Molnupiravir and combination of nirmatrelvir and ritonavir (PaxlovidTM) - oral anti-viral drugs in COVID-19: a systematic review

The COVID-19 pandemic situation demands the discovery of newer drugs and/ or repurposing of the existing drugs. The anti-viral drugs approved for COVID-19 are remdesivir and favipiravir. Two more directly acting oral anti-viral drugs have been granted Emergency Use Authorization by US-FDA, molnupiravir on December 23, 2021, and nirmatrelvir and ritonavir (PaxlovidTM) on December 22, 2021. Molnupiravir, an RNA-dependent RNA polymerase (RdRp) inhibitor, has also been approved in the UK and is under review with other regulatory agencies. PaxlovidTM (a combination of the new anti-viral drugs nirmatrelvir and ritonavir) has been developed and approved by US-FDA and CDSCO, India. Nirmatrelvir acts by inhibiting 3CL (chymotrypsin-like) protease enzyme and it is combined with ritonavir to slow down its breakdown by cytochrome P450 enzymes and to increase the bioavailability. Both molnupiravir and PaxlovidTM have been approved for mild and moderate COVID-19 and in patients who have a higher risk of disease progression to severe disease including hospitalisation and death. This article systematically reviews the clinical trials of molnupiravir and PaxlovidTM that evaluated their efficacy and safety against COVID-19 in both published and unpublished literature.

Oral anti-viral therapy for early COVID-19 infection in patients with haematological malignancies: A multicentre prospective cohort.

High rates of lung failure have been reported in haematological patients after SARS-CoV2 infection. An early administration of monoclonal antibodies or anti-virals may improve the prognosis. Oral anti-virals may have a wider use independently of the genetic variations of the virus. Prospective data on anti-virals in haematological malignancies (HMs) are still lacking. Outpatients diagnosed with HM and early COVID-19 infection were prospectively treated with the oral anti-virals nirmatrelvir/ritonavir and molnupiravir. Incidence of lung failure, deaths and adverse events was analysed. Long-term outcome at third month was evaluated. Eighty-two outpatients were evaluable for the study objectives. All patients had been treated for their HM within 12 months. COVID-19-related lung failure was 23.1%. Active HM (aOR = 4.42; p = 0.038) and prolonged viral shedding (aOR = 1.04; p = 0.022) resulted independent predictors of severe infection. The vaccination with three to four doses (aOR = 0.02; p = 0.001) and with two doses (aOR = 0.06; p = 0.006) resulted protective. COVID-19-related deaths at 28 days were 6.1%. All-cause mortality at 90-day follow-up was 13.4% (n. 11) and included opportunistic infections and cardiovascular events. In conclusion, this approach reduced the incidence of lung failure and specific mortality compared to previous cohorts, but patients remain at high risk of further complications.

Efficacy of Sotrovimab (SOT), Molnupiravir (MOL), and Nirmatrelvir/Ritponavir (N/R) and Tolerability of Molnupiravir in Outpatients at High Risk for Severe COVID-19.

OBJECTIVE: The main goal of this study was to assess the potential clinical impact of an outpatient administration of available antivirals including SOT, N/R, and MOL to COVID-19 patients at high risk for disease progression. METHODS: We conducted a retrospective analysis on 2606 outpatient individuals with mild to moderate COVID-19 at risk for disease progression, hospitalization, or death. After receiving either SOT (420/2606), MOL (1788/2606), or N/R (398/2606), patients were followed-up with regarding primary (hospitalization rate) and secondary (treatment and side effects) outcomes by phone. RESULT: A total of 2606 patients were treated at the outpatient clinic (SOT: 420; N/R: 398; MOL: 1788). 3.2% of the SOT patients (1 ICU admission), 0.8% of the MOL patients (2 ICU admissions), and none of the N/R patients were hospitalized. 14.3% of the N/R patients reported strong to severe side effects, exceeding SOT (2.6%) and MOL (5%) patients. A reduction in COVID symptoms after the treatment was experienced by 43% of patients in both the SOT and MOL groups and by 67% of patients in the N/R group, respectively. Women had a higher chance of symptom improvement with MOL (OR 1.2, 95%CI 1.0-1.5). CONCLUSION: All antiviral treatment options effectively prevented hospitalization in high-risk COVID-19 patients and were well tolerated. Side effects were pronounced in patients with N/R.

Estimation of Intangible Costs for Factors Associated with Oral Antiviral Drugs for COVID-19 Treatment: A Conjoint Analysis in Japan.

INTRODUCTION: During the recent coronavirus disease 2019 (COVID-19) pandemic, preferences for factors associated with vaccines have been evaluated. Three oral antiviral drugs have been approved in Japan for patients with mild-to-moderate I COVID-19 symptoms. Although preferences for the drugs may also depend on various factors, these have not been fully evaluated. METHODS: A conjoint analysis was performed based on an online survey in August 2022 to estimate the intangible costs of factors associated with oral antiviral drugs for COVID-19. Respondents were individuals aged 20-69 across Japan. The attributes included the company (Japanese/foreign) that developed the drug, formulation and size of the drug, frequency of administration per day, number of tablets/capsules per dose, number of days until no longer infectious to others, and out-of-pocket expenses. A logistic regression model was applied to estimate the utility of each level for each attribute. The intangible costs were calculated by comparing the utility to the out-of-pocket attribute. RESULTS: Responses were collected from 11,303 participants. The difference between levels was the largest for companies that developed a drug; the intangible costs were JPY 5390 higher for the foreign company than for the Japanese company. The next largest difference was in the number of days until one is no longer infectious. For the same formulation, the intangible cost was lower for small sizes than large sizes. For similar-sized tablets and capsules, the intangible cost was lower for tablets than capsules. These tendencies were similar regardless of COVID-19 infection history and the presence of risk factors for severe COVID-19 in the respondents. CONCLUSION: Intangible costs for factors associated with oral antiviral drugs among the Japanese population were estimated. The results may change as the number of people with a history of COVID-19 infection increases and significant progress is made regarding treatments.

Molnupiravir, Nirmatrelvir/Ritonavir, or Sotrovimab for High-Risk COVID-19 Patients Infected by the Omicron Variant: Hospitalization, Mortality, and Time until Negative Swab Test in Real Life.

Background. Several drugs which are easy to administer in outpatient settings have been authorized and endorsed for high-risk COVID-19 patients with mild-moderate disease to prevent hospital admission and death, complementing COVID-19 vaccines. However, the evidence on the efficacy of COVID-19 antivirals during the Omicron wave is scanty or conflicting. Methods. This retrospective controlled study investigated the efficacy of Molnupiravir or Nirmatrelvir/Ritonavir (Paxlovid®) or Sotrovimab against standard of care (controls) on three different endpoints among 386 high-risk COVID-19 outpatients: hospital admission at 30 days; death at 30 days; and time between COVID-19 diagnosis and first negative swab test result. Multivariable logistic regression was employed to investigate the determinants of hospitalization due to COVID-19-associated pneumonia, whereas time to first negative swab test result was investigated by means of multinomial logistic analysis as well as Cox regression analysis. Results. Only 11 patients (overall rate of 2.8%) developed severe COVID-19-associated pneumonia requiring admission to hospital: 8 controls (7.2%); 2 patients on Nirmatrelvir/Ritonavir (2.0%); and 1 on Sotrovimab (1.8%). No patient on Molnupiravir was institutionalized. Compared to controls, hospitalization was less likely for patients on Nirmatrelvir/Ritonavir (aOR = 0.16; 95% CI: 0.03; 0.89) or Molnupiravir (omitted estimate); drug efficacy was 84% for Nirmatrelvir/Ritonavir against 100% for Molnupiravir. Only two patients died of COVID-19 (rate of 0.5%), both were controls, one (a woman aged 96 years) was unvaccinated and the other (a woman aged 72 years) had adequate vaccination status. At Cox regression analysis, the negativization rate was significantly higher in patients treated with both antivirals-Nirmatrelvir/Ritonavir (aHR = 1.68; 95% CI: 1.25; 2.26) or Molnupiravir (aHR = 1.45; 95% CI: 1.08; 1.94). However, COVID-19 vaccination with three (aHR = 2.03; 95% CI: 1.51; 2.73) or four (aHR = 2.48; 95% CI: 1.32; 4.68) doses had a slightly stronger effect size on viral clearance. In contrast, the negativization rate reduced significantly in patients who were immune-depressed (aHR = 0.70; 95% CI: 0.52; 0.93) or those with a Charlson index ≥5 (aHR = 0.63; 0.41; 0.95) or those who had started the respective treatment course 3+ days after COVID-19 diagnosis (aOR = 0.56; 95% CI: 0.38; 0.82). Likewise, at internal analysis (excluding patients on standard of care), patients on Molnupiravir (aHR = 1.74; 95% CI: 1.21; 2.50) or Nirmatrelvir/Ritonavir (aHR = 1.96; 95% CI: 1.32; 2.93) were more likely to turn negative earlier than those on Sotrovimab (reference category). Nonetheless, three (aHR = 1.91; 95% CI: 1.33; 2.74) or four (aHR = 2.20; 95% CI: 1.06; 4.59) doses of COVID-19 vaccine were again associated with a faster negativization rate. Again, the negativization rate was significantly lower if treatment started 3+ days after COVID-19 diagnosis (aHR = 0.54; 95% CI: 0.32; 0.92). Conclusions. Molnupiravir, Nirmatrelvir/Ritonavir, and Sotrovimab were all effective in preventing hospital admission and/or mortality attributable to COVID-19. However, hospitalizations also decreased with higher number of doses of COVID-19 vaccines. Although they are effective against severe disease and mortality, the prescription of COVID-19 antivirals should be carefully scrutinized by double opinion, not only to contain health care costs but also to reduce the risk of generating resistant SARS-CoV-2 strains. Only 64.7% of patients were in fact immunized with 3+ doses of COVID-19 vaccines in the present study. High-risk patients should prioritize COVID-19 vaccination, which is a more cost-effective approach than antivirals against severe SARS-CoV-2 pneumonia. Likewise, although both antivirals, especially Nirmatrelvir/Ritonavir, were more likely than standard of care and Sotrovimab to reduce viral shedding time (VST) in high-risk SARS-CoV-2 patients, vaccination had an independent and stronger effect on viral clearance. However, the effect of antivirals or COVID-19 vaccination on VST should be considered a secondary benefit. Indeed, recommending Nirmatrelvir/Ritonavir in order to control VST in high-risk COVID-19 patients is rather questionable since other cheap, large spectrum and harmless nasal disinfectants such as hypertonic saline solutions are available on the market with proven efficacy in containing VST.

Molnupiravir Use and 30-Day Hospitalizations or Death in Previously Uninfected Non-hospitalized High-risk Population with COVID-19.

BACKGROUND: Clinical benefit of Molnupiravir (MPV) in COVID-19 infected sub-populations is unclear. METHODS: We used a matched cohort study design to determine the rate of hospitalization or death within 30 days of COVID-19 diagnosis among MPV treated and untreated controls. Participants were non-hospitalized, previously uninfected Veterans with a first confirmed SARS-CoV-2 infection between January 1 and August 31, 2022, who were prescribed MPV within 3 days of COVID-19 diagnosis, and matched individuals who were not prescribed MPV. RESULTS: Among 1,459 matched pairs, the incidence of hospitalization/death was not different among MPV treated vs. untreated controls (48 vs. 44 cases; ARD [95% CI] 0.27 [-0.94,1.49]). No benefit was observed among those >60 or ≤60 years old (ARD 0.27 [-1.25,1.79] vs. -0.29 [-1.22,1.80]), those with specific comorbidities, or by vaccination status. A significant benefit was observed in asymptomatic but not in symptomatic persons (ARD -2.80 [-4.74, -0.87] vs. 1.12 [-0.31,2.55]). Kaplan-Meier curves did not show a difference in proportion of persons who were hospitalized or died among MPV treated compared with untreated controls (logrank P = 0.7). CONCLUSION: MPV was not associated with a reduction in hospitalization or death within 30 days of COVID-19 diagnosis. A subgroup of patients presenting without symptoms experienced a benefit.

Efficacy of Molnupiravir for the Treatment of Mild or Moderate COVID-19 in Adults: A Meta-Analysis.

The aim of this meta-analysis is to evaluate the efficacy of molnupiravir among mild or moderate COVID-19 patients. This meta-analysis was reported according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Two authors independently performed a comprehensive search for relevant studies in PubMed, Cochrane Library, and Web of Science. The keywords used to search for relevant records were "Molnupiravir," "COVID-19," and "efficacy." This meta-analysis included studies that compared the effectiveness of molnupiravir with a placebo for COVID-19 treatment. The primary outcome assessed in this meta-analysis was the composite of hospitalization and all-cause mortality (30 days). In addition, we assessed all-cause mortality and hospitalization separately and the number of patients who tested negative for viral RNA on day five. A total of 10 studies were included in the meta-analysis. Among the 10 studies, five were randomized controlled trials and five were observational studies. Based on the results presented in the meta-analysis, it can be concluded that molnupiravir has a significant impact on reducing all-cause mortality and improving the proportion of patients who test negative for viral RNA on day five. The risk of hospitalization and composite outcome was also lower in molnupiravir-treated patients, although the difference was statistically insignificant. The subgroup analysis showed consistent results across all subgroups, indicating that the effect of molnupiravir is consistent regardless of patient characteristics.

Potential herb‒drug interactions between anti-COVID-19 drugs and traditional Chinese medicine.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide. Effective treatments against COVID-19 remain urgently in need although vaccination significantly reduces the incidence, hospitalization, and mortality. At present, antiviral drugs including Nirmatrelvir/Ritonavir (PaxlovidTM), Remdesivir, and Molnupiravir have been authorized to treat COVID-19 and become more globally available. On the other hand, traditional Chinese medicine (TCM) has been used for the treatment of epidemic diseases for a long history. Currently, various TCM formulae against COVID-19 such as Qingfei Paidu decoction, Xuanfei Baidu granule, Huashi Baidu granule, Jinhua Qinggan granule, Lianhua Qingwen capsule, and Xuebijing injection have been widely used in clinical practice in China, which may cause potential herb-drug interactions (HDIs) in patients under treatment with antiviral drugs and affect the efficacy and safety of medicines. However, information on potential HDIs between the above anti-COVID-19 drugs and TCM formulae is lacking, and thus this work seeks to summarize and highlight potential HDIs between antiviral drugs and TCM formulae against COVID-19, and especially pharmacokinetic HDIs mediated by metabolizing enzymes and/or transporters. These well-characterized HDIs could provide useful information on clinical concomitant medicine use to maximize clinical outcomes and minimize adverse and toxic effects.

Efficacy and Safety of Molnupiravir Treatment for COVID-19: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

INTRODUCTION: There are currently some differences in the research results of molnupiravir. This study aimed to evaluate the efficacy and safety of molnupiravir in the treatment of COVID-19. METHODS: PubMed, Embase, CENTRAL (Cochrane Central Register of Controlled Trials), ClinicalTrials.gov, ICTRP (International Clinical Trials Registry Platform) and medRxiv were searched to identify relevant randomised controlled trials (RCTs) from inception to 1 January 2023. The Cochrane risk of bias tool for randomised trials was used to assess the bias risk of the included studies. Revman 5.4 software was used for meta-analysis. RESULTS: Nine RCTs were included, including 31 573 COVID-19 patients, of whom 15 846 received molnupiravir. The meta-analysis results showed that the molnupiravir group had a higher proportion in terms of clinical improvement (Day 5 RR 2.41, 95% CI 1.18-4.92; Day 10 RR 1.45, 95% CI 1.04-2.01) and real-time polymerase chain reaction negativity (Day 5 RR 2.78, 95% CI 1.38-5.62; Day 10 RR 1.18, 95% CI 1.07-1.31). However, no significant difference was observed between the two groups in terms of mortality, hospitalisation, adverse events and serious adverse events. CONCLUSIONS: Molnupiravir can accelerate the rehabilitation of COVID-19 patients, but it does not significantly reduce mortality and hospitalisation.

Sustainable Stability-Indicating spectra manipulations for the concurrent quantification of a novel Anti-COVID-19 drug and its active Metabolite: Green profile assessment.

Millions of individuals have lost their lives and changed their routines as a direct consequence of exposure to the coronavirus (Covid-19). Molnupiravir (MOL) is an orally bioavailable tiny molecule antiviral prodrug that is effective for curing the coronavirus that produces serious acute respiratory disorder (SARS-CoV-2). Fully green-assessed stability-indicating simple spectrophotometric methods have been developed and fully validated as per ICH criteria. The potential impact of degradation products of drug components on the safety and efficacy of a medication's shelf life is likely to be negligible. The field of pharmaceutical analysis necessitates various stability testing under different conditions. The conduct of such inquiries affords the prospect of predicting the most probable routes of degradation and ascertaining the inherent stability characteristics of the active drugs. Consequently, a surge in demand arose for the creation of an analytical methodology that could consistently measure the degradation products and/or impurities that may be present in pharmaceuticals. Herein, five smart and simple spectrophotometric data manipulation techniques have been produced for the concurrent estimation of MOL and its active metabolite as its possible acid degradation product namely; N-hydroxycytidine (NHC). Structure confirmation of NHC build-up through IR, MS and NMR analyses. All current techniques verified linearity ranging from 10 to 150 µg/ml and 10-60 µg/ml for MOL and NHC, respectively. The limit of quantitation (LOQ) values were in the range of 4.21-9.59 µg/ml, while the limit of detection (LOD) values were ranging from 1.38 - 3.16 µg/ml. The current methods were evaluated in terms of greenness by four assessing methods and confirmed to be green. The significant novelty of these methods depends on their being the first environmentally soundness stability-indicating spectrophotometric approaches for the concurrent estimation of MOL and its active metabolite, NHC. Also, the preparation of purified NHC delivers significant cost savings, instead of purchasing an expensive ingredient. These smart methods were utilized for analyzing the pharmaceutical dosage form which may be of great benefit to the pharmaceutical market.

Biotransformation and brain distribution of the anti-COVID-19 drug molnupiravir and herb-drug pharmacokinetic interactions between the herbal extract Scutellaria formula-NRICM101.

The aim of this study was to explore the effects of herbal drug pharmacokinetic interactions on the biotransformation of molnupiravir and its metabolite ß-D-N4-hydroxycytidine (NHC) in the blood and brain. To investigate the biotransformation mechanism, a carboxylesterase inhibitor, bis(4-nitrophenyl)phosphate (BNPP), was administered. Not only molnupiravir but also the herbal medicine Scutellaria formula-NRICM101 is potentially affected by coadministration with molnupiravir. However, the herb-drug interaction between molnupiravir and the Scutellaria formula-NRICM101 has not yet been investigated. We hypothesized that the complex bioactive herbal ingredients in the extract of the Scutellaria formula-NRICM101, the biotransformation and penetration of the bloodbrain barrier of molnupiravir are altered by inhibition of carboxylesterase. To monitor the analytes, ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLCMS/MS) coupled with the microdialysis method was developed. Based on the dose transfer from humans to rats, a dose of molnupiravir (100 mg/kg, i.v.), molnupiravir (100 mg/kg, i.v.) + BNPP (50 mg/kg, i.v.), and molnupiravir (100 mg/kg, i.v.) + the Scutellaria formula-NRICM101 extract (1.27 g/kg, per day, for 5 consecutive days) were administered. The results showed that molnupiravir was rapidly metabolized to NHC and penetrated into the brain striatum. However, when concomitant with BNPP, NHC was suppressed, and molnupiravir was enhanced. The blood-to-brain penetration ratios were 2% and 6%, respectively. In summary, the extract of the Scutellaria formula-NRICM101 provides a pharmacological effect similar to that of the carboxylesterase inhibitor to suppress NHC in the blood, and the brain penetration ratio was increased, but the concentration is also higher than the effective concentration in the blood and brain.

Liver injury caused by SARS-CoV-2 delta and omicron-variant in Taiwan

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has recently emerged and spread globally. An outbreak of coronavirus disease 2019 (COVID-19) caused by the Delta variant occurred in Southern Taiwan in June 2021 and has been eliminated [1]. However, in April 2022, there was an outbreak of the Omicron variant in Taiwan. Fifteen patients with Omicron variant were admitted to our hospital from April 26 to May 1, 2022. We compared the clinical characteristics of the patients with the Delta variant in June 2021 and the Omicron variant in April 2022 (Table 1). These laboratory data were the first laboratory data at admission, and no anti-COVID-19 therapy was prescribed before these data. There were no differences in age (59.9 vs. 57.1 years, P = 0.96), male gender (63.6 vs. 60.0%, P = 1.00), diabetes ratio (27.3 vs. 35.7%, P = 1.00), body mass index (25.0 vs. 26.0 kg/m2, P = 1.00), pneumonia ratio (18.2 vs. 40.0%, P = 0.40) between the Delta and Omicron variants. There were also no differences in serum levels of aspartate aminotransferase (AST) (40.1 vs. 25.8 IU/L, P = 0.24) and alanine aminotransferase (ALT) (26.3 vs. 27.2 IU/L, P = 0.64) between the two groups. All the patients with the Omicron variant were symptomatic. The most common symptoms were upper respiratory tract infections (60.0%) (Supplementary Table 1). Six patients developed pneumonia without mechanical ventilator support requirement during admission (40.0%). Remdesivir, Paxlovid, or Molnupiravir were prescribed to patients according to their clinical conditions. Among the patients with the Omicron variant, nine (60.0%) had past medical history of diabetes, four (26.7%) had hypertension, three had chronic kidney disease (20.0%), and three had malignancy history (20.0%). COVID-19 might cause liver injury and lead to a more unfavorable prognosis [2]. In this study, about one-fifth of the patients suffered from liver injury, which was similar to previous studies [3]. There was no difference in liver injury between the Delta and Omicron variants in our study, which echoes previous research [4]. COVID-19 vaccination might protect against symptomatic diseases caused by the Omicron variant [5]. Vaccination rates have increased since 2021. In the study, over ninety percent of the patients have received at least two doses of vaccination. In conclusion, we demonstrated no difference in liver injury ratio between the Delta and Omicron variants. To our knowledge, this is the first report that compares the Delta and Omicron variants in Taiwan.

Real world experience of drug-drug interactions for HCV patients receiving pan-genotypic direct-acting antivirals in the era of COVID-19 pandemic

Background and Aims: The treatment of chronic hepatitis C (CHC) has evolved from genotype-specific to pan-genotypic direct acting antivirals (DAAs) with high efficacy and safety. However, drug-drug interactions (DDIs) must be avoided when used in combination with other medications, especially with the possible concomitant use of COVID-19 infection antivirals during the COVID-19 pandemic. This study aimed to access the potential DDIs of concomitant drugs with pan-genotypic DAAs and COVID-19 infection antivirals, and actual incidence of DDIs in real-world experience. Method(s): From January 2022 to October 2022, consecutive 116 HCV patients receiving pan-genotypic DAAs were retrospectively enrolled in Taipei Veterans General Hospital. The number of comedications and their potential DDIs with three pan-genotypic DAA regimens and three COVID-19 infection antivirals were analyzed. The actual incidence of DDIs during DAAs treatment were also investigated. Result(s): The mean age was 60.9 years old, with male predominant (55.2%). Of them, 12 (10.3%) patients had cirrhosis, and 24 (20.7%) patients had diabetes mellitus. Most patients were within Child-Pugh class A (109/116, 94.0%). The distribution of HCV genotypes was 8.6% in GT 1a, 36.2% in GT 1b, 39.7% in GT 2, 6.9% in GT 6, and 8.6% in indeterminate genotype, respectively. Of them, 43 (37.1%) patients received GLE/PIB, 69 (59.5%) received SOF/VEL 7plusmn;RBV, and 4 (3.4%) received SOF/VEL/VOX as DAAs regimen. Noteworthy, four patients had COVID-19 infection during DAAs treatment course. The rates of ETVR and SVR12 were 97.6% and 95.3%. The mean number of concomitant medications was 2.01. The distribution of concomitant drugs was 64.7% with no concomitant drug, 11.2% with 1-3 drugs, 11.2% with 4-6 drugs, 9.5% with 7-9 drugs, and 3.4% had more than 9 drugs, respectively. In potential contraindicated (red) DDI class, GLE/PIB was the most prevalent (7.3%), followed by SOF/VEL/VOX (6.4%), and SOF/VEL (1.8%) for non-cirrhosis and compensated cirrhosis patients;and no red DDI occurred in decompensated cirrhosis patients. In addition, the percentage of patients without potential DDIs was higher with SOF/VEL (79.8%) than with the other regimens. The potential red DDIs were predominantly with lipid-lowering agents for DAAs. For potential red DDI class with COVID-19 infection antivirals, Nirmatrelvir/Ritonavir was the most prevalent (6%), followed by Remdesivir (0.9%), and no potential DDIs with Molnupiravir. For COVID-19 antivirals, the potential red DDIs was mainly with central nervous system drugs. Finally, the actual incidence of DDIs during DAAs treatment showed no red DDI occurred for all patients, and GLE/PIB was the most prevalent (93%) of no potential DDIs. Conclusion(s): The potential DDIs between these comedications differed, with the most potential DDIs occurring with GLE/PIB and Nirmatrelvir/Ritonavir. After careful assessment of comedications and their potential DDIs, the actual incidence of DDIs could be reduced, and optimize safety in real-world practice.

Safety Profile of Molnupiravir with Significant Effect on COVID-19: A Review

Background: As the COVID era unfolds, researchers reveal that rapid changes in viral genetic material allow viruses to circumvent challenges triggered by the host immune system and resist anti-viral drugs, potentially leading to persistent viral manifestations in host cells. Molnupiravir (RNA-dependent RNA polymerase inhibitor) is a novel anti-viral medicine promising a vital role in coming setbacks.Objectives: This review aims to clarify the safety and efficacy of the molnupiravir molecule in light of existing case studies. As a result, it is intended to explore and discuss the molecular structure, mechanism of action, discovery and development process, preclinical research, clinical investigations, and other subtopics.Methods: A total of 75 publications were searched using multiple engines, such as Google Scholar, PubMed, Web of Science, Embase, Cochrane Library, ClinicalTrials.gov, and others, with a constraint applied to exclude publications published over 11 years ago. Molnupiravir, safety, efficacy, COVID- 19, RdRp, PK-PD, and clinical study were utilized as keywords.Results: Clinical results on molnupiravir are supported by investigations that were recently disclosed in a study on both sex volunteers (male and female) with an age restriction of 19 to 60 years, followed by a Phase-3 Clinical Trial (NCT04575584) with 775 randomly assigned participants and no fatalities reported due to treatment.Conclusion: Molnupiravir proved a high level of safety, allowing it to be tested further. This review supports the safety and efficacy of this molecule based on the established evidence, which claims the most anticipated employment of molnupiravir in COVID protocol.

Discovery of Novel Cysteine Protease Inhibitors for the Treatment of Coronavirus (COVID-19).

The application describes compounds, such as compounds of general Formula, with warheads and their use in treating medical diseases or disorders, such as viral infections. Pharmaceutical compositions and synthetic methods of various compounds with warheads are included. The compounds are inhibitors of proteases, such as the 3C, CL- or 3CL-like protease.

MECHANISM AND RESISTANCE STUDIES OF SARS-CoV-2 MPRO INHIBITOR POMOTRELVIR (PBI-0451)

Background: The unprecedented scale of the COVID-19 pandemic and rapid evolution of SARS-CoV-2 variants underscores the need for broadly active inhibitors with a high barrier to resistance. The coronavirus main protease (Mpro) is an essential viral enzyme required for viral polyprotein processing and is highly conserved across human coronaviruses. Pomotrelvir (PBI-0451) is a novel Mpro inhibitor currently completing phase 2 clinical trial. Here we describe the mechanism of action, broad activity against SARS-CoV-2 clinical isolates, combination studies with other SARS-CoV-2 inhibitors and favorable resistance profile of pomotrelvir. Method(s): The kinetic parameters of pomotrelvir Mpro inhibition and its interaction with nirmaltrevir were determined in a kinetic protease assay. The IC50s of pomotrelvir on mutant Mpro proteins were measured in an endpoint Mpro assay. Combination studies of pomotrelvir with remdesivir and molnupiravir were carried out in A549-hACE2 cells infected with SARS-CoV-2 NLuc virus. Activity against SARS-CoV-2 clinical variants was assessed by infection of A549-ACE2-TMPRSS2 cells followed by immunostaining of the viral nucleocapsid protein. Result(s): Pomotrelvir is a potent competitive inhibitor of SARS-CoV-2 Mpro (Ki =2.7 nM). Binding of pomotrelvir and the Mpro inhibitor nirmatrelvir to the active site is mutually exclusive. In the SARS-CoV-2 NLuc assay, pomotrelvir is additive when combined with remdesivir or molnupiravir, two nucleoside analogs targeting viral RNA synthesis. When the effect of Mpro substitutions previously selected in a resistance study of pomotrelvir were analyzed in an enzyme assay, only Mpro-N133H showed a significant increase in IC50 (45-fold). The catalytic efficiency of Mpro-N133H is reduced by 10-fold and the recombinant virus SARSCoV-2 (WA1) -N133H is not viable, suggesting that N133H has lower replicative fitness. Lastly, pomotrelvir exhibits broad activity against all SARS-CoV-2 clinical isolates tested to date, including five omicron variants. Conclusion(s): PBI-0451 is a potent competitive inhibitor of SARS-CoV-2 Mpro and is broadly active against SARS-CoV-2 clinical isolates including omicron variants. Results from inhibitor interaction studies support the potential combination of pomotrelvir with remdesivir and molnupiravir but not nirmatrelvir. Enzymatic characterization of in vitro selected pomotrelvir resistant variants indicates they either confer no resistance or have reduced fitness.

Hospitalisation and death in lung transplant recipients following COVID-19 infection

Introduction/Aim: Rates of hospitalisation and death from COVID-19 in lung transplant (LTx) recipients vary internationally. We aimed to assess risk factors for this in an Australian cohort. Method(s): We performed a retrospective cohort study of all LTx recipients between January 2020 and September 2022. LTx recipients with COVID-19 were included. Baseline characteristics and treatments were recorded. Multivariate logistic regression was performed to identify risk factors associated with hospitalisation and death. Result(s): 128/387 (33%) recipients tested positive to SARS-CoV-2 during the study period, 97.6% during the Omicron waves with 40(31.3%) requiring hospitalisation and 10 (7.8%) died. The median (IQR) recipient age was 50.6 (22-77). The cohort was of Caucasian ethnicity 105 (82%), 48% were female with high vaccination rates (98.4%). Chronic lung allograft dysfunction (CLAD) was present in 48 (37.5%). 103 (80.5%) of patients received early SARS-CoV-2 treatment with either Sotrovimab 84(65%), Molnupirivir 50(39%) or combination 31(24%). 25 patients (19.5%) received no early treatment. All hospitalised patients received Remdesivir and Dexamethasone as per local treatment protocols. Regarding risk of hospitalisation, multivariate analysis showed that recipient age (1-unit change OR 1.04 95% CI 1.01-1.07 p = 0.019) was associated with an increased risk, whereas Molnupiravir was protective (OR 0.32 95% CI 0.13-0.80 p = 0.02). In univariable analysis, increasing age (1-unit change, OR 1.07 95% CI 1.02-1.129 p = 0.01) and severe disease (OR 9.95 95% CI 2.58-38.32 p =< 0.001) were associated with an increased risk of death. Male gender, non-Caucasian ethnicity, CLAD, CKD stage 3-5 were correlated with death with weak association. Conclusion(s): Recipient age is a significant risk factor for both hospitalisation and death, and older patients with COVID-19 should be monitored closely during COVID-19 illness. Molnupirivir is protective against hospitalisation, with Sotrovimab having a weak association. Further analysis of the protective effect of pre-exposure prophylaxis with emerging therapies such as Evusheld would be helpful to fully evaluate the currently available early disease therapies in Australia.

Nirmatrelvir and Molnupiravir Coadministration Modifies Preclinical Viral Exposure

Background: Implementation of vaccination programmes has had a transformational impact on control of the SARS-CoV-2 pandemic, but the need for effective antiviral drugs remains. Molnupiravir (MPV) targets viral RNA polymerase inhibiting replication via lethal mutagenesis and nirmatrelvir (NTV) is a protease inhibitor boosted with ritonavir when given clinically. This study aimed to assess the virological efficacy of NTV and MPV individually and in combination against the SARS-CoV-2 BA.1 Omicron variant in a K18-hACE2 mouse model. Method(s): K18-hACE2 mice were inoculated intranasally with 103 PFU of SARSCoV-2 BA.1 Omicron (B.1.1.529). After 24 hours, mice were orally dosed q12H, as outlined in Figure 1. At 2, 3, and 4-days post infection mice were sacrificed, and lung samples harvested. Animals were weighed and monitored daily throughout. Subsequently, viral replication in the lung was quantified using qRT-PCR to measure total (N-gene) and sub-genomic (E-gene) viral RNA. Data were normalized to 18S for quantitation. Viral exposures expressed as Areas Under viral load Curves (AUCs) were calculated by the trapezoidal method using mean values at each timepoint. Separate studies in Syrian golden hamsters using individual drugs were also conducted, and total serum IgG was measured by ELISA at 4-days post infection. Result(s): Mice gained weight in all groups post-treatment, with no significant difference between groups. A reduction in lung viral exposure was evident in all treatment groups compared to the vehicle control dosed mice (Figure 1). Coadministration of NTV with MPV displayed a trend towards lower lung viral exposure compared to the vehicle control with ~40-and ~45-fold reduction in AUC for N-and SgE-gene assays, respectively. Dosed individually, NTV and MPV reduced viral exposure 5.7-and 7.7-fold for the N-gene assay, respectively. Differences in total serum IgG concentrations were evident between vehicle and NTV-(34-fold reduction, P=0.018), and MPV-(4.2-fold reduction, P=0.053) treated hamsters. Conclusion(s): These data show virological efficacy of NTV and MPV against the SARS-CoV-2 BA.1 Omicron variant. The combination of NTV and MPV demonstrated a lower viral RNA exposure in the lung than either drug alone, albeit not statistically significant. Initial data indicate potential immune alterations in NTV and MPV dosed hamsters. Studies to clarify the utility of NTV/ MPV combinations and further characterize the impact of antiviral therapy on IgG are warranted.

SARS-CoV-2 ANTIVIRAL ACTIVITY OF ZOTATIFIN, A HOST-TARGETING eIF4A INHIBITOR

Background: Zotatifin (eFT226) is a potent and selective inhibitor of eukaryotic initiation factor 4A (eIF4A), a host RNA helicase required for SARS-CoV-2 replication. Zotatifin selectively inhibits translation of ribonucleic acids (RNAs) containing specific short polypurine motifs in their 5-prime (5') regions. Two such highly conserved motifs are found in the SARS-CoV-2 genome. Zotatifin is currently being evaluated in a Phase 1b dose escalation study in 36 patients with mild to moderate COVID disease. In this in vitro study, we evaluated the selectivity of zotatifin's inhibition of SARS-CoV-2 translation, the antiviral activity of zotatifin alone against different human coronaviruses and the antiviral activity of zotatifin in combination with other antivirals against SARSCoV-2. Method(s): The selectivity of zotatifin for viral translation was evaluated in a cell-based reporter assay wherein luciferase translation was driven by 5'-sequences from SARS-CoV-2 or tubulin, a housekeeping gene. The antiviral activity of zotatifin was evaluated against SARS-CoV-1, SARS-CoV-2 variants (Wash/1/2020 (ancestral), delta, omicron BA.2), MERS-CoV and HCoV-299E in primary or established cell lines using cytopathic effect or infectious virus as endpoints. The antiviral activity of zotatifin in combination with remdesivir, N-hydroxycytidine (NHC;active nucleoside analogue metabolite of molnupiravir), nirmatrelvir, baricitinib or sotrovimab was evaluated against SARS-CoV-2 and analyzed by the method of Pritchard and Shipman. Result(s): Zotatifin inhibited the translation of the SARS-CoV-2 luciferase reporter construct with a mean IC50 of 3 nM and was ~14-fold less potent in inhibiting the tubulin reporter construct. Zotatifin potently inhibited the replication of all human coronaviruses tested with 50% effective concentrations (EC50s) ranging from 0.016 to 37.3 nM. The 50% cytotoxic concentration (CC50) value for zotatifin was 250 to >100,000 nM, yielding selectivity indices of 7 to >6250. Zotatifin was ~20 to >100-fold more potent than remdesivir, nirmatrelvir or NHC (figure) and demonstrated additive interactions when combined with remdesivir, NHC, nirmatrelvir, baricitinib or sotrovimab in vitro. Conclusion(s): The potent broad-spectrum activity of zotatifin against a variety of human coronaviruses and additive activity when combined with different anti-SARS-CoV-2 antivirals highlight the advantages of eIF4A as a target and warrant further evaluation in human clinical trials.