COVID-19 "Rebound" associated with nirmatrelvir/ritonavir pre-hospital therapy

SARS-CoV-2 infection rebound among patients receiving antiviral agents, convalescent plasma, or no treatment: a systematic review with meta-analysis

BACKGROUND

There is some evidence showing rebound of COVID-19 infections in patients treated with nirmatrelvir-ritonavir between 2 and 8 days following cessation of the antiviral treatment. COVID-19 rebound is not unique to patients treated with nirmatrelvir-ritonavir, but is also observed in molnupiravir recipients, in patients who did not receive any antiviral treatment and in patients who received convalescent plasma (CP).

MATERIALS AND METHODS

This was a systematic review with meta-analysis of clinical trials evaluating rates of virologic and clinical rebound in COVID-19 patients receiving antiviral agents, CP or no treatment. Both randomized clinical trials and controlled cohort studies were considered. The methodological quality of trials was assessed using ROB-2 and ROBIN-1 checklists, and the GRADE approach.

RESULTS

Data were available from 16 trials. The occurrence of virologic rebound was more commonly observed among nirmatrelvir recipients than among untreated patients (relative risk [RR]=2.12; 95% confidence interval [CI]: 1.38-3.28; p=0.0007). No differences were observed in the occurrence of virologic rebound between nirmatrelvir-ritonavir and molnupiravir recipients (RR=1.01; 95% CI: 0.71-1.43). Similar rates of virologic rebounds were observed in molnupiravir recipients and untreated patients (RR=1.14; 95% CI: 0.81-1.6). One study in the pre-omicron period compared rates of virologic rebound between patients receiving standard of care with or without CP: no differences were observed between groups (RR=1.04; 95% CI: 0.55-1.99). Rates of clinical rebound were reported in seven trials, five evaluating nirmatrelvir-ritonavir and untreated patients, and two evaluating nirmatrelvir-ritonavir and molnupiravir recipients. No statistically significant differences between groups were observed. For all these comparisons, the certainty of the available evidence was graded as low or moderate.

DISCUSSION

Virologic rebound of COVID-19 infections appears to be mild and self-limited, and was observed more commonly in nirmatrelvir-ritonavir recipients than in untreated patients, but was also observed in patients treated with molnupiravir or CP.

A SONAR report on Nirmatrelvir/ritonavir-associated rebound COVID-19: Using new databases for evaluating new diseases

INTRODUCTION

In May 2022, the Centers for Disease Control and Prevention disseminated an alert advising that "a few" persons with Nirmatrelvir/ritonavir (NM/R)-associated rebound of COVID-19 infection had been identified. Three case reports appearing as pre-print postings described the first cases. Analyses in March 2023 by NM/R's manufacturer and the Food and Drug Administration (FDA) reported no association between NM/R and COVID-19 rebound in a large phase 3 randomized clinical trial. Our study evaluated if social media databases or electronically disseminated new articles might provide insights related to the putative new toxicity, NM/R-associated COVID-19 rebound.

METHODS

Information on NM/R-associated COVID-19 rebound cases was abstracted from preprint postings of non-peer-reviewed manuscripts, social media websites, electronically disseminated print and television media reports, a new FDA adverse event database for drugs that received Emergency Use Approval, and news articles in scientific journals.

RESULTS

Thirty-five persons experienced presumed or documented NM/R-associated COVID-19 rebound, based on information described in preprint services (n = 27), Twitter postings and related news articles (n = 7), and news articles without related Twitter reports (n = 1). These reports included information on dates of initial COVID-19 illness and rebound onset, COVID-19 testing, vaccine status, presentation, and outcome. A new FDA safety database identified 12,500 possible cases of this toxicity, but the quality of these data was poor. Preprint postings preceded peer-reviewed publications describing the same cases by four months. Social media websites including Instagram, Reddit, YouTube, the Center for Disease Control and Prevention's (CDC) Health Alert Network, CDC Twitter, and Facebook did not provide clinically meaningful information on individual cases.

CONCLUSION

Preprint services and Twitter facilitated identification of the largest case series of NM/R-associated COVID-19 rebound. The cases were reported in non-peer-reviewed media several weeks prior to the first peer-reviewed electronically disseminated publication of one person with this diagnosis.

Clinical rebound after treatment with nirmatrelvir/ritonavir in COVID-19

BACKGROUND

Nirmatrelvir/ritonavir (NM/r) is a safe and effective oral antiviral therapeutic used for treatment of mild-to-moderate COVID-19. Case reports described a clinical rebound syndrome whereby individuals experience a relapse of symptoms shortly after completing successful treatment. There is a lack of information on frequency of COVID-19 rebound after NM/r in routine clinical care, contributing factors, and clinical outcomes.

METHODS

We reviewed electronic medical records to verify COVID-19 diagnosis, symptoms, and treatment with NM/r from January-June 2022. We defined COVID-19 clinical rebound as clear improvement in symptoms followed by recurrence or worsening of symptoms within 30 days of a five-day course of NM/r.

RESULTS

We studied 268 adults with median age 57 (IQR 47, 68), 80% White race, 85% non-Hispanic ethnicity, 55% female, 80% vaccinated and boosted against SARS-CoV-2, and 68% with any co-morbidity. Sixteen (6.0%) of studied patients were determined to have COVID-19 clinical rebound. The median time from starting NM/r to rebound was 11 days (IQR 9, 13). Notable demographic and clinical factors with higher proportion (not statistically significant) among COVID-19 rebound patients were female sex (75% rebound vs. 54.5% no rebound), Black race (12.5% rebound vs. 4.9% no rebound), presence of at least one co-morbidity (81.3% rebound vs. 67.5% no rebound), and lack of prior SARS-CoV-2 infection (100% rebound vs. 92.9% no rebound). Only one patient (6.25%) was hospitalized after COVID-19 rebound.

CONCLUSIONS

COVID-19 clinical rebound after treatment with NM/r is mild with favorable outcomes and more common than previously reported from real-world clinical care studies.

COVID-19 clinical rebound after treatment with nirmatrelvir/ritonavir

Background

Nirmatrelvir/ritonavir (NM/r) is a safe and effective oral antiviral therapeutic used for treatment of mild-to-moderate COVID-19. Case reports described a clinical rebound syndrome whereby individuals experience a relapse of symptoms shortly after completing successful treatment. There is a lack of information on frequency of COVID-19 rebound after NM/r in routine clinical care, contributing factors, and clinical outcomes.

Methods

We reviewed electronic medical records to verify COVID-19 diagnosis, symptoms, and treatment with NM/r from January-June 2022. We defined COVID-19 clinical rebound as clear improvement in symptoms followed by recurrence or worsening of symptoms within 30 days of a five-day course of NM/r.

Results

We studied 268 adults with median age 57 (IQR 47, 68), 80% White race, 85% non-Hispanic ethnicity, 55% female, 80% vaccinated and boosted against SARS-CoV-2, and 68% with any co-morbidity. Sixteen (6.0%) of studied patients were determined to have COVID-19 clinical rebound. The median time from starting NM/r to rebound was 11 days (IQR 9, 13). Notable demographic and clinical factors with higher proportion (not statistically significant) among COVID-19 rebound patients were female sex (75% rebound vs 54.5% no rebound), Black race (12.5% rebound vs 4.9% no rebound), presence of at least one co-morbidity (81.3% rebound vs 67.5% no rebound), and lack of prior SARS-CoV-2 infection (100% rebound vs 92.9% no rebound). Only one patient (6.25%) was hospitalized after COVID-19 rebound.

Conclusions

COVID-19 clinical rebound after treatment with NM/r is mild with favorable outcomes and more common than previously reported from real-world clinical care studies.

Dynamic heterogeneity in COVID-19: Insights from a mathematical model

Critical illness, such as severe COVID-19, is heterogenous in presentation and treatment response. However, it remains possible that clinical course may be influenced by dynamic and/or random events such that similar patients subject to similar injuries may yet follow different trajectories. We deployed a mechanistic mathematical model of COVID-19 to determine the range of possible clinical courses after SARS-CoV-2 infection, which may follow from specific changes in viral properties, immune properties, treatment modality and random external factors such as initial viral load. We find that treatment efficacy and baseline patient or viral features are not the sole determinant of outcome. We found patients with enhanced innate or adaptive immune responses can experience poor viral control, resolution of infection or non-infectious inflammatory injury depending on treatment efficacy and initial viral load. Hypoxemia may result from poor viral control or ongoing inflammation despite effective viral control. Adaptive immune responses may be inhibited by very early effective therapy, resulting in viral load rebound after cessation of therapy. Our model suggests individual disease course may be influenced by the interaction between external and patient-intrinsic factors. These data have implications for the reproducibility of clinical trial cohorts and timing of optimal treatment.

Long COVID and its association with neurodegenerative diseases: pathogenesis, neuroimaging, and treatment

Corona Virus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has presented unprecedented challenges to the world. Changes after acute COVID-19 have had a significant impact on patients with neurodegenerative diseases. This study aims to explore the mechanism of neurodegenerative diseases by examining the main pathways of central nervous system infection of SARS-CoV-2. Research has indicated that chronic inflammation and abnormal immune response are the primary factors leading to neuronal damage and long-term consequences of COVID-19. In some COVID-19 patients, the concurrent inflammatory response leads to increased release of pro-inflammatory cytokines, which may significantly impact the prognosis. Molecular imaging can accurately assess the severity of neurodegenerative diseases in patients with COVID-19 after the acute phase. Furthermore, the use of FDG-PET is advocated to quantify the relationship between neuroinflammation and psychiatric and cognitive symptoms in patients who have recovered from COVID-19. Future development should focus on aggressive post-infection control of inflammation and the development of targeted therapies that target ACE2 receptors, ERK1/2, and Ca2+.

Natural products as a source of Coronavirus entry inhibitors

The COVID-19 pandemic has had a significant and lasting impact on the world. Four years on, despite the existence of effective vaccines, the continuous emergence of new SARS-CoV-2 variants remains a challenge for long-term immunity. Additionally, there remain few purpose-built antivirals to protect individuals at risk of severe disease in the event of future coronavirus outbreaks. A promising mechanism of action for novel coronavirus antivirals is the inhibition of viral entry. To facilitate entry, the coronavirus spike glycoprotein interacts with angiotensin converting enzyme 2 (ACE2) on respiratory epithelial cells. Blocking this interaction and consequently viral replication may be an effective strategy for treating infection, however further research is needed to better characterize candidate molecules with antiviral activity before progressing to animal studies and clinical trials. In general, antiviral drugs are developed from purely synthetic compounds or synthetic derivatives of natural products such as plant secondary metabolites. While the former is often favored due to the higher specificity afforded by rational drug design, natural products offer several unique advantages that make them worthy of further study including diverse bioactivity and the ability to work synergistically with other drugs. Accordingly, there has recently been a renewed interest in natural product-derived antivirals in the wake of the COVID-19 pandemic. This review provides a summary of recent research into coronavirus entry inhibitors, with a focus on natural compounds derived from plants, honey, and marine sponges.

Simnotrelvir as a potential treatment for COVID-19

INTRODUCTION

Simnotrelvir is a selective 3-chymotrypsin-like oral protease inhibitor with activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

AREAS COVERED

On 18 January 2024, results of a double-blind, randomized, placebo-controlled trial of simnotrelvir as a treatment for mild-to moderate COVID-19-were published, indicating the drug, when given in combination with ritonavir, shortened the time to resolution of symptoms.

EXPERT OPINION

Treatment options for most outpatients with mild-to-moderate COVID-19 are limited. The protease inhibitor nirmatrelvir in combination with ritonavir has proven effective in patients who are high risk for progression to severe COVID-19, but there are no approved therapies for standard-risk patients, who now comprise the majority of the population. Simnotrelvir appears to be effective in standard-risk patients, including those who have completed primary vaccination against COVID-19 and have received a booster dose. This manuscript examines the rationale for the development of simnotrelvir and explores how this drug may be used in the future to treat COVID-19.

Combination of spironolactone and sitagliptin improves clinical outcomes of outpatients with COVID-19: a prospective cohort study

BACKGROUND

There are evidences showing that sitagliptin and spironolactone can potentially improve the clinical outcomes of COVID-19 cases. In this observational study on acutely symptomatic outpatient COVID-19 cases, we investigated the effects of spironolactone and sitagliptin on the outcomes of the disease.

METHODS

This is a prospective, naturally randomized cohort study. We followed mild to moderate symptomatic COVID-19 patients, who were treated with either combination (spironolactone 100 mg daily and sitagliptin 100 mg daily) or standard (steroid, antiviral and/or supportive care) therapy up to 30 days. The primary outcome was hospitalization rate. The secondary outcomes included ER visit, duration of disease, and complications, such as hypoglycemia, low blood pressure or altered mental status.

RESULTS

Of the 206 patients referred to clinics randomly, 103 received standard therapy and 103 treated with combination therapy. There were no significant differences in baseline characteristics, except for slightly higher clinical score in control group (6.92 ± 4.01 control, 4.87 ± 2.92 combination; P < 0.0001). Treatment with combination therapy was associated with lower admission rate (5.8% combination, 22.3% control; P = 0.0011), ER visits (7.8% combination, 23.3% control; P = 0.0021) and average duration of symptoms (6.67 ± 2.30 days combination, 18.71 ± 6.49 days control; P ≤ 0.0001).

CONCLUSIONS

The combination of sitagliptin and spironolactone reduced duration of COVID infection and hospital visits better than standard therapeutic approaches in outpatients with COVID-19. The effects of combination of sitagliptin and spironolactone in COVID-19 patients should be further verified in a double-blind, randomized, placebo-controlled trial.

SARS-CoV-2 Rebound With and Without Use of COVID-19 Oral Antivirals

Early treatment with a first-line therapy (nirmatrelvir/ritonavir [Paxlovid] or remdesivir) or second-line therapy (molnupiravir) prevents hospitalization and death among patients with mild-to-moderate COVID-19 who are at risk for severe disease and is recommended by the National Institutes of Health COVID-19 Treatment Guidelines. On May 25, 2023, the Food and Drug Administration approved nirmatrelvir/ritonavir for treatment of adults at high risk for severe disease. Although antiviral therapies are widely available, they are underutilized, possibly because of reports of SARS-CoV-2 rebound after treatment. To enhance current understanding of rebound, CDC reviewed SARS-CoV-2 rebound studies published during February 1, 2020- November 29, 2023. Overall, seven of 23 studies that met inclusion criteria, one randomized trial and six observational studies, compared rebound for persons who received antiviral treatment with that for persons who did not receive antiviral treatment. In four studies, including the randomized trial, no statistically significant difference in rebound rates was identified among persons receiving treatment and those not receiving treatment. Depending on the definition used, the prevalence of rebound varied. No hospitalizations or deaths were reported among outpatients who experienced rebound, because COVID-19 signs and symptoms were mild. Persons receiving antiviral treatment might be at higher risk for rebound compared with persons not receiving treatment because of host factors or treatment-induced viral suppression early in the course of illness. The potential for rebound should not deter clinicians from prescribing lifesaving antiviral treatments when indicated to prevent morbidity and mortality from COVID-19.

Oral Nirmatrelvir and Ritonavir for Coronavirus Disease 2019 in Vaccinated, Nonhospitalized Adults Aged 18-50 Years

BACKGROUND

The effects of nirmatrelvir/ritonavir (NMV/r [Paxlovid]) on coronavirus disease 2019 (COVID-19) outcomes in younger vaccinated adults are unclear. The objective of this study was to assess if NMV/r use in vaccinated adults aged ≤50 years is associated with improved outcomes and to identify beneficial and nonbeneficial subgroups.

METHODS

In this cohort study, we generated 2 propensity-matched cohorts of 2547 patients from an 86 119-person cohort assembled from the TriNetX database. Patients in 1 cohort received NMV/r, and patients in the matched control cohort did not. The main outcome was composite of all-cause emergency department visits, hospitalization, and mortality.

RESULTS

The composite outcome was detected in 4.9% of the NMV/r cohort and 7.0% of the non-NMV/r cohort (odds ratio, 0.683 [95% confidence interval, .540-.864]; P = .001), indicating a 30% relative risk reduction. The number needed to treat (NNT) for the primary outcome was 47. Subgroup analyses found significant associations for patients with cancer (NNT = 45), cardiovascular disease (NNT = 30), and both conditions (NNT = 16). No benefit was found for patients with only chronic lower respiratory disorders (asthma/chronic obstructive pulmonary disease [COPD]) or without serious comorbidities. Thirty-two percent of NMV/r prescriptions in the overall database were for 18- to 50-year-olds.

CONCLUSIONS

NMV/r use in vaccinated adults aged 18-50 years, especially with serious comorbidities, was associated with reduced all-cause hospital visits, hospitalization, and mortality in the first 30 days of COVID-19 illness. However, NMV/r in patients without significant comorbidities or with only asthma/COPD had no association of benefit. Therefore, identifying high-risk patients should be a priority and overprescription should be avoided.

Nirmatrelvir/ritonavir (Paxlovid®): French pharmacovigilance survey 2022

INTRODUCTION

Nirmatrelvir/ritonavir (Paxlovid®) is currently one of the few therapeutic options for coronavirus disease 2019 (COVID-19) curative treatment in non-oxygen-requiring adult patients at-high risk of progressing to severe disease. This recently approved boosted antiviral therapy presents a significant risk of drug-drug interactions (DDI). As part of the enhanced surveillance program in France for COVID-19 drugs and vaccines, the French national pharmacovigilance database (BNPV [base nationale de pharmacovigilance]) was queried in order to better characterize the drug safety profile, with a special focus on DDI. The aim of the study was to describe the adverse drug reactions reported through the BNPV.

METHOD

All nirmatrelvir/ritonavir reports validated in the BNPV from the first authorization in France (January, 20th 2022) to December, 3rd 2022 (date of the query) were considered. An analysis of the scientific literature (PubMed®) and from the WHO pharmacovigilance database (Vigibase) was also performed.

RESULTS

Over this period (11 months), 228 reports (40% of serious reports) were registered with a sex ratio of 1.9 female/1 male and a mean age of 66 years old. DDI reports account for more than 13% of reports (n=30) and were mainly related to immunosuppressive drugs overexposure (n=16). A total of 10/228 reports with fatal outcomes were reported in complex clinical settings. The main reported unexpected adverse drug reaction (ADRs) were high blood pressure (n=7), confusion (n=5), acute kidney injuries (AKI, n=7) and various skin reactions (n=22). Apart from situations of disease recurrence (not found in this analysis), data from Pubmed® and Vigibase also reported the above-mentioned events of interest.

CONCLUSION

Overall, this analysis shows that nirmatrelvir/ritonavir safety profile was conform to current summary of product characteristics (SmPC). The main concern was the risk of DDI. Therefore, SmPC and expert recommendations should be systematically consulted before initiation of this antiviral, which is particularly indicated in polypharmacy patients. A case-by-case multidisciplinary approach including a clinical pharmacologist is required in these complex situations. Blood pressure elevation, confusion, cutaneous reactions and AKIs were the main unexpected ADRs of interest to follow, but need to be confirmed with a qualitative approach over time and new reports.

Paxlovid as a potential treatment for long COVID

INTRODUCTION

On 31 July 2023, the United States Department of Health and Human Services announced the formation of the Office of Long COVID Research and Practice and the United States National Institutes of Health opened enrollment for RECOVER-Vital, a randomized study to evaluate new treatment options for long Coronavirus (long COVID).

AREAS COVERED

The RECOVER Initiative is a $1.15 billion research platform intended to describe, categorize, treat, and prevent long-term symptoms following infection by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‑CoV‑2), the virus that causes Coronavirus (COVID-19). More than 200 symptoms have been associated with long COVID, potentially affecting nearly all body systems, and current estimates suggest that between 7 million and 23 million Americans have developed long COVID. However, there are no approved treatments for this condition.

EXPERT OPINION

The first prospective, randomized study of the RECOVER research initiative, RECOVER-Vital, will evaluate the SARS-CoV-2 antiviral nirmatrelvir/ritonavir (Paxlovid) as a potential treatment for long COVID. This manuscript explores what is known about Paxlovid to treat and prevent long COVID and examines the rationale for addressing this condition with an antiviral agent.

Post-marketing safety concerns with nirmatrelvir: A disproportionality analysis of spontaneous reports submitted to the FDA Adverse Event Reporting System

AIMS

Nirmatrelvir is an antiviral drug with a novel mechanism of action, targeting the 3-CL protease, and is used in the treatment of COVID-19. However, the potential side effects have not yet been fully studied. The aim of this study was to identify potential safety signals of nirmatrelvir by analysing post-marketing safety data based on the largest publicly available worldwide pharmacovigilance database.

METHODS

We analysed nirmatrelvir adverse events to identify and characterize relevant safety signals based on the FDA Adverse Event Reporting System database in 2022. The case/non-case approach was used to estimate the reporting odds ratio (ROR) and information component (IC) with relevant confidence intervals (95% CI) for adverse events (AEs) that numbered 4 or more.

RESULTS

A total of 26 846 cases were included. Disease recurrence (ROR [95% CI] = 413.2 [395.6-431.59]), dysgeusia (ROR [95% CI] = 110.84 [106.04-115.85]), anosmia (ROR [95% CI] = 15.21 [12.76-18.11]), ageusia (ROR [95% CI] = 9.80 [8.50-11.3]) and urticaria (ROR [95% CI] = 1.91 [1.69-2.17]) were the main safety signals. In addition, abdominal pain upper and skin toxicity were two specific safety signals of nirmatrelvir. In the pregnant population, there was a significant increased ROR for life-threatening conditions (ROR [95% CI] = 8.00 [1.77-36.20]).

CONCLUSIONS

Our study identified that the main and specific safety signals of nirmatrelvir were disease recurrence, dysgeusia, abdominal pain upper and skin toxicity. Clinicians and pharmacists should be vigilant of these AEs, although differentiating between COVID-19 symptoms and AEs can be challenging. Notably, a potential safety concern of nirmatrelvir should be a warning based on a small number of events in the pregnant population. However, the available data are insufficient, and further continued pharmacovigilance and surveillance is needed to fully understand this issue.

Benefits of near-universal vaccination and treatment access to manage COVID-19 burden in the United States

BACKGROUND

As we continue the fourth year of the COVID-19 epidemic, SARS-CoV-2 infections still cause high morbidity and mortality in the United States. During 2020-2022, COVID-19 was one of the leading causes of death in the United States and by far the leading cause among infectious diseases. Vaccination uptake remains low despite this being an effective burden reducing intervention. The development of COVID-19 therapeutics provides hope for mitigating severe clinical outcomes. This modeling study examines combined strategies of vaccination and treatment to reduce the burden of COVID-19 epidemics over the next decade.

METHODS

We use a validated mathematical model to evaluate the reduction of incident cases, hospitalized cases, and deaths in the United States through 2033 under various levels of vaccination and treatment coverage. We assume that future seasonal transmission patterns for COVID-19 will be similar to those of influenza virus and account for the waning of infection-induced immunity and vaccine-induced immunity in a future with stable COVID-19 dynamics. Due to uncertainty in the duration of immunity following vaccination or infection, we consider three exponentially distributed waning rates, with means of 365 days (1 year), 548 days (1.5 years), and 730 days (2 years). We also consider treatment failure, including rebound frequency, as a possible treatment outcome.

RESULTS

As expected, universal vaccination is projected to eliminate transmission and mortality. Under current treatment coverage (13.7%) and vaccination coverage (49%), averages of 81,000-164,600 annual reported deaths, depending on duration of immunity, are expected by the end of this decade. Annual mortality in the United States can be reduced below 50,000 per year with 52-80% annual vaccination coverage and below 10,000 annual deaths with 59-83% annual vaccination coverage, depending on duration of immunity. Universal treatment reduces hospitalizations by 88.6% and deaths by 93.1% under current vaccination coverage. A reduction in vaccination coverage requires a comparatively larger increase in treatment coverage in order for hospitalization and mortality levels to remain unchanged.

CONCLUSIONS

Adopting universal vaccination and universal treatment goals in the United States will likely lead to a COVID-19 mortality burden below 50,000 deaths per year, a burden comparable to that of influenza virus.

Proxalutamide reduces SARS-CoV-2 infection and associated inflammatory response

Early in the COVID-19 pandemic, data suggested that males had a higher risk of developing severe disease and that androgen deprivation therapy might be associated with protection. Combined with the fact that TMPRSS2 (transmembrane serine protease 2), a host entry factor for the SARS-CoV-2 virus, was a well-known androgen-regulated gene, this led to an upsurge of research investigating androgen receptor (AR)-targeting drugs. Proxalutamide, an AR antagonist, was shown in initial clinical studies to benefit COVID-19 patients; however, further validation is needed as one study was retracted. Due to continued interest in proxalutamide, which is in phase 3 trials, we examined its ability to impact SARS-CoV-2 infection and downstream inflammatory responses. Proxalutamide exerted similar effects as enzalutamide, an AR antagonist prescribed for advanced prostate cancer, in decreasing AR signaling and expression of TMPRSS2 and angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 receptor. However, proxalutamide led to degradation of AR protein, which was not observed with enzalutamide. Proxalutamide inhibited SARS-CoV-2 infection with an IC50 value of 97 nM, compared to 281 nM for enzalutamide. Importantly, proxalutamide inhibited infection by multiple SARS-CoV-2 variants and synergized with remdesivir. Proxalutamide protected against cell death in response to tumor necrosis factor alpha and interferon gamma, and overall survival of mice was increased with proxalutamide treatment prior to cytokine exposure. Mechanistically, we found that proxalutamide increased levels of NRF2, an essential transcription factor that mediates antioxidant responses, and decreased lung inflammation. These data provide compelling evidence that proxalutamide can prevent SARS-CoV-2 infection and cytokine-induced lung damage, suggesting that promising clinical data may emerge from ongoing phase 3 trials.

The Coronavirus Disease 2019 Rebound Study: A Prospective Cohort Study to Evaluate Viral and Symptom Rebound Differences in Participants Treated With Nirmatrelvir Plus Ritonavir Versus Untreated Controls

BACKGROUND

The uptake of nirmatrelvir plus ritonavir (NPR) in patients with coronavirus disease 2019 (COVID-19) has been limited by concerns around the rebound phenomenon despite the scarcity of evidence around its epidemiology. The purpose of this study was to prospectively compare the epidemiology of rebound in NPR-treated and untreated participants with acute COVID-19 infection.

METHODS

We designed a prospective, observational study in which participants who tested positive for COVID-19 and were clinically eligible for NPR were recruited to be evaluated for either viral or symptom clearance and rebound. Participants were assigned to the treatment or control group based on their decision to take NPR. Following initial diagnosis, both groups were provided 12 rapid antigen tests and asked to test on a regular schedule for 16 days and answer symptom surveys. Viral rebound based on test results and COVID-19 symptom rebound based on patient-reported symptoms were evaluated.

RESULTS

Viral rebound incidence was 14.2% in the NPR treatment group (n = 127) and 9.3% in the control group (n = 43). Symptom rebound incidence was higher in the treatment group (18.9%) compared to controls (7.0%). There were no notable differences in viral rebound by age, gender, preexisting conditions, or major symptom groups during the acute phase or at the 1-month interval.

CONCLUSIONS

This preliminary report suggests that rebound after clearance of test positivity or symptom resolution is higher than previously reported. However, notably we observed a similar rate of rebound in both the NPR treatment and control groups. Large studies with diverse participants and extended follow-up are needed to better understand the rebound phenomena.

Viral burden rebound in hospitalised patients with COVID-19 receiving oral antivirals in Hong Kong: a population-wide retrospective cohort study

BACKGROUND

Viral rebound after nirmatrelvir-ritonavir treatment has implications for the clinical management and isolation of patients with COVID-19. We evaluated an unselected, population-wide cohort to identify the incidence of viral burden rebound and associated risk factors and clinical outcomes.

METHODS

We did a retrospective cohort study of hospitalised patients with a confirmed diagnosis of COVID-19 in Hong Kong, China, for an observation period from Feb 26 to July 3, 2022 (during the omicron BA.2.2 variant wave). Adult patients (age ≥18 years) admitted 3 days before or after a positive COVID-19 test were selected from medical records held by the Hospital Authority of Hong Kong. We included patients with non-oxygen-dependent COVID-19 at baseline receiving either molnupiravir (800 mg twice a day for 5 days), nirmatrelvir-ritonavir (nirmatrelvir 300 mg with ritonavir 100 mg twice a day for 5 days), or no oral antiviral treatment (control group). Viral burden rebound was defined as a reduction in cycle threshold (Ct) value (≥3) on quantitative RT-PCR test between two consecutive measurements, with such decrease sustained in an immediately subsequent Ct measurement (for those patients with ≥3 Ct measurements). Logistic regression models were used to identify prognostic factors for viral burden rebound, and to assess associations between viral burden rebound and a composite clinical outcome of mortality, intensive care unit admission, and invasive mechanical ventilation initiation, stratified by treatment group.

FINDINGS

We included 4592 hospitalised patients with non-oxygen-dependent COVID-19 (1998 [43·5%] women and 2594 [56·5%] men). During the omicron BA.2.2 wave, viral burden rebound occurred in 16 of 242 patients (6·6% [95% CI 4·1-10·5]) receiving nirmatrelvir-ritonavir, 27 of 563 (4·8% [3·3-6·9]) receiving molnupiravir, and 170 of 3787 (4·5% [3·9-5·2]) in the control group. The incidence of viral burden rebound did not differ significantly across the three groups. Immunocompromised status was associated with increased odds of viral burden rebound, regardless of antiviral treatment (nirmatrelvir-ritonavir: odds ratio [OR] 7·37 [95% CI 2·56-21·26], p=0·0002; molnupiravir: 3·05 [1·28-7·25], p=0·012; control: 2·21 [1·50-3·27], p<0·0001). Among patients receiving nirmatrelvir-ritonavir, the odds of viral burden rebound were higher in those aged 18-65 years (vs >65 years; 3·09 [1·00-9·53], p=0·050), those with high comorbidity burden (score >6 on the Charlson Comorbidity Index; 6·02 [2·09-17·38], p=0·0009), and those concomitantly taking corticosteroids (7·51 [1·67-33·82], p=0·0086); whereas the odds were lower in those who were not fully vaccinated (0·16 [0·04-0·67], p=0·012). In patients receiving molnupiravir, those aged 18-65 years (2·68 [1·09-6·58], p=0·032) or on concomitant corticosteroids (3·11 [1·23-7·82], p=0·016) had increased odds of viral burden rebound. We found no association between viral burden rebound and occurrence of the composite clinical outcome from day 5 of follow-up (nirmatrelvir-ritonavir: adjusted OR 1·90 [0·48-7·59], p=0·36; molnupiravir: 1·05 [0·39-2·84], p=0·92; control: 1·27 [0·89-1·80], p=0·18).

INTERPRETATION

Viral burden rebound rates are similar between patients with antiviral treatment and those without. Importantly, viral burden rebound was not associated with adverse clinical outcomes.

FUNDING

Health and Medical Research Fund, Health Bureau, The Government of the Hong Kong Special Administrative Region, China.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

A mathematical model of SARS-CoV-2 immunity predicts paxlovid rebound

Nirmatrelvir/ritonavir (Paxlovid), an oral antiviral medication targeting SARS-CoV-2, remains an important treatment for COVID-19. Initial studies of nirmatrelvir/ritonavir were performed in SARS-CoV-2 unvaccinated patients without prior confirmed SARS-CoV-2 infection; however, most individuals have now either been vaccinated and/or have experienced SARS-CoV-2 infection. After nirmatrelvir/ritonavir became widely available, reports surfaced of "Paxlovid rebound," a phenomenon in which symptoms (and SARS-CoV-2 test positivity) would initially resolve, but after finishing treatment, symptoms and test positivity would return. We used a previously described parsimonious mathematical model of immunity to SARS-CoV-2 infection to model the effect of nirmatrelvir/ritonavir treatment in unvaccinated and vaccinated patients. Model simulations show that viral rebound after treatment occurs only in vaccinated patients, while unvaccinated (SARS-COV-2 naïve) patients treated with nirmatrelvir/ritonavir do not experience any rebound in viral load. This work suggests that an approach combining parsimonious models of the immune system could be used to gain important insights in the context of emerging pathogens.

Real-world use of nirmatrelvir-ritonavir in outpatients with COVID-19 during the era of omicron variants including BA.4 and BA.5 in Colorado, USA: a retrospective cohort study

BACKGROUND

Nirmatrelvir is a protease inhibitor with in-vitro activity against SARS-CoV-2, and ritonavir-boosted nirmatrelvir can reduce the risk of progression to severe COVID-19 among individuals at high risk infected with delta and early omicron variants. However, less is known about the effectiveness of nirmatrelvir-ritonavir during more recent BA.2, BA2.12.1, BA.4, and BA.5 omicron variant surges. We used our real-world data platform to evaluate the effect of nirmatrelvir-ritonavir treatment on 28-day hospitalisation, mortality, and emergency department visits among outpatients with early symptomatic COVID-19 during a SARS-CoV-2 omicron (BA.2, BA2.12.1, BA.4, and BA.5) predominant period in Colorado, USA.

METHODS

We did a propensity-matched, retrospective, observational cohort study of non-hospitalised adult patients infected with SARS-CoV-2 between March 26 and Aug 25, 2022, using records from a statewide health system in Colorado. We obtained data from the electronic health records of University of Colorado Health, the largest health system in Colorado, with 13 hospitals and 141 000 annual hospital admissions, and with numerous ambulatory sites and affiliated pharmacies around the state. Included patients had a positive SARS-CoV-2 test or nirmatrelvir-ritonavir medication order. Exclusion criteria were an order for or administration of other SARS-CoV-2 treatments within 10 days of a positive SARS-CoV-2 test, hospitalisation at the time of positive SARS-CoV-2 test, and positive SARS-CoV-2 test more than 10 days before a nirmatrelvir-ritonavir order. We propensity score matched patients treated with nirmatrelvir-ritonavir with untreated patients. The primary outcome was 28-day all-cause hospitalisation.

FINDINGS

Among 28 167 patients infected with SARS-CoV-2 between March 26 and Aug 25, 2022, 21 493 met the study inclusion criteria. 9881 patients received treatment with nirmatrelvir-ritonavir and 11 612 were untreated. Nirmatrelvir-ritonavir treatment was associated with reduced 28-day all-cause hospitalisation compared with no antiviral treatment (61 [0·9%] of 7168 patients vs 135 [1·4%] of 9361 patients, adjusted odds ratio (OR) 0·45 [95% CI 0·33-0·62]; p<0·0001). Nirmatrelvir-ritonavir treatment was also associated with reduced 28-day all-cause mortality (two [<0·1%] of 7168 patients vs 15 [0·2%] of 9361 patients; adjusted OR 0·15 [95% CI 0·03-0·50]; p=0·0010). Using subsequent emergency department visits as a surrogate for clinically significant relapse, we observed a decrease after nirmatrelvir-ritonavir treatment (283 [3·9%] of 7168 patients vs 437 [4·7%] of 9361 patients; adjusted OR 0·74 [95% CI 0·63-0·87]; p=0·0002).

INTERPRETATION

Real-world evidence reported during a BA.2, BA2.12.1, BA.4, and BA.5 omicron surge showed an association between nirmatrelvir-ritonavir treatment and reduced 28-day all-cause hospitalisation, all-cause mortality, and visits to the emergency department. With results that are among the first to suggest effectiveness of nirmatrelvir-ritonavir for non-hospitalised patients during an omicron period inclusive of BA.4 and BA.5 subvariants, these data support nirmatrelvir-ritonavir as an ongoing first-line treatment for adults acutely infected with SARS-CoV-2.

FUNDING

US National Institutes of Health.

Central Nervous System Neuroimmunologic Complications of COVID-19

Autoimmune disorders of the central nervous system following COVID-19 infection include multiple sclerosis (MS), neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein antibody-associated disease, autoimmune encephalitis, acute disseminated encephalomyelitis, and other less common neuroimmunologic disorders. In general, these disorders are rare and likely represent postinfectious phenomena rather than direct consequences of the SARS-CoV-2 virus itself. The impact of COVID-19 infection on patients with preexisting neuroinflammatory disorders depends on both the disorder and disease-modifying therapy use. Patients with MS do not have an increased risk for severe COVID-19, though patients on anti-CD20 therapies may have worse clinical outcomes and attenuated humoral response to vaccination. Data are limited for other neuroinflammatory disorders, but known risk factors such as older age and medical comorbidities likely play a role. Prophylaxis and treatment for COVID-19 should be considered in patients with preexisting neuroinflammatory disorders at high risk for developing severe COVID-19.

VV116 as a potential treatment for COVID-19

INTRODUCTION

VV116 is a chemically-modified version of the antiviral remdesivir with oral bioavailability and potent activity against SARS-CoV-2.

AREAS COVERED

The optimal treatment of standard-risk outpatients who develop mild-to-moderate COVID-19 is controversial. While several therapeutic are currently recommended, including nirmatrelvir-ritonavir (Paxlovid), molnupiravir, and remdesivir, these treatments have substantial drawbacks, including drug-drug interactions and questionable efficacy in vaccinated adults. Novel therapeutic options are urgently needed.

EXPERT OPINION

On 28 December 2022, a phase 3, observer-blinded, randomized trial was published evaluating 771 symptomatic adults with mild-to-moderate COVID-19 with a high risk of progression to severe disease. Participants were assigned to receive a 5-day course of either Paxlovid)\, which is recommended by the World Health Organization for treating mild-to-moderate COVID-19, or VV116 and the primary end point was the time to sustained clinical recovery through day 28. Among study subjects, VV116 was found to be noninferior to Paxlovid with respect to the time to sustained clinical recovery and with fewer safety concerns. This manuscript examines what is known about VV116 and explores how this novel treatment option may be used in the future to address the ongoing SARS-CoV-2 pandemic.

Factors associated with viral rebound among COVID-19 patients receiving oral antivirals

BACKGROUND

COVID-19 rebound is usually reported among patients experiencing concurrent symptomatic and viral rebound. But longitudinal viral RT-PCR results from early stage to rebound of COVID-19 was less characterized. Further, identifying the factors associated with viral rebound after nirmatrelvir-ritonavir (NMV/r) and molnupiravir may expand understanding of COVID-19 rebound.

METHODS

We retrospectively analyzed clinical data and sequential viral RT-PCR results from COVID-19 patients receiving oral antivirals between April and May, 2022. Viral rebound was defined by the degree of viral load increase (ΔCt ≥ 5 units).

RESULTS

A total of 58 and 27 COVID-19 patients taking NMV/r and molnupiravir, respectively, were enrolled. Patients receiving NMV/r were younger, had fewer risk factors for disease progression and faster viral clearance rate compared to those receiving molnupiravr (All P < 0.05). The overall proportion of viral rebound (n = 11) was 12.9%, which was more common among patients receiving NMV/r (10 [17.2%] vs. 1 [3.7%], P = 0.16). Of them, 5 patients experienced symptomatic rebound, suggesting the proportion of COVID-19 rebound was 5.9%. The median interval to viral rebound was 5.0 (interquartile range, 2.0-8.0) days after completion of antivirals. Initial lymphopenia (<0.8 × 10⁹/L) was associated with viral rebound among overall population (adjusted odds ratio [aOR], 5.34; 95% confidence interval [CI], 1.33-21.71), and remained significant (aOR, 4.50; 95% CI, 1.05-19.25) even when patients receiving NMV/r were considered.

CONCLUSION

Our data suggest viral rebound after oral antivirals may be more commonly observed among lymphopenic individuals in the context of SARS-CoV-2 Omicron BA.2 variant.

The immune paradox of SARS-CoV-2: Lymphocytopenia and autoimmunity evoking features in COVID-19 and possible treatment modalities

SARS-CoV-2 causes multiorgan damage to vital organs and tissue that are known to be due to a combination of tissue tropisms and cytokine-mediated damage that it can incite in COVID-19. The effects of SARS-Co-2 on the lymphocytes and therefore on the immune response have attracted attention recently in COVID-19 to understand its effects in causing a chronic state of ongoing infection with Long-COVID. The associated lymphopaenia and autoimmune disease state, which is an apparent paradox, needs to be researched to dissect possible mechanisms underlying this state. This paper attempts to unravel the aforesaid immune paradox effects of SARS-CoV-2 on the lymphocytes and discusses appropriate treatment modalities with antiviral drugs and nutraceuticals which could prove virucidal in SARS-CoV-2 seeding monocytes and lymphocytes in patients with COVID-19 and Long-COVID. Importantly it proposes a new in vitro treatment modality of immune regulating cells that can help patients fight the lymphopaenia associated with COVID-19 and Long-COVID.

Outcomes with and without outpatient SARS-CoV-2 treatment for patients with COVID-19 and systemic autoimmune rheumatic diseases: a retrospective cohort study

Background

Some patients with systemic autoimmune rheumatic disease and immunosuppression might still be at risk of severe COVID-19. The effect of outpatient SARS-CoV-2 treatments on COVID-19 outcomes among patients with systemic autoimmune rheumatic disease is unclear. We aimed to evaluate temporal trends, severe outcomes, and COVID-19 rebound among patients with systemic autoimmune rheumatic disease and COVID-19 who received outpatient SARS-CoV-2 treatment compared with those who did not receive outpatient treatment.

Methods

We did a retrospective cohort study at Mass General Brigham Integrated Health Care System, Boston, MA, USA. We included patients aged 18 years or older with a pre-existing systemic autoimmune rheumatic disease, who had COVID-19 onset between Jan 23 and May 30, 2022. We identified COVID-19 by positive PCR or antigen test (index date defined as the date of first positive test) and systemic autoimmune rheumatic diseases using diagnosis codes and immunomodulator prescription. Outpatient SARS-CoV-2 treatments were confirmed by medical record review. The primary outcome was severe COVID-19, defined as hospitalisation or death within 30 days after the index date. COVID-19 rebound was defined as documentation of a negative SARS-CoV-2 test after treatment followed by a newly positive test. The association of outpatient SARS-CoV-2 treatment versus no outpatient treatment with severe COVID-19 outcomes was assessed using multivariable logistic regression.

Findings

Between Jan 23 and May 30, 2022, 704 patients were identified and included in our analysis (mean age 58·4 years [SD 15·9]; 536 [76%] were female and 168 [24%] were male, 590 [84%] were White and 39 [6%] were Black, and 347 [49%] had rheumatoid arthritis). Outpatient SARS-CoV-2 treatments increased in frequency over calendar time (p<0·0001). A total of 426 (61%) of 704 patients received outpatient treatment (307 [44%] with nirmatrelvir-ritonavir, 105 [15%] with monoclonal antibodies, five [1%] with molnupiravir, three [<1%] with remdesivir, and six [1%] with combination treatment). There were nine (2·1%) hospitalisations or deaths among 426 patients who received outpatient treatment compared with 49 (17·6%) among 278 who did not receive outpatient treatment (odds ratio [adjusted for age, sex, race, comorbidities, and kidney function] 0·12, 95% CI 0·05-0·25). 25 (7·9%) of 318 patients who received oral outpatient treatment had documented COVID-19 rebound.

Interpretation

Outpatient treatment was associated with lower odds of severe COVID-19 outcomes compared with no outpatient treatment. These findings highlight the importance of outpatient SARS-CoV-2 treatment for patients with systemic autoimmune rheumatic disease and COVID-19 and the need for further research on COVID-19 rebound.

Funding

None.

Nirmatrelvir and COVID-19: development, pharmacokinetics, clinical efficacy, resistance, relapse, and pharmacoeconomics

Nirmatrelvir/ritonavir (N/R) is one of the most effective antiviral drugs against SARS-CoV-2. The preclinical development, pharmacodynamics and pharmacokinetics of N/R are reviewed herein. Randomized clinical trials have been conducted exclusively with pre-Omicron variants of concern, but in vitro studies show that efficacy against all Omicron sublineages is preserved, as confirmed by post-marketing observational studies. Nevertheless, investigations of large viral genome repositories have shown that mutation in the main protease causing resistance to N/R are increasingly frequent. In addition, virological and clinical rebounds after N/R discontinuation have been reported in immunocompetent patients. This finding is of concern when translated to immunocompromised patients, in whom N/R efficacy has not been formally investigated in clinical trials. Economical sustainability and perspectives for this therapeutic arena are discussed.

Coronavirus disease 2019 rebounds following nirmatrelvir/ritonavir treatment

Nirmatrelvir/ritonavir (NMV-r) is an effective anti-SARS-CoV-2 agent and has been recommended in the treatment of nonhospitalized patients with COVID-19. In rare occasions, some patients experience virologic and symptomatic rebound after initial resolution, which we call COVID-19 rebound after NMV-r. Although COVID rebound can also occur after molnupiravir treatment or even no antiviral treatment, we have more serious concern about the rebound after NMV-r, which remains the most effective antiviral. Due to a lack of information about its frequency, mechanism, outcomes, and management, we conducted this review to provide comprehensive and updated information to address these questions. Based on the limited evidence, the incidence of COVID-19 rebound after NMV-r was less than 2%, and most cases developed 5-15 days after initiating NMV-r treatment. Almost all reported cases had mild symptoms, and the clinical condition gradually subsided without additional treatment. Overall, the clinical outcome was favorable, and only a small number of patients required emergency department visits or hospitalization. Regarding virologic rebound, culturable SARS-CoV-2 with possible transmission was observed, so re-isolation may be needed.

The effect of nirmatrelvir-ritonavir on viral clearance and length of hospital stay in patients infected with SARS-CoV-2 omicron variants

BACKGROUND

The pandemic of coronavirus disease 2019 (COVID-19) has caused heavy burdens on national healthcare systems. Nirmatrelvir-ritonavir (Paxlovid) may be one of the most promising therapeutic drugs, with reports of up to 89% reduction rates in hospitalization risk and death among patients with mild-to-moderate COVID-19 who are at risk of developing severe disease. However, limited studies have investigated the effects of this class of drugs on viral clearance and length of hospital stay.

METHODS

In this study, we retrospectively analyzed the characteristics of patients infected with the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and investigated the effects of oral nirmatrelvir-ritonavir on viral clearance and length of hospital stay in mild-to-moderate COVID-19 patients at high risk for progression to severe disease.

RESULTS

The median SARS-CoV-2 negative conversion time was 16 (13-20) versus 13 (10-16) days (control group versus nirmatrelvir-ritonavir group, p < 0.001), the median length of hospital stay was 13 (10-16) versus 12 (13-14) days (control group versus nirmatrelvir-ritonavir group, p = 0.01), and the SARS-CoV-2 negative conversion time and length of hospital stay were significantly shorter in the nirmatrelvir-ritonavir group than in the control group. When controlling for hypertension, chronic kidney disease, severity status of COVID-19, use of antibiotic agent, and COVID-19 vaccine received, multiple stepwise linear regression analysis showed that nirmatrelvir-ritonavir treatment was negatively associated with the SARS-CoV-2 negative conversion time and length of hospital stay.

CONCLUSION

Nirmatrelvir-ritonavir reduces the viral clearance time and length of hospital stay in hospitalized patients with COVID-19. Nirmatrelvir-ritonavir might be a promising drug to reduce the virus load and the heavy burden of healthcare systems.

COVID-19 as a Risk Factor for Alzheimer's Disease

Severe acute respiratory disease coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19) pandemic. Although a primarily respiratory disease, recent reports indicate that it also affects the central nervous system (CNS). Over 25% of COVID-19 patients report neurological symptoms such as memory loss, anosmia, hyposmia, confusion, and headaches. The neurological outcomes may be a result of viral entry into the CNS and/or resulting neuroinflammation, both of which underlie an elevated risk for Alzheimer's disease (AD). Herein, we ask: Is COVID-19 a risk factor for AD? To answer, we identify the literature and review mechanisms by which COVID-19-mediated neuroinflammation can contribute to the development of AD, evaluate the effects of acute versus chronic phases of infection, and lastly, discuss potential therapeutics to address the rising rates of COVID-19 neurological sequelae.

COVID-19 rebound after oral treatment in a nursing home facility: A case series

Paxlovid (nirmatrevir/ritonavir) is a 2 drug regimen taken together twice daily for 5 days was authorized for emergency use for nonhospitalized patients who are at risk for the progression of coronavirus disease (COVID-19). However, recurrence of symptoms 2-8 days after completing the treatment course has been recently recognized. In some cases patients tested negative on a direct SARS-CoV-2 viral test and then tested positive again (rebound COVID-19). The disease is mild and requires no additional antiviral treatment. Data are limited based on anecdotal case reports and few studies. According to the available data it is unclear if rebound symptoms are due to the drug treatment, drug resistance, re-infection or impaired immunity.

Viral proteases as therapeutic targets

Some medically important viruses-including retroviruses, flaviviruses, coronaviruses, and herpesviruses-code for a protease, which is indispensable for viral maturation and pathogenesis. Viral protease inhibitors have become an important class of antiviral drugs. Development of the first-in-class viral protease inhibitor saquinavir, which targets HIV protease, started a new era in the treatment of chronic viral diseases. Combining several drugs that target different steps of the viral life cycle enables use of lower doses of individual drugs (and thereby reduction of potential side effects, which frequently occur during long term therapy) and reduces drug-resistance development. Currently, several HIV and HCV protease inhibitors are routinely used in clinical practice. In addition, a drug including an inhibitor of SARS-CoV-2 main protease, nirmatrelvir (co-administered with a pharmacokinetic booster ritonavir as Paxlovid®), was recently authorized for emergency use. This review summarizes the basic features of the proteases of human immunodeficiency virus (HIV), hepatitis C virus (HCV), and SARS-CoV-2 and discusses the properties of their inhibitors in clinical use, as well as development of compounds in the pipeline.

Outcomes with and without outpatient SARS-CoV-2 treatment for patients with COVID-19 and systemic autoimmune rheumatic diseases: A retrospective cohort study

Objective

To investigate temporal trends, severe outcomes, and rebound among systemic autoimmune rheumatic disease (SARD) patients according to outpatient SARS-CoV-2 treatment.

Methods

We performed a retrospective cohort study investigating outpatient SARS-CoV-2 treatments among SARD patients at Mass General Brigham (23/Jan/2022-30/May/2022). We identified SARS-CoV-2 infection by positive PCR or antigen test (index date=first positive test) and SARDs using diagnosis codes and immunomodulator prescription. Outpatient treatments were confirmed by medical record review. The primary outcome was hospitalization or death within 30 days following the index date. COVID-19 rebound was defined as documentation of negative then newly-positive SARS-CoV-2 tests. The association of any vs. no outpatient treatment with hospitalization/death was assessed using multivariable logistic regression.

Results

We analyzed 704 SARD patients with COVID-19 (mean age 58.4 years, 76% female, 49% with rheumatoid arthritis). Treatment as outpatient increased over calendar time (p<0.001). A total of 426(61%) received outpatient treatment: 307(44%) with nirmatrelvir/ritonavir, 105(15%) with monoclonal antibodies, 5(0.7%) with molnupiravir, 3(0.4%) with outpatient remdesivir, and 6(0.9%) with combinations. There were 9/426 (2.1%) hospitalizations/deaths among those treated as outpatient compared to 49/278 (17.6%) among those with no outpatient treatment (adjusted odds ratio [aOR] 0.12, 0.05 to 0.25). 25/318 (8%) of patients who received oral outpatient treatment had documented COVID-19 rebound.

Conclusion

Outpatient treatment was strongly associated with lower odds of severe COVID-19 compared to no outpatient treatment. At least 8% of SARD patients experienced COVID-19 rebound. These findings highlight the importance of outpatient COVID-19 treatment for SARD patients and the need for further research on rebound.

KEY MESSAGES

What is already known on this topic?

Previous studies suggest that monoclonal antibodies are an effective outpatient treatment option for patients at high-risk of severe COVID-19, including those with systemic autoimmune rheumatic diseases (SARDs).Nirmatrelvir/ritonavir and molnupiravir are recently-authorized effective oral outpatient SARS-CoV-2 treatment options, but clinical trials were performed among the general population, mostly among unvaccinated and prior to Omicron viral variants.Oral outpatient SARS-CoV-2 treatments may result in COVID-19 rebound, characterized by newly-positive COVID-19 testing and recurrent symptoms, but no studies have investigated rebound prevalence among SARD patients.

What this study adds?

This is one of the first studies investigating outpatient SARS-CoV-2 treatments among SARD patients that includes oral options and quantifies the prevalence of COVID-19 rebound.Outpatient treatment was associated with 88% reduced odds of severe COVID-19 compared to no treatment.At least 8% of SARDs receiving oral outpatient treatment experienced COVID-19 rebound.

How this study might affect research practice or policy?

These results should encourage clinicians to prescribe and SARD patients to seek prompt outpatient COVID-19 treatment.This research provides an early estimate of the prevalence of COVID-19 rebound after oral outpatient treatment to quantify this risk to clinicians and SARD patients and encourage future research.

Pharmacokinetics of Nirmatrelvir and Ritonavir in COVID-19 Patients with End-Stage Renal Disease on Intermittent Hemodialysis

Nirmatrelvir/ritonavir is an effective antiviral therapy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Use is not recommended in patients with end-stage renal disease (ESDR) due to a lack of data. We investigated the pharmacokinetics of nirmatrelvir/ritonavir (150 mg/100 mg twice a day) in four patients with ESRD undergoing hemodialysis. Nirmatrelvir peak concentrations ranged from 4,563 to 7,898 ng/mL and declined after hemodialysis. Concentrations were up to 4-fold higher but still within the range known from patients without ESRD, without accumulation of nirmatrelvir after the end of treatment.