover significant data quality issues including insufficient depth, with one wild-type replicate yielding 2.7 million reads, inconsistencies in reduction efficiencies between replicates, and an overall increase in mismatches involving thymine that could obscure ac4C detection. These analyses bolster the detection of ac4C in HeLa mRNA through RedaC:T-seq.

Molnupiravir: Mechanism of action, clinical, and translational science.

Molnupiravir is an oral prodrug of the broadly active, antiviral ribonucleoside analog N-hydroxycytidine (NHC). The primary circulating metabolite NHC is taken up into cells and phosphorylated to NHC-triphosphate (NHC-TP). NHC-TP serves as a competitive substrate for viral RNA-dependent RNA polymerase (RdRp), which results in an accumulation of errors in the viral genome, rendering virus replication incompetent. Molnupiravir has demonstrated activity against SARS-CoV-2 both clinically and preclinically and has a high barrier to development of viral resistance. Little to no molnupiravir is observed in plasma due to rapid hydrolysis to NHC. Maximum concentrations of NHC are reached at 1.5 h following administration in a fasted state. The effective half-life of NHC is 3.3 h, reflecting minimal accumulation in the plasma following twice-daily (Q12H) dosing. The terminal half-life of NHC is 20.6 h. NHC-TP exhibits a flatter profile with a lower peak-to-trough ratio compared with NHC, which supports Q12H dosing. Renal and hepatic pathways are not major routes of elimination, as NHC is primarily cleared by metabolism to uridine and cytidine, which then mix with the endogenous nucleotide pools. In a phase III study of nonhospitalized patients with COVID-19 (MOVe-OUT), 5 days of treatment with 800 mg molnupiravir Q12H significantly reduced the incidence of hospitalization or death compared with placebo. Patients treated with molnupiravir also had a greater reduction in SARS-CoV-2 viral load and improved clinical outcomes, compared with those receiving placebo. The clinical effectiveness of molnupiravir has been further demonstrated in several real-world evidence studies. Molnupiravir is currently authorized or approved in more than 25 countries.

ac4C: a fragile modification with stabilizing functions in RNA metabolism.

In recent years, concerted efforts to map and understand epitranscriptomic modifications in mRNA have unveiled new complexities in the regulation of gene expression. These studies cumulatively point to diverse functions in mRNA metabolism, spanning pre-mRNA processing, mRNA degradation, and translation. However, this emerging landscape is not without its intricacies and sources of discrepancies. Disparities in detection methodologies, divergent interpretations of functional outcomes, and the complex nature of biological systems across different cell types pose significant challenges. With a focus of N4-acetylcytidine (ac4C), this review endeavors to unravel conflicting narratives by examining the technological, biological, and methodological factors that have contributed to discrepancies and thwarted research progress. Our goal is to mitigate detection inconsistencies and establish a unified model to elucidate the contribution of ac4C to mRNA metabolism and cellular equilibrium.

Physician characteristics associated with antiviral prescriptions for older adults with COVID-19 in Japan: an observational study.

OBJECTIVES: Although guidelines recommend antiviral therapy for outpatients with COVID-19 who are at high risk of progressing to severe conditions, such as older adults, many patients do not receive appropriate treatment. Little is known, however, about the physician factors associated with the prescription of guideline-recommended antiviral therapy for patients with COVID-19. DESIGN: A cross-sectional study. SETTING: Data including outpatient visits in primary care clinics in Japan from April to August 2023. PARTICIPANTS: We analysed 30 953 outpatients aged ≥65 years treated with COVID-19 (mean (SD) age, 75.0 (7.6) years; 17 652 women (57.0%)) in 1394 primary care clinics. OUTCOME MEASURES: The primary outcome was the prescription of guideline-recommended antivirals (ie, nirmatrelvir-ritonavir or molnupiravir), adjusted for patient characteristics, months of visits and regions. RESULTS: Antiviral prescriptions were concentrated among a small proportion of physicians; for example, the top 10% of physicians that had the largest number of nirmatrelvir-ritonavir prescriptions accounted for 92.4% of all nirmatrelvir-ritonavir prescriptions. After adjusting for potential confounders, physicians with higher patient volumes were more likely to prescribe guideline-recommended antivirals to their patients (adjusted OR (aOR) for high vs low volume, 1.76; 95% CI 1.31 to 2.38; adjusted p<0.001). We found no evidence that the likelihood of guideline-recommended antiviral prescription differed based on physicians' gender (aOR for women vs men, 1.24; 95% CI 0.88 to 1.74; adjusted p=0.48) or age (aOR for 45-59 vs <45 years, 1.16; 95% CI 0.87 to 1.54; adjusted p=0.48; aOR for ≥60 vs <45 years, 0.88; 95% CI 0.66 to 1.16; adjusted p=0.48). These patterns were similar when examining nirmatrelvir-ritonavir and molnupiravir separately. CONCLUSIONS: Our findings suggest that provider-level factors, such as the clinical experience of treating the patients with COVID-19, play an important role in the appropriate prescription of antiviral medications for COVID-19 in the primary care setting.

New conjugates based on N4-hydroxycytidine with more potent antiviral efficacy in vitro than EIDD-2801 against SARS-CoV-2 and other human coronaviruses.

The spread of COVID-19 continues due to genetic variation in SARS-CoV-2. Highly mutated variants of SARS-CoV-2 have an increased transmissibility and immune evasion. Due to the emergence of various new variants of the virus, there is an urgent need to develop broadly effective specific drugs for therapeutic strategies for the prevention and treatment of COVID-19. Molnupiravir (EIDD-2801, MK-4482), is an orally bioavailable ribonucleoside analogue of ß-D-N4-hydroxycytidine (NHC), has demonstrated efficacy against SARS-CoV-2 and was recently approved for COVID-19 treatment. To improve antiviral potency of NHC, we developed a panel of NHC conjugates with lipophilic vectors and ester derivatives with amino- and carboxylic-acids. Most of the synthesized compounds had comparable or higher (2-20 times) antiviral activity than EIDD-2801, against different lineages of SARS-CoV-2, MERS-CoV, seasonal coronaviruses OC43 and 229E, as well as bovine coronavirus. For further studies, we assessed the most promising compound in terms of activity, simplicity and cost of synthesis - NHC conjugate with phenylpropionic acid (SN_9). SN_9 has shown high efficacy in prophylactic, therapeutic and transmission models of COVID-19 infection in hamsters. Importantly, SN_9 profoundly inhibited virus replication in the lower respiratory tract of hamsters and transgenic mice infected with the Omicron sublineages XBB.1.9.1, XBB.1.16 and EG.5.1.1. These data indicate that SN_9 represents a promising antiviral drug candidate for COVID-19 treatment, and NHC modification strategies deserve further investigation as an approach to develop prodrugs against various coronaviruses.

The host-targeted antiviral drug Zapnometinib exhibits a high barrier to the development of SARS-CoV-2 resistance.

Host targeting antiviral drugs (HTA) are directed against cellular mechanisms which can be exploited by viruses. These mechanisms are essential for viral replication, because missing functions cannot be compensated by the virus. However, this assumption needs experimental proof. Here we compared the HTA Zapnometinib (ZMN), with direct acting antivirals (DAA) (Remdesivir (RDV), Molnupiravir (MPV), Nirmatrelvir (NTV), Ritonavir (RTV), Paxlovid PAX)), in terms of their potency to induce reduced drug susceptibilities in SARS-CoV-2. During serial passage of δ-B1.617.2 adaptation to all DAAs occurred, while the inhibitory capacity of ZMN was not altered. Known single nucleotide polymorphisms (SNPs) responsible for partial resistances were found for RDV, NTV and PAX. Additionally, the high mutagenic potential of MPV was confirmed and decreased drug efficacies were found for the first time. Reduced DAA efficacy did not alter the inhibitory potential of ZMN. These results show that ZMN confers a high barrier towards the development of viral resistance and has the potential to act against partially DAA-insensitive viruses.

ß-D-N4-hydroxycytidine (NHC, EIDD-1931) inhibits chikungunya virus replication in mosquito cells and ex vivo Aedes aegypti guts, but not when ingested during blood-feeding.

Chikungunya virus (CHIKV) is a mosquito-borne virus transmitted by Aedes mosquitoes. While there are no antiviral therapies currently available to treat CHIKV infections, several licensed oral drugs have shown significant anti-CHIKV activity in cells and in mouse models. However, the efficacy in mosquitoes has not yet been assessed. Such cross-species antiviral activity could be favorable, since virus inhibition in the mosquito vector might prevent further transmission to vertebrate hosts. Here, we explored the antiviral effect of ß-d-N4-hydroxycytidine (NHC, EIDD-1931), the active metabolite of molnupiravir, on CHIKV replication in Aedes aegypti mosquitoes. Antiviral assays in mosquito cells and in ex vivo cultured mosquito guts showed that NHC had significant antiviral activity against CHIKV. Exposure to a clinically relevant concentration of NHC did not affect Ae. aegypti lifespan when delivered via a bloodmeal, but it slightly reduced the number of eggs developed in the ovaries. When mosquitoes were exposed to a blood meal containing both CHIKV and NHC, the compound did not significantly reduce virus infection and dissemination in the mosquitoes. This was confirmed by modelling and could be explained by pharmacokinetic analysis, which revealed that by 6 h post-blood-feeding, 90% of NHC had been cleared from the mosquito bodies. Our data show that NHC inhibited CHIKV replication in mosquito cells and gut tissue, but not in vivo when mosquitoes were provided with a CHIKV-infectious bloodmeal spiked with NHC. The pipeline presented in this study offers a suitable approach to identify anti-arboviral drugs that may impede replication in mosquitoes.

GANSamples-ac4C: Enhancing ac4C site prediction via generative adversarial networks and transfer learning.

RNA modification, N4-acetylcytidine (ac4C), is enzymatically catalyzed by N-acetyltransferase 10 (NAT10) and plays an essential role across tRNA, rRNA, and mRNA. It influences various cellular functions, including mRNA stability and rRNA biosynthesis. Wet-lab detection of ac4C modification sites is highly resource-intensive and costly. Therefore, various machine learning and deep learning techniques have been employed for computational detection of ac4C modification sites. The known ac4C modification sites are limited for training an accurate and stable prediction model. This study introduces GANSamples-ac4C, a novel framework that synergizes transfer learning and generative adversarial network (GAN) to generate synthetic RNA sequences to train a better ac4C modification site prediction model. Comparative analysis reveals that GANSamples-ac4C outperforms existing state-of-the-art methods in identifying ac4C sites. Moreover, our result underscores the potential of synthetic data in mitigating the issue of data scarcity for biological sequence prediction tasks. Another major advantage of GANSamples-ac4C is its interpretable decision logic. Multi-faceted interpretability analyses detect key regions in the ac4C sequences influencing the discriminating decision between positive and negative samples, a pronounced enrichment of G in this region, and ac4C-associated motifs. These findings may offer novel insights for ac4C research. The GANSamples-ac4C framework and its source code are publicly accessible at http://www.healthinformaticslab.org/supp/.

Comparison of azvudine, molnupiravir, and nirmatrelvir/ritonavir in adult patients with mild-to-moderate COVID-19: a retrospective cohort study.

This study aimed to explore the effectiveness and safety of azvudine, nirmatrelvir/ritonavir, and molnupiravir in adult patients with mild-to-moderate COVID-19. This retrospective cohort study included patients with mild-to-moderate COVID-19 (asymptomatic, mild, and common types) at the First Hospital of Changsha (Hunan Province, China) between March and November 2022. Eligible patients were classified into the azvudine, nirmatrelvir/ritonavir, or molnupiravir groups according to the antiviral agents they received. The outcomes were the times to nucleic acid negative conversion (NANC). This study included 157 patients treated with azvudine (n = 66), molnupiravir (n = 66), or nirmatrelvir/ritonavir (n = 25). There were no statistically significant differences in the time from diagnosis to NANC among the azvudine, molnupiravir, and nirmatrelvir/ritonavir groups [median, 9 (95% CI 9-11) vs. 11 (95% CI 10-12) vs. 9 (95% CI 8-12) days, P = 0.15], time from administration to NANC [median, 9 (95% CI 8-10) vs. 10 (95% CI 9.48-11) vs. 8.708 (95% CI 7.51-11) days, P = 0.50], or hospital stay [median, 11 (95% CI 11-13) vs. 13 (95% CI 12-14) vs. 12 (95% CI 10-14) days, P = 0.14], even after adjustment for sex, age, COVID-19 type, comorbidities, Ct level, time from diagnosis to antiviral treatment, and number of symptoms. The cumulative NANC rates in the azvudine, molnupiravir, and nirmatrelvir/ritonavir groups were 15.2%/12.3%/16.0% at day 5 (P = 0.858), 34.8%/21.5%/32.0% at day 7 (P = 0.226), 66.7%/52.3%/60.0% at 10 days (P = 0.246), and 86.4%/86.2%/80.0% at day 14 (P = 0.721). No serious adverse events were reported. Azvudine may be comparable to nirmatrelvir/ritonavir and molnupiravir in adult patients with mild-to-moderate COVID-19 regarding time to NANC, hospital stay, and AEs.

N4-acetylcytidine (ac4C) promotes mRNA localization to stress granules.

Stress granules are an integral part of the stress response that are formed from non-translating mRNAs aggregated with proteins. While much is known about stress granules, the factors that drive their mRNA localization are incompletely described. Modification of mRNA can alter the properties of the nucleobases and affect processes such as translation, splicing and localization of individual transcripts. Here, we show that the RNA modification N4-acetylcytidine (ac4C) on mRNA associates with transcripts enriched in stress granules and that stress granule localized transcripts with ac4C are specifically translationally regulated. We also show that ac4C on mRNA can mediate localization of the protein NOP58 to stress granules. Our results suggest that acetylation of mRNA regulates localization of both stress-sensitive transcripts and RNA-binding proteins to stress granules and adds to our understanding of the molecular mechanisms responsible for stress granule formation.

Randomized controlled trial of molnupiravir SARS-CoV-2 viral and antibody response in at-risk adult outpatients.

Viral clearance, antibody response and the mutagenic effect of molnupiravir has not been elucidated in at-risk populations. Non-hospitalised participants within 5 days of SARS-CoV-2 symptoms randomised to receive molnupiravir (n = 253) or Usual Care (n = 324) were recruited to study viral and antibody dynamics and the effect of molnupiravir on viral whole genome sequence from 1437 viral genomes. Molnupiravir accelerates viral load decline, but virus is detectable by Day 5 in most cases. At Day 14 (9 days post-treatment), molnupiravir is associated with significantly higher viral persistence and significantly lower anti-SARS-CoV-2 spike antibody titres compared to Usual Care. Serial sequencing reveals increased mutagenesis with molnupiravir treatment. Persistence of detectable viral RNA at Day 14 in the molnupiravir group is associated with higher transition mutations following treatment cessation. Viral viability at Day 14 is similar in both groups with post-molnupiravir treated samples cultured up to 9 days post cessation of treatment. The current 5-day molnupiravir course is too short. Longer courses should be tested to reduce the risk of potentially transmissible molnupiravir-mutated variants being generated. Trial registration: ISRCTN30448031.

Respiratory virus coinfections during the COVID-19 pandemic: epidemiologic analysis and clinical outcomes from the Phase 2/3 molnupiravir trial (MOVe-OUT).

This exploratory post hoc analysis assessed the incidence of respiratory viral coinfections and their impact on clinical outcomes in non-hospitalized adults with mild-to-moderate coronavirus disease-2019 (COVID-19) treated with molnupiravir versus placebo for 5 days in the Phase 2/3 MOVe-OUT trial (NCT04575597), which took place in October 2020 to January 2021 (Phase 2, n = 302) and May 2021 to October 2021 (Phase 3, n = 1,433). Among 1,735 total randomized participants, 1,674 had a baseline respiratory pathogen panel (NxTAG Respiratory Pathogen Panel for the Luminex MAGPIX instrument) performed and 69 (4.1%) were coinfected with at least one additional respiratory viral pathogen. Human rhinovirus/enterovirus (39/69, 56.5%) was the most common coinfection detected at baseline. In the modified intention-to-treat population, two participants with coinfecting respiratory RNA viruses were hospitalized and received respiratory interventions through Day 29, and none died; one participant in the molnupiravir group was coinfected with human rhinovirus/enterovirus, and one participant in the placebo group was coinfected with human metapneumovirus. Hospitalization or death occurred in 6.2% and 9.0% of non-coinfected participants in the molnupiravir versus placebo group, respectively, and over 90% did not require respiratory interventions. Most coinfecting respiratory RNA viruses detected at baseline were not detected at the end of therapy in both the molnupiravir and placebo groups. In summary, participants coinfected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and another respiratory RNA virus were not more likely to be hospitalized or die, or require respiratory interventions, compared to participants who were not coinfected with another respiratory RNA virus at baseline in both groups. IMPORTANCE: Respiratory viral coinfections are known to occur with coronavirus disease-2019 (COVID-19). In a cohort of non-hospitalized adults with mild-to-moderate COVID-19 treated with molnupiravir versus placebo in the MOVe-OUT trial during October 2020 to October 2021, 4.1% of participants had a documented viral coinfection; human rhinovirus/enterovirus was the most common pathogen detected with the NxTAG Respiratory Pathogen Panel assay. Participants who had a coinfection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and another respiratory RNA virus were not more likely to have worse clinical outcomes compared to those participants without a viral coinfection, and many coinfecting respiratory RNA viruses were no longer detected at the end of the 5-day treatment period in both groups.

Molnupiravir inhibits human norovirus and rotavirus replication in 3D human intestinal enteroids.

Human norovirus (HuNoV) and human rotavirus (HRV) are the leading causes of gastrointestinal diarrhea. There are no approved antivirals and rotavirus vaccines are insufficient to cease HRV associated mortality. Furthermore, treatment of chronically infected immunocompromised patients is limited to off-label compassionate use of repurposed antivirals with limited efficacy, highlighting the urgent need of potent and specific antivirals for HuNoV and HRV. Recently, a major breakthrough in the in vitro cultivation of HuNoV and HRV derived from the use of human intestinal enteroids (HIEs). The replication of multiple circulating HuNoV and HRV genotypes can finally be studied and both in the same non-transformed and physiologically relevant model. Activity of previously described anti-norovirus or anti-rotavirus drugs, such as 2'-C-methylcytidine (2CMC), 7-deaza-2'-C-methyladenosine (7DMA), nitazoxanide, favipiravir and dasabuvir, was assessed against clinically relevant human genotypes using 3D-HIEs. 2CMC showed the best activity against HuNoV GII.4, while 7DMA was the most potent antiviral against HRV. We identified the anti-norovirus and -rotavirus activity of molnupiravir and its active metabolite, N4-hydroxycytidine (NHC), a broad-spectrum antiviral used to treat coronavirus disease 2019 (COVID-19). Molnupiravir and NHC inhibit HuNoV GII.4, HRV G1P[8], G2P[4] and G4P[6] in 3D-HIEs with high selectivity and show a potency comparable to 2CMC against HuNoV. Moreover, molnupiravir and NHC block HRV viroplasm formation, but do not alter its size or subcellular localization. Taken together, molnupiravir inhibits both HuNoV and HRV replication, suggesting that the drug could be a candidate for the treatment of patients chronically infected with either one of these diarrhea causing viruses.

Determining and Comparing the Real-World Effectiveness of Molnupiravir and Nirmatrelvir-Ritonavir in Patients Hospitalized With COVID-19.

BACKGROUND: Current guidelines recommend using nirmatrelvir-ritonavir for coronavirus disease 2019 (COVID-19) treatment, but its potential drug interactions and contraindications limit its applicability in certain categories of patients. The aim of the study was to evaluate the real-world effectiveness of molnupiravir and nirmatrelvir-ritonavir in managing COVID-19 among hospitalized patients. METHODS: We conducted a retrospective cohort study among hospitalized COVID-19 patients who received molnupiravir or nirmatrelvir-ritonavir and did not require baseline supplemental oxygen from February 2022 to January 2023. We compared the effectiveness of molnupiravir and nirmatrelvir-ritonavir with a focus on disease progression. RESULTS: The study included 401 high-risk, hospitalized adult COVID-19 patients who received molnupiravir or nirmatrelvir-ritonavir. No significant difference was found in disease progression, the composite outcome of disease progression (4.0% vs. 1.4%, P = 0.782), and O2 supplementation via nasal prong (21.8% vs. 14.8%, P = 0.115) between the patients treated with molnupiravir and those treated with nirmatrelvir-ritonavir. This finding was similar after 1:1 propensity-score matching. In the multivariate analysis, molnupiravir treatment was not significantly associated with progression to severe disease. CONCLUSION: In conclusion, our findings suggest that similar to nirmatrelvir-ritonavir, molnupiravir has a distinct potential role in COVID-19 treatment, transcending its current perceived status as only a secondary option.

Protection-Free, Two-step Synthesis of C5-C Functionalized Pyrimidine Nucleosides.

A simple, reliable, and efficient method for the gram-scale chemical synthesis of pyrimidine nucleosides functionalized with C5-carboxyl, nitrile, ester, amide, or amidine, starting from unprotected uridine and cytidine, is described. The protocol involves the synthesis of 5-trifluoromethyluridine and 5-trifluoromethylcytidine with Langlois reagent (CF3 SO2 Na) in the presence of tert-butyl hydroperoxide and subsequent transformation of the CF3 group to the C5-C 'carbon substituents' under alkaline conditions. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Synthesis and characterization of 5-trifluoromethyluridine (5-CF3 U) and 5-trifluoromethylcytidine (5-CF3 C) Basic Protocol 2: Conversion of 5-CF3 U and 5-CF3 C to several C5-substituted ribonucleosides.