Nirmatrelvir-Ritonavir and COVID-19 Mortality and Hospitalization Among Patients With Vulnerability to COVID-19 Complications

Pooled analysis of the MANTICO2 and MONET randomized controlled trials comparing drug efficacy for early treatment of COVID-19 during Omicron waves

BACKGROUND

The clinical effectiveness of early therapies for mild-to-moderate COVID-19, comparing antivirals and monoclonal antibodies (mAbs) during the Omicron era, has not been conclusively assessed through a post-approval comparative trial. We present a pooled analysis of two randomized clinical trials conducted during Omicron waves.

METHODS

The MANTICO2/MONET trial is a pooled analysis of two multicentric, independent, phase-4, three-arm, superiority, randomized, open-label trials. Nonhospitalized patients with early mild-to-moderate COVID-19 (≤5 days after symptoms' onset) and at least one risk factor for disease progression were randomized 1:1:1 to receive 500 mg of intravenous sotrovimab (SOT) or 600 mg of intramuscular tixagevimab/cilgavimab (TGM/CGM) or oral 5-days course of nirmatrelvir/ritonavir (NMV/r) 300/100 mg BID. Primary outcome was COVID-19-related hospitalization or death within 29 days after randomization. Fisher's exact test for pooled data and incidence of failure was reported as overall and by arm with respective 95% CI. Pairwise comparisons across the arms were conducted using unadjusted exact logistic regression. An analysis by means of a doubly robust marginal model using augmented inverse probability weighting (AIPW) was also conducted to estimate the potential outcomes (Pom) in each treatment group and their difference by the average treatment effect (ATE). Analysis of symptom persistence within 30 days after randomization was performed using a 2-level hierarchical mixed-effects logistic model with a random intercept at the patient's level. Point estimates and 95% confidence intervals were adjusted for age and sex and calculated using ANOVA-like methods for the mixed effects logistic model. These trials are registered with the European Clinical Trials Database, EudraCT2021-002612-31 (MANTICO2) and EudraCT2021-004188-28 (MONET) and ClinicalTrials.gov, NCT05321394 (MANTICO2).

FINDINGS

Between March 2022 and February 2023, 991 patients (SOT = 332, TGM/CGM = 327, NMV/r = 332) were enrolled in 15 Italian centers. The overall mean age was 66 years; 482 participants (48.80%) were male, and 856 were vaccinated with at least a primary course (86%). Among the 8/991 hospitalizations observed, one resulted in death. The overall estimate of failure was 0.81% (95%CI; 0.35-1.58%). The odds ratio (OR) for the primary outcome in the NMV/r arm compared to the TGM/CGM and SOT arms was 8.41 (95% CI 1.21 to infinity; p = 0.015) and 2.42 (95% CI 0.19 to infinity; p = 0.499), respectively. No significant difference was observed between SOT and TGM/CGM (OR 0.32; 95% CI 0.032-1.83; p = 0.174). Results were similar when we applied the marginal weighted model accounting for potential residual confounding bias. There was no evidence for a difference in the prevalence of symptoms between treatment groups, except for cough, which was higher in the SOT group compared to the other two groups at the 21-day follow-up (P = 0.039) and a higher prevalence of nausea at the 7-day follow-up in the NMV/r group compared to the mAbs group (p = 0.036).

INTERPRETATION

NMV/r was superior to TGM/CGM in reducing hospital admission or death in clinically vulnerable patients with SARS-CoV-2 infection treated within 5 days of symptoms' onset. No significant difference in symptom prevalence over time across the arms was found.

How Immunocompromised Hosts Were Left Behind in the Quest to Control the COVID-19 Pandemic

The immunocompromised population was disproportionately affected by the severe acute respiratory syndrome coronavirus 2 pandemic. However, these individuals were largely excluded from clinical trials of vaccines, monoclonal antibodies, and small molecule antivirals. Although the community of scientists, clinical researchers, and funding agencies have proven that these therapeutics can be made and tested in record time, extending this progress to vulnerable and medically complex individuals from the start has been a missed opportunity. Here, we advocate that it is paramount to plan for future pandemics by investing in specific clinical trial infrastructure for the immunocompromised population to be prepared when the need arises.

Outcomes and Healthcare Resource Utilization in Patients with COVID-19 Treated with Nirmatrelvir-Ritonavir: Real-World Data Analysis

Background: Nirmatrelvir-ritonavir was granted emergency use authorization in Israel in January 2022 to treat high-risk patients with mild-to-moderate COVID-19. The aim of the study was to assess the association between nirmatrelvir-ritonavir treatment and COVID-19-related hospitalization and healthcare resource utilization (HCRU) in a country with a high level of vaccinations compared to patients who were offered treatment and declined. Methods: The Maccabi Healthcare Services dataset was used to identify high-risk SARS-CoV-2-positive adults from January to February 2022 who received nirmatrelvir-ritonavir within 5 days of symptom onset (treatment group) or who were offered nirmatrelvir-ritonavir treatment and declined it (reference group). COVID-19-related hospitalizations and all-cause mortality and HCRU within 30 days were compared between treatment and reference groups using inverse probability of treatment weighting. Results: Treatment and reference groups included 3460 (median age, 68.4 years) and 1654 (70.2 years) patients, respectively. Patients with ≥1 dose of COVID-19 vaccine accounted for 89.5% (treatment group) and 72.1% (reference group) of the total. Treatment was associated with a lower risk of COVID-19-related hospitalization (adjusted OR, 0.59 [95% CI, 0.41,0.83]). Results were similar by age group (18-64/≥65 years) and among patients with/without vaccination in the prior 180 days. There were 11 (0.3%) versus 11 (0.7%) deaths in the treatment and reference groups, respectively. Treated patients had lower inpatient HCRU and greater less intensive outpatient HCRU (e.g., telemedicine and emergency room visits). Conclusions: Nirmatrelvir-ritonavir treatment was associated with a reduced risk of COVID-19-related hospitalization and a shift to less intensive outpatient HCRU. Comparison with a reference group of nirmatrelvir-ritonavir-eligible patients who declined treatment enabled an unbiased outcome assessment. Real-world data gathered during the Omicron BA.1 variant wave of COVID-19 in Israel support the continued use of nirmatrelvir-ritonavir for high-risk adults of all ages, regardless of previous vaccinations.

Real-world effectiveness of early anti-SARS therapy in severely immunocompromised COVID-19 outpatients during the SARS-CoV-2 omicron variant era: a propensity score-adjusted retrospective cohort study

BACKGROUND

The effectiveness of the early treatment for antiviral agents in SARS-CoV-2 infection is closely related to patient comorbidities. Data on effectiveness in immunocompromised patients are limited, with reports involving highly heterogeneous and not well-defined populations. We aimed to assess the effectiveness of treatment in reducing hospitalizations in a real-world cohort of severely immunocompromised COVID-19 outpatients.

PATIENTS AND METHODS

We conducted a multicentre, retrospective, observational cohort study of immunocompromised outpatients attended in infectious diseases departments from 1 January to 31 December 2022. Propensity score matching (PSM) multivariable logistic regression models were used to estimate the adjusted odds ratio [(aOR, 95% confidence interval (CI)] for the association between antiviral prescription and outcome (COVID-19-related hospitalization up to Day 90).

RESULTS

We identified 746 immunocompromised outpatients with confirmed SARS-CoV-2 infection. After eligibility criteria and PSM, a total of 410 patients were analysed: 205 receiving treatment (remdesivir, sotrovimab or nirmatrelvir/ritonavir) and 205 matched controls. Fifty-two patients required at least one COVID-19-related hospitalization 8 (3.9%) versus 44 (21.5%) in the antiviral and matched control cohorts, respectively. There were 13 deaths at 90 days, of which only 4 were COVID-19-related and none in the antiviral treatment group. After adjustment for residual confounders, the use of early therapy was associated with a protective effect on the risk of hospitalization [aOR 0.13 (0.05-0.29)], as was the use of biological immunomodulators [aOR 0.27 (0.10-0.74)], whereas chronic obstructive pulmonary disease [aOR 4.65 (1.09-19.69)] and anti-CD20 use [aOR 2.76 (1.31-5.81)] increased the odds.

CONCLUSIONS

Early antiviral treatment was associated with a reduced risk of COVID-19-related hospitalization in ambulatory severely immunocompromised COVID-19 patients.

The winding road: Infectious disease considerations for CAR-T and other novel adoptive cellular therapies in the era of COVID-19

Adoptive cellular therapies (ACT) are novel, promising treatments for life-threatening malignancies. In addition to the better known chimeric antigen receptor (CAR) T cells, ACTs include tumor infiltrating lymphocytes (TIL), cancer antigen-specific T cell receptors (TCRs), and CAR-NK (natural killer) cells. In key historic milestones, several adoptive therapies recently received FDA approvals, including 6 CAR-T products for the treatment of hematologic malignancies and the first TIL therapy for the treatment for metastatic melanoma. The rapid pace of clinical trials in the field and the discoveries they provide are ushering in a new era of cancer immunotherapy. However, the potential complications of these therapies are still not fully understood. In particular, patients receiving ACT may be at increased risk for severe infections due to immunocompromise resulting from their underlying malignancies, which are further compounded by the immune derangements that develop in the setting of cellular immunotherapy and/or the preconditioning treatment needed to enhance ACT efficacy. Moreover, these treatments are being readily implemented at a time following the height of the COVID-19 pandemic, and it remains unclear what additional risks these patients may face from SARS-CoV-2 and similar infections. Here, we examine the evidence for infectious complications with emerging adoptive therapies, and provide a focused review of the epidemiology, complications, and clinical management for COVID-19 in CAR-T recipients to understand the risk this disease may pose to recipients of other forms of ACT.

Identifying Veterans Who Benefit From Nirmatrelvir-Ritonavir: A Target Trial Emulation

BACKGROUND

Nirmatrelvir-ritonavir is recommended for persons at risk for severe coronavirus disease 2019 (COVID-19) but remains underutilized. Information on which eligible groups are likely to benefit from treatment is needed.

METHODS

We conducted a target trial emulation study in the Veterans Health Administration comparing nirmatrelvir-ritonavir treated versus matched untreated veterans at risk for severe COVID-19 who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from April 2022 through March 2023. We measured incidence of any hospitalization or all-cause mortality at 30 days. Outcomes were measured for the entire cohort, as well as among subgroups defined by 30-day risk of death or hospitalization, estimated using an ensemble risk prediction model.

RESULTS

Participants were 87% male with median age 66 years and 16% unvaccinated. Compared with matched untreated participants, those treated with nirmatrelvir-ritonavir (n = 24 205) had a lower 30-day risk for hospitalization (1.80% vs 2.30%; risk difference [RD], -0.50% points [95% confidence interval {CI}: -.69 to -.35]) and death (0.11% vs 0.30%; RD, -0.20 [95% CI: -.24 to -.13]). The greatest reductions in combined hospitalization or death were observed in the highest risk quartile (RD -2.85 [95% CI: -3.94 to -1.76]), immunocompromised persons (RD -1.91 [95% CI: -3.09 to -.74]), and persons aged ≥75 years (RD -1.16 [95% CI: -1.73 to -.59]). No reductions were observed in the 2 lowest risk quartiles or persons younger than 65 years.

CONCLUSIONS

Nirmatrelvir-ritonavir was effective in reducing 30-day hospitalization and death in older veterans, those at highest predicted risk for severe outcomes, and immunocompromised groups. Benefit was not observed in younger veterans or groups at lower predicted risk for hospitalization and death.

Structural basis for the inhibition of the HCoV-NL63 main protease Mpro by X77

Human coronaviruses are a group of pathogens that primarily cause respiratory and intestinal diseases. Infection can easily cause respiratory symptoms, as well as a variety of serious complications. There are several types of human coronaviruses, such as SARS-CoV, MERS-CoV, HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, and SARS-CoV-2. The prevalence of COVID-19 has led to a growing focus on drug research against human coronaviruses. The main protease (Mpro) from human coronaviruses is a relatively conserved that controls viral replication. X77 was discovered to have extremely high inhibitory activity against SARS-CoV-2 Mpro through the use of computer-simulated docking. In this paper, we have resolved the crystal structure of the HCoV-NL63 Mpro complexed with X77 and analyzed their interaction in detail. This data provides essential information for solving their binding modes and their structural determinants. Then, we compared the binding modes of X77 with SARS-CoV-2 Mpro and HCoV-NL63 Mpro in detail. This study illustrates the structural basis of HCoV-NL63 Mpro binding to the inhibitor X77. The structural insights derived from this study will inform the development of new drugs with broad-spectrum resistance to human coronaviruses.

Effectiveness of nirmatrelvir/ritonavir and molnupiravir in non-hospitalized adults with COVID-19: systematic review and meta-analysis of observational studies

OBJECTIVE

To determine the effectiveness of nirmatrelvir/ritonavir and molnupiravir among vaccinated and unvaccinated non-hospitalized adults with COVID-19.

METHODS

Observational studies of nirmatrelvir/ritonavir or molnupiravir compared to no antiviral drug treatment for COVID-19 in non-hospitalized adults with data on vaccination status were included. We searched MEDLINE, EMBASE, Scopus, Web of Science, WHO COVID-19 Research Database and medRxiv for reports published between 1 January 2022 and 8 November 2023. The primary outcome was a composite of hospitalization or mortality up to 35 days after COVID-19 diagnosis. Risk of bias was assessed with ROBINS-I. Risk ratios (RR), hazard ratios (HR) and risk differences (RD) were separately estimated using random-effects models.

RESULTS

We included 30 cohort studies on adults treated with nirmatrelvir/ritonavir (n = 462 279) and molnupiravir (n = 48 008). Nirmatrelvir/ritonavir probably reduced the composite outcome (RR 0.62, 95%CI 0.55-0.70; I2 = 0%; moderate certainty) with no evidence of effect modification by vaccination status (RR Psubgroup = 0.47). In five studies, RD estimates against the composite outcome for nirmatrelvir/ritonavir were 1.21% (95%CI 0.57% to 1.84%) in vaccinated and 1.72% (95%CI 0.59% to 2.85%) in unvaccinated subgroups.Molnupiravir may slightly reduce the composite outcome (RR 0.75, 95%CI 0.67-0.85; I2 = 32%; low certainty). Evidence of effect modification by vaccination status was inconsistent among studies reporting different effect measures (RR Psubgroup = 0.78; HR Psubgroup = 0.08). In two studies, RD against the composite outcome for molnupiravir were -0.01% (95%CI -1.13% to 1.10%) in vaccinated and 1.73% (95%CI -2.08% to 5.53%) in unvaccinated subgroups.

CONCLUSIONS

Among cohort studies of non-hospitalized adults with COVID-19, nirmatrelvir/ritonavir is effective against the composite outcome of severe COVID-19 independent of vaccination status. Further research and a reassessment of molnupiravir use among vaccinated adults are warranted.

REGISTRATION

PROSPERO CRD42023429232.

Oral antivirals for COVID-19 among patients with cancer

PURPOSE

Immunocompromised individuals, such as those diagnosed with cancer, are at a significantly higher risk for severe illness and mortality when infected with SARS-CoV-2 (COVID-19) than the general population. Two oral antiviral treatments are approved for COVID-19: Paxlovid® (nirmatrelvir/ritonavir) and Lagevrio® (molnupiravir). There is a paucity of data regarding the benefit from these antivirals among immunocompromised patients with cancer, and recent studies have questioned their efficacy among vaccinated patients, even those with risk factors for severe COVID-19.

METHODS

We evaluated the efficacy and safety of nirmatrelvir/ritonavir and molnupiravir in preventing severe illness and death using our database of 457 patients with cancer and COVID-19 from Brown University-affiliated hospitals.

RESULTS

Sixty-seven patients received nirmatrelvir/ritonavir or molnupiravir and were compared to 45 concurrent controls who received no antiviral treatment despite being eligible to receive it. Administration of nirmatrelvir/ritonavir or molnupiravir was associated with improved survival and lower 90-day all-cause and COVID-19-attributed mortality (p < 0.05) and with lower peak O2 requirements (ordinal odds ratio [OR] 1.52, 95% confidence interval [CI] 0.92-2.56).

CONCLUSION

Acknowledging the small size of our sample as a limitation, we concluded that early antiviral treatment might be beneficial to immunocompromised individuals, particularly those with cancer, when infected with SARS-CoV-2. Larger-scale, well-stratified studies are needed in this patient population.

SARS-CoV-2 evolution has increased resistance to monoclonal antibodies and first-generation COVID-19 vaccines: Is there a future therapeutic role for soluble ACE2 receptors for COVID-19?

COVID-19 has caused calamitous health, economic and societal consequences. Although several COVID-19 vaccines have received full authorization for use, global deployment has faced political, financial and logistical challenges. The efficacy of first-generation COVID-19 vaccines is waning and breakthrough infections are allowing ongoing transmission and evolution of SARS-CoV-2. Furthermore, COVID-19 vaccine efficacy relies on a functional immune system. Despite receiving three primary doses and three or more heterologous boosters, some immunocompromised patients may not be adequately protected by COVID-19 vaccines and remain vulnerable to severe disease. The evolution of new SARS-CoV-2 variants has also resulted in the rapid obsolescence of monoclonal antibodies. Convalescent plasma from COVID-19 survivors has produced inconsistent results. New drugs such as Paxlovid (nirmatrelvir/ritonavir) are beyond the reach of low- and middle-income countries. With widespread use of Paxlovid, it is likely nirmatrelvir-resistant clades of SARS-CoV-2 will emerge in the future. There is thus an urgent need for new effective anti-SARS-CoV-2 treatments. The in vitro efficacy of soluble ACE2 against multiple SARS-CoV-2 variants including omicron (B.1.1.529), was recently described using a competitive ELISA assay as a surrogate marker for virus neutralization. This indicates soluble wild-type ACE2 receptors are likely to be resistant to viral evolution. Nasal and inhaled treatment with soluble ACE2 receptors has abrogated severe disease in animal models of COVID-19. There is an urgent need for clinical trials of this new class of antiviral therapeutics, which could complement vaccines and Paxlovid.

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.

Oral antivirals for COVID-19 among patients with cancer

Purpose

Immunocompromised individuals, such as those diagnosed with cancer, are at a significantly higher risk for severe illness and mortality when infected with SARS-CoV-2 (COVID-19) than the general population. Two oral antiviral treatments are approved for COVID-19: Paxlovid® (nirmatrelvir/ritonavir) and Lagevrio® (molnupiravir). There is a paucity of data regarding the benefit from these antivirals among immunocompromised patients with cancer, and recent studies have questioned their efficacy among vaccinated patients, even those with risk factors for severe COVID-19.

Methods

We evaluated the efficacy and safety of nirmatrelvir/ritonavir and molnupiravir in preventing severe illness and death using our database of 457 patients with cancer and COVID-19 from Brown University-affiliated hospitals. 67 patients received nirmatrelvir/ritonavir or molnupiravir and were compared to 56 concurrent controls who received no antiviral treatment despite being eligible to receive it.

Results

Administration of nirmatrelvir/ritonavir or molnupiravir was associated with improved survival and lower 90-day all-cause and COVID-19-attributed mortality (p<0.05) and with lower peak O2 requirements (ordinal odds ratio [OR] 1.52, 95% confidence interval [CI] 0.92-2.56).

Conclusion

Acknowledging the small size of our sample as a limitation, we concluded that early antiviral treatment might be beneficial to immunocompromised individuals, particularly those with cancer, when infected with SARS-CoV-2. Larger-scale, well-stratified studies are needed in this patient population.

Structural Basis for the Inhibition of SARS-CoV-2 Mpro D48N Mutant by Shikonin and PF-07321332

Preventing the spread of SARS-CoV-2 and its variants is crucial in the fight against COVID-19. Inhibition of the main protease (Mpro) of SARS-CoV-2 is the key to disrupting viral replication, making Mpro a promising target for therapy. PF-07321332 and shikonin have been identified as effective broad-spectrum inhibitors of SARS-CoV-2 Mpro. The crystal structures of SARS-CoV-2 Mpro bound to PF-07321332 and shikonin have been resolved in previous studies. However, the exact mechanism regarding how SARS-CoV-2 Mpro mutants impact their binding modes largely remains to be investigated. In this study, we expressed a SARS-CoV-2 Mpro mutant, carrying the D48N substitution, representing a class of mutations located near the active sites of Mpro. The crystal structures of Mpro D48N in complex with PF-07321332 and shikonin were solved. A detailed analysis of the interactions between Mpro D48N and two inhibitors provides key insights into the binding pattern and its structural determinants. Further, the binding patterns of the two inhibitors to Mpro D48N mutant and wild-type Mpro were compared in detail. This study illustrates the possible conformational changes when the Mpro D48N mutant is bound to inhibitors. Structural insights derived from this study will inform the development of new drugs against novel coronaviruses.