scholarly journals A Phase 2 Randomized, Double-Blind, Placebo-Controlled Trial Demonstrating Reversal of Edoxaban-Induced Anticoagulation in Healthy Subjects By Andexanet Alfa (PRT064445), a Universal Antidote for Factor Xa (fXa) Inhibitors

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4269-4269 ◽  
Author(s):  
Mark Crowther ◽  
Gallia G. Levy ◽  
Genmin Lu ◽  
Janet Leeds ◽  
Joyce Lin ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Thrombin Generation ◽  
Controlled Study ◽  
Dependent Manner ◽  
Phase 2 ◽  
Double Blind ◽  
Double Blind Placebo ◽  
Equity Ownership ◽  
Andexanet Alfa ◽  
Inhibition Of Thrombin

Abstract Background: Direct fXa inhibitors appear to have similar or superior anticoagulant efficacy and safety relative to warfarin (and in some cases low molecular weight heparin) in the management of venous thromboembolism and stroke prevention in atrial fibrillation. However, they are limited by the lack of a specific antidote to reverse anticoagulation in cases of major bleeding episodes or prior to urgent/emergency surgery. Andexanet alfa (AnXa, PRT064445) is a modified, recombinant human fXa molecule that is catalytically inactive but retains high-affinity binding to direct and indirect fXa inhibitors, therefore acting as a decoy to bind and sequester fXa inhibitors. We previously reported Phase 2 data with apixaban, rivaroxaban and enoxaparin in healthy subjects and demonstrated that AnXa was able to rapidly and extensively reverse pharmacodynamic (PD) markers of anticoagulation. Here we report new clinical data demonstrating that AnXa rapidly reverses the PD markers of edoxaban-mediated anticoagulation – anti-fXa activity and inhibition of thrombin generation. Methods: This ongoing Phase 2, double-blind, placebo-controlled study is examining the reversal by AnXa of the anticoagulant activity of edoxaban (edox, the most recent fXa inhibitor for which an NDA/MAA was submitted) as well as its pharmacokinetics (PK) and safety profile in healthy subjects. Reversal of edox anticoagulation is being studied with up to 3 different dose cohorts/regimens of AnXa or placebo in a 6:3 ratio (i.e., 9 subjects per cohort). Edox is administered at an oral dose of 60 mg qd for 6 days and AnXa administered intravenously on Day 6, 3 hours after the last edox dose. PD and safety data are collected through Day 48 with PK data through Day 10. Results and Conclusions: We report here available data from the first 2 AnXa dose cohorts (600 mg bolus, n=9; 800 mg bolus followed by 8 mg/min infusion for 1 hr, n=9). Immediately after completion of the 600 mg or 800 mg bolus, anti-fXa activity decreased dose-dependently by 52% and 73%, respectively, from the pre-AnXa level, remained constant during the infusion, and returned to placebo levels by approximately 2 hours after treatment. In addition, edox-induced inhibition of thrombin generation and prolongation of clotting times were also reversed by AnXa in a dose-dependent manner. AnXa was well tolerated and there were no thrombotic events, serious, or severe adverse events. One subject was discontinued on Day 5 prior to AnXa dosing due to a vasovagal reaction. These data are consistent with previously reported results for other fXa inhibitors in that AnXa rapidly reverses PD markers of anticoagulation, restores normal thrombin generation, and is well tolerated. Disclosures Crowther: CSL Behring: Honoraria; Shire: Honoraria; Celgene: Honoraria; Bayer: Honoraria; AKP America: Consultancy; Leo Pharma: Consultancy, Honoraria, Research Funding; Janssen: Consultancy; Portola Pharmaceuticals, Inc.: Consultancy; The Heart and Stroke Foundation of Ontario: Career Investigator Award, Career Investigator Award Other. Levy:Portola Pharmaceuticals: Employment; University of Michigan: Patents & Royalties. Lu:Portola Pharmaceuticals Inc: Employment. Leeds:Portola Pharmaceuticals, Inc: Employment. Lin:Portola Pharmaceuticals, Inc.: Employment. Pratikhya:Portola Pharmaceuticals, Inc.: Employment. Conley:Portola Pharmaceuticals Inc: Employment; Portola Pharmaceuticals Inc: Equity Ownership. Connolly:Portola Pharmaceuticals Inc: Consultancy. Curnutte:Portola Pharmaceuticals, Inc.: Employment, Equity Ownership; Sea Lane Biotechnologies: Consultancy; 3-V Biosciences: Equity Ownership.

A Phase 2 Randomized, Double-Blind, Placebo-Controlled Trial Demonstrating Reversal Of Rivaroxaban-Induced Anticoagulation In Healthy Subjects By Andexanet Alfa (PRT064445), An Antidote For Fxa Inhibitors

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3636-3636 ◽  
Author(s):  
Crowther Mark ◽  
Mathur Vandana ◽  
Kitt Michael ◽  
Lu Genmin ◽  
Pamela B. Conley ◽  
...  
Keyword(s):  
Adverse Events ◽  
Healthy Subjects ◽  
Controlled Study ◽  
Pharmacokinetic Data ◽  
Phase 2 ◽  
Employment Equity ◽  
Double Blind ◽  
Double Blind Placebo ◽  
Equity Ownership ◽  
Andexanet Alfa

Abstract Background Direct factor Xa inhibitors have demonstrated compelling anticoagulant efficacy and/or safety profiles across multiple diverse patient populations. A specific antidote to reverse anticoagulation during episodes of serious uncontrolled bleeding or before urgent/emergent surgery is lacking. Andexanet alfa (proposed INN)(AnXa, PRT064445) is a modified, recombinant human fXa molecule that is catalytically inactive but retains high-affinity binding to direct fXa inhibitors. It thus acts as a decoy to reverse fXa inhibitor-mediated anticoagulation in preclinical and early clinical studies. Methods This ongoing Phase 2, double-blind, placebo-controlled study is examining the reversal by AnXa of the anticoagulant activity of rivaroxaban (riva), as well as the pharmacokinetics and safety in healthy subjects. Reversal of riva anticoagulation will be studied with up to 6 different dose cohorts/ regimens of AnXa or placebo in a 6:3 ratio (i.e., 9 subjects per cohort). Riva is administered at an oral dose of 20 mg qd for 6 days and AnXa administered intravenously on Day 6, 3 hours after the last riva dose – the approximate time of maximum riva concentration (mean ± SD: 0.64 ± 0.22 mM, n=18). Pharmacodynamic and safety data are collected through Day 48 with pharmacokinetic data through Day 10. Results We report here available data from the first 2 AnXa dose cohorts (210 mg and 420 mg, n =18). Immediately after completion of the 210 mg and 420 mg doses, anti-fXa activity decreased dose-dependently by 20% and 53%, respectively, from the pre-AnXa level and returned to placebo levels by approximately 2 hours after treatment (Figure). In parallel, the plasma concentrations of unbound riva were decreased by 32% and 51%, respectively, relative to pre-AnXa values. In addition, riva-induced inhibition of thrombin generation and prolongation of both prothrombin time and activated clotting time were also rapidly partially reversed by AnXa in a dose-dependent manner. At 2 minutes after AnXa administration, the molar ratio of AnXa to total plasma riva was 0.8 for the 210 mg dose (1.2 µM/1.6 µM, respectively) and 1.2 for the 420 mg dose (2.6 µM/2.1 µM, respectively). AnXa infusion was not associated with increases in prothrombin fragments F1+2, thrombin-antithrombin, or D-dimer (all values were within normal ranges). As expected, tissue factor pathway inhibitor activity decreased due to its binding to AnXa. AnXa was well tolerated and there were no thrombotic events, serious, or severe adverse events. Adverse events occurring in 1 or more AnXa or placebo recipients included infusion-related reactions (n = 3, all mild in severity) and post-procedural hematoma, headache, or postural dizziness (n = 2 each). Summary/Conclusions Results from this ongoing clinical trial demonstrate that AnXa is able to dose-dependently partially reverse the anticoagulant effects of rivaroxaban, as assessed by pharmacodynamic markers, in healthy subjects. These data are consistent with previously reported results with apixaban in that AnXa sequesters rivaroxaban and apixaban in a similar stoichiometric manner. Additional data with higher doses of AnXa will also be presented. AnXa is well-tolerated and a potentially promising, universal antidote for fXa inhibitors. Disclosures: Mark: Portola Pharmaceuticals: Consultancy. Off Label Use: The use of PRT064445 as an antidote for reversal of anticoagulation from direct and indirect fXa inhibitors is investigational. Vandana:Portola Pharmaceuticals: Consultancy. Michael:Portola Pharmaceuticals: Employment, Equity Ownership. Genmin:Portola Pharmaceuticals: Employment, Equity Ownership. Conley:Portola Pharmaceuticals: Employment, Equity Ownership. Stanley:Portola Pharmaceuticals: Employment, Equity Ownership. Castillo:Portola Pharmaceuticals: Employment, Equity Ownership. Hutchaleelaha:Portola Pharmaceuticals: Consultancy. Karbarz:Portola Pharmaceuticals: Employment. Lin:Portola Pharmaceuticals: Employment. Barron:Portola Pharmaceuticals: Employment. Russell:Portola Pharmaceuticals: Employment. Levy:Portola Pharmaceuticals: Employment. Connolly:Portola Pharmaceuticals: Consultancy. Curnutte:Portola Pharmaceuticals: Employment, Equity Ownership.

scholarly journals Anti‐IL‐7 receptor α monoclonal antibody (GSK2618960) in healthy subjects – a randomized, double‐blind, placebo‐controlled study

2018 ◽  
Vol 85 (2) ◽  
pp. 304-315 ◽  
Author(s):  
Joanne Ellis ◽  
Andre Maurik ◽  
Lea Fortunato ◽  
Sophie Gisbert ◽  
Keguan Chen ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Healthy Subjects ◽  
Controlled Study ◽  
Double Blind ◽  
Double Blind Placebo

Abstract 212: Andexanet Alfa, a Universal Antidote for Reversal of Anticoagulation of Factor Xa Inhibitors in Healthy Human Volunteers

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Mark Crowther ◽  
Alexander M Gold ◽  
Genmin Lu ◽  
Janet M Leeds ◽  
Brian L Wiens ◽  
...  
Keyword(s):  
Healthy Subjects ◽  
Statistical Significance ◽  
Factor Xa ◽  
Clinical Results ◽  
Phase 2 ◽  
Healthy Human ◽  
Serious Adverse Events ◽  
Double Blind ◽  
Secondary Endpoints ◽  
Andexanet Alfa

Introduction: Andexanet alfa (AnXa) is a recombinant modified fXa molecule that acts as a specific antidote for fXa inhibitors. We report clinical results in healthy subjects anticoagulated with apixaban (apix), rivaroxaban (riva), edoxaban (edox), or enoxaparin (enox), demonstrating rapid and sustained reversal of anticoagulation following administration of AnXa. Methods: These were Phase 2/3 randomized, double-blind, placebo-controlled studies in healthy subjects. In Phase 2, about153 subjects age18 - 45 were given one of the fXa inhibitors (apix 5 mg BID, riva 20 mg QD, edox 60 mg QD or enox 40 mg QD) for 6 days. AnXa or placebo (3:1 randomization) was given IV on Day 6, 3hrs after the last inhibitor dose (∼inhibitor Cmax). Safety was followed through Day 48. A range of AnXa doses (bolus or bolus+infusion) was evaluated by correction of biomarkers (anti-fXa activity, free inhibitor concentrations and thrombin generation (TG)). In Phase 3 (ANNEXA™), older subjects age 50 to 75 were dosed with apix (5 mg BID) or riva (20 mg QD) for 4 days. ANNEXA™-A had 63 subjects treated with apix. AnXa (400 mg bolus; 400 mg bolus plus 4 mg/min x 2hr infusion) or placebo (3:1 randomization) was given on Day 4, 3 hrs after the last apix dose. ANNEXA™-R had 82 subjects treated with riva. AnXa (800 mg bolus; 800 mg bolus plus 8 mg/min x 2hr infusion) or placebo (2:1) was given on Day 4, 4 hrs after the last riva dose. Safety was followed through Day 43. Results: About 298 healthy subjects were enrolled in the studies. AnXa demonstrated rapid and sustained reversal of both direct and indirect fXa inhibitors as measured by correction of biomarkers. The ANNEXA™ studies confirmed findings from Phase 2, and met all primary (reversal of anti-fXa) and secondary endpoints (reduction of free inhibitor concentration and restoration of TG) with high statistical significance. AnXa was well-tolerated with no serious adverse events, thrombotic events, or antibodies to fX or fXa reported. Conclusion: AnXa treatment results in rapid and sustained reversal of anticoagulation of fXa inhibitors. A Phase 3b/4 confirmatory study (ANNEXA-4) in patients with acute major bleeds is ongoing.

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