Efficacy of Licensed Monoclonal Antibodies and Antiviral Agents against the SARS-CoV-2 Omicron Sublineages BA.1 and BA.2

A phase I/II study of adoptive SARS-CoV-2-specific T cells in immunocompromised hosts with or at risk of severe COVID-19 infection

BACKGROUND

Post-transplant or hematological cancer patients have a higher risk of mortality after infection with ancestral and early variants of severe acute respiratory syndrome (SARS)-CoV-2. Adoptive cell therapy (ACT) with virus-specific T cells (VSTs) could augment endogenous T cell immunity to avoid disease deterioration before viral clearance.

METHODS

We established a third-party SARS-CoV-2-specific T cell (COVID-T) bank in 2020 (NCT04351659) using convalescent and/or vaccinated donors. In a phase I/II study (NCT04457726), 13 adult and pediatric patients, acutely positive for SARS-CoV-2 and predicted to have a high chance of mortality, were recruited from September 2021 to February 2022. Twelve patients received a single dose of COVID-T cells, matched on at least 1 HLA.

RESULTS

A dose of either 75,000 or 150,000 IFN-γ+CD3+ cells/m2 SARS-COV-2-specific T cells did not cause cytokine release syndrome, acute respiratory distress syndrome, or graft-versus-host disease. In the 8 patients who had detectable donor SARS-COV-2-specific T cells after ACT, none progressed to severe disease or died with COVID-19. In contrast, among the other four patients without evidence of donor micro-chimerism, two died of COVID-19.

CONCLUSIONS

Long-acting third-party VSTs from convalescent or vaccinated donors could be expediently produced and might be clinically useful in future pandemics, particularly before global vaccination is implemented.

Prevention and treatment strategies for kidney transplant recipients in the context of long-term existence of COVID-19

The sudden outbreak of coronavirus disease 2019 (COVID-19) in early 2020 posed a massive threat to human life and caused an economic upheaval worldwide. Kidney transplant recipients (KTRs) became susceptible to infection during the COVID-19 pandemic owing to their use of immunosuppressants, resulting in increased hospitalization and mortality rates. Although the current epidemic situation is alleviated, the long-term existence of COVID-19 still seriously threatens the life and health of KTRs with low immunity. The Omicron variant, a highly infectious but less-pathogenic strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has raised concerns among transplant physicians regarding managing KTRs diagnosed with this variant. However, currently, there are no clear and unified guidelines for caring for KTRs infected with this variant. Therefore, we aimed to summarize the ongoing research on drugs that can treat Omicron variant infections in KTRs and explore the potential of adjusting immunotherapy strategies to enhance their responsiveness to vaccines. Herein, we discuss the situation of KTRs since the emergence of COVID-19 and focus on various prevention and treatment strategies for KTRs since the Omicron variant outbreak. We hope to assist physicians in managing KTRs in the presence of long-term COVID-19 variants.

Real world effectiveness of sotrovimab in preventing COVID-19-related hospitalisation or death in patients infected with Omicron BA.2

BACKGROUND

Laboratory-based evidence indicates that neutralization of the BA.2 (Omicron) variant by sotrovimab is reduced versus previous SARS-CoV-2 variants. Since there is a lack of real-world data, we investigated whether sotrovimab has reduced clinical efficacy against the BA.2 variant.

METHODS

We performed a prospective cohort study using real-world data from 1180 randomly-selected BA.2 variant-infected patients. Follow-up to study endpoints averaged 29 days. For mild cases (not requiring oxygen-supplementation), primary outcomes were requiring O2-supplementation, intensive care unit (ICU) admission or death. For moderate-to-severe COVID-19 cases (requiring oxygen-supplementation other than mechanical ventilation), the primary outcome was ICU admission or death.

RESULTS

Patients in the sotrovimab group (n = 569) and control patients (n = 611) were included. Sotrovimab-treated patients versus controls had reduced risk of death (0.4% vs 6.4%, p < 0.001), need for oxygen supplementation (3.5% vs 12.8%, p < 0.001) and ICU admission (0.2% vs 4.9%, p < 0.001). The adjusted-odds ratio for developing any of these outcomes was 0.090 (95% CI 0.049-0.165, p < 0.001). Subgroup analysis of moderate-to-severe sotrovimab-treated patients versus controls revealed reduced mortality (17.7% vs 37.2%, p = 0.006) and ICU admission (0.0% vs 37.2%, p < 0.001). Adjusted-hazards ratio for death or ICU admission was 0.256 (95% CI 0.111-0.593, p < 0.001).

CONCLUSION

Sotrovimab was effective in reducing COVID-19 progression risk in high-risk BA.2 variant-infected patients. This finding may alleviate concerns about its clinical efficacy.

Switching the three-component Biginelli-like reaction conditions for the regioselective synthesis of new 2-amino[1,2,4]triazolo[1,5-a]pyrimidines

Among the eight different triazolopyrimidine isomers existing in nature, 1,2,4-triazolo[1,5-a]pyrimidine (TZP) is one of the most studied and used isomers in medicinal chemistry. For some years, our group has been involved in developing regioselective one-pot procedures for the synthesis of 2-amino-7-aryl-5-methyl- and 2-amino-5-aryl-7-methyl-TZPs of interest in the preparation of antiviral agents. In this work, taking advantage of a Biginelli-like multicomponent reaction (MCR), we report the identification of finely tunable conditions to regioselectively synthesize C-6 ester-substituted amino-TZP analogues, both in dihydro and oxidized forms. Indeed, the use of mild acidic conditions is strongly directed toward the regioselective synthesis of 5-aryl-7-methyl C-6-substituted TZP analogues, while the use of neutral ionic liquids shifted the regioselectivity towards 7-aryl-5-methyl derivatives. In addition, the novel synthesized scaffolds were functionalized at the C-2 position and evaluated for their antiviral activity against RNA viruses (influenza virus, flaviviruses, and SARS-CoV-2). Compounds 25 and 26 emerged as promising anti-flavivirus agents, showing activity in the low micromolar range.

An Overview on Anti-COVID-19 Drug Achievements and Challenges Ahead

The appearance of several coronavirus pandemics/epidemics during the last two decades (SARS-CoV-1 in 2002, MERS-CoV in 2012, and SARS-CoV-2 in 2019) indicates that humanity will face increasing challenges from coronaviruses in the future. The emergence of new strains with similar transmission characteristics as SARS-CoV-2 and mortality rates similar to SARS-CoV-1 (∼10% mortality) or MERS-CoV (∼35% mortality) in the future is a terrifying possibility. Therefore, getting enough preparations to face such risks is an inevitable necessity. The present study aims to review the drug achievements and challenges in the fight against SARS-CoV-2 with a combined perspective derived from pharmacology, pharmacotherapy, and medicinal chemistry insights. Appreciating all the efforts made during the past few years, there is strong evidence that the desired results have not yet been achieved and research in this area should still be pursued seriously. By expressing some pessimistic possibilities and concluding that the drug discovery and pharmacotherapy of COVID-19 have not been successful so far, this short essay tries to draw the attention of responsible authorities to be more prepared against future coronavirus epidemics/pandemics.

A low-background, fluorescent assay to evaluate inhibitors of diverse viral proteases

Multiple coronaviruses (CoVs) can cause respiratory diseases in humans. While prophylactic vaccines designed to prevent infection are available for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), incomplete vaccine efficacy, vaccine hesitancy, and the threat of other pathogenic CoVs for which vaccines do not exist have highlighted the need for effective antiviral therapies. While antiviral compounds targeting the viral polymerase and protease are already in clinical use, their sensitivity to potential resistance mutations as well as their breadth against the full range of human and preemergent CoVs remain incompletely defined. To begin to fill that gap in knowledge, we report here the development of an improved, noninfectious, cell-based fluorescent assay with high sensitivity and low background that reports on the activity of viral proteases, which are key drug targets. We demonstrate that the assay is compatible with not only the SARS-CoV-2 Mpro protein but also orthologues from a range of human and nonhuman CoVs as well as clinically reported SARS-CoV-2 drug-resistant Mpro variants. We then use this assay to define the breadth of activity of two clinically used protease inhibitors, nirmatrelvir and ensitrelvir. Continued use of this assay will help define the strengths and limitations of current therapies and may also facilitate the development of next-generation protease inhibitors that are broadly active against both currently circulating and preemergent CoVs. IMPORTANCE Coronaviruses (CoVs) are important human pathogens with the ability to cause global pandemics. Working in concert with vaccines, antivirals specifically limit viral disease in people who are actively infected. Antiviral compounds that target CoV proteases are already in clinical use; their efficacy against variant proteases and preemergent zoonotic CoVs, however, remains incompletely defined. Here, we report an improved, noninfectious, and highly sensitive fluorescent method of defining the sensitivity of CoV proteases to small molecule inhibitors. We use this approach to assay the activity of current antiviral therapies against clinically reported SARS-CoV-2 protease mutants and a panel of highly diverse CoV proteases. Additionally, we show this system is adaptable to other structurally nonrelated viral proteases. In the future, this assay can be used to not only better define the strengths and limitations of current therapies but also help develop new, broadly acting inhibitors that more broadly target viral families.

Consistent Effects of Early Remdesivir on Symptoms and Disease Progression Across At-Risk Outpatient Subgroups: Treatment Effect Heterogeneity in PINETREE Study

INTRODUCTION

In the PINETREE study, early remdesivir treatment reduced risk of coronavirus disease 2019 (COVID-19)-related hospitalizations or all-cause death versus placebo by 87% by day 28 in high-risk, non-hospitalized patients. Here we report results of assessment of heterogeneity of treatment effect (HTE) of early outpatient remdesivir, focusing on time from symptom onset and number of baseline risk factors (RFs).

METHODS

PINETREE was a double-blind, placebo-controlled trial of non-hospitalized patients with COVID-19 who were randomized within 7 days of symptom onset and had ≥ 1 RF for disease progression (age ≥ 60 years, obesity [body mass index ≥ 30], or certain coexisting medical conditions). Patients received remdesivir intravenously (200 mg on day 1 and 100 mg on days 2 and 3) or placebo.

RESULTS

In this subgroup analysis, HTE of remdesivir by time from symptom onset at treatment initiation and number of baseline RFs was not detected. Treatment with remdesivir reduced COVID-19-related hospitalizations independent of stratification by time from symptom onset to randomization. Of patients enrolled ≤ 5 days from symptom onset, 1/201 (0.5%) receiving remdesivir and 9/194 (4.6%) receiving placebo were hospitalized (hazard ratio [HR] 0.10; 95% confidence interval [CI] 0.01-0.82). Of those enrolled at > 5 days from symptom onset, 1/78 (1.3%) receiving remdesivir and 6/89 (6.7%) receiving placebo were hospitalized (HR 0.19; 95% CI 0.02-1.61). Remdesivir was also effective in reducing COVID-19-related hospitalizations when stratified by number of baseline RFs for severe disease. Of patients with ≤ 2 RFs, 0/159 (0.0%) receiving remdesivir and 4/164 (2.4%) receiving placebo were hospitalized; of those with ≥ 3 RFs, 2/120 (1.7%) receiving remdesivir and 11/119 (9.2%) receiving placebo were hospitalized (HR 0.16; 95% CI 0.04-0.73).

CONCLUSIONS

In the outpatient setting, benefit of remdesivir initiated within 7 days of symptoms appeared to be consistent across patients with RFs. Therefore, it may be reasonable to broadly treat patients with remdesivir regardless of comorbidities.

TRIAL REGISTRATION

ClinicalTrials.gov number NCT04501952.

Outcomes of SARS-CoV-2 infection among lung transplant recipients: A single center retrospective study

BACKGROUND

Lung transplant recipients (LTRs) are at increased risk for coronavirus disease 2019 (COVID-19)-associated complications.

METHODS

We aimed to describe the outcomes of polymerase chain reaction-documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in LTRs followed at our institution from March 2020 to July 2022. The primary outcome investigated was hospitalization or death from COVID-19-related symptoms within 28 days from diagnosis.

RESULTS

Overall, 60 cases were included, of which 18 (30%) reached the primary outcome. Only one patient (2%) died. Anti-spike monoclonal antibodies (mAbs) were administered as early treatment in 36 patients (casirivimab/imdevimab = 2, sotrovimab = 31, and tixagevimab/cilgavimab = 3). Multivariate analysis revealed that age >60 years (p = .003; odds ratio [OR] 9.41; confidence interval [CI] 2.52-41.05) was associated with a higher risk for the primary outcome, while administration of mAbs as early treatment (p = .030; OR 0.23; CI 0.06-0.87) was associated with a lower risk. No effect of vaccination and SARS-CoV-2 variant was observed. Forced expiratory volume in 1 s and forced vital capacity values did not decrease among 37 patients who had spirometry performed 1 month after COVID-19.

CONCLUSIONS

We observed a relatively low morbidity and mortality of COVID-19 in LTR. mAb administration was associated with a better outcome.

Use of Monoclonal Antibodies in Immunocompromised Patients Hospitalized with Severe COVID-19: A Retrospective Multicenter Cohort

OBJECTIVE

We aim to describe the safety and efficacy of sotrovimab in severe cases of COVID-19 in immunocompromised hosts.

METHODS

We used a retrospective multicenter cohort including immunocompromised hospitalized patients with severe COVID-19 treated with sotrovimab between October 2021 and December 2021.

RESULTS

We included 32 patients. The main immunocompromising conditions were solid organ transplantation (46.9%) and hematological malignancy (37.5%). Seven patients (21.9%) had respiratory progression: 12.5% died and 9.4% required mechanical ventilation. Patients treated within the first 14 days of their symptoms had a lower progression rate: 12.0% vs. 57.1%, p = 0.029. No adverse event was attributed to sotrovimab.

CONCLUSIONS

Sotrovimab was safe and may be effective in its use for immunocompromised patients with severe COVID-19. More studies are needed to confirm these preliminary data.

The preclinical discovery and development of molnupiravir for the treatment of SARS-CoV-2 (COVID-19)

INTRODUCTION

Molnupiravir (MOV) is a broad-spectrum oral antiviral agent approved for the treatment of COVID-19. The results from in vitro and in vivo studies suggested MOV activity against many RNA viruses such as influenza virus and some alphaviruses agents of epidemic encephalitis. MOV is a prodrug metabolized into the ribonucleoside analog β-D-N⁴-hydroxycytidine. It is incorporated into the viral RNA chain causing mutations impairing coding activity of the virus, thereby inhibiting viral replication.

AREAS COVERED

This review analyzes the in vitro and in vivo studies that have highlighted the efficacy of MOV and the main pre-authorization randomized controlled trials evaluating its safety, tolerability, and pharmacokinetics, as well as its antiviral efficacy against SARS-COV-2 infection.

EXPERT OPINION

MOV is an antiviral agent with an excellent tolerability profile with few drug-drug interactions. Treatment of mild-to-moderate COVID-19 can benefit from MOV administration in the precocious phases of the disease, prior to the trigger of an aberrant immune response responsible for the parenchymal damage to pulmonary and extrapulmonary tissues. However, its suspected mutagenic effect can be a factor limiting its use at least in selected populations and studies on its teratogen effects should be planned before it is authorized for use in the pediatric population or in pregnant women.

Liver tests abnormalities with licensed antiviral drugs for COVID-19: a narrative review

INTRODUCTION

Liver involvement in COVID-19 is multifactorial, and the three potential mechanisms are direct hepatocyte viral damage, vascular or cellular damage during the cytokine storm of severe COVID-19 and drug-induced liver injury. To date, three antivirals are licensed for the treatment of COVID-19 by most guidelines: remdesivir, molnupiravir, and ritonavir-boosted nirmatrelvir.

AREAS COVERED

We performed a narrative review about the hepatic safety profile of the three antivirals licensed for COVID-19 treatment. We used data about hepatobiliary adverse events from English-language randomized clinical trials (RCTs).

EXPERT OPINION

Remdesivir was found to be potentially hepatotoxic, and liver biochemistry abnormalities were common (2-34%) but mild and reversible. Molnupiravir exhibits a favorable safety profile and the increase in aminotransferases was usually mild and reversible (up to 11% of patients in one study). Ritonavir-boosted nirmatrelvir is potentially hepatotoxic, but in the only phase 3 RCT there were no safety issues and aspartate aminotransferase/alanine aminotransferase levels increase did not exceed 2.4% of patients. All antivirals have a favorable safety profile, but they are not sufficiently studied in patients with underlying chronic kidney or liver disease. In this special populations, antivirals should be used with caution and careful monitoring during treatment should be pursued on a case-by-case basis.

Molnupiravir When Used Alone Seems to Be Safe and Effective as Outpatient COVID-19 Therapy for Hemodialyzed Patients and Kidney Transplant Recipients

Background: Molnupiravir demonstrated an in vitro antiviral activity against positive-sense RNA viruses, including SARS-CoV-2. The study aimed to present the results of outpatient molnupiravir use in kidney transplant recipients and hemodialysis patients during the first months of 2022 in Poland. Methods: The retrospective observational cohort study at one kidney transplant center included 36 patients diagnosed with COVID-19 with an automated nucleic acid amplification test on nasopharyngeal swab specimens. All patients received molnupiravir for home-based therapy at a dose of 800 mg every 12 h orally for 5 days. Both kidney transplant recipients (n = 16) and hemodialysis patients (n = 20) presented a lot of comorbidities with a Charlson comorbidity index of 4.1 and 5.1, respectively. Results: Patients presented with fever, cough, and weakness followed by muscle and joint pain. Five kidney transplant recipients experienced acute kidney injury with a rise in serum creatinine level from 0.4 to 1.9 mg/dL. No serious side effects of molnupiravir therapy or interactions with immunosuppressive medications were observed. Symptoms of COVID-19 improved rapidly or resolved within 24–48 h of starting treatment. Conclusion: The study suggests the safety and efficacy of molnupiravir therapy alone early after the onset of SARS-CoV-2 infection, but further investigations should be performed to confirm our preliminary results. To the best of the authors’ knowledge, it is the first published report on molnupiravir use in end-stage kidney disease (ESKD) patients on hemodialysis and the third concerning kidney transplant recipients.