key: cord-345371-pjbviagq authors: Lisi, Lucia; Lacal, Pedro Miguel; Barbaccia, Maria Luisa; Graziani, Grazia title: Approaching Coronavirus Disease 2019: mechanisms of action of repurposed drugs with potential activity against SARS-CoV-2 date: 2020-07-23 journal: Biochem Pharmacol DOI: 10.1016/j.bcp.2020.114169 sha: doc_id: 345371 cord_uid: pjbviagq On March 11, 2020, the World Health Organization (WHO) declared the severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2) a global pandemic. As of July 2020, SARS-CoV-2 has infected more than 14 million people and provoked more than 590,000 deaths, worldwide. From the beginning, a variety of pharmacological treatments has been empirically used to cope with the life-threatening complications associated with Corona Virus Disease 2019 (COVID-19). Thus far, only a couple of them and not consistently across reports have been shown to further decrease mortality, respect to what can be achieved with supportive care. In most cases, and due to the urgency imposed by the number and severity of the patients’ clinical conditions, the choice of treatment has been limited to repurposed drugs, approved for other indications, or investigational agents used for other viral infections often rendered available on a compassionate-use basis. The rationale for drug selection was mainly, though not exclusively, based either i) on the activity against other coronaviruses or RNA viruses in order to potentially hamper viral entry and replication in the epithelial cells of the airways, and/or ii) on the ability to modulate the excessive inflammatory reaction deriving from dysregulated host immune responses against the SARS-CoV-2. In several months, an exceptionally large number of clinical trials have been designed to evaluate the safety and efficacy of anti-COVID-19 therapies in different clinical settings (treatment or pre- and post-exposure prophylaxis) and levels of disease severity, but only few of them have been completed so far. This review focuses on the molecular mechanisms of action that have provided the scientific rationale for the empirical use and evaluation in clinical trials of structurally different and often functionally unrelated drugs during the SARS-CoV-2 pandemic. On January 30, 2020, the World Health Organization (WHO) declared the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; initially named 2019 novel coronavirus or 2019-nCoV) a public health emergency of international concern, highlighting the need for a coordinated international intervention to limit virus spreading. Few weeks later, on March 11, 2020, because of the rapid diffusion of the infection, the WHO announced that SARS-CoV-2 infection was a global pandemic. The first cases of respiratory disease caused by 2019-CoV-2, thereafter officially named COVID-19 (Corona Virus Disease 2019), likely occurred from a zoonotic transmission in China in December 2019 and since then infection has spread across 213 countries and territories. As of July, 2020, SARS-CoV-2 has infected more than 14,000,000 people and caused more than 590,000 deaths (https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situation-reports/ accessed July 19, 2020). Coronaviridae define a family of hundreds of enveloped, positive-sense, single-stranded RNA viruses that are known to cause diseases in animals. Sometimes these viruses become able to overcome the species barriers (spillover event) and, so far, 7 coronaviruses are known to cause human diseases. Among these, four human coronaviruses (i.e., HCov-229E, HCov-NL63, HCov-OC43 and HKU1) typically affect the upper respiratory tract and cause relatively minor symptoms. However, the other three coronaviruses [severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and SARS-CoV-2] are able to replicate in the lower respiratory tract and are responsible for severe forms of pneumonia that can be fatal (1). Phylogenetic analysis indicates that SARS-CoV-2 has high similarity (88-89%) with two coronaviruses circulating in Rhinolophus (horseshoe bats) (2) , but it is less closely related to the SARS-CoV (~79% similarity) and MERS-CoV (~50% similarity). Based on the sequence analysis of the 29.8 kb viral genome and on the presence of bats and live animals in the seafood wholesale market in Wuhan (Hubei province, China), where SARS-CoV-2 was detected for the first time, this virus might have arisen from bats or materials contaminated by bat droppings in the Chinese seafood market areas and transmitted to humans either directly or through an intermediate host (3) . Similar to the other respiratory coronaviruses, SARS-CoV-2 is transmitted primarily via the respiratory route in the form of droplets, with a possible, though yet unproven, fecal-oral transmission route (4, 5) . The virus is stable for several hours to days in aerosols and on various types of surfaces, suggesting that transmission may occur by person-to-person droplets as well as by contact with fomites in the proximity of infected patients (6) . Although many individuals remain asymptomatic, 97.5% of diseased patients display clinical symptoms within 11.5 days (7) . Patients with COVID-19 may exhibit mild to moderate symptoms, most commonly fever, fatigue, dry cough, anosmia/dysgeusia, or severe pneumonia with dyspnea, tachypnea, and hypoxemia. Actually, dyspnea is predictive of severe COVID-19 and intensive care unit (ICU) admission (8) . Other symptoms less frequently reported include muscle and joint pain, headache, diarrhea, nausea or vomiting, hemoptysis (9) . Severe COVID-19 is associated to acute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) that generally occur 8-9 days after symptom onset. As with SARS-CoV infection, an aggressive inflammatory reaction is responsible for the damage to the lung, indicating that the disease severity also depends on dysregulation of the host immune responses. Respiratory failure is the most common cause of death (>70%) of fatal COVID-19 cases. Furthermore, the massive release of cytokines by the immune system can result in cytokine storm and septic shock and/or multiple organs dysfunction syndromes in 28% of fatal cases (10, 11) . Other causes of death are cardiac failure, coagulopathy and renal failure (11) . SARS-CoV-2 appears also to target the central nervous system with anosmia and dysgeusia as early symptoms and convulsions that may develop later on (12) . Currently, the standard of care in patients showing ARDS includes oxygen therapy together with the administration of parenteral fluids. Furthermore, many patients with severe respiratory distress, hypoxemia and ARDS require invasive mechanical ventilation, and, if the situation deteriorates, extracorporeal membrane oxygenation support (13) . Therapeutic interventions including administration of drugs may vary from country to country and it is extremely difficult to harmonize the different protocols due also to the different disease stages of the patients (asymptomatic, pre-symptomatic, mild, severe, under mechanical ventilation). So far, there is not a standardized effective pharmacological treatment for COVID-19, a part from anecdotal evidence of efficacy. The scarce knowledge of the SARS-CoV-2 biology and of the host-pathogen interactions leading to COVID-19 has markedly hampered the prompt identification of suitable targets for the development of new therapies. A large number of exploratory clinical trials and pivotal studies are being carried out worldwide. Among them, the international "Solidarity trial" launched by the WHO on March 2020 with the aim to find an effective treatment for COVID-19 patients by comparing four different treatments (i.e., lopinavir/ritonavir, lopinavir/ritonavir plus interferon-β, chloroquine/hydroxychloroquine or remdesivir) against standard of care (see also sections 2 and 3). Presently, regulatory authorities all over the world underline the need of common and rigorous approaches to clinical trials in order to generate more robust evidence on the safety/efficacy of the different anti-SARS-CoV-2 treatments or vaccines that are being tested. Here, we review the recently published literature on the pharmacological treatments used so far and/or undergoing evaluation in clinical trials, with focus on the biochemical mechanisms of action of repurposed or investigational drugs, classified as agents directly targeting the virus ( Figure 1 and Table 1 ) and those used to treat the respiratory distress and inflammation associated with the cytokine release syndrome ( Figure 2 and Table 2 ). In addition, we summarize the main clinical trials completed or still ongoing in SARS-CoV-2 infected patients. The first step in any viral infection entails binding of the virus to a host cell through its target receptor. Both SARS-CoV and SARS-CoV-2 entry into cells requires the interaction of the viral spike (S) glycoprotein (the envelope-associated protein conferring coronaviruses the characteristic crown-like morphology) with the angiotensin-converting enzyme 2 (ACE2) (14) (15) (16) . ACE2 is a dimeric ectoenzyme with dipeptidyl carboxypeptidase activity. Although the ACE2 mRNA has been detected in a variety of tissues (17) , the protein has not always been analyzed or detected. The ACE2 protein is expressed at high levels on the surface of the lung alveolar epithelial cells and enterocytes of the small intestine providing an easily accessible route for SARS-CoV-2 infection (18) . The ACE2 protein is also present in smooth muscle, pericytes and endothelial cells of the vasculature, heart, kidney and this might account for the multi-organ dysfunction observed in severe COVID-19 patients (18) (19) (20) (21) (22) (23) . Other tissue sites where the ACE2 protein was detected include, among others, the basal epithelium of the nasal, nasopharynx oral mucosa, the basal cell layer of epidermis, and testis (18, 24) . The viral S glycoprotein is a trimer and each monomer contains two subunits, S1 and S2, of which S1 is responsible for the virus attachment to the host cell surface though the receptorbinding domain (RBD), whereas S2 is required for the fusion of the viral and cellular membranes. After the attachment step, the entry process requires the S protein priming by cellular proteases, consisting in the proteolytic cleavage at the S1-S2 boundary and at a downstream position in S2; this process leads to the exposure of a peptide that is involved in membrane fusion (25, 26) . The S proteins of Coronaviruses can be cleaved by various cellular proteases; in the case of SARS-CoV-2, the transmembrane protease serine 2 protease (TMPRSS2) plays a critical role in S protein priming, whilst the endosomal cysteine protease cathepsin L may replace TMPRSS2 in this function in cells other than those of the lung (27,28). Moreover, it has been recently demonstrated that the host cell protease furin can cleave the SARS-CoV-2 S protein at the S1/S2 site cleavage, an essential step for viral entry into lung cells (29). Since ACE2 is located within lipid rafts, cell infection by SARS-CoV-2 also requires interaction of the viral S protein with different raft components, including sialicacid-containing gangliosides; this interaction also facilitates the contact of the S protein with the ACE2 receptor (30). After cleavage of the S protein, SARS-CoV-2 can be induced to fuse at both the plasma membrane and the endosomal membrane (27,31). Various endocytic pathways have been described as being used for cell infection by different Coronaviruses, including clathrin-coated vesicles, caveolae as well as clathrin-and caveolae-independent mechanisms (32,33). Different antiviral agents or other drugs used for indications unrelated to virus infections have been used to block SARS-CoV-2 entry into the host cells either by i) inhibiting virus attachment and proteolytic cleavage of the S protein, ii) targeting key cellular enzymatic activities or proteins involved in the endocytic processes or iii) using a combination of both mechanisms ( Figure 1 ). Umifenovir (Arbidol) is a small indole-derivative molecule with a broad spectrum of activity against DNA/RNA and enveloped/non-enveloped viruses that prevents viral entry into the host cell (attachment and internalization), behaving as host-targeting and direct-acting antiviral agent (34,35). In particular, due to its hydrophobicity, umifenovir displays high affinity for the lipids of the host cell membranes altering their fluidity and rendering them less prone to fusion with the virus. This agent is also able to interact with aromatic residues of the viral glycoproteins involved in the attachment and in the membrane destabilization necessary for the fusion process. Furthermore, umifenovir markedly affects clathrin-mediated endocytosis by hampering the release of clathrin-coated pits from the plasma membrane with consequent slowing of vesicle intracellular trafficking and accumulation of clathrin-coated structures where the viral particles remain trapped (35). Finally, based on structural similarities between the umifenovir binding sites in the hemagglutinin of the H3N2 influenza virus and the S glycoprotein of SARS-CoV-2, it has been suggested that this drug might block the trimerization of the S glycoprotein, which is essential for the virus cell adherence and entry (36). Umifenovir is licensed (only in Russia and China) for the prophylaxis and treatment of influenza A and B infections but it has shown in vitro activity against infections by hepatitis C and B (HCV and HBV), Ebola and other viruses (37). In a clinical pilot trial conducted in sixty-nine COVID-19 patients, oral treatment with umifenovir (n=36) showed a tendency to reduce viral load and mortality rate as compared to the control group receiving interferon or other non-specified antiviral agents (0% vs 16%) (38) . The results of a retrospective cohort study in patients with COVID-19, without invasive ventilation, who received umifenovir plus lopinavir/ritonavir (n=16) or lopinavir/ritonavir only (n=17), showed a potential benefit of the triple combination therapy to reduce viral load and delay disease progression. In fact, after 14 days of treatment, in the umifenovir-treated group nasopharyngeal specimens were negative for SARS-CoV-2 in 94% of patients (vs 53% of the control group) and the chest computed tomography (CT) scans were improved in 69% of cases (vs 29% of the control group) (39) . Subsequently, umifenovir was tested as monotherapy (n=34) and its activity compared to that of lopinavir/ritonavir (n=16). On day 14 after treatment, no viral load was detected in the umifenovir group, whereas the virus was still found in 44.1% of patients treated with lopinavir/ritonavir (40) . Conversely, in another study with non-ICU patients (n=45) umifenovir failed to improve the prognosis and virus clearance compared to the control group receiving symptomatic treatment, including the most appropriate supportive care (n=36) (41) . A similar conclusion was drawn by an observational cohort study on the real-world efficacy and safety of umifenovir used as single agent or in combination with lopinavir/ritonavir. There was no evidence that adding umifenovir to lopinavir/ritonavir could shorten the time to negative conversion of SARS-CoV-2 nucleic acid in pharyngeal swabs or improve the symptoms (42). However, a retrospective analysis of adverse drug reactions in 217 Chinese patients with COVID-19, by a hospital pharmacovigilance system, reported a lower incidence of adverse effects (that were mostly at the gastrointestinal and hepatic level) for umifenovir compared to lopinavir/ritonavir (18.1% vs 63.8%) (43) . A small retrospective cohort study has recently suggested the use of umifenovir for post-exposure prophylaxis, based on the significant reduction of infection risk observed in family members (n=66 in 27 families) and health care workers (n=124) who were exposed to patients with confirmed SARS-CoV-2 infection (44) . Further clinical studies are ongoing to evaluate the role of umifenovir in COVID-19 management, used as monotherapy [NCT04260594] or in combination with other antiviral agents [NCT04350684, NCT04273763]. In the randomized, double-blind, placebo-controlled clinical NCT04350684 trial, umifenovir is added to a therapeutic regimen including interferon-β1a, lopinavir/ritonavir and a single dose of hydroxychloroquine plus standard of care. Baricitinib is a potent and selective inhibitor of the Janus kinases 1/2 (JAK1/JAK2), currently used in the therapy of rheumatoid arthritis. Based on the results of a BenevolentAI's knowledge graph, the small-molecule kinase inhibitor baricitinib was predicted to alter virus entry by inhibiting AP2-associated kinase 1 (AAK1) and cyclin G-associated kinase (GAK), which are likely involved in SARS-CoV-2 endocytosis (45) . The BenevolentAI's knowledge graphical method uses machine learning to integrate the scientific information on the biological processes involved in viral infection with that on the mechanisms of action of available drugs in order to identify potential new pharmacological targets and therapeutic indications. Besides exerting potential direct antiviral effects, baricitinib might prevent the dysregulated production of pro-inflammatory cytokines typically observed in COVID-19 patients via the inactivation of interleukin-6 (IL6)-JAK-signal transducer and activator of transcription (STAT) pathway (this activity will be more deeply discussed in section 3, especially regarding the JAK inhibitor ruxolitinib). Some clinical trials, also including placebo-controlled studies, are evaluating the safety and efficacy of baricitinb, mostly as 2- week add-on therapy in patients with mild to moderate COVID-19. Results from a small study in 12 patients with moderate COVID-19 pneumonia, treated with baricitinib in combination with lopinavir/ritonavir [NCT04358614], indicated that a 2-week oral treatment with the JAK1/2 inhibitor was well tolerated. Moreover, although proper control groups were missing, the authors reported improved clinical and laboratory parameters (46) . A favorable clinical course was also reported in an 87-year-old woman, with a mild-to-moderate COVID-19, chronically treated with baricitinib for rheumatoid arthritis, who also received other pharmacological treatments to control viral infection (i.e., lopinavir/ritonavir, hydroxychloroquine) (47) . This patient was part of a familiar cluster of COVID-19, and the three other family members (husband, son and daughter) received the same antiviral therapy with the exception of baricitinib. Interestingly, the patient's husband (90- Chloroquine and hydroxychloroquine are among the most frequently used drugs for the treatment of COVID-19 patients in view of their potential inhibitory activity on virus entry. However, other mechanisms appear to contribute to their antiviral activity, including impaired receptor recognition by coronaviruses due to altered terminal glycosylation of ACE2 (49) and inhibition of viral attachment to the lipid raft as a consequence of a reduced interaction of the SARS-CoV-2 S protein N-terminal domain with membrane gangliosides (30). Indeed, in vitro studies have demonstrated that chloroquine is able to block SARS-CoV-2 infection at lowmicromolar concentrations (50) (51) (52) . Furthermore, chloroquine and hydroxychloroquine exhibit immunomodulatory activity since they reduce the Toll-like receptor (TLR) signaling (that plays a crucial role in the innate immune system) and production of inflammatory cytokines, as well as the expression of co-stimulatory molecules in T cells (for a comprehensive review see 53) . So far, however, there is not conclusive or robust clinical evidence on the usefulness of quinolines in COVID-19. Starting from mid-February, 2020, chloroquine was included in the sixth version of the COVID-19 treatment guidelines by the National Health Commission of the People's Republic of China. According to these guidelines the initial recommended chloroquine dose was 500 mg twice daily for no more than 10 days; however, due to safety concerns the maximum therapy course was reduced to 7 days and a lower dose was recommended for patients weighing less than 50 kg. Based on clinical trials conducted in China in more than 10 hospitals, treatment of >100 patients with chloroquine is superior to control treatment in preventing pneumonia exacerbation, improving lung imaging results, accelerating virus-negative conversion, and shortening the disease course (54) . However, detailed information on the study design, patient characteristics or control treatment were not provided. The results of a blinded, randomized, controlled Chinese trial for COVID-19 pneumonia, reported a significant improvement in terms of symptoms and CT findings in patients treated with hydroxychloroquine (n=31; 400 mg/day for 5 days) compared to the control group (n=31) (55) . Conversely, in a previous pilot study in 30 treatment-naïve patients with confirmed COVID-19, hydroxychloroquine did not show any clinical benefit (56) . A French study on a cohort of 80 patients with severe COVID-19 treated with hydroxychloroquine (600 mg/day for 10 days plus the macrolide antibiotic azithromycin for 5 days) did not reveal antiviral activity or clinical benefit (57). A published interim analysis of a double-blind, randomized, phase IIB clinical trial [NCT0432352] performed in Brazil, after enrollment of the first 81 patients with severe ARDS treated with high and low chloroquine doses (i.e., 600 mg/twice/day for 10 days, n=41; 450 mg twice daily on day 1 and once daily for 4 days, n=40) indicated that the high-dosage group showed a higher incidence of cardiotoxic effects (QTc interval prolongation) and a higher mortality rate compared to the low-dosage group (39% vs 13%) (58). All these patients also received the macrolide antibiotic azithromycin that may induce cardiotoxic effects. These preliminary data indicate that high chloroquine dosage should not be recommended for treating critically ill COVID-19 patients. Although hydroxychloroquine is better tolerated than chloroquine, both agents may cause in the long-term life-threatening arrhythmias (an effect increased by the concomitant use of azithromycin), leucopenia, neuropsychiatric effects and retinopathy. In addition, quinoline overdose can lead to cardiovascular collapse, seizures and coma (59). Therefore, the use of chloroquine/hydroxychloroquine for COVID-19 management requires a careful patient selection and monitoring. Based on the initial publication in The Lancet of the results of a multinational registry analysis conducted by Surgisphere Corporation, showing that treatment with hydroxychloroquine/chloroquine (with or without a macrolide) in hospitalized COVID-19 patients (n=14,888) failed to induce clinical benefit and was associated with higher risk of death and cardiovascular complications compared to control treatment (n=81,144) (60), on May 23, 2020, the WHO temporarily halted the Solidarity Trial arm with chloroquine/hydroxychloroquine. Thereafter, the article was retracted by three of the four coauthors of the original article since Surgisphere (owned by one of the authors) did not make available to a third-party audit the complete dataset used for the study (61) . Thus, on June 3, 2020, the WHO announced that there was no reason to modify the Solidarity trial protocol and the arm with quinolines was resumed. Nevertheless, on the basis of a low benefit/risk ratio, the FDA retracted the Emergency Use Authorization (EUA) previously issued to hydroxychloroquine for use in COVID-19 hospitalized patients outside of clinical trials. To have a clear view on the overall risk-benefit ratio of using chloroquine/hydroxychloroquine especially in severely ill COVID-19 patients we will have to wait for the conclusion of welldesigned, multi-center, randomized, controlled studies. Actually, ClinicalTrials.gov lists a number of phase 3 studies testing chloroquine and more frequently hydroxychloroquine, alone six of them also received azithromycin (500 mg on the first day followed by 250 mg daily) to prevent bacterial infection. All patients treated with both drugs showed negative nasopharyngeal SARS-CoV-2 PCR conversion compared to 57.1% of those treated with hydroxychloroquine as single agent and 12.5% of the untreated ones (62) . The results of a French retrospective non-randomized study in a total of 1061 patients treated for at least 3 days with hydroxychloroquine plus azithromycin showed that early treatment with this drug combination was well-tolerated and associated with a very low fatality rate (0.9%) (63) . The mechanism underlying the potential azithromycin activity against SARS-CoV-2 still needs to be clarified; recently, it has been hypothesized that this antibiotic might inhibit CD147, a glycosylated transmembrane protein that would serve as additional receptor for SARS-CoV-2 cell invasion (64) . Furthermore, azithromycin might stimulate immune responses against the virus by inducing the synthesis of type I and III interferons, as demonstrated in epithelial cells collected from patients with chronic obstructive pulmonary disease (65) . As mentioned above, a number of clinical trials are currently evaluating azithromycin mostly in combination with hydroxychloroquine for the treatment of COVID-19 or as prophylaxis. Another approach to inhibit SARS-CoV-2 infection consists in inhibiting the protease that cleaves the S protein, thus facilitating viral entry and activation. TMPRSS2 is an androgen- (72, 73) . In addition, nafamostat is able to inhibit the coagulation and fibrinolytic systems, the kallikreinkinin system, the complement cascade, and activation of protease-activated receptors (74) . Therefore, their anti-inflammatory, anti-coagulant and fibrinolytic properties might contribute to attenuate the symptoms and complications occurring in COVID-19 patients. Both agents are approved in Japan for the treatment of pancreatitis, and nafamostat is also used for disseminated intravascular coagulation and as anticoagulant in extracorporeal circulation. Three case reports of elderly COVID-19 patients with pneumonia, all taking antivirals like lopinavir/ritonavir and hydroxychloroquine, showed that the introduction of nafamostat induced clinical and radiological improvement without significant adverse effects (75) Inhibition of the viral spike protein cleavage by cathepsin L in the late endosome might also result in decreased SARS-CoV-2 entry into the cells (80) . Once SARS-CoV-2 reaches the endosomes, the cysteinyl proteinase cathepsin L is the main protease that cleaves the S1 Once inside the cell, SARS-CoV-2, like other coronaviruses, uses two third of its positivesense single-stranded RNA genome as template to directly translate two open reading frames (ORF1a and ORF1ab), connected by a ribosomal frameshift site, into the two overlapping polyproteins, pp1a and pp1ab, which are afterward cleaved by viral proteases into 16 nonstructural proteins (nsps) (85) . Some nsps (including RNA-dependent RNA polymerase, helicase and other enzymatic activities required for the mRNA capping and proofreading) eventually contribute to form the replication-transcription complex, which is anchored to double-membrane vesicles integrated into a reticulovesicular network of modified endoplasmic reticulum membranes, also including convoluted membranes (86, 87) . The viral genomic RNA is encapsulated by the nucleocapsid N protein that thereafter buds into the ERGIC and acquires a membrane containing the S, E and M structural proteins. Finally, the virus is released by exocytosis ( Figure 1 ). The 3CL pro /M pro is highly conserved among various coronaviruses, and mutations in 3CL pro /M pro are often lethal to the virus (88, 89) . Therefore, 3CL pro /M pro is indispensable for viral replication and thus represents an attractive therapeutic target for inhibiting the coronavirus infection process (89) . This enzyme is a homodimeric cysteine protease whose recognition sequence at most sites of viral polyproteins is Leu-Gln↓(Ser,Ala,Gly). Several previous reports have indicated that the HIV aspartate protease inhibitors lopinavir and ritonavir have the potential to act also as SARS-CoV protease inhibitors through their binding to 3CL pro /M pro (90) (91) (92) (93) . For HIV treatment, the two drugs are used in combination, but ritonavir is administered at a dose that does not affect HIV protease activity but rather inhibits the cytochrome P450 3A4-mediated metabolism of lopinavir, thus increasing its plasma levels. Both drugs bind to amino acid residues present at the active site of SARS-CoV-2 Furthermore, based on a virtual docking prediction study, some HCV NS3/4A protease inhibitors (e.g., simeprevir, paritaprevir, grazoprevir, boceprevir, telaprevir) might also inhibit the 3CL pro /M pro (101, 102) . However, none of these agents is currently clinically evaluated for COVID-19 treatment. Concerning the other coronavirus protease PL pro , although considered another potential therapeutic target since it is crucial for viral replication, the development of SARS-CoV-2 PL pro inhibitors is still at an early stage (103), despite several investigational compounds have been found to efficiently inhibit the corresponding SARS-CoV and MERS-CoV enzyme (104). Another The adenosine analogue remdesivir is one the most frequently tested anti-SARS-CoV-2 agents and has been firstly approved in Japan for severe COVID-19. Remdesivir was originally developed for RNA virus infections and tested for Ebola during the 2018 outbreak in Democratic Republic of the Congo but failed to show clinical benefit. It has a broadspectrum antiviral activity, including MERS-CoV, SARS-CoV and SARS-CoV-2, both in vitro and in vivo in animal models (52, (106) (107) (108) (109) . Remdesivir is a prodrug that, after diffusion into the cells, is metabolized to the alanine metabolite GS-704277 and further converted into a nucleoside monophosphate, which is highly polar and remains trapped within the cell (106) . Host cell kinases eventually convert the monophosphate derivative into a triphosphate nucleotide that is misincorporated into the nascent RNA chain by the RNA dependent RNA polymerase with consequent inhibition of the RNA synthesis (110) . Remdesivir has been found to interact with the SARS-CoV-2 polymerase, competing with the physiological ATP nucleotide, and to behave as delayed-chain-terminator, since RNA synthesis is terminated after the addition of three nucleotides (105, 111, 112) . It should be noted that the efficacy of remdesivir or of other nucleoside/nucleotide-based agents, whose activity relies on their misincorporation into the viral genome, might be counteracted by a coronavirus proofreading exoribonuclease (nsp14) that would enable the virus to evade the pharmacological inhibition (113) . Intravenous remdesivir was used to treat the first COVID-19 patient diagnosed in the US with rapid improvement of the clinical conditions (114) and is regarded as one of the most promising agents for SARS-CoV-2. Presently, the drug is included in the National Institutes (117) . In an uncontrolled study where 61 patients (64% receiving mechanical ventilation) were treated with remdesivir on a compassionate-use basis, clinical improvement at 28 days was observed in 68% of patients (118) . However, this trial raised several criticisms on the study design and result interpretation, due to lack of control, small sample size, inappropriate data censoring, high variability of disease severity (119) (120) (121) (122) . In another study, remdesivir was administered as compassionate treatment to 32 hospitalized patients (18 of whom in ICU) and beneficial effects were observed on SARS-CoV-2 pneumonia, mainly in non-critically ill patients (123) . Remdesvir is usually well-tolerated for short courses. However, concerns were raised about its potential toxicity in patients with kidney dysfunction related not only to the drug-mediated injury of renal tubular epithelial cells, but also to the nephrotoxicity associated with the drug vehicle (i.e., sulfobutylether-β-cyclodextrin) required for the intravenous formulation (124) . Another nucleoside analogue used for COVID-19 is favipiravir, which acts as a competitive inhibitor of the RNA-dependent RNA polymerase. This agent was previously approved in Japan for the treatment of influenza A and B and, in particular, for novel or re-emerging influenza viruses (125) . Presently, the drug has been approved in Russia for COVID-19 and is investigated worldwide. Favipiravir, after undergoing intracellular tri-phosphorylation, exerts antiviral effects as a guanosine analogue, through several mechanisms including chain termination, slowed RNA synthesis and lethal mutagenesis (due to C-to-U and G-to-A transitions favored by the low cytosine content of SARS-CoV-2 genome) (126 High levels of IL6 and IL8 also contribute to hypercoagulation due to activation of the complement and coagulation cascades, causing disseminated intravascular coagulation (150, 151) . Waiting for an effective antiviral therapy or vaccine against the virus, any treatment that can decrease the severe symptoms of COVID-19 may help to attenuate the mortality rates and to improve the quality of life of severely ill patients. In this regard, several pharmacological therapies, with different mechanisms of action, have been used in order to improve the symptoms related to COVID-19. In the next section, we will consider the agents directed against the: a) cytokine storm and b) cardiovascular damage. The first category includes: i) anti-cytokine drugs, such as tocilizumab, sarilumab, siltuximab, olokizumab, ruxolitinib, baricitinib, anakinra, emapalumab, mavrilimumab; and ii) immunomodulating agents, such as interferon-β, interferon-α or interferon-λ, fingolimod, ozanimod, opaganib, CD24Fc, allogenic mesenchymal stem cells and the lately reappraised dexamethasone. The second group comprises: the anti-C5 complement monoclonal antibodies (mAbs) eculizumab and ravulizumab; anti-thrombotic and fibrinolytic agents; the phosphodiesterase type 5 inhibitor sildenafil; the vasoactive intestinal polypeptide analog aviptadil; and the anti VEGF-A mAb bevacizumab ( Figure 2) . However, the effects of the two drug sets are closely interconnected, as many drugs that have an impact on the circulatory system may also reduce circulating inflammatory cytokines. The first therapeutic agent used to counteract the inflammatory reaction in patients with (162) . Furthermore, a larger study on 100 patients with COVID-19 pneumonia accompanied by hyperinflammatory syndrome and acute respiratory failure described improvement or stabilization of the respiratory conditions in 77% of patients (163) . Case reports also supported the potential benefit from tocilizumab treatment (164) . A Chinese small retrospective study in 21 patients showed that tocilizumab is associated with rapid improvement of the clinical symptoms and hypoxemia, and prevention of clinical worsening in severe COVID-19 patients, without serious adverse events (165) . However, tocilizumab did not reduce ICU admission and mortality rates in 21 critically ill patients with severe COVID-19 pneumonia (166) . Tocilizumab treatment was found to be associated with an initial rise in IL6 levels, as an expected consequence of the mAb-mediated inhibition of IL6 interaction with its receptors, followed by a significant decrease of the c-reactive protein inflammatory marker (167). However, the D-dimer, measured as an indicator of intravascular fibrin formation, remained unaffected suggesting that tocilizumab might have limited effect on the activation of the coagulation cascade (163) . Furthermore, the clinical response to tocilizumab seems to be negatively affected by hyperglycemia, shown to be associated with increased IL6 levels (168) . In regard to tocilizumab safety, concerns have been raised about the risk of candidemia, septic shock and possible occurrence of intestinal perforation (an adverse effects reported in rheumatoid arthritis patients), which may be favored by the altered hemodynamics observed in critically ill COVID-19 patients (163, (169) (170) (171) . Based on these initial data, the efficacy and safety of tocilizumab in severe COVID-19 need to be corroborated by the results of the ongoing randomized controlled clinical trials. Clinical studies are also testing the other anti-IL6 receptor mAb sarilumab (FDA-and EMAapproved for rheumatoid arthritis) and anti-IL6 mAbs such as siltuximab (FDA-and EMA-approved for multicentric Castleman's disease) and the investigational mAb olokizumab. Like tocilizumab, sarilumab is able to bind both IL6R and sIL6R, but being a fully human mAb, has a lower risk of inducing neutralizing antibodies and allergic reactions compared to chimeric/humanized mAbs (172 strictly dependent on the JAK/STAT pathway (173, 174) , JAK inhibitors have also been used in COVID-19 patients with the aim of reducing the excessive inflammatory reaction. Among these, the orally administered ruxolitinib is a JAK1/JAK2 small-molecule inhibitor approved for the treatment of myelofibrosis, polycythemia vera, and graft-versus-host disease (175) . Consistently with its mechanism of action, in patients with myelofibrosis, ruxolitinib was able to reduce IL6 and TNFα levels and was well-tolerated (176 (177) . Furthermore, in COVID-19 patients two case reports of diffuse skin reactions with purpuras and a rapid decrease of hematocrit values were described (178) . Baricitinib is another JAK inhibitor that besides interrupting the JAK1/2-dependent signaling involved in cytokine-mediated inflammatory response to the SARS-Cov-2 infection, might also exert direct antiviral effects by blocking virus entry (see Section 2). Anakinra is a recombinant, non-glycosylated form of the natural occurring human interleukin- interferon-γ, which inhibits its binding to cell surface receptors and the subsequent activation of intracellular pro-inflammatory signaling pathways. Emapalumab is FDA-approved to treat the severe inflammatory condition of primary HLH in which serum interferon-γ levels are elevated (186). Blockade also immune responses against viruses, through enhancing antigen presentation, costimulation, and cytokine production by the effector cells of innate immune system, leading to enhanced adaptive immune responses (190) . The response mediated by type I interferons is more potent, rapid, transient, diffuse and inflammatory, whereas the type III interferon response is less potent, slower, sustained, anatomically restricted and less inflammatory (188) . Interestingly, the cytokine storm associated with COVID-19 is due to an uncontrolled response of the immune system to SARS-CoV2 viral infection that leads not to only to an excessive production of cytokines but also a diminished/delayed interferon response (191) (192) (193) . Based on preclinical studies and observations in SARS-CoV or MERS-CoV infected patients, the outcome of the interferon-mediated response to the viral infection seems to depend on the viral load and integrity of the host immune system. In particular, if the initial viral burden is low, type I interferons are promptly released and efficiently clear the infection; conversely, if the viral load is high or in elderly patients the early interferon production is hampered and a delayed interferon-mediated response may not only fail to control the infection but also result in inflammation and lung damage (194) . Thus, exogenously administered type I interferons would have protective effects as prophylaxis or in the early stage of SARS-CoV-2 infection, whereas they may deteriorate tissue injury and pneumonia when administration is delayed. Concerning the potential therapeutic role of interferon-λ, the lack of pro-inflammatory systemic effects would allow its safe administration also in an advanced phase of the infection (194) (195) (196) . Although better tolerated than type I interferons that may cause severe systemic side effects due to the ubiquitous expression of IFNAR, a possible disadvantage of interferon-λ is its lack of antiviral effects on infected alveolar macrophages or endothelial cells that do not express IFNLR1 but may serve as virus reservoir (197) . . In an additional trial, interferon-α1b as nasal drops is assessed for low-or high-risk medical staff exposed to SARS-CoV2 infected patients, as single agent or combined with thymosin α1, respectively [NCT04320238]. In regard to interferon-λ, the safety and efficacy of subcutaneous pegylated interferon-λ is tested as immediate/early therapy in non-critically ill hospitalized or ambulatory patients Another immunomodulating agent, fingolimod (FTY720), an orally administered drug approved for multiple sclerosis, was evaluated in COVID-19 patients (199) . Once absorbed, fingolimod undergoes phosphorylation to form an analog of the naturally occurring S1P, a lipid signaling molecule whose activity is mediated by the interaction with four subtypes of G protein-coupled receptors (S1P1 and S1P3-5) (200, 201) . After binding to S1P1, fingolimod initially activates the receptor and thereafter down-regulates its expression, causing retention of naïve T cells and central memory T cells in the lymph nodes and induction of lymphocytopenia (202) . Nevertheless, fingolimod does not substantially affect memory effector T cells, which play an important role in the defense against infectious agents (203) . Moreover, it does not affect humoral immune responses and does not prevent the generation of virus-specific cytotoxic T cells in the lymph nodes (203) . Thus, it has been hypothesized that patients on S1P modulators might have a reduced risk of complications from SARS-CoV-2 infection. Furthermore, due to the S1P role in lung endothelial cell integrity (204) , in COVID-19 patients, fingolimod might reduce vascular permeability and consequent lung injury (205) . In clinical trials with fingolimod for multiple sclerosis, conflicting results were reported showing either no change or increased risk of viral infections (especially herpes virus) compared controls (206) (207) (208) . Severe COVID-19 cases have been reported in patients with multiple sclerosis on treatment with fingolimod that was stopped upon SARS-CoV-2 diagnosis; in all these cases patients fully recovered from infection (205, 209, 210 Another molecule that has raised some interest to control the inflammatory response associated with SARS-CoV-2 infection is CD24Fc, a recombinant fusion protein that comprises CD24 attached to the Fc region of human IgG1. CD24 is a glycosylated membrane protein expressed in hematopoietic cells (including immature B and T cells, granulocytes, macrophages and some epithelial cells) that plays a regulatory role on B and T cell homeostasis (211) . In humans, CD24 is able to suppress inflammation upon interaction with the PRR Siglec10 and several danger-associated molecular patterns (DAMPs), helping to reduce the host immune response against proteins released by damaged cells. Preclinical studies demonstrated that the chimeric molecule CD24Fc mitigates the graft-versus-host disease, by decreasing the overall inflammatory response, and, in particular, the release of IL1β, IL6 and TNFα release (212) . These data provided the biological rationale for the clinical testing of CD24Fc also for COVID-19, and a randomized, double-blind, placebocontrolled, phase 3 study is currently recruiting severely ill infected patients [NCT04317040]. A cell-based approach to modulate the damage deriving from inflammation and altered activation of Dexamethasone is an old corticosteroid, i.e., a drug with broad anti-inflammatory and immunosuppressant activity that reduces cell-mediated immunity and various cytokine production. Its clinical indications span from pain in the joints to asthma, irritable bowel disease/Crohn disease, emesis, multiple sclerosis and various autoimmune diseases, as well as different types of cancer, to name just the most prevalent. It has also been used in the previous Although the clinical manifestations of COVID-19 are dominated by respiratory symptoms, the disease prognosis is largely influenced by the involvement of various organs, including the heart. Cardiovascular complications (i.e., myocardial infarction, acute heart failure and cardiomyopathy, shock and cardiac arrest, dysrhythmias, venous thromboembolic events, acute myocarditis) are associated with a high mortality rate and occur in about 10% of hospitalized patients (227) . Furthermore, patients with pre-existing cardiovascular diseases are predisposed to SARS-CoV-2-induced myocardial injury and infection is associated with a high mortality rate; in these patients, the risk of heart failure and myocardial damage increases to ≥35% (228) (229) (230) . The mechanisms involved in the cardiovascular injury of COVID-19 include: i) direct damage upon virus entry through ACE2 present in coronary endothelial cells, cardiomyocytes and cardiac fibroblasts; ii) increased oxygen consumption deriving from fever, enhanced adrenergic tone and tachycardia; iii) increased oxidative stress as a result of ROS production; iv) massive cytokine release and a state of hyperinflammation that contribute to pneumonia/ARDS with consequent acute heart failure, as well as endotheliitis leading to disseminated intravascular coagulation, thrombosis and infarction; v) SARS-CoV-2-induced ACE2 downregulation due to receptor shedding or internalization with consequent increase of angiotensin II (228, 231) . In fact, normally, ACE2 degrades angiotensin II to produce angiotensin 1-7 that is endowed with vasodilating and anti-inflammatory effects. Therefore, a reduction in ACE2 function after viral infection may result in a dysfunctional renin-angiotensin system, associated with an increase of angiotensin II, which would lead to vasoconstriction and inflammation. Dysregulated immunothrombosis (i.e., clot formation triggered by the interaction of innate immune system components, like macrophages, neutrophils and the complement system, with platelets and coagulation factors, that provides a first line defense against infectious agents) with diffuse microvascular thrombi formation has been also described in COVID-19 and involved in multi-organ damage (232, 233 In patients with severe COVID-19, high rates of venous thromboembolism and disseminated intravascular coagulation, due to dysregulation of the coagulation and fibrinolytic systems are Furthermore, heparin has anti-inflammatory properties by inhibiting IL6, IL8, TNFα release, c-reactive protein and adhesion of neutrophils to endothelial cells (241) (242) (243) . In a retrospective cohort study, the administration of LMWH to COVID-19 patients besides producing anticoagulant effects also reduced IL6 levels and increased lymphocyte counts suggesting a beneficial effect towards controlling the cytokine storm (244) . In addition, UFH and LMWH have been shown to inhibit the binding of the S protein of SARS-CoV-2 to its cellular receptor, ACE2, in an in vitro cell system expressing ACE2 and TMPRSS2. These results suggest another mechanism through which heparin may slow down or prevent disease progression in the early phases of COVID-19. (245, 246) . Fibrinolytic drugs, namely tissue-type plasminogen activator (tPA) as systemic intravenous treatment or as lung-targeted nebulizer form, have been proposed for COVID-19 patients (247, 248) . Several clinical trials are currently assessing different heparin regimens, other anticoagulants, systemic and local fibrinolytic approaches, and antiaggregants (e.g., rivaroxaban; defibrotide; clopidogrel, aspirin) (ClinicalTrials.gov). The PDE-5 inhibitor sildenafil, a vasodilator that is approved for treating erectile dysfunction and pulmonary arterial hypertension (249) , is also evaluated in a phase 3 trial for patients with mild to severe COVID-19 [NCT04304313]. In fact, sildenafil has a wide range of antiinflammatory, antioxidant, and vasodilatory actions resulting in cardioprotective effects and improved pulmonary circulation (250) (251) (252) . Aviptadil is a synthetic form of VIP that increases adenosine cyclase activity with consequent smooth muscle relaxation, approved in combination with phentolamine only in certain The VEGF-A is considered the most potent inducer of vascular permeability. The potential involvement of VEGF-A in COVID-19 has been related to the excessive production of angiotensin II, consequent to the SARS-CoV-2-mediated down-regulation of ACE2. In fact, angiotensin II is able to increase VEGF-A expression which in turn may exacerbate inflammation stimulating the recruitment of inflammatory cells and the release of proinflammatory cytokines (255) (256) (257) . Numerous studies have confirmed a key role of VEGF-A as potential therapeutic target in ALI and ARDS due do the increased vascular permeability and pulmonary edema (258) . Furthermore, VEGF-A has been involved in disruption of the blood-brain barrier and may contribute to brain inflammation in the course of SARS-CoV-2 infection (259 bleeding, delaying wound healing, thromboembolic events). All over the world, the scientific community is racing to evaluate a huge number of drugs or [46, 47] (see Table 2 ) EIDD-2801 Inhibition of RdRp -NCT04405739 NCT04405570 a NCT: ClinicalTrials.gov identifier Data from ClinicalTrials.gov accessed on June, 2020. Due to the rapidly evolving situation and the increasing number of clinical trials, the reported list of clinical trials does not mean to be exhaustive. b These agents might also have additional mechanisms contributing to the antiviral activity against SARS-CoV-2 RdRp; RNA-dependent RNA polymerase. Human coronaviruses with emphasis on the COVID-19 outbreak, Virusdisease. (2020) 1-5 A pneumonia outbreak associated with a new coronavirus of probable bat origin Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease-2019 (COVID-19): The epidemic and the challenges COVID-19 faecal-oral transmission: Are we asking the right questions? Enteric involvement of coronaviruses: is faecal-oral transmission of SARS-CoV-2 possible? Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1 The incubation period of coronavirus disease 2019 (COVID-19) from publicly reported confirmed cases: estimation and application Predictive symptoms and comorbidities for severe COVID-19 and intensive care unit admission: a systematic review and meta-analysis Three months of COVID-19: A systematic review and meta-analysis The trinity of COVID-19: immunity, inflammation and intervention Clinical characteristics of 82 death cases with COVID-19 SARS-CoV-2 can induce brain and spine demyelinating lesions Understanding pathways to death in patients with COVID-19 Comparing the Binding Interactions in the Receptor Binding Domains of SARS-CoV-2 and SARS-CoV SARS-CoV-2 entry in host cellsmultiple targets for treatment and prevention Properties of Coronavirus and SARS-CoV-2 Quantitative mRNA expression profiling of ACE 2, a novel homologue of angiotensin converting enzyme Tissue distribution of ACE2 protein, the functional receptor for SARS coronavirus. A first step in understanding SARS pathogenesis A novel angiotensin-converting enzyme-related carboxypeptidase (ACE2) converts angiotensin I to angiotensin 1-9 Angiotensin-converting enzyme 2 is an essential regulator of heart function Characterization of renal angiotensin-converting enzyme 2 in diabetic nephropathy The ACE2 expression in human heart indicates new potential mechanism of heart injury among patients infected with SARS-CoV-2 Characterization of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) spike glycoprotein-mediated viral entry Clinical features of 69 cases with coronavirus disease Arbidol combined with LPV/r versus LPV/r alone against corona virus disease 2019: a retrospective cohort study Arbidol monotherapy is superior to lopinavir/ritonavir in treating COVID-19 Umifenovir treatment is not associated with improved outcomes in patients with coronavirus disease 2019: a retrospective study Incidence of Adverse Drug Reactions in COVID-19 Patients in China: An Active Monitoring Study by Hospital Pharmacovigilance System Potential of Arbidol for Post-exposure Prophylaxis of COVID-19 Transmission-A Preliminary Report of a Retrospective Cohort Study Baricitinib as potential treatment for 2019-nCoV acute respiratory disease Baricitinib therapy in COVID-19: A pilot study on safety and clinical impact Baricitinib: a chance to treat COVID-19? Advances in the use of chloroquine and hydroxychloroquine for the treatment of COVID-19 Chloroquine is a potent inhibitor of SARS coronavirus infection and spread Hydroxychloroquine, a less toxic derivative of chloroquine, is effective in inhibiting SARS-CoV-2 infection in vitro In Vitro Antiviral Activity and Projection of Optimized Dosing Design of Hydroxychloroquine for the Treatment of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Remdesivir and chloroquine effectively inhibit the recently emerged novel coronavirus (2019-nCoV) in vitro Mechanisms of action of hydroxychloroquine and chloroquine: implications for rheumatology Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of COVID-19 associated pneumonia in clinical studies Efficacy of hydroxychloroquine in patients with COVID-19: results of a randomized clinical trial A pilot study of hydroxychloroquine in treatment of patients with moderate COVID-19. Zhejiang Da Xue Xue Bao Yi Xue Ban Retraction-Hydroxychloroquine or chloroquine with or without a macrolide for treatment of COVID-19: a multinational registry analysis Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial Early treatment of COVID-19 patients with hydroxychloroquine and azithromycin: A retrospective analysis of 1061 cases in Marseille, France CD147 as a Target for COVID-19 Treatment: Suggested Effects of Azithromycin and Stem Cell Engagement Azithromycin induces anti-viral effects in cultured bronchial epithelial cells from COPD patients TMPRSS2: Potential Biomarker for COVID Simultaneous treatment of human bronchial epithelial cells with serine and cysteine protease inhibitors prevents severe acute respiratory syndrome coronavirus entry Protease inhibitors targeting coronavirus and filovirus entry. Version 2 Identification of Nafamostat as a Potent Inhibitor of Middle East Respiratory Syndrome Coronavirus S Protein-Mediated Membrane Fusion Using the Split-Protein-Based Cell-Cell Fusion Assay Nafamostat Mesylate Blocks Activation of SARS-CoV-2: New Treatment Option for COVID-19 The Anticoagulant Nafamostat Potently Inhibits SARS-CoV-2 S Protein-Mediated Fusion in a Cell Fusion Assay System and Viral Infection In Vitro in a Cell-Type-Dependent Manner The effect of serine protease inhibitors on airway inflammation in a chronic allergen-induced asthma mouse model The serine protease inhibitor camostat inhibits influenza virus replication and cytokine production in primary cultures of human tracheal epithelial cells Cardiac arrest caused by nafamostat mesilate Three cases of treatment with Nafamostat in elderly patients with COVID-19 pneumonia who need oxygen therapy Potential new treatment strategies for COVID-19: is there a role for bromhexine as add-on therapy? In Silico Exploration of the Molecular Mechanism of Clinically Oriented Drugs for Possibly Inhibiting SARS-CoV-2's Main Protease Soluble angiotensin-converting enzyme 2: a potential approach for coronavirus infection therapy L-selective inhibitors: A potentially promising treatment for COVID-19 patients Glycopeptide Antibiotics Potently Inhibit Cathepsin L in the Late Endosome/Lysosome and Block the Entry of Ebola Virus, Middle East Respiratory Syndrome Coronavirus (MERS-CoV), and Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) Teicoplanin: an alternative drug for the treatment of COVID-19? Intensive Care COVID-19 Study Group of Sapienza University. Is teicoplanin a complementary treatment option for COVID-19? The question remains A Structural View of SARS-CoV-2 RNA Replication Machinery: RNA Synthesis, Proofreading and Final Capping SARS-coronavirus replication is supported by a reticulovesicular network of modified endoplasmic reticulum Dynamics of coronavirus replication-transcription complexes An Overview of Severe Acute Respiratory Syndrome-Coronavirus (SARS-CoV) 3CL Protease Inhibitors: Peptidomimetics and Small Molecule Chemotherapy Targeting the Dimerization of the Main Protease of Coronaviruses: A Potential Broad-Spectrum Therapeutic Strategy Old drugs as lead compounds for a new disease? Binding analysis of SARS coronavirus main proteinase with HIV, psychotic and parasite drugs Molecular dynamic simulations analysis of ritonavir and lopinavir as SARS-CoV 3CL(pro) inhibitors Why Are Lopinavir and Ritonavir Effective against the Newly Emerged Coronavirus 2019? Atomistic Insights into the Inhibitory Mechanisms A Trial of Lopinavir-Ritonavir in Adults Hospitalized with Severe Covid-19 Owa Lopinavir/ritonavir use in Covid-19 infection: is it completely non-beneficial? Factors associated with prolonged viral shedding and impact of Lopinavir/Ritonavir treatment in hospitalised non-critically ill patients with SARS-CoV-2 infection Early administration of ritonavir-boosted lopinavir could prevent severe COVID-19 Ul-Haq, Identification of chymotrypsinlike protease inhibitors of SARS-CoV-2 via integrated computational approach Lack of Antiviral Activity of Darunavir against SARS-CoV-2 Structural Similarity of SARS-CoV2 Mpro and HCV NS3/4A Proteases Suggests New Approaches for Identifying Existing Drugs Useful as COVID-19 Therapeutics Silico Evaluation of the Effectivity of Approved Protease Inhibitors against the Main Protease of the Novel SARS-CoV-2 Virus Recent discovery and development of inhibitors targeting coronaviruses Structure of the RNAdependent RNA polymerase from COVID-19 virus Mechanism of Inhibition of Ebola Virus RNA-Dependent RNA Polymerase by Remdesivir Remdesivir potently inhibits SARS-CoV-2 in human lung cells and chimeric SARS-CoV expressing the SARS-CoV-2 RNA polymerase in mice Prophylactic and therapeutic remdesivir (GS-5734) treatment in the rhesus macaque model of MERS-CoV infection Clinical benefit of remdesivir in rhesus macaques infected with SARS-CoV-2 Remdesivir: A Review of Its Discovery and Development Leading to Emergency Use Authorization for Treatment of COVID-19 Remdesivir is a direct-acting antiviral that inhibits RNA-dependent RNA polymerase from severe acute respiratory syndrome coronavirus 2 with high potency Structural basis of potential binding mechanism of remdesivir to SARS-CoV-2 RNA dependent RNA polymerase Coronavirus Susceptibility to the Antiviral Remdesivir (GS-5734) Is Mediated by the Viral Polymerase and the Proofreading Exoribonuclease Washington State 2019-nCoV Case Investigation Team. First Case of 2019 Novel Coronavirus in the United States Remdesivir for the Treatment of Covid-19 -Preliminary Report Remdesivir for 5 or 10 Days in Patients with Severe Covid-19 Remdesivir in adults with severe COVID-19: a randomised, double-blind, placebo-controlled, multicentre trial Compassionate Use of Remdesivir for Patients with Severe Covid-19 Compassionate Use of Remdesivir in Covid-19 Compassionate Use of Remdesivir in Covid-19 Compassionate Use of Remdesivir in Covid-19 Compassionate Use of Remdesivir in Covid-19 Compassionate remdesivir treatment of severe Covid-19 pneumonia in intensive care unit (ICU) and Non-ICU patients: Clinical outcome and differences in post-treatment hospitalisation status Remdesivir in Patients with Acute or Chronic Kidney Disease and COVID-19 Favipiravir, an anti-influenza drug against life-threatening RNA virus infections Favipiravir strikes the SARS-CoV-2 at its Achilles heel, the RNA polymerase, bioRxiv Experimental Treatment with Favipiravir for COVID-19: An Open-Label Control Study, Engineering (Beijing) Tenofovir against SARS-CoV-2 RNA dependent RNA polymerase (RdRp): A molecular docking study Virtual screening and repurposing of FDA approved drugs against COVID-19 main protease Mechanisms of action of ribavirin against distinct viruses Novel coronavirus treatment with ribavirin: Groundwork for an evaluation concerning COVID-19 Proteomics of SARS-CoV-2-infected host cells reveals therapy targets Triple combination of interferon beta-1b, lopinavir-ritonavir, and ribavirin in the treatment of patients admitted to hospital with COVID-19: an open-label, randomised, phase 2 trial Nitazoxanide/azithromycin combination for COVID-19: A suggested new protocol for early management Nucleotide Analogues as Inhibitors of SARS-CoV-2 Polymerase, bioRxiv An orally bioavailable broad-spectrum antiviral inhibits SARS-CoV-2 in human airway epithelial cell cultures and multiple coronaviruses in mice Small-Molecule Antiviral β-d-N4-Hydroxycytidine Inhibits a Proofreading-Intact Coronavirus with a High Genetic Barrier to Resistance Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China Characteristics and prognostic factors of disease severity in patients with COVID-19: The Beijing experience The many faces of the anti-COVID immune response COVID-19 as an Acute Inflammatory Disease COVID-19: Postmortem diagnostic and biosafety considerations Pathology of 2019 Novel Coronavirus Pneumonia: A Dynamic Disease Process Why tocilizumab could be an effective treatment for severe COVID-19? Version 2 Type I interferon gene induction by the interferon regulatory factor family of transcription factors Pathogen recognition and inflammatory signaling in innate immune defenses Weathering the COVID-19 storm: Lessons from hematologic cytokine syndromes The origin, transmission and clinical therapies on coronavirus disease 2019 (COVID-19) outbreak -an update on the status Exuberant elevation of IP-10, MCP-3 and IL-1ra during SARS-CoV-2 infection is associated with disease severity and fatal outcome, medRxiv Bidirectional relation between inflammation and coagulation Simultaneous presence of hypercoagulation and increased clot lysis time due to IL-1β, IL-6 and IL-8 Interleukin-6: designing specific therapeutics for a complex cytokine IL-6 biology: implications for clinical targeting in rheumatic disease Humanized antihuman IL-6 receptor antibody, tocilizumab The role of interleukin-6 in monitoring severe case of coronavirus disease 2019 Cytokine release syndrome in severe COVID-19: interleukin-6 receptor antagonist tocilizumab may be the key to reduce mortality Rational Use of Tocilizumab in the Treatment of Novel Coronavirus Pneumonia Off-label use of tocilizumab for the treatment of SARS-CoV-2 pneumonia in Impact of low dose tocilizumab on mortality rate in patients with COVID-19 related pneumonia TOCI-RAF Study Group. Efficacy and safety of tocilizumab in severe COVID-19 patients: a single-centre retrospective cohort study Pilot prospective open, single-arm multicentre study on off-label use of tocilizumab in patients with severe COVID-19 Tocilizumab therapy reduced intensive care unit admissions and/or mortality in COVID-19 patients Tocilizumab for the treatment of severe COVID-19 pneumonia with hyperinflammatory syndrome and acute respiratory failure: A single center study of 100 patients in Off-label Use of Tocilizumab in Patients with SARS-CoV-2 Infection Effective treatment of severe COVID-19 patients with tocilizumab Tocilizumab for Treatment of Severe COVID-19 Patients: Preliminary Results from SMAtteo COvid19 REgistry (SMACORE) Clinical Outcomes in COVID-19 Patients Treated with Tocilizumab: An Individual Patient Data Systematic Review Negative impact of hyperglycaemia on tocilizumab therapy in Covid-19 patients Tocilizumab for cytokine storm syndrome in COVID-19 pneumonia: an increased risk for candidemia? Intestinal perforation in patient with COVID-19 infection treated with tocilizumab and corticosteroids. Report of a clinical case Tocilizumab in COVID-19: Beware the risk of intestinal perforation Sarilumab: First Global Approval, Drugs Signaling Pathways in Inflammation and Anti-inflammatory Therapies JAK Inhibition as a New Treatment Strategy for Patients with COVID-19 Properties of FDA-approved small molecule protein kinase inhibitors: A 2020 update Efficacy and safety of ruxolitinib in the treatment of patients with myelofibrosis Managing side effects of JAK inhibitors for myelofibrosis in clinical practice Side effects of ruxolitinib in patients with SARS-CoV-2 infection: two case reports Inflammasome activation and Th17 responses Favorable anakinra responses in severe covid-19 patients with secondary hemophagocytic lymphohistiocytosis Safety and efficacy of early high-dose IV anakinra in severe COVID-19 lung disease Interleukin-1 blockade with high-dose anakinra in patients with COVID-19, acute respiratory distress syndrome, and hyper-inflammation: a retrospective cohort study Use of anakinra in severe COVID-19: a case report Interleukin-1 receptor antagonist anakinra in association with remdesivir in severe Coronavirus disease 2019: A case report Targeting the inflammatory cascade with anakinra in moderate to severe COVID-19 pneumonia: case series GM-CSF blockade with mavrilimumab in severe COVID-19 pneumonia and systemic hyperinflammation: a single-centre, prospective cohort study Shared and Distinct Functions of Type I and Type III Interferons Coronavirus infections and immune responses Immunomodulatory functions of type I interferons Dysregulation of type I interferon responses in COVID-19 Impaired type I interferon activity and exacerbated inflammatory responses in severe Covid-19 patients Imbalanced Host Response to SARS-CoV-2 Drives Development of COVID-19 Type I and Type III Interferons -Induction, Signaling, Evasion, and Application to Combat COVID-19 COVID-19: lambda interferon against viral load and hyperinflammation Weak Induction of Interferon Expression by SARS-CoV-2 Supports Clinical Trials of Interferon Lambda to Treat Early COVID-19 COVID-19 and emerging viral infections: The case for interferon lambda SARS-CoV-2 Receptor ACE2 Is an Interferon-Stimulated Gene in Human Airway Epithelial Cells and Is Detected in Specific Cell Subsets across Tissues The efficacy and safety of fingolimod in patients with relapsing multiple sclerosis: A meta-analysis Mechanism of action of oral fingolimod (FTY720) in multiple sclerosis Advances in oral immunomodulating therapies in relapsing multiple sclerosis An update on sphingosine-1-phosphate receptor 1 modulators Impact of sphingosine 1-phosphate modulation on immune outcomes Sphingosine-1-phosphate, FTY720, and sphingosine-1-phosphate receptors in the pathobiology of acute lung injury Severe COVID-19 infection in a patient with multiple sclerosis treated with fingolimod Oral fingolimod or intramuscular interferon for relapsing multiple sclerosis A placebo-controlled trial of oral fingolimod in relapsing multiple sclerosis Clinical pharmacology, efficacy, and safety aspects of sphingosine-1-phosphate receptor modulators COVID-19 infection in a patient with multiple sclerosis treated with fingolimod A fine balance: Immunosuppression and immunotherapy in a patient with multiple sclerosis and COVID-19 CD24 and Siglec-10 selectively repress tissue damage-induced immune responses Siglec-G represses DAMP-mediated effects on T cells Mesenchymal stem cells reduce inflammation while enhancing bacterial clearance and improving survival in sepsis Concise review: the surface markers and identity of human mesenchymal stem cells Mesenchymal Stromal Cells: Clinical Challenges and Therapeutic Opportunities Intrapulmonary delivery of bone marrow-derived mesenchymal stem cells improves survival and attenuates endotoxin-induced acute lung injury in mice Mesenchymal stem cells enhance survival and bacterial clearance in murine Escherichia coli pneumonia Generation of CD4+ or CD8+ regulatory T cells upon mesenchymal stem cell-lymphocyte interaction Human umbilical cord mesenchymal stem cells reduce systemic inflammation and attenuate LPS-induced acute lung injury in rats Pretreatment with mesenchymal stem cells reduces ventilator-induced lung injury Cell-based therapy to reduce mortality from COVID-19: Systematic review and meta-analysis of human studies on acute respiratory distress syndrome Transplantation of ACE2-Mesenchymal Stem Cells Improves the Outcome of Patients with COVID-19 Pneumonia Exosomes Derived from Bone Marrow Mesenchymal Stem Cells as Treatment for Severe COVID-19 Dexamethasone in Hospitalized Patients with Covid-19 -Preliminary Report Association between high serum total cortisol concentrations and mortality from COVID-19 Cardiovascular complications in COVID-19 COVID 19 and heart failure: from infection to inflammation and angiotensin II stimulation. Searching for evidence from a new disease COVID-19 and Multiorgan Response COVID-19 and the cardiovascular system Cardiovascular Complications in Patients with COVID-19: Consequences of Viral Toxicities and Host Immune Response Hyperinflammation and derangement of renin-angiotensin-aldosterone system in COVID-19: A novel hypothesis for clinically suspected hypercoagulopathy and microvascular immunothrombosis Increased cardiovascular mortality in African Americans with COVID-19 Will Complement Inhibition Be the New Target in Treating COVID-19-Related Systemic Thrombosis? Circulation. (2020) Eculizumab treatment in patients with COVID-19: preliminary results from real life ASL Napoli 2 Nord experience COVID and Coagulation: Bleeding and Thrombotic Manifestations of SARS-CoV2 Infection COVID-19 and Thrombotic or Thromboembolic Disease: Implications for Prevention, Antithrombotic Therapy, and Follow-up Pulmonary Embolism or Pulmonary Thrombosis in COVID-19? Is the Recommendation to Use High-Dose Heparin for Thromboprophylaxis Justified? Incidence of thrombotic complications in critically ill ICU patients with COVID-19 Abnormal coagulation parameters are associated with poor prognosis in patients with novel coronavirus pneumonia Anti-Inflammatory Effects of Heparin and Its Derivatives: A Systematic Review Efficacy of low molecular weight heparin in patients with acute exacerbation of chronic obstructive pulmonary disease receiving ventilatory support Unfractionated Heparin Alleviates Sepsis-Induced Acute Lung Injury by Protecting Tight Junctions The potential of low molecular weight heparin to mitigate cytokine storm in severe COVID-19 patients: a retrospective clinical study, medRxiv Unfractionated heparin potently inhibits the binding of SARS-CoV-2 spike protein to a human cell line BioRxiv Heparin inhibits cellular invasion by SARS-CoV-2: structural dependence of the interaction of the surface protein (spike) S1 receptor binding domain with heparin Tissue plasminogen activator (tPA) treatment for COVID-19 associated acute respiratory distress syndrome (ARDS): A case series Fibrinolytic abnormalities in acute respiratory distress syndrome (ARDS) and versatility of thrombolytic drugs to treat COVID-19 Pharmacotherapy for pulmonary arterial hypertension Sildenafil and cardioprotection Delivering Benefits at Speed Through Real-World Repurposing of Off-Patent Drugs: The COVID-19 Pandemic as a Case in Point Rationale for Their Utilization as Adjunctive Countermeasures in the Treatment of Coronavirus Disease 2019 (COVID-19) Pulmonary arterial hypertension: on the way to a manageable disease Why drugs fail in clinical trials in pulmonary arterial hypertension, and strategies to succeed in the future Increased renal vascular endothelial growth factor and angiopoietins by angiotensin II infusion is mediated by both AT1 and AT2 receptors Angiotensin-I converting enzyme inhibitors as potential anti-angiogenic agents for cancer therapy Our ACE in the HOLE: Justifying the Use of Angiotensin-converting Enzyme Inhibitors as Adjuvants to Standard Chemotherapy Vascular endothelial growth factor (VEGF) in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS): paradox or paradigm? Vascular Endothelial Growth Factor (VEGF) as a Vital Target for Brain Inflammation during the COVID-19 Outbreak Effectiveness of convalescent plasma therapy in severe COVID-19 patients Treatment of 5 Critically Ill Patients With COVID-19 With Convalescent Plasma Passive antibody therapy in COVID-19 Effect of Convalescent Plasma Therapy on Time to Clinical Improvement in Patients With Severe and Lifethreatening COVID-19: A Randomized Clinical Trial Challenges in the Production of Convalescent Hyperimmune Plasma in the Age of COVID-19 A human monoclonal antibody blocking SARS-CoV-2 infection We would like to acknowledge the support of the "Fondazione AIRC" to the National Civil Protection to help tackle the COVID-19 emergency in Italy and its commitment to continue supporting cancer research during the challenging times of SARS-CoV-2 pandemic. G.Graziani is Principal Investigator (PI) of the AIRC grant IG 2017 -ID. 20353 project. Orphan drug for the treatment of ARDS, ALI and sarcoidosis NCT04311697 NCT04360096Anti-VEGF-A Bevacizumab Cancer treatment; age-related macular degeneration (off-label) NCT04305106 NCT04344782 NCT04275414 a NCT: ClinicalTrials.gov identifier Data from ClinicalTrials.gov accessed on June, 2020. Due to the rapidly evolving situation and the increasing number of clinical trials, the reported list of clinical trials does not mean to be exhaustive.ARDS: acute respiratory distress syndrome; ALI: acute lung injury.