EP4142731A1

EP4142731A1 - Treatment of pulmonary complications of coronavirus infections

Info

Publication number: EP4142731A1
Application number: EP21743056.0A
Authority: EP
Inventors: Iker NAVARRO
Original assignee: Noorik Biopharmaceuticals AG
Current assignee: Noorik Biopharmaceuticals AG
Priority date: 2020-04-28
Filing date: 2021-04-28
Publication date: 2023-03-08
Also published as: WO2021219671A1

Abstract

Methods and formulations are provided for the treatment and prevention of the pulmonary complications of coronavirus infections.

Description

TITLE OF INVENTION

Treatment of Pulmonary Complications of Coronavirus Infections

CROSS-REFERENCE TO RELATED APPLICATIONS Not Applicable

FIELD

This invention relates to the treatment and prevention of pulmonary complications resulting from an infection with a coronavirus, in particular hypoxemia, pulmonary edema, pneumonia, pulmonary hypertension, acute respiratory distress syndrome, post-infectious persistent sequelae and to related therapeutic and prophylactic formulations.

BACKGROUND

Viruses of the coronaviridae family, commonly referred to as a "coronavirus" or "coronaviruses", are responsible for about 15% of seasonal viral respiratory tract infections, which are mild, self-limiting conditions, sometimes referred to as the "common cold", and in which severe involvement of the lower respiratory tract is infrequent. However, infection with some strains of coronaviruses (i.e., MERS-CoV, SARS-CoV-1 or SARS-CoV-2) frequently results in a severe lower respiratory tract infection with pneumonitis, pneumonia, hypoxemia, respiratory insufficiency, respiratory failure, acute respiratory distress syndrome and the need for mechanical ventilation. Pulmonary complications of coronaviruses result in significant morbidity, mortality and disability. In addition, post-infectious sequelae may persist beyond the acute infection phase of the disease.

In the winter of 2019, a pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (or SARS-CoV-2) had resulted in several million people developing Coronavirus Disease 2019 (COVID-19). In only a few months, an unprecedented number of COVID-19 cases had developed, with many displaying severe pulmonary complications, respiratory insufficiency, respiratory failure, requiring mechanical ventilation and intensive care. Preliminary figures indicate that the mortality of COVID-19 is high. The SARS-CoV-2 virus, colloquially referred to as "coronavirus", is a new, positive-sense, single stranded RNA virus of the coronaviridae family and riboviria realm, believed to have both animal and human hosts and transmissible between humans. SARS-CoV-2 is related to SARS-CoV-1, the latter also a member of the coronaviridae family of viruses and at the center of a global outbreak ("SARS outbreak") between 2002-2004. In the SARS outbreak, 774 fatalities were recorded in about 8,098 confirmed cases (Centers for Disease Control, United States of America - SARS Website, htps://www.cdc.gov/sars/about/fs-SARS.pdf, accessed on April 26, 2020). MERS-CoV ("Middle East Respiratory Syndrome Coronavirus"), another member of the coronaviridae family, is notable for a limited outbreak originating in the Middle East ("MERS outbreak"), in which a high mortality was observed, with 858 fatalities reported in 2494 confirmed cases (34.4% mortality rate) (World Health Organization - MERS Website, htps://www.who.int/emergencies/mers-cov/en/, accessed on April 26, 2020). It is not well understood why only some strains of coronaviruses result in pulmonary complications and display a high mortality rate.

SARS-CoV-2, the coronavirus at the center of the pandemic of 2019-2020, has been reported to successfully replicate in human vascular endothelial cells, a process initiated through the binding of the SARS-CoV-2 spike protein to the angiotensin-converting-enzyme receptor 2 receptor (ACE2), a receptor expressed extensively in endothelial cells. Replication of SARS-CoV-2 in endothelial cells has been shown to result in significant vascular injury [1], [2], the latter a possible explanation for the relatively high frequency of severe adverse vascular events of thrombotic and ischemic nature observed in COVID-19 [3]

In patients developing COVID-19, early signs of respiratory insufficiency appear 6 to 7 days after the onset of general symptoms [4] Patients frequently present with hypoxemia (i.e., low oxygen tension in blood) and difficulty breathing [4], [5] Some patients with hypoxemia usually progress through a phase of pneumonitis, pulmonary edema, pneumonia and acute respiratory distress syndrome, the latter frequently requiring respiratory support, invasive mechanical ventilation and admission to the Intensive Care Unit [6]

Patients developing early respiratory symptoms associated with COVID-19 have been reported to have well-ventilated lungs on radiological examination despite presenting with significant hypoxemia [6]— [9] . This finding is of concern, as the severity of hypoxemia and respiratory symptoms cannot be entirely explained by the usually more benign radiological appearance of the lungs. This has led to the suggestion by some experts that an abnormal regulation of blood flow through the lungs may be responsible for impaired gas exchange: well ventilated areas of the lung amenable to gas exchange are inappropriately perfused by blood, and hence result in a condition called ventilation/perfusion mismatch [7], [10]. Furthermore, some experts have suggested that a state of vasodilation and loss of the ability of the lung to increase vascular resistance in the presence of hypoxemia results in shunting of the pulmonary circulation (i.e., increase in the proportion of blood circulating through the lungs but not participating in gas exchange), impairing the ability of the lung to exchange carbon dioxide and oxygen. In this respect, the same experts have advocated against the use of pulmonary vasodilators as patients with early respiratory problems do not have signs of overt pulmonary hypertension or elevated pulmonary pressures [7], [9] More recently, signs and symptoms of pulmonary hypertension have been reported in patients with acute COVID-19 and in survivors of COVID-19 with persistent post-infectious sequelae, the latter also referred to long-COVID or post-COVID. Signs of acute pulmonary hypertension in patients with acute COVID-19 or its post-infectious persistent sequelae have been reported with an array of diagnostic procedures such as echocardiography, radiological investigations or at the time of autopsy. These signs of acute pulmonary hypertension include increased estimated systolic pulmonary pressure [11]— [14], enlargement of the pulmonary artery [15], and right-heart functional and anatomical abnormalities [16]— [22]. Reports of rapidly progressing pulmonary hypertension in COVID- 19 survivors have also been reported [23] As such, there is an accumulating body of evidence indicating that acute pulmonary hypertension may be a condition inherent to COVID-19. The latter has prompted several experts to suggest that endothelin may participate in the vascular and respiratory complications of COVID-19 and that endothelin receptor antagonists may be of therapeutic benefit in this disease [24], [25], [34], [35], [26]- [33] To this effect, a clinical study of ambrisentan, an endothelin receptor antagonist

B administered at doses of 5 mg per day in combination with dapagliflozin has been initiated and is ongoing (https://clinicaltrials.gov/ct2/show/NCT04B9B246).

Endothelin, the most potent vasoconstrictor known to date [36], is an endogenous peptide hormone that has two natural receptors, an ETA receptor which mediates vasoconstriction and an ETB receptor which mediates vasodilation, diuresis and clearance of the endothelin [36], [37] By modifying vascular resistance and the cross-sectional area of small blood vessels, endothelin participates in the regulation of blood flow through the lungs. Endothelin receptor antagonists, such as ambrisentan, bosentan and macitentan are approved for the treatment of some forms of pulmonary arterial hypertension, a condition where pulmonary arterial pressure is increased [37], [38] Furthermore, the activity of endothelin in the respiratory tract is known to be increased in subjects with upper respiratory airway infections, such as with the respiratory syncytial virus [39] Experimental data suggest that endothelin may also participate in the regulation of the release of inflammatory mediators and the progression of respiratory complications, such as pulmonary edema and pneumonia [40]— [46] . Experimental blockade of the effects of endothelin reduces the secretion of Vascular Endothelial Growth Factor (VEGF) and lnterleukin-6 (IL-6), two cytokines believed to participate in viral-induced lung injury and alveolar leakage [44], [47] Also experimentally, blockade of the effects of endothelin with bosentan (ETA and ETB receptor blocker) and an endothelin receptor derived antisense homology box peptide in chicken infected with the H5N1 strain of influenza (also known as the "avian flu" or "bird flu") have resulted in improved animal survival, in an otherwise universally lethal condition [48], [49]

In this application, endothelin is proposed as key mediator of the vascular pulmonary abnormalities observed in patients with coronavirus infections and other viral infections. As described below, blockade of some of the effects of endothelin, in particular those vascular effects mediated by the ETA receptor and in patients with coronaviruses lead to an improvement of the pulmonary function and result in clinical benefit. SUMMARY

The inventors have found that the pulmonary complications of a coronavirus infection, in particular hypoxemia, can be prevented and treated by the administration of selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).

The inventors have further found that pulmonary edema associated with a coronavirus infection can be prevented and treated by administering selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).

The inventors have further found that pneumonia associated with a coronavirus infection can be prevented and treated by administering selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).

The inventors have further found that pulmonary hypertension associated with a coronavirus infection can be prevented and treated by administering selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).

The inventors have further found that acute respiratory distress syndrome associated with a coronavirus infection, can be prevented and treated by the administration of selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).

The inventors have further found that the post-infectious persistent sequelae associated with a coronavirus infection, can be prevented and treated by the administration of selective ETA antagonists in amounts that block the endothelin receptor subtype A (ETA) while not significantly blocking the endothelin receptor subtype B (ETB).

The inventors have further found that selective ETA antagonists interact with and antagonize the ETB receptor when administered at doses approved for the treatment of other conditions such as pulmonary arterial hypertension. In this regard, several endothelin receptor antagonists are approved for oral administration to treat pulmonary arterial hypertension, such as ambrisentan and other compounds discussed below. Some of these, including ambrisentan, are considered ETA selective antagonists. However, their systemic administration in approved dosage forms, notwithstanding their selectivity for the ETA receptor, results in plasma levels that are not ETA receptor selective and therefore are ineffective in preventing and treating pulmonary complications of a coronavirus infection.

In particular, the formulations and methods of the present invention are intended to treat or prevent conditions associated with coronavirus infections.

Achieving the benefits of the present invention requires new and improved formulations for selective ETA antagonists and new methods for their therapeutic use. Accordingly, one objective of the present invention is to provide novel formulations of ETA antagonists and to provide a new medical use of ETA antagonists.

DESCRIPTION OF INVENTION AND EMBODIMENTS

The present invention relates to a finding that maintaining relatively low blood plasma concentrations of selective ETA antagonists, such as ambrisentan in a preferred embodiment, is effective to treat or prevent the pulmonary complications of a coronavirus infection, in particular hypoxemia and pulmonary hypertension. By selectively blocking ETA receptors in pulmonary capillaries, the ETA antagonists reverse the vasoconstriction induced by endothelin, maintain capillary patency and increase the proportion of blood participating in gas exchange in the lung. The plasma concentrations of such ETA antagonists are preferably monitored because even selective ETA antagonists may partially antagonize ETB receptors when the concentration of the antagonist is too high. Because blocking the ETB receptor prevents vasodilation and clearance of endothelin, the clinical benefit provided by the ETA antagonist decreases or even disappears entirely if the effects of endothelin on the ETB receptors are also significantly antagonized. Furthermore, blocking the ETB receptor prevents the normal formation of urine by the kidney, may result in the retention of fluid and may represent a life-threatening adverse effect in patients in critical condition.

The present invention and its embodiments are discussed in greater detail below. Definitions:

"Acute respiratory distress syndrome" or "ARDS" refers to a type of respiratory insufficiency or failure of rapid onset. Symptoms and signs of acute respiratory distress syndrome include shortness of breath, tachypnea (rapid breathing), hypoxemia (low blood oxygen arterial tension) and others. Acute respiratory distress syndrome is hereafter referred to a syndrome fulfilling all diagnostic criteria of the Berlin ARDS classification [50] "Amount effective to improve hypoxemia", or "amount effective to improve oxygenation" and variations thereof, means that the amount of the administered compound will antagonize or block intra-pulmonary ETA receptors and other cellular components of the lung sufficiently to increase the amount of blood circulating through the lungs and participating in gas exchange, and resulting in an increase in oxygen tension in arterial blood (Pa02). The "amount effective" or "effective amount" refer to an amount effective, at dosages and for periods of time necessary, to achieve the desired therapeutic or prophylactic result. Such effective amounts can be expressed in daily doses of the endothelin receptor antagonist and/or in blood concentrations of the endothelin receptor antagonist, as is discussed herein. For hypoxemia, an effective amount is determined based on the amount necessary to achieve an increase in the oxygen tension in arterial blood (Pa02), an increase in the ratio between the oxygen tension in arterial blood and the inspired fraction of oxygen (Pa02/Fi02 ratio), or a decrease in the proportion of blood circulating through the lung and not participating in oxygen exchange (Qs/Qt or "shunt fraction"). For pulmonary edema, an effective amount is determined based on the amount necessary to achieve resolution of signs and symptoms of pulmonary edema (clinical or radiographical), an increase in lung compliance (e.g., decrease in Positive End-Expiratory Pressure [PEEP] required upon mechanical ventilation) or an improvement in blood oxygenation. For pneumonia, an effective amount is determined based on the amount necessary to achieve resolution of symptoms and radiological signs, an improvement in respiratory function or an increase in the odds of survival. For pulmonary hypertension, an effective amount is determined based on the amount necessary to reduce pulmonary arterial pressures (by echocardiographic or direct invasive measurement), pulmonary artery diameter, right-ventricular strain, right-ventricle size, lung diffusion capacity or a clinical benefit such as increased exercise tolerance (e.g., increased walking distance). For acute respiratory distress syndrome, an effective amount is determined based on the amount necessary to achieve an increase in the oxygen tension in arterial blood (Pa02), an increase in the ratio between the oxygen tension in arterial blood and the inspired fraction of oxygen (Pa02/Fi02 ratio), a decrease in the proportion of blood circulating through the lung and not participating in oxygen exchange (Qs/Qt or shunt fraction), a decrease in Positive End- Expiratory Pressure required upon mechanical ventilation, resolution of the radiological signs of acute respiratory distress syndrome, weaning from mechanical ventilation or respiratory support, or an increase in the odds of survival. For post-infectious sequelae, an effective amount is determined based on the amount necessary to achieve resolution of signs and symptoms, an improvement in respiratory function, an improvement in exercise capacity or an improvement in quality of life.

"Does not significantly antagonize endothelin receptor type B" means that the administered compound does not antagonize the ETB receptor at all or to such an extent that the vasodilatory effect of the ETA receptor antagonism is not compromised or adverse renal effects, such as fluid retention and which are secondary to an antagonism of the ETB receptor, are not observed in a patient. When the ETB receptor is significantly antagonized, the increase in pulmonary capillary flow caused by antagonizing the ETA receptor is reduced, not observed, or even counteracted completely. Such antagonism of the ETB receptor can be established by determining the concentration of endothelin in the blood. When the ETB receptor is not blocked by the antagonist, the endothelin concentration will be similar to before treatment. When the ETB receptor is fully antagonized, the endothelin concentration after treatment with the antagonist will be higher than the level measured before treatment. With preferential ETA receptor blockade, the endothelin concentration in the blood is at most 150% of the endothelin concentration before treatment, more preferably at most 130%, even more preferably at most 120%, and even more preferably at most 110% of the endothelin concentration before treatment. Most preferably, the endothelin concentration is the same in the blood after treatment with the selective ETA antagonist. When the ETB receptor is significantly antagonized in a patient, the incidence and severity of adverse renal effects such as weight gain, retention of fluid and/or pulmonary edema are increased.

"Improved oxygenation" and variations thereof such as "improvement in arterial oxygen tension", means that a subject who receives the compounds and formulations according to the present invention shows an increase in the total content of oxygen in blood (Pa02), an increase in the ratio between the oxygen tension in arterial blood and the inspired fraction of oxygen (Pa02/Fi02), or a decrease in the proportion of blood circulating through the lung and not participating in oxygen exchange (Qs/Qt or "shunt fraction"). Such improvement may be associated with beneficial changes, including, for example, decreased incidence and severity of pulmonary edema, a decreased incidence and severity of pneumonia, a decrease in pulmonary hypertension, a decrease in pulmonary vascular resistance, resolution of the signs and symptoms of acute respiratory distress syndrome or a decreased incidence of acute respiratory distress syndrome. For example, patients treated according to the present invention may show an increase in arterial blood oxygen tension (Pa02) as determined by arterial gas analysis of at least 10%, preferably at least 20%, in the ratio between the oxygen tension in arterial blood and the inspired fraction of oxygen (Pa02/Fi02) above at least 200 mmHg, preferably at least 300 mmHg, an increase in the ratio between the oxygen tension in arterial blood and the inspired fraction of oxygen (Pa02/Fi02 ratio) of at least 10%, preferably at least 20%, or a decrease in the proportion of blood circulating through the lung and not participating in oxygen exchange (Qs/Qt or shunt fraction) to at most 20%, preferably at most 10% and most preferably at most 5%.

"Individual" or "subject" or "patient" is a mammal. Mammals include, but are not limited to, domesticated animals (for example, cows, sheep, cats, dogs, and horses), primates (for example, humans and non-human primates such as monkeys), rabbits, and rodents (for example, mice and rats). In preferred embodiments, the individual or subject is a human being. "Coronavirus infection" is an infection of a subject with a virus of the coronaviridae family, whether confirmed by laboratory testing or by clinical suspicion.

"Viral infection" is an infection of a subject with a virus, whether confirmed by laboratory testing or by clinical suspicion. Viral infection further refers to infections of the upper and lower respiratory tract. Viral infections of the upper and lower respiratory tracts are commonly caused by adenoviruses, influenza viruses, respiratory syncytial viruses, coronaviruses, parainfluenza viruses, among others.

"Liquid composition for parenteral administration" or "liquid formulation for parenteral administration" refers to a preparation which is suitable for intravenous, intraperitoneal, subcutaneous and/or intramuscular administration and in such form as to permit the biological activity of the active ingredient such as an endothelin receptor antagonist, contained therein to be effective, and which contains no additional components which are unacceptably toxic to a subject to which the formulation would be administered. These terms include both compositions that can be directly administered to a subject as well as compositions that need dilution or reconstitution into a conventional parenteral carrier solution. The liquid compositions for intravenous, intraperitoneal, subcutaneous or intramuscular administration may have the same ingredients in the same amounts, but compositions with different ingredients and/or different amounts also are contemplated.

"Liquid composition for oral administration" or "liquid formulation for oral administration" refers to a preparation which is suitable for oral administration and in such form as to permit the biological activity of the active ingredient such as an endothelin receptor antagonist, contained therein to be effective, and which contains no additional components which are unacceptably toxic to a subject to which the formulation would be administered. These terms include both compositions that can be directly administered to a subject as well as compositions that need dilution or reconstitution into a conventional oral carrier solution. Examples of such liquid compositions include oral solutions and oral sprays.

"Pneumonitis" refers to a general inflammation (i.e., the presence of inflammatory cells) of the lung, resulting from a coronavirus infection. "Pneumonia" refers to the presence of an exudate of inflammatory cells, fluid, other cells or debris in the alveolar space of some regions of the lungs, and this exudate is susceptible to infection with other pathogens.

"Pulmonary complications of a coronavirus infection" or "Pulmonary complications associated to a coronavirus infection" refers to the development of adverse changes in or impairment of normal respiratory and/or pulmonary function in a subject suspected to have an infection with a coronavirus. Such complications include hypoxemia, respiratory insufficiency, respiratory failure, pulmonary edema, pneumonia, pulmonary hypertension, acute respiratory distress syndrome and post-infectious persistent sequelae. Pulmonary complications are usually diagnosed by the reporting of symptoms by the subject, the observation of radiological or functional changes in respiratory function or a combination thereof.

"Pulmonary edema" refers to the abnormal accumulation of fluid in the interstitial or alveolar spaces of the lung.

"Pulmonary Hypertension" refers to an increase in resistance to blood flow in the pulmonary circulation and resulting in right-heart strain, an increase in pulmonary arterial pressures or an increase in pulmonary artery diameter. Signs of pulmonary hypertension may be associated occasionally with symptoms of respiratory insufficiency, such as limited exercise capacity or hypoxemia.

"Pulmonary Arterial Hypertension" refers to a distinct subgroup of forms of pulmonary hypertension. Forms of pulmonary hypertension belonging to the pulmonary arterial hypertension subgroup (Group 1) are those classified by the World Health Organization (WHO) as forms of pulmonary hypertension which are idiopathic, heritable, drug and toxin- induced, as well as forms associated with connective tissue disease, congenital heart disease, human immunodeficiency infection virus infection, portal hypertension, congenital heart disease and schistosomiasis [51].

"Post-infectious persistent sequelae" refers to signs and symptoms occurring in the convalescent period following an infection with a coronavirus or other viral infection, and includes signs and symptoms of fatigue, limited exercise capacity, impaired lung diffusion capacity, headaches, shortness of breath, anosmia (loss of smell), muscle weakness, low fever, cognitive dysfunction, affective symptoms and other neurologic or psychiatric symptoms. In case the sequelae are secondary to an infection with SARS-CoV-2, this group of sequelae is referred to as "Post-COVID" or "Long-COVID". Post-infectious persistent sequelae may include the persistence of symptoms which were present during the acute phase of the infection with the coronavirus, or the onset of new symptoms known to occur after the acute coronavirus infection.

"Shunt Fraction", "Shunting" or "Right-to-Left Shunt" and variations thereof, refers to the hemodynamic phenomenon where a proportion of blood flowing through the lung does not participate in gas exchange. Shunting is a type of ventilation/perfusion mismatch.

"Substantially continuous" means that the administration of the compounds and formulations according to the present invention may be constant or intermittent so long as the indicated blood levels of the ETA inhibitor are maintained, or the intended benefit is obtained.

"Treatment" (and variations thereof such as "treat" or "treating") as well as "prevention" (and variants thereof such as "prevent" or "preventing") refer to clinical intervention in an attempt to alter the natural course of the pathological condition of the individual being treated and can be performed either for prophylaxis or during the course of clinical pathology. Desirable effects of treatment include, but are not limited to, preventing occurrence or recurrence of disease, alleviation of symptoms, diminishment of any direct or indirect pathological consequences of the disease, decreasing the rate of disease progression, amelioration or palliation of the disease state, and remission or improved prognosis.

"Ventilation/Perfusion Mismatch", also referred to as V/Q defects, is a condition in which not all areas of the lung are adequately ventilated (i.e., receive oxygen through the respiratory airway) or perfused (i.e., receive adequate blood flow), resulting in impaired gas exchange, with the following most common variants: areas of the lung that are ventilated, but not perfused, or areas of the lung that are perfused, but not ventilated. It is quantified by the V/Q ratio (volume of air ventilation per minute divided by the cardiac output per minute).

TREATMENT OF PULMONARY COMPLICATIONS OF A CORONAVIRUS INFECTION

Endothelin plays a central role in the development of pulmonary complications in patients with viral respiratory infections, including coronavirus infections. The activity of endothelin, a potent regulator of the pulmonary circulation, is increased in the lungs in the context of viral respiratory infection [43], [46], [52] and hypoxemia. Hypoxemia, is frequently associated with viral respiratory infections, and is per se a potent pulmonary vasoconstrictor, resulting in an increase in pulmonary vascular resistance and pulmonary pressures [53], [54] This increased activity of endothelin on the pulmonary circulation results in regional alterations of blood flow in the lungs. These effects of endothelin are predominantly mediated by the activation of ETA receptors by endothelin in the lung capillaries [53], [55], resulting in regional vasoconstriction, a ventilation/perfusion mismatch [10], worsening of hypoxemia and pulmonary hypertension. Other effects of endothelin in the context of respiratory viral infections and hypoxemia, include the accumulation of fluid in the alveolar space, the latter resulting in pulmonary edema [45], [56] The accumulation of fluid in the alveolar space and the further exudation of inflammatory cells and debris results in the development of pneumonia. Once a critical proportion of the lungs is affected, ventilation is significantly compromised, further aggravating hypoxemia and resulting in the onset of acute respiratory distress syndrome, the latter a condition independently associated with higher concentrations of endothelin in blood [57]— [59] . By blocking the effects of endothelin on the ETA receptor, the vascular alterations, in particular the regional vasoconstriction of certain areas of the lung, the increase in pulmonary pressures and the progression to progressive respiratory complications of the infection are treated or prevented.

Various endothelin receptor antagonists are known, including selective ETA antagonists, such as, for example, sitaxentan, ambrisentan, atrasentan, BQ-123, zibotentan, bosentan, macitentan, tezosentan and darusentan. Preferred endothelin receptor antagonists are

IB sitaxentan, ambrisentan, atrasentan, bosentan and macitentan. More preferred endothelin receptor antagonists are atrasentan, zibotentan and ambrisentan. Even more preferred endothelin receptor antagonists are atrasentan and ambrisentan. The most preferred antagonist is ambrisentan. None of these are approved for the treatment of the pulmonary complications of a coronavirus infection. Instead, some of these are approved for the treatment of some forms of pulmonary arterial hypertension.

Contrary to the methods and formulations of the present invention, the approved dosage and formulations of endothelin receptor antagonists for the treatment of pulmonary arterial hypertension create plasma levels of the endothelin receptor antagonist that significantly antagonize the effects of endothelin on the ETB receptors as well as the effects of endothelin on the ETA receptors in subjects with a coronavirus infection and the pulmonary complications specified above, thereby causing no increase in pulmonary capillary flow or decreased rather than increased pulmonary capillary flow. For example, ambrisentan, sold under the product name of Letairis in the US and Volibris in Europe, was approved for daily oral administration at a dosage strength of 5 mg and 10 mg. Plasma levels following one-time administration of Letairis^* in patients often reach 700 ng/ml, and generally are found in the range of about 350 ng/ml or 670 ng/ml for the 5 mg and 10 mg doses, respectively. Such concentrations are too high to be effective in treating the pulmonary complications of a coronavirus infection, as they are not selective to the ETA receptor and block both the ETA and ETB receptors, and in fact are counterproductive because they contribute to the decrease in pulmonary capillary flow, through blockade of the ETB receptor, and hence may aggravate hypoxemia and the ventilation/perfusion mismatch. Furthermore, high concentrations of the endothelin antagonist may lead to the blockade of ETB receptor sites in other organs outside the lung and may induce fluid retention by the kidney. Fluid retention by the kidney is an undesired effect in subjects prone to develop pulmonary edema, acute respiratory distress syndrome or are under intensive care.

Moreover, subjects with hypoxemia and other pulmonary complications of a coronavirus infection have frequently difficulties to swallow solids, in particular when the subject has difficulty breathing, is under oxygen supplementation, the upper airway has been intubated and in the elderly. As such, solid formulations of the drugs may be difficult to swallow and may lead to low compliance with the treatment regimen, unlike liquid formulations that are easier to swallow, may be administered parenterally and provide for buccal absorption of the drug.

For all of these reasons, when administered at the approved dosage form and strength, Letairis (ambrisentan) and other compounds approved to treat pulmonary arterial hypertension are not effective to treat the pulmonary complications of a coronavirus infection. Moreover, use of approved pulmonary arterial hypertension therapies to treat pulmonary complications of a coronavirus infection may be detrimental in restoring an improved oxygenation and may increase the incidence of renal adverse effects.

Accordingly, the methods and formulations of the present invention contemplate the use of ETA antagonists to achieve much lower blood concentrations than are commonly used for approved therapies for pulmonary arterial hypertension. In one embodiment of the present invention oral routes of administration, particularly solutions, sprays, drops, oral dispersible tablets, dispersible oral films, oral films and powders, are suitable for the various indications described in this application. In addition, preferred embodiments of the present invention also involve parenteral routes of administration, particularly intravenous, subcutaneous and transdermal.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary complications of a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary complications of a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary complications of a coronavirus infection wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of pulmonary complications of a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing pulmonary complications of a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent pulmonary complications of a coronavirus infection wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of hypoxemia associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating hypoxemia associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from hypoxemia associated with a coronavirus infection wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary edema associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary edema associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary edema associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pneumonia associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pneumonia associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pneumonia associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary hypertension associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary hypertension associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary hypertension associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of pulmonary hypertension associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing pulmonary hypertension associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent pulmonary hypertension associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of acute respiratory distress syndrome associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating acute respiratory distress syndrome associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from acute respiratory distress syndrome associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of acute respiratory distress syndrome associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing acute respiratory distress syndrome associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent acute respiratory distress syndrome associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of post-infectious persistent sequelae associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating post-infectious persistent sequelae associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from post- infectious persistent sequelae associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of post-infectious persistent sequelae associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing post-infectious persistent sequelae associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent post-infectious persistent sequelae associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary complications of a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary complications of a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary complications of a viral infection wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of pulmonary complications of a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing pulmonary complications of a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent pulmonary complications of a viral infection wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of hypoxemia associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating hypoxemia associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from hypoxemia associated with a viral infection wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary edema associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary edema associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary edema associated with a viral infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pneumonia associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pneumonia associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pneumonia associated with a viral infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary hypertension associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary hypertension associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary hypertension associated with a viral infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of pulmonary hypertension associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing pulmonary hypertension associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent pulmonary hypertension associated with a viral infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of acute respiratory distress syndrome associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating acute respiratory distress syndrome associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from acute respiratory distress syndrome associated with a viral infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of acute respiratory distress syndrome associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing acute respiratory distress syndrome associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent acute respiratory distress syndrome associated with a viral infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of post-infectious persistent sequelae associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating post-infectious persistent sequelae associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from post- infectious persistent sequelae associated with a viral infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of post-infectious persistent sequelae associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing post-infectious persistent sequelae associated with a viral infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent post- infectious persistent sequelae associated with a viral infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of hypoxemia, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating hypoxemia, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from hypoxemia wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary edema, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary edema, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary edema comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pneumonia, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pneumonia, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pneumonia comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary hypertension, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary hypertension, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary hypertension comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary arterial hypertension, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary arterial hypertension, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary arterial hypertension comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of hypoxic pulmonary vasoconstriction, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating hypoxic pulmonary vasoconstriction, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from hypoxic pulmonary vasoconstriction comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of high-altitude pulmonary edema, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating high-altitude pulmonary edema, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from high-altitude pulmonary edema comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of high-altitude sickness, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in prophylactically treating high-altitude sickness, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for prophylactically treating a subject suffering from high-altitude sickness comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of pulmonary fibrosis, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating pulmonary fibrosis, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from pulmonary fibrosis comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of acute lung injury, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating acute lung injury, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from acute lung injury comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the treatment of acute respiratory distress syndrome, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in treating acute respiratory distress syndrome, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject suffering from acute respiratory distress syndrome comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

In a preferred embodiment, the invention pertains to the use of ambrisentan or a liquid composition comprising ambrisentan in the prophylactic treatment of acute respiratory distress syndrome, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. The invention hence pertains to ambrisentan for use in preventing acute respiratory distress syndrome, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml. Further, the invention provides a method for treating a subject to prevent acute respiratory distress syndrome comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

The above embodiments also apply to zibotentan and atrasentan, and their individual embodiments are also included.

THERAPEUTIC LEVELS OF ETA ANTAGONIST:

In a preferred embodiment of the present invention, the ETA antagonist is ambrisentan. For purposes of the present invention, ambrisentan is administered to a treated subject such that the plasma levels of that compound preferably are maintained below about 20 ng/ml, preferably below about 10 ng/ml, more preferably below about 5 ng/ml, and most preferably below about 2 ng/ml, and generally, the plasma level of ambrisentan is at least 0.001 ng/ml, preferably at least 0.01 ng/ and most preferably at least 0.1 ng/ml. The said plasma levels of ambrisentan refer to the overall ambrisentan concentration in the blood plasma, which include both the ambrisentan bound to proteins present in the blood and the free, unbound ambrisentan present in the blood. The plasma levels or concentration of both bound and unbound ambrisentan can be determined using conventional techniques.

In a further embodiment, ambrisentan is administered to a treated subject such that the plasma levels of unbound ambrisentan (i.e., not bound to protein) are at most 0.1 ng/ml, preferably at most 0.08 ng/ml, more preferably at most 0.06 ng/ml, and most preferably at most 0.05 ng/ml, and generally at least 0.00001 ng/ml, preferably at least 0.0001 ng/ml, and most preferably at least 0.001 ng/ml. The plasma levels or concentration of the free ambrisentan in the blood plasma can be determined by separating the ambrisentan bound to protein and determining the ambrisentan concentration using conventional analytical techniques.

ADMINISTRATION PROTOCOLS:

It is contemplated that ETA antagonists according to the present invention will be administered for a period of time in which such administration provides clinical benefit. In the case the ETA antagonist, in particular ambrisentan, is used to treat the pulmonary complications of a coronavirus infection which is of a temporary nature, the ETA antagonist will be administered for a period of time of up to about seven days, preferably up to about fourteen days, and most preferably for about twenty-eight days. In the case the ETA antagonist, in particular ambrisentan, is used to treat the post-infectious persistent sequelae of a coronavirus infection, the ETA antagonist will be administered for a period of time in which such administration provides clinical benefit. The administration of the ETA antagonist, when administered intravenously, will be substantially continuous.

However, a physician may choose to administer the ETA antagonist in a repeated cycle of, for example, four days, with one or more intervening days in which the ETA antagonist is not administered.

In the case the ETA antagonist, in particular ambrisentan, is used to treat pulmonary complications of a coronavirus infection, specifically hypoxemia, pulmonary edema, pneumonia, pulmonary hypertension, acute respiratory distress syndrome, or the post- infectious persistent sequelae, the ETA antagonist will be administered for a prolonged period of time on a daily basis or less often. The prolonged period can be the period up to the patient dies.

In one embodiment of the invention, the frequency of administration of the ETA antagonist, preferably ambrisentan, is more than once a day, more preferably twice a day, and most preferably three times a day. In this way, the concentration of the antagonist in the blood plasma does not exceed 20 ng/mL at any given time, and the actual plasma concentration of the ETA antagonist, preferably ambrisentan, remains sufficiently high to maintain an increase in pulmonary capillary flow.

In one embodiment, ambrisentan is administered to a subject through an oral solution. The frequency of administration is as described above. Further, the oral spray can be used for all indications mentioned in this specification.

In one embodiment, ambrisentan is administered to a subject through an oral spray using a spraying device. The oral spray may be an oral solution or a parenteral solution as described below. The invention further pertains to a spraying device comprising an oral spray device wherein the device is capable of spraying the oral solution, in particular the

BO spraying of about 25 to 120 mI of oral solution per spray device actuation. An example of such a spray device is a spray pump. Depending on the subject and the severity of the disease one or more actuations of the spray are necessary per treatment, preferably between 1 and 5 spray actuations. The frequency of administration is as described above. Further, the oral spray can be used for all indications mentioned in this specification.

FORMULATIONS:

Formulations suitable for use in the aforementioned treatments and indications are formulations that upon administration enable the maintenance of the blood plasma level of the ETA antagonist, preferably ambrisentan, below 20 ng/ml. The inventors have found that formulations that are administered orally are suitable, in particular formulations allowing the ETA antagonist, preferably ambrisentan, to be released in the patient's mouth or gastrointestinal tract. Examples of such formulations include oral solutions (OS), orally disintegrating films (ODF), orally disintegrating tablets (ODT), oral sprays and powders. Doses that are not administered in solid form have the additional advantage of being appropriate for subjects who have difficulty in swallowing solids, such as subjects suffering from a neurological deficit, neuropsychiatric impairment, endotracheal intubation, mechanical ventilation or older subjects. Oral administration in the form of solution has the advantage that the antagonist is also absorbed in a shorter period of time than alternative administration methods because of absorption in the mouth mucosa or gastrointestinal tract, and the desired blood concentration can be reached more readily and more effectively than with solid oral formulations. Additionally, doses administered in the form of oral solutions such as drops or oral sprays can be adjusted in a simple manner, which may be necessary in view of the metabolic and functional characteristics of the subject.

In one embodiment, the formulation is a parenteral formulation. The invention further pertains to a patch comprising the ETA antagonist, preferably ambrisentan.

The invention further pertains to an oral solution. The oral solution of the invention comprises a solvent and an ETA, preferably ambrisentan. The solvent can be any solvent known in the art that can be suitably used in oral solutions of the invention. Examples of solvents include water, alcohols such as ethanol, glycerin, polyethylene glycol such as PEG300, PEG400 and PEG600; propylene glycol, N- methyl-2-pyrrolidone, and combinations of two or more of these solvents. Of these solvents water, ethanol, propylene glycol and polyethylene glycol or combinations comprising predominantly any one of these solvents are preferred. In another preferred embodiment, the composition of the invention does not contain water as solvent, and more preferably the composition is free from water. In a preferred embodiment, the solvent comprises ethanol and propylene glycol.

In one embodiment of the invention, the oral solution comprises the solvent in an amount of at most 99.999 % by weight (wt%), based on the total weight of the oral solution. Preferably, the solvent is present in an amount of at most 99.995 wt%, more preferably at most 99.99 wt%, and most preferably at most 99.985 wt%, and preferably at least 99 wt%, more preferably at least 99.5 wt%, even more preferably at least 99.8 wt%, even more preferably at least 99.9 wt% and most preferably at least 99.95 wt%, based on the total weight of the oral solution.

In one embodiment of the invention, the oral solution comprises ambrisentan in an amount of at most 1 % by weight (wt%), based on the total weight of the oral solution. Preferably, ambrisentan is present in an amount of at most 0.5 wt%, more preferably at most 0.2 wt%, even more preferably at most 0.1 wt% and most preferably at most 0.05 wt%, and preferably at least 0.0001 wt%, more preferably at least 0.0005 wt%, even more preferably at least 0.001 wt% and most preferably at least 0.0015 wt%, based on the total weight of the oral solution.

The oral solution of the invention may further comprise OS excipients. The OS excipients may be any excipient known in the art that can be suitably used in oral solutions of the invention. Examples of such OS excipients include surfactants such as sodium dodecyl sulfate, sodium lauryl sulfate, polyoxyethylene sorbitan fatty acids (sold under tradename Tween^®), sorbitan fatty acid esters (sold under tradename Span^®) and polyoxyethylene stearates; rheology modifiers such as cellulose derivatives, alginic acid and polyvinyl pyrrolidone; preservatives such as boric acid, borate salts, sorbic acid, sorbate salts and phenolics; anti-oxidants such as sodium formaldehyde sulphoxylate, butylated hydroxyanisol and butylated hydroxytoluene (BHT); flavors such as mint, licorice and sucralose; sweetening agents such as fructose, mannitol, sorbitol, aspartame and saccharose; saliva stimulating agents such as citric acid, malic acid, tartaric acid, ascorbic acid and lactic acid; and coloring agents such as titanium dioxide, amaranth, sunset yellow and red iron oxide.

In one embodiment of the invention, the oral solution comprises the OS excipient in an amount of at most 15 % by weight (wt%), based on the total weight of the oral solution. Preferably, the OS excipient is present in an amount of at most 10 wt%, more preferably at most 8 wt%, even more preferably at most 7 wt% and most preferably at most 5 wt%, and preferably at least 0.01 wt%, more preferably at least 0.1 wt%, even more preferably at least 0.5 wt% and most preferably at least 1 wt%, based on the total weight of the oral solution.

Typically, the total amount of the endothelin receptor antagonist, the solvent and the OS excipients (when present) add up to 100 wt% in the oral solution of the invention.

The invention further pertains to an oral solution administered with the aid of a spray pump.

The invention further pertains to orally disintegrating films, also referred to as "ODF" or "orodispersible films". The orally disintegrating film of the invention comprises a water- soluble polymer and an ETA, preferably ambrisentan.

The water-soluble polymer can be any polymer known in the art that can be suitably used in ODFs of the invention. Examples of such polymers include natural polymers such as starch, polymerized rosin, pullulan, sodium alginate, pectin, carrageenan, chitosan, gelatin and maltodextrins; and synthetic polymers such as polyvinyl alcohol (PVA), polyethylene oxide (PEO), hydroxypropyl methyl cellulose (HPMC), sodium carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP) and hydroxypropyl cellulose (HPC).

In one embodiment of the invention, the ODF comprises the water-soluble polymer in an amount of at most 99.999 % by weight (wt%), based on the total weight of the ODF.

BB Preferably, the polymer is present in an amount of at most 99.995 wt%, more preferably at most 99.99 wt%, and most preferably at most 99.985 wt%, and preferably at least 99 wt%, more preferably at least 99.5 wt%, even more preferably at least 99.8 wt%, even more preferably at least 99.9 wt% and most preferably at least 99.95 wt%, based on the total weight of the ODF.

In one embodiment of the invention, the ODF comprises ambrisentan in an amount of at most 1 % by weight (wt%), based on the total weight of the ODF. Preferably, ambrisentan is present in an amount of at most 0.5 wt%, more preferably at most 0.2 wt%, even more preferably at most 0.1 wt% and most preferably at most 0.05 wt%, and preferably at least 0.0001 wt%, more preferably at least 0.0005 wt%, even more preferably at least 0.001 wt% and most preferably at least 0.0015 wt%, based on the total weight of the ODF.

The ODF of the invention may further comprise a plasticizer. The plasticizer can be any plasticizer known in the art that can be suitably used in ODFs of the invention. Examples of such plasticizers include polyethylene glycol, glycerol, diethyl phthalate, triethyl citrate and tributyl citrate.

In one embodiment of the invention, the ODF comprises the plasticizer in an amount of at most 15 % by weight (wt%), based on the total weight of the ODF. Preferably, the plasticizer is present in an amount of at most 10 wt%, more preferably at most 8 wt%, even more preferably at most 7 wt% and most preferably at most 5 wt%, and preferably at least 0.01 wt%, more preferably at least 0.1 wt%, even more preferably at least 0.5 wt% and most preferably at least 1 wt%, based on the total weight of the ODF.

The ODF of the invention may further comprise a surfactant. The surfactant can be any surfactant known in the art that can be suitably used in ODFs of the invention. Examples of such surfactants include benzalkonium chloride, sorbitan-based surfactants such as Tween^® 20 and Tween 80, block-copolymer of polyethylene glycol and polypropylene glycol such as Poloxamer^® 407 and sodium lauryl sulfate.

In one embodiment of the invention, the ODF comprises the surfactant in an amount of at most 15 % by weight (wt%), based on the total weight of the ODF. Preferably, the surfactant is present in an amount of at most 10 wt%, more preferably at most 8 wt%, even more preferably at most 7 wt% and most preferably at most 5 wt%, and preferably at least 0.01 wt%, more preferably at least 0.1 wt%, even more preferably at least 0.5 wt% and most preferably at least 1 wt%, based on the total weight of the ODF.

The ODF of the invention may further comprise ODF excipients. The ODF excipients may be any excipient known in the art that can be suitably used in ODFs of the invention. Examples of such ODF excipients include flavors such as mint, licorice and sucralose; sweetening agents such as fructose, mannitol, sorbitol, aspartame and saccharose; saliva stimulating agents such as citric acid, malic acid, tartaric acid, ascorbic acid and lactic acid; and coloring agents such as titanium dioxide.

In one embodiment of the invention, the ODF comprises the ODF excipient in an amount of at most 15 % by weight (wt%), based on the total weight of the ODF. Preferably, the ODF excipient is present in an amount of at most 10 wt%, more preferably at most 8 wt%, even more preferably at most 7 wt% and most preferably at most 5 wt%, and preferably at least 0.01 wt%, more preferably at least 0.1 wt%, even more preferably at least 0.5 wt% and most preferably at least 1 wt%, based on the total weight of the ODF.

Typically, the total amount of the endothelin receptor antagonist, the water-soluble polymer and additional excipients including the plasticizer, surfactant and ODF excipients (when present) add up to 100 wt% in the ODF of the invention.

The invention further pertains to orally disintegrating tablets, also referred to as "ODT" or "orodispersible tablets". The orally disintegrating tablet of the invention comprises a disintegrant, an ETA, preferably ambrisentan, and optionally a binder.

The disintegrant, also referred to as "superdisintegrant" can be any disintegrant known in the art that can be suitably used in ODTs of the invention. Examples of such disintegrants include crosslinked polyvinyl pyrrolidone such as crospovidone; microcrystalline cellulose; crosslinked cellulose such as Crosscarmellose^®, Ac-Di-Sol^®, Primellose^® and Vivasol^®; crosslinked starch such as sodium starch glycolate; sodium carboxymethyl cellulose and hydroxypropyl ethyl cellulose; pregelatinized starch; soya polysaccharides; calcium silicate, and crosslinked alginic acid such as alginic acid NF. In one embodiment of the invention, the ODT comprises the disintegrant in an amount of at most 99.9 % by weight (wt%), based on the total weight of the ODT. Preferably, the disintegrant is present in an amount of at most 99.5 wt%, more preferably at most 99 wt%, and most preferably at most 98 wt%, and preferably at least 85 wt%, more preferably at least 90 wt%, even more preferably at least 92 wt%, even more preferably at least 93 wt% and most preferably at least 95 wt%, based on the total weight of the ODT.

The binder can be any binder known in the art that can be suitably used in ODTs of the invention. Examples of such binders include polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) and hydroxypropyl methyl cellulose (HPMC).

In one embodiment of the invention, the ODT comprises the binder in an amount of at most 15 % by weight (wt%), based on the total weight of the ODT. Preferably, the binder is present in an amount of at most 10 wt%, more preferably at most 8 wt%, even more preferably at most 7 wt% and most preferably at most 5 wt%, and preferably at least 0.01 wt%, more preferably at least 0.1 wt%, even more preferably at least 0.5 wt% and most preferably at least 1 wt%, based on the total weight of the ODT.

In one embodiment of the invention, the ODT comprises ambrisentan in an amount of at most 1 % by weight (wt%), based on the total weight of the ODT. Preferably, ambrisentan is present in an amount of at most 0.5 wt%, more preferably at most 0.2 wt%, even more preferably at most 0.1 wt% and most preferably at most 0.05 wt%, and preferably at least 0.0001 wt%, more preferably at least 0.0005 wt%, even more preferably at least 0.001 wt% and most preferably at least 0.0015 wt%, based on the total weight of the ODT.

The ODT of the invention may further comprise ODT excipients. The ODT excipients may be any excipient known in the art that can be suitably used in ODTs of the invention. Examples of such ODT excipients include lubricants such as stearic acid, magnesium stearate, zinc stearate, calcium stearate, talc, polyethylene glycol, liquid paraffin, magnesium lauryl sulfate and colloidal silicon dioxide; fillers such as mannitol, sorbitol, xylitol, calcium carbonate, magnesium carbonate, calcium phosphate, calcium sulfate, pregelatinized starch, magnesium trisilicate and aluminium hydroxide; surfactants such as sodium dodecyl sulfate, sodium lauryl sulfate, polyoxyethylene sorbitan fatty acids (sold under tradename Tween^®), sorbitan fatty acid esters (sold under tradename Span^®) and polyoxyethylene stearates; flavors such as mint, licorice and sucralose; sweetening agents such as fructose, mannitol, sorbitol, aspartame and saccharose; saliva stimulating agents such as citric acid, malic acid, tartaric acid, ascorbic acid and lactic acid; and coloring agents such as titanium dioxide, amaranth, sunset yellow and red iron oxide.

In one embodiment of the invention, the ODT comprises the ODT excipient in an amount of at most 15 % by weight (wt%), based on the total weight of the ODF. Preferably, the ODT excipient is present in an amount of at most 10 wt%, more preferably at most 8 wt%, even more preferably at most 7 wt% and most preferably at most 5 wt%, and preferably at least 0.01 wt%, more preferably at least 0.1 wt%, even more preferably at least 0.5 wt% and most preferably at least 1 wt%, based on the total weight of the ODT.

Typically, the total amount of the endothelin receptor antagonist, the disintegrant, the binder and the ODT excipients (when present) add up to 100 wt% in the ODT of the invention.

In one embodiment, the formulation of the ETA antagonist, preferably ambrisentan, according to the invention is a parenteral formulation. Other forms of parenteral administration also are contemplated, such as subcutaneous, transdermal, intraperitoneal and intramuscular. Of these forms, subcutaneous is preferred. Doses that are not administered orally have the additional advantage of being appropriate for subjects who are unable to swallow, such as subjects suffering from a neurological deficit or hepatic encephalopathy or those subjects under anesthesia or similar conditions. Parenteral administration has the advantage that the antagonist is more effective in a shorter period of time than alternative administration methods, and the desired blood concentration can be reached readily. Additionally, the dose can be adjusted in a simple manner, which may be necessary in view of the metabolic and functional characteristics of the subject.

The present invention further pertains to a liquid composition for parenteral administration comprising an endothelin receptor antagonist, a buffer and a solvent. Preferably, the invention pertains to a liquid composition for parenteral administration comprising ambrisentan, a buffer and a solvent. The liquid composition of the invention is preferably substantially free of particles.

More preferably, the liquid composition of the invention is free of particles. With "particles" is meant any kind of solids including particles of the endothelin receptor antagonist, dust particles or polymeric particles. The term "substantially free of particles" refers to solid particles being present in amounts and sizes as prescribed in the Pharmacopeia and acceptable according to regulatory standards.

In one embodiment of the invention, the liquid compositions comprise the endothelin receptor antagonist, preferably ambrisentan, in an amount of at most 15 % by weight (wt%), based on the total weight of the liquid composition. Preferably, the endothelin receptor antagonist, preferably ambrisentan, is present in an amount of at most 10 wt%, more preferably at most 5 wt%, even more preferably at most 2 wt% and most preferably at most 1 wt%, and preferably at least 0.00001 wt%, more preferably at least 0.0001 wt%, even more preferably at least 0.0005 wt% and most preferably at least 0.001 wt%, based on the total weight of the liquid composition.

In one embodiment of the invention, the liquid composition comprises the buffer in an amount of at most 15 % by weight (wt%), based on the total weight of the liquid composition. Preferably, the buffer is present in an amount of at most 10 wt%, more preferably at most 8 wt%, even more preferably at most 7 wt% and most preferably at most 5 wt%, and preferably at least 0.01 wt%, more preferably at least 0.1 wt%, even more preferably at least 0.5 wt% and most preferably at least 1 wt%, based on the total weight of the liquid composition.

Suitable solvents for use in the compositions of the invention include water, alcohols such as ethanol, glycerin, polyethylene glycol such as PEG300, PEG400 and PEG600; propylene glycol, N-methyl-2-pyrrolidone, and combinations of two or more of these solvents. Of these solvents water, ethanol, propylene glycol and polyethylene glycol or combinations comprising predominantly any one of these solvents are preferred. In another preferred embodiment, the composition of the invention does not contain water as solvent, and more preferably the composition is free from water. In one embodiment of the invention, the liquid composition comprises the solvent in an amount of at least 85 % by weight (wt%), based on the total weight of the liquid composition. Preferably, the solvent is present in an amount of at least 90 wt% and most preferably at least 92 wt%, and preferably at most 99.9 wt%, more preferably at most 98 wt%, and most preferably at most 95 wt%, based on the total weight of the liquid composition. Typically, the total amount of the endothelin receptor antagonist, the buffer, the solvent and additional excipients (when present) add up to 100 wt% in the liquid compositions of the invention.

When a buffer is present in the liquid composition, the buffer used in the composition of the invention may be any buffer known in the art which can be suitably used for parenteral administration. The buffer generally serves to maintain the composition at a constant pH, in particular upon storage and when the composition is moderately diluted. In one embodiment of the invention, the buffer is chosen such that the pH of the composition is generally between 6 and 12, preferably the pH is at least 6.5, more preferably at least 7, and preferably the pH is at most 10, and more preferably at most 9. Particularly preferred are compositions comprising ambrisentan having a pH of at least 9, as these compositions typically have a better stability and may have a higher concentration of ambrisentan.

In an embodiment of the invention, the pH of the resulting parenteral composition after adding the concentrated liquid composition of the invention is generally between 6 and 12, preferably the pH is at least 6.5, more preferably at least 7, and preferably the pH is at most 9, and more preferably at most 8.

Examples of suitable buffers include ammonium acetate, arginine, sodium benzoate, disodium citrate, trisodium citrate, diethanol amine, hydrobromic acid, monoethanol amine, phosphoric acid, monobasic sodium phosphate, dibasic sodium phosphate, tribasic sodium phosphate, monobasic potassium phosphate, dibasic potassium phosphate, tris(hydroxymethyl)methylamine (Tromethamine orTris), 4-2-hydroxyethyl-l- piperazineethanesulfonic acid (HEPES), and 2(R)-2-(methylamino)succinic acid, and combinations of two or more of said buffers. It is also contemplated to combine one or more of the mentioned buffers with one or more buffer agents having a pKa below 6 and above 10 as long as the overall pH of the composition of the invention is between 6 and 10.

The liquid composition may be comprised of other components commonly used in liquid compositions for parenteral administration. When the liquid formulation of the invention comprises components other than the endothelin receptor antagonist or ambrisentan, the buffer and the solvent, the total amount of the endothelin receptor antagonist or ambrisentan, the buffer, the solvent, and the other components, such as excipients, add up to 100 wt% of the total weight of the liquid composition.

The compositions of the invention may further comprise excipients. Suitable excipients are known in the art. Such excipients include, stabilizers and/or bulking agents such as mannitol, sucrose, trehalose, polyethylene glycol; tonicity agents like dextrose, sodium chloride, glycerol, glycerin and mannitol; viscosity enhancers or reducers such as sodium carboxymethyl cellulose, acacia, gelatin, methyl cellulose and polyvinyl pyrrolidone; surfactants like polyoxyethylene sorbitan monooleate (Tween 80), sorbitan monooleate, polyoxyethylene sorbitan monolaurate (Tween 20), polyoxyethylene polyoxypropylene copolymers (Pluronics), and lecithin; chelates like calcium disodium ethylenediaminetetra acetic acid (EDTA), disodium EDTA, sodium EDTA, calcium versetamide Na, calteridol and diethylenetriaminepenta acetic acid (DTPA); antioxidants such as acetyl cysteine, sulfurous acid salts (bisulfites and metasulfites), antimicrobial agents like phenol, meta-cresol, benzyl alcohol, methyl paraben, propyl paraben and butyl paraben; and other adjuvants. It is appreciated that some excipients may have multiple properties.

In one embodiment of the invention, the liquid composition comprises the excipient in an amount of at most 15 % by weight (wt%), based on the total weight of the liquid composition. Preferably, the buffer is present in an amount of at most 10 wt%, more preferably at most 8 wt%, even more preferably at most 7 wt% and most preferably at most 5 wt%, and preferably at least 0.01 wt%, more preferably at least 0.1 wt%, even more preferably at least 0.5 wt% and most preferably at least 1 wt%, based on the total weight of the liquid composition. In a preferred embodiment, the liquid composition of the invention is isotonic. In a preferred embodiment, the liquid composition of the invention is sterile.

The liquid compositions of the invention can be prepared using conventional techniques.

Liquid compositions for parenteral administration can be provided in any suitable container including but not limited to an ampoule, a vial, a pre-filled syringe, a cartridge for a subcutaneous pump, a cartridge for a subcutaneous pen, medication reservoir for a subcutaneous pump or an IV container such as an IV bag or bottle. The concentration of the ETA receptor antagonist may differ depending on the container used in order to achieve clinical benefit.

The liquid compositions may be administered directly to the subject. They also initially may be stored or formulated in concentrated forms that will be diluted in an appropriate parenteral solution, such as conventional physiological solutions for intravenous administration, pharmaceutically acceptable organic solvents such as propylene glycol and ethanol, or combinations thereof, before being administered. Appropriate buffers, excipients and preservatives are conventional. Examples of such parenteral solutions include saline solutions (sterile aqueous solutions of sodium chloride), Ringer's lactate solution, Hartmann's solution (comprising sodium lactate), dextrose-containing solutions (like D5W or D10W) and solutions combining any of the foregoing ingredients (like D5NS or D5LR), and pharmaceutically acceptable organic solvents such as propylene glycol and ethanol, or combinations thereof.

The liquid compositions may be added to the conventional parenteral solutions using conventional techniques. The dilution factor of the endothelin receptor antagonist may be at least 5, which means that, for example, 1 ml of the liquid composition of the invention is added to 200 ml of the conventional parenteral solutions. Preferably, the dilution factor is at least 10 and most preferably at least 15, and generally at most 500, preferably at most 100, and most preferably at most 50.

The invention further pertains to transdermal patches. The transdermal patch may be any known transdermal patch in the art comprising the ETA antagonist, preferably ambrisentan. The transdermal patch of the invention generally comprises the ETA antagonist, preferably ambrisentan, a polymer matrix and/or drug reservoir, optionally a permeation enhancer, optionally a pressure sensitive adhesive, a backing laminate, a release liner and optionally other transdermal patch excipients. Such transdermal patches may be a single-layer-drug-in-adhesive system, a reservoir system, a matrix system such as a drug-in-adhesive system or a matrix-dispersion system, and a micro-reservoir system such as described in Sharma (in Organic & Medicinal Chem IJ 7(2), OMCIJ. MS. ID.555707 (2018), pp.1-5).

The polymer matrix or drug reservoir can be any polymer known in the art that can be suitably used in transdermal patches of the invention. Examples of such polymer matrices include natural polymers such as cellulose derivatives, zein, gelatin, shellac, waxes, gums, natural rubber; synthetic elastomers such as polybutadiene, hydrin rubber, silicon rubber, polyisobutylene, acrylonitrile, neoprene and butyl rubber; and synthetic polymers such as polyvinyl alcohol, polyvinyl chloride, polyethylene, polypropylene, polyacrylate, polyamide, polyuria, polyvinyl pyrrolidone and polymethylmethacrylate.

The permeation enhancer can be any permeation enhancer known in the art that can be suitably used in transdermal patches of the invention. Examples of such permeation enhancers include dimethyl sulphoxide (DMSO), azone, pyrrolidones such as methyl pyrrolidone; fatty acids such as lauric acid, myristyc acid, oleic acid, linoleic acid and capric acid; essential oils such as terpenes and terpenoids; oxazolidinones such as 4- decyloxazolidin-2-one; and urea.

The pressure sensitive adhesive can be any pressure sensitive adhesive known in the art that can be suitably used in transdermal patches of the invention. Examples of such pressure sensitive adhesive include polyacrylates, polyisobutylene and silicon-based adhesives.

The backing laminate can be any backing laminate known in the art that can be suitably used in transdermal patches of the invention. Examples of such backing laminates include vinyl, polyethylene and polyester films. The release liner can be any release liner known in the art that can be suitably used in transdermal patches of the invention. Examples of such release liners include non-occlusive release liners made of paper fabric, for instance; and occlusive release liners made of, for example, polyethylene and polyvinylchloride.

The transdermal patch of the invention may further comprise TP excipients. The TP excipients may be any excipient known in the art that can be suitably used in transdermal patches of the invention. Examples of such TP excipients include solvents such methanol, chloroform, methanol, acetone, isopropanol and dichloromethane; and plasticizers such as dibutyl phthalate, triethyl citrate, polyethylene glycol and polypropylene glycol.

The size, thickness and amounts of the various features used in the transdermal patch of the invention are conventionally used values.

In general, it is contemplated that persons skilled in the art will adjust the amount of ETA (or ambrisentan) and formulation by conventional means as is appropriate for administration to a particular subject.

The above embodiments of the liquid composition of the invention also apply to zibotentan and atrasentan, and their individual embodiments are also included.

The above embodiments of the orodispersible tablet composition of the invention also apply to zibotentan and atrasentan, and their individual embodiments are also included.

The above embodiments of the orodispersible film composition of the invention also apply to zibotentan and atrasentan, and their individual embodiments are also included.

The above embodiments of the transdermal patch composition of the invention also apply to zibotentan and atrasentan, and their individual embodiments are also included.

EXAMPLES

Examples 1 and 2: Preparation of ambrisentan oral solutions

Two oral solutions comprising respectively 500 m (Example 1) and 1 mg (Example 2) ambrisentan per ml of solvent were prepared. First 5 mL Ethanol and 90 mL propylene glycol 1,2 were mixed together. The resulting solution was heated to 40 °C. Subsequently,

4S the necessary amount of ambrisentan was added and the solution was stirred until the ambrisentan completely dissolved. The resulting solution was cooled and sterilized by passing the solution through a suitable filter. The resulting liquid composition is in accordance with the invention and contains 500 pg/mL of ambrisentan (Example 1) and 1 mg/mL of ambrisentan (Example 2). Analyzing the resulting liquid composition showed that ambrisentan remained stable and no decomposition was observed.

Example 3: Preparation of Ambrisentan parenteral formulation:

A liquid composition comprising 5 mg ambrisentan per ml of solvent was prepared.

First 2750 g Ethanol and 2750 g propylene glycol 1,2 were mixed together. The resulting solution was heated to 40 °C. Subsequently, 30.27 g of ambrisentan were added to 5469.7 g of the solution. The solution was stirred until the ambrisentan completely dissolved. The resulting solution was cooled and sterilized by passing the solution through a suitable filter. The resulting liquid composition is in accordance with the invention and contains 5 mg/mL of ambrisentan. Analyzing the resulting liquid composition showed that ambrisentan remained stable and no decomposition was observed.

The solution obtained can be diluted in various ratios with an aqueous saline and other buffers having pH 6 and above. It is anticipated that prior to human administration, the physician will mix with sterile aqueous solution to obtain the desired ambrisentan concentration.

Stability tests

The liquid composition of Example 3 was tested for its stability. The tests were conducted by applying 5 ml of the solution in vials which are stored at different temperatures, i.e., 5°C and 25°C for up to 48 months in conditioned chambers. The solutions did not reveal any significant chemical and physical decomposition of ambrisentan at 5°C and significant degradation was observed at 25°C. Examples 4-9: Water-free ambrisentan parenteral formulations Various compositions in accordance with the invention and Example 3 above using a variety of solvents were prepared. To ambrisentan, the solvents or solvent mixtures were added and stirred. An overview of the ingredients of these compositions are presented in the Table 1 below.

Table 1 - Water-free ambrisentan formulations

In addition to the above examples further binary and tertiary solutions can be prepared for this purpose. The invention described in this specification generally relates to methods and formulations for the treatment and prevention of pulmonary complications of a coronavirus infection comprising the administration of ETA antagonists. While certain exemplary embodiments have been described above in detail and, it is to be understood that such embodiments and examples are merely illustrative of and not restrictive of the broad invention. In particular, it should be recognized that the teachings of the invention apply to variations of the preferred embodiments that are specifically discussed. Modifications, substitutions, changes and equivalents will now occur to those skilled in the art. Thus, it will be understood that the invention is not limited to the particular embodiments or arrangements disclosed, but is rather intended to cover any changes, adaptations or modifications which are within the scope and spirit of the invention as defined by the appended claims. Example 10: Effect of ambrisentan at plasma concentrations below 20 g/mL on pulmonary pressures.

In the context of a clinical study, a subject with a history of cirrhosis, the latter a condition associated with the presence of pulmonary hypertension, underwent right-heart catheterization to assess pulmonary pressures. The purpose of the study was to determine if low dose ambrisentan achieving concentrations of less than 20 ng/mL in plasma can reduce pulmonary pressures, among others.

Following a baseline assessment, the subject initiated a 14-day administration regimen of 2 pg of ambrisentan per day in a liquid solution of propylene glycol and ethanol. The solution was administered orally. Pulmonary pressures were assessed at baseline (pre-dose of ambrisentan) at 90 minutes post-dose, and on day 14, prior to and 90 minutes after the last dose of ambrisentan. Plasma concentrations of ambrisentan were measured at Day 14 prior to the last dose and at 240 minutes after the last dose. Plasma endothelin levels were measured throughout the study and until day 17 after the administration of the first dose of ambrisentan. The dose of 2 pg of ambrisentan to be tested in this study was derived and predicted with the aid of a pharmacokinetic model to achieve plasma concentrations of ambrisentan below 20 ng/mL in patients with impaired liver function. The dose of 2 pg of ambrisentan used in this study is 2500-fold lower that the lowest dose of ambrisentan approved for pulmonary arterial hypertension.

At baseline (Table 2), the subject presented with an elevated pulmonary arterial systolic pressure (PASP) of 37 mmHg and above the normal range of 18 to 25 mmHg. At 90 minutes after the first dose of ambrisentan, PASP had decreased to 27 mmHg. However, following a 14-day administration of ambrisentan, PASP had decreased to 22 mmHg, a 40% reduction from baseline. Still on Day 14, and at 90 minutes following the last dose, PASP was 25 mmHg and within normal range. At baseline, the mean Pulmonary Arterial Pressure (mPAP, calculated as 2/3rd of PADP + l/3rd of PASP/ 3) was 15 mmHg. At Day 14, the mPAP was 11 mmHg, a 27% reduction from baseline. On Day 14, the plasma concentrations of ambrisentan were measured at 0.314 ng/mL prior to the last dose and 0.755 ng/mL at 240 minutes after the last dose and remaining well below 20 ng/mL Plasma endothelin did not change significantly between baseline and day 17 of the study.

The experiment suggests that ambrisentan at plasma concentrations below 20 ng/mL reduces pulmonary pressures. The study also suggests ambrisentan at plasma concentrations below 20 ng/mL does not block the ETB receptor and does not prevent the clearance of endothelin by this receptor, as no significant elevation of plasma endothelin was observed.

Table 2 - Pulmonary Pressures following administration of a dose of ambrisentan to maintain plasma concentrations of ambrisentan below 20 ng/mL

Example 11: Effect of ambrisentan on respiratory function and progression to respiratory failure in patients with Severe COVID-19.

In the context of a double-blind, randomized, placebo-controlled clinical study (https://clinicaltrials.gov/ct2/show/NCT04771000), 150 adult subjects (from 50 to 85 years of age) with laboratory-confirmed SARS-CoV-2 infection and classified as having Severe COVID-19 were randomized to receive ambrisentan or placebo. In this study, respiratory function was evaluated at Baseline, Day 1, Day 2, Day 3 and Day 14 following the administration of ambrisentan or placebo for up to 28 days. In addition, the progression rate to respiratory failure (defined as those patients requiring mechanical ventilation, dying, requiring intubation or intensive care, among others) was also assessed. Secondary objectives of the study included the duration of oxygen therapy, the clinical status of the subject at Day 30 and the time to hospital discharge, among others.

This double-blinded study is ongoing, and results cannot be disclosed at this time but will be available in the future. The references referred to in the description are shown below and form part of the description.

[1] M. Ackermann et al., "Pulmonary vascular endothelialitis, thrombosis, and angiogenesis in Covid-19," N. Engl. J. Med., vol. 383, no. 2, pp. 120-128, 2020.

[2] Z. Varga et a!., "Endothelial cell infection and endotheliitis in COVID-19," Lancet, vol. 395, no. 10234, pp. 1417-1418, 2020.

[3] H. K. Siddiqi, P. Libby, and P. M. Ridker, "COVID-19 - A vascular disease," Trends Cardiovasc. Med., vol. 31, no. 1, pp. 1-5, Jan. 2021.

[4] W.-J. Guan et a!., "Clinical Characteristics of Coronavirus Disease 2019 in China.," N. Engl. J. Med., pp. 1-13, 2020.

[5] G. Grasselli et a!., "Baseline Characteristics and Outcomes of 1591 Patients Infected With SARS-CoV-2 Admitted to ICUs of the Lombardy Region, Italy.," Jama, pp. 1-8, 2020.

[6] F. Zhou et a!., "Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study," Lancet, vol. 395, no. 10229, pp. 1054-1062, 2020.

[7] L. Gattinoni, S. Coppola, M. Cressoni, M. Busana, and D. Chiumello, "Covid-19 Does Not Lead to a 'Typical' Acute Respiratory Distress Syndrome.," Am. J. Respir. Crit. Care Med., pp. 1-5, 2020.

[8] L. Gattinoni et a!., "COVID-19 pneumonia : different respiratory treatment for different phenotypes ?," Intensive Care Med., pp. 1-6, 2020.

[9] L. Gattinoni, D. Chiumello, and S. Rossi, "COVID-19 pneumonia: ARDS or not?," Crit. Care, vol. 24, no. 1, p. 154, 2020.

[10] M. G. Santamarina et al., "COVID-19 : a hypothesis regarding the ventilation- perfusion mismatch," pp. 4-7, 2020.

[11] Q. Deng et al., "Suspected myocardial injury in patients with COVID-19: Evidence from front-line clinical observation in Wuhan, China.," Int. J. Cardiol., vol. 311, no. January, pp. 116-121, 2020.

[12] M. Pagnesi et al., "Pulmonary hypertension and right ventricular involvement in hospitalised patients with COVID-19," Heart, vol. 106, no. 17, pp. 1324-1331, 2020.

[13] C. Tudoran et a!., "Evidence of Pulmonary Hypertension after SARS-CoV-2 Infection in Subjects without Previous Significant Cardiovascular Pathology.," !. Clin. Med., vol. 10, no. 2, p. 199, Jan. 2021.

[14] J. Norderfeldt et ai., "Acute pulmonary hypertension and short-term outcomes in severe Covid-19 patients needing intensive care," Acta Anaesthesiol. Scand., p. aas.13819, Mar. 2021.

[15] A. Esposito et ai, "Chest CT-derived pulmonary artery enlargement at the admission predicts overall survival in COVID-19 patients: insight from 1461 consecutive patients in Italy," Eur. Radiol., vol. 13, no. 11, pp. 2467-2468, Dec. 2020.

[16] S. E. Fox, A. Akmatbekov, J. L. Harbert, G. Li, J. Quincy Brown, and R. S. Vander Heide, "Pulmonary and cardiac pathology in African American patients with COVID-19: an autopsy series from New Orleans," Lancet Respir. Med., vol. 8, no. 7, pp. 681-686, Jul. 2020.

[17] J. Kim et ai, "Prognostic Utility of Right Ventricular Remodeling Over Conventional Risk Stratification in Patients With COVID-19," !. Am. Coll. Cardiol., vol. 76, no. 17, pp. 1965-1977, Oct. 2020.

[18] A. D'Andrea et ai., "Right Ventricular Function and Pulmonary Pressures as Independent Predictors of Survival in Patients With COVID-19 Pneumonia," JACC Cardiovasc. Imaging, vol. 13, no. 11, pp. 2467-2468, Nov. 2020.

[19] L. Chen et ai., "Novel Coronavirus-lnduced Right Ventricular Failure and Point of Care Echocardiography: A Case Report," Cardiol., vol. 145, no. 7, pp. 467-472, 2020.

[20] Y. Cao, M. Zhang, Y. Guo, and Y. Zhang, "The overlooked chamber in coronavirus disease 2019," ESC Hear. Fail., no. September, pp. 3483-3486, 2020.

[21] P. Huette et ai., "Acute Cor Pulmonale in COVID-19-Related ARDS," JACC Case Reports, vol. 2, no. 9, pp. 1311-1314, 2020.

[22] Y. Szekely et ai., "Spectrum of Cardiac Manifestations in COVID-19: A Systematic Echocardiographic Study," Circulation, vol. 142, no. 4, pp. 342-353, 2020.

[23] C. M. van Dongen et ai., "Unusually Rapid Development of Pulmonary Hypertension and Right Ventricular Failure after COVID-19 Pneumonia.," Eur. J. case reports Intern. Med., vol. 7, no. 7, p. 001784, 2020.

[24] H. Karmouty-Quintana, R. A. Thandavarayan, S. P. Keller, S. Sahay, L. M. Pandit, and B. Akkanti, "Emerging Mechanisms of Pulmonary Vasoconstriction in SARS-CoV-2- Induced Acute Respiratory Distress Syndrome (ARDS) and Potential Therapeutic Targets," Int. J. Mol. Sci., vol. 21, no. 21, p. 8081, Oct. 2020.

[25] S. Javor and A. Salsano, "Why not consider an endothelin receptor antagonist against SARS-CoV-2?," Med. Hypotheses, vol. 141, no. 5, p. 109792, Aug. 2020.

[26] J. Nuche et a!., "Effect of coronavirus disease 2019 in pulmonary circulation. The particular scenario of precapillary pulmonary hypertension," Diagnostics, vol. 10, no. 8, 2020.

[27] F. Potus et a!., "Novel insights on the pulmonary vascular consequences of COVID- 19," Am. J. Physiol. Lung Cell. Mol. Physiol., vol. 319, no. 2, pp. L277-L288, 2020.

[28] V. Franco et a!., "Pulmonary vasodilators: beyond the bounds of pulmonary arterial hypertension therapy in COVID-19," Pulm. Circ., vol. 10, no. 4, 2020.

[29] X. Wang et al., "Pulmonary vascular endothelial injury and acute pulmonary hypertension caused by COVID-19: The fundamental cause of refractory hypoxemia?," Cardiovasc. Diagn. Ther., vol. 10, no. 4, pp. 891-897, 2020.

[30] S. Farha and G. A. Heresi, "COVID-19 and Pulmonary Arterial Hypertension: Early Data and Many Questions," Ann. Am. Thorac. Soc., vol. 17, no. 12, pp. 1528-1530, Dec. 2020.

[31] S. Farha, "COVID-19 and pulmonary hypertension: Posted may 1, 2020," Cleve. Clin. J. Med., vol. 87, no. 5, pp. 1-3, 2020.

[32] C. Beige et al., "COVID-19 in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: a reference centre survey," ERJ Open Res., vol. 6, no. 4, pp. 00520-02020, 2020.

[33] J. F. Park, S. Banerjee, and S. Umar, "In the eye of the storm: the right ventricle in COVID-19," Pulm. Circ., vol. 10, no. 3, 2020.

[34] G. Isgro, H. O. Yusuff, and V. Zochios, "The Right Ventricle in COVID-19 Lung Injury: Proposed Mechanisms, Management and Research Gaps," !. Cardiothorac. Vase. Anesth., 2021.

[35] A. K. Mishra, A. Lai, K. K. Sahu, A. A. George, K. Martin, and J. Sargent, "An update on pulmonary hypertension in coronavirus disease-19 (Covid-19)," Acta Biomed., vol. 91, no. 4, pp. 1-6, 2020.

[36] M. Yanagisawa et al., "A novel potent vasoconstrictor peptide produced by vascular endothelial cells.," Nature, vol. 332, no. 6163. pp. 411-415, 1988.

[37] B. Battistini, N. Berthiaume, N. F. Kelland, D. J. Webb, and D. E. Kohan, "Profile of past and current clinical trials involving endothelin receptor antagonists: the novel sentan' class of drug.," Exp. Biol. Med. (Maywood)., vol. 231, no. 6, pp. 653-95, Jun. 2006.

[38] M. M. Hoeper, "Definition, classification, and epidemiology of pulmonary arterial hypertension," Semin. Respir. Crit. Care Med., vol. 30, no. 4, pp. 369-375, 2009.

[39] R. Samransamruajkit, K. Moonviriyakit, P. Vanapongtipagorn, N. Prapphal, J. Deerojanawong, and Y. Poovorawan, "Plasma endothelin-1 in infants and young children with acute bronchiolitis and viral pneumonia.," Asian Pacific J. allergy Immunol., vol. 20, no. 4, pp. 229-34, Dec. 2002.

[40] R. Samransamruajkit, S. Gollapudi, C. H. Kim, S. Gupta, and E. Nussbaum, "Modulation of endothelin-1 expression in pulmonary epithelial cell line (A549) after exposure to RSV.," Int. J. Mol. Med., vol. 6, no. 1, pp. 101-105, 2000.

[41] A. C. D'Aprile, L. B. Fernandes, P. J. Rigby, and R. G. Goldie, "Impact of parainfluenza-3 virus infection on endothelin receptor density and function in guinea pig airways," Clin. Sci., vol. 103, no. SUPPL. 48, pp. 345-348, 2002.

[42] M. J. Carr, R. G. Goldie, and P. J. Henry, "Influence of respiratory tract viral infection on endothelin-l-induced potentiation of cholinergic nerve-mediated contraction in mouse trachea," Br. J. Pharmacol., vol. 119, no. 5, pp. 891-898, 1996.

[43] P. J. Henry, M. J. Carr, R. G. Goldie, and A. Y. Jeng, "The role of endothelin in mediating virus-induced changes in endothelin(B) receptor density in mouse airways," Eur. Respir. J., vol. 14, no. 1, pp. 92-97, 1999.

[44] T. C. Carpenter, S. Schomberg, and K. R. Stenmark, "Endothelin-mediated increases in lung VEGF content promote vascular leak in young rats exposed to viral infection and hypoxia," Am. J. Physiol. - Lung Cell. Mol. Physiol., vol. 289, no. 6 33-6, pp. 1075-1082, 2005.

[45] T. C. Carpenter and K. R. Stenmark, "Endothelin receptor blockade decreases lung water in young rats exposed to viral infection and hypoxia," Am. J. Physiol. - Lung Cell. Mol. Physiol., vol. 279, no. 3 23-3, pp. 547-554, 2000.

[46] A. K. Behera, M. Kumar, H. Matsuse, R. F. Lockey, and S. S. Mohapatra, "Respiratory syncytial virus induces the expression of 5-lipoxygenase and endothelin-1 in bronchial epithelial cells," Biochem. Biophys. Res. Commun., vol. 251, no. 3, pp. 704-709, 1998.

[47] M. Browatzki, J. Schmidt, W. Kubler, and R. Kranzhofer, "Endothelin-1 induces interleukin-6 release via activation of the transcription factor NF-KB in human vascular smooth muscle cells," Basic Res. Cardiol., vol. 95, no. 2, pp. 98-105, 2000.

[48] K. Adachi, R. D. Soejoedono, E. Handharyani, M. Inai, and Y. Tsukamoto, "Therapeutic Trial of an Endothelin Receptor Agonist for the Highly Pathogenic Avian Influenza A/H5N1 Virus Infection in Chicks," Health (Irvine. Calif)., vol. 06, no. 19, pp. 2553- 2561, 2014.

[49] M. Imai et a!., "Rescue with an anti-inflammatory peptide of chickens infected H5N1 avian flu," Nat. Preced., pp. 4-6, 2009.

[50] V. M. Ranieri et al., "Acute respiratory distress syndrome: The Berlin definition,"

JAMA - J. Am. Med. Assoc., vol. 307, no. 23, pp. 2526-2533, 2012.

[51] G. Simonneau et al., "Updated Clinical Classification of Pulmonary Hypertension," J. Am. Coll. Cardiol., vol. 62, no. 25, pp. D34-D41, Dec. 2013.

[52] M. J. Carr, L. J. Spalding, R. G. Goldie, and P. J. Henry, "Distribution of immunoreactive endothelin in the lungs of mice during respiratory viral infection," Eur. Respir. J., vol. 11, no. 1, pp. 79-85, 1998.

[53] S. Oparil, S. J. Chen, Q. C. Meng, T. S. Elton, M. Yano, and Y. F. Chen, "Endothelin-A receptor antagonist prevents acute hypoxia-induced pulmonary hypertension in the rat.," Am. J. Physiol., vol. 268, no. 1 Pt 1, pp. L95-100, Jan. 1995.

[54] P. A. Modesti et al., "Role of endothelin-1 in exposure to high altitude: Acute mountain sickness and endothelin-1 (ACME-1) study," Circulation, vol. 114, no. 13, pp. 1410-1416, 2006.

[55] P. J. Henry, "Respiratory viral infections and the endothelin system," Pulm.

Pharmacol. Ther., vol. 11, no. 2-3, pp. 133-140, 1998.

[56] M. M. Berger et al., "The effect of endothelin-1 on alveolar fluid clearance and pulmonary edema formation in the rat," Anesth. Analg., vol. 108, no. 1, pp. 225-231, 2009.

[57] J. Kamiyama et al., "Assessment of circulatory and pulmonary endothelin-1 levels in a lavage-induced surfactant-depleted lung injury rabbit model with repeated open endotracheal suctioning and hyperinflation," LifeSci., vol. 118, no. 2, pp. 370-378, 2014. [58] Y. Nakano et ol., "Endothelin-1 level in epithelial lining fluid of patients with acute respiratory distress syndrome," Respirology, vol. 12, no. 5, pp. 740-743, 2007.

[59] W. Druml et a!., "Endothelin-1 in adult respiratory distress syndrome," Am. Rev. Respir. Dis., vol. 148, no. 5, pp. 1169-1173, 1993.

Claims

1. Ambrisentan for use in the treatment of pulmonary complications of a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

2. Ambrisentan for use in the prevention of pulmonary complications of a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

3. Ambrisentan for use in the treatment of hypoxemia associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

4. Ambrisentan for use in the treatment of pulmonary edema associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

5. Ambrisentan for use in the treatment of pneumonia associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

6. Ambrisentan for use in the treatment of acute respiratory distress syndrome associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

7. Ambrisentan for use in the prevention of acute respiratory distress syndrome associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

8. Ambrisentan for use in the treatment of pulmonary hypertension associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

9. Ambrisentan for use in the prevention of pulmonary hypertension associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

10. Ambrisentan for use in the treatment of post-infectious persistent sequelae associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

11. Ambrisentan for use in the prevention of post-infectious persistent sequelae associated with a coronavirus infection, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

12. Ambrisentan for use in the treatment of pulmonary hypertension, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

13. Ambrisentan for use in the treatment of pulmonary arterial hypertension, wherein ambrisentan is administered to a treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

14. A method for treating a subject suffering from pulmonary complications of a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

15. A method for prophylactically treating a subject at risk of developing pulmonary complications of a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

16. A method for treating a subject suffering from hypoxemia associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

17. A method for treating a subject suffering from pulmonary edema associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

18. A method for treating a subject suffering from pneumonia associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

19. A method for treating a subject suffering from acute respiratory distress syndrome associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

20. A method for prophylactically treating a subject at risk of developing acute respiratory distress syndrome associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

21. A method for treating a subject suffering from pulmonary hypertension associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

22. A method for prophylactically treating a subject at risk of developing pulmonary hypertension associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

23. A method for treating a subject suffering from post-infectious persistent sequelae associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

24. A method for prophylactically treating a subject at risk of developing post-infectious persistent sequelae associated with a coronavirus infection comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

25. A method for treating a subject suffering from pulmonary hypertension comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.

26. A method for treating a subject suffering from pulmonary arterial hypertension comprising administering ambrisentan wherein an effective amount of ambrisentan is administered to the subject, wherein ambrisentan is administered to the treated subject such that the plasma levels of ambrisentan are maintained below about 20 ng/ml.