ETIDIOH - NEW

  Abstract While treatment with nirmatrelvir/ritonavir or molnupiravir is effective in lowering the rate of severe COVID-19 , the effectiveness of these antivirals in reducing the risk of cardiovascular outcomes, especially among the hospitalized population, remains largely unknown . In this study, we assessed the real-world effectiveness of nirmatrelvir/ritonavir and molnupiravir on short- and long-term cardiovascular complications of COVID-19 using a target trial emulation design. Two target trials of COVID-19 antivirals were emulated by using a territory-wide, population-based, retrospective cohort of hospitalized patients in Hong Kong . Nine cardiovascular outcomes were evaluated in both short-term (day 0–21) and long-term (day 22–365) post-SARS-CoV-2 infection. Compared with the control group , the use of nirmatrelvir/ritonavir was associated with a significantly lower one-year risk of cardiovascular mortality , composite cardiovascular complications, major adverse cardiac eve...

  Summary Background Ensitrelvir is an oral antiviral treatment for COVID-19 with the same molecular target (the main protease ) as ritonavir-boosted nirmatrelvir —the current oral first-line treatment. We aimed to compare the clinical antiviral effects of the two drugs. Methods In an open-label, phase 2, randomised, controlled, adaptive pharmacometric platform trial, low-risk adult outpatients aged 18–60 years with early symptomatic COVID-19 (<4 days of symptoms) were recruited from hospital acute respiratory infection clinics in Thailand and Laos . Patients were randomly assigned in blocks (block sizes depended on the number of interventions available) to one of eight treatment groups, including oral ensitrelvir and oral ritonavir-boosted nirmatrelvir at standard doses, both given for 5 days, and no study drug. The primary endpoint was the oropharyngeal SARS-CoV-2 viral clearance rate assessed between day 0 and day 5 in the modified intention-to-treat population (defined as pa...

  Abstract Objectives There have been few studies in pregnant women of medications that are used to reduce severe complications from COVID-19 infection. Currently, nirmatrelvir/ritonavir (Paxlovid) is recommended by the National Institutes for Health to treat non-hospitalized pregnant patients with mild-to-moderate COVID-19 illness. The aim of this study was to determine the transplacental passage of molnupiravir, nirmatrelvir/ritonavir and favipiravir utilizing an ex vivo placental perfusion model. Methods Human placental cotyledons were continuously perfused in a double open circuit. The study molecules and antipyrine, a marker of placental viability, were dissolved in the maternal solution. The experiment was conducted over 90 minutes, and every 5 minutes, samples of the maternal solution and fetal exchange solutions were collected for analysis. We calculated the concentrations of study molecules, fetal transfer ratios and the clearance indexes to determine placental transfer. R...

Abstract Recent investigations have demonstrated a relationship between the persistence of SARS-CoV-2 and post-COVID-19 conditions . Building upon a potential connection between SARS-CoV-2 persistence and early virologic rebound, we examine the association of early virologic rebound with post-acute mortality and hospitalization due to post-acute sequelae among hospitalized patients with COVID-19 in Hong Kong . Our study includes 13,859, 3959, and 4502 patients in the all-patient, nirmatrelvir/ritonavir, and molnupiravir group , respectively. Results show that patients who experienced virologic rebound exhibited a significantly higher risk of post-acute mortality (hazard ratio [HR], 1.52; 95% confidence interval [CI], 1.36–1.70) with a risk difference [RD] of 7.19%, compared with patients without virologic rebound. A similar increase in the risk of post-acute mortality is also observed in nirmatrelvir/ritonavir-treated patients (HR, 1.78; 95% CI, 1.41–2.25; RD, 12.55%) and molnupiravir-...

Summary Background Nirmatrelvir–ritonavir is approved for adults with mild-to-moderate COVID-19 who are at risk of severe disease . There are little clinical data to guide the duration of therapy in patients who are immunocompromised. We aimed to compare the approved 5-day regimen of nirmatrelvir–ritonavir with 10-day and 15-day regimens. Methods This placebo-controlled, randomised, double-blind, phase 2 trial enrolled non-hospitalised, immunocompromised individuals aged 12 years or older with symptomatic COVID-19 from 73 sites across nine countries. Participants were randomly assigned (1:1:1) to receive 300 mg nirmatrelvir and 100 mg ritonavir orally twice per day for 5, 10, or 15 days. Randomisation was stratified according to whether participants were considered immunocompromised due to use of corticosteroids or tumour necrosis factor blockers. Investigators, participants, and caregivers were masked to the assigned study group. The primary endpoint was proportion of randomly assigne...

Summary Background Molnupiravir and nirmatrelvir–ritonavir are oral antivirals that have shown efficacy in preventing disease progression in outpatients with COVID-19. We aimed to evaluate these treatments for patients hospitalised with COVID-19 pneumonia, for whom data on these antivirals are scarce. Methods The RECOVERY trial is a randomised, controlled, open-label, adaptive platform trial testing treatments for COVID-19 . In this study we report the molnupiravir and nirmatrelvir–ritonavir comparisons from the RECOVERY trial. In each comparison, participants aged 18 years and older were randomly allocated (1:1) to the relevant antiviral (5 days of molnupiravir 800 mg twice daily or 300 mg nirmatrelvir and 100 mg ritonavir twice daily) in addition to usual care, or to usual care alone. The molnupiravir comparison was conducted at 75 hospitals in the UK, two in Nepal, and two in Indonesia ; the nirmatrelvir–ritonavir comparison was conducted at 32 hospitals in the UK. Participants coul...

Summary Background The substantial burden of post-COVID-19 condition (also known as long COVID) underscores the need for effective pharmacological interventions. Given that viral persistence has been hypothesised as a potential cause of long COVID, antiviral therapy might offer a promising approach to alleviating long COVID symptoms. We therefore investigated the efficacy, safety, and tolerability of nirmatrelvir–ritonavir for treating long COVID. Methods In this phase 2, decentralised, double-blind, randomised controlled trial , adults (aged ≥18 years) from the 48 states across the contiguous USA, with previous documented SARS-CoV-2 infection and long COVID symptoms starting within 4 weeks of initial infection and persisting for at least 12 weeks, were eligible for inclusion. Key exclusion criteria were use of nirmatrelvir–ritonavir within the previous 2 months, CYP3A4-dependent medications, or strong CYP3A4 inducers; acute medical illness such as SARS-CoV-2 infection within the past ...

ABSTRACT In a subset of SARS-CoV-2-infected individuals treated with the antiviral nirmatrelvir -ritonavir, the virus rebounds following treatment. The mechanisms driving this rebound are not well understood. We used a mathematical model to describe the longitudinal viral load dynamics of 51 individuals treated with nirmatrelvir-ritonavir, 20 of whom rebounded. Target cell preservation , either by a robust innate immune response or initiation of N-R near the time of symptom onset, coupled with incomplete viral clearance , appears to be the main factor leading to viral rebound. Moreover, the occurrence of viral rebound is likely influenced by the time of treatment initiation relative to the progression of the infection, with earlier treatments leading to a higher chance of rebound . A comparison with an untreated cohort suggests that early treatments with nirmatrelvir-ritonavir may be associated with a delay in the onset of an adaptive immune response . Nevertheless, our model demonstra...

Abstract SARS-CoV-2 main protease, Mpro , is responsible for processing the viral polyproteins into individual proteins, including the protease itself. Mpro is a key target of anti-COVID-19 therapeutics such as nirmatrelvir (the active component of Paxlovid). Resistance mutants identified clinically and in viral passage assays contain a combination of active site mutations (e.g., E166V, E166A, L167F), which reduce inhibitor binding and enzymatic activity, and non-active site mutations (e.g., P252L, T21I, L50F), which restore the fitness of viral replication. To probe the role of the non-active site mutations in fitness rescue, here we use an Mpro triple mutant (L50F/E166A/L167F) that confers nirmatrelvir drug resistance with a viral fitness level similar to the wild-type. By comparing peptide and full-length Mpro protein as substrates, we demonstrate that the binding of Mpro substrate involves more than residues in the active site. Particularly, L50F and other non-active site mutations...