Controlled platelet activation to monitor therapy of ADP antagonists
View Patent ↗A method is provided of determining whether an individual has reduced ability to form platelet thrombi due to inhibition of platelet activation initiation, signal transduction and/or GPIIb/IIIa blockade. A blood sample is obtained from the individual being assessed. The blood sample is mixed in combination with 1) an anticoagulant; 2) sufficient buffer to maintain the pH and salt concentration of the anticoagulated blood within a range suitable for platelet aggregation; 3) a platelet GPIIb/IIIa receptor ligand immobilized on a solid surface; 4) one or more agents to enhance a signal transduction pathway and 5) a receptor activator. The combination is incubated under conditions for agglutinating particles. Platelet-mediated agglutination is assessed in the agitated mixture. The absence of agglutination indicates that the individual has a reduced ability to form platelet thrombi.
1. A method for determining a patient's response to a P2Y12 antagonist, comprising the steps of:
providing a platelet-containing blood sample from a patient an individual treated with a P2Y12 antagonist;
contacting the platelet-containing blood sample with adenosine diphosphate (ADP), prostaglandin E1 (PGE1) and particles comprising a GPIIb/IIIa receptor ligand, under conditions suitable for platelet aggregation as measured by agglutination of the particles,
measuring the level of particle agglutination;
determining the level of platelet aggregation as measured by the level of particle agglutination;
wherein a reduced level of agglutination, as compared to a control level, indicates an effective response to said P2Y12 antagonist treatment.
2. The method of claim 1 , wherein said P2Y12 antagonist is a thienopyridine.
3. The method of claim 2 , wherein said thienopyridine is clopidogrel.
4. The method of claim 2 , wherein said thienopyridine is ticlopidine.
5. The method of claim 1 , wherein platelet-containing blood sample is from a patient treated with a P2Y12 antagonist and aspirin.
6. The method of claim 1 , wherein the platelet-containing blood sample is contacted with PGE1 at a concentration of 20 nM to 25 nM.
7. The method of claim 1 , wherein said platelet-containing blood sample is a whole blood sample.
8. The method of claim 1 , wherein said platelet-containing blood sample is a plasma sample.
9. The method of claim 8 , wherein said plasma sample is a platelet rich plasma sample.
10. The method of claim 1 , wherein the level of platelet aggregation is determined in an aqueous medium comprising the blood sample.
11. The method of claim 1 , wherein the blood sample volume is from 30 μL to 5000 μL.