Topical TMPRSS2 inhibition prevents SARS-CoV-2 infection in differentiated human airway cultures.

BACKGROUND: There are limited effective prophylactic/early treatments for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Viral entry requires spike protein binding to the angiotensin-converting enzyme-2 receptor and cleavage by transmembrane serine protease 2 (TMPRSS2), a cell surface serine protease. Targeting of TMPRSS2 by either androgen blockade or direct inhibition is in clinical trials in early SARS-CoV-2 infection. METHODS: We used differentiated primary human airway epithelial cells at the air-liquid interface to test the impact of targeting TMPRSS2 on the prevention of SARS-CoV-2 infection. RESULTS: We first modelled the systemic delivery of compounds. Enzalutamide, an oral androgen receptor antagonist, had no impact on SARS-CoV-2 infection. By contrast, camostat mesylate, an orally available serine protease inhibitor, blocked SARS-CoV-2 entry. However, oral camostat is rapidly metabolised in the circulation, with poor airway bioavailability. We therefore modelled local airway administration by applying camostat to the apical surface of differentiated airway cultures. We demonstrated that a brief exposure to topical camostat effectively restricts SARS-CoV-2 infection. CONCLUSION: These experiments demonstrate a potential therapeutic role for topical camostat for pre- or post-exposure prophylaxis of SARS-CoV-2, which can now be evaluated in a clinical trial.

A phase I study of high dose camostat mesylate in healthy adults provides a rationale to repurpose the TMPRSS2 inhibitor for the treatment of COVID-19.

Camostat mesylate, an oral serine protease inhibitor, is used to treat chronic pancreatitis and reflux esophagitis. Recently, camostat mesylate and its active metabolite 4-(4-guanidinobenzoyloxy)phenylacetic acid (GBPA) were reported to inhibit the infection of cells by severe acute respiratory syndrome coronavirus 2 by inhibiting type II transmembrane serine protease. We conducted a phase I study to investigate high-dose camostat mesylate as a treatment for coronavirus disease 2019. Camostat mesylate was orally administered to healthy adults at 600 mg 4 times daily under either of the following conditions: fasted state, after a meal, 30 min before a meal, or 1 h before a meal, and the pharmacokinetics and safety profiles were evaluated. In addition, the time of plasma GBPA concentration exceeding the effective concentration was estimated as the time above half-maximal effective concentration (EC50 ) by using pharmacokinetic/pharmacodynamic modeling and simulation. Camostat mesylate was safe and tolerated at all dosages. Compared with the fasted state, the exposure of GBPA after a meal and 30 min before a meal was significantly lower; however, no significant difference was observed at 1 h before a meal. The time above EC50 was 11.5 h when camostat mesylate 600 mg was administered 4 times daily in the fasted state or 1 h before a meal. Based on the results of this phase I study, we are currently conducting a phase III study.

Peptide and peptide-based inhibitors of SARS-CoV-2 entry.

To date, no effective vaccines or therapies are available against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pandemic agent of the coronavirus disease 2019 (COVID-19). Due to their safety, efficacy and specificity, peptide inhibitors hold great promise for the treatment of newly emerging viral pathogens. Based on the known structures of viral proteins and their cellular targets, antiviral peptides can be rationally designed and optimized. The resulting peptides may be highly specific for their respective targets and particular viral pathogens or exert broad antiviral activity. Here, we summarize the current status of peptides inhibiting SARS-CoV-2 entry and outline the strategies used to design peptides targeting the ACE2 receptor or the viral spike protein and its activating proteases furin, transmembrane serine protease 2 (TMPRSS2), or cathepsin L. In addition, we present approaches used against related viruses such as SARS-CoV-1 that might be implemented for inhibition of SARS-CoV-2 infection.

Camostat mesylate against SARS-CoV-2 and COVID-19-Rationale, dosing and safety.

The coronavirus responsible for COVID-19, SARS-CoV-2, utilizes a viral membrane spike protein for host cell entry. For the virus to engage in host membrane fusion, SARS-CoV-2 utilizes the human transmembrane surface protease, TMPRSS2, to cleave and activate the spike protein. Camostat mesylate, an orally available well-known serine protease inhibitor, is a potent inhibitor of TMPRSS2 and has been hypothesized as a potential antiviral drug against COVID-19. In vitro human cell and animal studies have shown that camostat mesylate inhibits virus-cell membrane fusion and hence viral replication. In mice, camostat mesylate treatment during acute infection with influenza, also dependent on TMPRSS2, leads to a reduced viral load. The decreased viral load may be associated with an improved patient outcome. Because camostat mesylate is administered as an oral drug, it may be used in outpatients as well as inpatients at all disease stages of SARS-CoV-2 infection if it is shown to be an effective antiviral agent. Clinical trials are currently ongoing to test whether this well-known drug could be repurposed and utilized to combat the current pandemic. In the following, we will review current knowledge on camostat mesylate mode of action, potential benefits as an antiviral agent and ongoing clinical trials.

COVID-19: therapeutic approaches description and discussion.

COVID-19 emerged in December 2019 in China, and since then, has disrupted global public health and changed economic paradigms. In dealing with the new Coronavirus, SARS-CoV-2, the world has not faced such extreme global fragility since the "Spanish flu" pandemic in 1918. Researchers globally are dedicating efforts to the search for an effective treatment for COVID-19. Drugs already used in a clinical setting for other pathologies have been tested as a new therapeutic approach against SARS-CoV-2, setting off a frenzy over the preliminary data of different studies. This work aims to compile and discuss the data published thus far. Despite the potential effects of some antivirals and antiparasitic against COVID-19, clinical studies must confirm real effectiveness. However, non-pharmacological approaches have proven to be the most efficient strategy to date.