Patent Publication Number: US-2022233480-A1

Title: Use of angiotensin ii type 2 receptor agonist

Description:
This application is a continuation-in-part of PCT/GB2021/050699, filed Mar. 22, 2021, which is a continuation-in-part of U.S. patent application Ser. No. 17/113,416, filed Dec. 7, 2020, and claims priority benefit of GB 2004209.9, filed Mar. 23, 2020 and GB 2009574.1, filed Jun. 23, 2020. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the new use of a known compound. 
     BACKGROUND AND PRIOR ART 
     A virus is a very small organism comprising genetic material (DNA or RNA) that is capable of infecting a biological organism. 
     Firstly, a virus invades and attaches itself to a living host cell, often through an appropriate adhesion receptor. It will then enter a cell through an entry receptor, after which it multiplies to produce more virus particles (virions), which attach to and enter further susceptible cells. 
     In general, viruses only infect one type of cell, but can be transmitted in various ways, including contact with infected individuals or their bodily secretions, animals (such as arthropods), or inanimate objects. Viruses can also be transmitted by inhalation or swallowing. 
     Once cells are infected by viruses, some sort of damage or injury may occur, either by killing cells or altering their functions, which may in turn lead to further, and/or more rapid, infection of other cells. 
     If such damage is significant enough, it will then generally lead to what is termed as a viral disease. Viral diseases have their own recognized symptoms, which may vary between subjects, but which are often what leads to suspicion of the existence of a viral infection, which may then be confirmed through appropriate testing procedures. 
     Symptoms of viral diseases may be a direct result of damage to cells and/or tissues caused by the virus per se, which can sometimes lead to severe illness and, in some instances, morbidity and/or death. 
     However, symptoms may also be associated with the response of an organism&#39;s immune defence system following a viral infection. White blood cells like lymphocytes and monocytes attempt to attack and destroy the invasive virus. This is part of the body&#39;s immune response. The immune response per se can often lead to cell damage as well as a patient feeling unwell or fatigued. If a patient&#39;s immune system is compromised, or not effective enough to prevent the spread of a virus, this can also lead to severe illness, morbidity and/or death. 
     Indeed, there are many different types of viruses that can seriously affect lung function and cause respiratory illnesses. Common respiratory viruses include corona virus (usually contracted in general usage to ‘coronavirus’, as used hereinafter), influenza virus, respiratory syncytial virus, parainfluenza virus, adenovirus, rhinovirus, human metapneumovirus and enterovirus. 
     Coronaviruses are a group of related viruses that cause diseases in mammals and birds. There are 7 presently-known strains of human coronaviruses:
         severe acute respiratory syndrome coronavirus (SARS-CoV),   severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, previously known as ‘2019-nCoV’ or ‘novel coronavirus 2019’), which is the virus that causes coronavirus disease 2019 (COVID-19), of which there are many genetic variants,   human coronavirus 229E (HCoV-229E, human coronavirus OC43 (HCoV-OC43),   human coronavirus NL63 (HCoV-NL63 or New Haven coronavirus),   human coronavirus HKU1,   Middle East respiratory syndrome-related coronavirus (MERS-CoV), previously known as novel coronavirus 2012, and   Human coronavirus Erasmus Medical Center/2012 (HCoV-EMC/2012).       

     In humans, coronaviruses cause respiratory tract infections that are typically mild, but some forms, such as SARS-CoV and SARS-CoV-2, can be lethal, which is thought to be due to uncontrolled aggressive deleterious pulmonary inflammation and cellular apoptosis (Fu et al,  Virol. Sin.,  35, 266 (2020)). 
     Angiotensin converting enzyme (ACE) is a central component of the renin-angiotensin system (RAS) that converts angiotensin I to the vasoconstrictor angiotensin II (Ang II), which is known to increase blood pressure. Consequently, ACE inhibiting drugs are widely used for treatment of cardiovascular diseases, in particular hypertension. 
     Angiotensin converting enzyme 2 (ACE2) is a peptidase that catalyses the conversion of angiotensin I to the nonapeptide angiotensin[1-9] and the conversion of angiotensin II to the heptapeptide angiotensin[1-7]. 
     Alveolar epithelial cells are an important target for coronavirus infection in the lungs (Miura and Holmes,  J. Leukoc. Biol.,  86, 1145 (2009)). Indeed, in human lung tissue, 83% of ACE2-expressing cells have been reported to be alveolar epithelial cells (Zhao et al (2020), https://doi.org/10.1101/2020.01.26.91998 5 and Zhang et al,  Intensive Care Med.,  46, 586 (2020)). ACE2 is not sensitive to the ACE inhibitor drugs used to treat hypertension (Tipnis et al,  J. Biol. Chem.,  275, 33238 (2000)). 
     The angiotensin II receptor type 1 receptor (AT1R) is a well characterized angiotensin receptor. It mediates Ang II-induced vasoconstriction and regulates aldosterone secretion and thereby controls blood pressure. AT1R blockers (ARBs) are drugs used for treatment of e.g. hypertension and diabetic nephropathy. 
     Both SARS-CoV and SARS-CoV-2 viruses are known to bind to and enter their target cells through ACE2 (see e.g. Hamming et al,  J. Pathol.,  203, 631 (2004), Zhang et al, supra and Zhou et al,  Nature,  579, 270 (2020)). 
     As recently summarized by Fang et al in  Lancet Respir. Med.,  8, e21 (2020), the most distinctive comorbidities of patients with COVID-19 are diabetes and hypertension. As mentioned above, the latter comorbidities are often treated with ACE inhibitors and/or ARBs. 
     The expression of ACE2 is substantially increased in patients who are treated with ACE inhibitors and/or ARBs, which would be expected to facilitate infection with SARS viruses. Accordingly, Fang et al, supra suggested that treatment of e.g. diabetic and hypertensive patients with ACE2-stimulating drugs may increase the risk of developing severe and fatal SARS infections such as COVID-19. 
     Although addressed to some extent in a rapid review of the available evidence carried out by the World Health Organization, which concluded (on 7 May 2020) that such patients are likely not at higher risk of poor outcomes from COVID-19, it is noteworthy that these concerns continue to be expressed. See, for example, Diaz,  Journal of Travel Medicine,  2020, 1-2, doi: 10.1093/jtm/taaa041, Hoffmann et al,  Cell,  181, 1 (2020) and Gnanenthiran et al,  BMJ Open  2021; 11:e043625. doi:10.1136/bmjopen-2020-043625. The latter publication was recently written by a pool of worldwide experts, including specialists in the RAS, who proposed that a meta-analysis of clinical trials is conducted with a view to improving clinical certainty and decision-making in relation to whether ACE inhibitor and/or ARB therapy should be initiated, continued or ceased in COVID-19. 
     The angiotensin II type 2 receptor (AT2R or AGTR2) mediates antiinflammatory, anti-fibrotic, antiproliferative and vasodilatory activities when activated by an AT2R agonist (see e.g. Verdonk et al,  Expert Opin. Investig. Drugs  21, 501 (2012). 
     Activation of the AT2R receptor is also understood to enhance ACE2 expression and activity, in a similar fashion to ACE inhibitors and/or ARBs (Zhu et al,  Am. J. Physiol. Heart Circ. Physiol.  309, H827 (2015). It has also been reported in a paper by Cui et al (see  Preprints  (2020), https://doi:10.20944/preprints202002.0194.v1) that the AT2R may, in a similar fashion to ACE2, contribute to entry of SARS-CoV-2 into human cells. 
     Imai et al ( Nature,  436, 112 (2005)) reported that an AT2R blocker had no effect on disease progression following non-viral stimulation of lung injury, suggesting that the apparent protective role of AT2R was unrelated to any AT2R agonistic activation. It has also been demonstrated in models of cystic fibrosis (CF) that blocking (rather than stimulating) the AT2R prevents CF manifestation, i.e. reduced ATR2 signaling is beneficial to CF lung function (Darrah et al,  Journal of Cystic Fibrosis,  18, 127 (2019). Likewise, blocking of the AT2R has also been shown to significantly reduce chemically-induced pulmonary inflammation (Waseda et al,  Respiratory Research,  9, 43 (2008)). 
     International patent application WO 2002/096883 describes the preparation of imidazolyl, triazolyl, and tetrazolyl thiophene sulfonamides and derivatives thereof as angiotensin II receptor agonists. Of the compounds described in that document (as Example 1) is Compound 21 (N-butyloxycarbonyl-3-(4-imidazol-1-ylmethyl phenyl)-5-isobutylthiophene-2-sulfonamide; hereafter ‘C21’. C21 was selected for clinical development from a group of about 20 related analogues as a selective AT2 agonist. It is now in clinical development for treatment of AT2 related disorders, including idiopathic pulmonary fibrosis (IPF) (see, for example, international patent application WO 2016/139475). 
     As Zhu et al supra reported in relation to a different selected AT2R agonist, CGP42112, C21 has been shown to increase the expression of both AT2R itself and ACE2 (in C21&#39;s case in inflamed lung tissue; Bruce et al,  Br. J. Pharmacol.,  172, 2219 (2015)). 
     Although the mechanism by which respiratory viruses, including SARS-CoV and SARS-CoV-2, may cause serious disease and sometimes be fatal is still poorly understood, as mentioned above, COVID-19 (at least) is thought to progress through uncontrolled pulmonary inflammation and cellular apoptosis (Fu et al, supra). Both C21 and the other AT2R agonist CGP42112 have both been shown to induce and/or promote apoptosis (Chamoux et al,  J Clin Endocrinol Metab,  84, 4722 (1999); Ito et al,  Oncotarget,  9, 13859, (2018)). 
     Finally, and importantly, C21 was found not to improve pulmonary gas exchange or have other relevant beneficial clinical effects in an ARDS model of acute lung injury (Menk et al,  J. Inflamm. Res.,  11, 169 (2018)). 
     The above notwithstanding, during the course of a rapidly-developing global COVID-19 pandemic in early 2020, we reviewed and reassessed some previously unpublished data relating to C21, which showed that it dose-dependently reduced E-cadherin expression in a human small airway epithelial cells. E-cadherin is a calcium-dependent epithelial cell adhesion molecule that is known to play a critical role in viral infection at the level of host cell binding and viral entry into cells (Hu et al,  Front. Cell. Infect. Microbiol.,  10, Article 74 (2020)). 
     These data, reported for the first time herein, led us to the conclusion that, despite its potential to increase ACE2 levels, and the genuine clinical concerns that are associated with doing this, such E-cadherin downregulation by C21 might inhibit binding and entry of viruses, such as SARS-CoV-2, into relevant cells. By disrupting the mechanism by which the virus infects cells, C21 might further arrest the progress of the disease leading to less serious symptoms. 
     Surprisingly, we have found that C21 does indeed have beneficial effects on human airway epithelium, and protects against SARS virus-induced pulmonary epithelial damage and dysfunction in patients in a clinical setting. 
     In particular, as further described herein, in a double-blind placebo-controlled clinical study carried out in COVID-19 patients, we found, highly surprisingly, that C21 is not only capable of abrogating or preventing the development of severe respiratory viral diseases, but also that it appears to be capable of promoting accelerated resolution of such diseases. 
     In particular, it was found that the need for oxygen treatment was significantly lower in patients that were administered C21 compared to placebo. The number of patients needing mechanical ventilation was also found to be reduced in the C21 group. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a graph showing the need for supplemental oxygen over time in a clinical trial conducted in COVID-19 patients that received either placebo or 100 mg C21 orally b.i.d over 7 days. 
     
    
    
     DISCLOSURE OF THE INVENTION 
     According to the invention, there is provided C21 or a pharmaceutically-acceptable salt thereof for use in a method of treatment of respiratory virus-induced tissue damage. 
     Tissue damage includes injury and/or dysfunction of relevant tissues and/or the cells that comprise them. Relevant tissues include (e.g. mucosal) tissues of the respiratory tract, and especially those of the lung. Relevant tissue thus includes the respiratory epithelium, which moistens the airways and protects against invasion of pathogens such as viruses. 
     Respiratory viruses that may be mentioned include influenza viruses and, more particularly, coronaviruses such as those mentioned hereinbefore, including SARS coronaviruses, such as SARS-CoV and, especially, SARS-CoV-2. 
     By ‘treatment’ of tissue damage, we include that C21 and salts thereof may not only have a beneficial effect on tissue damage in the respiratory tract that has been caused by such a virus, but that it may also prevent and/or mitigate the damage that would otherwise have been caused by that virus in the respiratory tract, which occurs when the relevant virus enters e.g. epithelial cells in the respiratory tract. 
     The data described hereinafter show that C21 and salts thereof may further promote accelerated resolution of such respiratory tissue damage and/or injury, and therefore accelerated resolution of respiratory diseases, with C21 and salts thereof being capable of restoring lung function and/or respiratory function. 
     For the avoidance of doubt therefore, ‘treatment’ of tissue damage includes the therapeutic, symptomatic and palliative treatment of such damage, as well as, in principle, the prophylaxis of such damage, or during the diagnostic workup of such damage (i.e. if it is suspected). More importantly, C21 and salts thereof may abrogate or prevent the development of diseases that are caused by such tissue damage and/or the symptoms of such damage or diseases. 
     In this respect, C21 and salts thereof may treat, and/or arrest the progress of, diseases that are being, or have been, caused by respiratory viruses (i.e. diseases such as influenza, as well as acute lung injury (ALI), acute respiratory distress syndrome (ARDS), particularly SARS and, more particularly, COVID-19) and their sequelae. 
     C21 and salts thereof may also treat and/or prevent the damage that is being, or has been, caused by such viruses, which includes treating and/or preventing the symptoms of such respiratory diseases, which symptoms may be primary (and/or ‘acute’) and thus include cough, dyspnea, respiratory distress (as manifest by e.g. the need for supplementary/supplemental oxygen (which may be administered by a face mask or via nasal cannula (high flow or otherwise)), and/or mechanical ventilation/extra-corporeal membrane oxygenation), respiratory failure, and/or pneumonia, which may occur directly (viral pneumonia) and/or indirectly (bacterial pneumonia resulting from secondary bacterial infections in individuals whose immune system is compromised by the respiratory viral infection, which is common in influenza). 
     Such symptoms may also be secondary (and/or ‘chronic’) and thus include fibrosis in the lungs and other organs, such as the heart and kidneys. Such fibrosis is known to be a particular problem in many COVID-19 patients, and may result from one or more of a number of factors, including inflammation. 
     In this respect, C21 and salts thereof may prevent or arrest the progress of respiratory virus-induced morbidity and/or mortality, and C21 may treat, and/or arrest the development of any of the acute and/or chronic symptoms identified above. 
     The data described hereinafter suggest that C21 and salts thereof may be prescribed at any time subsequent a positive diagnosis of infection with a respiratory virus, including as soon as possible thereafter, with a view to preventing one or more of the symptoms described above, and/or the severity of any such symptoms. 
     Salts of C21 that may be mentioned include pharmaceutically-acceptable acid addition salts and base addition salts. Such salts may be formed by conventional means, for example by reaction of free compound with one or more equivalents of an appropriate acid or base, optionally in a solvent, or in a medium in which the salt is insoluble, followed by removal of said solvent, or said medium, using standard techniques (e.g. in vacuo, by freeze-drying or by filtration). Salts may also be prepared by exchanging a counter-ion of active ingredient in the form of a salt with another counter-ion, for example using a suitable ion exchange resin. Preferred salts of C21 include acid addition salts, such as HCl salts, alkaline earth salts, such as magnesium and calcium salts, and alkali metal salts, such as potassium or, preferably, sodium salts. 
     Although C21 and salts thereof may possess biological activity as such, certain pharmaceutically-acceptable (e.g. ‘protected’) derivatives of C21 may exist or be prepared which may not possess such activity, but may be administered and thereafter be metabolised in the body to form C21. Such compounds (which may possess some biological activity, provided that such activity is appreciably lower than that of C21) may therefore be described as ‘precursors’ or ‘prodrugs’ of C21. 
     As used herein, references to precursors or prodrugs will include compounds that form C21, in an experimentally-detectable amount, within a predetermined time, following administration. All precursors and prodrugs of C21 are included within the scope of the invention. 
     According to a further aspect of the invention there is provided a method of medical treatment of respiratory virus-induced tissue damage as hereinbefore defined, which method comprises administering C21 or a pharmaceutically-acceptable salt thereof to a subject in need of such treatment. 
     ‘Subjects’ (which may be employed interchangeably herein with ‘patients’) include avian and, especially, mammalian (particularly human) subjects and/or patients. Human patients include both adult patients as well as paediatric patients, the latter including patients up to about 24 months of age, patients between about 2 to about 12 years of age, and patients between about 12 to about 16 years of age. Patients older than about 16 years of age may be considered adults for purposes of the present invention. These different patient populations may be given different doses of C21, or salt thereof. 
     It is preferred, in accordance with the invention, that C21 or a pharmaceutically-acceptable salt thereof is administered to adult patients/subjects, more particularly subjects that are over the age of about 20, such as over the age of about 30, including over the age of about 40, more preferably over the age of about 50, especially over the age of about 60, particularly over the age of about 70, and more particularly over the age of about 80. 
     It is further preferred that C21 or a pharmaceutically-acceptable salt thereof is administered to patients/subjects (whether or not such subjects are in one of the age groups specified above) with one or more of the following underlying medical conditions:
         chronic (long-term) respiratory diseases, such as pulmonary fibrosis, pulmonary hypertension, pulmonary arterial hypertension, asthma, chronic obstructive pulmonary disease (COPD), emphysema or bronchitis   chronic cardiovascular (e.g. heart) disease, such as heart failure, atrial fibrillation or hypertension   chronic kidney disease   chronic liver disease, such as hepatitis   chronic neurological conditions, such as Parkinsons disease, motor neurone disease, multiple sclerosis, a learning disability or cerebral palsy   diabetes   problems with a patient&#39;s spleen—for example, sickle cell disease or if the spleen has been removed   a weakened immune system as the result of conditions, such as HIV and       

     AIDS, or medicines such as steroid tablets or chemotherapy
         obesity (e.g. a body mass index (BMI) of 40 or above)   pregnancy       

     As mentioned above, the results described hereinafter demonstrate that C21 has a broad range of activity against respiratory virus infections, respiratory virus-induced cell and/or tissue damage, respiratory virus diseases (and symptoms thereof) that may result from such damage, including primary/acute and/or secondary/chronic symptoms specified herein, as well as any longer term physiological effects of such serious diseases, which may be induced, directly or indirectly, by the viral infection. 
     In this respect, according to several further aspects of the invention there is provided a method of treatment and/or prevention of one or more the following conditions:
         post-acute sequelae of e.g. SARS-CoV-2 infection (PASO), such as what is known as ‘long COVID’, ‘chronic COVID syndrome’ (CCS) and/or ‘long-haul COVID’;   acute kidney injury and/or chronic kidney disease, including fibrosis in the kidneys;   respiratory diseases such as pulmonary fibrosis, pulmonary hypertension, pulmonary arterial hypertension, asthma, chronic obstructive pulmonary disease (COPD), emphysema and/or bronchitis; and   cardiovascular diseases such as myocardial infarction, heart failure, atrial fibrillation, hypertension or thrombosis and/or embolization in e.g. the heart, lungs and/or brain, as well as fibrosis in the heart,
 
all of which may be induced, directly or indirectly, by respiratory viruses (such as SARS-CoV-2), which method comprises administering C21 or a pharmaceutically-acceptable salt thereof to a subject in need of such treatment and/or prevention.
       

     In accordance with the invention, C21 and pharmaceutically-acceptable salts thereof may be administered locally or systemically, for example orally, intravenously or intraarterially (including by intravascular and other perivascular devices/dosage forms (e.g. stents)), intramuscularly, cutaneously, subcutaneously, transmucosally (e.g. sublingually or buccally), rectally, intravaginally, transdermally, nasally (including nasogastrically), pulmonarily (e.g. tracheally or bronchially) via e.g. inhalation as a dry powder via e.g. a dry powder inhaler or as an aerosol via e.g. nebulization, topically, or by any other parenteral route, in the form of a pharmaceutical preparation comprising the compound(s) in pharmaceutically-acceptable dosage form(s). 
     Treatment may thus be induced by systemic administration of C21 and pharmaceutically-acceptable salts thereof, for example by way of oral administration (e.g. as described hereinafter), by way of a parenteral route, e.g. by way of injection or infusion for systemic administration (which may take place intramuscularly, intraosseously, intracerebrally, intracerebroventricularly, intrasynovially, intrasternally, intrathecally, intralesionally, intracranially, intratumorally, cutaneously, intracutaneously, subcutaneously, transdermally, preferably intravenously or, more preferably, intraarterially via a pharmaceutically-acceptable dosing means), or by way of pulmonary administration, for example as described in international patent application WO 2020/095042 (international patent application WO 2020/095042 A1). 
     Other modes of delivery of C21 and pharmaceutically-acceptable salts thereof include topical administration. In such a mode of administration, absorption of compound of the invention into systemic circulation may occur, or the compound of the invention may act locally at the site of administration (e.g. the respiratory mucosa). 
     Administration of C21/salts thereof via inhalation and/or, in particular, orally may be done conveniently in both hospitalized and non-hospitalized patients (out-patients); in patients exhibiting either early (e.g. pre-symptomatic and/or mild symptomatic patients) and/or late (including more severe) stages of the relevant respiratory disease (including, in the case of peroral administration, before such patients are in need of mechanical ventilation); as well as when infection may be expected or is suspected (in a largely prophylactic manner). 
     Administration of C21 and salts thereof nasogastrically or via nebulization may also be useful in the case of administration of C21 during later stages of the respiratory disease, for example in patients requiring hospitalisation, supplemental oxygenation, and particularly in patients needing critical care, including mechanical ventilation and/or extra-corporeal membrane oxygenation. 
     C21 and pharmaceutically-acceptable salts thereof will generally be administered in the form of one or more formulations in admixture with an (e.g. pharmaceutically-acceptable) adjuvant, diluent or carrier, which may be selected with due regard to the intended route of administration and standard pharmaceutical practice. Acceptable carriers may be chemically inert to the active compounds and may have limited (or preferably no) detrimental side effects or toxicity under the conditions of use. Such carriers may also impart an immediate, or a modified, release of the active ingredient. 
     Suitable pharmaceutical formulations of C21 and salts thereof include capsule formulations, such as those described in international patent applications WO 2021/214486 A1, more preferably WO 2021/214487 A1, and especially WO 2021/214488 A1, as well as injectable formulations such as those described in UK patent application GB 2115303.6, the disclosures of each of which documents are hereby incorporated by reference. 
     Otherwise, suitable pharmaceutical formulations may be commercially available or may otherwise be prepared according to techniques that are described in the literature, for example, Remington  The Science and Practice of Pharmacy,  22 nd  edition, Pharmaceutical Press (2012) and  Martindale—The Complete Drug Reference,  38 th  Edition, Pharmaceutical Press (2014) and the documents referred to therein, the relevant disclosures in all of which documents are hereby incorporated by reference. 
     Otherwise, the preparation of suitable formulations including C21 and pharmaceutically-acceptable salts thereof may be achieved non-inventively by the skilled person using routine techniques. 
     According to a further aspect of the invention there is provided a pharmaceutical composition comprising C21 or a pharmaceutically-acceptable salt thereof, along with one or more pharmaceutically-acceptable excipient(s), such as an adjuvant, diluent or carrier which composition is packaged and presented for use in a method of treatment of respiratory virus-induced tissue damage. 
     Administration of active ingredients may be continuous or intermittent. 
     The mode of administration may also be determined by the timing and frequency of administration, but is also dependent on the severity of that condition, or otherwise on the need for treatment. 
     The amount of active ingredient in a formulation will depend, and/or may be selected depending, upon the severity of the respiratory virus-induced tissue damage, or the expectation of such severity, as well as on the subject to be treated, but may be determined by the skilled person. 
     In any event, the practitioner, or other skilled person, will be able to determine routinely the actual dosage, which will be most suitable for an individual subject. Dosages mentioned herein are exemplary of the average case; there can, of course, be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention. 
     In relation to (for example) acute treatment of respiratory virus-induced tissue damage, doses of C21 or salt thereof may be administered between once and four times (e.g. between 1 and 3 times) daily for up to three (e.g. two) months, such as one month, including up to three weeks, e.g. up to one week, such as 4 days or 3 days. Such treatment periods may be repeated as appropriate. 
     In the case of the development of one or more of the secondary/chronic symptoms, and/or longer term physiological effects, identified hereinbefore, such as fibrosis of the lungs and other internal organs, treatment with C21 or salt thereof may, in addition to and/or instead of the above-mentioned acute dosing regimens, be continuous and/or as needed/required. 
     Suitable oral daily doses (calculated as the free base) of C21 in adult subjects (average weight e.g. 70 kg), may be up to about 600 mg, including about 400 mg and about 200 mg (e.g. about 100 mg), and no lower than about 50 mg. 
     In any event, the dose administered to a mammal, particularly a human, in the context of the present invention should be sufficient to effect a response in the subject over a reasonable timeframe (e.g. as described herein). One skilled in the art will recognize that the selection of the exact dose and composition and the most appropriate delivery regimen will also be influenced by inter alia the pharmacological properties of the formulation, the physical condition of the recipient, including the age, condition, body weight, sex and response of the subject to be treated, and also the nature, stage and/or severity of the disease, and genetic differences between subjects. 
     In the uses and methods described herein, C21 and salts thereof may also be combined with one or more therapeutic agents that are useful in the treatment of patients with viral infections and/or the symptoms of diseases caused thereby. 
     Therapeutic agents that may be used in conjunction with C21 in accordance with the invention include variously-applied standard treatments for viral infections, including antiviral medicines (e.g. oseltamivir, remdesivir, favilavir, favipitavir, merimepodib, molnupiravir, baloxavir, zanamivir, peramivir, simeprevir, daclatasvir, sofosbuvir, ribavirin, umifenovir, lopinavir, ritonavir, lopinavir+ritonavir (Kaletra; AbbVie Deutschland GmbH Co. KG), nirmatrelvir+ritonavir (Paxlovid), teicoplanin, baricitinib (Olumiant; Eli Lilly), ruxolitinib (Jakavi; Novartis), tofacitinib (Xeljanz; Pfizer), ivermectin, anakinra, the TMPRSS2 inhibitor, camostat and camostat mesylate, Actembra (Roche), TZLS-501, AT-100 (rhSP-D), MK-7110 (CD24Fc; Merck)), OYA1 (OyaGen9), BPI-002 (BeyondSpring), NP-120 (Ifenprodil; Algernon Pharmaceuticals), Galidesivir (Biocryst Pharma), REGN3048-3051 and Kevzara (SNG001; Synairgen Research), antiinflammatory agents (e.g. NSAIDs, such as ibuprofen, ketorolac, naproxen, and the like), colchicine, as well as chloroquine, hydroxychloroquine, interferons (e.g. interferon beta (interferon beta-1a)), tocilizumab (Acterma), lenalidomide, pomalidomide and thalidomide), analgesics (e.g. paracetamol or opioids), antitussive agents (e.g. dextromethorphan), vaccinations (e.g. COVID-19 mRNA vaccines (e.g. Comirnaty from Pfizer-BioNTech or Spikevax from Moderna), viral vector COVID-19 vaccines (e.g. COVID-19 Vaccines from J&amp;J/Janssen, Vaxzsevria from AstraZeneca or Novavax from Novartis), INO-4800 by Inovio Pharmaceuticals and Beijing Advaccine Biotechnology (if available), Sputnik V Gam-COVID-Vac (Gamaleya Institute), Sinovac, Vidprevtyn (Sanofi Pasteur), VLA2001 (Valneva), multiantigenic COVID-19 vaccines and influenza vaccines), antibody therapies (e.g. tixagevimab, cilgavimab, regdanvimab, sotrovimab, LY-CoV555/LY-CoV016 (bamlanivimab and etesevimab)), LY-CoV555 (bamlanivimab, Eli Lilly), REGN-COV2 (casirivimab and imdevimab), REGN3048-3051, TZLS-501, SNG001 (Synairgen), eculizumab (Soliris; Alexion Pharmaceuticals), ravulizumab (Ultomiris; Alexion Pharmaceuticals), lenzilumab, leronlimab, tocilizumab (Actemra; Roche), sarilumab (Kevzara; Regeneron Pharma), and Octagam (Octapharma)), and/or passive antibody therapy with antibodies from blood of people who have recovered from infection with SARS-CoV or SARS-CoV-2, including COVID-19 convalescent plasma (CCP). 
     Further therapeutic agents that may be mentioned include antifibrotics (e.g. nintedanib and, particularly, pirfenidone), vitamins (e.g. vitamin B, C and D) and mucolytics such as acetylcysteine and ambroxol. 
     Other therapeutic agents that may be used in conjunction with C21 or salts thereof in accordance with the invention include corticosteroids. Corticosteroids include both naturally-occurring corticosteroids and synthetic corticosteroids. 
     Naturally-occurring corticosteroids that may be mentioned include cortisol (hydrocortisone), aldosterone, corticosterone, cortisone, pregnenolone, progesterone, as well as naturally-occurring precursors and intermediates in corticosteroid biosynthesis, and other derivatives of naturally-occurring corticosteroids, such as 11-deoxycortisol, 21-deoxycortisol, 11-dehydrocorticosterone, 11-deoxycorticosterone, 18-hydroxy-11-deoxycorticosterone, 18-hydroxycorticosterone, 21-deoxycortisone, 11β-hydroxypregnenolone, 11β, 17α,21-trihydroxypregnenolone, 17α,21-dihydroxypregnenolone, 17α-hydroxypregnenolone, 21-hydroxypregnenolone, 11-ketoprogesterone, 11β-hydroxyprogesterone, 17α-hydroxyprogesterone and 18-hydroxyprogesterone. 
     Synthetic corticosteroids that may be mentioned include those of the hydrocortisone-type (Group A), such as cortisone acetate, hydrocortisone aceponate, hydrocortisone acetate, hydrocortisone buteprate, hydrocortisone butyrate, hydrocortisone valerate, tixocortol and tixocortol pivalate, prednisolone, methylprednisolone, prednisone, chloroprednisone, cloprednol, difluprednate, fludrocortisone, fluocinolone, fluperolone, fluprednisolone, loteprednol, prednicarbate and triamcinolone; acetonides and related substances (Group B), such as amcinonide, budesonide, desonide, fluocinolone cetonide, fluocinonide, halcinonide, triamcinolone acetonide, ciclesonide, deflazacort, formocortal, fludroxycortide, flunisolide and fluocinolone acetonide, those of the (beta) methasone-type (Group C), such as beclomethasone, betamethasone, betamethasone dipropionate and betamethasone valerate, dexamethasone, fluocortolone, halometasone, mometasone and mometasone furoate, alclometasone and alclometasone dipropionate, clobetasol and clobetasol propionate, clobetasone and clobetasone butyrate, clocortolone, desoximetasone, diflorasone, difluocortolone, fluclorolone, flumetasone, fluocortin, fluprednidene and fluprednidene acetate, fluticasone, fluticasone furoate and fluticasone propionate, meprednisone, paramethasone, prednylidene, rimexolone and ulobetasol; those of the progesterone-type, such as flugestone, fluorometholone, medrysone and prebediolone acetate, and progesterone derivatives (progestins), such as chlormadinone acetate, cyproterone acetate, medrogestone, medroxyprogesterone acetate, megestrol acetate and segesterone acetate; as well as other corticosteroids, such as cortivazol and 6-methyl-11β,17β-dihydroxy-17α-(1-propynyl)androsta-1,4,6-trien-3-one. 
     Preferred corticosteroids include cortisone, prednisone, prednisolone, methylprednisolone and, especially, dexamethasone. 
     Further, therapeutic agents that may be used in conjunction with C21 or salts thereof include H2 receptor blockers, anticoagulants, anti-platelet drugs, as well as statins, antimicrobial agents and anti-allergic/anti-asthmatic drugs. 
     H2 receptor blockers that may be mentioned include famotidine. Anticoagulants that may be mentioned include heparin and low-molecular-weight heparins (e.g. bemiparin, nadroparin, reviparin, enoxaparin, parnaparin, certoparin, dalteparin, tinzaparin); directly acting oral anticoagulants (e.g. dabigatran, argatroban, rivaroxaban, apixaban, edoxaban, betrixaban, darexaban, otamixaban, letaxaban, eribaxaban, hirudin, lepirudin and bivalirudin); coumarin type vitamin K antagonists (e.g. coumarin, acenocoumarol, phenprocoumon, atromentin and phenindione) and synthetic pentasaccharide inhibitors of factor Xa (e.g. fondaparinux, idraparinux and idrabiotaparinux). Anti-platelet drugs that may be mentioned include irreversible cyclooxygenase inhibitors (e.g. aspirin and triflusal); adenosine diphosphate receptor inhibitors (e.g. cangrelor, clopidogrel, prasugrel, ticagrelor and ticlopidine); phosphodiesterase inhibitors (e.g. cilostazol); protease-activated receptor-1 antagonists (e.g. vorapaxar); glycoprotein IIB/IIIA inhibitors (e.g. abciximab, eptifibatide and tirofiban); adenosine reuptake inhibitors (e.g. dipyridamole); and thromboxane inhibitors (e.g. terutroban, ramatroban, seratrodast and picotamide). Statins that may be mentioned include atorvastatin, simvastatin and rosuvastatin. Antimicrobial agents that may be mentioned include azithromycin, ceftriaxone, cefuroxime, doxycycline, fluconazole, piperacillin, tazobactam and teicoplanin. Anti-allergic/anti-asthmatic drugs that may be mentioned include chlorphenamine, levocetirizine and montelukast. 
     Although not standard treatments for viral infections, as discussed previously, there are concerns that certain therapeutic agents may increase the risk of developing severe and fatal SARS infections such as COVID-19 (see Fang et al, supra). In this respect, C21 and salts thereof may also be used in conjunction with other AT2 agonists that are known in the art, as well as anti-hypertensive drugs, such as ARBs (e.g. azilsartan, candesartan, eprosartan, fimasartan, irbesartan, losartan, milfasartan, olmesartan, pomisartan, pratosartan, ripiasartan, saprisartan, tasosartan, telmisartan, valsartan and/or combinations thereof) and ACE inhibitors (e.g. benazepril, captopril, zofenopril, enalapril, fosinopril, lisinopril, moexipril, perindopril, imidapril, quinapril, ramipril, trandolapril, cilazapril, spirapril, temocapril, alacepril, ceronapril, delepril, moveltipril, and/or combinations thereof). 
     Further relevant active ingredients that may be used in conjunction with C21 include anti-diabetics such as SGLT2 inhibitors (e.g. dapagliflozin, canagliflozin, empagliflozin, tofogliflozin, ertugliflozin, ipragliflozin, luseogliflozin, remogliflozin and sotagliflozin); GLP-1 receptor agonists (e.g. exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, semaglutide, taspoglutide, efpeglenatide and tirzepatide) and DPP-4 inhibitors (e.g. sitagliptin, vildagliptin, saxagliptin, linagliptin, gemigliptin, teneligliptin, alogliptin, trelagliptin, omarigliptin, evogliptin, gosogliptin and dutogliptin); drugs used in heart failure (e.g. carvedilol, metoprolol, bisoprolol, spironolactone, eplerenone, furosemide and stimulators of soluble guanylate cyclase like riociguat); medications used in PAH and/or PH (e.g. epoprostenol, treprostinil, bosentan, macitentan, ambrisentan, sildenafil, tadalafil, amlodipine, diltiazem, nifedipine and digoxin); medications used in CKD (e.g. erythropoietin, simvastatin, rosuvastatin, atorvastatin and calcium and vitamin D supplements), and/or combinations thereof. 
     Subjects may be (and/or may be already) receiving one or more of any of the other therapeutic agents mentioned above, by which we mean receiving a prescribed dose of one or more of those other therapeutic agents, prior to, in addition to, and/or following, treatment with C21/salt. 
     When C21/salts are ‘combined’ with such other therapeutic agents, the active ingredients may be administered together in the same formulation, or administered separately (simultaneously or sequentially) in different formulations. 
     Such combination products provide for the administration of C21/salt in conjunction with the other therapeutic agent, and may thus be presented either as separate formulations, wherein at least one of those formulations comprises C21/salt, and at least one comprises the other therapeutic agent, or may be presented (i.e. formulated) as a combined preparation (i.e. presented as a single formulation including C21/salt and the other therapeutic agent). 
     Thus, there is further provided: 
     (1) a pharmaceutical formulation including C21 or a pharmaceutically-acceptable salt thereof; a therapeutic agent that is useful in the treatment of a viral infection; and a pharmaceutically-acceptable adjuvant, diluent or carrier (which formulation is hereinafter referred to as a ‘combined preparation’); and
 
(2) a kit of parts comprising components:
     (A) a pharmaceutical formulation including C21 or a pharmaceutically-acceptable salt thereof in admixture with a pharmaceutically-acceptable adjuvant, diluent or carrier; and   (B) a pharmaceutical formulation including a therapeutic agent that is useful in the treatment of a viral infection, in admixture with a pharmaceutically-acceptable adjuvant, diluent or carrier,
 
which components (A) and (B) are each provided in a form that is suitable for administration in conjunction with the other.
   

     Such combined preparations and kits of parts may thus be used in the treatment of respiratory virus-induced tissue damage. 
     In certain instances, such additional therapeutic agents, including some of those that are useful in the treatment of a viral infection, may be termed ‘standard of care’ in relation to a particular respiratory viral condition. The term ‘standard of care’ will be understood by the skilled person to include a treatment processes that a clinician should, and/or is expected to, follow for certain types of patients, illnesses and/or clinical circumstances. In certain new or poorly-understood conditions, like COVID-19, standard of care may change and/or develop over time. 
     According to a further aspect of the invention, there is provided a method of making a kit of parts as defined above, which method comprises bringing component (A), as defined above, into association with a component (B), as defined above, thus rendering the two components suitable for administration in conjunction with each other. 
     By bringing the two components ‘into association with’ each other, we include that components (A) and (B) of the kit of parts may be: 
     (i) provided as separate formulations (i.e. independently of one another), which are subsequently brought together for use in conjunction with each other in combination treatment; or
 
(ii) packaged and presented together as separate components of a ‘combination pack’ for use in conjunction with each other in combination treatment.
 
     Thus, there is further provided a kit of parts comprising: 
     (I) one of components (A) and (B) as defined herein; together with
 
(II) instructions to use that component in conjunction with the other of the two components.
 
     The kits of parts described herein may comprise more than one formulation including an appropriate quantity/dose of C21/salt, and/or more than one formulation including an appropriate quantity/dose of the other therapeutic agent, in order to provide for repeat dosing. If more than one formulation (comprising either active compound) is present, such formulations may be the same, or may be different in terms of the dose of either compound, chemical composition(s) and/or physical form(s). 
     With respect to the kits of parts as described herein, by ‘administration in conjunction with’, we include that respective formulations comprising a C21/salt and other therapeutic agent are administered, sequentially, separately and/or simultaneously, over the course of treatment of the condition. 
     Thus, in respect of the combination product according to the invention, the term ‘administration in conjunction with’ includes that the two components of the combination product (C21 and other agent) are administered (optionally repeatedly), either together, or sufficiently closely in time, to enable a beneficial effect for the subject, that is greater, over the course of the treatment of the condition, than if either a formulation comprising C21/salt, or a formulation comprising the other therapeutic agent that is useful in the treatment of a viral infection, are administered (optionally repeatedly) alone, in the absence of the other component, over the same course of treatment. Determination of whether a combination provides a greater beneficial effect in respect of, and over the course of treatment will depend upon the condition to be treated and/or its severity, but may be achieved routinely by the skilled person. 
     Further, in the context of a kit of parts according to the invention, the term ‘in conjunction with’ includes that one or other of the two formulations may be administered (optionally repeatedly) prior to, after, and/or at the same time as, administration of the other component. When used in this context, the terms ‘administered simultaneously’ and ‘administered at the same time as’ include that individual doses of C21 and other therapeutic agent are administered within 48 hours (e.g. 24 hours) of each other. 
     In a further aspect of the invention, there is provided a process for the preparation of a combined preparation as hereinbefore defined, which process comprises bringing into association C21 or a pharmaceutically-acceptable salt thereof, a therapeutic agent that is useful in the treatment of a viral infection, and at least one pharmaceutically-acceptable excipient. 
     Wherever the word ‘about’ is employed herein, for example in the context of numbers or amounts, such as concentrations and/or doses of active ingredients, ages, etc., it will be appreciated that such variables are approximate and as such may vary by ±10%, for example ±5% and preferably ±2% (e.g. ±1%) from the numbers specified herein. In this respect, the term ‘about 10%’ means e.g. ±10% about the number 10, i.e. between 9% and 11%. 
     C21 has the advantage that it is capable of and protecting against pulmonary epithelial damage and dysfunction in patients, including SARS- and ARDS-like conditions that have been induced by a respiratory virus and, in doing so, abrogating and/or preventing the development of severe respiratory viral diseases as well as promoting accelerated resolution of such diseases. 
     C21 also has the advantage that it is more effective, has considerably less side effects, and/or is much safer, than current treatments of respiratory viral infections, and the (e.g. serious) diseases that are or may be caused thereby, such as those mentioned hereinbefore. 
     The uses and methods described herein may also have the advantage that, in the treatment of respiratory virus-induced tissue damage, they may be more convenient for the subject than, be more efficacious than, be less toxic than, have a broader range of activity than, be more potent than, produce fewer side effects than, or that they may have other useful pharmacological properties over, similar methods (treatments) known in the prior art, whether for use in the treatment of respiratory virus-induced tissue damage, viral infections and/or viral diseases generally, or otherwise. 
     The invention is illustrated by the following examples, in which  FIG. 1  shows the need for supplemental oxygen over time in a clinical trial conducted in COVID-19 patients that received either placebo or 100 mg C21 orally b.i.d over 7 days. 
     Example 1 
     Effect of C21 in In Vitro Human Airway Epithelial Cell Assay 
     The effect of C21 on E-cadherin expression was studied using the human disease model BioMAP® platform (fibrosis panel) with ELISA-based protein biomarker detection in a human small airway epithelial cell plus lung fibroblast (SAEMyoF) assay (a service provided by Eurofins DiscoverX Corporation, Fremont, Calif., USA). E-cadherin is a calcium-dependent epithelial cell adhesion molecule and has been suggested to contribute to disease progression (Gabrowska and Day,  Front. Biosci . ( Landmark Ed .), 17, 1948 (2014)), and also to play a critical role in viral infection at the level of host cell binding and viral entry into cells (see Hu et al,  Front. Cell. Infect. Microbiol.,  10, Article 74 (2020), https://doi.org/10.3389/fcimb.2020.00074). 
     It was found that C21 dose-dependently reduced E-cadherein levels. The relative expression level of E-cadherin (expressed as Log ratio C21/Vehicle control) was −0.0476 with 10 μM of C21. Lower concentrations of C21 (0.37, 1.1 and 3.3 μM) did not reduce E-cadherin. 
     Example 2 
     In Vitro Cell Assay I 
     SARS virus cellular entry and/or replication is studied in vitro using appropriate methods described in the scientific literature, for example as described in Struck et al,  Antioviral Research,  94, 288 (2012), Walls et al,  Cell,  180, 1 (2020) and/or Zhou et al,  Nature,  579, 270 (2020). Other relevant/equivalent cell types (including alveolar epithelial type II (ATII) cells) and methods for measuring viral cellular entry and/or replication may also be used. Prior to and/or during exposure of cells to different amounts of virus, the cells are incubated with different concentration (e.g. from 0.1 nM to 1 mM) of C21 for different periods of time. 
     Example 3 
     In Vitro Human IPF Lung Tissue Assay 
     Experiments were performed by FibroFind Limited, Gateshead, United Kingdom. 
     Lung tissue extracted from living human patients (Precision Cut Lung Slices (PCLuS) diseased with idiopathic pulmonary fibrosis) was subjected to acute injury, having been explanted/collected at the time of lung transplantation. 
     PCLuS were rested for 48 hours to allow the post-slicing stress period to elapse before experiments begin. PCLuS were cultured in the presence or absence of 10 μM of the Alk5 inhibitor SB-525334 (Sigma, #S8822), a potent activin receptor-like kinase (ALK5)/type I TGFβ-receptor kinase inhibitor. In addition, in separate wells, PCLuS were cultured in the presence of C21 at different concentrations (0.01, 0.1, 1 and/or 10 μM). 
     PCLuS culture supernatant (n=4-6 per group) were collected daily and snap frozen for quantification of levels of the pro-fibrotic growth factor transforming growth factor-β1 (TGF-β1)) at 48, 96 and 144 hours using R&amp;D Duoset ELISA kits and/or sandwich ELISA (from e.g. Abcam and/or RayBioTech). 
     It was found that C21 dose-dependently reduced the release of TGF-β1 from the PCLuS (i.e. tissue from the human respiratory tract subjected to acute injury) at both 96 and 144 hours, with maximum inhibitory effects of C21 being 49% at 96 hours and 61% at 144 hours. The inhibitory effects of C21 were greater than those after treatment with the Alk5 inhibitor used as a positive control. 
     Example 4 
     Clinical Trial Evaluating Safety and Efficacy of C21 in Patients with SARS-CoV-2 Virus Infection (I) 
     This is a clinical study evaluating the safety and effectiveness of C21 (100-400 mg, including 200 mg, daily). 
     The key objectives/endpoints of the study are to evaluate the safety and efficacy of C21 in participants with infection with SARS-CoV-2 virus. 
     Evaluation of efficacy of C21 is determined by determining inter alia:
         improvement in signs, symptoms, quality of life, manifestations and/or complications related to the disease, including fever, pulmonary and/or cardiac function, blood oxygen tension/hypoxia, cough, shortness of breath, multiple organ dysfunction syndrome (MODS), acute respiratory distress syndrome (ARDS), secondary pneumonia by other microorganisms and/or patient and/or clinician reported quality of life (QoL) outcome measures;   duration of hospital stay;   need for invasive and/or non-invasive ventilation;   surrogate markers of inflammation, immune response and/or infection, including radiography, ultra-sound, magnetic resonance imaging (MRI), computed tomography (CT) and/or other imaging modalities;   composite measures and/or ordinal scales that determine disease severity, for example time to clinical recovery and/or sequential organ failure assessment score (SOFA score);   viral titers and/or seroconversion;   morbidity and/or mortality;   and/or effects on relevant biomarkers, including those of epithelial damage/dysfunction (including MMP7, GDF15, CA125, CEA, CA19-9, cytokeratin 18 CCL18, Surfactant Protein-D and/or CYFRA-21-1), and biomarkers of systemic inflammation, immune response and/or infection, including C reactive protein, interleukin-6, tumor necrosis factor, blood leukocytes and/or antibodies.       

     Subjects for inclusion in the trial are those diagnosed with SARS-CoV-2 infection confirmed by polymerase chain reaction (PCR) test (or another relevant/equivalent test for this purpose), subjects that have been exposed to SARS-CoV-2, and/or symptomatic subjects that are suspected to have a SARS-CoV-2 infection. 
     Other inclusion criteria are defined in detail by the sponsor together with the investigators. Similarly, exclusion criteria are defined in detail by the sponsor together with the investigators, and may include subjects that inter alia:
         have participated in any other clinical trial of an experimental treatment for SARS-CoV-2 infection or COVID 19 disease;   require mechanical ventilation at the time of screening;   have a BMI of &gt;32 or &lt;18;   have a concurrent respiratory disease such as asthma, COPD or an interstitial lung disease;   have used medications known to chronically alter drug absorption or elimination processes within 30 days before the first dose administration;   have participated in a clinical study involving administration of an investigational drug or a marketed drug within the past 3 months;   have ailments that, in the opinion of the investigator, would interfere with the evaluation of the results or constitute a health risk for the study subject;   have serum hepatitis or are carriers of the hepatitis B surface antigen (HBsAg) or hepatitis C antibody;   have had positive result to the test for HIV antigens and/or antibodies;   are current or previous (&lt;6 months) smokers;   have a susceptibility to severe allergic reactions;   have donated blood or suffered a loss of a significant amount of blood within 2 months prior to the first study treatment administration;   have had a positive urine drug screen result at screening or randomly thereafter;   are pregnant women, or are women with childbearing potential not using regular contraceptives;   are men that are unwilling to use a condom for contraception when having sexual intercourse with a fertile woman, during the entire study and at least for 7 days after the last IMP intake.       

     Subjects are also asked to abstain from drinking alcoholic beverages for 12 hours before screening and during the study. 
     Instructions are given to take IMP fasted in the morning and 1 hour before intake of any food. The evening dose is ideally taken 2-4 hours of food fasting before intake and 1 hour after taking the drug. 
     The following medications are avoided in conjunction with C21 treatment:
         CYP3A4 inducers (e.g. rifampicin, phenytoin, St John&#39;s Wort)   CYP3A4 inhibitors (e.g. clarithromycin, ketoconazole, nefazodone, itraconazole, ritonavir)   medicines that are substrates of CYP1A2, CYP3A4 or CYP2C9 with a narrow therapeutic range   BCRP sensitive substrates (e.g. sulphasalazine, rosuvastatin)   H2 receptor antagonists and proton pump inhibitors       

     Example 5 
     Compassionate Uses 
     As an alternative to a clinical trial, the safety and efficacy of C21 (using similar criteria to those mentioned in Example 4 above), is determined by conducting early access to C21 on a compassionate-use basis such as a named (individual) patient program and/or an early access program on a cohort basis. 
     Example 6 
     Clinical Trial Evaluating Safety and Efficacy of C21 in Patients with SARS-CoV-2 Virus Infection (II) 
     Protocol 
     This was a randomised, double-blind, placebo-controlled, phase 2 trial conducted at multiple sites in India investigating the safety and efficacy of C21 in hospitalised subjects with COVID-19 infection not requiring mechanical ventilation. 
     The primary objective of the study was to investigate the efficacy of C21 200 mg daily dose (100 mg b.i.d.) on COVID-19 infection not requiring mechanical invasive or non-invasive ventilation. The secondary objectives were to evaluate the effect on inflammation and the safety profile of C21 at the same daily dose. Exploratory objectives include the investigation of a range of laboratory parameters as potential biomarkers of inflammation and viral load, following oral administration of that daily dose. 
     The primary endpoint of the trial was the change from baseline in measured values of C-reactive protein (CRP) after treatment (initial symptoms are not necessarily predictive of disease severity). 
     Secondary endpoints included changes from baseline in: 
     body temperature 
     IL-6 
     IL-10 
     TNF 
     CA125 
     Ferritin 
     as well as
     1) the number of subjects not in need of oxygen supply   2) the number of subjects not in need of mechanical invasive or non-invasive ventilation   3) the time until subjects were in need of mechanical invasive or non-invasive ventilation   4) the time subjects were on oxygen supply (for those not needing mechanical invasive or non-invasive ventilation)   5) numbers and severity of adverse events.   

     Blood samples were saved for potential future analyses of biomarkers reflecting inflammation and lung injury. 
     The trial was conducted on top of local standard of care for 7 days on approximately 100 subjects from multiple sites that have with COVID-19 infection. Subjects were randomised 1:1 to receive either standard of care+C21 (ca. N=50) or standard of care+placebo (ca. N=55). 
     All subjects were followed-up between 7 and 10 days after receiving the last investigational medicinal product (IMP) dose (visit or phone call, if recovering at home). 
     Inclusion criteria included the following:
     1) Written informed consent, consistent with ICH GCP R2 and local laws, obtained before the initiation of any trial related procedure.   2) Diagnosis of coronavirus (SARS-CoV-2) infection, confirmed by polymerase chain reaction (PCR) test within 4 days of Visit 1 with signs of an acute respiratory infection.   3) Age between 18 and 70 years inclusive.   4) CRP between 50 and 150 mg/L inclusive.   5) Admitted to a hospital or controlled facility (home quarantine was not deemed sufficient).   6) In the opinion of the Investigator, the subject was able to comply with the requirements of the protocol.   

     Exclusion criteria at the outset include one or more of the following:
         1) Any previous experimental treatment for COVID-19.   2) Need for mechanical invasive or non-invasive ventilation.   3) Concurrent respiratory disease such as chronic obstructive pulmonary disease, idiopathic pulmonary disease (IPF) and/or intermittent, persistent or more severe asthma requiring daily therapy or any subjects that have had an asthma flare requiring corticosteroids in the 4 weeks (28 days) prior to COVID-19 diagnosis.   4) Participation in any other interventional trial within 3 months prior to Visit 1.   5) Any of the following findings at Visit 1:
           positive results for hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCVAb) or human immunodeficiency virus 1+2 antigen/antibody (HIV 1+2 Ag/Ab); or   positive pregnancy test.   
           6) Clinically significant abnormal laboratory value at Visit 1 indicating a potential risk for the subject if enrolled in the trial as evaluated by the investigator.   7) Concurrent serious medical condition with special attention to cardiac or ophthalmic conditions (e.g. contraindications to cataract surgery), which in the opinion of the Investigator makes the subject inappropriate for this trial.   8) Malignancy within the past 3 years with the exception of in situ removal of basal cell carcinoma and cervical intraepithelial neoplasia grade I.   9) Treatment with any of the medications listed below within 1 week prior to Visit 1:
           strong Cytochrome p450 (CYP) 3A4 inducers (e.g. rifampicin, phenytoin, St. John&#39;s Wort, phenobarbital, rifabutin, carbamazepine, anti HIV drugs, barbituates); or   warfarin.   
           10) Pregnant or breast-feeding female subjects.   11) Female subjects of childbearing potential not willing to use prescribed contraceptive methods.   12) Male subjects not willing to use prescribed contraceptive methods.   13) Subjects known or suspected of not being able to comply with the trial protocol (e.g. due to alcoholism, drug dependency or psychological disorder).       

     A subject was withdrawn from IMP if any of the following occurred:
         Need for mechanical invasive or non-invasive ventilation   Discharge from the hospital/controlled facility   Major protocol deviations as defined by Sponsor.   Sponsor decision to stop the subject&#39;s participation in the trial; reasons included medical, safety, or regulatory issues, or other reasons consistent with applicable laws, regulations, and GCP.   It was the wish of the subject for any reason   The Investigator judged it necessary for medical reasons   Adverse events such as:
           Serious cardiovascular complications such as severe peripheral oedema or significant bradycardia indicating a potential risk for the subject as evaluated by the Investigator   Moderate to severe skin rashes as judged by the Investigator e.g. Stevens-Johnson syndrome and toxic epidermal necrolysis   
           Pregnancy       

     A subject was withdrawn from the trial if any of the following occurred:
         Enrolment in other clinical studies involving investigational products or enrolment in other types of clinical research judged not to be scientifically or medically compatible with this trial.   Disallowed treatment during the trial period   It was the wish of the subject for any reason   The Investigator judged it necessary for medical reasons   Adverse events   Lost to follow-up       

     IMP was delivered as 50 mg capsules (HPMC hard capsules) with a final composition as set out in Table 1 below. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
             
            
               
                   
                   
               
               
                   
                 Composition 
                   
               
            
           
           
               
               
               
            
               
                 Ingredient 
                 mg/capsule 
                 % w/w 
               
               
                   
               
            
           
           
               
               
               
            
               
                 C21 sodium salt 
                 52.8 
                 20.24 
               
               
                 mannitol (Pearlitol 50C) 
                 203.38 
                 77.93 
               
               
                 colloidal silicon dioxide (Aerosil 200) 
                 2.14 
                 0.82 
               
               
                 magnesium stearate (Ligamed MF-2-V) 
                 2.61 
                 1.00 
               
               
                   
               
            
           
         
       
     
     Capsules were packed in plastic container units with 28 capsules in each. Each unit contained either C21 or matching placebo (the same composition except that C21 was replaced with mannitol. 
     At the trial site, IMP was stored separately from normal clinic stocks in a securely locked area only accessible to authorised trial personnel. Labeling of the IMP was in the relevant local language (English) and was done in compliance with GMP (GMP 2003) and local regulatory requirements. 
     IMP was administered twice daily to the subjects for 7 days as follows:
         Morning dose: Two 50 mg capsules (100 mg C21 or placebo) to be taken with a glass of water after minimum 2 hours fasting   Afternoon/evening dose: Two 50 mg capsules (100 mg C21 or placebo) to be taken with a glass of water after minimum 2 hours fasting       

     Subjects were required not to eat anything for 1 hour after taking the IMP. 
     Concomitant medication was given if in accordance with local standards of care (which did develop and/or change during the course of the study as more was discovered and/or understood about the pathology of COVID-19). 
     Subjects were not allowed to take the following medications at least 1 week before Visit 1 and during the trial period:
         strong CYP3A4 inducers (e.g. rifampicin, phenytoin, St. John&#39;s Wort, phenobarbital, rifabutin, carbamazepine, anti HIV drugs, barbituates)   warfarin   experimental drugs       

     As the skilled person will appreciate, in view of the nature of a new disease like COVID-19, where understanding of its pathology changes rapidly and continuously, and with treatment often being administered on an emergency and/or intensive care basis, the above protocol may not have been strictly adhered to in every single patient. Following an analysis of the results reported below, it is been confirmed that all such data collected from enlisted patients regarding safety and efficacy of C21, when considered individually or as part of a cohort, is valid. 
     Results 
     A total of 106 hospitalised patients with a diagnosis of coronavirus SARS-CoV-2 infection (confirmed by polymerase chain reaction test) and signs of an acute respiratory infection, but not requiring mechanical ventilation were recruited. 
     The patients were randomised to receive C21 (100 mg b.i.d., n=51) or placebo (n=55) for 7 days on top of standard of care. The treatment groups were well balanced in relation to age, sex and concomitant medications. 
     As shown in  FIG. 1 , extended need for oxygen therapy was more frequent in the placebo group than in the C21 group. At Day 14, only one patient in the C21 group, compared to 11 patients in the placebo group, needed supplementary oxygen (p=0.003). This difference was already apparent at Day 8. 
     There were 4 deaths in the trial, one in the C21 group and 3 in the placebo group. All deaths occurred in patients with progressive respiratory insufficiency and need for mechanical ventilation. One more patient in the placebo group deteriorated and developed need for mechanical ventilation (4 events of mechanical ventilation in the placebo group vs 1 event in the C21 group). 
     There were 64 treatment-emergent adverse events reported by 60.8% of the patients in the C21 group and 90 events reported by 67.3% of the patients in the placebo group. Most events were mild, and no event in either group was classified as related to trial treatment by the investigators. 
     There were no significant differences between the placebo group and the C21 group with regard to levels of the circulating biomarkers of inflammation CRP, IL-6 and TNF. 
     Example 7 
     Non-Interventional, Retrospective, Multi-Center, Follow-Up Study Evaluating the Effect of C21 on Lung Pathology in Subjects Previously Hospitalised with COVID-19 and Enrolled in the Trial Described in Example 6 
     The purpose of this study was to evaluate the effect of C21 versus placebo as add on to standard of care (SoC) on lung pathology (including pulmonary fibrosis) as assessed by high-resolution computed tomography (HRCT), performed as part of normal clinical practice (hospital stay and follow-up) in subjects enrolled in the trial described in Example 6 above. 
     Data from HRCT provided further characterisation as to the long-term clinical effect of C21 (7 days treatment during the trial described in Example 6) in subjects with COVID-19. 
     Eligible subjects who provide written informed consent for the additional data to be collected are enrolled in this study. Beyond consenting, these subjects undergo no additional procedures or treatment as a result of being involved in this study. 
     Lung injury scores were assessed by an independent blinded (to treatment) radiologist experienced in HRCT scan reading at a national centre for thoracic disease in the UK. Scores were cumulative totals of conventional lung injury types commonly assessed by radiologists. Follow-up HRCT scans were recorded as part of local clinical practice at follow-up visits performed 90-170 days after the 7-day treatment period in the trial described in Example 6 above in subjects who had received either C21 or placebo on top of standard-of-care including steroids and the antiviral remdesivir. 
     The C21-treated subjects (n=17) displayed reduced pathological abnormalities compared to the placebo-treated subjects (n=16). In the C21 group, on average 10.3% of the lung was affected compared to 19.2% in the placebo group. The dominating radiological change was ground glass opacity, a pathological characteristic following viral respiratory infections. Although functional tests were not performed in this trial, it is known that reduced gas exchange is a common lung function abnormality in COVID-19 patients with an abnormal HRCT at 3 months. 
     There was generally very limited fibrosis in this cohort of patients. Regarding change from baseline to follow-up (C21 N=9, placebo N=4) in Total score, it decreased by 30.5 units in the C21 group and by 20.8 units in the placebo group (not statistically significant). Age was a risk factor for remaining HRCT pathology at follow-up. HRCT was normal for 8 (47%) patients in the C21 group and 9 (56%) patients in the placebo group (no differences were statistically significant). 
     In those patients with more severe initial disease, as defined as need for supplemental oxygen at the end of the 7-day treatment period, the difference between the treatment groups was more pronounced with patients treated with C21 (n=7) displaying pathological changes on average in 5.4% of the lungs compared to 20.9% in the placebo group (n=8) (no differences were statistically significant). 
     However, the results showed a nearly 50% reduction in lung injury in the C21 group compared with the placebo group suggesting that C21 has the potential to accelerate recovery after COVID-19.