Blood factor monitoring assay and uses thereof
The present disclosure provides methods and compositions for diagnosing and treating subject having a bleeding disorder. The disclosed methods comprise contacting a sample, e.g., a blood or plasma sample obtained from the patient, with an activation mixture comprising an activated coagulation factor and a phospholipid mixture, wherein the activation mixture is dried onto a solid substrate. Also provided is a global hemostasis test based on the integration of clotting time (Ct) and pharmacokinetics data. The methods and compositions presented can be applied to point-of-care diagnostic systems.
1. A method of modifying a hemophilia B treatment in a subject who has hemophilia B, comprising:
(a) measuring the time between
(i) contacting of a sample obtained from the subject with an activation mixture consisting essentially of an activated Factor XI (FXIa) and a phospholipid mixture, and
(ii) onset of clotting, thereby calculating a clotting time (Ct);
wherein the Ct is used to determine a pharmacokinetic (PK) parameter of Factor IX,
wherein the PK parameter is terminal half-life (HL) or time to trough (T),
wherein HL is calculated according to the formula:
HL=− 0.693×( T 2 −T 1 )× A /( Ct 1 −Ct 2 ) [Formula II]
and wherein T is calculated according to the formula:
T=− 1.44× HL /( A ×( Ct measured −Ct trough ) [Formula III]
wherein, for Factor IX, A is a constant value corresponding to the slope of a Ct versus Factor IX concentration dose-response, T 1 and T 2 are times at which Ct is measured, and Ct 1 and Ct 2 are Ct values measured at T 1 and T 2 , respectively, Ct measured is Ct measured at certain time point, and Ct trough is patient-specific clotting time at trough; and
(b) modifying the hemophilia B treatment for the subject based on the PK parameter, wherein the PK parameter correlates with a therapeutically efficacious treatment,
thereby administering an optimized hemophilia B treatment to the subject, wherein the treatment is adjusted;
wherein the measurement is carried out in a point of care test system, and
wherein the phospholipid mixture comprises 75 mole-% of phosphatidylcholine, 20 mole-% of phosphatidylserine, and 5 mole-% of phosphatidylglycerol.
2. The method of claim 1 , wherein the sample is selected from the group consisting of whole blood, citrated or equivalently stabilized blood, plasma, and other fluid sample containing or suspected of containing Factor IX.
3. The method of claim 1 , wherein the sample is decalcified.
4. The method of claim 1 , wherein the subject has received prior Factor IX treatment, but the treatment has been discontinued for a time period sufficient to deplete the Factor IX from the subject's blood.
5. The method of claim 1 , wherein the Factor IX is rFIXFc.
6. The method of claim 1 , wherein the activation mixture consists essentially of 80% of Factor XIa suspension and 20% of the phospholipid mixture.
7. The method of claim 6 , wherein the activation mixture is dried onto a solid substrate.
8. The method of claim 1 , wherein the activation mixture does not contain an additional coagulation factor activator or inhibitor.
9. A method of modifying a hemophilia B treatment in a subject who has hemophilia B, comprising:
(a) measuring the time between
(i) contacting of a sample obtained from the subject with an activation mixture consisting essentially of 80% of activated Factor XI (FXIa) and 20% of a phospholipid mixture comprising 75 mole-% of phosphatidylcholine, 20 mole-% of phosphatidylserine, and 5 mole-% of phosphatidylglycerol, and
(ii) onset of clotting, thereby calculating a clotting time (Ct);
wherein the Ct is used to determine a pharmacokinetic (PK) parameter of Factor IX,
wherein the PK parameter is terminal half-life (HL) or time to trough (T),
wherein HL is calculated according to the formula:
HL=− 0.693×( T 2 −T 1 )× A /( Ct 1 −Ct 2 ) [Formula II]
and wherein T is calculated according to the formula:
T=− 1.44× HL /( A ×( Ct measured −Ct trough ) [Formula III]
wherein, for Factor IX, A is a constant value corresponding to the slope of a Ct versus Factor IX concentration dose-response, T 1 and T 2 are times at which Ct is measured, and Ct 1 and Ct 2 are Ct values measured at T 1 and T 2 , respectively, Ct measured is Ct measured at certain time point, and Ct trough is patient-specific clotting time at trough; and
(b) modifying the hemophilia B treatment for the subject based on the PK parameter, wherein the PK parameter correlates with a therapeutically efficacious treatment,
thereby administering an optimized hemophilia B treatment to the subject, wherein the treatment is adjusted;
wherein the measurement is carried out in a point of care test system, and
wherein the Factor IX is rFIXFc,
wherein the activation mixture is dried onto a solid substrate, and
wherein the activation mixture does not contain an additional coagulation factor activator or inhibitor.