Being Physically Active for a Long-Standing Mitigates Inflammaging Progression in Older Adults during the COVID-19 Pandemic (preprint)

Background: Here, we investigated the inflammaging and physical performance in older adults before and after the COVID-19 pandemic. Methods: Women(n=18) and men(n=7) older were evaluated before the COVID-19 pandemic(PRE), 12 months after the lockdown(POST), and 10 months after resuming exercise training(POS-TR). Physical tests [gait speed(GS) and timed-up-and-go(TUG)]; muscle strength (handgrip-HG), and serum cytokine levels were assessed. Results: The older women showed higher GS and TUG at POST than PRE and POST-TR, besides lower HG at POST-TR than PRE, whereas older men exhibited lower HG at POST and POST-TR than PRE. Both groups presented (1)lower IL-10 and IL-12p70 values in contrast to higher IL-6/IL-10 and IL-8/IL-10 ratios at POST than PRE; (2)higher IL-10 values and lower IL-8/IL-10 ratio at POST-TR than POST; (3)higher IL-12p70/IL-10 ratio at POST-TR than PRE and POST. Particularly older women showed: (4)lower IL-6 values at POST and POST-TR than PRE; (5)lower IL-8 and IL-10 values at POST-TR than POST; (6)and higher TNF-α/IL-10 and IFN-γ/IL-10 ratios at POST than PRE and POST-TR. Significant correlations between the variables were found in both groups. Conclusion: During the COVID-19 pandemic, detraining and resumption of exercise training promoted distinct alterations in physical capacity and inflammaging among older women and older men population.

Taiwan Chingguan Yihau (NRICM101) prevents kainic acid-induced seizures in rats by modulating neuroinflammation and the glutamatergic system (preprint)

Taiwan Chingguan Yihau (NRICM101) is a Traditional Chinese medicine (TCM) formula used to treat coronavirus disease 2019; however, its impact on epilepsy has not been revealed. Therefore, the present study evaluated the anti-epileptogenic effect of orally administered NRICM101 on kainic acid (KA)-induced seizures in rats and investigated its possible mechanisms of action. Sprague‒Dawley rats were administered NRICM101 (300 mg/kg) by oral gavage for 7 consecutive days before receiving an intraperitoneal injection of KA (15 mg/kg). NRICM101 considerably reduced the seizure behavior and electroencephalographic seizures induced by KA in rats. NRICM101 also significantly decreased the neuronal loss and glutamate increase and increased GLAST, GLT-1, GAD67, GDH and GS levels in the cortex and hippocampus of KA-treated rats. In addition, NRICM101 significantly suppressed astrogliosis (as determined by decreased GFAP expression); neuroinflammatory signaling (as determined by reduced HMGB1, TLR-4, IL-1β, IL-1R, IL-6, p-JAK2, p-STAT3, TNF-α, TNFR1 and p-IκB levels, and increased cytosolic p65-NFκB levels); and necroptosis (as determined by decreased p-RIPK3 and p-MLKL levels) in the cortex and hippocampus of KA-treated rats. The effects of NRICM101 were similar to those of carbamazepine, a well-recognized antiseizure drug. Furthermore, no toxic effects of NRICM101 on the liver and kidney were observed in NRICM101-treated rats. The results indicate that NRICM101 has antiepileptogenic and neuroprotective effects through the suppression of the inflammatory cues (HMGB1/TLR4, Il-1β/IL-1R1, IL-6/p-JAK2/p-STAT3, and TNF-α/TNFR1/NF-κB) and necroptosis signaling pathways (TNF-α/TNFR1/RIP3/MLKL) associated with glutamate level regulation in the brain and is innocuous. Our findings highlight the promising role of NRICM101 in the management of epilepsy.

Discovery of GS-5245 (Obeldesivir), an Oral Prodrug of Nucleoside GS-441524 that Exhibits Antiviral Efficacy in SARS-CoV-2 Infected African Green Monkeys (preprint)

Remdesivir 1 is an amidate prodrug that releases the monophosphate of nucleoside GS-441524 (2) into lung cells thereby forming the bioactive triphosphate 2-NTP. 2-NTP, an analog of ATP, inhibits the SARS-CoV-2 RNA-dependent RNA polymerase replication and transcription of viral RNA. Strong clinical results for 1 have prompted interest in oral approaches to generate 2-NTP. Here we describe the discovery of a 5'-isobutyryl ester prodrug of 2 (GS-5245, Obeldesivir, 3) that has low cellular cytotoxicity and three to seven-fold improved oral delivery of 2 in monkeys. Prodrug 3 is cleaved pre-systemically to provide high systemic exposures of 2 that overcome its less efficient metabolism to 2-NTP leading to strong SARS-CoV-2 antiviral efficacy in an African green monkey infection model. Exposure-based SARS-CoV-2 efficacy relationships resulted in an estimated clinical dose of 350-400 mg twice-daily. Importantly, all SARS-CoV-2 variants remain susceptible to 2 which supports development of 3 as a promising COVID-19 treatment.

Long-term outcomes of COVID-19 infection in children and young people: a systematic review and meta-analysis (preprint)

Background Children and young people (CYP) may experience prolonged symptoms following COVID-19, commonly termed "Long-COVID". The nature of this in CYP is unclear, as are the sequalae of acute COVID-19. We aimed to systematically synthesise evidence of the long-term outcomes of COVID-19 in CYP. Methods 13 databases were searched until January 2022. Inclusion criteria: Observational studies reporting outcomes occurring four-weeks or more after COVID-19 in children <18 years old. Exclusion criteria: Outcomes of Paediatric Inflammatory Multisystem Syndrome. Title, abstract and full text screening were conducted independently by two reviewers. Data extraction and risk of bias assessment was by one reviewer with independent verification. Critical appraisal tools appropriate for study type were employed. Results were narratively synthesised with meta-analysis to generate summary estimates of risk of prolonged symptoms in CYP. Findings 94 studies were included. 66 recruited from hospital settings, 8 recruited solely from community settings. >100 symptoms were reported, the most common being fatigue, headache and cognitive symptoms. Summary estimates of risk of prolonged symptoms were higher for hospital samples (31.2%, 95% CI 20.3% to 43.2%) than for community samples (4.6%, 95% CI 3.4% to 5.8). Sequalae including stroke, type-1 diabetes, Guillan-Barre syndrome, and persistent radiological or blood test abnormalities have been reported in CYP following COVID-19. Most studies reporting these are case reports / case series and quality of evidence is low. Interpretation Prolonged symptoms following COVID-19 in children are variable and multi-system. Rates in community samples are lower than hospital. There is limited data on other sequalae in CYP. Heterogeneity in diagnosis of COVID-19, symptom classification, assessment method and duration of follow-up made synthesis less secure. Funding HT, CB and GS have National Institute for Health and Care Research fellowships. RB, CM and VW are supported by the NIHR West Midlands Applied Research Collaboration. CM Is supported by the NIHR School for Primary Care Research Research in context panel Evidence before this study At the time of writing and to the best of our knowledge, the protocol for this systematic review was a novel endeavour to summarise the longer-term effects of COVID-19 in children and young people (CYP). At least three systematic reviews have since been published, summarising the symptom profile and prevalence of Long-COVID in CYP, but prevalence estimates vary widely and the evidence base remains uncertain. In addition, there is very limited information on other sequalae of COVID-19 in this population group. We searched thirteen electronic databases (MEDLINE, EMBASE, AMED, HMIC, CINAHLPlus, PsycINFO, Web of Science (Science Citation and Social Science Citation indicies), ASSIA, WHO COVID-19: Global literature on coronavirus disease, Cochrane COVID-19 study register, ProQuest Coronavirus research database, NDLTD and OpenGrey) up to January 2022 for any empirical study including search terms pertaining to longer term symptoms of COVID-19 in CYP (<18 years old). The quality of the studies was mixed. Results were analysed narratively for each objective, and random effects meta-analyses conducted to estimate risk of prolonged symptoms in CYP who have had COVID-19. Added value of this study This review adds to the evidence of the heterogeneity of prolonged symptoms following COVID-19 in CYP but importantly, stratifies risk of this by recruitment setting. We also synthesise evidence on broader sequalae of the acute infection in this CYP and longer-term effects in CYP with pre-existing conditions, which have not been considered in previous reviews. We purposefully included case studies and case series, to capture emerging patterns of outcomes, which may well be important in a novel condition with a rapidly increasing volume of publications. To our knowledge, this systematic review and meta-analysis is the most comprehensive to date. Implications of all the available evidence This review adds to the evidence that a substantial proportion of CYP do experience effects of COVID-19 that last longer than four-weeks, with the most frequently reported prolonged symptoms being fatigue, headache and cognitive symptoms. The proportion of CYP developing prolonged symptoms in children recruited from community setting was low, although this may translate to a large number of affected CYP at population level. There is a paucity of controlled studies and this limits confidence that prolonged symptoms are attributable to COVID-19. Sequalae including stroke, type-1 diabetes, Guillan-Barre syndrome, and persistent radiological or blood test abnormalities have been reported in CYP following COVID-19 but most studies reporting these are case reports / case series and quality of evidence is low. To develop treatment plans and interventions for affected CYP, further studies are needed to better characterise this condition and understand its impact on the lives of CYP and their families and communities. These should ideally recruit from community settings, include population-based control groups and consider using standardised definitions and outcome measures where possible.

Genome charaterization based on the Spike-614 and NS8-84 loci of SARS-CoV-2 reveals two major onsets of the COVID-19 pandemic (preprint)

The global COVID-19 pandemic has lasted for three years since its outbreak, however its origin is still unknown. Here, we analyzed the genotypes of 3.14 million SARS-CoV-2 genomes based on the amino acid 614 of the Spke (S) and the amino acid 48 of NS8 (nonstructural protein 8), and identified 16 linkage haplotypes. The GL haplotype (S_614G and NS8_48L) was the major haplotype driving the global pandemic and accounted for 99.2% of the sequenced genomes, while the DL haplotype (S_614D and NS8_48L) caused the pandemic in China in the spring of 2020 and accounted for approximately 60% of the genomes in China and 0.45% of the global genomes. The GS (S_614G and NS8_48S), DS (S_614D and NS8_48S) and NS (S_614N and NS8_48S) haplotypes accounted for 0.26%, 0.06%, and 0.0067% of the genomes, respectively. The main evolutionary trajectory of SARS-CoV-2 is DS[->]DL[->]GL, whereas the other haplotypes are minor byproducts in the evolution. Surprisingly, the newest haplotype GL had the oldest time of most recent common ancestor (tMRCA), which was May 1 2019 by mean, while the oldest haplotype had the newest tMRCA with a mean of October 17, indicating that the ancestral strains that gave birth to GL had been extinct and replaced by the more adapted newcomer at the place of its origin, just like the sequential rise and fall of the delta and omicron variants. However, they arrived and evolved into toxic strains and ignited a pandemic in China where the GL strains did not exist at the end of 2019. The GL strains had spread all over the world before they were discovered, and ignited the global pandemic, which had not been noticed until the pandemic was declared in China. However, the GL haplotype had little influence in China during the early phase of the pandemic due to its late arrival as well as the strict transmission controls in China. Therefore, we propose two major onsets of the COVID-19 pandemic, one was mainly driven by the haplotype DL in China, the other was driven by the haplotype GL globally.

Combination of the parent analogue of Remdesivir (GS-441524) and Molnupiravir results in a markedly potent antiviral effect in SARS-CoV-2 infected Syrian hamsters (preprint)

Remdesivir was the first drug to be approved for the treatment of severe COVID-19; followed by molnupiravir (another prodrug of a nucleoside analogue) and the protease inhibitor nirmatrelvir. Combination of antiviral drugs may result in improved potency and help to avoid or delay the development of resistant variants. We set out to explore the combined antiviral potency of GS-441524 (the parent nucleoside of remdesivir) and molnupiravir against SARS-CoV-2. In SARS-CoV-2 (BA.5) infected A549-Dual hACE2-TMPRSS2 cells, the combination resulted in an overall additive antiviral effect with a synergism at certain concentrations. Next, the combined effect was explored in Syrian hamsters infected with SARS-CoV-2 (Beta, B.1.351); treatment was started at the time of infection and continued twice daily for four consecutive days. At 4 day 4 post-infection, GS-441524 (50 mg/kg, oral BID) and molnupiravir (150 mg/kg, oral BID) as monotherapy reduced infectious viral loads by 0.5 and 1.6 log10, respectively, compared to the vehicle control. When GS-441524 (50 mg/kg, BID) and molnupiravir (150 mg/kg, BID) were combined, infectious virus was no longer detectable in the lungs of 7 out of 10 of the treated hamsters (4.0 log10 reduction) and titers in the other animals were reduced by ~2 log10. The combined antiviral activity of molnupiravir which acts by inducing lethal mutagenesis and GS-441524, which acts as a chain termination appears to be highly effective in reducing SARS-CoV-2 replication/infectivity. The unexpected potent antiviral effect of the combination warrants further exploration as a potential treatment for COVID-19.

Efficacy of ultra-short, response-guided sofosbuvir and daclatasvir therapy for Hepatitis C: a single arm mechanistic pilot study (preprint)

ABSTRACT Background WHO has called for research into predictive factors for selecting persons who could be successfully treated with shorter durations of direct acting antiviral (DAA) therapy for Hepatitis C. We evaluated early virological response as a means of shortening treatment and explored host, viral and pharmacokinetic contributors to treatment outcome. Methods Duration of sofosbuvir and daclatasvir (SOF/DCV) was determined according to day 2 (D2) virologic response for HCV genotype (gt) 1- or 6-infected adults in Vietnam with mild liver disease. Participants received 4 or 8 weeks treatment according to whether D2 HCV RNA was above or below 500 IU/ml (standard duration is 12 weeks). Primary endpoint was sustained virological response (SVR12). Those failing therapy were retreated with 12 weeks SOF/DCV. Host IFNL4 genotype and viral sequencing was performed at baseline, with repeat viral sequencing if virological rebound was observed. Levels of SOF, its inactive metabolite GS-331007 and DCV were measured on day 0 and 28. Results Of 52 adults enrolled, 34 received 4 weeks SOF/DCV, 17 got 8 weeks and one withdrew. SVR12 was achieved in 21/34 (62%) treated for 4 weeks, and 17/17 (100%) treated for 8 weeks. Overall 38/51 (75%) were cured with first-line treatment (mean duration 37 days). Despite a high prevalence of putative NS5A-inhibitor resistance associated substitutions (RAS), all first-line treatment failures cured after retreatment (13/13). We found no evidence treatment failure was associated with host IFNL4 genotype, viral subtype, baseline RAS or DCV levels. SOF metabolite levels were higher in those failing 4-week therapy. Conclusions Shortened SOF/DCV therapy, with retreatment if needed, reduces DAA use while maintaining high cure rates. D2 virologic response alone does not adequately predict SVR12 with 4 weeks treatment. Funding Funded by the Medical Research Council (grant MR/P025064/1) and The Global Challenges Research Fund (Wellcome Trust Grant 206/296/Z/17/Z).) Clinical trial number ISRCTN17100273

Remdesivir Treatment alters Circulating MicroRNA Profile in Coronavirus Disease 2019 (COVID-19) Patients (preprint)

Coronavirus disease 2019 (COVID-19), a serious infectious disease caused by the newly discovered Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), represents a significant global health crisis nowadays. Although no specific antiviral drug has been proven to be fully effective against COVID-19, Remdesivir (GS-5734), a nucleoside analogue prodrug, showed beneficial effects upon treating severe hospitalized COVID-19 cases. The molecular mechanism underlying this beneficial therapeutic effect is still vague. In this study, we assessed the effect of Remdesivir treatment on the signature of circulating miRNAs in the plasma of COVID-19 patients. MiRCURY LNA miRNome qPCR Panels were used to characterize the miRNA signature. Individual quantitative real-time RT-PCR (qRT-PCR) was performed to confirm the outcome of miRCURY LNA miRNome qPCR Panels. Our results revealed that Remdesivir can restore the expression of a panel of miRNAs being upregulated in COVID-19 patients into levels comparable to those exhibited by healthy donors. Bioinformatics analysis revealed that these miRNAs are involved in diverse biological processes such as Transforming growth factor beta (TGF-β) signalling pathway, Hippo signaling, P53 signalling and Rap1 signaling pathway. On the other hand, 3 miRNAs (hsa-miR-7-5p, hsa-miR-10b-5p, hsa-miR-130b-3p) were upregulated in patients only following Remdesivir treatment or in naturally remitted patients. These upregulated miRNAs could serve as biomarkers of COVID-19 remission. The output of this study highlights that Remedisivir therapeutic potential involves miRNA-regulated molecular mechanisms.

Remdesivir and GS-441524 retain antiviral activity against Delta, Omicron, and other emergent SARS-CoV-2 variants (preprint)

Genetic variation of SARS-CoV-2 has resulted in the emergence and rapid spread of multiple variants throughout the pandemic, of which Omicron is currently the predominant variant circulating worldwide. SARS-CoV-2 variants of concern or interest (VOC/VOI) have evidence of increased viral transmission, disease severity, or decreased effectiveness of vaccines and neutralizing antibodies. Remdesivir (RDV, VEKLURY ® ) is a nucleoside analog prodrug and the first FDA-approved antiviral treatment of COVID-19. Here we present a comprehensive antiviral activity assessment of RDV and its parent nucleoside, GS-441524, against 10 current and former SARS-CoV-2 VOC/VOI clinical isolates by nucleoprotein ELISA and plaque reduction assay. Delta and Omicron variants remained susceptible to RDV and GS-441524, with EC 50 values 0.31 to 0.62-fold of those observed against the ancestral WA1 isolate. All other tested variants exhibited EC 50 values ranging from 0.15 to 2.3-fold of the observed EC 50 values against WA1. Analysis of nearly 6 million publicly available variant isolate sequences confirmed that Nsp12, the RNA-dependent RNA polymerase (RdRp) target of RDV and GS-441524, is highly conserved across variants with only 2 prevalent changes (P323L and G671S). Using recombinant viruses, both RDV and GS-441524 retained potency against all viruses containing frequent variant substitutions or their combination. Taken together, these results highlight the conserved nature of SARS-CoV-2 Nsp12 and provide evidence of sustained SARS-CoV-2 antiviral activity of RDV and GS-441524 across the tested variants. The observed pan-variant activity of RDV supports its continued use for the treatment of COVID-19 regardless of the SARS-CoV-2 variant.

Preclinical Pharmacokinetics and In Vitro Properties of GS-441524, A Potential Oral Drug Candidate for COVID-19 Treatment (preprint)

Preclinical pharmacokinetics (PK) and in vitro ADME properties of GS-441524, a potential oral agent for the treatment of Covid-19, were studied. GS-441524 was stable in vitro in liver microsomes, cytosols, and hepatocytes of mice, rats, monkeys, dogs, and humans. The plasma free fractions of GS-441524 were 62-78% across all studied species. The in vitro transporter study results showed that GS-441524 was a substrate of MDR1, BCRP, CNT3, ENT1, and ENT2; but not a substrate of CNT1, CNT2, and ENT4. GS-441524 had a low to moderate plasma clearance (CLp), ranging from 4.1 mL/min/kg in dogs to 26 mL/min/kg in mice; the steady state volume distribution (Vdss) ranged from 0.9 L/kg in dogs to 2.2 L/kg in mice after IV administration. Urinary excretion appeared to be the major elimination process for GS-441524. Following oral administration, the oral bioavailability was 8.3% in monkeys, 33% in rats, 39% in mice, and 85% in dogs. The PK and ADME properties of GS-441524 support its further development as an oral drug candidate.

Distinct genetic determinants and mechanisms of SARS-CoV-2 resistance to remdesivir (preprint)

The nucleoside analog remdesivir (RDV) is an FDA-approved antiviral for the treatment of SARS-CoV-2 infections, and as such it is critical to understand potential genetic determinants and barriers to RDV resistance. In this study, SARS-CoV-2 was subjected to 13 passages in cell culture with increasing concentrations of GS-441524, the parent nucleoside of RDV. At passage 13 the RDV resistance of the lineages ranged from 2.7-to 10.4-fold increase in EC50. Sequence analysis of the three lineage populations identified non-synonymous mutations in the nonstructural protein 12 RNA-dependent RNA polymerase (nsp12-RdRp): V166A, N198S, S759A, V792I and C799F/R. Two of the three lineages encoded the S759A substitution at the RdRp Ser759-Asp-Asp active motif. In one lineage, the V792I substitution emerged first then combined with S759A. Introduction of the S759A and V792I substitutions at homologous nsp12 positions in viable isogenic clones of the betacoronavirus murine hepatitis virus (MHV) demonstrated their transferability across CoVs, up to 38-fold RDV resistance in combination, and a significant replication defect associated with their introduction. Biochemical analysis of SARS-CoV-2 RdRp encoding S759A demonstrated a ~10-fold decreased preference for RDV-triphosphate (RDV-TP) as a substrate, while nsp12-V792I diminished the UTP concentration needed to overcome the template-dependent inhibition associated with RDV. The in vitro selected substitutions here identified were rare or not detected in the >6 million publicly available nsp12-RdRp consensus sequences in the absence of RDV selection. The results define genetic and biochemical pathways to RDV resistance and emphasize the need for additional studies to define the potential for emergence of these or other RDV resistance mutations in various clinical settings.

Existence of blood circulating immune-cell clusters (CICs) comprising antigen-presenting cells and B cells (preprint)

Cell-to-cell physical interactions are involved in almost every physiological processes in multicellular organisms. Although the dynamics of these interactions could be highly diverse and complex in many circumstances, certain cell-to-cell interactions among immune cells have been well studied due importance in understanding disease pathogenesis and immune therapy development 1 . Dendritic cells (DCs) and B cells are directly involved in adaptive immune response against pathogens. Interaction mechanism between these two celltypes is well-known to occur in germinal centers either indirectly via helper T (Th) cells or directly via cell contact. However, there are animal in vitro and in vivo evidence that such direct DC-to-B cell contact can occur outside germinal centers like in peripheral blood or collagen matrix and display antiviral immune-related activity 2,3 . Here, we provide evidence that certain types of antigen presenting cells (APCs) can form robust cell clusters with B cells and circulate in blood. From healthy human blood immune single cell RNA-seq datasets, we detected APC subpopulations (0.34±0.19% of total PBMCs) that were also enriched with well-known naïve B cell markers. We visually observed DC:B doublets and multiplets (∼0.69% of total live PBMCs) in wildtype mouse blood using flow cytometry and microscopic imaging, thus proving the existence of circulating immune-cell clusters (CICs) composed of APCs and B cells. BCR repertoire of these healthy mouse CICs were similar to circulating B cells. Noticeably, frequency of these APC:B CICs were higher COVID-19 patients than healthy donors and their B cell subtype composition (e.g. naïve, plasmablast, IgM + , IgG + ) varied with disease severity.

Remdesivir, Molnupiravir and Nirmatrelvir remain active against SARS-CoV-2 Omicron and other variants of concern. (preprint)

The in vitro effect of GS-441524, remdesivir, EIDD-1931, molnupiravir and nirmatrelvir against the various SARS-CoV-2 VOCs, including Omicron, was determined. VeroE6-GFP cells were pre-treated overnight with serial dilutions of the compounds before infection. The number of fluorescent pixels of GFP signal, determined by high-content imaging on day 4 post-infection, was used as read-out, and the EC50 of each compound on a viral isolate of each VOC was calculated. These experiments were performed in the presence of the Pgp-inhibitor CP-100356 in order to limit compound efflux. A SARS-CoV-2 strain grown from the first Belgian patient sample was used as ancestral strain. All the other isolates were obtained from patients in Belgium as well. Our results indicate that GS-441524, remdesivir, EIDD-1931, molnupiravir and nirmatrelvir retain their activity against the VOCs Alpha, Beta, Gamma, Delta and Omicron. This is in accordance with the observation that the target proteins of these antivirals are highly conserved.

The adenosine analogue prodrug ATV006 is orally bioavailable and has potent preclinical efficacy against SARS-CoV-2 and its variants (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the COVID-19 pandemic, is rapidly evolving. Due to the limited efficacy of vaccination in prevention of SARS-CoV-2 transmission and continuous emergence of variants of concern (VOC), including the currently most prevalent Delta variant, orally bioavailable and broadly efficacious antiviral drugs are urgently needed. Previously we showed that adenosine analogue 69-0 (also known as GS-441524), possesses potent anti-SARS-CoV-2 activity. Herein, we report that esterification of the 5-hydroxyl moieties of 69-0 markedly improved the antiviral potency. The 5-hydroxyl -isobutyryl prodrug, ATV006, showed excellent oral bioavailability in rats and cynomolgus monkeys and potent antiviral efficacy against different VOCs of SARS-CoV-2 in cell culture and three mouse models. Oral administration of ATV006 significantly reduced viral loads, alleviated lung damage and rescued mice from death in the K18-hACE2 mouse model challenged with the Delta variant. Moreover, ATV006 showed broad antiviral efficacy against different mammal-infecting coronaviruses. These indicate that ATV006 represents a promising oral drug candidate against SARS-CoV-2 VOCs and other coronaviruses.

Therapeutic efficacy of an oral nucleoside analog of remdesivir against SARS-CoV-2 pathogenesis in mice. (preprint)

The COVID-19 pandemic remains uncontrolled despite the rapid rollout of safe and effective SARS-CoV-2 vaccines, underscoring the need to develop highly effective antivirals. In the setting of waning immunity from infection and vaccination, breakthrough infections are becoming increasingly common and treatment options remain limited. Additionally, the emergence of SARS-CoV-2 variants of concern with their potential to escape therapeutic monoclonal antibodies emphasizes the need to develop second-generation oral antivirals targeting highly conserved viral proteins that can be rapidly deployed to outpatients. Here, we demonstrate the in vitro antiviral activity and in vivo therapeutic efficacy of GS-621763, an orally bioavailable prodrug of GS-441524, the parental nucleoside of remdesivir, which targets the highly conserved RNA-dependent RNA polymerase. GS-621763 exhibited significant antiviral activity in lung cell lines and two different human primary lung cell culture systems. The dose-proportional pharmacokinetic profile observed after oral administration of GS-621763 translated to dose-dependent antiviral activity in mice infected with SARS-CoV-2. Therapeutic GS-621763 significantly reduced viral load, lung pathology, and improved pulmonary function in COVID-19 mouse model. A direct comparison of GS-621763 with molnupiravir, an oral nucleoside analog antiviral currently in human clinical trial, proved both drugs to be similarly efficacious. These data demonstrate that therapy with oral prodrugs of remdesivir can significantly improve outcomes in SARS-CoV-2 infected mice. Thus, GS-621763 supports the exploration of GS-441524 oral prodrugs for the treatment of COVID-19 in humans.

Long COVID in Hospitalized and Non-Hospitalized Patients in a Large Cohort in Northwest Spain, A Prospective Cohort Study (preprint)

Background: Survivors to COVID-19 have described long-term symptoms after acute disease. These signs constitute a heterogeneous group named long COVID or persistent COVID . Objective: The aim of this study is to describe persisting symptoms six months after COVID-19 diagnosis in a prospective cohort in the Northwest Spain Design: This is a prospective cohort study performed in the COVID-19 Cohort of Galicia Sur Health Institute (COHVID-GS). Participants This cohort includes patients in clinical follow-up in a health area of 569,534 inhabitants after SARS-CoV-2/COVID-19 diagnosis. Clinical and epidemiological characteristics were collected during the follow up. Main measures and key results. A total of 284 patients completed 6 months follow-up, 176 (69.4%) required hospitalization and 29 (10.2%) of them needed critical care. At six months, 119 (48.0%) patients described one or more persisting symptoms. The most prevalent were: extra-thoracic symptoms (39.1%), chest symptoms (27%), dyspnoea (20.6%), and fatigue (16.1%). These symptoms were more common in hospitalized patients (52.3% vs 38.2%) and in women (59.0% vs 40.5%). The multivariate analysis identified Chronic Obstructive Pulmonary Disease (COPD), female gender and tobacco consumption as risk factors for long COVID. Conclusions: . Persisting symptoms are common after COVID-19 especially in hospitalized patients compared to outpatients (52.3% vs. 38.2%). Based on these findings, special attention and clinical follow-up after acute SARS-CoV-2 infection should be provided for hospitalized patients with previous lung diseases, tobacco consumption, and females.

Collaboration between the Fab and Fc Contribute to Maximal Protection Against SARS-CoV-2 Following NVX-CoV2373 Subunit Vaccine with Matrix-M™ Vaccination (preprint)

Recently approved vaccines have shown remarkable protection in limiting SARS-CoV-2 associated disease. However, immunologic mechanism(s) of protection, and how boosting alters immunity to wildtype and newly emerging strains, remains incompletely understood. Here we profiled the humoral immune response in a cohort of non-human primates immunized with a recombinant SARS-CoV-2 spike (S) glycoprotein (NVX-CoV2373) at two dose levels, administered as a one or two-dose regimen with a saponin-based adjuvant Matrix-M™. While antigen dose had minimal effects, boosting significantly altered the humoral response, driving unique vaccine-induced antibody fingerprints. Differences in antibody effector functions and neutralization were associated with protection in the upper and lower respiratory tract, pointing to compartment-specific determinants of protective immunity against infection. Moreover, NVX-CoV2373 elicited antibodies targeting emerging SARS-CoV-2 variants. Collectively, the data presented here suggest that a single dose may prevent disease, but that two doses may be essential to block further transmission of SARS-CoV-2 and emerging variants.Funding: This work was funded by Operation Warp Speed. We thank Colin Mann and Kathryn Hastie for production of Spike antigens. We thank Nancy Zimmerman, Mark and Lisa Schwartz, an anonymous donor (financial support), Terry and Susan Ragon, and the SAMANA Kay MGH Research Scholars award for their support. We acknowledge support from the Ragon Institute of MGH, MIT and Harvard, the Massachusetts Consortium on Pathogen Readiness (Mass CPR), the NIH (3R37AI080289-11S1, R01AI146785, U19AI42790-01, U19AI135995-02, U19AI42790-01, 1U01CA260476 – 01, CIVIC75N93019C00052), National Science Foundation Graduate Research Fellowship Grant No. #1745302, the Gates foundation Global Health Vaccine Accelerator Platform funding (OPP1146996 and INV-001650), and the Musk Foundation.Conflict of Interest: NP, MGX, JHT, BZ, SM, AMG, MJM, ADP, GG, GS, and LE are current or past employees of Novavax, Inc. and have stock options in the company. GA is the founder of Serom Yx Systems, Inc. AZ is a current employee of Moderna, Inc. but conducted this work before employment.Any opinion, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. YG, RC, MJG, CA, KMP, CL, DY, KB, MEM, JL, DM, CM, SS, FA, FK, EOS, DL, and MBF declare no competing interest.Ethical Approval: The work was conducted in accordance with a protocol approved by Texas Biomed’s Institutional Animal Care and Use Committee. All subjects signed informed consent and safety oversight was monitored by a data monitoring board.

The Role of Chest CT in Deciphering Interstitial Lung Involvement: Systemic Sclerosis Versus COVID-19 (preprint)

Background: In clinical practice, the striking similarities observed at computed tomography (CT) between the diseases make it difficult to distinguish a COVID-19 pneumonia from a progression of interstitial lung disease (ILD) secondary to Systemic sclerosis (SSc). The aim of the present study was to identify the main CT features that may help distinguishing SSc-ILD from COVID-19 pneumonia. Methods: This multicentric study included 22 international readers divided in the radiologist group (RAD) and non-radiologist group (nRAD). A total of 99 patients, 52 with COVID-19 and 47 with SSc-ILD, were included in the study.Findings: Fibrosis inside focal ground glass opacities (GGO) in the upper lobes; fibrosis in the lower lobe GGO; reticulations in lower lobes (especially if bilateral and symmetrical or associated with signs of fibrosis) were the CT features most frequently associated with SSc-ILD. The CT features most frequently associated with COVID- 19 pneumonia were: consolidation (CONS) in the lower lobes, CONS with peripheral (both central/peripheral or patchy distributions), anterior and posterior CONS and rounded-shaped GGOs in the lower lobes. After multivariate analysis, the presence of CONS in the lower lobes (p <0.0001) and signs of fibrosis in GGO in the lower lobes (p <0.0001) remained independently associated with COVID-19 pneumonia or SSc-ILD, respectively. A predictive score weas created which resulted positively associated with the COVID-19 diagnosis (96.1% sensitivity and 83.3% specificity).Interpretation: The CT differential diagnosis between COVID-19 pneumonia and SSc-ILD is possible through the combination our score and the radiologic expertise. If an overlap of both diseases is suspected, the presence of consolidation in the lower lobes may suggest a COVID-19 pneumonia while the presence of fibrosis inside GGO may indicate a SSc-ILD.Funding: No Funding were received for this study.Declaration of Interests: SC reports personal fees from NOVARTIS-SANOFI-LILLY-CELTHER-PFIZER-JANSSEN; MK reports grants and personal fees from Boehringer-Ingelheim, personal fees from Corbus, grants and personal fees from Chugai, grants and personal fees from Ono Pharmeceuticals, personal fees from Tanabe-Mitsubishi, personal fees from Astellas, personal fees from Gilead, personal fees from Mochida; ST reports personal fees from Boehringer Ingelheim, personal fees from Roche, outside the submitted work; GS reports personal fees from Boehringer Ingelheim; CB reports personal fees from Actelion, personal fees from Eli Lilly, grants from European Scleroderma Trial and Research (EUSTAR) group, grants from New Horizon Fellowship, grants from Foundation for Research in Rheumatology (FOREUM), grants from Fondazione Italiana per la Ricerca sull'Artrite (FIRA); CV reports grants and personal fees from Boehringer Ingelheim, grants and personal fees from F. Hoffmann-La Roche Ltd.; FL reports lectures fee from Roche and from Boehringer- Ingelheim; CPD reports grants and personal fees from GSK, personal fees from Boerhinger Ingelheim, grants from Servier, grants and personal fees from Inventiva, grants and personal fees from Arxx Therapeutics, personal fees from Corbus, personal fees from Sanofi, personal fees from Roche; FL reports grants and personal fees from GSK, personal fees from Boehringer Ingelheim, personal fees from Orion Pharma, personal fees from AstraZeneca, grants from MSD, personal fees from HIKMA, personal fees from Trudell International, grants and personal fees from Chiesi Farmaceutici, personal fees from Novartis Pharma; MH reports personal fees from Speaking fees from Actelion, Eli lilly and Pfizer; D K reports personal fees from Actelion, grants and personal fees from Bayer, grants and personal fees from Boehringer Ingelhem, personal fees from CSL Behring, grants and personal fees from Horizon, grants from Pfizer, personal fees from Corbus, grants and personal fees from BMS, outside the submitted work; and Dr Khanna is the Chief Medical officer of Eicos Sciences Inc and has stock options. All the mentioned authors declared previous feed outside the submitted work. All other authors declare no competing interests.Ethics Approval Statement: This retrospective, observational, multicentric, international study was approved by the Institutional Ethics Committee of Florence Careggi hospital (protocol number 17104_oss).

Distinct Inflammatory Biomarker Patterns in COVID-19 Associated Multisystem Inflammatory Syndrome in Children (MIS-C) Suggest Overlap between Kawasaki Disease and Macrophage Activation Syndrome (preprint)

Background: Multisystem inflammatory syndrome in children (MIS-C) is a potentially life-threatening hyperinflammatory syndrome that occurs after primary SARS-CoV-2 infection. The pathogenesis of MIS-C remains undefined, and whether specific inflammatory biomarker patterns can distinguish MIS-C from other hyperinflammatory syndromes including Kawasaki disease (KD) and macrophage activation syndrome (MAS) is unknown.Methods: We studied a prospective cohort of nineteen MIS-C and nine KD patients and an established cohort of eleven new onset SJIA and nine MAS associated SJIA patients. Clinical and laboratory features as well as S100A8/A9, S100A12, IL-18, CXCL9 and IL-6 levels were compared between disease groups.Findings: KD and MIS-C patients have similar S100 proteins and IL-18 profiles but are distinguished by significantly higher levels of the IFN-γ-induced chemokine CXCL9 in MIS-C. Stratifying MIS-C patients by CXCL9 levels revealed differential severity of clinical and laboratory presentation. MIS-C with high CXCL9 levels was associated with acute kidney injury, altered mental status, a higher frequency of shock (40 vs 90%), myocardial dysfunction (20 vs 50%), and more severe systemic inflammatory markers, cytopenia, and coagulopathy. The low CXCL9 MIS-C group in contrast resembled KD patients including the frequency of coronary involvement. We also found that elevated S100A8/A9, S100A12 and IL-18 were useful in distinguishing SJIA from KD with high sensitivity and specificity.Interpretation: Our findings show MIS-C is distinguished from KD primarily by elevated CXCL9. The stratification of CXCL9 levels of MIS-C patients provides support for MAS pathophysiology in patients with severe MIS-C, suggesting new approaches for diagnosis and management.Funding: This work was supported by an Academic Research Clinical (ARC) award to AG and GS from the Cincinnati Children’s Research Foundation. GS was supported by NIAMS/NIH K08-AR072075, AG by P30-AR070549, and JRS and GC by T32-AR069512. EV was supported by the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG/448863690).Declaration of Interests: AG has served as a consultant and received research support from Novartis, Sobi, NovImmune and AB2Bio. GS consulting fees from Novartis and SOBI. All other authors report no disclosures.Ethics Approval Statement: The study was approved by the Institutional Review Board (CCHMC IRB2018-2408).

Pharmacokinetics of Orally Administered GS-441524 in Dogs (preprint)

Despite being FDA-approved for COVID-19, the clinical efficacy of remdesivir (Veklury) remains contentious. We previously described the pharmacokinetic, pharmacodynamic and toxicological rationales on the greater suitability of its parent nucleoside, GS-441524, for COVID-19 treatment. Here, we assess the oral bioavailability of GS-441524 in beagle dogs and show that plasma concentrations approximately 24-fold higher than the EC50 against SARS-CoV-2 are easily and safely sustained. These data support translation of GS-441524 as an oral agent for COVID-19.