A Double-Blind, Randomized, Placebo-Controlled, Phase II Clinical Study To Evaluate the Efficacy and Safety of Camostat Mesylate (DWJ1248) in Adult Patients with Mild to Moderate COVID-19

Design, synthesis and biological evaluation of biaryl amide derivatives against SARS-CoV-2 with dual-target mechanism

The COVID-19 pandemic highlights the urgent need to develop effective small-molecule antivirals. Thirty-three novel biaryl amide derivatives were synthesized and evaluated for anti-coronaviral activity. Some significant SARs were uncovered and the intensive structure modifications led to the most active compounds 8b and 8h. The broad-spectrum anti-coronaviral effects of 8h were validated at RNA and protein levels. 8h inhibits coronavirus replication at multiple stages, from virus entry to virus dsRNA synthesis. The mechanism of action showed that 8h may simultaneously act on 3CLpro and TMPRSS2 to display anti-coronaviral effects. 8h combined with RdRp inhibitor showed synergistic inhibitory activity against coronavirus. This study confirmed that biaryl amide derivatives may be a new class of potential therapeutic agents against coronavirus with multiple target effect, worthy of further investigation.

An Update on SARS-CoV-2 Clinical Trial Results-What We Can Learn for the Next Pandemic

The coronavirus disease 2019 (COVID-19) pandemic has claimed over 7 million lives worldwide, providing a stark reminder of the importance of pandemic preparedness. Due to the lack of approved antiviral drugs effective against coronaviruses at the start of the pandemic, the world largely relied on repurposed efforts. Here, we summarise results from randomised controlled trials to date, as well as selected in vitro data of directly acting antivirals, host-targeting antivirals, and immunomodulatory drugs. Overall, repurposing efforts evaluating directly acting antivirals targeting other viral families were largely unsuccessful, whereas several immunomodulatory drugs led to clinical improvement in hospitalised patients with severe disease. In addition, accelerated drug discovery efforts during the pandemic progressed to multiple novel directly acting antivirals with clinical efficacy, including small molecule inhibitors and monoclonal antibodies. We argue that large-scale investment is required to prepare for future pandemics; both to develop an arsenal of broad-spectrum antivirals beyond coronaviruses and build worldwide clinical trial networks that can be rapidly utilised.

Host Receptor Targeting to Treat Covid-19

Not long after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the cause of coronavirus disease 2019 (Covid-19), in vitro experiments revealed that SARS-CoV-2 infection of human cells depended on the binding of the viral spike protein to the human cell-surface receptor angiotensin-converting enzyme 2 (ACE-2).1 Additional experiments demonstrated that infection could be blocked by inhibiting transmembrane protease, serine 2 (TMPRSS2), which is a host enzyme that cleaves the viral spike protein after binding to ACE-2 and facilitates entry of the virus into the host cell.

Respiratory virus infections after allogeneic stem cell transplantation: Current understanding, knowledge gaps, and recent advances

Before the COVID-19 pandemic, common community-acquired seasonal respiratory viruses (CARVs) were a significant threat to the health and well-being of allogeneic hematopoietic cell transplant (allo-HCT) recipients, often resulting in severe illness and even death. The pandemic has further highlighted the significant risk that immunosuppressed patients, including allo-HCT recipients, face when infected with SARS-CoV-2. As preventive transmission measures are relaxed and CARVs circulate again among the community, including in allo-HSCT recipients, it is crucial to understand the current state of knowledge, gaps, and recent advances regarding CARV infection in allo-HCT recipients. Urgent research is needed to identify seasonal respiratory viruses as potential drivers for future pandemics.

One Week of Oral Camostat Versus Placebo in Nonhospitalized Adults With Mild-to-Moderate Coronavirus Disease 2019: A Randomized Controlled Phase 2 Trial

BACKGROUND

Camostat inhibits severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in vitro. We studied the safety and efficacy of camostat in ACTIV-2/A5401, a phase 2/3 platform trial of therapeutics for COVID-19 in nonhospitalized adults.

METHODS

We conducted a phase 2 study in adults with mild-to-moderate COVID-19 randomized to oral camostat for 7 days or a pooled placebo arm. Primary outcomes were time to improvement in COVID-19 symptoms through day 28, proportion of participants with SARS-CoV-2 RNA below the lower limit of quantification (LLoQ) from nasopharyngeal swabs through day 14, and grade ≥3 treatment-emergent adverse events (TEAEs) through day 28.

RESULTS

Of 216 participants (109 randomized to camostat, 107 to placebo) who initiated study intervention, 45% reported ≤5 days of symptoms at study entry and 26% met the protocol definition of higher risk of progression to severe COVID-19. Median age was 37 years. Median time to symptom improvement was 9 days in both arms (P = .99). There were no significant differences in the proportion of participants with SARS-CoV-2 RNA

CONCLUSIONS

In a phase 2 study of nonhospitalized adults with mild-to-moderate COVID-19, oral camostat did not accelerate viral clearance or time to symptom improvement, or reduce hospitalizations or deaths. Clinical Trials Registration. ClinicalTrials.gov identifier: NCT04518410.

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Key Words

• COVID-19
• SARS-CoV-2
• camostat
• outpatient
• phase 2

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MESH Headings

• Humans
• Adult
• COVID-19
• SARS-CoV-2
• RNA, Viral
• Time Factors
• Treatment Outcome

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Grants

• UM1 AI069423 NIAID NIH HHS
• UM1 AI069424 NIAID NIH HHS
• UM1 AI069432 NIAID NIH HHS
• UL1 TR000124 NCATS NIH HHS
• UM1 AI068634 NIAID NIH HHS
• UM1 AI069481 NIAID NIH HHS
• U01 AI068636 NIAID NIH HHS
• UL1 TR001881 NCATS NIH HHS
• UM1 AI068636 NIAID NIH HHS
• UM1AI068636 NIH HHS
• UM1 AI106701 NIAID NIH HHS
• K08 AI155173 NIAID NIH HHS
• P30 AI060354 NIAID NIH HHS
• National Institute of Allergy and Infectious Diseases
• National Institutes of Health

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Affiliation(s)

Nikolaus Jilg Department of Medicine, Massachusetts General Hospital and Department of Medicine, Brigham Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
Kara W Chew Department of Medicine, University of California, Los Angeles, California, USA
Mark J Giganti Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
Eric S Daar Department of Medicine, University of California Los Angeles Center, Torrance, California, USA
David A Wohl Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
Arzhang Cyrus Javan Division of AIDS, National Institutes of Health, Rockville, Maryland, USA
Amy Kantor Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
Carlee Moser Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
Robert W Coombs Department of Medicine, University of Washington, Seattle, Washington, USA
Gene Neytman Quantum Clinical Trials, Miami Beach, Florida, USA
Keila Hoover Miami Clinical Research, Miami, Florida, USA
Atasi Jana Sagent Pharmaceuticals, Schaumburg, Illinois, USA
Phil A Hart Department of Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
Alexander L Greninger Department of Medicine, University of Washington, Seattle, Washington, USA
Bob Szurgot Sagent Pharmaceuticals, Schaumburg, Illinois, USA
Joseph J Eron Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
Judith S Currier Department of Medicine, University of Los Angeles, Los Angeles, California, USA
Michael D Hughes Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
Davey M Smith Department of Medicine, University of California, San Diego, San Diego, California, USA
Jonathan Z Li Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

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Safety Evaluation and Population Pharmacokinetics of Camostat Mesylate and Its Major Metabolites Using a Phase I Study

Camostat mesylate is expected to be promising as a treatment option for COVID-19, in addition to other indications for which it is currently used. Furthermore, in vitro experiments have confirmed the potential of camostat and its metabolites to be effective against COVID-19. Therefore, clinical trials were conducted to evaluate the safety and pharmacokinetic characteristics of camostat after single-dose administration. Additionally, we aim to predict the pharmacokinetics of repeated dosing through modeling and simulation based on clinical trials. Clinical trials were conducted on healthy Korean adults, and an analysis was carried out of the metabolites of camostat, GBPA, and GBA. Pharmacokinetic modeling and simulation were performed using Monolix. There were no safety issues (AEs, physical examinations, clinical laboratory tests, vital sign measurements, and ECG) during the clinical trial. The pharmacokinetic characteristics at various doses were identified. It was confirmed that AUC last and Cmax increased in proportion to dose in both GBPA and GBA, and linearity was also confirmed in log-transformed power model regression. Additionally, the accumulation index was predicted (1.12 and 1.08 for GBPA and GBA). The pharmacokinetics of camostat for various dose administrations and indications can be predicted prior to clinical trials using the developed camostat model. Furthermore, it can be used for various indications by connecting it with pharmacodynamic information.

SARS-CoV-2 Omicron entry is type II transmembrane serine protease-mediated in human airway and intestinal organoid models

SARS-CoV-2 can enter cells after its spike protein is cleaved by either type II transmembrane serine proteases (TTSPs), like TMPRSS2, or cathepsins. It is now widely accepted that the Omicron variant uses TMPRSS2 less efficiently and instead enters cells via cathepsins, but these findings have yet to be verified in more relevant cell models. Although we could confirm efficient cathepsin-mediated entry for Omicron in a monkey kidney cell line, experiments with protease inhibitors showed that Omicron (BA.1 and XBB1.5) did not use cathepsins for entry into human airway organoids and instead utilized TTSPs. Likewise, CRISPR-edited intestinal organoids showed that entry of Omicron BA.1 relied on the expression of the serine protease TMPRSS2 but not cathepsin L or B. Together, these data force us to rethink the concept that Omicron has adapted to cathepsin-mediated entry and indicate that TTSP inhibitors should not be dismissed as prophylactic or therapeutic antiviral strategy against SARS-CoV-2. IMPORTANCE Coronavirus entry relies on host proteases that activate the viral fusion protein, spike. These proteases determine the viral entry route, tropism, host range, and can be attractive drug targets. Whereas earlier studies using cell lines suggested that the Omicron variant of SARS-CoV-2 has changed its protease usage, from cell surface type II transmembrane serine proteases (TTSPs) to endosomal cathepsins, we report that this is not the case in human airway and intestinal organoid models, suggesting that host TTSP inhibition is still a viable prophylactic or therapeutic antiviral strategy against current SARS-CoV-2 variants and highlighting the importance of relevant human in vitro cell models.

Aprotinin-Drug against Respiratory Diseases

Aprotinin (APR) was discovered in 1930. APR is an effective pan-protease inhibitor, a typical "magic shotgun". Until 2007, APR was widely used as an antithrombotic and anti-inflammatory drug in cardiac and noncardiac surgeries for reduction of bleeding and thus limiting the need for blood transfusion. The ability of APR to inhibit proteolytic activation of some viruses leads to its use as an antiviral drug for the prevention and treatment of acute respiratory virus infections. However, due to incompetent interpretation of several clinical trials followed by incredible controversy in the literature, the usage of APR was nearly stopped for a decade worldwide. In 2015-2020, after re-analysis of these clinical trials' data the restrictions in APR usage were lifted worldwide. This review discusses antiviral mechanisms of APR action and summarizes current knowledge and prospective regarding the use of APR treatment for diseases caused by RNA-containing viruses, including influenza and SARS-CoV-2 viruses, or as a part of combination antiviral treatment.

Therapeutic developments for SARS-CoV-2 infection-Molecular mechanisms of action of antivirals and strategies for mitigating resistance in emerging variants in clinical practice

This article systematically presents the current clinically significant therapeutic developments for the treatment of COVID-19 by providing an in-depth review of molecular mechanisms of action for SARS-CoV-2 antivirals and critically analyzing the potential targets that may allow the selection of resistant viral variants. Two main categories of agents can display antiviral activity: direct-acting antivirals, which act by inhibiting viral enzymes, and host-directed antivirals, which target host cell factors that are involved in steps of the viral life cycle. We discuss both these types of antivirals, highlighting the agents that have already been approved for treatment of COVID-19, and providing an overview of the main molecules that are currently in drug development. Direct-acting antivirals target viral enzymes that are essential in the viral life cycle. Three direct-acting antivirals are currently in use: two are nucleoside analogs that inhibit the RNA-dependent RNA polymerase of SARS-CoV-2, i.e., remdesivir and molnupiravir, and the third one, nirmatrelvir/ritonavir, is an inhibitor of SARS-CoV-2 main protease. The potential for induction of viral resistance is discussed for each of these antivirals, along with their clinical activity on each of the SARS-CoV-2 variants and sublineages that have been dominant over the course of the pandemic, i.e., Alpha, Delta, as well as Omicron and its sublineages BA.1, BA.2, BA.5, BQ.1 and XBB. Host-directed antivirals are currently in preclinical or clinical development; these agents target host cell enzymes that are involved in facilitating viral entry, replication, or virion release. By blocking these enzymes, viral replication can theoretically be effectively stopped. As no SARS-CoV-2 host-directed antiviral has been approved so far, further research is still needed and we present the host-directed antivirals that are currently in the pipeline. Another specific type of agents that have been used in the treatment of COVID-19 are neutralizing antibodies (NAbs). Their main binding site is the spike protein, and therefore their neutralization activity is influenced by mutations occurring in this region. We discuss the main changes in neutralization activity of NAbs for the most important dominant SARS-CoV-2 variants. Close monitoring of emerging variants and sublineages is still warranted, to better understand the impact of viral mutations on the clinical efficiency of antivirals and neutralizing antibodies developed for the treatment of COVID-19.