Effectiveness of COVID-19 treatment with nirmatrelvir-ritonavir or molnupiravir among U.S. Veterans: target trial emulation studies with one-month and six-month outcomes

COVID-19 therapeutics

SUMMARYSince the emergence of COVID-19 in 2020, an unprecedented range of therapeutic options has been studied and deployed. Healthcare providers have multiple treatment approaches to choose from, but efficacy of those approaches often remains controversial or compromised by viral evolution. Uncertainties still persist regarding the best therapies for high-risk patients, and the drug pipeline is suffering fatigue and shortage of funding. In this article, we review the antiviral activity, mechanism of action, pharmacokinetics, and safety of COVID-19 antiviral therapies. Additionally, we summarize the evidence from randomized controlled trials on efficacy and safety of the various COVID-19 antivirals and discuss unmet needs which should be addressed.

Molnupiravir Use Among Patients with COVID-19 in Real-World Settings: A Systematic Literature Review

INTRODUCTION

Molnupiravir (MOV) is an oral antiviral for the treatment of individuals with mild-to-moderate COVID-19 and at high risk of progression to severe disease. Our objective was to conduct a systematic literature review (SLR) of evidence on the effectiveness of MOV in reducing the risk of severe COVID-19 outcomes in real-world outpatient settings.

METHODS

The SLR was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines and using pre-determined population, intervention, comparison, outcome, time, and study design inclusion criteria. Eligible studies were published between January 1, 2021, and March 10, 2023, and evaluated the real-world effectiveness of MOV compared to no treatment in reducing the risk of severe COVID-19 outcomes among outpatients ≥ 18 years of age with a laboratory-confirmed diagnosis of SARS-CoV-2 infection.

RESULTS

Nine studies from five countries were included in the review. The size of the MOV-treated group ranged from 359 to 7818 individuals. Omicron variants of SARS-CoV-2 were dominant in all study periods. Most studies noted differences in the baseline characteristics of the MOV-treated and untreated control groups, with the treated groups generally being older and with more comorbidities. Eight studies reported that treatment with MOV was associated with a significantly reduced risk of at least one severe COVID-19 outcome in at least one age group, with greater benefits consistently observed among older age groups.

CONCLUSIONS

In this SLR study, treatment with MOV was effective in reducing the risk of severe outcomes from COVID-19 caused by Omicron variants, especially for older individuals. Differences in the ages and baseline comorbidities of the MOV-treated and control groups may have led to underestimation of the effectiveness of MOV in many observational studies. Real-world studies published to date thus provide additional evidence supporting the continued benefits of MOV in non-hospitalized adults with COVID-19.

Economic burden of COVID-19 for employers and employees in the United States

OBJECTIVE

Describe the economic burden of COVID-19 on employers and employees in the United States (US).

METHODS

A targeted literature review was conducted to evaluate the impact of COVID-19 on US-based employers and employees in terms of healthcare resource utilization (HCRU), medical costs, and costs associated with work-loss. Searches were conducted in MEDLINE, Embase, and EconLit using a combination of disease terms, populations, and outcomes to identify articles published from January 2021 to November 4, 2022. As data from the employer perspective were lacking, additional literature related to influenza were included to contextualize the impact of COVID-19, as it shifts into an endemic state, within the existing respiratory illness landscape.

RESULTS

A total of 41 articles were included in the literature review. Employer and employee perspectives were not well represented in the literature, and very few articles overlapped on any given outcome. HCRU, costs, and work impairment vary by community transmission levels, industry type, population demographics, telework ability, mitigation implementation measures, and company policies. Work-loss among COVID-19 cases were higher among the unvaccinated and in the week following diagnosis and for some, these continued for 6 months. HCRU is increased in those with COVID-19 and COVID-19-related HCRU can also continue for 6 months.

CONCLUSIONS

COVID-19 continues to be a considerable burden to employers. The majority of COVID-19 cases impact working age adults. HCRU is mainly driven by outpatient visits, while direct costs are driven by hospitalization. Productivity loss is higher for unvaccinated individuals. An increased focus to support mitigation measures may minimize hospitalizations and work-loss. A data-driven approach to implementation of workplace policies, targeted communications, and access to timely and appropriate therapies for prevention and treatment may reduce health-related work-loss and associated cost burden.

Hospitalization Among Patients Treated With Molnupiravir: A Retrospective Study of Administrative Data

PURPOSE

Molnupiravir is an oral antiviral agent authorized for emergency use to treat mild to moderate cases of coronavirus disease 2019 (COVID-19) in adults at high risk for progression to severe clinical outcomes. This study aimed to describe patient characteristics and health outcomes in a cohort of adult patients treated with molnupiravir in an outpatient setting in the United States.

METHODS

This was a retrospective cohort study of adults identified in the HealthVerity database with a pharmacy claim for molnupiravir between December 24, 2021, and April 14, 2022. Hospitalization and health care use were assessed over the 28 days after the molnupiravir pharmacy claim.

FINDINGS

Among 26,554 patients identified, 71.1% were aged ≥50 years and 58.9% were female. A total of 8794 patients (33.1%) had received at least 1 dose of the COVID-19 vaccine. The most prevalent risk factors for severe COVID-19 identified were hypertension (45.1%), steroid and/or immunosuppressant use (39.6%), and being obese or overweight (24.6%), with 79.1% of patients having ≥1 risk factor. The majority (61.0%) of patients were prescribed comedications contraindicated with or had the potential for major drug-drug interactions with ritonavir-containing regimens. Within 28 days after initiating molnupiravir, 3.3% of patients were hospitalized for any cause and 1.7% for COVID-19-related reasons. Among all hospitalized patients, 9.2% were admitted to an intensive care unit, 3.9% received oxygen, and 3.8% required mechanical ventilation.

IMPLICATIONS

The majority of patients treated with molnupiravir in early 2022 had at least one risk factor for severe COVID-19 and had comedications that could require treatment modification or monitoring if given a ritonavir-containing regimen. Hospitalization was uncommon after treatment with molnupiravir, with COVID-19-related inpatient admission in <2% of patients. Among those hospitalized, patient use of intensive care and oxygen-based resources was infrequent. The study design, however, does not permit any conclusions regarding the effectiveness of molnupiravir.

Efficacy and safety of paxlovid (nirmatrelvir/ritonavir) in the treatment of COVID-19: An updated meta-analysis and trial sequential analysis

Our study is aimed to access the efficacy and safety outcomes for coronavirus disease 2019 (COVID-19) patients treated with Paxlovid. According to inclusion and exclusion criteria, databases were used to retrieve articles from 1 January 2020 to 1 January 2023. Article screening, quality evaluation and data extraction were completed and cross-checked. The meta-analysis and trial sequential analysis (TSA) were conducted using RevMan, StataMP, and TSA software. A total of 42 original articles were included. Overall meta-analysis results showed that for death, hospitalisation, death or hospitalisation, emergency department (ED) visit, intensive care unit (ICU) admission, and extra oxygen requirement outcomes, every odds ratio (OR) was <1 and p < 0.05. For rebound outcome, the OR was >1 and p > 0.05. For adverse events (AEs) outcome, the OR was >1 and p < 0.05. In conclusion, Paxlovid effectively reduced the risks of death, hospitalisation, death or hospitalisation, ED visit, ICU admission, and extra oxygen requirement. There was no significant statistical difference considering rebound, but people should pay attention to possible AEs. However, for rebound and AEs outcomes, observations in certain subgroups suggested conclusions contrary to the overall meta-analysis. Trial sequential analysis indicated these two outcomes have a risk of false negative or false positive conclusions, so additional original studies are needed for further validation.

Nirmatrelvir plus ritonavir remains effective in vaccinated patients at risk of progression with COVID-19: A systematic review and meta-analysis

Background

The efficacy of nirmatrelvir plus ritonavir (NMV-r) for vaccinated COVID-19 patients at high risk of progression is not adequately recognised. To address this gap, we conducted a systematic review and meta-analysis of current literature.

Methods

We searched PubMed, Web of Science, Embase, Cochrane Library, and medRxiv for articles published up to 8 January 2023 on NMV-r in outpatients. At least two researchers screened articles, extracted data, and assessed the quality of selected studies. We evaluated the results via risk ratios (RRs) with 95% confidence intervals (CIs) and tested for heterogeneity using I² statistics.

Results

We included seven observational cohort studies comprising 224 238 vaccinated patients. According to our meta-analysis, NMV-r reduced 47% incidence of all-cause death or hospitalisation within 30 days for vaccinated patients (RR = 0.53; 95% CI = 0.40-0.70; I² = 81%). After excluding the most influential result by sensitivity analysis, NMV-r still reduced risk of all-cause death or hospitalisation by 38% (RR = 0.62; 95% CI = 0.56-0.69; I² = 0%). In our secondary outcome, NMV-r also showed its benefits in reducing all-cause death in vaccinated patients (RR = 0.40; 95% CI = 0.19-0.85; I² = 23%).

Conclusions

We found positive evidence for the use of NMV-r for vaccinated patients at high-risk of progression with mild to moderate COVID-19. However, large-scale RCTs are needed to confirm these findings.

Registration

PROSPERO CRD42023391349.

Laboratory Findings and Biomarkers in Long COVID: What Do We Know So Far? Insights into Epidemiology, Pathogenesis, Therapeutic Perspectives and Challenges

Long COVID (LC) encompasses a constellation of long-term symptoms experienced by at least 10% of people after the initial SARS-CoV-2 infection, and so far it has affected about 65 million people. The etiology of LC remains unclear; however, many pathophysiological pathways may be involved, including viral persistence; a chronic, low-grade inflammatory response; immune dysregulation and a defective immune response; the reactivation of latent viruses; autoimmunity; persistent endothelial dysfunction and coagulopathy; gut dysbiosis; hormonal and metabolic dysregulation; mitochondrial dysfunction; and autonomic nervous system dysfunction. There are no specific tests for the diagnosis of LC, and clinical features including laboratory findings and biomarkers may not specifically relate to LC. Therefore, it is of paramount importance to develop and validate biomarkers that can be employed for the prediction, diagnosis and prognosis of LC and its therapeutic response, although this effort may be hampered by challenges pertaining to the non-specific nature of the majority of clinical manifestations in the LC spectrum, small sample sizes of relevant studies and other methodological issues. Promising candidate biomarkers that are found in some patients are markers of systemic inflammation, including acute phase proteins, cytokines and chemokines; biomarkers reflecting SARS-CoV-2 persistence, the reactivation of herpesviruses and immune dysregulation; biomarkers of endotheliopathy, coagulation and fibrinolysis; microbiota alterations; diverse proteins and metabolites; hormonal and metabolic biomarkers; and cerebrospinal fluid biomarkers. At present, there are only two reviews summarizing relevant biomarkers; however, they do not cover the entire umbrella of current biomarkers, their link to etiopathogenetic mechanisms or the diagnostic work-up in a comprehensive manner. Herein, we aim to appraise and synopsize the available evidence on the typical laboratory manifestations and candidate biomarkers of LC, their classification based on pathogenetic mechanisms and the main LC symptomatology in the frame of the epidemiological and clinical aspects of the syndrome and furthermore assess limitations and challenges as well as potential implications in candidate therapeutic interventions.

Paxlovid (nirmatrelvir/ritonavir) effectiveness against hospitalization and death in N3C: A target trial emulation study

Importance

COVID-19 has placed a monumental burden on the health care system globally. Although no longer a public health emergency, there is still a pressing need for effective treatments to prevent hospitalization and death. Paxlovid (nirmatrelvir/ritonavir) is a promising and potentially effective antiviral that has received emergency use authorization by the U.S. FDA.

Objective

Determine real world effectiveness of Paxlovid nationwide and investigate disparities between treated and untreated eligible patients.

Design/Setting/Participants

Population-based cohort study emulating a target trial, using inverse probability weighted models to balance treated and untreated groups on baseline confounders. Participants were patients with a SARS-CoV-2 positive test or diagnosis (index) date between December 2021 and February 2023 selected from the National COVID Cohort Collaborative (N3C) database who were eligible for Paxlovid treatment. Namely, adults with at least one risk factor for severe COVID-19 illness, no contraindicated medical conditions, not using one or more strictly contraindicated medications, and not hospitalized within three days of index. From this cohort we identified patients who were treated with Paxlovid within 5 days of positive test or diagnosis (n = 98,060) and patients who either did not receive Paxlovid or were treated outside the 5-day window (n = 913,079 never treated; n = 1,771 treated after 5 days).

Exposures

Treatment with Paxlovid within 5 days of positive COVID-19 test or diagnosis.

Main Outcomes and Measures

Hospitalization and death in the 28 days following COVID-19 index date.

Results

A total of 1,012,910 COVID-19 positive patients at risk for severe COVID-19 were included, 9.7% of whom were treated with Paxlovid. Uptake varied widely by geographic region and timing, with top adoption areas near 50% and bottom near 0%. Adoption increased rapidly after EUA, reaching steady state by 6/2022. Participants who were treated with Paxlovid had a 26% (RR, 0.742; 95% CI, 0.689-0.812) reduction in hospitalization risk and 73% (RR, 0.269, 95% CI, 0.179-0.370) reduction in mortality risk in the 28 days following COVID-19 index date.

Conclusions/Relevance

Paxlovid is effective in preventing hospitalization and death in at-risk COVID-19 patients. These results were robust to a large number of sensitivity considerations.

Disclosure

The authors report no disclosures.

Key points

Question: Is treatment with Paxlovid (nirmatrelvir/ritonavir) associated with a reduction in 28-day hospitalization and mortality in patients at risk for severe COVID-19? Findings: In this multi-institute retrospective cohort study of 1,012,910 patients, Paxlovid treatment within 5 days after COVID-19 diagnosis reduced 28-day hospitalization and mortality by 26% and 73% respectively, compared to no treatment with Paxlovid within 5 days. Paxlovid uptake was low overall (9.7%) and highly variable. Meaning: In Paxlovid-eligible patients, treatment was associated with decreased risk of hospitalization and death. Results align with prior randomized trials and observational studies, thus supporting the real-world effectiveness of Paxlovid.

Efficacy of nirmatrelvir and ritonavir for post-acute COVID-19 sequelae beyond 3 months of SARS-CoV-2 infection

The effect of nirmatrelvir plus ritonavir (NMV-r) on post-acute COVID-19 sequelae beyond 3 months of SARS-CoV-2 infection remains unknown. This retrospective cohort study utilized data from the TriNetX Research Network. We identified nonhospitalized adult patients with COVID-19 receiving a diagnosis between January 1 and July 31, 2022. Propensity score matching (PSM) was used to create two matched cohorts: NMV-r and non-NMV-r groups, respectively. We measured the primary outcomes using a composite of all-cause emergency room (ER) visits or hospitalization and a composite of post-COVID-19 symptoms according to the WHO Delphi consensus, which also stated that post COVID-19 condition occurs usually 3 months from the onset of COVID-19, during the follow-up period between 90 days after the index diagnosis of COVID-19 and the end of follow-up (180 days). Initially, we identified 12 247 patients that received NMV-r within 5 days of diagnosis and 465 135 that did not. After PSM, 12 245 patients remained in each group. During the follow-up period, patients treated with NMV-r had a lower risk of all-cause hospitalization and ER visits compared with untreated patients (659 vs. 955; odds ratio [OR], 0.672; 95% confidence interval [CI], 0.607-0.745; p < 0.0001). However, the overall risk of post-acute COVID-19 symptoms did not significantly differ between the two groups (2265 vs. 2187; OR, 1.043; 95% CI, 0.978-1.114; p = 0.2021). The reduced risk of all-cause ER visits or hospitalization in the NMV-r group and the similarities in the risk of post-acute COVID-19 symptoms between the two groups were consistent in the subgroups stratified by sex, age, and vaccination status. Early NMV-r treatment of nonhospitalized patients with COVID-19 was associated with reduced risk of hospitalization and ER visits during the period of 90-180 days after diagnosis compared with no NMV-r treatment; however, post-acute COVID-19 symptoms and mortality risk did not differ significantly between the groups.

Target Trial Emulation Using Hospital-Based Observational Data: Demonstration and Application in COVID-19

Methodological biases are common in observational studies evaluating treatment effectiveness. The objective of this study is to emulate a target trial in a competing risks setting using hospital-based observational data. We extend established methodology accounting for immortal time bias and time-fixed confounding biases to a setting where no survival information beyond hospital discharge is available: a condition common to coronavirus disease 2019 (COVID-19) research data. This exemplary study includes a cohort of 618 hospitalized patients with COVID-19. We describe methodological opportunities and challenges that cannot be overcome applying traditional statistical methods. We demonstrate the practical implementation of this trial emulation approach via clone-censor-weight techniques. We undertake a competing risk analysis, reporting the cause-specific cumulative hazards and cumulative incidence probabilities. Our analysis demonstrates that a target trial emulation framework can be extended to account for competing risks in COVID-19 hospital studies. In our analysis, we avoid immortal time bias, time-fixed confounding bias, and competing risks bias simultaneously. Choosing the length of the grace period is justified from a clinical perspective and has an important advantage in ensuring reliable results. This extended trial emulation with the competing risk analysis enables an unbiased estimation of treatment effects, along with the ability to interpret the effectiveness of treatment on all clinically important outcomes.