Methods for treating pulmonary hypertension

Abstract

The present invention relates to methods for treating or preventing pulmonary hypertension, reducing mortality in a subject experiencing pulmonary hypertension, or inhibiting ADP-mediated vasoconstriction of pulmonary arteries in a subject, comprising administering to the subject an effective amount of a pharmaceutical composition comprising a reversible P2Y.sub.12 receptor antagonist. Also provided are related medicaments, pharmaceutical compositions, and methods for preparing the medicaments.

Claims

1. A method of reducing pulmonary hypertension in a subject in need thereof, consisting of administering to the subject a pharmaceutical composition wherein the only active ingredient is an effective amount of cangrelor.

2. The method of claim 1, wherein the administration of cangrelor comprises a dose of about 0.1-100 mg/ml.

3. The method of claim 1, wherein the administration of cangrelor comprises intravenous administration.

4. The method of claim 3, wherein the administration of cangrelor comprises a bolus, a continuous infusion, or a combination thereof.

5. The method of claim 4, wherein the administration of cangrelor comprises a bolus followed by a continuous infusion.

6. The method of claim 4, wherein the administration of cangrelor comprises a bolus of about 1-100 μg/kg.

7. The method of claim 4, wherein the administration of cangrelor comprises continuous infusion of about 0.1 to 25 μg/kg/min.

8. The method of claim 4, wherein the administration of cangrelor comprises continuous infusion for a period of at least about 4 hours.

9. The method of claim 1, wherein the pharmaceutical composition comprises one or more pharmaceutically acceptable carriers, diluents, or a combination of different agents thereof.

10. A method of reducing pulmonary hypertension in a subject in need thereof, consisting of administering to the subject a pharmaceutical composition comprising only two active ingredients, wherein the first active ingredient is an effective amount of cangrelor, and the second active ingredient is selected from the group consisting of pulmonary vasodilator, digoxin, diuretic, anticoagulant, beta blocker, and angiotensin-converting enzyme (ACE) inhibitor.

11. The method of claim 10, wherein the pulmonary vasodilator is selected from the group consisting of prostaglandins, endothelin receptor antagonists, phosphodiesterase type 5 inhibitors and activators of soluble guanylated cyclase (sGC).

12. The method of claim 1, wherein the subject has suffered a stroke or a myocardial infarction.

13. The method of claim 1, wherein the subject has diabetes mellitus, hyperlipidemia, congestive heart failure, peripheral arterial disease (PAD), thrombosis in an artery or vein, or a family history of coronary artery disease (CAD).

14. The method of claim 1, wherein the subject has undergone percutaneous transluminal coronary angioplasty (PTCA), coronary intervention (PCI), or artery bypass graft (CABG).

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The present invention is based on the discovery that cangrelor, a reversible and rapid acting inhibitor of the P2Y.sub.12 receptor, is effective in attenuating ADP- and hypoxia-induced pulmonary vasoconstriction. In particular, cangrelor is effective in attenuating acute hypoxic pulmonary vasoconstriction (HPV) with fast onset of action.

(2) Cangrelor is a nonthienopyridine adenosine triphosphate analogue, which reversibly binds to and inhibits the P2Y.sub.12 ADP receptor. Cangrelor is direct-acting, reversible, and selective. Having a short half-life, cangrelor exhibits rapid onset and offset of effect. The chemical structure of cangrelor is shown in Formula I.

(3) ##STR00001##

(4) The term “cangrelor” as used herein encompasses the compound of Formula I, as well as tautomeric, enantiomeric and diastereomeric forms thereof, and racemic mixtures thereof, other chemically active forms thereof, and pharmaceutically acceptable salts of these compounds, including a tetrasodium salt. These alternative forms and salts, processes for their production, and pharmaceutical compositions comprising them, are well known in the art and set forth in U.S. Pat. No. 5,721,219. Additional disclosure relevant to the production and use of cangrelor may be found in U.S. Pat. Nos. 5,955,447, 6,130,208 and 6,114,313, as well as in U.S. Appln. Publication No. 2006/0270607.

(5) The present invention provides various methods, including a method for treating or preventing pulmonary hypertension in a subject in need thereof, a method for reducing mortality in a subject having pulmonary hypertension, and a method for inhibiting ADP-mediated vasoconstriction of pulmonary arteries in a subject. These methods comprise administering to the subject an effective amount of a pharmaceutical composition comprising a reversible P2Y.sub.12 receptor antagonist. Examples of reversible P2Y.sub.12 receptor antagonists include cangrelor, ticagrelor, AR-C67085, and elinogrel (PRT-060128). Preferably, the reversible P2Y.sub.12 receptor antagonist is cangrelor. Other reversible P2Y.sub.12 receptor antagonists may include compounds corresponding to formula I as set forth in U.S. Pat. No. 5,721,219, formula I as set forth in U.S. Pat. No. 5,955,447, formula I as set forth in U.S. Pat. No. 6,130,208, formula I as set forth in U.S. Pat. No. 6,114,313, or formula I as set forth in U.S. Appln. Publication No. 2006/0270607, and pharmaceutical acceptable salts thereof.

(6) The reversible P2Y.sub.12 receptor is preferably a rapid acting antagonist. The term “rapid acting” refers to fast onset and fast offset. A rapid acting drug reaches steady plasma drug concentration quickly (e.g., within less than about one hour, 45 minutes, 30 minutes, 15 minutes, 10 minutes, or 5 minutes after starting drug administration), and gets cleared quickly (e.g., within about five hours, three hours, one hour, 30 minutes, 15 minutes, 10 minutes, or 5 minutes after ending drug administration). Preferably, the rapid acting reversible P2Y.sub.12 receptor is cangrelor.

(7) The pulmonary hypertension (PH) may fall into any one of the different groups or subgroups of the PH clinical classification. For example, the PH may fall into one of the five main groups: pulmonary arterial hypertension (PAH), PH associated with left heart disease (PHLHD), PH associated with lung disease or hypoxia, chronic thromboembolic pulmonary hypertension (CTPH), and PH with unclear or multifactorial mechanisms. Criteria for diagnosis of PH are well known in the art.

(8) The PAH is clinically defined as a group of diseases characterized by a gradual increase in pulmonary vascular resistance leading to right ventricular failure and early death. Subias et al., Rev. Esp. Cardiol. 63(5):583-96 (2010). A PAH diagnosis requires invasive hemodynamic criteria, including a mean pulmonary artery pressure greater than 25 mm Hg at rest and a normal pulmonary capillary wedge or left ventricular end-diastolic pressure less than 15 mm Hg. Humbert, M. Am. J. Respir. Crit. Care Med 179:650-6 (2009); Hill et al., Respiratory Care 54(7):958-68 (2009).

(9) The PAH may be idiopathic pulmonary arterial hypertension (IPAH), heritable PAH, induced by a drug or toxin, associated with certain diseases, or persistent in a newborn. Examples of the PAH inducing drugs or toxins include aminorex, fenfluramine, dexfenfluramine, toxic rapeseed oil, cocaine, phenylpropanolamine, St. John's Wort, chemotherapeutic agents, SSRI, amphetamines, L-tryptophan and methamphetamines. The PAH associated diseases include connective tissue diseases, HIV infection, portal hypertension, congenital heart diseases (CHD), schistosomiasis, and chronic hemolytic anemia.

(10) The PH may also be pulmonary veno-occlusive disease (PVOD) or pulmonary capillary hemangiomatosis (PCH).

(11) In the PH associated with left heart disease (PHLHD), the left heart disease may be systolic dysfunction, diastolic dysfunction, or valvular disease.

(12) The PH may be caused by a lung disease and/or hypoxia. Hypoxia is a pathological condition in which oxygen does not reach body tissues due to inadequate oxygen supply, and may be caused by a lung disease, impaired control of breathing, or residence at high altitude. A lung disease may be selected from the group consisting of chronic obstructive pulmonary diseases, interstitial lung diseases, pulmonary diseases with a mixed restrictive and obstructive pattern, sleep-disordered breathing, alveolar hypoventilation disorders, chronic exposure to high altitude and developmental abnormalities. The chronic obstructive pulmonary disease may be a parenchymal lung disease. The pulmonary disease with a mixed restrictive and obstructive pattern may be chronic bronchiectasis, cystic fibrosis, or a syndrome characterized by a combination of pulmonary fibrosis and emphysema.

(13) Chronic thromboembolic pulmonary hypertension (CTEPH) is a frequent cause of PH, especially among patients after an acute pulmonary embolism. Currently, the only curative treatment of CTEPH is pulmonary thromboendarterectomy.

(14) The PH may also be associated with other various disorders, for example, hemotologic disorders (e.g., myeloproliferative disorders and splenectomy), systemic disorders (e.g., sarcoidosis, pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, neurofibromatosis, and vasculitis), metabolic disorders (e.g., glycogen storage disease, Gaucher disease, and thyroid disorder), tumoral obstruction, fibrosing mediastinitis, and chronic renal failure on dialysis.

(15) In some embodiments, the PH is postoperative PH. Postoperative PH could fall into any of the groups or subgroups of PH as set forth in the updated PH clinical classification. Preferably, the postoperative PH is PAH (e.g., congenital heart disease or portopulmonary hypertension preliver transplant) or PHLHD (e.g., chronic heart failure pre-transplant or left-ventricular diastolic dysfunction). The postoperative PH may be caused by organ transplantation, cardiac surgery, lung resection or thromboendarterectomy. The organ transplantation may be heart, lung, liver or kidney transplantation. The cardiac surgery may be valve repair or replacement, congenital heart repair, or left-ventricular-assist device implantation. The lung resection may be pneumonectomy or lobectomy. The postoperative HP may also be caused by factors indirectly associated with a surgery or procedure. Such factors include preoperative pulmonary hypertension, fluid overload, left-ventricular failure, acute lung injury or acute respiratory distress syndrome, pulmonary emboli, and acidosis and hypoxia.

(16) The subject may be a mammal, for example, a mouse, rat, dog, pig, or human, preferably a human. The subject may be male or female. The subject may also be a newborn. Preferably, the subject is at risk or has suffered from PH or ADP-mediated vasoconstriction of pulmonary arteries. More preferably, the subject exhibits one or more PH symptoms.

(17) In a method in accordance with the present invention, a pulmonary hypertension symptom in the subject is preferably ameliorated or improved. Examples of the PH symptoms include shortness of breath, fatigue, dizziness, fainting, peripheral edema (swelling in foot, legs or ankles, bluish lips and skin, chest pain, angina pectoris, light-headedness during exercise, non-productive cough, racing pulse and palpitations.

(18) The subject may have received a PAH inducing drug or toxin. PAH inducing drugs or toxins include aminorex, fenfluramine, dexfenfluramine, toxic rapeseed oil, cocaine, phenylpropanolamine, St. John's Wort, chemotherapeutic agents, SSRI, amphetamines, L-tryptophan and methamphetamines.

(19) The subject may have suffered from a PAH associated disease selected from the group consisting of connective tissue diseases, HIV infection, portal hypertension, congenital heart diseases (CHD), schistosomiasis and chronic hemolytic anemia.

(20) The subject may have suffered from a pulmonary veno-occlusive disease (PVOD) or pulmonary capillary hemangiomatosis (PCH).

(21) The subject may have suffered from a left heart disease. The left heart disease may be systolic dysfunction, diastolic dysfunction or valvular disease.

(22) The subject may have suffered from a lung disease, hypoxia, impaired control of breathing or residence at high altitude. Examples of lung diseases include chronic obstructive pulmonary diseases, interstitial lung diseases, pulmonary diseases with a mixed restrictive and obstructive pattern, sleep-disordered breathing, alveolar hypoventilation disorders, chronic exposure to high altitude and developmental abnormalities. The chronic obstructive pulmonary disease may be a parenchymal lung disease. The pulmonary disease with a mixed restrictive and obstructive pattern may be chronic bronchiectasis, cystic fibrosis, or a syndrome characterized by a combination of pulmonary fibrosis and emphysema.

(23) The subject may have suffered from one or more other PH associated disorders, including hemotologic disorders, systemic disorders, metabolic disorders, tumoral obstruction, fibrosing mediastinitis, and chronic renal failure on dialysis. The hemotologic disorder may be a myeloproliferative disorder or splenectomy. The systemic disorder may be sarcoidosis, pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, neurofibromatosis or vasculitis. The metabolic disorder may be a glycogen storage disease, Gaucher disease or thyroid disorder.

(24) The subject may have suffered a stroke, or the subject may not have suffered a stroke. The subject may have diabetes mellitus, or the subject may not have diabetes mellitus. The subject may have hypertension, or the subject may not have hypertension. The subject may have hyperlipidemia, or the subject may not have hyperlipidemia. The subject may have suffered a myocardial infarction, or the subject may not have suffered a myocardial infarction. The subject may have a family history of coronary artery disease (CAD), or the subject may not have a family history of CAD. The subject may have undergone percutaneous transluminal coronary angioplasty (PTCA), or the subject may not have undergone PTCA. The subject may have undergone percutaneous coronary intervention (PCI), or the subject may not have undergone PCI. The subject may have undergone coronary artery bypass graft (CABG), or the subject may not have undergone CABG. The subject may have congestive heart failure, or the subject may not have congestive heart failure. The subject may have peripheral arterial disease (PAD), or the subject may not have PAD. The subject may have thrombosis in an artery or vein, or the subject may not have thrombosis in an artery or vein.

(25) The term “an effective amount” refers to an amount of a pharmaceutical composition comprising a reversible P2Y.sub.12 receptor antagonist (e.g., cangrelor) required to achieve a stated goal (e.g., treating or preventing PH, reducing mortality, and/or inhibiting ADP-mediated vasoconstriction of pulmonary arteries). The effective amounts of the pharmaceutical compositions comprising a reversible P2Y.sub.12 receptor antagonist (e.g., cangrelor) may vary depending upon the stated goals, the physical characteristics of the subject, the nature and severity of the PH, existence of related or unrelated medical conditions, the nature of the reversible P2Y.sub.12 receptor antagonist, the composition comprising the reversible P2Y.sub.12 receptor antagonist (e.g., cangrelor), the means of administering the drug to the subject, and the administration route. A specific dose for a given subject may generally be set by the judgment of a physician. The pharmaceutical composition may be administered to the subject in one or multiple doses.

(26) The pharmaceutical composition may comprise about 0.1-100, 0.1-50, 0.1-25, 0.1-20, 0.1-10, 0.1-5, 0.1-2.5, 0.1-2, 0.1-1, 0.1-0.5, or 0.1-0.2 mg/ml (e.g., about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 mg/ml). The pharmaceutical composition may further comprise a pharmaceutically acceptable carrier or diluent. Suitable carriers, diluents and excipients are well known in the art.

(27) The pharmaceutical composition may be administered to the subject for a period of hours, days, weeks or months. It may also be administered once, twice, thrice or more times a day, once every two days, once every three days, once every four days, once every five days, once every six days, once a week, once every 10 days, once every two weeks, once every three weeks, once a month, or even less frequently.

(28) The pharmaceutical compositions of the present invention may be formulated, for example, for oral, sublingual, intranasal, intraocular, rectal, transdermal, mucosal, topical or parenteral administration. Parenteral administration may be intradermal, subcutaneous (s.c., s.q., sub-Q, Hypo), intramuscular (i.m.), intravenous (i.v.), intraperitoneal (i.p.), intra-arterial, intramedulary, intracardiac, intra-articular (joint), intrasynovial (joint fluid area), intracranial, intraspinal, and intrathecal (spinal fluids). Any device suitable for parenteral injection or infusion of drug formulations may be used for such administration. According to the present invention, the pharmaceutical compositions are preferably administered to the subject in an oral dosage form, an intravenous dosage form, or both. The intravenous dosage form may be a bolus intravenous dosage form or a continuous intravenous infusion dosage form.

(29) When administered as an intravenous (IV) formulation, the pharmaceutical composition may be administered as a bolus or as a continuous infusion. When administered in a bolus dosage form, the pharmaceutical compositions may be administered to the subject at about 1-1000, 1-500, 1-200, 1-100, 1-75, 1-50, 1-40, 1-30, 1-20, or 1-10 μg cangrelor per kg body weight (e.g., about 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 μg/kg), preferably about 20-40 μg/kg, more preferably about 30 μg/kg. When administered as a continuous intravenous infusion dosage form, the pharmaceutical composition may be administered to the subject at about 0.1-100, 0.1-50, 0.1-25, 0.1-10, 0.1-7.5, 0.1-5, 0.1-2.5, 0.1-2, 0.1-1, or 0.1-0.5 μg cangrelor per kg body weight per minute (e.g., about 0.1, 0.5, 1, 2, 5, 7.5, 10, 15, 20, 25, or 30 μg/kg/min), preferably about 1-10 μg/kg/min, more preferably about 4 ug/kg/min. The pharmaceutical composition may be administered continuously for a period of at least about 0.1, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, or 4 hours.

(30) When administered orally, the pharmaceutical composition may be administered to the subject in an oral dosage at about 0.1-1000, 0.1-500, 0.1-250, 0.1-100, 0.1-50, 1-50, 1-40, 1-30, 1-20, 1-10, or 1-5 mg cangrelor per kg body weight per day (e.g., about 1, 2, 3, 4, 5, 10, 15, 20, 25, 30, 40, 50, 100 or 500 mg/kg/day), preferably about 5-30 mg/kg/day, more preferably about 5, 10, 15, 20, 25, or 30 mg/kg/day. Oral administration may be as a single dose (bolus) or divided into multiple doses. When multiple doses are administered orally, administration may be once, twice, thrice or more times per day.

(31) In the method for treating or preventing pulmonary hypertension (PH) or reducing mortality in a subject having pulmonary hypertension (PH), administering an effective amount of the pharmaceutical composition comprising cangrelor may follow PH diagnosis or onset of one or more of the PH symptoms. In the method for inhibiting ADP-mediated vasoconstriction of pulmonary arteries in a subject, the administration may start after ADP-mediated vasoconstriction of pulmonary arteries is observed or suspected in the subject. Preferably, the pharmaceutical composition is administered to the subject within about 5, 10, 30, 60, 90 or 120 minutes of the PH diagnosis or the onset of one or more PH symptoms. The course of treatment may last for a period of hours, days, weeks or months. In preferred embodiments, the mortality is reduced by at least about 0.05%, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2%, 1.5%, 2%, or 5%.

(32) Where the subject undergoes an operation, the pharmaceutical composition may be administered to the subject prior to the operation (e.g., within 0.5, 1, 1.5, 2, 2.5, 3, 3.5, or 4 hours before starting the operation), during the operation, or after the operation (e.g., within 0.5, 1, 1.5, 2, 2.5, 3, 3.5, or 4 hours, 1 week, or 1 month after ending the operation). An operation may be a surgery (e.g., heart, lung, liver and kidney transplantation) or a procedure (e.g., valve repair/replacement, congenital heart repair, and left-ventricular-assist device implantation). A skilled artisan will understand that different dosages may be administered at different time points. Thus, the dosages may differ in the periods before, during, and after the operation.

(33) The methods according to the present invention may further comprise administering an active agent in an effective amount for treating PH or optimizing left ventricular function in the subject. Suitable active agents may be administered to the subject in the same composition comprising cangrelor or in a separation composition simultaneously or sequentially.

(34) Suitable active agents for treating PH include pulmonary vasodilators, digoxin, diuretics, and anticoagulants. Examples of the pulmonary vasodilator include prostaglandins, endothelin receptor antagonists, phosphodiesterase type 5 inhibitors, and soluble guanylated cyclase (sGC) activators. The prostaglandin may be intravenous epoprostenol, subcutaneous or intravenous treprostinil, or inhaled iloprost. The phosphodiesterase-5 inhibitor may be sildenafil or tadalafil. The endothelin receptor antagonist may be oral bosentan or oral ambrisentan.

(35) Suitable active agents for optimizing left ventricular function include diuretics, beta blockers, and ACE inhibitors.

(36) The methods according to the present invention may also include a procedure for treating PH (e.g., atrial septostomy, lung transplantation, and pulmonary throboendarterectomy (PTE)), or for optimizing left ventricular function (e.g., repair or replacement of a mitral valve or aortic valve).

(37) The methods according to the present invention may further comprise providing an oxygen therapy to the subject.

(38) Each of the methods according to the present invention may include an additional step of measuring the effect or effectiveness of the pharmaceutical composition during or after administration. For example, the additional step of measuring an effect of the pharmaceutical composition may be performed about 1, 2, 5, 10, 15, 30, or 45 min, or 1, 5, 10, 15, 20 or 24 hours, or more, after the completion of the method. The measuring step may include determining one or more haemodynamic measurements, including mean pulmonary artery pressure (MPAP), pulmonary vascular resistance (PVR), pulmonary capillary wedge pressure (PCWP), cardiac output (CO), systemic vascular resistance (SVR), mean right atrial pressure (MRAP), mean aortic blood pressure (MAP), heart rate (HR), stroke volume (SV) and blood-O2-consumption. Methods for determining these measurements are well known in the art.

(39) In some embodiments, medicaments comprising an effective amount of a reversible P2Y.sub.12 receptor antagonist is provided. They are useful for treating or preventing pulmonary hypertension, reducing mortality in a subject experiencing pulmonary hypertension, or inhibiting ADP-mediated vasoconstriction of pulmonary arteries. The reversible P2Y.sub.12 receptor antagonist is preferably a rapid acting antagonist, more preferably cangrelor.

(40) The medicaments may comprise cangrelor in an amount of about 0.1-100, 0.1-50, 0.1-25, 0.1-20, 0.1-10, 0.1-5, 0.1-2.5, 0.1-2, 0.1-1, 0.1-0.5, or 0.1-0.2 mg/ml, preferably about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 mg/ml. The medicaments may further comprise a pharmaceutically acceptable carrier or diluent, and/or an active agent suitable for treating PH or for optimizing left ventricular function.

(41) In some other embodiments, methods for preparing the medicaments according to the present invention are provided. The preparation methods comprise admixing a reversible P2Y.sub.12 receptor antagonist, preferably a rapid acting antagonist, more preferably cangrelor, with a pharmaceutically acceptable carrier or diluent. The methods may further comprise admixing an active agent suitable for treating PH or for optimizing left ventricular function. The method may further comprise admixing an active agent selected from the group consisting of pulmonary vasodilators, digoxin, diuretics, anticoagulants, diuretics, beta blockers, and ACE inhibitors. The pulmonary vasodilator may be selected from the group consisting of prostaglandins, endothelin receptor antagonists, phosphodiesterase type 5 inhibitors and activators of soluble guanylated cyclase (sGC).

(42) The term “about” as used herein when referring to a measurable value such as an amount, a percentage, and the like, is meant to encompass variations of ±20% or ±10%, more preferably ±5%, even more preferably ±1%, and still more preferably ±0.1% from the specified value, as such variations are appropriate.

Example 1. P2Y.SUB.12 .Receptor Antagonism with Cangrelor Attenuates ADP- and Hypoxia-Induced Pulmonary Vasoconstriction

(43) Hypoxic pulmonary vasoconstriction (HPV) may lead to pulmonary hypertension, right heart failure and death. As nucleotides may be released in hypoxia to influence vascular tone and ADP increases pulmonary artery pressure, the ADP P2Y.sub.12 receptor antagonist cangrelor was studied for its effects on pulmonary vasoconstriction induced by ADP and hypoxia.

(44) Haemodynamic measurements were performed in six anaesthetized, mechanically ventilated pigs (30.2±0.7 kg) in normoxia (FiO.sub.2˜0.21) and hypoxia (FiO.sub.2˜0.10) prior to and during right atrial cangrelor infusion at a loading dose of 30 μg/kg/min for 10 min, and then a continuous infusion at 4 μg/kg/min for 80 min. Another six pigs (29.3±0.5 kg) were investigated in normoxia before and during right atrial infusion of ADP at 70 μg/kg/min for ˜7 min; as well as before and during simultaneous ADP and cangrelor infusion for ˜7 min at doses of 70 μg/kg/min and 4 μg/kg/min, respectively, after a cangrelor loading dose of 30 μg/kg/min for 10 min. All data are mean±SEM.

(45) Protocol 1—Response to Hypoxia.

(46) Compared to normoxia (FiO.sub.2˜0.21), hypoxia (FiO.sub.2˜0.10); increased mean pulmonary artery pressure (MPAP) by 10.9±1.2 mmHg (p<0.05), pulmonary vascular resistance (PVR) by 1.6±0.3 WU (p<0.001), pulmonary capillary wedge pressure (PCWP) by 1.3±0.6 mmHg (p<0.038) and cardiac output (CO) by 0.9±0.3 l.Math.min.sup.−1 (p<0.009); and decreased systemic vascular resistance (SVR) by 4.9±1.7 WU (p<0.015); whereas mean right atrial pressure (MRAP), mean aortic blood pressure (MAP), heart rate (HR), stroke volume (SV) and blood-O.sub.2-consumption were unaltered (p=ns).

(47) Protocol 2—Response to Cangrelor During Hypoxia.

(48) Compared to hypoxia baseline, MPAP decreased transiently by 3.3±0.4 (p<0.036) and 3.6±0.6 mmHg (p<0.018), respectively, 10 and 30 min after initiation of cangrelor infusion; but returned to levels not different (p=ns) from baseline 60 and 90 min after initiation of cangrelor infusion. PVR, MRAP, PCWP, MAP, SVR, CO, HR, SV and blood-O.sub.2-consumption were unaltered by cangrelor infusion during hypoxia (p=ns).

(49) Protocol 3—Response to ADP During Normoxia.

(50) ADP infusion during normoxia increased MPAP, temporarily to peak at 35.2±1.9 mmHg, 19.3±1.6 mmHg higher (p<0.001) than baseline, to then stabilize at a level 10.4±1.6 mmHg higher (p<0.001) than baseline, and 8.9±1.4 mmHg lower (p<0.001) than the peak, after ˜4-7 min. Also, after ˜4-7 min from initiation of ADP infusion, PVR had increased (p<0.002) by 2.8±0.4 WU and PCWP by 2.5±0.7 mmHg (p<0.019), compared to baseline. ADP infusion during normoxia decreased MAP, first to reach a nadir at 39.8±6.1 mmHg, 48.5±6.0 mmHg lower (p<0.001) than baseline, however, then stabilizing, after ˜4-7 min, at a level not different (p=ns) from, although slightly lower than, baseline, and 41.7±8.9 mmHg higher (p<0.001) than the nadir. MRAP, SVR, CO, HR, SV and blood-O.sub.2-consumption were unchanged (p=ns) by ADP infusion during normoxia. However, MRAP tended to increase (p=ns); whereas CO, SV and blood-O.sub.2-consumption tended to decrease (p=ns) with ADP infusion.

(51) Protocol 4—Response to Simultaneous ADP and Cangrelor Infusion.

(52) With simultaneous ADP and cangrelor infusion during normoxia, after the loading dose of cangrelor, MPAP first, transiently increased by 7.3±1.8 mmHg (p<0.05), compared to baseline, to reach a peak that was ˜66% of the peak ADP response without cangrelor (p<0.001), and then returned to a level not different (p=ns) from baseline, however, 7.4±1.5 mmHg lower (p<0.05) than the peak, after ˜4-7 min. The ˜4-7 min MPAP measurement was, hence, significantly lower (p<0.002) with simultaneous ADP and cangrelor infusion, as compared to with ADP infusion alone. During the same conditions, MAP first, transiently decreased (p<0.001) by 19.4±3.1 mmHg, compared to baseline, to reach a nadir at 64.9±3.4 mmHg, significantly higher (p<0.027) than the nadir response to ADP alone, and then, stabilized at a level 6.5±1.2 mmHg lower (p<0.01) than baseline, and 12.9±2.2 mmHg higher (p<0.001) than the nadir, after ˜4-7 min. The ˜4-7 min MAP measurement after simultaneous ADP and cangrelor infusion was, however, not different (p=ns) from the measurement with ADP infusion alone. Also, SVR decreased (p<0.024) by 3.2±1.2 WU, as compared to baseline, in response to simultaneous ADP and cangrelor infusion. However, the ˜4-7 min SVR measurement after simultaneous ADP and cangrelor infusion did not differ (p=ns) from the measurement with ADP infusion alone. During the same conditions; PVR, MRAP, PCWP, CO, HR, SV and blood-O.sub.2-consumption were unchanged (p=ns), although blood-O.sub.2-consumption tended to decrease (p=ns). Furthermore, the ˜4-7 min PVR and PCWP measurements after simultaneous ADP and cangrelor infusion were lower (p<0.005 and p<0.022, respectively) than the measurements with ADP infusion alone. Also, the ˜4-7 min SV measurement after simultaneous ADP and cangrelor infusion was higher (p<0.02) than the measurement with ADP infusion alone. Cangrelor infusion alone during normoxia did not alter (p=ns) any of the variables. There were neither any differences (p=ns) in between the baseline measurements of any parameters in protocol 3 and 4 or the ˜4-7 min measurements of MRAP, CO, HR and blood-O.sub.2-consumption with ADP infusion alone and simultaneous ADP and cangrelor infusion.

(53) Cangrelor temporarily attenuated acute HPV with a ˜12 and ˜14% MPAP decrease 10 and 30 min after cangrelor infusion was initiated, respectively, without affecting MAP, SVR and blood-O.sub.2-consumption. Cangrelor furthermore attenuated 34% of the MPAP peak and totally prevented the sustained MPAP and PVR increases induced by ADP infusion during normoxia. These data show that ADP is involved in modulating HPV and that ADP-induced pulmonary vasoconstriction is at least partially mediated by the P2Y.sub.12 receptor. P2Y.sub.12 receptor antagonism with cangrelor thus is potentially useful in attenuating hypoxia-induced pulmonary hypertension. Furthermore, the MAP decrease to ADP was attenuated with cangrelor, as was the PCWP increase and the trend for a SV decrease with ADP infusion alone.

(54) All documents, books, manuals, papers, patents, published patent applications, guides, abstracts, and other references cited herein are incorporated by reference in their entirety. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.