UNIT DOSE FORMULATIONS AND METHODS OF TREATING AND PREVENTING THROMBOSIS WITH THROMBOXANE RECEPTOR ANTAGONISTS
The present invention provides new methods of treating thrombosis and cardiovascular diseases using of antithrombotic agents, as well as methods of determining therapeutically effective amounts of antithrombotic agents and unit dose formulations thereof.
1 . A method for inhibiting platelet aggregation in a patient in need thereof, comprising administering to a patient in need thereof a therapeutic concentration of an antithrombotic agent, wherein said therapeutic concentration is determined by a method comprising:
(a) contacting a blood sample obtained from a mammal with a physiological platelet agonist in an amount sufficient to induce platelet aggregation in the blood sample and measuring a first amount of platelet aggregation; and
(b) subsequently contacting the blood sample with a plasma concentration of an antithrombotic agent and measuring a second amount of platelet aggregation in the blood sample, wherein if the second amount of platelet aggregation is at least 25% lower than the first amount of platelet aggregation, the plasma concentration of the antithrombotic agent is a therapeutically effective plasma concentration.
2 . The method of claim 1 , wherein the physiological platelet agonist is collagen.
3 . The method of claim 1 , further comprising anticoagulating the blood sample prior to contacting the blood sample with the physiological platelet agonist.
4 . The method of claim 1 , wherein the antithrombotic agent is a thromboxane receptor antagonist.
5 . The method of claim 4 , wherein the thromboxane receptor antagonist is ifetroban.
6 . The method of claim 1 , wherein the first amount and second amount of platelet aggregation is measured by light transmittance aggregometry.
7 . The method of claim 2 , wherein the first amount and second amount of platelet aggregation is measured using a real time perfusion chamber.
8 . A method of inhibiting aggregation of platelets, comprising contacting platelets with ifetroban at a concentration greater than 100 nM.
9 . A method of treating or preventing thrombosis in a patient, comprising administering to the patient an amount of ifetroban sufficient to achieve a plasma concentration greater than 100 nM for at least 24 hours.
10 . The method of claim 9 , wherein the amount of ifetroban is between 1 and 10 mg/kg/day.
11 . The method of claim 9 , wherein the amount is sufficient to achieve a plasma concentration greater than or equal to 350 nM for at least 12 hours.
12 . The method of claim 9 , wherein the amount is sufficient to achieve a plasma concentration greater than or equal to 350 nM for at least 24 hours.
13 . The method of claim 12 , wherein the amount of ifetroban is between 6 and 10 mg/kg/day.
14 . A method of treating or preventing thrombosis in a patient, comprising administering a therapeutically effective plasma concentration of an antithrombotic agent to the patient, wherein the therapeutically effective plasma concentration is determined by a method comprising:
(a) contacting a blood sample obtained from a mammal with a physiological platelet agonist in an amount sufficient to induce platelet aggregation in the blood sample and measuring a first amount of platelet aggregation; and
(b) subsequently contacting the blood sample with a plasma concentration of an antithrombotic agent and measuring a second amount of platelet aggregation in the blood sample, wherein if the second amount of platelet aggregation is at least 25% lower than the first amount of platelet aggregation, the plasma concentration of the antithrombotic agent is a therapeutically effective plasma concentration.
15 . The method of claim 14 , wherein the physiological platelet agonist is collagen.
16 . The method of claim 14 , further comprising anticoagulating the blood sample prior to contacting the blood sample with the physiological platelet agonist.
17 . The method of claim 14 , wherein the antithrombotic agent is a thromboxane receptor antagonist.
18 . The method of claim 17 , wherein the thromboxane receptor antagonist is ifetroban.
19 . The method of claim 14 , wherein the first amount and second amount of platelet aggregation is measured by light transmittance aggregometry.
20 . The method of claim 14 , wherein the first amount and second amount of platelet aggregation is measured using a real time perfusion chamber.
21 . A unit dose formulation of ifetroban, comprising a pharmaceutically acceptable carrier and an amount of ifetroban sufficient to maintain a plasma concentration of 250 nM for at least 24 hours.
22 . The unit dose formulation of claim 21 , wherein the amount of ifetroban is sufficient to maintain a plasma concentration of 350 nM for at least 24 hours.
23 . The unit dose formulation of claim 21 , wherein the formulation is adapted for once a day administration and the amount of ifetroban is a dose between 6-10 mg/kg.
24 . The unit dose formulation of claim 21 , wherein the formulation is adapted for twice a day administration and the amount of ifetroban is a dose between 3-5 mg/kg.
25 . A method for determining an effective concentration of an antithrombotic agent for inhibiting aggregation of mammalian platelets, comprising:
(a) contacting a blood sample obtained from a mammal with a physiological platelet agonist in an amount sufficient to induce platelet aggregation in the blood sample and measuring a first amount of platelet aggregation; and
(b) subsequently contacting the blood sample with a plasma concentration of the antithrombotic agent and measuring a second amount of platelet aggregation in the blood sample, wherein, if the second amount of platelet aggregation is at least 25% lower than the first amount of platelet aggregation, the plasma concentration is an effective concentration of the antithrombotic agent for inhibiting aggregation of mammalian platelets.
26 . The method of claim 25 , wherein the physiological platelet agonist is selected from the group consisting of: collagen, epinephrine, and ADP.
27 . The method of claim 25 , further comprising anticoagulating the blood sample prior to contacting the blood sample with the physiological platelet agonist.
28 . The method of claim 25 , wherein the antithrombotic agent is a thromboxane receptor antagonist.
29 . The method of claim 28 , wherein the thromboxane receptor antagonist is ifetroban.
30 . A method of treating or preventing thrombosis in a patient, comprising providing to a patient an amount of ifetroban sufficient to achieve a steady-state blood plasma concentration of at least 350 nM for some time.
31 . The method of claim 31 , wherein the amount of ifetroban is sufficient to achieve a steady-state blood plasma concentration in the range of 350 nM and 1000 nM for some time.
32 . A method of treating or preventing thrombosis in a patient, comprising providing to a patient an amount of ifetroban sufficient to achieve a blood plasma concentration having a Cmax in the range of 1500 to 2500 ng/mL.
33 . A method of treating or preventing thrombosis in a patient, comprising providing to a patient amount of ifetroban sufficient to achieve a total blood plasma concentration having a mean trough concentration of about 154 ng/mL.
34 . A method of treating or preventing thrombosis in a patient, comprising administering to a patient an amount of ifetroban sufficient to achieve a total blood plasma concentration having a peak to trough concentration ratio of 15 or less.
35 . A method of treating or preventing a cardiovascular disease or disorder in a patient, comprising providing to the patient ifetroban in an amount sufficient to achieve a blood plasma concentration greater than 100 nM for at least 12 hours.
36 . The method of claim 35 , wherein the plasma concentration is greater than 100 nM for at least 12 hours.
37 . The method of claim 35 , wherein the amount is sufficient to achieve a plasma concentration greater than or equal to 350 nM for at least 12 hours.
38 . The method of claim 37 , wherein the amount is sufficient to achieve a plasma concentration greater than or equal to 350 nM for at least 24 hours.
39 . The method of claim 35 , wherein the amount of ifetroban is between 1 and 10 mg/kg/day.
40 . The method of claim 39 , wherein the amount of ifetroban is between 6 and 10 mg/kg/day.
41 . The method of claim 35 , wherein the cardiovascular disease or disorder is selected from the group consisting of: myocardial infarction, thrombotic stroke, atherosclerotic disease, unstable angina, refractory angina, transient ischemic attacks, embolic stroke, disseminated intravascular coagulation, septic shock, deep venous thrombosis, pulmonary embolism, reocclusion, restenosis, pulmonary embolism, occlusive coronary thrombus, complications resulting from thrombolytic therapy, percutaneous transluminal coronary angioplasty, or coronary artery bypass grafts, pulmonary hypertension, and intravascular thrombosis.