Phase 2 Healthy Volunteer Study to Evaluate the Ability of PRT064445 to Reverse the Effects of Several Blood Thinner Drugs on Laboratory Tests (Module 2 of 4)

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the ability of PRT064445 to reverse the effects of several blood thinner drugs on laboratory tests. The study also is evaluating the blood levels of PRT064445 given at different doses.

Detailed Description
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A randomized, double-blind, vehicle-controlled study to assess the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of intravenously administered PRT064445 after dosing to steady state with one of four direct/indirect factor Xa (fXa) inhibitors in healthy volunteers.

Official Title
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A Randomized, Double-Blind, Vehicle-Controlled Multiple Dose Study to Assess the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Intravenously Administered PRT064445 After Dosing to Steady State With One of Four Direct/Indirect fXa Inhibitors in Healthy Volunteers

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Combination Product: PRT064445/Rivaroxaban
* Combination Product: Placebo/Rivaroxaban
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy men or women between the ages of 18 and 45 years old Exclusion Criteria: History (including family history) or symptoms of, or risk factors for bleeding History (including family history) of or risk factors for a hypercoagulable or thrombotic condition Absolute/relative contraindication to anticoagulation or treatment with specific anticoagulants History of major surgery, severe trauma or bone fracture within 3 months prior to dosing; or planned surgery within 1 month after dosing.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: This study has four modules with a total of 21 cohorts, each module was reported and submitted separately. Module 1, NCT01758432 (54 subjects with 7 cohorts including placebo); Module 2, NCT03578146 (48 subjects with 6 cohorts including placebo); Module 3, NCT03551730 (27 subjects with 4 cohorts including placebo); Module 4, NCT03551743 (28 subjects with 4 cohorts including placebo)
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Module 2 (210 mg)<br>210 mg andexanet IV bolus administered over 7 minutes ( 30 mg/min) | Combination Product: PRT064445/Rivaroxaban<br> <br> * Other names: Andexanet;Combination Product: Placebo/Rivaroxaban<br> <br> |
| Experimental: Module 2 (420 mg)<br>420 mg andexanet IV bolus administered over 14 minutes ( 30 mg/min) | Combination Product: PRT064445/Rivaroxaban<br> <br> * Other names: Andexanet;Combination Product: Placebo/Rivaroxaban<br> <br> |
| Experimental: Module 2 (600 mg)<br>600 mg andexanet IV bolus administered over 20 minutes ( 30 mg/min) | Combination Product: PRT064445/Rivaroxaban<br> <br> * Other names: Andexanet;Combination Product: Placebo/Rivaroxaban<br> <br> |
| Experimental: Module 2 (720 mg bolus + 240 mg infusion)<br>720 mg IV bolus administered over 24 minutes [ 30 mg/min] followed by 240 mg continuous IV infusion [4 mg/min over 60 min) | Combination Product: PRT064445/Rivaroxaban<br> <br> * Other names: Andexanet;Combination Product: Placebo/Rivaroxaban<br> <br> |
| Experimental: Module 2 (800 mg bolus + 960 mg infusion)<br>800 mg IV bolus administered over 26.7 minutes [ 30 mg/min] followed by 960 mg continuous IV infusion [8 mg/min over 120 min] | Combination Product: PRT064445/Rivaroxaban<br> <br> * Other names: Andexanet;Combination Product: Placebo/Rivaroxaban<br> <br> |
| Experimental: Module 2 Placebo<br>Placebo administered intravenously (IV) as a bolus or a bolus followed by continuous fusion. | Drug: Placebo<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Efficacy: Percent Change From Baseline in Anti-fXa Activity at 2 Mins Following Andexanet/Placebo Administration | Anti-fXa activity was measured immediately prior to (Baseline) and at 2 mins following andexanet/placebo administration. Anti-fXa activity was measured using a commercial kit (Coamatic Heparin-82 33 9363, DiaPharma) | Baseline to 2 minutes following the end of andexanet/placebo administration | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Efficacy: Percent Change From Baseline in Thrombin Generation at 2 Mins Following Andexanet/Placebo Administration | Thrombin generation was measured immediately prior to (Baseline) and at 2 mins following andexanet/placebo administration. Thrombin generation was measured using a TF-initiated thrombin generation assay. | Baseline to 2 minutes following the end of andexanet/placebo administration | 
| Efficacy: Percent Change From Baseline in Unbound Rivaroaxaban Plasma Concentration at 2 Mins Following Andexanet/Placebo Administration | Unbound rivaroxaban concentrations was measured immediately prior to (Baseline) and at 2 mins following andexanet/placebo administration. Unbound plasma concentrations for rivaroxaban were determined by a rapid equilibrium dialysis method followed by Liquid Chromatography-Mass Spectometry assay. | Baseline to 2 minutes following the end of andexanet/placebo administration | 
| Andexanet Maximum Observed Plasma Concentration (Cmax) | Plasma concentrations of andexanet was determined using a validated method that involved analysis of citrated human plasma by an electrochemiluminescent assay. | Blood was collected at predose, 0.033, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5 and 14.5 hours postdose. | 
| Andexanet Area Under the Drug Concentration-time Curve From Time 0 Extrapolated to Infinity (AUC0-inf ) | Plasma concentrations of andexanet was determined using a validated method that involved analysis of citrated human plasma by an electrochemiluminescent assay. AUC0-inf was calculated using a non-compartmental approach | Blood was collected at predose, 0.033, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5 and 14.5 hours postdose. | 
| Andexanet Time of Maximum Observed Plasma Concentration (Tmax) | Plasma concentrations of andexanet was determined using a validated method that involved analysis of citrated human plasma by an electrochemiluminescent assay. Tmax was taken directly from the raw data. | Blood was collected at predose, 0.033, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5 and 14.5 hours postdose. | 
| Andexanet Apparent Terminal Elimination Half-life (t1/2) | Plasma concentrations of andexanet was determined using a validated method that involved analysis of citrated human plasma by an electrochemiluminescent assay. t1/2 was determined by linear regression of the log concentration on the terminal portion of the plasma concentration-time curve. | Blood was collected at predose, 0.033, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5 and 14.5 hours postdose. | 
| Andexanet Total Systemic Clearance (CL) | Plasma concentrations of andexanet was determined using a validated method that involved analysis of citrated human plasma by an electrochemiluminescent assay. CL was calculated using a non-compartmental approach, calculated as Dose/AUC0-inf | Blood was collected at predose, 0.033, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5 and 14.5 hours postdose. | 
| Andexanet Total Volume of Distribution (Vss) | Plasma concentrations of andexanet was determined using a validated method that involved analysis of citrated human plasma by an electrochemiluminescent assay. Vss was calculated using a non-compartmental approach. | Blood was collected at predose, 0.033, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5 and 14.5 hours postdose. |