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1.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315433

ABSTRACT

Background: Drug repurposing is an attractive strategy to rapidly develop affordable therapy against COVID-19. The antifungal drug itraconazole exerts in vitro activity against SARS-CoV-2 comparable to that of hydroxychloroquine. Preclinical and clinical studies are required to investigate if itraconazole is effective for the treatment and/or prevention of COVID-19. Methods: Due to the initial absence of preclinical models the effect of itraconazole was explored in a clinical, proof-of-concept, open-label, single-center study, in which hospitalized patients with COVID-19 were randomly assigned to receive standard of care with or without itraconazole. The primary outcome was the cumulative score of the clinical status until day 15 based on the 7-point ordinal scale of the World Health Organization. Other outcomes included time to sustained clinical improvement, duration of supplemental oxygen and evolution of nasopharyngeal viral load. In parallel, itraconazole was evaluated in a newly established hamster model of acute SARS-CoV-2 infection and transmission, as soon as the model was validated. Findings: In the hamster acute infection model, itraconazole did not reduce viral load in lungs, stools or ileum, despite adequate plasma and lung drug concentrations. In the transmission model, itraconazole failed to prevent viral transmission. The clinical trial was prematurely discontinued after evaluation of the preclinical studies and interim analysis that showed no trends for a more favorable outcome with itraconazole: mean cumulative score of the clinical status 49 vs 47, ratio of geometric means 1.01 (95% CI 0.85 to 1.19), median time to clinical improvement 10 vs 9 days, hazard ratio 0.94 (95% CI 0.56 to 1.60) for itraconazole vs standard of care. Interpretation: Despite in vitro activity, itraconazole was not effective in a preclinical COVID-19 hamster model. A proof-of-concept clinical study was ended prematurely because of futility. Trial Registration: (EudraCT 2020-001243-15)Funding: Covid-19-Fund KU Leuven, Research Foundation - Flanders (FWO), Horizon 2020, Bill and Melinda Gates FoundationDeclaration of Interests: Initial dug screening and discovery of the antiviral effect of itraconazole was done in collaboration with Johnson & Johnson and described in a separate manuscript. Scientists from Johnson & Johnson also performed drug measurements on hamster samples and provided guidance on the dosing regimens for the preclinical studies. The company had no role in the design, execution, analysis, publication or funding of the clinical trial.Author Conflict of Interests: None to declare.Ethics Approval Statement: The institutional Ethical Committee approved all animal experiments (license P065-2020).The study was conducted in accordance with the International Conference on Harmonization Guidelines for Good Clinical Practice and the Declaration of Helsinki. The protocol was approved by the institutional Ethics Committee and by the Belgian Federal Agency for Medicines and Health Products (EudraCT 2020-001243-15). The trial was part of the DAWn clinical studies.

2.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-295926

ABSTRACT

We have identified camelid single-domain antibodies (VHHs) that cross-neutralize SARS-CoV-1 and −2, such as VHH72, which binds to a unique highly conserved epitope in the viral receptor-binding domain (RBD) that is difficult to access for human antibodies. Here, we establish a protein engineering path for how a stable, long-acting drug candidate can be generated out of such a VHH building block. When fused to human IgG1-Fc, the prototype VHH72 molecule prophylactically protects hamsters from SARS-CoV-2. In addition, we demonstrate that both systemic and intranasal application protects hACE-2-transgenic mice from SARS-CoV-2 induced lethal disease progression. To boost potency of the lead, we used structure-guided molecular modeling combined with rapid yeast-based Fc-fusion prototyping, resulting in the affinity-matured VHH72_S56A-Fc, with subnanomolar SARS-CoV-1 and −2 neutralizing potency. Upon humanization, VHH72_S56A was fused to a human IgG1 Fc with optimized manufacturing homogeneity and silenced effector functions for enhanced safety, and its stability as well as lack of off-target binding was extensively characterized. Therapeutic systemic administration of a low dose of VHH72_S56A-Fc antibodies strongly restricted replication of both original and D614G mutant variants of SARS-CoV-2 virus in hamsters, and minimized the development of lung damage. This work led to the selection of XVR011 for clinical development, a highly stable anti-COVID-19 biologic with excellent manufacturability. Additionally, we show that XVR011 is unaffected in its neutralizing capacity of currently rapidly spreading SARS-CoV-2 variants, and demonstrate its unique, wide scope of binding across the Sarbecovirus clades.

3.
Sci Transl Med ; 13(621): eabi7826, 2021 Nov 24.
Article in English | MEDLINE | ID: covidwho-1450584

ABSTRACT

Broadly neutralizing antibodies are an important treatment for individuals with coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Antibody-based therapeutics are also essential for pandemic preparedness against future Sarbecovirus outbreaks. Camelid-derived single domain antibodies (VHHs) exhibit potent antimicrobial activity and are being developed as SARS-CoV-2­neutralizing antibody-like therapeutics. Here, we identified VHHs that neutralize both SARS-CoV-1 and SARS-CoV-2, including now circulating variants. We observed that the VHHs bound to a highly conserved epitope in the receptor binding domain of the viral spike protein that is difficult to access for human antibodies. Structure-guided molecular modeling, combined with rapid yeast-based prototyping, resulted in an affinity enhanced VHH-human immunoglobulin G1 Fc fusion molecule with subnanomolar neutralizing activity. This VHH-Fc fusion protein, produced in and purified from cultured Chinese hamster ovary cells, controlled SARS-CoV-2 replication in prophylactic and therapeutic settings in mice expressing human angiotensin converting enzyme 2 and in hamsters infected with SARS-CoV-2. These data led to affinity-enhanced selection of the VHH, XVR011, a stable anti­COVID-19 biologic that is now being evaluated in the clinic.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Animals , Antibodies, Neutralizing , Antibodies, Viral , Humans , Models, Animal , SARS-CoV-2
5.
Microorganisms ; 9(5)2021 Apr 27.
Article in English | MEDLINE | ID: covidwho-1244074

ABSTRACT

Favipiravir (T-705) is a broad-spectrum antiviral drug that inhibits RNA viruses after intracellular conversion into its active form, T-705 ribofuranosyl 5'-triphosphate. We previously showed that T-705 is able to significantly inhibit the replication of chikungunya virus (CHIKV), an arbovirus transmitted by Aedes mosquitoes, in mammalian cells and in mouse models. In contrast, the effect of T-705 on CHIKV infection and replication in the mosquito vector is unknown. Since the antiviral activity of T-705 has been shown to be cell line-dependent, we studied here its antiviral efficacy in Aedes-derived mosquito cells and in Aedes aegypti mosquitoes. Interestingly, T-705 was devoid of anti-CHIKV activity in mosquito cells, despite being effective against CHIKV in Vero cells. By investigating the metabolic activation profile, we showed that, unlike Vero cells, mosquito cells were not able to convert T-705 into its active form. To explore whether alternative metabolization pathways might exist in vivo, Aedes aegypti mosquitoes were infected with CHIKV and administered T-705 via an artificial blood meal. Virus titrations of whole mosquitoes showed that T-705 was not able to reduce CHIKV infection in mosquitoes. Combined, these in vitro and in vivo data indicate that T-705 lacks antiviral activity in mosquitoes due to inadequate metabolic activation in this animal species.

6.
EBioMedicine ; 66: 103288, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1141720

ABSTRACT

BACKGROUND: The antifungal drug itraconazole exerts in vitro activity against SARS-CoV-2 in Vero and human Caco-2 cells. Preclinical and clinical studies are required to investigate if itraconazole is effective for the treatment and/or prevention of COVID-19. METHODS: Due to the initial absence of preclinical models, the effect of itraconazole was explored in a clinical, proof-of-concept, open-label, single-center study, in which hospitalized COVID-19 patients were randomly assigned to standard of care with or without itraconazole. Primary outcome was the cumulative score of the clinical status until day 15 based on the 7-point ordinal scale of the World Health Organization. In parallel, itraconazole was evaluated in a newly established hamster model of acute SARS-CoV-2 infection and transmission, as soon as the model was validated. FINDINGS: In the hamster acute infection model, itraconazole did not reduce viral load in lungs, stools or ileum, despite adequate plasma and lung drug concentrations. In the transmission model, itraconazole failed to prevent viral transmission. The clinical trial was prematurely discontinued after evaluation of the preclinical studies and because an interim analysis showed no signal for a more favorable outcome with itraconazole: mean cumulative score of the clinical status 49 vs 47, ratio of geometric means 1.01 (95% CI 0.85 to 1.19) for itraconazole vs standard of care. INTERPRETATION: Despite in vitro activity, itraconazole was not effective in a preclinical COVID-19 hamster model. This prompted the premature termination of the proof-of-concept clinical study. FUNDING: KU Leuven, Research Foundation - Flanders (FWO), Horizon 2020, Bill and Melinda Gates Foundation.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/drug therapy , Itraconazole/pharmacology , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/pharmacokinetics , Antiviral Agents/therapeutic use , COVID-19/etiology , COVID-19/transmission , Chlorocebus aethiops , Disease Models, Animal , Drug Evaluation, Preclinical , Female , Humans , Itraconazole/administration & dosage , Itraconazole/pharmacokinetics , Itraconazole/therapeutic use , Male , Mesocricetus , Middle Aged , Pneumonia, Viral/drug therapy , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , Proof of Concept Study , SARS-CoV-2/drug effects , Treatment Outcome , Vero Cells
7.
Nat Commun ; 11(1): 5838, 2020 11 17.
Article in English | MEDLINE | ID: covidwho-933686

ABSTRACT

Emergence of SARS-CoV-2 causing COVID-19 has resulted in hundreds of thousands of deaths. In search for key targets of effective therapeutics, robust animal models mimicking COVID-19 in humans are urgently needed. Here, we show that Syrian hamsters, in contrast to mice, are highly permissive to SARS-CoV-2 and develop bronchopneumonia and strong inflammatory responses in the lungs with neutrophil infiltration and edema, further confirmed as consolidations visualized by micro-CT alike in clinical practice. Moreover, we identify an exuberant innate immune response as key player in pathogenesis, in which STAT2 signaling plays a dual role, driving severe lung injury on the one hand, yet restricting systemic virus dissemination on the other. Our results reveal the importance of STAT2-dependent interferon responses in the pathogenesis and virus control during SARS-CoV-2 infection and may help rationalizing new strategies for the treatment of COVID-19 patients.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/pathology , Coronavirus Infections/virology , Disease Models, Animal , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , STAT2 Transcription Factor/metabolism , Signal Transduction , Animals , Betacoronavirus/pathogenicity , COVID-19 , Coronavirus Infections/immunology , Coronavirus Infections/metabolism , Cricetinae , Immunity, Innate , Interferon Type I/genetics , Interferon Type I/metabolism , Lung/pathology , Lung/virology , Mice , Pandemics , Pneumonia, Viral/immunology , Pneumonia, Viral/metabolism , SARS-CoV-2 , STAT2 Transcription Factor/genetics , Virus Replication
8.
Proc Natl Acad Sci U S A ; 117(43): 26955-26965, 2020 10 27.
Article in English | MEDLINE | ID: covidwho-841910

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread around the globe after its emergence in Wuhan in December 2019. With no specific therapeutic and prophylactic options available, the virus has infected millions of people of which more than half a million succumbed to the viral disease, COVID-19. The urgent need for an effective treatment together with a lack of small animal infection models has led to clinical trials using repurposed drugs without preclinical evidence of their in vivo efficacy. We established an infection model in Syrian hamsters to evaluate the efficacy of small molecules on both infection and transmission. Treatment of SARS-CoV-2-infected hamsters with a low dose of favipiravir or hydroxychloroquine with(out) azithromycin resulted in, respectively, a mild or no reduction in virus levels. However, high doses of favipiravir significantly reduced infectious virus titers in the lungs and markedly improved lung histopathology. Moreover, a high dose of favipiravir decreased virus transmission by direct contact, whereas hydroxychloroquine failed as prophylaxis. Pharmacokinetic modeling of hydroxychloroquine suggested that the total lung exposure to the drug did not cause the failure. Our data on hydroxychloroquine (together with previous reports in macaques and ferrets) thus provide no scientific basis for the use of this drug in COVID-19 patients. In contrast, the results with favipiravir demonstrate that an antiviral drug at nontoxic doses exhibits a marked protective effect against SARS-CoV-2 in a small animal model. Clinical studies are required to assess whether a similar antiviral effect is achievable in humans without toxic effects.


Subject(s)
Amides/therapeutic use , Antiviral Agents/therapeutic use , Betacoronavirus/drug effects , Hydroxychloroquine/therapeutic use , Pyrazines/therapeutic use , Amides/pharmacokinetics , Animals , COVID-19/drug therapy , Chlorocebus aethiops , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Cricetinae , Disease Models, Animal , Disease Transmission, Infectious/prevention & control , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Female , Hydroxychloroquine/pharmacokinetics , Lung/drug effects , Lung/pathology , Lung/virology , Pyrazines/pharmacokinetics , SARS-CoV-2 , Treatment Outcome , Vero Cells , Viral Load/drug effects
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