WO2022079250A1

WO2022079250A1 - Compounds for the treatment of viral infections

Info

Publication number: WO2022079250A1
Application number: PCT/EP2021/078628
Authority: WO
Inventors: Ulrich Betz; Lars Burgdorf; Dirk Finsinger; Markus Klein; Sven Carsten POETZSCH
Original assignee: Merck Patent Gmbh
Priority date: 2020-10-16
Filing date: 2021-10-15
Publication date: 2022-04-21

Abstract

The present invention encompasses Syk inhibitor for use in the treatment of coronavirus infections, including COVID-19, alone or in combination with one or more additional therapeutic agents.

Description

COMPOUNDS FOR THE TREATMENT OF VIRAL INFECTIONS

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention provides for the use of inhibitors of the kinase SYK (Spleen Tyrosine Kinase) in the treatment of coronavirus infections, including SARS-CoV infections such as COVID-19.

BACKGROUND OF THE INVENTION

Syk inhibitors

[0002] Syk (spleen tyrosine kinase) is a 72 kDa non-receptor tyrosine kinase that is expressed throughout the hematopoietic lineage, as well as in various other cell types ranging from fibroblasts, osteoclasts and hepatocytes to epithelial and neuronal cells (Mocsai, et al., Nat Rev Immunol. 2010; 10(6): 387-402). As a major regulator of both Fc receptor signalling and B cell receptor signalling, Syk plays a central role in the adaptive immune system. In addition, Syk is involved in the regulation of diverse other cellular events, including cellular adhesion, innate immune recognition, osteoclast maturation, platelet activation and vascular development. More recently, it has been shown that Syk is also a promoter of cell survival in various cancer cell types.

[0003] The involvement of Syk in various critical cellular processes makes the kinase an attractive drug target for the treatment of various physiological conditions, ranging from autoimmune diseases and type I diabetes to ischemia-reperfusion injury and cancer (Geahlen, Trends Pharmacol Sci. 2014; 35(8): 414-422).

Coronaviruses

[0004] Coronaviruses (CoVs) are positive-sense, single-stranded RNA (ssRNA) viruses of the order Nidovir ales, in the family Coronaviridae . There are four sub-types of coronaviruses - alpha, beta, gamma and delta - with the Alphacoronaviruses and Betacoronaviruses infecting mostly mammals, including humans. Over the last two decades, three significant novel coronaviruses have emerged which jumped from non-human mammal hosts to infect humans: the severe acute respiratory syndrome (SARS-CoV-1) which appeared in 2002, Middle East respiratory syndrome (MERS-CoV) which appeared in 2012, and COVID-19 (SARS-CoV-2) which appeared in late 2019. By mid- June of 2020, over 7.8 million people are known to have been infected, and over 432,000 people have died. Both numbers likely represent a significant undercount of the devastation wrought by the disease. COVID-19

[0005] SARS-CoV-2 closely resembles SARS-CoV-1, the causative agent of the SARS epidemic of 2002-03 (Fung, et al., Annu. Rev. Microbiol. 2019. 73:529-57). Severe disease has been reported in approximately 15% of patients infected with SARS-CoV-2, of which one third progress to critical disease (e.g. respiratory failure, shock, or multiorgan dysfunction (Siddiqi, et al., J. Heart and Lung Trans. (2020), doi: https://doi.Org/10.1016/j.healun.2020.03.012, Zhou, et al., Lancet 2020; 395: 1054-62. https://doi.org/10.1016/S0140-6736(20)30566-3). Fully understanding the mechanism of viral pathogenesis and immune responses triggered by SARS-CoV-2 would be extremely important in rational design of therapeutic interventions beyond antiviral treatments and supportive care. Much is still being discovered about the various ways that COVID-19 impacts the health of the people that develop it.

[0006] Severe acute respiratory syndrome (SARS)-Corona Virus-2 (CoV-2), the etiologic agent for coronavirus disease 2019 (COVID-19), has caused a pandemic affecting almost eight million people worldwide with a case fatality rate of 2-4% as of June 2020. The virus has a high transmission rate, likely linked to high early viral loads and lack of pre-existing immunity (He, et al., Nat Med 2020 https://doi.org/10.1038/s41591-020-0869-5). It causes severe disease especially in the elderly and in individuals with comorbidities. The global burden of COVID- 19 is immense, and therapeutic approaches are increasingly necessary to tackle the disease. Intuitive anti-viral approaches including those developed for enveloped RNA viruses like HIV- 1 (lopinavir plus ritonavir) and Ebola virus (remdesivir) have been implemented in testing as investigational drugs (Grein et al., NEJM 2020 https://doi.org/10.1056/NEJMoa2007016; Cao, et al., NEJM 2020 DOI: 10.1056/NEJMoa2001282). But given that many patients with severe disease present with immunopathology, host-directed immunomodulatory approaches are also being considered, either in a staged approach or concomitantly with antivirals (Metha, et al., The Lancet 2020; 395(10229) DOI: https://doi.org/10.1016/80140-6736(20)30628-0, Stebbing, et al., Lancet Infect Dis 2020. https://doi.org/10.1016/S 1473-3099(20)30132-8).

[0007] While there are multiple therapies being considered for use in treatment of COVID- 19, there is still an urgent need for novel therapies to address the different stages of the SARS- CoV-2 infectious cycle (Siddiqi, et al.). BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 shows the following: A) Representative images from dimethyl sulfoxide (DMSO)- resp. remdesivir-treated wells. Infected (arrow) and uninfected (arrowhead) cells are indicated; 500 pm and 50 pm scale bars are shown in the composite and magnified images, respectively. Raw and normalized (Norm.) values calculated from the images are shown. B) Box and whiskers plot of SARS-CoV-2 assay control ECsos obtained from independent biological experiments with mean indicated with a bar and all data points shown. Whiskers indicate minimums and maximums. C) Dose response curves for the remdesivir, apilimod and puromycin control compounds run as part of hit reconfirmation showing 1) % infected cells (in blue, marked with *), 2) total cells per well in the HeLa-ACE2/SARS-CoV-2 infection assay (in orange, marked with #), and 3) live cells per well in the uninfected HeLa-ACE2 counterscreen cytotoxicity assay (in magenta, marked with f).

Figure 2 shows % infected cells (in blue), total cells per well in the HeLa-ACE2/SARS-CoV- 2 infection assay (in orange), and live cells per well in the uninfected HeLa-ACE2 counterscreen cytotoxicity assay (in magenta).

SUMMARY OF THE INVENTION

[0009] In a first aspect, the invention provides Syk inhibitors for use in the treatment of viral infections in a subject in need thereof. In one embodiment, said treatment is an anti-viral treatment. In one embodiment, the viral infection is a single-strand RNA viral infection. In another embodiment, the viral infection is a coronavirus infection. In a further embodiment, the viral infection is a SARS-CoV-1, MERS-CoV, or SARS-CoV-2 infection. In a further embodiment, the viral infection is a SARS-CoV-2 infection.

[0010] A second aspect is a method of treating a coronavirus infection in a subject in need thereof, comprising administering an effective amount of a Syk inhibitor, or a pharmaceutically acceptable salt thereof, to the subject. In one embodiment, said treatment is an anti-viral treatment. In one embodiment, the administration of the Syk inhibitor reduces the viral load in the subject. In one embodiment, the Syk inhibitor is administered prior to COVID-19 pneumonia development. In some embodiments, the Syk inhibitor is administered prior to the subject developing a severe cytokine storm. In some embodiments, the subject has a mild to moderate SARS-CoV-2 infection. In some embodiments, the subject is asymptomatic at the start of the administration regimen. [0011] A third aspect relates to the use of a Syk inhibitor for the manufacture of a medicament for the treatment of viral infections. In one embodiment, said treatment is an antiviral treatment.

DETAILED DESCRIPTION

[0012] At the initial antiviral response phase, when the virus primarily infects ACE2- expressing specialized epithelial cells (type II pneumocytes) in the lung alveoli, direct antiviral or immune-enhancing therapy (e.g. IFN-I, including Rebif) may prove to be of benefit in minimizing contagion and preventing progression to severe disease (Hoffmann, et al., Cell 2020. DOI: https://doi.Org/10.1016/j.cell.2020.02.052; Sungnak, et al., Qbio preprint; arXiv:2003.06122 [q-bio.CB]; Zou, et al., Front Med 2020 https://doi.org/10.1007/sl l684- 020-0754-0; Zhao, et al., BioRxv preprint https://doi.org/10.1101/2020.01.26.9 l 9985^Qi, et al., BBRC 2020 https://doi.Org/10.1016/j.bbrc.2020.03.044; Taccone, et al., Lancet Resp. Med. (2020) https ://doi . org/ 10.1016/S2213 -2600(20)30172-7).

[0013] Recent papers have suggested a correlation between SARS-CoV-2 viral load, symptom severity and viral shedding (He, et al.; Liu, et al., Lancet Infect Dis 2020. https://doi.org/10.1016/S1473-3099(20)30232-2). Some antiviral drugs administered at symptom onset to blunt coronavirus replication are in the testing phase (Grein, et al.; Taccone, et al.), but as yet none have shown much promise.

[0014] SARS-CoV-2 directly enters cells expressing ACE2 via receptor-mediated endocytosis (Hoffmann, et al.). Successful viral replication requires host endosome acidification to release the viral genome into the host cytosol. Innate immune cells like monocytes, macrophages and neutrophils do not highly express ACE2, but have abundant Fc receptors (Zou, et al.; Qi, et al.; Lu, et al., Nat. Rev. Imm. 2018 https://doi.org/10.1038/nri.2017.106). In stage II, antibodies that bind the virus, can mediate viral uptake into myeloid cell endosomes via Fc receptors (FcR) or complement receptors (CR) (Lu, et al.; Dandekar, et al., Nat. Rev. Imm. 2005, https://doi.org/10.1038/nril732). Thus ACE2, FcR and CR present three mechanisms how SARS-CoV-2 can enter endosomes and trigger hyperinflammation leading to cytokine storm and severe disease. Additionally, ssRNA virus can induce NETosis in neutrophils (Saitoh, et al., Cell Host Microbe (2012), 19; 12(1): 109-16) leading to release of DNA and RNA, creating a feed-forward loop to further fuel inflammation (Herster et al., Nat Commun 2020; 11, 105 https://doi.org/10.1038/s41467- 019-13756-4), which has been proposed as a driver of severe COVID-19 (Barnes, et al., J Exp med 2020; 217 (6) https://doi.org/10.1084/jem.20200652). SARS-CoV-1 derived ssRNA has been shown to mediate severe lung pathology in animal models and presents as a potential driver of virus-associated cytokine storm (Li, et al., Microbes Infect 2013; 15 (2) 88-95. https://doi.Org/10.1016/j.micinf.2012.10.008).

[0015] Some patients infected with SARS-CoV-2 develop in the course of disease progression severe lung pathology as well as other organ dysfunction including myocardial injury, acute kidney injury, shock resulting in endothelial dysfunction and subsequently micro and macrovascular thrombosis. These organ dysfunctions are assumed to be caused by a hyperinflammatory immune response. Accordingly, Syk inhibitors have been suggested as possible treatment to control the hyperinflammatory response at the later stages of SARS-CoV- 2 disease progression.

[0016] All steps of the viral life cycle of SARS-CoV-2, including the attachment of viral particles to cells, cellular entry of the virus, replication, transcription, viral assembly and release of new viruses require various interactions between virus components and cellular functions. Since Syk regulates diverse cellular processes, the present inventors speculated that Syk inhibition may, independent of its effect on the immune system, have the capacity to affect the life cycle of SARS-CoV-2, reduce the viral load in cells infected with SARS-CoV-2 and/or reduce the number of cells infected with SARS-CoV-2 virus. Thus, Syk inhibitors may provide for effects at the early stages of infection that may allow a subject infected with SARS-CoV-2 to avoid severe disease.

[0017] When testing certain Syk inhibitor in the experiments described in the examples below, the present inventors have surprisingly found that these Syk inhibitors are highly effective against SARS-CoV-2-infected cells. This treatment effect is achieved independent of the effects of the Syk inhibitors on immune cells. Whatever the exact mechanism of action for the antiviral properties of the Syk inhibitors according to the present disclosure, it is proposed that administration thereof may have one or more clinical benefits, as described further herein. Since these effects are independent of the effects of Syk inhibitors on immune cells, this allows, in addition to the use of Syk inhibitors for controlling the excessive immune response at later stages of the disease, for the use of Syk inhibitors to treat the viral infection at early stages of the disease where no excessive immune response occurs.

[0018] "Syk inhibitor" refers to a compound that has a biological effect to inhibit, significantly reduce or down-regulate the biological activity of Syk (spleen tyrosine kinase). In some embodiments, the Syk inhibitor specifically binds to Syk and inhibits the kinase activity of Syk. In some embodiments, the term "Syk inhibitor" refers specifically to the compounds defined in items [9], [10] or [11] below. In some embodiments, the term "Syk inhibitor" refers specifically to the compounds defined in Table 1 below.

[0019] COVID-19” is the name of the disease which is caused by a SARS-CoV-2 infection. While care was taken to describe both the infection and disease with accurate terminology, “COVID-19” and “SARS-CoV-2 infection” are meant to be equivalent terms.

[0020] As of the writing of this application, the determination and characteristics of the severity of COVID-19 patients/symptoms has not been definitively established. However, in the context of this invention, “mild to moderate” COVID-19 occurs when the subject presents as asymptomatic or with less severe clinical symptoms (e.g., low grade or no fever (<39.1 °C), cough, mild to moderate discomfort) with no evidence of pneumonia, and generally does not require medical attention. When “moderate to severe” infection is referred to, generally patients present with more severe clinical symptoms (e.g., fever >39.1 °C, shortness of breath, persistent cough, pneumonia, etc.). As used herein “moderate to severe” infection typically requires medical intervention, including hospitalization. During the progression of disease, a subject can transition from “mild to moderate” to “moderate to severe” and back again in one course of bout of infection.

[0021] Treatment of COVID-19 using the methods of this invention include administration of an effective amount of a Syk inhibitor of the invention at any stage of the infection, preferably an early stage of the infection, to prevent or reduce the symptoms associated therewith. Typically, subjects will be administered an effective amount of a Syk inhibitor of the invention after definitive diagnosis and presentation with symptoms consistent with a SARS-CoV2 infection, and administration will reduce the severity of the infection and/or prevent progression of the infection to a more severe state. The clinical benefits upon such administration is described in more detail in the sections below. 1. Compounds and Definitions

[0022] In one embodiment, the Syk inhibitor is a compound according to Formula (A)

Formula (A) wherein

A is at each occurrence independently selected from the group consisting of N and CH;

T is selected from the group consisting of H, NH2 and CH3, wherein 1 to

3 H atoms of said CH3 may be replaced by F;

I is selected from the group consisting of P¹, P² and P³;

U is a group defined by formula xa), formula xb), formula xc) or formula xd), wherein said group defined by formula xa), formula xb), formula xc) or formula xd) is unsubstituted or mono-, di- or tri substituted by Hal, CN, OR^3a, N(R^3a)2, NHR^3a and/or R^3a, wherein 1, 2 or 3 of the cyclic CH2 groups may be independently replaced by C=O, O, S, NR^3a, SO and/or SO2;

P¹ is a Cs-Cs-cycloalkyl which is unsubstituted or mono-, di-, tri- or tetrasubstituted by Hal, CN, OH, NH2, NHR^3a, N(R^3a)2, OR^3a and/or R^3a;

P² is selected from the group consisting of phenyl and an aromatic monocyclic 5-, 6- or 7-membered heterocycle, wherein the heterocyclic system of said aromatic monocyclic 5-, 6- or 7-membered heterocycle contains 1, 2 or 3 N, O and/or S atoms, wherein said phenyl or aromatic monocyclic 5-, 6- or 7-membered heterocycle is unsubstituted or mono-, di-, tri- or tetrasubstituted by Hal, Het, CN, OH, NH₂, NHR^3a, N(R^3a)₂, OR^3a and/or R^3a;

P³ is a bicyclic 9- or 10-membered heterocycle, wherein the heterocyclic system contains 1, 2 or 3 N, O and/or S atoms, wherein at least one ring of said bicyclic 9- or 10-membered heterocycle is aromatic, and wherein said bicyclic 9- or 10-membered heterocycle is unsubstituted or mono-, di-, tri-, or tetrasubstituted by Hal, CN, OH, NH2, NHR^3a, N(R^3a)₂, OR^3a, and/or R^3a;

Vi is selected from the group consisting of NH and O;

V2 is selected from the group consisting of NH2, OH, NHR^3a, N(R^3a)2 and

OR^3a;

R^3a, R^3b are, independently from one another, selected from the group consisting of the group consisting of a linear or branched Ci-Ce-alkyl or C3-C8 cycloalkyl, wherein 1 to 5 H atoms may be replaced by Hal, CN, OH and/or OAlk;

Het is a 5-membered aromatic heterocycle wherein the heterocyclic system contains 1, 2 or 3 N, O and/or S atoms.

[0023] Such compounds can be prepared by standard methods of synthetic organic chemistry (see e.g. March's Advanced Organic Chemistry, 8th ed. (2020), John Wiley & Sons, Inc., Hoboken, NJ, U.S.A.). The general synthetic accessibility of such compounds is described in WO 2014/023385 Al. Similar compounds can be prepared by using appropriate building blocks. [0024] In one embodiment, the Syk inhibitor is a compound according to Formula (A)

Formula (A) wherein

A is N;

T is selected from the group consisting of H, NH2 and CHF2;

I is selected from the group consisting of P¹, P² and P³;

P¹ is cyclohexyl which is unsubstituted or mono-, di-, tri- or tetrasubstituted by Hal, CN, OH, NH2, NHR^3a, N(R^3a)2, OR^3a and/or R^3a;

P² is selected from the group consisting of phenyl and 4-pyrazolyl, wherein said phenyl or 4-pyrazolyl is unsubstituted or mono-, di-, trior tetrasubstituted by Hal, Het, CN, OH, NH₂, NHR^3a, N(R^3a)₂, OR^3a and/or R^3a;

which is unsubstituted or mono-, di-, tri-, or tetrasubstituted by Hal, CN, OH, NH₂, NHR^3a, N(R^3a)₂, OR^3a and/or R^3a;

Vi is NH;

V₂ is selected from the group consisting of NH₂ and OH;

R^3a, R^3b are, independently from one another, selected from the group consisting of the group consisting of a linear or branched Ci-Ce-alkyl or Cs-Cs cycloalkyl, wherein 1 to 5 H atoms may be replaced by Hal, CN, OH and/or OAlk;

[0025] Such compounds can be prepared by standard methods of synthetic organic chemistry (see e.g. March's Advanced Organic Chemistry, 8th ed. (2020), John Wiley & Sons, Inc., Hoboken, NJ, U.S.A.). The general synthetic accessibility of such compounds is described in WO 2014/023385 Al. Similar compounds can be prepared by using appropriate building blocks.

[0026] In one embodiment, the Syk inhibitor is a compound according to Formula (A)

Formula (A) wherein

A is N;

T is selected from the group consisting of H, NH2 and CHF2;

I is selected from the group consisting of P¹, P² and P³;

U denotes a group of formula xa), xb), xc), xd) each, independently from one another, unsubstituted or mono-, di- or tri substituted by Hal, CN, OR^3a, N(R^3a)2, NHR^3a and/or R^3a, wherein 1, 2 or 3 of the cyclic CH2 groups may be replaced by C=O, O, S, NR^3a, SO and/or SO2;

xd):

P³ is

Vi is NH;

V2 is selected from the group consisting of NH2 and OH;

[0027] Such compounds can be prepared by standard methods of synthetic organic chemistry (see e.g. March's Advanced Organic Chemistry, 8th ed. (2020), John Wiley & Sons, Inc., Hoboken, NJ, U.S.A.). The general synthetic accessibility of such compounds is described in WO 2014/023385 Al. Similar compounds can be prepared by using appropriate building blocks. [0028] In one embodiment, the Syk inhibitor is a compound selected from Table 1 below:

Table 1:

13

SUBSTITUTE SHEET (RULE 26)

SUBSTITUTE SHEET (RULE 26)

SUBSTITUTE SHEET (RULE 26)

Disclosed herein are also the Compounds 1 to 31 as such.

Such compounds can be prepared by standard methods of synthetic organic chemistry (see e.g. March's Advanced Organic Chemistry, 8th ed. (2020), John Wiley & Sons, Inc., Hoboken, NJ, U.S.A.). The general synthetic accessibility of such compounds is described in WO 2014/023385 Al. Similar compounds can be prepared by using appropriate building blocks. [0029] In one embodiment, the Syk inhibitor is a compound according to Formula (1):

The compound according to Formula (1) is referred to herein also as "Compound 1". This compound is a pyridopyrimidine derivative and may also be referred to as 3-[2-((lR,2S)-2- Amino-cyclohexylamino)-5-difluoromethyl-pyrido[4,3-d]pyrimidin-8-yl]-lH-indole-6- carbonitrile. It is disclosed and further characterized in published international patent application WO 2014/023385 Al (see Example 87).

[0030] One embodiment of the present disclosure is the use of a compound according to Formula (A) as defined above or a pharmaceutically acceptable salt and/or solvate or hydrate thereof for the treatment of a viral infection.

[0031] One embodiment of the present disclosure is the use of a compound according to Formula (1) to (31) or a pharmaceutically acceptable salt and/or solvate or hydrate thereof for the treatment of a viral infection.

[0032] One embodiment of the present disclosure is the use of a compound according to Formula (1) or a pharmaceutically acceptable salt and/or solvate or hydrate thereof for the treatment of a viral infection.

[0033] The Syk inhibitor used in the treatment of the present disclosure can e.g. be a Compound according to Formula (A) as defined above, in particular a Compound according to Formula (1) to (31) as defined above.

[0034] Syk inhibitors, such as a Compound according to Formula (A) as defined above, in particular one of the Compounds 1 to 31, may either be used in their free form or as pharmaceutically acceptable salts. Such pharmaceutically acceptable salts can be derived from various organic and inorganic acids and bases by procedures known in the art. Pharmaceutically acceptable salt forms of Syk inhibitors, and in particular of a Compound according to Formula (A) as defined above, in particular of one of the compounds of Formula (1) to (31), are for the most part prepared by conventional methods.

[0035] If a Syk inhibitor used in the present invention contains a carboxyl group, one of its suitable salts can be formed by reacting the compound with a suitable base to give the corresponding base-addition salt. Such bases are, for example, alkali metal hydroxides, including potassium hydroxide, sodium hydroxide and lithium hydroxide; alkaline earth metal hydroxides, such as barium hydroxide and calcium hydroxide; alkali metal alkoxides, for example potassium ethoxide and sodium propoxide; and various organic bases, such as piperidine, diethanolamine and N methylglutamine. The aluminium salts of Syk inhibitors according to the present disclosure are likewise included.

[0036] In the case of certain Syk inhibitors, such as the compounds of Formula (1), acidaddition salts can be formed by treating these compounds with pharmaceutically acceptable organic and inorganic acids, for example hydrogen halides, such as hydrogen chloride, hydrogen bromide or hydrogen iodide, other mineral acids and corresponding salts thereof, such as sulfate, nitrate or phosphate and the like, and alkyl- and monoaryl-sulfonates, such as ethanesulfonate, toluenesulfonate and benzenesulfonate, and other organic acids and corresponding salts thereof, such as acetate, trifluoro-acetate, tartrate, maleate, succinate, citrate, benzoate, salicylate, ascorbate and the like. Accordingly, pharmaceutically acceptable acid-addition salts of the compound of Formula (1) include the following: acetate, adipate, alginate, arginate, aspartate, benzoate, benzenesulfonate (besylate), bisulfate, bisulfite, bromide, butyrate, camphorate, camphorsulfonate, caprylate, chloride, chlorobenzoate, citrate, cyclopentane propionate, digluconate, dihydrogenphosphate, dinitrobenzoate, dodecyl sulfate, ethane-sulfonate, formate, fumarate, galacterate (from mucic acid), galacturonate, glucoheptanoate, gluconate, glutamate, glycerophosphate, hemi succinate, hemisulfate, heptanoate, hexanoate, hippurate, hydrochloride, hydro-bromide, hydroiodide, 2- hydroxyethanesulfonate, iodide, isethionate, iso-butyrate, lactate, lactobionate, malate, maleate, malonate, mandelate, metaphosphate, methanesulfonate, methylbenzoate, monohydrogenphosphate, 2-naphthalenesulfonate, nicotinate, nitrate, oxalate, oleate, palmoate, pectinate, persulfate, phenylacetate, 3 -phenylpropionate, phosphate, phosphonate, phthalate, but this does not represent a restriction.

[0037] Furthermore, the base salts of the Syk inhibitors that may be used in the present disclosure include aluminium, ammonium, calcium, copper, iron(III), iron(II), lithium, magnesium, manganese(III), manganese(II), potassium, sodium and zinc salts, but this is not intended to represent a restriction. Of the above-mentioned salts, preference is given to ammonium; the alkali metal salts sodium and potassium, and the alkaline earth metal salts calcium and magnesium. Salts of Syk inhibitors which are derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary and tertiary amines, substituted amines, also including naturally occurring substituted amines, cyclic amines, and basic ion exchanger resins, for example arginine, betaine, caffeine, chloroprocaine, choline, N,N'-dibenzylethylenediamine (benzathine), dicyclohexylamine, diethanol-amine, diethylamine, 2 diethylaminoethanol, 2 dimethylaminoethanol, ethanolamine, ethylenediamine, N ethylmorpholine, N ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lido-caine, lysine, meglumine, N-methyl-D-glucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethanol-amine, triethylamine, trimethylamine, tripropylamine and tris(hydroxy- methyl)methylamine (tromethamine), but this is not intended to represent a restriction.

[0038] Syk inhibitors which contain basic nitrogen-containing groups can be quaternized using agents such as (Cl-C4)alkyl halides, for example methyl, ethyl, isopropyl and tert-butyl chloride, bromide and iodide; di(Cl-C4)alkyl sulfates, for example dimethyl, diethyl and diamyl sulfate; (C10-C18)alkyl halides, for example decyl, dodecyl, lauryl, myristyl and stearyl chloride, bromide and iodide; and aryl-(Cl-C4)alkyl halides, for example benzyl chloride and phenethyl bromide. Both water- and oil-soluble compounds according to the invention can be prepared using such salts.

[0039] The above-mentioned pharmaceutical salts which are preferred include acetate, trifluoroacetate, besylate, citrate, fumarate, gluconate, hemi succinate, hippurate, hydrochloride, hydrobromide, isethionate, mandelate, meglumine, nitrate, oleate, phosphonate, pivalate, sodium phosphate, stearate, sulfate, sulfosalicylate, tartrate, thiomalate, tosylate and tromethamine, but this is not intended to represent a restriction.

[0040] Particular preference is given to hydrochloride, di hydrochloride, hydro-bromide, maleate, mesylate, phosphate, sulfate and succinate.

[0041] The acid-addition salts of basic Syk inhibitors, such as the compound according to Formula (1), are prepared by bringing the free base form into contact with a sufficient amount of the desired acid, causing the formation of the salt in a conventional manner. The free base can be regenerated by bringing the salt form into contact with a base and isolating the free base in a conventional manner. The free base forms differ in a certain respect from the corresponding salt forms thereof with respect to certain physical properties, such as solubility in polar solvents; for the purposes of the invention, however, the salts otherwise correspond to the respective free base forms thereof.

[0042] As mentioned, the pharmaceutically acceptable base-addition salts of the Syk inhibitors formed with metals or amines, such as alkali metals and alkaline earth metals or organic amines. Preferred metals are sodium, potassium, magnesium and calcium. Preferred organic amines are N,N’ -dibenzylethylenediamine, chloroprocaine, choline, diethanol-amine, ethylenediamine, N-methyl-D-glucamine and procaine.

[0043] The base-addition salts of acidic compounds according to the invention are prepared by bringing the free acid form into contact with a sufficient amount of the desired base, causing the formation of the salt in a conventional manner. The free acid can be regenerated by bringing the salt form into contact with an acid and isolating the free acid in a conventional manner. The free acid forms differ in a certain respect from the corresponding salt forms thereof with respect to certain physical properties, such as solubility in polar solvents; for the purposes of the invention, however, the salts otherwise correspond to the respective free acid forms thereof.

[0044] If a Syk inhibitor according to the present disclosure contains more than one group which is capable of forming pharmaceutically acceptable salts of this type, the invention also encompasses multiple salts. Typical multiple salt forms include, for example, bitartrate, diacetate, difumarate, dimeglumine, di-phosphate, disodium and trihydrochloride, but this is not intended to represent a restriction.

[0045] With regard to that stated above, it can be seen that the expression "pharmaceutically acceptable salt” in the present connection is taken to mean an active ingredient which comprises a Syk inhibitor, such as a Compound according to Formula (A) as defined above, the compound according to Formula (1) or any other of Compounds 1 to 31, in the form of one of its salts, in particular if this salt form imparts improved pharmacokinetic properties on the active ingredient compared with the free form of the active ingredient or any other salt form of the active ingredient used earlier. The pharmaceutically acceptable salt form of the active ingredient can also provide this active ingredient for the first time with a desired pharmacokinetic property which it did not have earlier and can even have a positive influence on the pharmacodynamics of this active ingredient with respect to its therapeutic efficacy in the body. [0046] Additionally, unless otherwise stated, structures depicted herein are also meant to include compounds that differ only in the presence of one or more isotopically enriched atoms. For example, compounds having the present structures including the replacement of hydrogen by deuterium or tritium, or the replacement of a carbon by a ¹³C- or ¹⁴C-enriched carbon are within the scope of this invention. In some embodiments, the group comprises one or more deuterium atoms.

[0047] In some embodiments of said uses of said Syk inhibitor described herein, said Syk inhibitor is a Syk inhibitor as defined, but not a pharmaceutically acceptable salt or solvate or hydrate thereof.

2. Uses, Formulation and Administration

[0048] The term “patient” or “subject”, as used herein, means an animal, preferably a human. However, “subject” can include companion animals such as dogs and cats. In one embodiment, the subject is an adult human patient. In another embodiment, the subject is a pediatric patient. Pediatric patients include any human which is under the age of 18 at the start of treatment. Adult patients include any human which is age 18 and above at the start of treatment. In one embodiment, the subject is a member of a high-risk group, such as being over 65 years of age, immunocompromised humans of any age, humans with chronic lung conditions (such as, asthma, COPD, cystic fibrosis, etc.), and humans with other comorbidities. In one aspect of this embodiment, the other co-morbidity is obesity, diabetes, and/or hypertension.

[0049] Pharmaceutical formulations can be adapted for administration via any desired suitable method, for example by oral (including buccal or sublingual), rectal, nasal, topical (including buccal, sublingual or transdermal), vaginal or parenteral (including subcutaneous, intramuscular, intravenous or intradermal) methods. Such formulations can be prepared using all processes known in the pharmaceutical art by, for example, combining the active ingredient with the excipient(s) or adjuvant(s).

[0050] Pharmaceutical formulations adapted for oral administration can be administered as separate units, such as, for example, capsules or tablets; powders or granules; solutions or suspensions in aqueous or non-aqueous liquids; edible foams or foam foods; or oil-in-water liquid emulsions or water-in-oil liquid emulsions.

[0051] Thus, for example, in the case of oral administration in the form of a tablet or capsule, the active-ingredient component can be combined with an oral, non-toxic and pharmaceutically acceptable inert excipient, such as, for example, ethanol, glycerol, water and the like. Powders are prepared by comminuting the compound to a suitable fine size and mixing it with a pharmaceutical excipient comminuted in a similar manner, such as, for example, an edible carbohydrate, such as, for example, starch or mannitol. A flavour, preservative, dispersant and dye may likewise be present.

[0052] Capsules are produced by preparing a powder mixture as described above and filling shaped gelatine shells therewith. Glidants and lubricants, such as, for example, highly disperse silicic acid, talc, magnesium stearate, calcium stearate or polyethylene glycol in solid form, can be added to the powder mixture before the filling operation. A disintegrant or solubiliser, such as, for example, agar-agar, calcium carbonate or sodium carbonate, may likewise be added in order to improve the availability of the medicament after the capsule has been taken.

[0053] In addition, if desired or necessary, suitable binders, lubricants and disintegrants as well as dyes can likewise be incorporated into the mixture. Suitable binders include starch, gelatine, natural sugars, such as, for example, glucose or beta-lactose, sweeteners made from maize, natural and synthetic rubber, such as, for example, acacia, tragacanth or sodium alginate, carboxymethylcellulose, polyethylene glycol, waxes, and the like. The lubricants used in these dosage forms include sodium oleate, sodium stearate, magnesium stearate, sodium benzoate, sodium acetate, sodium chloride and the like. The disintegrants include, without being restricted thereto, starch, methylcellulose, agar, bentonite, xanthan gum and the like. The tablets are formulated by, for example, preparing a powder mixture, granulating or dry-pressing the mixture, adding a lubricant and a disintegrant and pressing the entire mixture to give tablets. A powder mixture is prepared by mixing the compound comminuted in a suitable manner with a diluent or a base, as described above, and optionally with a binder, such as, for example, carboxymethylcellulose, an alginate, gelatine or polyvinyl-pyrrolidone, a dissolution retardant, such as, for example, paraffin, an ab-sorption accelerator, such as, for example, a quaternary salt, and/or an absorbant, such as, for example, bentonite, kaolin or dicalcium phosphate. The powder mixture can be granulated by wetting it with a binder, such as, for example, syrup, starch paste, acadia mucilage or solutions of cellulose or polymer materials and pressing it through a sieve. As an alternative to granulation, the powder mixture can be run through a tabletting machine, giving lumps of non-uniform shape, which are broken up to form granules. The granules can be lubricated by addition of stearic acid, a stearate salt, talc or mineral oil in order to prevent sticking to the tablet casting moulds. The lubricated mixture is then pressed to give tablets. The compounds according to the disclosure can also be combined with a free- flowing inert excipient and then pressed directly to give tablets without carrying out the granulation or dry-pressing steps. A transparent or opaque protective layer consisting of a shellac sealing layer, a layer of sugar or polymer material and a gloss layer of wax may be present. Dyes can be added to these coatings in order to be able to differentiate between different dosage units.

[0054] Oral liquids, such as, for example, solution, syrups and elixirs, can be pre-pared in the form of dosage units so that a given quantity comprises a pre-specified amount of the compound. Syrups can be prepared by dissolving the compound in an aqueous solution with a suitable flavour, while elixirs are prepared using a non-toxic alcoholic vehicle. Suspensions can be formulated by dispersion of the compound in a non-toxic vehicle. Solubilisers and emulsifiers, such as, for example, ethoxylated isostearyl alcohols and polyoxyethylene sorbitol ethers, preservatives, flavour additives, such as, for example, peppermint oil or natural sweeteners or saccharin, or other artificial sweeteners and the like, can likewise be added.

[0055] The dosage unit formulations for oral administration can, if desired, be encapsulated in microcapsules. The formulation can also be prepared in such a way that the release is extended or retarded, such as, for example, by coating or embedding of particulate material in polymers, wax and the like.

[0056] The compounds according to Formula (A) above, in particular compounds of the formula (1) to (31), and salts, solvates and physiologically functional derivatives thereof can also be administered in the form of lipo-some delivery systems, such as, for example, small unilamellar vesicles, large unilamellar vesicles and multilamellar vesicles. Liposomes can be formed from various phospholipids, such as, for example, cholesterol, stearylamine or phosphatidylcholines.

[0057] The compounds according to Formula (A) above, in particular compounds of the formula (1) to (31), and the salts, solvates, enantiomers, tautomer and stereoisomers thereof can also be delivered using monoclonal antibodies as individual carriers to which the compound molecules are coupled. The compounds can also be coupled to soluble polymers as targeted medicament carriers. Such polymers may encompass polyvinylpyrrolidone, pyran copolymer, polyhydroxypropylmethacrylamido-phenol, polyhydroxyethylaspartamidophenol or polyethylene oxide poly-lysine, substituted by palmitoyl radicals. The compounds may furthermore be coupled to a class of biodegradable polymers which are suitable for achieving controlled release of a medicament, for example polylactic acid, poly-epsilon-caprolactone, poly-hydroxybutyric acid, poly-orthoesters, poly-acetals, poly-dihydroxypyrans, polycyanoacrylates and crosslinked or amphipathic block copolymers of hydrogels.

[0058] Pharmaceutical formulations adapted for transdermal administration can be administered as independent plasters for extended, close contact with the epidermis of the recipient. Thus, for example, the active ingredient can be delivered from the plaster by iontophoresis, as described in general terms in Pharmaceutical Research, 3(6), 318 (1986).

[0059] Pharmaceutical compounds adapted for topical administration can be formulated as ointments, creams, suspensions, lotions, powders, solutions, pastes, gels, sprays, aerosols or oils.

[0060] For the treatment of the eye or other external tissue, for example mouth and skin, the formulations are preferably applied as topical ointment or cream. In the case of formulation to give an ointment, the active ingredient can be employed either with a paraffinic or a water- miscible cream base. Alternatively, the active ingredient can be formulated to give a cream with an oil-in-water cream base or a water-in-oil base.

[0061] Pharmaceutical formulations adapted for topical application to the eye include eye drops, in which the active ingredient is dissolved or suspended in a suitable carrier, in particular an aqueous solvent.

[0062] Pharmaceutical formulations adapted for topical application in the mouth encompass lozenges, pastilles and mouthwashes.

[0063] Pharmaceutical formulations adapted for rectal administration can be administered in the form of suppositories or enemas.

[0064] Pharmaceutical formulations adapted for nasal administration in which the carrier substance is a solid comprise a coarse powder having a particle size, for example, in the range 20-500 microns, which is administered in the manner in which snuff is taken, i.e. by rapid inhalation via the nasal pas-sages from a container containing the powder held close to the nose. Suitable formulations for administration as nasal spray or nose drops with a liquid as carrier substance encompass active-ingredient solutions in water or oil.

[0065] Pharmaceutical formulations adapted for administration by inhalation encompass finely particulate dusts or mists, which can be generated by various types of pressurised dispensers with aerosols, nebulisers or insufflators. [0066] Pharmaceutical formulations adapted for vaginal administration can be administered as pessaries, tampons, creams, gels, pastes, foams or spray formulations.

[0067] Pharmaceutical formulations adapted for parenteral administration include aqueous and non-aqueous sterile injection solutions comprising antioxidants, buffers, bacteriostatics and solutes, by means of which the formulation is rendered isotonic with the blood of the recipient to be treated; and aqueous and non-aqueous sterile suspensions, which may comprise sus-pension media and thickeners. The formulations can be administered in single-dose or multidose containers, for example sealed ampoules and vials, and stored in freeze-dried (lyophilised) state, so that only the addition of the sterile carrier liquid, for example water for injection purposes, immediately before use is necessary. Injection solutions and suspensions pre-pared in accordance with the recipe can be prepared from sterile powders, granules and tablets.

[0068] It goes without saying that, in addition to the above particularly mentioned constituents, the formulations may also comprise other agents usual in the art with respect to the particular type of formulation; thus, for example, formulations which are suitable for oral administration may comprise flavours.

[0069] A therapeutically effective amount of a Syk inhibitor such as a compound according to Formula (A) above, in particular a compound of Formula (1) to (31), depends on a number of factors, including, for example, the age and weight of the subject, the precise condition that requires treatment, and its severity, the nature of the formulation and the method of administration, and is ultimately determined by the treating doctor or vet. However, an effective amount of a compound according to the invention is generally in the range from 0.1 to 100 mg/kg of body weight of the recipient (mammal) per day and particularly typically in the range from 1 to 10 mg/kg of body weight per day. Thus, the actual amount per day for an adult mammal weighing 70 kg is usually between 70 and 700 mg, where this amount can be administered as a single dose per day or usually in a series of part-doses (such as, for example, two, three, four, five or six) per day, so that the total daily dose is the same. An effective amount of a salt or solvate or of a physiologically functional derivative thereof can be determined as the fraction of the effective amount of the compound according to the invention per se. It can be assumed that similar doses are suitable for the treatment of other conditions mentioned above. [0070] Compositions of the present invention are administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. Preferably, the compositions are administered orally. In one embodiment, the oral formulation of a compound of the invention is a tablet or capsule form. In another embodiment, the oral formulation is a solution or suspension which may be given to a subject in need thereof via mouth or nasogastric tube. Any oral formulations of the invention may be administered with or without food. In some embodiments, pharmaceutically acceptable compositions of this invention are administered without food. In other embodiments, pharmaceutically acceptable compositions of this invention are administered with food.

[0071] Pharmaceutically acceptable compositions of this invention are orally administered in any orally acceptable dosage form. Exemplary oral dosage forms are capsules, tablets, aqueous suspensions or solutions. In the case of tablets for oral use, carriers commonly used include lactose and corn starch. Lubricating agents, such as magnesium stearate, are also typically added. For oral administration in a capsule form, useful diluents include lactose and dried cornstarch. When aqueous suspensions are required for oral use, the active ingredient is combined with emulsifying and suspending agents. If desired, certain sweetening, flavoring or coloring agents are optionally also added.

[0072] The amount of compounds of the present invention that are optionally combined with the carrier materials to produce a composition in a single dosage form will vary depending upon the host treated, and the particular mode of administration. Preferably, provided compositions should be formulated so that a dosage of between 0.01 - 100 mg/kg body weight/day of the compound can be administered to a patient receiving these compositions.

[0073] The Syk inhibitor can be administered in the form of dosage units which comprise a predetermined amount of active ingredient per dosage unit. Such a unit can comprise, for example, 0.5 mg to 1 g, preferably 1 mg to 700 mg, particularly preferably 5 mg to 100 mg, of a Syk inhibitor according to the present disclosure, depending on the method of administration and the age, weight and condition of the patient, or a Syk inhibitor according to the present disclosure can be administered in the form of dosage units which comprise a predetermined amount of active ingredient per dosage unit. Preferred dosage unit formulations are those which comprise a daily dose or part-dose, as indicated above, or a corresponding fraction thereof of an active ingredient. Furthermore, pharmaceutical formulations of this type can be prepared using a process which is generally known in the pharmaceutical art. [0074] In one embodiment, the total amount of Syk inhibitor administered to the subject in need thereof is between about 5 mg to about 1000 mg per day.

[0075] In another embodiment, the Syk inhibitor is administered once a day. In another aspect of this embodiment, the Syk inhibitor is administered twice a day.

[0076] In any of the above embodiments, the Syk inhibitor is administered for a period of about 7 days to about 28 days (preferably, " about 7 days to about 28 days" means for at least 7 ± 0.5 days, but not more than 21 days ± 0.5 days). In one aspect of any of the above embodiments, the Syk inhibitor is administered for about 14 days (preferably, "about 14 days" means for 14 days ± 0.5 days).

[0077] In one embodiment of the invention, the subject is suffering from COVID-19 pneumonia. In one embodiment of this invention, the subject is suffering from one or more symptoms selected from chest congestion, cough, blood oxygen saturation (SpO2) levels below 94%, shortness of breath, difficulty breathing, fever, chills, repeated shaking with chills, muscle pain and/or weakness, headache, sore throat and/or new loss of taste or smell.

[0078] In one embodiment, the subject is suffering from a hyperinflammatory host immune response to a SARS-CoV-2 infection. In one embodiment, the subject is not suffering from a hyperinflammatory host immune response to a SARS-CoV-2 infection. In one aspect of this embodiment, the hyperinflammatory host immune response is associated with one or more clinical indications selected from 1) reduced levels of lymphocytes, especially natural killer (NK) cells in peripheral blood; 2) high levels of inflammatory parameters (e.g., C reactive protein [CRP], ferritin, d-dimer), and pro-inflammatory cytokines (e.g., IL-6, TNF-alpha, IL- 8, and/or IL-lbeta; 3) a deteriorating immune system demonstrated by lymphocytopenia and/or atrophy of the spleen and lymph nodes, along with reduced lymphocytes in lymphoid organs; 4) dysfunction of the lung physiology represented by lung lesions infiltrated with monocytes, macrophages, and/or neutrophils, but minimal lymphocytes infiltration resulting in decreased oxygenation of the blood; 5) acute respiratory distress syndrome (ARDS); 6) vasculitis; 7) encephalitis, Guillain-Barre syndrome, and other neurologic disorders; 8) kidney dysfunction and kidney failure; 9) hypercoagulability such as arterial thromboses; and 10) or any combination of above resulting in end-organ damage and death.

[0079] In one embodiment, the subject with COVID-19 is a pediatric patient suffering from vasculitis, including Kawasaki disease (i.e., Kawasaki syndrome) and Kawasaki-like disease. [0080] In one embodiment of the invention, the subject is being treated inpatient in a hospital setting. In another embodiment, the subject is being treated in an outpatient setting. In one aspect of the preceding embodiments, the subject may continue administration of the Syk inhibitor after being transitioned from being treated from an inpatient hospital setting to an outpatient setting.

[0081] In one embodiment, the administration of the Syk inhibitor results in one or more clinical benefit. In one aspect of this embodiment, the one or more clinical benefit is selected from the group consisting of: reduction of duration of a hospital stay, reduction of the duration of time in the Intensive Care Unit (ICU), reduction in the likelihood of the subject being admitted to an ICU, reduction in the rate of mortality, reduction in the likelihood of kidney failure requiring dialysis, reduction in the likelihood of being put on non-invasive or invasive mechanical ventilation, reduction of the time to recovery, reduction in the likelihood that supplemental oxygen will be needed, improvement or normalization in the peripheral capillary oxygen saturation (SpCh levels) without mechanical intervention, reduction of severity of the pneumonia as determined by chest imaging (e.g., CT or chest X ray), reduction in the cytokine production, reduction of the severity of acute respiratory distress syndrome (ARDS), reduction in the likelihood of developing ARDS, clinical resolution of the COVID-19 pneumonia, improvement of the PaO2/FiO2 ratio, and reduction of the inflammatory response in the subject.

[0082] In another embodiment, the one or more clinical benefits include the improvement or normalization in the peripheral capillary oxygen saturation (SpO2 levels) in the subject without mechanical ventilation or extracorporeal membrane oxygenation.

[0083] In one embodiment, the one or more clinical benefits include the reduction of the inflammatory response of the subject. In one aspect of this embodiment, the reduction of the inflammatory response in the subject results in the reduction of proinflammatory cytokine release driven by NF-kappa-B, IL-lb, IL-6, IL-8, IL-12, IL-18, IL-23, or IL-27, alone or in combination with inhibition of cytokine release driven by IRF3/7, such as type I IFNs, including IFN-alpha and/or IFN-beta. In one aspect of this embodiment, the one or more clinical benefits includes the avoidance of a severe cytokine storm in the subject.

[0084] In a further embodiment, the one of more clinical benefits is reduction in the likelihood of being hospitalized, reduction in the likelihood of ICU admission, reduction in the likelihood of being intubated (invasive mechanical ventilation), reduction in the likelihood that supplemental oxygen will be needed, reduction in the length of hospital stay, reduction in the likelihood of mortality, and/or a reduction in likelihood of relapse, including the likelihood of rehospitalization.

[0085] The invention also provides a method of treating a viral infection in a subject in need thereof comprising administering an effective amount of a compound of the invention to the subject. An amount effective to treat or inhibit a viral infection is an amount that will cause a reduction in one or more of the manifestations of viral infection, such as viral lesions, viral load, rate of virus production, and mortality as compared to untreated control subjects. In one embodiment, said treatment is an anti-viral treatment.

[0086] One aspect of the invention is a method of treating a coronavirus infection in a subject in need thereof, comprising administering an effective amount of a Syk inhibitor, or a pharmaceutically acceptable salt thereof, to the subject. In one embodiment, said treatment is an anti-viral treatment. In one embodiment, the subject is infected with SARS-CoV-2. In another embodiment, the administration of the Syk inhibitor results in the reduction of the viral load in the subject. In another embodiment, the administration of the Syk inhibitor results in the reduction of virus-infected cells in the subject. In another embodiment, the administration of the Syk inhibitor results in the reduction of virus-infected cells in the subject during the first 10 days after infection. In another embodiment, the administration of the Syk inhibitor results in the reduction of virus-infected cells in the subject during the first 7 days after infection. In another embodiment, the administration of the Syk inhibitor results in the reduction of virus- infected cells in the subject during the time span of day 5 to 10 after infection. In another embodiment, the administration of the Syk inhibitor results in the reduction of virus-infected cells in the subject during the time span of day 3 to 7 after infection. In another embodiment, the administration of the Syk inhibitor results in the reduction of virus-infected cells in the subject during the time span of day 5 to 7 after infection.

[0087] In one embodiment, the Syk inhibitor is administered prior to COVID-19 pneumonia development. In one embodiment, the Syk inhibitor is administered prior to the subject developing a cytokine storm. In another embodiment, the subject has a mild to moderate SARS-CoV-2 infection. In a further embodiment, the subject is asymptomatic at the start of the administration regimen. In another embodiment, the subject has had known contact with a patient who has been diagnosed with a SARS-CoV-2 infection. In an additional embodiment, the subject begins administration of the Syk inhibitor prior to being formally diagnosed with COVID-19. In one embodiment, said Syk inhibitor is administered during the first 10 days after infection with SARS-CoV-2. In one embodiment, said Syk inhibitor is administered during the first 7 days after infection with SARS-CoV-2. In another aspect of this embodiment, said Syk inhibitor is administered during the time span of day 5 to 10 after infection. In another aspect of this embodiment, said Syk inhibitor is administered during the time span of day 3 to 7 after infection. In another aspect of this embodiment, said Syk inhibitor is administered during the time span of day 5 to 7 after infection.

[0088] One embodiment is a method of treating a subject with COVID-19 comprising administration of an effective amount of a Syk inhibitor to the subject. In one aspect of this embodiment, the subject has been previously vaccinated with a SARS-CoV-2 vaccine and develops vaccine-related exacerbation of infection, for example, an antibody-dependent enhancement or related antibody-mediated mechanisms of vaccine/antibody-related exacerbation.

[0089] In any of the above aspects and embodiments, the administration of the Syk inhibitor results in one or more clinical benefits to the subject. In one aspect of this embodiment, the one or more clinical benefits is shortening the duration of infection, reduction of the likelihood of hospitalization, reduction in the likelihood of mortality, reduction in the likelihood of ICU admission, reduction in the likelihood of being placed on mechanical ventilation, reduction in the likelihood that supplemental oxygen will be needed, and/or reduction in the length of hospital stay. In another embodiment, the one or more clinical benefits is avoidance of a significant proinflammatory response. In a further aspect of this embodiment, the one or more clinical benefit is the failure of the subject to develop significant symptoms of COVID-19.

[0090] The compounds of the invention can be administered before or following an onset of SARS-CoV-2 infection, or after acute infection has been diagnosed in a subject. The aforementioned compounds and medical products of the inventive use are particularly used for the therapeutic treatment. A therapeutically relevant effect relieves to some extent one or more symptoms of a disorder, or returns to normality, either partially or completely, one or more physiological or biochemical parameters associated with or causative of a disease or pathological condition. Monitoring is considered as a kind of treatment provided that the compounds are administered in distinct intervals, e.g. in order to boost the response and eradicate the pathogens and/or symptoms of the disease. The methods of the invention can also be used to reduce the likelihood of developing a disorder or even prevent the initiation of disorders associated with COVID-19 in advance of the manifestation of mild to moderate disease, or to treat the arising and continuing symptoms of an acute infection. [0091] Treatment of mild to moderate CO VID-19 is typically done in an outpatient setting. Treatment of moderate to severe COVID-19 is typically done inpatient in a hospital setting. Additionally, treatment can continue in an outpatient setting after a subject has been discharged from the hospital.

[0092] The invention furthermore relates to a medicament comprising at least one compound according to the invention or a pharmaceutically acceptable salt thereof.

[0093] A “medicament” in the meaning of the invention is any agent in the field of medicine, which comprises one or more compounds of the invention or preparations thereof (e.g. a pharmaceutical composition or pharmaceutical formulation) and can be used in prophylaxis, therapy, follow-up or aftercare of patients who suffer from clinical symptoms and/or known exposure to COVID-19.

Combination Treatment

[0094] In various embodiments, the active ingredient may be administered alone or in combination with one or more additional therapeutic agents. A synergistic or augmented effect may be achieved by using more than one compound in the pharmaceutical composition. The active ingredients can be used either simultaneously or sequentially.

[0095] In one embodiment, the Syk inhibitor is administered in combination with one or more additional therapeutic agents. In one aspect of this embodiment, the one or more additional therapeutic agents is selected from anti-inflammatories, antibiotics, anti-coagulants, antiparasitic agent, antiplatelet agents and dual antiplatelet therapy, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, beta-blockers, statins and other combination cholesterol lowering agents, specific cytokine inhibitors, complement inhibitors, anti-VEGF treatments, JAK inhibitors, immunomodulators, anti-inflammasome therapies, sphingosine-1 phosphate receptors binders, N-methyl-d-aspartate (NDMA) receptor glutamate receptor antagonists, corticosteroids, Granulocyte-macrophage colony-stimulating factor (GM-CSF), anti-GM-CSF, interferons, angiotensin receptor-neprilysin inhibitors, calcium channel blockers, vasodilators, diuretics, muscle relaxants, and antiviral medications.

[0096] In one embodiment, the Syk inhibitor is administered in combination with an antiviral agent. In one aspect of this embodiment, the antiviral agent is remdesivir. In another aspect of this embodiment, the antiviral agent is lopinavir-ritonavir, alone or in combination with ribavirin and interferon-beta. [0097] In one embodiment, the Syk inhibitor is administered in combination with a broadspectrum antibiotic.

[0098] In one embodiment, the Syk inhibitor is administered in combination with chloroquine or hydroxychloroquine. In one aspect of this embodiment, the Syk inhibitor is further combined with azithromycin.

[0099] In one embodiment, the Syk inhibitor is administered in combination with interferon- 1 -beta (Rebif®).

[00100] In one embodiment, the Syk inhibitor is administered in combination with one or more additional therapeutic agents selected from hydroxychloroquine, chloroquine, ivermectin, tranexamic acid, nafamostat, virazole, ribavirin, lopinavir/ritonavir, favipiravir, arbidol, leronlimab, interferon beta-la, interferon beta-lb, beta-interferon, azithromycin, nitrazoxamide, lovastatin, clazakizumab, adalimumab, etanercept, golimumab, infliximab, sarilumab, tocilizumab, anakinra, emapalumab, pirfenidone, belimumab, rituximab, ocrelizumab, anifrolumab, ravulizumab-cwvz, eculizumab, bevacizumab, heparin, enoxaparin, apremilast, coumadin, baricitinib, ruxolitinib, dapagliflozin, methotrexate, leflunomide, azathioprine, sulfasalazine, mycophenolate mofetil, colchicine, fmgolimod, ifenprodil, prednisone, cortisol, dexamethasone, methylprednisolone, melatonin, otilimab, ATR-002, APN-01, camostat mesylate, brilacidin, IFX-1, PAX-1-001, BXT-25, NP-120, intravenous immunoglobulin (IVIG), and solnatide.

[00101] In one embodiment, the Syk inhibitor is administered in combination with one or more anti-inflammatory agent. In one aspect of this embodiment, the anti-inflammatory agent is selected from corticosteroids, steroids, COX-2 inhibitors, and non-steroidal antiinflammatory drugs (NSAID). In one aspect of this embodiment, the anti-inflammatory agent is diclofenac, etodolac, fenoprofen, flurbirprofen, ibuprofen, indomethacin, meclofenamate, mefenamic acid, meloxicam, nabumetone, naproxen, oxaprozin, piroxicam, sulindac, tolmetin, celecoxib, prednisone, hydrocortisone, fludocortisone, betham ethasone, prednisolone, triamcinolone, methylprednisone, dexamethasone, fluticasone, and budesonide (alone or in combination with formoterol, salmeterol, or vilanterol).

[00102] In one embodiment, the Syk inhibitor is administered in combination with one or more immune modulators. In one aspect of this embodiment the immune modulator is a calcineurin inhibitor, antimetabolite, or alkylating agent. In another aspect of this embodiment, the immune modulator is selected from azathioprine, mycophenolate mofetil, methotrexate, dapson, cyclosporine, cyclophosphamide, and the like.

[00103] In one embodiment, the Syk inhibitor is administered in combination with one or more antibiotics. In one aspect of this embodiment, the antibiotic is a broad-spectrum antibiotic. In another aspect of this embodiment, the antibiotic is a pencillin, anti- straphylococcal penicillin, cephalosporin, aminopenicillin (commonly administered with a beta lactamase inhibitor), monobactam, quinoline, aminoglycoside, lincosamide, macrolide, tetracycline, glycopeptide, antimetabolite or nitroimidazole. In a further aspect of this embodiment, the antibiotic is selected from penicillin G, oxacillin, amoxicillin, cefazolin, cephalexin, cephotetan, cefoxitin, ceftriazone, augmentin, amoxicillin, ampicillin (plus sulbactam), piperacillin (plus tazobactam), ertapenem, ciprofloxacin, imipenem, meropenem, levofloxacin, moxifloxacin, amikacin, clindamycin, azithromycin, doxycycline, vancomycin, Bactrim, and metronidazole.

[00104] In one embodiment, the Syk inhibitor is administered in combination with one or more anti-coagulants. In one aspect of this embodiment, the anti -coagulant is selected from apixaban, dabigatran, edoxaban, heparin, rivaroxaban, and warfarin.

[00105] In one embodiment, the Syk inhibitor is administered in combination with one or more antiplatelet agents and/or dual antiplatelet therapy. In one aspect of this embodiment, the antiplatelet agent and/or dual antiplatelet therapy is selected from aspirin, clopidogrel, dipyridamole, prasugrel, and ticagrelor.

[00106] In one embodiment, the Syk inhibitor is administered in combination with one or more ACE inhibitors. In one aspect of this embodiment, the ACE inhibitor is selected from benazepril, captopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril and trandolapril.

[00107] In one embodiment, the Syk inhibitor is administered in combination with one or more angiotensin II receptor blockers. In one aspect of this embodiment, the angiotensin II receptor blocker is selected from azilsartan, candesartan, eprosartan, irbesartan, losartan, olmesartan, telmisartan, and valsartan.

[00108] In one embodiment, the Syk inhibitor is administered in combination with one or more beta-blockers. In one aspect of this embodiment, the beta-blocker is selected from acebutolol, atenolol, betaxolol, bisoprolol/hydrochlorothiazide, bisoprolol, metoprolol, nadolol, propranolol, and sotalol. [00109] In another embodiment, the Syk inhibitor is administered in combination with one or more alpha and beta-blocker. In one aspect of this embodiment, the alpha and beta-blocker is carvedilol or labetalol hydrochloride.

[00110] In one embodiment, the Syk inhibitor is administered in combination with one or more interferons.

[00111] In one embodiment, the Syk inhibitor is administered in combination with one or more angiotensin receptor-neprilysin inhibitors. In one aspect of this embodiment, the angiotensin receptor-neprilysin inhibitor is sacubitril/valsartan.

[00112] In one embodiment, the Syk inhibitor is administered in combination with one or more calcium channel blockers. In one aspect of this embodiment, the calcium channel blocker is selected from amlodipine, diltiazem, felodipine, nifedipine, nimodipine, nisoldipine, and verapamil.

[00113] In one embodiment, the Syk inhibitor is administered in combination with one or more vasodilators. In one aspect of this embodiment, the one or more vasodilator is selected from isosorbide dinitrate, isosorbide mononitrate, nitroglycerin, and minoxidil.

[00114] In one embodiment, the Syk inhibitor is administered in combination with one or more diuretics. In one aspect of this embodiment, the one or more diuretics is selected from acetazolamide, amiloride, bumetanide, chlorothiazide, chlorthalidone, furosemide, hydrochlorothiazide, indapamide, metalazone, spironolactone, and torsemide.

[00115] In one embodiment, the Syk inhibitor is administered in combination with one or more muscle relaxants. In one aspect of this embodiment, the muscle relaxant is an antispasmodic or antispastic. In another aspect of this embodiment, the one or more muscle relaxants is selected from casisoprodol, chlorzoxazone, cyclobenzaprine, metaxalone, methocarbamol, orphenadrine, tizanidine, baclofen, dantrolene, and diazepam.

[00116] In one embodiment, the Syk inhibitor is administered in combination with one or more antiviral medications. In one aspect of this embodiment, the antiviral medication is remdesivir.

[00117] In one embodiment, the Syk inhibitor is administered in combination with one or more additional therapeutic agents selected from antiparasitic drugs (including, but not limited to, hydroxychloroquine, chloroquine, ivermectin), antivirals (including, but not limited to, tranexamic acid, nafamostat, virazole [ribavirin], lopinavir/ritonavir, favipiravir, leronlimab, interferon beta-la, interferon beta-lb, beta-interferon), antibiotics with intracellular activities (including, but not limited to azithromycin, nitrazoxamide), statins and other combination cholesterol lowering and anti-inflammatory drugs (including, but not limited to, lovastatin), specific cytokine inhibitors (including, but not limited to, clazakizumab, adalimumab, etanercept, golimumab, infliximab, sarilumab, tocilizumab, anakinra, emapalumab, pirfenidone), complement inhibitors (including, but not limited to, ravulizumab-cwvz, eculizumab), anti-VEGF treatments (including, but not limited to, bevacizumab), anticoagulants (including, but not limited to, heparin, enoxaparin, apremilast, coumadin), JAK inhibitors (including, but not limited to, baricitinib, ruxolitinib, dapagliflozin), anti- inflammasome therapies (including, but not limited to, colchicine), sphingosine- 1 phosphate receptors binders (including, but not limited to, fingolimod), N-methyl-d-aspartate (NDMA) receptor glutamate receptor antagonists (including, but not limited to, ifenprodil), corticosteroids (including, but not limited to, prednisone, cortisol, dexamethasone, methylprednisolone), GM-CSF, anti-GM-CSF (otilimab), ATR-002, APN-01, camostat mesylate, arbidol, brilacidin, IFX-1, PAX-1-001, BXT-25, NP-120, intravenous immunoglobulin (IVIG), and solnatide.

[00118] In some embodiments, the combination of a Syk inhibitor with one or more additional therapeutic agents reduces the effective amount (including, but not limited to, dosage volume, dosage concentration, and/or total drug dose administered) of the Syk inhibitor and/or the one or more additional therapeutic agents administered to achieve the same result as compared to the effective amount administered when the Syk inhibitor or the additional therapeutic agent is administered alone. In some embodiments, the combination of a Syk inhibitor with the additional therapeutic agent reduces the total duration of treatment compared to administration of the additional therapeutic agent alone. In some embodiments, the combination of a Syk inhibitor with the additional therapeutic agent reduces the side effects associated with administration of the additional therapeutic agent alone. In some embodiments, the combination of an effective amount of the Syk inhibitor with the additional therapeutic agent is more efficacious compared to an effective amount of the Syk inhibitor or the additional therapeutic agent alone. In one embodiment, the combination of an effective amount of the Syk inhibitor with the one or more additional therapeutic agent results in one or more additional clinical benefits than administration of either agent alone.

[00119] As used herein, the terms “treatment,” “treat,” and “treating” refer to reversing, alleviating, delaying the onset of, or inhibiting the progress of a viral infection, or one or more symptoms thereof, as described herein. In some embodiments, treatment is administered after one or more symptoms have developed. In other embodiments, treatment is administered in the absence of symptoms. For example, treatment is administered to a susceptible individual prior to the onset of symptoms (e.g., in light of a known exposure to an infected person and/or in light of comorbidities which are predictors for severe disease, or other susceptibility factors).

Also disclosed with regard to the above-described subject matter is the following:

[1] A method of treating a coronavirus infection in a subject in need thereof, comprising administering an effective amount of a Syk inhibitor, or a pharmaceutically acceptable salt or solvate or hydrate thereof, to the subject.

[2] A Syk inhibitor or a pharmaceutically acceptable salt or solvate or hydrate thereof for use in the treatment of a coronavirus infection.

[3] Use of a Syk inhibitor or a pharmaceutically acceptable salt or solvate or hydrate thereof in the manufacture of a medicament for the treatment of a coronavirus infection.

[4] The method according to [1] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to [2] or the use according to [3], wherein the coronavirus causes a SARS or MERS infection.

[5] The method according to any one of [1] or [4] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] or the use according to any one of [3] to [4], wherein the coronavirus causes a SARS-CoV-1 or SARS-CoV-2 or MERS-CoV infection.

[6] The method according to any one of [1] or [4] to [5] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [5] or the use according to any one of [3] to [5], wherein the coronavirus is SARS-CoV-2. [7] The method according to any one of [1] or [4] to [6] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [6] or the use according to any one of [3] to [6], wherein the Syk inhibitor is a pyridopyrimidine.

[8] The method according to any one of [1] or [4] to [7] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [7] or the use according to any one of [3] to [7], wherein the Syk inhibitor is a compound according to Formula (A)

Formula (A) wherein

T is selected from the group consisting of H, NH2 and CH3, wherein 1 to

3 H atoms of said CH3 may be replaced by F;

I is selected from the group consisting of P¹, P² and P³;

Vi is selected from the group consisting of NH and O;

V2 is selected from the group consisting of NH2, OH, NHR^3a, N(R^3a)2 and

OR^3a;

[9] The method according to any one of [1] or [4] to [8] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [8] or the use according to any one of [3] to [8], wherein the Syk inhibitor is a compound according to Formula (A)

Formula (A) wherein

A is N;

T is selected from the group consisting of H, NH2 and CHF2;

I is selected from the group consisting of P¹, P² and P³;

P¹ is cyclohexyl which is unsubstituted or mono-, di-, tri- or tetrasubstituted by Hal, CN, OH, NH2, NHR^3a, N(R^3a)2, OR^3a and/or R^3a; P² is selected from the group consisting of phenyl and 4-pyrazolyl, wherein said phenyl or 4-pyrazolyl is unsubstituted or mono-, di-, trior tetrasubstituted by Hal, Het, CN, OH, NH₂, NHR^3a, N(R^3a)₂, OR^3a and/or R^3a;

P³ is

Vi is NH;

V₂ is selected from the group consisting of NH₂ and OH;

[10] The method according to any one of [1] or [4] to [9] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [9] or the use according to any one of [3] to [9], wherein the Syk inhibitor is a compound according to Formula (A)

Formula (A) wherein A is N;

T is selected from the group consisting of H, NH2 and CHF2;

I is selected from the group consisting of P¹, P² and P³;

P³ is

Vi is NH;

V2 is selected from the group consisting of NH2 and OH;

[11] The method according to any one of [1] or [4] to [10] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [10] or the use according to any one of [3] to [10], wherein the Syk inhibitor is a compound according to Formula (A)

Formula (A) wherein

A is N;

T is selected from the group consisting of H, NH2 and CHF2;

I is selected from the group consisting of P² and P³;

U is a group defined by formula xa), formula xb), formula xc) or formula xd), wherein said group defined by formula xa), formula xb), formula xc) or formula xd) is unsubstituted or mono-, di- or tri substituted by Hal, CN, OR^3a, N(R^3a)2, NHR^3a, and/or R^3a, wherein 1, 2 or 3 of the cyclic CH2 groups may be independently replaced by C=O, O, S, NR^3a, SO and/or SO2;

P³ is

Vi is NH;

V₂ is selected from the group consisting of NH₂ and OH;

Het is a 5-membered aromatic heterocycle wherein the heterocyclic system contains 1, 2 or 3 N, O and/or S atoms. [12] The method according to any one of [1] or [4] to [11] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [11] or the use according to any one of [3] to [11], wherein the Syk inhibitor is a compound selected from the Table of Compounds below:

Table of Compounds:

SUBSTITUTE SHEET (RULE 26)

SUBSTITUTE SHEET (RULE 26)

SUBSTITUTE SHEET (RULE 26)

[13] The method according to any one of [1] or [4] to [12] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [12] or the use according to any one of [3] to [12], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 and 31 (as defined in the Table of Compounds).

[14] The method according to any one of [1] or [4] to [13] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [13] or the use according to any one of [3] to [13], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 19, 20, 21, 23, 24, 25, 26, 27, 28, 29, 30 and 31 (as defined in the Table of Compounds).

[15] The method according to any one of [1] or [4] to [14] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [14] or the use according to any one of [3] to [14], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 1, 2, 3, 7, 10, 11, 12, 14, 15, 16, 17, 19, 21, 25, 27, 28, 29 and 31 (as defined in the Table of Compounds).

[16] The method according to any one of [1] or [4] to [15] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [15] or the use according to any one of [3] to [15], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 2, 3, 10, 11, 12, 15, 16, 17 and 28 (as defined in the Table of Compounds).

[17] The method according to any one of [1] or [4] to [16] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [16] or the use according to any one of [3] to [16], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 2, 4, 5, 11, 12,

14, 24, 25, 26 and 31 (as defined in the Table of Compounds).

[18] The method according to any one of [1] or [4] to [17] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [17] or the use according to any one of [3] to [17], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 2, 11 and 12 (as defined in the Table of Compounds).

[19] The method according to any one of [1] or [4] to [18] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [18] or the use according to any one of [3] to [18], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 1, 3, 10, 13,

15, 16, 17, 22, 27 and 28 (as defined in the Table of Compounds).

[20] The method according to any one of [1] or [4] to [19] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [19] or the use according to any one of [3] to [19], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 3, 10, 13, 16 and 17 (as defined in the Table of Compounds).

[21] The method according to any one of [1] or [4] to [20] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [20] or the use according to any one of [3] to [20], wherein the Syk inhibitor is Compound 13 (as defined in the Table of Compounds). [22] The method according to any one of [1] or [4] to [21] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [21] or the use according to any one of [3] to [21], wherein the Syk inhibitor is a compound selected from the group consisting of Compound 1 and 3 (as defined in the Table of Compounds).

[23] The method according to any one of [1] or [4] to [22] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [22] or the use according to any one of [3] to [22], wherein the Syk inhibitor is Compound 3 (as defined in the Table of Compounds).

[24] The method according to any one of [1] or [4] to [7] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [7] or the use according to any one of [3] to [7], wherein the Syk inhibitor is the compound according to Formula (1):

or a pharmaceutically acceptable salt and/or solvate or hydrate thereof.

[25] The method according to any one of [1] or [4] to [7] or [24] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [7] or [24] or the use according to any one of [3 ] to [7] or [24], wherein the Syk inhibitor is 3-[2-((lR,2S)-2-amino-cyclohexylamino)-5-difluoromethyl- pyrido[4,3-d]pyrimidin-8-yl]-lH-indole-6-carbonitrile. [26] The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [25] or the use according to any one of [3] to [25], wherein said use involves administration of said Syk inhibitor to a subject in need thereof.

[27] The method according to any one of [1] or [4] to [25] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to [26] or the use according to [26], wherein the administration of the Syk inhibitor results in the reduction of the viral load in the subject.

[28] The method according to any one of [1] or [4] to [25] or [27] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [27] or the use according to any one of [26] to [27], wherein administration of the Syk inhibitor reduces the viral load in cells infected with coronavirus.

[29] The method according to any one of [1] or [4] to [25] or [27] to [28] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [28] or the use according to any one of [26] to [28], wherein administration of the Syk inhibitor reduces the number of cells infected with coronavirus.

[30] The method according to any one of [1] or [4] to [25] or [27] to [29] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [29] or the use according to any one of [26] to [29], wherein the Syk inhibitor is administered prior to COVID-19 pneumonia development.

[31] The method according to any one of [1] or [4] to [25] or [27] to [30] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [30] or the use according to any one of [26] to [30], wherein the Syk inhibitor is administered prior to the subject developing a cytokine storm.

[32] The method according to any one of [1] or [4] to [25] or [27] to [31] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [31] or the use according to any one of [26] to [31], wherein said Syk inhibitor is administered during the first 10 days after infection with SARS-CoV-2. [33] The method according to any one of [1] or [4] to [25] or [27] to [32] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [32] or the use according to any one of [26] to [32], wherein said Syk inhibitor is administered during the time span of day 5 to 10 after infection with SARS-CoV-2.

[34] The method according to any one of [1] or [4] to [25] or [27] to [31] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [31] or the use according to any one of [26] to [31], wherein said Syk inhibitor is administered during the first 7 days after infection with SARS-CoV-2.

[35] The method according to any one of [1] or [4] to [25] or [27] to [34] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [34] or the use according to any one of [26] to [34], wherein said Syk inhibitor is administered during the time span of day 3 to 7 after infection with SARS-CoV-2.

[36] The method according to any one of [1] or [4] to [25] or [27] to [35] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [35] or the use according to any one of [26] to [35], wherein said Syk inhibitor is administered during the time span of day 5 to 7 after infection with SARS-CoV-2.

[37] The method according to any one of [1] or [4] to [25] or [27] to [36] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [36] or the use according to any one of [26] to [36], wherein the subject has a mild to moderate SARS-CoV-2 infection.

[38] The method according to any one of [1] or [4] to [25] or [27] to [37] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [37] or the use according to any one of [26] to [37], wherein the subject has been previously vaccinated with a SARS-CoV-2 vaccine and develops vaccine-related exacerbation of infection, for example, an antibody-dependent enhancement or related antibody-mediated mechanisms of vaccine/antibody-related exacerbation.

[39] The method according to any one of [1] or [4] to [25] or [27] to [38] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [38] or the use according to any one of [26] to [38], wherein the subject is asymptomatic at the start of the treatment.

[40] The method according to any one of [1] or [4] to [25] or [27] to [39] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [39] or the use according to any one of [26] to [39], wherein the subject has had known contact with a patient who has been diagnosed with a SARS-CoV- 2 infection.

[41] The method according to any one of [1] or [4] to [25] or [27] to [40] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [40] or the use according to any one of [26] to [40], wherein the subject begins administration of the Syk inhibitor prior to being formally diagnosed with SARS-CoV-2 infection.

[42] The method according to any one of [1] or [4] to [25] or [27] to [41] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [41] or the use according to any one of [26] to [41], wherein the administration of the Syk inhibitor results in one or more clinical benefits.

[43] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to [42], wherein the one or more clinical benefits is selected from: shortening the duration of infection, reduction of the likelihood of hospitalization, reduction in the likelihood of mortality, reduction in the likelihood of ICU admission, reduction in the likelihood of being placed on mechanical ventilation, reduction in the likelihood that supplemental oxygen will be needed, and/or reduction in the length of hospital stay. [44] The method according to any one of [1] or [4] to [25] or [27] to [43] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [26] to [43] or the use according to any one of [26] to [43], wherein the subject is undergoing outpatient treatment.

[45] The method according to any one of [1] or [4] to [25] or [27] to [44] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [44] or the use according to any one of [3] to [44], further comprising administration of one or more additional therapeutic agent.

[46] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to [45], wherein the one or more additional therapeutic agents is selected from anti-inflammatories, antibiotics, anti-coagulants, antiparasitic agent, antiplatelet agents and dual antiplatelet therapy, angiotensin converting enzyme (ACE) inhibitors, angiotensin II receptor blockers, beta-blockers, statins and other combination cholesterol lowering agents, specific cytokine inhibitors, complement inhibitors, anti-VEGF treatments, JAK inhibitors, immunomodulators, anti- inflammasome therapies, sphingosine- 1 phosphate receptors binders, N-methyl-d- aspartate (NDMA) receptor glutamate receptor antagonists, corticosteroids, Granulocytemacrophage colony-stimulating factor (GM-CSF), anti-GM-CSF, interferons, angiotensin receptor-neprilysin inhibitors, calcium channel blockers, vasodilators, diuretics, muscle relaxants, and antiviral medications.

[47] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to any one of [45] to [46], wherein the one or more additional therapeutic agents is an antiviral medication.

[48] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to any one of [45] to [47], wherein the one or more additional therapeutic agents is remdesivir.

[49] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to any one of [45] to [47], wherein the one or more additional therapeutic agents is lopinavir-ritonavir. [50] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to any one of [45] to [49], wherein the one or more additional therapeutic agents further includes ribavirin and interferon-beta.

[51] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to any one of [45] to [47] or [50], wherein the one or more additional therapeutic agents is chloroquine or hydroxychloroquine.

[52] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to any one of [45] to [51], wherein the one or more additional therapeutic agents further includes azithromycin.

[53] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to any one of [45] to [47] or [50] or [52], wherein the one or more additional therapeutic agents is interferon- 1 -beta (Rebif®).

[54] The method or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use or the use according to any one of [45] to [47] or [50] or [52], wherein the one or more additional therapeutic agent is selected from hydroxychloroquine, chloroquine, ivermectin, tranexamic acid, nafamostat, virazole [ribavirin], lopinavir/ritonavir, favipiravir, leronlimab, interferon beta- la, interferon beta-lb, beta-interferon, azithromycin, nitrazoxamide, lovastatin, clazakizumab, adalimumab, etanercept, golimumab, infliximab, sarilumab, tocilizumab, anakinra, emapalumab, pirfenidone, ravulizumab-cwvz, eculizumab, bevacizumab, heparin, enoxaparin, apremilast, coumadin, baricitinib, ruxolitinib, dapagliflozin, colchicine, fmgolimod, ifenprodil, prednisone, cortisol, dexamethasone, methylprednisolone, GM- CSF, otilimab, ATR-002, APN-01, camostat mesylate, arbidol, brilacidin, IFX-1, PAX- 1-001, BXT-25, NP-120, intravenous immunoglobulin (IVIG), and solnatide.

[55] The method according to any one of [1] or [4] to [25] or [27] to [54] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [54] or the use according to any one of [3] to [54], wherein the Syk inhibitor is administered daily. [56] The method according to any one of [1] or [4] to [25] or [27] to [55] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [55] or the use according to any one of [3] to [55], wherein the total amount of Syk inhibitor administered is between about 10 mg and about 1000 mg per day.

[57] The method according to any one of [1] or [4] to [25] or [27] to [56] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [56] or the use according to any one of [3] to [56], wherein the Syk inhibitor is administered for about 7 days to about 21 days.

[58] The method according to any one of [1] or [4] to [25] or [27] to [57] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [57] or the use according to any one of [3] to [57], wherein the Syk inhibitor is administered by oral administration.

[59] The method according to any one of [1] or [4] to [58] or the Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of [2] or [4] to [58] or the use according to any one of [3] to [58], wherein the Syk inhibitor is not fostamatinib.

EXEMPLIFICATION

[00120] As described in the Examples below, in certain exemplary embodiments, compounds are prepared according to the following procedures.

Example 1: Synthesis of Compound 1

[00121] Compound 1, a Syk inhibitor of the pyridopyrimidine class, is prepared in accordance with the procedure disclosed in WO 2014/023385 Al (Example 87), as illustrated by the following reaction scheme:

1. 5-methyl-2-methylsulfanyl-pyrido[4,3-d1pyrimidine

[00122] 5 -Chloro-2-methylsulfanyl-pyrido[4,3-d]pyrimidine (500.000 mg; 2.135 mmol;

100.00 mol %), trimethylboroxine, 50 wt % solution in THF (536.130 mg; 2.135 mmol; 100.00 mol %), 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (90.375 mg; 0.214 mmol; 10.00 mol %) and cesiumfluoride (648.745 mg; 4.271 mmol; 200.00 mol %) were added together in a microwave vessel. 1,4-Dioxane (20,000 ml) was added. Under nitrogen palladium(II)-acetat (47.941 mg; 0.214 mmol; 10.00 mol%) was added. The vessel was closed with a septum und heated by microwave (150°C, 30 min). The reaction mixture was purified by flash chromatography to give 240 mg (56%) of the title compound as a yellow solid; HPLC (Method J): (percent area) 95.7 %; Rt 1.395 min.; HPLC MS (Method G): (M+H) 192.1; Rt .94 min.

2, 2-methylsulfanyl-pyrido[4,3-d1pyrimidine-5-carbaldehyde

[00123] 5-Methyl-2-methylsulfanyl-pyrido[4,3-d]pyrimidine (240.00 mg; 1.201 mmol; 1.000 eq.) was dissolved in 1,4-dioxane (4.00 ml; 46.762 mmol). Selenium dioxide (150.57 mg; 1.357 mmol; 1.130 eq.) was added and the reaction mixture was refluxed for 3.5 h. After cooling down to room temperature the reaction mixture was filtered and the mother liquor was evaporated under reduced pressure (brown solid). The residue was purified by flash chromatography to give 142 mg (58%) of the title compound as a beige solid; LC/MS (Method G): (percent area) 100 %; Rt 1.121 min; (M+H) 206.1.

3, 5-difluoromethyl-2-methylsulfanyl-pyrido[4,3-d1pyrimidine

[00124] 2-Methylsulfanyl-pyrido[4,3-d]pyrimidine-5-carbaldehyde (142.00 mg; 0.692 mmol; 1.000 eq.) was dissolved in dichlormethan (5.68 ml) and diethylamino sulfur trifluoride (304.71 pl; 2.076 mmol; 3.000 eq.) was added through a septum under nitrogen atmosphere. The solution was stirred at rt for 14 h. The reaction mixture was diluted with saturated NaHCO, solution (80 ml) and extracted with DCM three times. The combined organic layers were dried over Na2SO4, filtered and concentrated under reduced pressure. The residue was purified by flash chromatography to give 112 mg (71%) of the title compound as a beige solid; LC/MS (Method G): (percent area) 100 %; Rt 1.8 min.; (M+H) 228.1.

4, 5-difluoromethyl-8-iodo-2-methylsulfanyl-pyrido[4,3-d1pyrimidine

[00125] 5-Difluoromethyl-2-methylsulfanyl-pyrido[4,3-d]pyrimidine (27.00 mg; 0.119 mmol; 0.194 eq.) was dissolved in N,N-dimethylformamide (3.00 ml; 0.039 mol). Trifluoroacetic acid (56.55 pl; 0.734 mmol; 1.200 eq.) and N-iodosuccinimide (192.67 mg; 0.856 mmol; 1.400 eq.) were added and the reaction mixture was stirred at 50°C for 3 days. Trifluoroacetic acid (28,28 pl; 0,367 mmol; 0,600 eq.) and N-Iodosuccinimide for synthesis (96.33 mg; 0.428 mmol; 0.700 eq.) were added again and it was stirred for another 4 days. The reaction was treated with water and 0.1N sodiumthiosulfate solution and stirred for about 20 minutes while cooling down to room temperature. The precipitate was filtered off and washed with water and DCM. This gives 197 mg (85%) of the title compound as a yellow solid; LC/MS (Method G): (percent area) 93.5 %; Rt 2.291 min.; (M+H) 354.

5, 2-chloro-5-difluoromethyl-8-iodo-pyrido[4,3-d1pyrimidine

[00126] 5-Difluoromethyl-8-iodo-2-methylsulfanyl-pyrido[4,3-d]pyrimidine (197.00 mg; 0.522 mmol; 1.000 eq.) was dissolved in acetonitrile (10.94 ml). After cooling to 0°C dichloromethane (14.26 ml) and sulfuryl chloride (421.56 pl; 5.216 mmol; 10.000 eq.) were addded and it was stirred for 3 h at this temperature. DCM was evaporated and the resulting solution was used in next reaction step without any purification. Yield: 178 mg (100%) of the title compound as a yellow solution; LC/MS (Method G): (percent area) 100 %; Rt 2.037 min.; (M+H) 341.9.

6, r(lS,2R)-2-(5-difluoromethyl-8-iodo-pyridor4,3-d1pyrimidin-2-ylamino)-cyclohexyl1- carbamic acid tert-butyl ester

[00127] To the solution of 2-chloro-5-difluoromethyl-8-iodo-pyrido[4,3-d]pyrimidine (178.12 mg; 0.522 mmol; 1.000 eq.) in acetonitrile (10 ml), N-ethyldiisopropylamine (975.74 pl; 5.738 mmol; 11.000 eq.) and ethanol (347.27 pl; 5.955 mmol) were added and ((lS,2R)-2- amino-cyclohexyl)-carbamic acid tert-butyl ester (117.37 mg; 0.548 mmol; 1.050 eq.) was added. The reaction mixture was heated by microwave at 120°C for 5 min. The reaction mixture was evaporated under reduced pressure. The residue was washed with water and dried in vacuo to give 233 mg (77%) of the title compound as a brown solid; LC/MS (Method G): (percent area) 89.4 %; Rt 2.503 min.; (M+H) 520.2.

7, ((lS,2R)-2-18-(6-cyano-lH-indol-3-yl)-5-difluoromethyl-pyridor4,3-d1pyrimidin-2- ylaminol-cy cl ohexyl) -carbamic acid tert-butyl ester

[00128] [(lS,2R)-2-(5-Difluoromethyl-8-iodo-pyrido[4,3-d]pyrimidin-2-ylamino)-cyclo- hexyl]-carbamic acid tert-butyl ester (96.00 mg; 0.185 mmol; 1.000 eq.), l-BOC-6- cyanoindole-3-boronic acid pinacol ester (81.68 mg; 0.222 mmol; 1.200 eq.), palladium(II)- acetate (47% Pd) (2.08 mg; 0.009 mmol; 0.050 eq.), 2-dicyclohexylphosphino-2',6'- dimethoxybiphenyl (7.59 mg; 0.018 mmol; 0.100 eq.) and potassium carbonate (75.31 mg; 0.545 mmol; 2.948 eq.) were suspended in ethylenglycoldimethylether (1.91 ml; 18.485 mmol; 100.000 eq.) and water (0.67 ml; 36.971 mmol; 200.000 eq.) while purging nitrogen through the suspension. The suspension was heated by microwave for 45 min at 150°C. The reaction mixture was concentrated under reduced pressure. The residue was purified by flash chromatography to give 65 mg (66%) of the title compound as a yellow solid; LC/MS (Method G): (percent area) 100 %; Rt 2.395 min; (M+H) 534.3.

8, 3-r2-((lR,2S)-2-amino-cyclohexylamino)-5-difluoromethyl-pyrido- d1pyrimidin-8-

yll-lH-indole-6-carbonitrile (Compound 1)

[00129] {(lS,2R)-2-[8-(6-Cyano-lH-indol-3-yl)-5-difluoromethyl-pyrido[4,3-d]pyrimidin- 2-ylamino]-cyclohexyl}-carbamic acid tert-butyl ester (65.00 mg; 0.122 mmol; 1.000 eq.) was suspended in dichloromethane (0.95 ml; 14.876 mmol). Trifluoroacetic acid (93.85 pl; 1.218 mmol; 10.000 eq.) was added. The reaction mixture was stirred at rt for 14 h. The reaction mixture was treated with saturated NaHCO, solution and DCM and phases were separated. The aqueous layer was extracted with DCM 1 more time. The combined organic extracts were dried over Na2SO4 and evaporated under reduced pressure to give 46 mg (87%) of the title compound as a yellow solid; LC/MS (Method G): (percent area) 100 %; Rt 1.971 min.; (M+H) 434.2;

'H NMR (500 MHz, DMSO-d₆) 8 [ppm] 12.19 (s, 1H), 9.52 (s, 1H), 8.90 (s, 1H), 8.39 (s, 1H), 8.04 - 7.93 (m, 2H), 7.87 (d, J= 7.60 Hz, 1H), 7.55 - 7.29 (m, 2H), 3.88 - 3.78 (m, 1H), 3.15 - 2.99 (m, 1H), 1.93 - 1.10 (m, 8H).

Similarly, also Compounds 2 to 31 as shown in Table 1 were obtained by chemical synthesis with suitable building blocks following the principles of WO 2014/023385 Al. Successful preparation was confirmed by analytical methods as described for Compound 1 above.

Example 2: Antiviral testing of compounds in HeLa-ACE2 cells

SARS-CoV-2/HeLa-ACE2 high-content screening assay

[00130] Compounds were acoustically transferred into 384-well pclear-bottom plates (Greiner, Part. No. 781090-2B) and HeLa-ACE2 cells were seeded in the plates in 2% FBS at a density of 1.0* 10³ cells per well. Plated cells were transported to the BSL3 facility where SARS-CoV-2 (strain USA-WA1/2020 propagated in Vero E6 cells) diluted in assay media was added to achieve ~30 - 50% infected cells. Plates were incubated for 24 h at 34°C 5% CO2, and then fixed with 8% formaldehyde. Fixed cells were stained with human polyclonal sera as the primary antibody, goat anti-human H+L conjugated Alexa 488 (Thermo Fisher Scientific Al 1013) as the secondary antibody, and antifade-46-diamidino-2-phenylindole (DAPI; Thermo Fisher Scientific D1306) to stain DNA, with PBS 0.05% Tween 20 washes in between fixation and subsequent primary and secondary antibody staining.

[00131] Plates were imaged using the ImageXpress Micro Confocal High-Content Imaging System (Molecular Devices) with a 10x objective, with 4 fields imaged per well. Images were analyzed using the Multi -Wavelength Cell Scoring Application Module (MetaXpress), with DAPI staining identifying the host-cell nuclei (the total number of cells in the images) and the SARS-CoV-2 immunofluorescence signal leading to identification of infected cells.

Uninfected host cell cytotoxicity counter screen

[00132] Compounds were acoustically transferred into 1,536-well pciear plates (Greiner Part. No. 789091). HeLa-ACE2 cells were maintained as described for the infection assay and seeded in the assay-ready plates at 400 cells/well in DMEM with 2% FBS. Plates were incubated for 24 hours at 37°C 5% CO2. To assess cell viability, the Image-iT DEAD green reagent (Thermo Fisher) was used according to manufacturer instructions. Cells were fixed with 4% paraformaldehyde, and counterstained with DAPI. Fixed cells were imaged using the ImageXpress Micro Confocal High-Content Imaging System (Molecular Devices) with a 10x objective, and total live cells per well quantified in the acquired images using the Live Dead Application Module (MetaXpress).

Data analysis

[00133] Primary in vitro screen and the host cell cytotoxicity counter screen data were uploaded to Genedata Screener, Version 16.0. Data were normalized to neutral (DMSO) minus inhibitor controls (2.5 pM remdesivir for antiviral effect and 10 pM puromycin for infected host cell toxicity). For the uninfected host cell cytotoxicity counter screen, 40 pM puromycin (Sigma) was used as the positive control. For dose response experiments compounds were tested in technical triplicates on different assay plates and dose curves were fitted with the four parameter Hill Equation. Data for three assay readouts were reported: 1) % infected cells, 2) total cells per well in the HeLa-ACE2/SARS-CoV-2 infection assay, and 3) live cells per well in the uninfected HeLa-ACE2 counter-screen cytotoxicity assay.

The SARS-CoV-2 EC50 (EC50: half maximal effective concentration) was determined from the "% infected cells" curve, the HeLa-ACE2 CC50 (CC50: 50% cytotoxicity concentration) from the "live cells per well in the uninfected HeLa-ACE2 counter- screen cytotoxicity assay" curve. The Selectivity Index (SI) refers to uninfected HeLa-ACE2 CC50 divided by SARS-CoV-2 EC50.

Assay Validation

[00134] The assay was validated by using compounds with reported activity against Ebola and suspected or previously verified activity against SARS-CoV-2: remdesivir (GS-5734) (EC50 = 194 ± 20 nM; average ± sem of 5 independent experiments) and the PIKfyve inhibitor apilimod (EC50 = 50 ± 11 nM, average ± sem of 4 independent experiments). Compound toxicity was also assessed in the context of infection by quantifying the total cell numbers per well, with cytotoxic protein synthesis inhibitor puromycin serving as a positive control (average EC50 = 547 ± 27 nM, average ± sem of 5 independent experiments; HeLa-ACE2 CC50 = 2.45 ± 0.23 pM, average ± sem of 5 independent experiments). Figure 1 contains images from the assay for DMSO and remdesivir-treated wells (A), EC50 data for controls from independent experiments (B), and representative dose response curves (C).

[00135] Figure 2 contains representative dose response curves for Compound 1, i.e. the compound according to Formula (1).

[00136] Antiviral test results of selected compounds are summarized in Table 2.

Table 2:

As can be seen from these data, Syk inhibitors, in particular Compound 1, are effective against SARS-CoV-2. Compound 1 efficiently reduces the fraction of cells that are detected as being infected with SARS-CoV-2. Strong reduction in virus-infected cells is already achieved at a concentration of Compound 1 where uninfected cells are only marginally affected. Since these effects are observed in a cell culture system that only includes the infected cells, but no immune cells, this means that the effects of the Syk inhibitor against the infected cells occur without an involvement of the immune system. Thus, Syk inhibitors can be used not only against SARS-CoV-2-induced hyperinflammation at later stages of COVID-19 disease, but also against the viral infection itself at the early stages of the disease.

It is likely that the observed effects of the Syk inhibitor are caused by the direct effect of the inhibitor on its cellular targets. This means that there is a low risk that the virus can develop resistance to the effects of the Syk inhibitor by mutations in the viral genome.

By the same assay, the EC50 and SI were determined for all of Compounds 1 to 31. Results are summarized in Table 3.

Table 3:

For Compounds 1 and 31 multiple measurements were carried out.

For Compound 6, no inhibitory activity was observed. This may be because the measurement for this sample failed for technical reasons.

The data in Table 3 confirm that the observations made for Compound 1 apply also to the related Compounds 2 to 31.

Example 3: Antiviral testing of compounds in Calu3 cells SARS-CoV-2/Calu-3 high-content screening assay

[00137] Compounds were acoustically transferred into 384-well pel ear-bottom plates (Greiner, Part. No. 781090-2B) and Calu-3 cells were seeded in assay media (MEM with 2% FBS) at a density of 5,000 cells per 20 pL per well. The plated cells were transported to the BSL3 facility where SARS-CoV-2 (strain USA-WA1/2020 propagated in Vero E6 cells) diluted in assay media was added at an MOI between 0.75 and 1 to achieve ~30 - 60% infected cells. Plates were incubated for 48 h at 34°C 5% CO2, and then fixed with a final concentration of 4% formaldehyde. Fixed cells were stained with human polyclonal sera as the primary antibody, goat anti-human H+L conjugated Alexa 488 (Thermo Fisher Scientific Al 1013) as the secondary antibody, and antifade-46-diamidino-2-phenylindole (DAPI; Thermo Fisher Scientific D1306) to stain DNA, with PBS 0.05% Tween 20 washes in between fixation and subsequent primary and secondary antibody staining.

[00138] Plates were imaged using the ImageXpress Micro Confocal High-Content Imaging System (Molecular Devices) with a 10x objective, with 4 fields imaged per well. Images were analyzed using the Multi -Wavelength Cell Scoring Application Module (MetaXpress), with DAPI staining identifying the host-cell nuclei (the total number of cells in the images) and the SARS-CoV-2 immunofluorescence signal leading to identification of infected cells.

Uninfected host cell cytotoxicity counter screen

[00139] Compounds were acoustically transferred into 1,536-well plates (Corning No. 9006BC) and Calu-3 cells were seeded in assay media (MEM with 2% FBS) at a density of 600 cells per 5 pL per well. Plates were incubated for 48 hours at 37°C 5% CO2. To assess cell viability, 2 pL of 50% Cell-Titer Gio (Promega No G7573) diluted in water was added to the cells and luminescence measured on an EnVision Plate Reader (Perkin Elmer)

Data analysis

[00140] Data from the SARS-CoV-2 antiviral assay and host cell cytotoxicity counter screen were uploaded to Genedata Screener, Version 16.0. For the SARS-CoV-2 antiviral readout, the % CoV-2 positive cells were normalized to neutral (DMSO) minus inhibitor controls (10 pM remdesivir). For the cell count readout, the total cells were normalized to the stimulator (10 pM remdesivir) minus neutral control (DMSO). The uninfected host cell cytotoxicity counter screen was normalized to neutral (DMSO) minus inhibitor control (30 pM puromycin). For dose response experiments, compounds were tested in technical triplicates on different assay plates and dose curves were fitted with the four parameter Hill Equation. Curves were fitted as either increasing or decreasing and noted as such in the data output. This is of particular note for the cell count readout from the SARS-CoV-2 infection assay which captures both an antiviral effect, protection from virus-induced cell death (increasing), and cellular toxicity (decreasing).

Assay Validation

[00141] The Calu-3 SARS-CoV-2 assay was validated over the course of 12 independent experiments. Cell growth and % infection changed over time resulting in shifts in efficacy for the entry inhibitors and requiring adjustments in MOI. Thus, Calu-3 passage number has been identified as a major determinant for assay performance. Three compound controls were run with each experiment: Remdesivir, Nafamostat, and Puromycin. The half maximal effective concentration (ECso) values fell within 3 -fold of the average for all across 5 independent experiments run using optimal conditions in both antiviral readouts. The assay performed well and RZ’ was routinely >0.4. Performance of controls, infectivity and cell growth were closely monitored and conditions adjusted as needed. Data were only reported when performance of the controls was within 4-fold of the average which could result in slower turn-around of data. A comparison of compound activity in the Calu-3 and HeLa-ACE2 SARS-CoV-2 assays highlights the different routes of viral entry. Infection of Calu-3 cells is TMPRSS2-dependent and inhibited by Camostat and Nafamostat while infection of HeLa-ACE2 is likely through a cathepsin-mediated endocytic pathway thought to be inhibited by hydroxychloroquine and apilimod.

[00142] The assay was carried out with multiple compounds that turned out to be active in this assay. Determined ECso and SI values are summarized in Table 4.

Table 4:

For Compound 1, two activity measurement values were obtained.

These results show that also in Calu3 cells these compounds reduce the fraction of cells that are detected as being infected with SARS-CoV-2. Moreover, the ECso is consistently lower than the CC50, as is evident from the selectivity index.

These data confirm a trend for all compounds of this class that implies a causal relationship.

Example 4: Antiviral testing of compounds in A549 cells

[00143] An experiment similar to the experiment described in Example 2 was carried out with A549-ACE2 cells. Compounds 1 and 3 (see Table 1 above) were tested. ECso and SI values are summarized in Table 5.

Table 5:

These results show that also in A549-ACE2 cells these compounds reduce the fraction of cells that are detected as being infected with SARS-CoV-2. Moreover, the EC50 is consistently lower than the CC50, as is evident from the selectivity index.

Claims

CLAIMS WE CLAIM

1. A Syk inhibitor or a pharmaceutically acceptable salt or solvate or hydrate thereof for use in the treatment of a coronavirus infection.

2. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to claim 1, wherein the coronavirus is SARS-CoV-2.

3. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 or 2, wherein the Syk inhibitor is a pyridopyrimidine.

4. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 to 3, wherein the Syk inhibitor is a compound according to Formula (A)

Formula (A) wherein

T is selected from the group consisting of H, NH2 and CH3, wherein 1 to

3 H atoms of said CH3 may be replaced by F;

I is selected from the group consisting of P¹, P² and P³;

U is a group defined by formula xa), formula xb), formula xc) or formula xd), wherein said group defined by formula xa), formula xb), formula xc) or formula xd) is unsubstituted or mono-, di- or tri substituted by Hal, CN, OR^3a, N(R^3a)2, NHR^3a and/or R^3a, wherein 1, 2 or 3 of the

79 cyclic CH2 groups may be independently replaced by C=O, O, S, NR^3a, SO and/or SO2;

Vi is selected from the group consisting of NH and O;

V2 is selected from the group consisting of NH2, OH, NHR^3a, N(R^3a)2 and

OR^3a;

Het is a 5-membered aromatic heterocycle wherein the heterocyclic system contains 1, 2 or 3 N, O and/or S atoms. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 to 4, wherein the Syk inhibitor is a compound selected from the Table of Compounds below:

Table of Compounds:

SUBSTITUTE SHEET (RULE 26)

SUBSTITUTE SHEET (RULE 26)

SUBSTITUTE SHEET (RULE 26)

The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 to 5, wherein the Syk inhibitor is the compound according to Formula (1):

or a pharmaceutically acceptable salt and/or solvate or hydrate thereof. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 to 6, wherein said use involves administration of said Syk inhibitor to a subject in need thereof. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to claim 7, wherein the administration of the Syk inhibitor results in the reduction of the viral load in the subject. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 7 or 8, wherein the Syk inhibitor is administered prior to the subject developing a cytokine storm. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 7 to 9, wherein said Syk inhibitor is administered during the first 10 days after infection with SARS-CoV-2. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 7 to 10, wherein said Syk inhibitor is administered during the time span of day 3 to 7 after infection with SARS-CoV-2. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 to 11, wherein the subject has a mild to moderate SARS-CoV-2 infection. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 to 12, wherein the administration of the Syk inhibitor results in one or more clinical benefits, wherein the one or more clinical benefits is selected from: shortening the duration of infection, reduction of the likelihood of hospitalization, reduction in the likelihood of mortality, reduction in the likelihood of ICU admission, reduction in the likelihood of being placed on mechanical ventilation, reduction in the likelihood that supplemental oxygen will be needed, and/or reduction in the length of hospital stay. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 to 13, wherein the Syk inhibitor is administered daily. The Syk inhibitor (or the pharmaceutically acceptable salt or solvate or hydrate thereof) for use according to any one of claims 1 to 14, wherein the Syk inhibitor is administered for about 7 days to about 21 days.

90