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Background:  Andexanet alfa (andexanet) is approved for specific anticoagulation reversal in patients with life-threatening or uncontrolled bleeding during treatment with rivaroxaban or apixaban. There is limited experience with andexanet in patients with acute bleeding on edoxaban., Methods:  Patients with acute major bleeding within 18 hours of edoxaban intake were prospectively enrolled. Patients received a bolus and 2-hour follow-on infusion of andexanet. The co-primary efficacy outcomes were change in antifactor Xa activity and the percentage of patients achieving excellent or good hemostasis, 12 hours after andexanet treatment. Efficacy was analyzed in patients with confirmed major bleeding and baseline antifactor Xa activity ≥40 ng/mL. Safety was analyzed in all patients., Results:  Thirty-six patients (mean age: 82 years, 61.1% male and 91.7% with atrial fibrillation) with acute major bleeding on edoxaban received andexanet. The primary site of bleeding was intracranial in 29 patients (80.6%). In the efficacy population ( n  = 28), median antifactor Xa activity decreased from 121.1 (interquartile range [IQR]: 70.3-202.4) ng/mL at baseline to 24.0 (IQR: 77.7-83.7) ng/mL at the end of andexanet bolus (median decrease: 68.9%, 95% confidence interval [CI]: 56.1-77.7%). Excellent or good hemostasis at 12 hours was achieved in 78.6% (95% CI: 59.0-91.7%) of patients. Within 30 days, four patients (11.1%) experienced a thrombotic event and four others (11.1%) died., Conclusion:  In patients with acute major bleeding on edoxaban, andexanet significantly decreased antifactor Xa activity. Hemostatic efficacy was similar to that observed in patients with bleeding on rivaroxaban or apixaban. Thrombotic events occurred at a rate expected in such patients., Competing Interests: A.P.B and L.X. have nothing to report. J.W.E. reports honoraria and/or research grants from AstraZeneca, Bayer, Boehringer Ingelheim, Bristol-Myers Squibb, Daiichi Sankyo Inc., Pfizer, and Servier. S.M. reports grant support from Daiichi Sankyo Inc., Bayer, and Aspen Pharma; serving on advisory boards for Bayer, Bristol-Myers Squibb/Pfizer, Boehringer Ingelheim, and Portola; receiving lecture fees from Portola; and serving on an adjudication committee for AbbVie. T.J.M. reports executive/steering committee payments for ANNEXA-I and ENRICH-AF studies from PHRI/McMaster University; consulting income from CSL Behring; and grants from NHLBI and Genentech. M.C. reports serving on a data and safety monitoring board for Bayer; receiving personal funding or serving on advisory boards for Bristol Myers Squibb Canada, CSL Behring, Servier Canada, Asahi Kasei, Precision Biologics, and Hemostasis Reference Laboratory; preparation of educational material and/or presentations and/or moderation of sessions for Pfizer, Alexion, CSL Behring, and Diagnostica Stago; and individual stock ownership for Alnylam. P.Y. reports former employment with Portola Pharmaceuticals Inc., now Alexion, AstraZeneca Rare Disease. P.C. reports former employment with Portola Pharmaceuticals Inc., now Alexion, AstraZeneca Rare Disease. G.L. reports employment with Portola Pharmaceuticals Inc., now Alexion, AstraZeneca Rare Disease. S.J.C. reports institutional research grants and honoraria from Boehringer Ingelheim, Portola/Alexion Pharmaceuticals, Bristol-Myers Squibb/Pfizer, Bayer, and Daiichi Sankyo Inc., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Objective: Compare 30-day mortality among patients receiving the specific reversal agent andexanet alfa versus replacement prothrombin complex concentrate (PCC) in the management of direct-acting oral anticoagulant (DOAC)-related bleeds., Methods: Two patient-level datasets were used: ANNEXA-4, a prospective, single-arm trial of patients taking apixaban or rivaroxaban who received andexanet alfa and ORANGE, a prospective, observational study of anticoagulated patients in UK hospitals, some of whom received PCC. Patients were propensity score matched based on demographic and clinical characteristics. Subgroup analyses were performed by bleed type (intracranial hemorrhage [ICH], gastrointestinal [GI], other). Relative risk (RR) of all-cause 30-day mortality was calculated., Results: 322 ANNEXA-4 patients treated with andexanet alfa (mean age = 77.7 years; 64.9% ICH) were matched with 88 ORANGE patients treated with PCC (mean age = 74.9 years, 67.1% ICH). Adjusted 30-day mortality for patients treated with andexanet alfa (14.6%) was lower than patients treated with PCC (34.1%; RR, 0.43; 95% CI, 0.29-0.63). In the ICH subgroup, patients treated with andexanet alfa had lower mortality (15.3%) than patients treated with PCC (48.9%; RR, 0.31; 95% CI, 0.20-0.48). Mortality risk was lowest for patients in the GI subgroup but did not differ significantly by treatment (12.2% for andexanet alfa vs 25.0% for PCC; RR, 0.49; 95% CI, 0.21-1.16)., Conclusions: In this propensity score-matched comparison across 2 independent datasets, adjusted 30-day mortality rates were lower for patients treated with andexanet alfa than in matched patients receiving PCC. This indirect comparison was limited in that it could not account for several highly predictive variables including GCS score, hematoma volume, and expected survival. Further research is warranted to confirm the mortality differences between reversal/replacement agents for DOAC-related bleeding., Competing Interests: ATC has received fees for serving on an adjudication committee from Boehringer Ingelheim and AbbVie; grant support and fees for serving on committees from Bristol Myers Squibb, Daiichi Sankyo and Pfizer; consulting fees from Janssen, Portola Pharmaceuticals and Ono Pharmaceuticals; fees for serving on a steering committee and consulting fees from Bayer, and travel support to present this work at the American College of Cardiology annual meeting. ML and AC are employed by FIECON, which performed this analysis at Portola's request and received payment for their contributions to the statistical analysis and drafting the manuscript. SJC has received grant support and consulting fees from Portola Pharmaceuticals, Bristol Myers Squibb, Bayer, and Daiichi Sankyo. PY and JC were employed by and held stock options in Portola Pharmaceuticals at the time of this work. RA has received grant support and consulting fees from Portola Pharmaceuticals, Bristol Myers Squibb, Bayer, Daiichi Sankyo, and Pfizer. PMC has received fees for serving on a committee from Portola Pharmaceuticals. JT and LG report no conflicts of interest., (© 2022 The Authors. JACEP Open published by Wiley Periodicals LLC on behalf of American College of Emergency Physicians.)

Background and Purpose: It is unestablished whether andexanet alfa, compared with guideline-based usual care including prothrombin complex concentrates, is associated with reduced hematoma expansion (HE) and mortality in patients with factor-Xa inhibitor-related intracerebral hemorrhage (ICH). We compared the occurrence of HE and clinical outcomes in patients treated either with andexanet alfa or with usual care during the acute phase of factor-Xa inhibitor-related ICH., Methods: Data were extracted from the multicenter, prospective, single-arm ANNEXA-4 trial (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors) and a multicenter observational cohort study, RETRACE-II (German-Wide Multicenter Analysis of Oral Anticoagulant-Associated Intracerebral Hemorrhage - Part Two). HE was based on computed tomography scans performed within 36 hours from baseline imaging. Inverse probability of treatment weighting was performed to adjust for baseline comorbidities and ICH severity. Patients presenting with atraumatic ICH while receiving apixaban or rivaroxaban within 18 hours of admission were included. Patients with secondary ICH or not fulfilling the inclusion criteria for the ANNEXA-4 trial were excluded. We compared ANNEXA-4 patients, who received andexanet alfa for hemostatic treatment, with RETRACE-II patients who were treated with usual care, primarily administration of prothrombin complex concentrates. Primary outcome was rate of HE defined as relative increase of ≥35%. Secondary outcomes comprised mean absolute change in hematoma volume, as well as in-hospital mortality and functional outcome., Results: Overall, 182 patients with factor-Xa inhibitor-related ICH (85 receiving andexanet alfa versus 97 receiving usual care) were selected for analysis. There were no relevant differences regarding demographic or clinical characteristics between both groups. HE occurred in 11 of 80 (14%) andexanet alfa patients compared with 21 of 67 (36%) usual care patients (adjusted relative risk, 0.40 [95% CI, 0.20-0.78]; P =0.005), with a reduction in mean overall hematoma volume change of 7 mL. There were no statistically significant differences among in-hospital mortality or functional outcomes. Sensitivity analysis including only usual care patients receiving prothrombin complex concentrates demonstrated consistent results., Conclusions: As compared with usual care, andexanet alfa was associated with a lower rate of HE in atraumatic factor-Xa inhibitor-related ICH, however, without translating into significantly improved clinical outcomes. A comparative trial is needed to confirm the benefit on limiting HE and to explore clinical outcomes across patient subgroups and by time to treatment. Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT02329327 and NCT03093233.

Background: Lack of data on balancing bleeding and thrombosis risk causes uncertainty about restarting anticoagulants after major bleeding. Anticoagulant reversal trials offer prospectively gathered data after major bleeding with well-documented safety events and restarting behavior., Objectives: To examine the relationship of restarting anticoagulation with thrombosis, rebleeding, and death., Methods: This is a posthoc analysis of a prospective factor Xa inhibitor reversal study at 63 centers in North America and Europe. We compared outcomes of restarted patients with those not restarted using landmark and time-dependent Cox proportional hazards models. Outcomes included thrombotic and bleeding events and death and a composite of all three., Results: Of 352 patients enrolled, oral anticoagulation was restarted in 100 (28%) during 30-day follow-up. Thirty-four (9.7%) had thrombotic events, 15 (4.3%) had bleeding events (after day 3), and 49 (14%) died. In the landmark analysis comparing patients restarted within 14 days to those not, restarting was associated with decreased thrombotic events (hazard ratio [HR] = 0.112; 95% confidence interval [CI]: 0.001-0.944; p  = 0.043) and increased rebleeding (HR = 8.39; 95% CI: 1.13-62.29; p  = 0.037). The time-dependent Cox model showed evidence for a reduction in a composite (thrombotic events, bleeding, and death) attempting to capture net benefit (HR = 0.384; 95% CI: 0.161-0.915; p  = 0.031)., Conclusion: This analysis provides modest evidence that restarting anticoagulation in factor Xa inhibitor-associated major bleeding patients is correlated with reduced risk of thrombotic events and increased risk of rebleeding. There is low-level evidence of net benefit for restarting. A randomized trial of restarting would be appropriate., Competing Interests: T.J.M.: CSL Behring: consulting; Portola: grant support, steering committee; Octapharma: steering committee. B.K.: none. P.Y.: Portola: employee. S.M.: Daiichi Sankyo, Bayer, Aspen Pharma: grant support; Bristol Myers Squibb/Pfizer, Boehringer Ingelheim, Portola: advisory board; Portola: lecture fees; AbbVie: adjudication committee. J.B.-W.: Bayer, Daiichi Sankyo: grant support, lecture fees, advisory board fees; Pfizer: grant support; Portola: lecture fees, advisory board fees. J.W.E.: AstraZeneca, Bayer, Boehringer Ingelheim, Bristol Myers Squibb/Pfizer, Daiichi Sankyo, Eli Lilly, GlaxoSmithKline, Janssen, Sanofi-Aventis: grant support, honoraria. M.C.: Bristol Myers Squibb Canada, Asahi Kasei, Servier Canada, Precision Biologics, Hemostasis Reference Laboratory, CSL Behring: advisory board; Alexion, Pfizer, CSL Behring, Diagnostica Stago: educational funding; Bayer, Leo Pharma: grant support; Daiichi Sankyo, Bayer, Octapharma: data safety monitoring board. L.X.: None. P.V.: Bayer Healthcare, Boehringer Ingelheim, Daiichi Sankyo, Pfizer, Bristol Myers Squibb, Leo Pharma: grant support, consulting, lecture fees; Boehringer Ingelheim: adjudication committee; Anthos, Janssen, Portola: consulting. D.M.S.: Bayer, Bristol Myers Squibb/Pfizer, Servier Canada, Novartis, Leo Pharma, Aspen Pharma, Portola: consulting. S.J.C.: Portola, Bristol Myers Squibb, Bayer, Daiichi Sankyo: grant support, consulting; Javelin: consulting., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Background and Purpose: Andexanet alfa is a recombinant modified human FXa (factor Xa) developed to reverse FXa inhibition from anticoagulants. Hemostatic efficacy and reversal of anti-FXa activity with andexanet were assessed in patients from the ANNEXA-4 study (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of FXa Inhibitors) with intracranial hemorrhage (ICrH)., Methods: ANNEXA-4 was a single-arm study evaluating andexanet in patients presenting with major bleeding ≤18 hours after taking an FXa inhibitor. Patients received a bolus plus 2-hour infusion of andexanet. Brain imaging in patients with ICrH was performed at baseline and at 1 and 12 hours postandexanet infusion. Coprimary efficacy outcomes were change in anti-FXa activity and hemostatic efficacy at 12 hours (excellent/good efficacy defined as ≤35% increase in hemorrhage volume/thickness). Safety outcomes included occurrence of thrombotic events and death at 30 days., Results: A total of 227 patients with ICrH were included in the safety population (51.5% male; mean age 79.3 years) and 171 in the efficacy population (99 spontaneous and 72 traumatic bleeds). In efficacy evaluable patients, excellent/good hemostasis 12 hours postandexanet occurred in 77 out of 98 (78.6%) and in 58 out of 70 (82.9%) patients with spontaneous and traumatic bleeding, respectively. In the subanalysis by FXa inhibitor treatment group in the efficacy population, median of percent change in anti-FXa from baseline to nadir showed a decrease of 93.8% for apixaban-treated patients (n=99) and by 92.6% for rivaroxaban-treated patients (n=59). Within 30 days, death occurred in 34 out of 227 (15.0%) patients and thrombotic events occurred in 21 out of 227 (9.3%) patients (safety population)., Conclusions: Andexanet reduced anti-FXa activity in FXa inhibitor-treated patients with ICrH, with a high rate of hemostatic efficacy. Andexanet may substantially benefit patients with ICrH, the most serious complication of anticoagulation., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02329327.

Aim: We describe the real-world utilization and outcomes associated with managing oral factor Xa inhibitor (FXai)-related major bleeds. Materials & methods: Electronic records from 45 US hospitals were queried (ICD-10-CM billing codes D68.32, T45.515x or T45.525x) to identify major bleed hospitalizations related to FXai use. Patient demographics, bleed type (intracranial hemorrhage, gastrointestinal, critical compartment, traumatic, other), FXai taken, reversal or replacement agents administered (including andexanet alfa, four-factor prothrombin complex concentrate, fresh frozen plasma, others), in-hospital mortality and length of stay were recorded. Results: Of 3030 FXai-related hospitalizations for major bleeds, patients averaged 68 years old and 47% were women. In-hospital mortality was highest for intracranial hemorrhage (23%, n = 507) and lowest for gastrointestinal bleeds (4%, n = 1453). In-hospital mortality was lowest (4%) for bleeds managed with andexanet alfa (n = 342), compared with 10% for four-factor prothrombin complex concentrate (n = 733), 11% for fresh frozen plasma (n = 925) and 8% for both other agents (n = 794) and no agents (n = 438). Median length of stay was 5 days across all agents, while ICU length of stay was shorter andexanet alfa (2 days) compared with other agents (3 days). Conclusion: In-hospital mortality differed by bleed type and agents administered. Andexanet alfa was associated with the lowest rate of in-hospital mortality across all bleed types.

Objective: To examine the healthcare economic burden of atrial fibrillation (AF) patients treated with factor Xa inhibitor (FXaI) anticoagulants who were hospitalized in the US with a major bleed (MB)., Methods: Adult AF patients treated with FXaIs and hospitalized with an MB were selected from MarketScan databases (1 January 2015-30 April 2018). Patients were grouped into cohorts based on type of MB: intracranial hemorrhage (ICH), gastrointestinal (GI), other types of MB. Healthcare costs in 2019 USD were evaluated for index hospitalizations and during a variable follow-up period in unadjusted and adjusted analyses., Results: Of the overall AF patient population treated with FXaIs and hospitalized with an MB ( n  = 7,577), 9.9% had ICH (mean age: 77.9 years; 58% male), 55.9% had GI (mean age: 76.8 years; 52% male), and 34.2% had other types of MB (mean age: 74.4 years; 61% male). Mean index hospitalization costs for ICH, GI, and other type of MB were $54,163, $26,901, and $36,645, respectively; from adjusted analyses, patients with ICH vs. GI spent 1.6 more days in the hospital; mean cost was $15,630 higher. Patients with other types of MB vs. GI spent 0.6 more days in the hospital; mean cost was $5,859 higher. Index hospitalization cost in addition to total all-cause healthcare costs incurred in the follow-up period were $34,522 higher per ICH patient and $11,584 higher per other type of MB patient vs. a GI MB patient., Limitations: Since this study was a retrospective observational study using a claims database analysis, a causal relationship between treatment with FXaIs and MB events cannot be established., Conclusions: Although all of the evaluated MB types were associated with high hospitalization costs, ICH was associated with the most substantial short- and long-term healthcare economic burden.

Introduction: As oral factor Xa (oFXa) inhibitor use has increased, so has publication of case series describing related bleeding managed with four-factor prothrombin complex concentrate (4F-PCC)., Objective: This review aimed to identify case series describing 4F-PCC management of oFXa inhibitor-related bleeding and appraise their methodological and reporting quality., Design: We searched Medline and EMBASE (1 January 2011 to 31 May 2020) to identify series of ≥10 patients with oFXa inhibitor-related major bleeding given off-label 4F-PCC. Case series were evaluated using a validated tool adapted for this topic. The tool addressed patient selection, bleed/outcome ascertainment, causal/temporal association and reporting., Results: We identified 14 case series. None had ≥100 patients (range=13-84), three were prospective, two detailed appropriate inclusion criteria and four noted consecutive inclusion. While 12 series provided clear/appropriate methods for diagnosis of intracranial haemorrhage (ICH); none did so for extracranial bleeds and it was not clear whether bleeding was adjudicated in any. Haemostatic effectiveness, thrombosis and mortality were together evaluated in 12 series, but only seven used validated methods to evaluate/diagnosis haemostasis in ICH, six in gastrointestinal bleeds, five in other bleeds and three in thrombosis. Independent adjudication of haemostasis (n=1) and thrombosis (n=2) was infrequent. Thirty-day follow-up for mortality and thrombosis was noted in five and seven series. Anticoagulation measurement/levels in at least some patients were conveyed in three series. Few series provided data on anticoagulant agent/dose (n=4), time from anticoagulant (n=4), time-to-reversal (n=7), baseline (n=7) or change (n=0) in neurologic function., Conclusions: Although many case series describe off-label use of 4F-PCC for oFXa inhibitor-related bleeding, methodological flaws and/or poor reporting necessitates caution in interpretation., Competing Interests: Competing interests: OSC, YR-M and MW have no competing interest to disclose. BL and KM-P are employees of Portola Pharmaceuticals. WB has received consultancy fees from Bayer. CIC has received grant funding and consultancy fees from Janssen Scientific Affairs and Bayer., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Heparan sulfate (HS) and heparin are sulfated polysaccharides exhibiting diverse physiological functions. HS 6-O-sulfotransferase (6-OST) is a HS biosynthetic enzyme that transfers a sulfo group to the 6-OH position of glucosamine to synthesize HS with desired biological activities. Chemoenzymatic synthesis is a widely adopted method to obtain HS oligosaccharides to support biological studies. However, this method is unable to synthesize all possible structures due to the specificity of natural enzymes. Here, we report the use of an engineered 6-OST to achieve fine control of the 6-O-sulfation. Unlike wild type enzyme, the engineered 6-OST only sulfates the non-reducing end glucosamine residue. Utilizing the engineered enzyme and wild type enzyme, we successfully completed the synthesis of five hexasaccharides and one octasaccharide differing in 6-O-sulfation patterns. We also identified a hexasaccharide construct as a new anticoagulant drug candidate. Our results demonstrate the feasibility of using an engineered HS biosynthetic enzyme to prepare HS-based therapeutics.

Introduction  A paucity of contemporary data examining bleeding-related hospitalization outcomes in atrial fibrillation (AF) patients exists. Methods  Adults in the Nationwide Readmissions Database (January 2016-November 2016) with AF and hospitalized for intracranial hemorrhage (ICH), gastrointestinal, genitourinary, or other bleeding were identified. Association between bleed types and outcomes were assessed using multivariable regression (gastrointestinal defined as referent) and reported as crude incidences and adjusted odds ratios (ORs) or mean differences with 95% confidence intervals (CIs). Results  In total, 196,878 index bleeding-related hospitalizations were identified in this AF cohort (CHA2DS2VASc score ≥2 in 95.1%), with 70.8% classified as gastrointestinal. The overall incidences of in-hospital mortality, need for post-discharge out-of-home care, and 30-day readmission were 4.9, 50.8, and 18.2%, respectively. Multivariable regression suggested traumatic and nontraumatic ICHs were associated with higher odds of in-hospital mortality (OR = 3.99, 95% CI = 3.79, 4.19; OR = 13.09, 95% CI = 12.24, 13.99) and need for post-discharge out-of-home care (OR = 2.92, 95% CI = 2.83, 3.01; OR = 2.74, 95% CI = 2.59, 2.90), and increases in mean index hospitalization length-of-stay (8.31 days, 95% CI = 8.03, 8.60, 6.27 days, 95% CI = 5.97, 6.57) versus gastrointestinal bleeding. Genitourinary and other bleeds were associated with lower mortality (OR = 0.37, 95% CI = 0.25, 0.55; OR = 0.59, 95% CI = 0.53, 0.64) and reduced length-of-stays (-2.84 days, 95% CI =  - 2.91, -2.76; -2.06 days, 95% CI =  - 2.11, -2.01) versus gastrointestinal bleeding. Genitourinary bleeds were also associated with a reduced need for post-discharge out-of-home care (OR = 0.86, 95% CI = 0.77, 0.97). Conclusion  The burden of bleeding-related hospitalizations was notably driven by relatively rare but severe and life-threatening ICH, and less morbid but more frequent gastrointestinal bleeding. There is need for continued research on bleeding risk factors and mitigation techniques to avoid bleeding-related patient hospitalizations., Competing Interests: Conflict of Interest C.I.C. has received research funding and honoraria from Portola Pharmaceuticals, Inc., Bayer AG, and Janssen Scientific Affairs LLC. M.J.A. reports consultancy or speaker fees and honoraria from Genentech, Janssen Pharmaceuticals, Boehringer Ingelheim (modest), Pfizer, Bristol-Myers Squibb, Medscape, Portola, and patents/royalties from Duke University. B.L., A.B., and K.M.P. are employees of Portola Pharmaceuticals. W.F.P. has received grants and consulting fees from Abbott, Alere, Banyan, Cardiorentis, Janssen, Portola, Pfizer, Roche, and ZS Pharma; Beckman, Boehringer-Ingelheim, Instrument Labs, Phillips, Prevencio, Singulex and The Medicine's Company, and also has ownership interests at the Comprehensive Research Associate LLC, Emergencies in Medicine LLC. B.M., M.M., O.S.C., and C.M.W. declare they have no conflict of interest., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. ( https://creativecommons.org/licenses/by/4.0/ ).)

Introduction: Direct-acting oral anticoagulants (DOACs) are associated with risk of major bleeding. This study evaluated the incremental healthcare economic burden of patients with atrial fibrillation (AF) treated with DOACs and hospitalized with a major bleed (MB)., Methods: Adult patients with AF treated with DOACs and hospitalized with MB or no MB hospitalizations during January 1, 2015-April 30, 2018 were extracted from MarketScan claims databases. The index date was defined as the first MB hospitalization for patients with MB and a random date during DOAC usage for patients without MB. Healthcare resource utilization and costs were evaluated for index hospitalizations of patients with MB and during the 6-month period prior to index dates and a variable follow-up period of 1-12 months for both patients with and those without MB. Multivariable regression analyses were performed to evaluate the incremental burden of MB vs. non-MB status on all-cause hospital days and healthcare costs., Results: Of the overall AF patient population using DOACs (N = 152,305), 7577 (5.0%) had a hospitalization for MB. Greater proportions of those who had an MB hospitalization were older and female compared to patients without MB (mean age 76.1 vs. 70.1 years; 44.1% vs. 40.5% female, respectively). For index MB hospitalizations, mean length of stay (LOS) was 5.3 days and cost was $32,938. In adjusted analyses, patients with MB had 3.6 more hospital days, $10,609 higher inpatient cost, $9613 higher outpatient medical cost, and $18,910 higher total healthcare costs for all causes per patient during follow-up (all p < 0.001). Including index MB hospitalization costs in the follow-up, all-cause total adjusted healthcare costs were almost two times higher for patients with vs. without MB ($96,590 vs. $49,091, p < 0.001)., Conclusions: Among a large US nationally representative sample of patients with AF treated with DOACs, the cost of MB hospitalization was substantial. Furthermore, healthcare costs following MB events were nearly 40% higher compared to those of patients with AF without an MB.

Background: Andexanet alfa (andexanet) is a modified human factor Xa (FXa) approved for anticoagulation reversal in patients with life-threatening bleeding treated with rivaroxaban or apixaban. Four-factor prothrombin complex concentrates (4F-PCCs) are approved for reversal of vitamin K antagonist-induced anticoagulation but not FXa inhibitors. The mechanism and effectiveness of 4F-PCCs for FXa inhibitor reversal are unclear., Objective: To investigate the mechanism and impact of 4F-PCCs on reversal of rivaroxaban and apixaban in vitro compared to andexanet., Methods: The effect of 4F-PCCs (or individual factors) on tissue factor-initiated thrombin generation (TF-TG) was evaluated in human plasma, with or without rivaroxaban or apixaban, and compared with andexanet under the same conditions., Results: In the TF-TG assay, 4F-PCC completely reversed warfarin anticoagulation. Andexanet normalized TF-TG over a wide range of apixaban and rivaroxaban concentrations tested (19-2000 ng/mL). However, 4F-PCC (or individual factors) was unable to normalize endogenous thrombin potential (ETP) or peak thrombin (Peak) in the presence of apixaban or rivaroxaban (75-500 ng/mL). TF-TG was only normalized by 4F-PCC at inhibitor concentrations <75 ng/mL (ETP) or <37.5 ng/mL (Peak). These data can be explained by the estimated thresholds of FXa activity required to support normal TF-TG based on the inhibitor:FXa ratios and levels of uninhibited FXa. The data are consistent with healthy volunteer studies where TF-TG is not normalized until inhibitor levels are substantially decreased., Conclusions: Both the theoretical calculations and experimental data demonstrated that 4F-PCCs are only able to normalize TG over a low and narrow range of FXa inhibitor concentrations (<75 ng/mL)., (© 2020 The Authors. Research and Practice in Thrombosis and Haemostasis published by Wiley Periodicals LLC on behalf of International Society on Thrombosis and Haemostasis.)

Objectives: Venous thromboembolism (VTE) incurs substantial costs to the UK National Health Service (NHS). Betrixaban is approved in the US for VTE prophylaxis with a recommended 35-42 days of treatment. This analysis modeled the budget impact of introducing betrixaban for extended-duration VTE prophylaxis in nonsurgical patients with acute medical illness at risk of VTE in the UK, where it is not yet licensed., Methods: The 5-year budget impact of introducing betrixaban into current prophylaxis (low molecular weight heparin and fondaparinux) was estimated for the UK NHS. The Phase 3 APEX study provided primary event (VTE, myocardial infarction, ischemic stroke, and death; all-cause or VTE-related) and treatment complications data. Literature informed risk of recurrent events and long-term complications, population, market share, and costs for treatment and management of events. Network meta-analyses informed symptomatic DVT, pulmonary embolism and VTE-related death rates in fondaparinux patients. Deterministic sensitivity analyses explored uncertainty., Results: Introducing betrixaban accrued savings of £1,290,000-£23,000,000 in years 1-5. Savings were from reduced primary VTE events, which reduced recurrent events and future complications. All sensitivity analyses showed savings., Conclusion: Introducing extended-duration VTE prophylaxis with betrixaban in the UK would accrue substantial savings annually over the next 5 years compared to current prophylaxis. Clinical trial registration: www.clinicaltrials.gov identifier is NCT01583218.

As with any anticoagulant, factor Xa (FXa) inhibitors are associated with a risk of major bleeding. Andexanet alfa is a recombinant modified human FXa lacking enzymatic activity, developed for reversal of FXa inhibitor-induced anticoagulation. In two phase 2, randomized, double-blind, placebo-controlled, single-center studies, different regimens of andexanet alfa were administered to healthy volunteers after therapeutic anticoagulation with rivaroxaban or edoxaban, and multiple anticoagulation reversal and safety end points were evaluated. Andexanet alfa rapidly and effectively reversed anticoagulation with both rivaroxaban and edoxaban. Within 2 minutes after bolus, anti-FXa activity decreased significantly, with maximum decreases of ≈93% (P < .05) and ≈82% (P < .05), respectively, compared with placebo. The stoichiometric ratios of andexanet alfa:total anticoagulant at maximum reversal of anti-FXa activity ranged from 1:1 to 1.3:1 for rivaroxaban and 1.41:1 to 2.58:1 for edoxaban. Sustained normalization of thrombin generation for ≈2 hours and sustained decrease in unbound anticoagulant (maximum ≈80%) for up to ≈4 hours following completion of andexanet alfa administration, compared with placebo, were observed when andexanet was administered as a bolus or as a bolus followed by continuous infusion. Andexanet alfa was well tolerated, and there were no serious adverse events or thrombotic events. Andexanet alfa has been approved in the United States and Europe for reversal of anticoagulation in patients treated with rivaroxaban or apixaban who experience life-threatening or uncontrolled bleeding. These studies were registered with clinicaltrials.gov (#NCT03578146 and #NCT03551743)., (© 2020 by The American Society of Hematology.)

Objectives: This study evaluated the frequency of hospital readmissions for venous thromboembolism (VTE) and the associated costs and length of stay (LOS) among acute medically ill patients in the US using a real-world claims database analysis. Methods: Patients (≥40 years of age) at risk of VTE due to hospitalization for acute medical illnesses, based on primary hospital discharge diagnosis codes, were identified from the MarketScan databases between July 1, 2011 and March 31, 2015. Patients were required to have continuous insurance enrollment in the 6 months prior to initial (index) hospitalizations (baseline period) and in the 6 months after hospital discharge (follow-up period). The proportions of patients with VTE-related (diagnosis at any position) and VTE as primary diagnosis hospital readmissions during the follow-up period were evaluated. The associated costs and LOS for such readmissions were also determined, as well as time to VTE-related readmissions. Results: Of the study population ( n  = 12,785; mean age = 68.3 years), most were hospitalized primarily for infectious diseases (35.2%), followed by respiratory diseases (27.9%), cancer (15.7%), heart failure (11.8%), ischemic stroke (8.1%), and rheumatic diseases (1.4%). Of the overall study population, 2.1% ( n  = 268) had a VTE-related hospital readmission in the 6 months following discharge of their index hospitalization, of which 36.6% ( n  = 98) were for a primary diagnosis of VTE. Approximately 25.4% of the VTE-related hospital readmissions occurred within the first 30 days of discharge and 58.2% within 90 days. The mean cost for a hospital readmission with a primary diagnosis of VTE was $18,681 (mean LOS = 5.0 days); for readmissions with a primary diagnosis of DVT and PE, mean costs were $14,719 and $23,305, respectively. Conclusions: Among this study population of patients hospitalized for acute medical illnesses, some experienced a VTE event requiring re-hospitalization, with 25% occurring within the first 30 days after hospital discharge.

Aims: To determine the clinical effectiveness and safety of venous thromboembolism (VTE) prophylaxis using US- and Europe-approved anticoagulants relative to extended-duration VTE prophylaxis with betrixaban. Low molecular weight heparins (LMWHs), unfractionated heparin (UFH), fondaparinux sodium and placebo were each compared to betrixaban, as standard-duration VTE prophylaxis for hospitalized, non-surgical patients with acute medical illness at risk of VTE. Materials and methods: A systematic literature review was conducted up to June 2019 to identify randomized controlled trials (RCTs) of VTE prophylaxis in hospitalized, non-surgical patients with acute medical illness at risk of VTE. Studies that reported the occurrence of VTE events (including death) and, where possible, major bleeding, from treatment initiation to 20-50 days thereafter were retrieved and extracted. A Bayesian fixed effect network meta-analysis was used to estimate efficacy and safety of betrixaban compared with standard-duration VTE prophylaxis. Results: Seven RCTs were analyzed which compared betrixaban, LMWHs, UFH, fondaparinux sodium, or placebo. There were significantly higher odds (median odds [95% credible interval]) of VTE with LMWHs (1.38 [1.12-1.70]), UFH (1.60 [1.05-2.46]), and placebo (2.37 [1.55-3.66]) compared with betrixaban. There were significantly higher odds of VTE-related death with placebo (7.76 [2.14-34.40]) compared with betrixaban. No significant differences were observed for the odds of major bleeding with all comparators, VTE-related death with any active standard-duration VTE prophylaxis, or of VTE with fondaparinux sodium, compared with betrixaban. Limitations and conclusions: In this indirect comparison, betrixaban was shown to be an effective regimen with relative benefits compared with LMWHs and UFH. This indicates that betrixaban could reduce the burden of VTE in at-risk hospitalized patients with acute medical illness who need extended prophylaxis, though without direct comparative evidence, stronger conclusions cannot be drawn.

Background: Andexanet alfa (andexanet) reverses the anticoagulant effects of factor Xa inhibitors, but it has not been assessed in clinical studies for apixaban reversal in trauma. This study evaluated andexanet for reversing apixaban anticoagulation in a porcine polytrauma model., Methods: Oral apixaban (20 mg q.d., n=21) or placebo (n=7; sham group) was administered to male pigs for 4 days before blunt liver injury and bi-lateral femur fracture. After trauma, animals were randomised 1:1:1 to a single andexanet bolus (1000 mg), a bolus (1000 mg) plus infusion (1200 mg over 2 h), or vehicle (control). Haemodynamic and coagulation variables were monitored for 5 h or until death. The primary endpoint was blood loss., Results: Mean blood loss in sham animals was 472 (standard deviation, 58) ml 12 min after injury and 658 (98) ml at 300 min, with 100% survival. Anticoagulation with apixaban significantly increased blood loss 12 min after injury [888 (133) ml, P<0.01]. Controls exhibited total blood loss of 3403 (766) ml, with 100% mortality. Andexanet bolus or bolus plus infusion significantly reduced blood loss to 1264 (205) and 1202 (95) ml, respectively), and increased survival to 100%. Haemodynamic parameters and markers of shock recovered to pre-trauma levels in andexanet-treated animals., Conclusion: Andexanet effectively reversed apixaban anticoagulation and reduced blood loss induced by severe trauma. Andexanet bolus alone had a similar impact on survival and blood loss as bolus plus infusion. Therefore, a 2 h andexanet infusion after the bolus may not be necessary to restore normal haemostatic mechanisms., (Copyright © 2019 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Botulinum neurotoxins (BoNT) are potential biothreat agents due to their high lethality, potency, and ease of distribution, thus the development of antitoxins is a high priority to the US government. This study examined pre-clinical pharmacokinetic studies in rats of four oligoclonal anti-BoNT mAb-based therapeutics (NTM-1631, NTM-1632, NTM-1633, NTM-1634) for five BoNT serotypes (A, B, E, C, and D). NTM-1631, NTM-1632, and NTM-1633 each consist of three IgG1 mAbs, each with a distinct human or humanized variable region which bind to distinct epitopes on BoNT serotype A, B, or E respectively. NTM-1634 consists of four human immunoglobulin G1 (IgG1) mAbs binding BoNT C/D mosaic toxins. The mechanism of these antitoxins requires that three antibodies simultaneously bind toxin to achieve rapid clearance. Rats (total 378) displayed no adverse clinical signs attributed to antibody treatment from any of the antitoxins. Pharmacokinetic evaluation demonstrated that the individual mAbs are slowly eliminated, exhibiting dose-dependent exposure and long elimination half-lives ranging from 6.5 days to 10 days. There were no consistent differences observed between males and females or among the individual antibodies in each formulation in half-life. Anti-drug antibodies (ADA) were observed, as expected for human antibodies administered to rats. The results presented were used to support the clinical investigation of antibody-based botulism antitoxins.

Background: Studies show that the risk of venous thromboembolism (VTE) continues post-discharge in nonsurgical patients with acute medical illness. Betrixaban is the first anticoagulant approved in the United States (US) for VTE prophylaxis extending beyond hospitalization., Objective: The aim was to establish whether betrixaban for VTE prophylaxis in nonsurgical patients with acute medical illness at risk of VTE in the US is cost-effective compared with enoxaparin., Methods: A cost-effectiveness analysis was conducted, estimating the cost per quality-adjusted life-year (QALY) gained with betrixaban (35-42 days) compared with enoxaparin (6-14 days) from a US payer perspective over a lifetime horizon. A decision tree (DT) estimated primary VTE events, thrombotic events, and treatment complications in the first 3 months based on data from the phase III Acute Medically Ill VTE Prevention with Extended Duration Betrixaban study. A Markov model estimated recurrent events and long-term complication risks from published literature. EuroQoL-5 Dimensions utility data and costs inflated to 2017 US dollars (US$) were from published literature. Results were discounted at 3.0% per annum. Deterministic and probabilistic sensitivity analyses explored uncertainty., Results: Betrixaban dominated enoxaparin, with savings of US$784 and increased QALYs of 0.017 per patient. In addition, betrixaban dominated enoxaparin across all sensitivity analyses, but was most sensitive to utilities and DT probabilities. Furthermore, probabilistic sensitivity analysis found that betrixaban was more cost-effective than enoxaparin at all willingness-to-pay thresholds., Conclusion: Betrixaban can be considered cost-effective for nonsurgical patients with acute medical illness at risk of VTE, requiring longer VTE prophylaxis from hospitalization through post-discharge.

Background: Andexanet alfa is a modified recombinant inactive form of human factor Xa developed for reversal of factor Xa inhibitors., Methods: We evaluated 352 patients who had acute major bleeding within 18 hours after administration of a factor Xa inhibitor. The patients received a bolus of andexanet, followed by a 2-hour infusion. The coprimary outcomes were the percent change in anti-factor Xa activity after andexanet treatment and the percentage of patients with excellent or good hemostatic efficacy at 12 hours after the end of the infusion, with hemostatic efficacy adjudicated on the basis of prespecified criteria. Efficacy was assessed in the subgroup of patients with confirmed major bleeding and baseline anti-factor Xa activity of at least 75 ng per milliliter (or ≥0.25 IU per milliliter for those receiving enoxaparin)., Results: Patients had a mean age of 77 years, and most had substantial cardiovascular disease. Bleeding was predominantly intracranial (in 227 patients [64%]) or gastrointestinal (in 90 patients [26%]). In patients who had received apixaban, the median anti-factor Xa activity decreased from 149.7 ng per milliliter at baseline to 11.1 ng per milliliter after the andexanet bolus (92% reduction; 95% confidence interval [CI], 91 to 93); in patients who had received rivaroxaban, the median value decreased from 211.8 ng per milliliter to 14.2 ng per milliliter (92% reduction; 95% CI, 88 to 94). Excellent or good hemostasis occurred in 204 of 249 patients (82%) who could be evaluated. Within 30 days, death occurred in 49 patients (14%) and a thrombotic event in 34 (10%). Reduction in anti-factor Xa activity was not predictive of hemostatic efficacy overall but was modestly predictive in patients with intracranial hemorrhage., Conclusions: In patients with acute major bleeding associated with the use of a factor Xa inhibitor, treatment with andexanet markedly reduced anti-factor Xa activity, and 82% of patients had excellent or good hemostatic efficacy at 12 hours, as adjudicated according to prespecified criteria. (Funded by Portola Pharmaceuticals; ANNEXA-4 ClinicalTrials.gov number, NCT02329327.)., (Copyright © 2019 Massachusetts Medical Society.)

Objectives: To assess two professional tooth bleaching products: Philips Zoom WhiteSpeed (PZW) and Ultradent Opalescence Boost PF (UOB); and to assess bleaching maintenance after use of Philips Sonicare power toothbrush (SDC) or manual toothbrush (MTB)., Methods: There was a randomized, parallel clinical trial. Eligible subjects were 18-75 years, with VITA Classical shade (VCS) of A3 on anterior teeth. Subjects were randomized to bleaching with PZW or UOB. Tooth color and shade were assessed using VITA EasyShade (VES), VCS, and VITA Bleachedguide (VBG). Subjects returned on Days 7 and 30. On Day 30, participants were dispensed either SDC or MTB for home use until Day 90., Results: A total of 135 subjects completed the study. For the primary endpoint, ΔE at Day 7, a significantly larger reduction was observed for PZW than UOB (P value = .0059). Significant differences in shade were also observed at Day 7 for VCS (P value = 0.0106), and VBG (P value = .0489). On Day 90, the SDC was statistically superior to MTB in maintaining shade per VBG and VCS, but not ΔE., Conclusions: At Day 7, PZW showed statistically greater change in overall color and shade than UOB. The SDC maintained tooth shade significantly better than MTB. Both bleaching regimens were safe., Clinical Significance: The outcomes confirm the bleaching efficacy advantage of a lower H 2 O 2 dose-LED accelerated professional tooth bleaching system, compared to a higher-dose H 2 O 2 approach. The safety assessments via clinical intraoral exam and daily logged use of subjects' desensitizing agents, and the incidence and severity of reported sensitivity, provide evidence that both professional products are safe for use. Finally, powered tooth brushing may confer an advantage to manual tooth brushing in maintaining tooth shade-change results following professional whitening., (© 2018 Wiley Periodicals, Inc.)

Purpose: Preclinical studies suggest SYK and JAK contribute to tumor-intrinsic and microenvironment-derived survival signals. The pharmacodynamics of cerdulatinib, a dual SYK/JAK inhibitor, and associations with tumor response were investigated., Patients and Methods: In a phase I dose-escalation study in adults with relapsed/refractory B-cell malignancies, cerdulatinib was administered orally to sequential dose-escalation cohorts using once-daily or twice-daily schedules. The study enrolled 8 patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), 13 with follicular lymphoma, 16 with diffuse large B-cell lymphoma (DLBCL), and 6 with mantle cell lymphoma. Correlation of tumor response with pharmacodynamic markers was determined in patients with meaningful clinical responses., Results: Following cerdulatinib administration, complete SYK and JAK pathway inhibition was achieved in whole blood of patients at tolerated exposures. Target inhibition correlated with serum cerdulatinib concentration, and IC 50 values against B-cell antigen receptor (BCR), IL2, IL4, and IL6 signaling pathways were 0.27 to 1.11 μmol/L, depending on the phosphorylation event. Significant correlations were observed between SYK and JAK pathway inhibition and tumor response. Serum inflammation markers were reduced by cerdulatinib, and several significantly correlated with tumor response. Diminished expression of CD69 and CD86 (B-cell activation markers), CD5 (negative regulator of BCR signaling), and enhanced expression of CXCR4 were observed in 2 patients with CLL, consistent with BCR and IL4 suppression and loss of proliferative capacity., Conclusions: Cerdulatinib potently and selectively inhibited SYK/JAK signaling at tolerated exposures in patients with relapsed/refractory B-cell malignancies. The extent of target inhibition in whole-blood assays and suppression of inflammation correlated with tumor response. (ClinicalTrials.gov ID:NCT01994382)., (©2018 American Association for Cancer Research.)

Background: We evaluated whether the duration of hospital stay influences venous thromboembolism (VTE) prophylaxis patterns and VTE risk during hospitalization and post-discharge among patients hospitalized for acute illnesses in the USA., Methods: Patients hospitalized for acute illnesses were identified from the US MarketScan Commercial and Medicare databases (January 1, 2012-June 30, 2015). Patients were stratified by index hospital length of stay (LOS), with study groups with 1-3 day, 4-6 day, and ≥7 day LOSs. Use of VTE prophylaxis and VTE event rates during and after hospitalization (6-month follow-up) were evaluated., Results: Of the overall population, 8647 had a 1-3 day LOS, 5551 had a 4-6 day LOS, and 3697 had a ≥7 day LOS. A greater proportion of patients with a 1-3 day LOS (66.2%) did not receive any VTE prophylaxis in comparison to patients with a 4-6 day LOS (55.0%) and ≥7 day LOS (48.8%; p <0.001). Proportions of patients with VTE events during the index hospitalization increased with longer hospital LOS (1-3 day LOS: 0.5%; 4-6 day LOS: 1.3%; ≥7 day LOS: 5.4%), as did proportions of patients with VTE events during the 6-month follow-up (1-3 day LOS: 2.4%; 4-6 day LOS: 2.7%; ≥7 day LOS: 4.2%)., Conclusion: Among this study population of hospitalized acutely ill patients in the USA, VTE pharmacologic prophylaxis was underutilized, regardless of the duration of hospital stay. However, the risk for VTE events was substantial, with nearly 10% of those with a ≥7 day LOS having suffered a VTE event within 6 months., Competing Interests: Disclosure and potential conflicts of interest: Alpesh Amin is a research consultant and/or speaker for Novosys Health, Portola, BI, BMS, and Pfizer. Alpesh Amin did not receive funding for manuscript development. W Richey Neuman was an employee of Portola Pharmaceuticals at the time of this study. Melissa Lingohr-Smith, Brandy Menges, and Jay Lin are employees of Novosys Health. The International Committee of Medical Journal Editors (ICMJE) Potential Conflicts of Interests form for the authors are available for download at http://www.drugsincontext.com/wp-content/uploads/2019/01/dic.212568-COI.pdf

The objectives of this study were to examine venous thromboembolism (VTE) prophylaxis patterns and risk for VTE events during hospitalization and in the outpatient continuum of care among patients hospitalized for acute illnesses in the United States with stratification by different age groups and renal disease status. Acutely ill hospitalized patients were identified from the MarketScan databases (January 1, 2012-June 30, 2015) and grouped by age (<65, 65-74, ≥75 years old) and whether or not they had a baseline diagnosis of renal disease, separately. Of acutely ill hospitalized patients, 60.1% (n = 10 748) were <65 years old, 15.7% (n = 2803) were 65 to 74 years old, and 24.3% (n = 4344) were ≥75 years old; 32.9% (n = 5892) had baseline renal disease. Among the study cohorts, the majority of patients received no VTE prophylaxis regardless of age or baseline renal status (52.1%-63.6%). Rates of VTE during hospitalization and in the 6 months postdischarge were 4.7%, 4.6%, and 4.5% for patients <65, 65 to 74, and ≥75 years old, respectively, and 6.3% and 3.8% for patients with and without baseline renal disease. The risk for VTE was elevated for 30 to 40 days after index admission regardless of age and renal disease status.

Introduction: Venous thromboembolism (VTE) is a leading cause of preventable morbidity and mortality among hospitalized patients in the US. The objectives of this study were to examine VTE prophylaxis patterns and risk for VTE events during hospitalization and post-discharge among patients hospitalized for acute illnesses in the US., Methods: Acutely ill hospitalized patients were identified from the MarketScan databases (January 1, 2012-June 30, 2015). Proportions of patients that received inpatient and/or outpatient VTE prophylaxis were determined. VTE rates were calculated for the overall study population and for each subpopulation with each acute illness type. Risk for VTE events after the index admission was determined by Kaplan-Meier analysis., Results: Of the acutely ill patients (n = 17,895, mean age: 58.4 years), most were hospitalized for infectious diseases (40.6%), followed by respiratory diseases (31.0%), cancer (10.7%), heart failure (10.4%), ischemic stroke (6.4%), and rheumatic diseases (0.9%). Among the entire study population, 59.1% did not receive any VTE prophylaxis, and only 7.1% received both inpatient and outpatient prophylaxis. Among the overall study population, cumulative VTE rate, including during index admission and within 6 months post-discharge, was 4.6%. VTE risk in the inpatient and outpatient continuum of care remained elevated up to 30-40 days after hospital admission, with 60.1% of VTEs occurring within 40 days of hospital admission., Conclusion: In this retrospective analysis of nearly 18,000 patients hospitalized for acute illnesses, 59.1% did not receive any VTE prophylaxis and only 7.1% received VTE prophylaxis in both the inpatient and outpatient continuum of care, despite significant VTE risk extending from hospitalization into the post-discharge period., Funding: Portola Pharmaceuticals.

Anticoagulants such as unfractionated heparin (UFH), low-molecular-weight heparins (LMWHs), fondaparinux, and direct oral anticoagulants (DOACs) targeting thrombin (IIa) or factor Xa (FXa) are widely used in prevention and treatment of thromboembolic disorders. However, anticoagulant-associated bleeding is a concern that demands monitoring and neutralization. Protamine, the UFH antidote, has limitations, while there is no antidote available for certain direct FXa inhibitors. Improved antidotes in development include UHRA (Universal Heparin Reversal Agent) for all heparin anticoagulants; andexanet alfa (andexanet), a recombinant antidote for both direct FXa inhibitors and LMWHs; and ciraparantag (PER977), a small-molecule antidote for UFH, LMWHs, and certain DOACs. The binding affinities of these antidotes for their presumed anticoagulant targets have not been compared. Here, isothermal titration calorimetry (ITC) was used to determine the affinity of each antidote for its putative targets. Clotting and chromogenic FXa assays were used to characterize neutralization activity, and electron microscopy was used to visualize the effect of each antidote on clot morphology in the absence or presence of anticoagulant. ITC confirmed binding of UHRA to all heparins, and binding of andexanet to edoxaban and rivaroxaban, and to the antithrombin-enoxaparin complex. PER977 was found to bind heparins weakly, but not the direct FXa inhibitors studied. For UHRA and andexanet, an affinity at or below the micromolar level was found to correlate with neutralization activity, while no reversal activity was observed for the PER977/anticoagulant systems. Standard metrics of clot structure were found to correlate weakly with PER977's activity. This is the first study comparing 3 antidotes in development, with each exerting activity through a distinct mechanism., (© 2018 by The American Society of Hematology.)

Introduction: Increasing use of factor Xa (FXa) inhibitors necessitates effective reversal agents to manage bleeding. Andexanet alfa, a novel modified recombinant human FXa, rapidly reverses the anticoagulation effects of direct and indirect FXa inhibitors., Objective: To evaluate the ability of andexanet to reverse anticoagulation in vitro and reduce bleeding in rabbits administered edoxaban., Materials and Methods: In vitro studies characterized the interaction of andexanet with edoxaban and its ability to reverse edoxaban-mediated anti-FXa activity. In a rabbit model of surgically induced, acute hemorrhage, animals received edoxaban vehicle+andexanet vehicle (control), edoxaban (1 mg/kg)+andexanet vehicle, edoxaban+andexanet (75 mg, 5-minute infusion, 20 minutes after edoxaban), or edoxaban vehicle+andexanet prior to injury., Results: Andexanet bound edoxaban with high affinity similar to FXa. Andexanet rapidly and dose-dependently reversed the effects of edoxaban on FXa activity and coagulation pharmacodynamic parameters in vitro. In edoxaban-anticoagulated rabbits, andexanet reduced anti-FXa activity by 82% (from 548±87 to 100±41 ng/ml; P<0.0001), mean unbound edoxaban plasma concentration by ~80% (from 100±10 to 21±6 ng/ml; P<0.0001), and blood loss by 80% vs. vehicle (adjusted for control, 2.6 vs. 12.9 g; P = 0.003). The reduction in blood loss correlated with the decrease in anti-FXa activity (r = 0.6993, P<0.0001) and unbound edoxaban (r = 0.5951, P = 0.0035)., Conclusion: These data demonstrate that andexanet rapidly reversed the anticoagulant effects of edoxaban, suggesting it could be clinically valuable for the management of acute and surgery-related bleeding. Correlation of blood loss with anti-FXa activity supports the use of anti-FXa activity as a biomarker for assessing anticoagulation reversal in clinical trials.

Objective: To evaluate healthcare resource use and costs incurred during, as well as following hospitalization for major bleeding (MB), among atrial fibrillation (AF) patients treated with factor Xa inhibitors Methods: Patients with an AF diagnosis and MB hospitalization (index event) were identified from the MarketScan Commercial and Medicare databases (January 1, 2011-December 31, 2014). Patients were required to have ≥1 prescription for rivaroxaban or apixaban within 3 months prior to MB hospitalization. AF patients treated with Xa inhibitors, but who did not have any diagnosis of MB during the study period were identified. Hospital resource use and costs were evaluated for index MB hospitalizations. Healthcare resource use and associated costs were also evaluated for up to 12 months and compared between AF patients with and without MB., Results: Of the overall patient population with AF treated with factor Xa inhibitors (n = 92,949), 3,081 (3.3%) were identified as patients with MB and 89,868 without MB. The mean hospital length of stay and hospital cost for index MB hospitalizations were 5.3 days and $28,059, respectively. Total all-cause healthcare costs were higher during the 12 months of follow-up for AF patients with MB vs without ($63,866 vs $37,916, p < .001). After adjusting for differences in patient characteristics, mean total healthcare costs were estimated at $58,169 for patients with MB vs $41,241 for patients without MB., Limitations: Since this was an observational study using a claims database analysis, a causal relationship between factor Xa inhibitor treatment and MB events cannot be inferred from the results of this study., Conclusion: In the real-world setting, the cost of initial hospitalizations for MB was substantial, and the incremental burden of total healthcare costs within 1 year following MB hospitalization was high. Approaches to better manage the continuum of care of AF patients with factor Xa inhibitor-associated MB may reduce the healthcare economic burden.

Background: Among patients hospitalized with acute heart failure (HF), the prognostic value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in short-term stroke prediction remains unclear., Methods: In the APEX trial, 7513 patients hospitalized for an acute medical illness were randomized to receive either extended-duration betrixaban (80 mg once daily for 35-42 days) or standard-of-care enoxaparin (40 mg once daily for 10 ± 4 days) for venous thromboprophylaxis. Baseline NT-proBNP concentrations were obtained in 3261 patients admitted for HF. Stroke events were adjudicated by an independent clinical events committee blinded to thromboprophylaxis allocation. The association of NT-proBNP level and other risk factors and biomarkers with stroke was assessed at 77 days after randomization., Results: In univariate analysis, the risk of stroke at 77 days was associated with baseline NT-proBNP (HR 3.63 [95% CI 1.47-8.99]; P = 0.005), D-dimer (HR 2.73 [95% CI 1.03-7.20]; P = 0.043), and hsCRP (HR 3.03 [95% CI 1.36-6.75]; P = 0.007). In multivariable analysis adjusting for hsCRP and thromboprophylaxis, NT-proBNP was associated with the risk of stroke (adjusted HR 3.64 [95% CI 1.35-9.83]; P = 0.011). The interaction of NT-proBNP with the treatment effect was not significant (P int  = 0.30)., Conclusions: Baseline NT-proBNP concentration was associated with short-term stroke among patients hospitalized with acute HF. Stroke risk assessment models should consider incorporation of NT-proBNP measurement.

Competing risk methods are time-to-event analyses that account for fatal and/or nonfatal events that may potentially alter or prevent a subject from experiencing the primary endpoint. Competing risk methods may provide a more accurate and less biased estimate of the incidence of an outcome but are rarely applied in cardiology trials. APEX investigated the efficacy of extended-duration betrixaban versus standard-duration enoxaparin to prevent a composite of symptomatic deep-vein thrombosis (proximal or distal), nonfatal pulmonary embolism, or venous thromboembolism (VTE)-related death in acute medically ill patients (n = 7513). The aim of the current analysis was to determine the efficacy of betrixaban vs standard-duration enoxaparin accounting for non-VTE-related deaths using the Fine and Gray method for competing risks. The proportion of non-VTE-related death was similar in both the betrixaban (133, 3.6%) and enoxaparin (136, 3.7%) arms, P = .85. Both the traditional Kaplan-Meier method and the Fine and Gray method accounting for non-VTE-related death as a competing risk showed equal reduction of VTE events when comparing betrixaban to enoxaparin (HR/SHR = 0.65, 95% 0.42-0.99, P = 0.046). Due to the similar proportion of non-VTE-related deaths in both treatment arms and the use of a univariate model, the Fine and Gray method provided identical results to the traditional Cox model. Using the Fine and Gray method in addition to the traditional Cox proportional hazards method can indicate whether the presence of a competing risk, which is dependent of the outcome, altered the risk estimate., (Copyright © 2017 John Wiley & Sons, Ltd.)

Essentials Anticoagulants prevent venous thromboembolism but may be associated with greater bleeding risks. Bivariate analysis assumes a non-linear relationship between efficacy and safety outcomes. Extended full-dose betrixaban is favorable over standard enoxaparin in bivariate endpoint. Clinicians must weigh efficacy and safety outcomes in decision-making on thromboprophylaxis., Summary: Background Among acutely ill hospitalized medical patients, extended-duration thromboprophylaxis reduces the risk of venous thromboembolism (VTE), but some pharmacologic strategies have been associated with greater risks of major bleeding, thereby offsetting the net clinical benefit (NCB). Methods To assess the risk-benefit profile of anticoagulation regimens, a previously described bivariate method that does not assume a linear risk-benefit tradeoff and can accommodate different margins for efficacy and safety was performed to simultaneously assess efficacy (symptomatic VTE) and safety (major bleeding) on the basis of data from four randomized controlled trials of extended-duration (30-46 days) versus standard-duration (6-14 days) thromboprophylaxis among 28 227 patients (EXCLAIM, ADOPT, MAGELLAN and APEX trials). Results Extended thromboprophylaxis with full-dose betrixaban (80 mg once daily) was superior in efficacy and non-inferior in safety to standard-duration enoxaparin, and showed a significantly favorable NCB, with a risk difference of - 0.51% (- 0.89% to - 0.10%) in the bivariate outcome. Extended enoxaparin was superior in efficacy and inferior in safety (bivariate outcome: 0.03% [- 0.37% to 0.43%]), whereas apixaban and rivaroxaban were non-inferior in efficacy and inferior in safety (- 0.20% [- 0.49% to 0.17%] and 0.23% [- 0.16% to 0.69%], respectively). Reduced-dose betrixaban did not show a significant difference in either efficacy or safety (0.41% [- 0.85% to 1.94%]). Conclusions In a bivariate analysis that assumes non-linear risk-benefit tradeoffs, extended prophylaxis with full-dose betrixaban was superior to standard-duration enoxaparin, whereas other regimens failed to simultaneously achieve both superiority and non-inferiority with respect to symptomatic VTE and major bleeding in the management of acutely ill hospitalized medical patients., (© 2017 International Society on Thrombosis and Haemostasis.)

Direct factor Xa (FXa) inhibitors lack a specific reversal agent for emergencies such as major bleeding or urgent surgery. Andexanet alfa, a modified, catalytically inactive, recombinant human FXa derivative, reverses anticoagulant effect by binding and sequestering FXa inhibitors. This original report of safety and dose-finding, phase 1 and 2 randomized, double-blind, placebo-controlled studies, investigated various doses of andexanet in healthy volunteers. Phase 1 evaluated the safety and pharmacokinetics of andexanet (n = 24) or placebo (n = 8). In phase 2, andexanet (n = 36) or placebo (n = 18) was administered following steady-state apixaban dosing (5 mg twice daily for 6 days); safety, pharmacokinetics, and pharmacodynamics were assessed. Andexanet plasma concentration increased proportionally with dose, with rapid elimination (terminal elimination half-life, 4.35-7.5 hours). Following apixaban treatment, andexanet rapidly (≤2 minutes) and dose dependently reduced unbound apixaban concentration vs placebo (51% to 89% vs 5% reduction; all P < .05), decreased anti-FXa activity (67.8% to 95.0% vs 7.1% reduction; all P < .05), and restored thrombin generation in 67% to 100% vs 6% of subjects (all P < .01), maintaining these effects during continuous 45- and 120-minute infusions. Andexanet was well tolerated. Nine subjects had mild/moderate infusion reactions not associated with hemodynamic changes or respiratory compromise that generally resolved without intervention or dose reduction. There were no thrombotic events or other serious safety issues. In conclusion, andexanet reversed apixaban-mediated effects on pharmacodynamic markers of anticoagulation in healthy volunteers within minutes after administration and for the duration of infusion. This trial was registered at www.clinicaltrials.gov as #NCT01758432., Competing Interests: Conflict-of-interest disclosure: G.L., J.M.L., M. Karbarz, J.C., J.T.C., and P.B.C. are current employees of Portola Pharmaceutical. V.M., A.H., U.S., M. Kitt, M.M., and S.J.H. are past employees of Portola Pharmaceuticals. D.S. has attended advisory boards for Boerhinger Ingelheim, Daiichi-Sankyo, Servier, and Portola Pharmaceuticals and has received honoraria from Bristol-Myers Squibb–Pfizer and Bayer. M.C. has attended advisory boards for Janssen, Leo Pharma, Portola Pharmaceuticals, and Asahi Kasei Pharma America and has received funding for presentations from Leo Pharma, Bayer, Celgene, Shire, and CSL Behring. M.C.’s institution has received funding for research projects from Leo Pharma.

Essentials There is currently no approved reversal agent for factor Xa (FXa) inhibitors Andexanet alfa has been developed to reverse the anticoagulant effects of FXa inhibitors Andexanet reduced blood loss and anticoagulation markers in rivaroxaban-anticoagulated rabbits Andexanet was well tolerated in monkeys and rats, with no evidence of prothrombotic activity SUMMARY: Background Andexanet alfa is a recombinant modified form of factor Xa (FXa), designed to bind to and reverse the anticoagulant activity of FXa inhibitors. Objectives To evaluate the ability of andexanet to reverse the anticoagulant activity of rivaroxaban, and assess its pharmacokinetics (PK) and toxicity in animal models. Methods The effects of andexanet on blood loss, anti-FXa activity, rivaroxaban unbound plasma concentrations and other coagulation parameters were assessed in a rabbit liver laceration 'treatment' model. Andexanet was administered 10 min after blood loss was initiated. The toxicity of repeated administration of andexanet (up to 60 mg kg -1 day -1 ) was assessed in cynomolgus monkeys. PK parameters were evaluated in rats and monkeys. Results Excess blood loss due to anticoagulation with rivaroxaban was significantly decreased by a single intravenous bolus administration of andexanet at 35 and 75 mg per rabbit, by 75% and 63%, respectively. This correlated with dose-dependent decreases in the unbound fraction of rivaroxaban and anti-FXa activity. Co-administration of rivaroxaban had no significant impact on the PK parameters of andexanet. Andexanet (up to 60 mg kg -1 day -1 ) was well tolerated in monkeys, with no accumulation of andexanet or rivaroxaban. There was a single occurrence of anaphylaxis, which resolved after treatment with diphenhydramine and epinephrine. There was no histological evidence of prothrombotic activity with high-dose andexanet compared with vehicle control, as measured by clot and fibrin deposition in all major organs. Conclusions These data suggest that andexanet is a promising therapy for the reversal of FXa inhibitor-induced anticoagulation, supporting clinical studies in humans., (© 2017 International Society on Thrombosis and Haemostasis.)

Background: Extended-duration betrixaban showed a significant reduction in venous thromboembolism in the APEX trial (Acute Medically Ill VTE Prevention With Extended Duration Betrixaban Study). Given the variable clinical impact of different efficacy and safety events, one approach to assess net clinical outcomes is to include only those events that are either fatal or cause irreversible harm., Methods and Results: This was a post hoc analysis of the APEX trial-a multicenter, double-blind, randomized controlled trial comparing extended-duration betrixaban versus standard-of-care enoxaparin. A composite of all fatal or irreversible safety (fatal bleeding or intracranial hemorrhage) and efficacy events (cardiopulmonary death, myocardial infarction, pulmonary embolism, and ischemic stroke) was evaluated in a time-to-first event analysis. In patients with positive D-dimer results, betrixaban reduced fatal or irreversible events at 35 to 42 days (4.80% versus 3.54%; hazard ratio, 0.73; absolute risk reduction, 1.26%; number needed to treat, 79 [ P =0.033]) and at study end at 77 days (6.27% versus 4.36%; hazard ratio, 0.70; absolute risk reduction, 1.91%; number needed to treat, 52 [ P =0.005]) versus enoxaparin. In all patients, betrixaban reduced fatal or irreversible events at 35 to 42 days (4.08% versus 2.90%; hazard ratio, 0.71; absolute risk reduction, 1.18%; number needed to treat, 86 [ P =0.006]) and 77 days (5.17% versus 3.64%; hazard ratio, 0.70; absolute risk reduction, 1.53%; number needed to treat, 65 [ P =0.002])., Conclusions: Among hospitalized medically ill patients, extended-duration betrixaban demonstrated an ≈30% reduction in fatal or irreversible ischemic or bleeding events compared with standard-duration enoxaparin. A total of 65 patients would require treatment with betrixaban to prevent 1 fatal or irreversible event versus enoxaparin., Clinical Trial Registration: URL: http://www.ClinicalTrials.gov. Unique identifier: NCT01583218., (© 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.)

Background  The IMPROVE score is a validated venous thromboembolism (VTE) assessment tool to risk stratify hospitalized, medically ill patients based on clinical variables. It was hypothesized that addition of D-dimer measurement to derive a new IMPROVEDD score would improve identification of at risk of VTE. Methods  The association of the IMPROVE score and D-dimer ≥ 2 × the upper limit of normal (ULN) with the risk of symptomatic deep vein thrombosis, nonfatal pulmonary embolism, or VTE-related death was evaluated in 7,441 hospitalized, medically ill patients randomized in the APEX trial. Based on the Cox regression analysis, the IMPROVEDD score was derived by adding two points to the IMPROVE score if the D-dimer was ≥ 2 × ULN. Results  Baseline D-dimer was independently associated with symptomatic VTE through 77 days (adjusted HR: 2.22 [95% CI: 1.38-1.58], p  = 0.001). Incorporation of D-dimer into the IMPROVE score improved VTE risk discrimination (ΔAUC: 0.06 [95% CI: 0.02-0.09], p  = 0.0006) and reclassification (continuous NRI: 0.34 [95% CI: 0.17-0.51], p  = 0.001; categorical NRI: 0.13 [95% CI: 0.03-0.23], p  = 0.0159). Patients with an IMPROVEDD score of ≥2 had a greater VTE risk compared with those with an IMPROVEDD score of 0 to 1 (HR: 2.73 [95% CI: 1.52-4.90], p  = 0.0007). Conclusion  Incorporation of D-dimer into the IMPROVE VTE risk assessment model further improves risk stratification in hospitalized, medically ill patients who received thromboprophylaxis. An IMPROVEDD score of ≥2 identifies hospitalized, medically ill patients with a heightened risk for VTE through 77 days.

Purpose: B-cell receptor (BCR)-associated kinase inhibitors, such as ibrutinib, have revolutionized the treatment of chronic lymphocytic leukemia (CLL). However, these agents are not curative, and resistance is already emerging in a proportion of patients. IL4, expressed in CLL lymph nodes, can augment BCR signaling and reduce the effectiveness of BCR kinase inhibitors. Therefore, simultaneous targeting of the IL4- and BCR signaling pathways by cerdulatinib, a novel dual Syk/JAK inhibitor currently in clinical trials (NCT01994382), may improve treatment responses in patients. Experimental Design: PBMCs from patients with CLL were treated in vitro with cerdulatinib alone or in combination with venetoclax. Cell death, chemokine, and cell signaling assay were performed and analyzed by flow cytometry, immunoblotting, q-PCR, and ELISA as indicated. Results: At concentrations achievable in patients, cerdulatinib inhibited BCR- and IL4-induced downstream signaling in CLL cells using multiple readouts and prevented anti-IgM- and nurse-like cell (NLC)-mediated CCL3/CCL4 production. Cerdulatinib induced apoptosis of CLL cells, in a time- and concentration-dependent manner, and particularly in IGHV-unmutated samples with greater BCR signaling capacity and response to IL4, or samples expressing higher levels of sIgM, CD49d + , or ZAP70 + Cerdulatinib overcame anti-IgM, IL4/CD40L, or NLC-mediated protection by preventing upregulation of MCL-1 and BCL-X L ; however, BCL-2 expression was unaffected. Furthermore, in samples treated with IL4/CD40L, cerdulatinib synergized with venetoclax in vitro to induce greater apoptosis than either drug alone. Conclusions: Cerdulatinib is a promising therapeutic for the treatment of CLL either alone or in combination with venetoclax, with the potential to target critical survival pathways in this currently incurable disease. Clin Cancer Res; 23(9); 2313-24. ©2016 AACR ., (©2016 American Association for Cancer Research.)

Background: The APEX trial assessed the safety and efficacy of extended-duration thromboprophylaxis using betrixaban versus standard dosing of enoxaparin among hospitalized, acutely ill medical patients. The 80-mg betrixaban dose was halved to 40 mg among subjects with severe renal insufficiency and those receiving a concomitant strong P-glycoprotein inhibitor., Methods: This analysis assessed the pharmacokinetics, efficacy, and safety of full- (80 mg) and reduced-dose (40 mg) betrixaban relative to enoxaparin in the APEX trial., Results: The median concentration of betrixaban among subjects administered the 80-mg dose was higher than that of the 40-mg dose (19 ng/mL vs 11 ng/mL, P<.001). In the primary analysis cohort 1 (d-dimer ≥2× upper limit of normal), the primary efficacy outcome (asymptomatic proximal deep vein thrombosis, symptomatic proximal or distal deep vein thrombosis, symptomatic nonfatal pulmonary embolism, or venous thromboembolism-related death) was significantly reduced among subjects treated with 80 mg of extended-duration betrixaban versus enoxaparin (6.27% [95/1516] vs 8.39% [130/1549], relative risk reduction=0.26 [0.04-0.42], P=.023), and similarly in the entire primary efficacy outcome population (4.87% [122/2506] vs 7.06% [181/2562], relative risk reduction=0.30 [0.13-0.44], P=.001). There was no difference in the primary outcome for subjects treated with 40 mg betrixaban vs enoxaparin across cohorts. In addition, there was no excess of major bleeding associated with either betrixaban dose compared with enoxaparin., Conclusions: The 80-mg betrixaban dose achieves higher plasma concentrations than the 40-mg dose and, in contrast to the 40-mg dose, is associated with improved efficacy across all cohorts relative to standard-dose enoxaparin without an excess risk of major bleeding in the management of medically ill subjects., (Copyright © 2016. Published by Elsevier Inc.)

Ibrutinib (BTK inhibitor) has generated remarkable responses in CLL. However, the drug, to a large extent, does not cause cell death directly and does not eradicate CLL malignant clones. Inability to eradicate CLL has fostered resistance generation. Once patients become resistant, they do poorly with a median survival of 3-4 months. Novel therapeutic strategies are needed to prevent resistance, improve treatment outcome and ultimately cure the disease. Herein, we explore dual targeting of the BCR and JAK-STAT pathways with a novel single agent, cerdulatinib, which selectively inhibits both SYK (a BCR component) and JAK kinases. We demonstrated that cerdulatinib delivered potent tumor inhibition in 60 primary CLL patient samples, especially in those with poor prognostic indicators. Importantly, cerdulatinib, but not ibrutinib, is able to overcome the support of microenvironment and induces CLL cell death at clinically achievable concentrations. Notably, cerdulatinib blocked proliferation of ibrutinib-resistant primary CLL cells and of BTKC481S-transfected/ibrutinib-resistant lymphoma cells. These anti-tumor effects are well correlated with the inhibition of BCR and JAK-STAT signaling and downstream inhibition of the functions of AKT, ERK and NFκB. Collectively, our results show that simultaneous targeting of BCR and JAK-STAT pathways is a more effective strategy relative to single BTK inhibition.

Background: Stroke is a morbid and potentially mortal complication among patients hospitalized with acute medical illness. The potential of extended-duration thromboprophylaxis with the factor Xa inhibitor betrixaban to reduce the risk of stroke compared with standard-dose enoxaparin in this population was assessed in this retrospective APEX trial substudy (Acute Medically Ill Venous Thromboembolism Prevention With Extended Duration Betrixaban)., Methods: Hospitalized acutely medically ill subjects (n=7513) were randomized in a double-dummy double-blind fashion to either extended-duration oral betrixaban (80 mg once daily for 35-42 days) or standard-dose subcutaneous enoxaparin (40 mg once daily for 10±4 days) for venous thromboprophylaxis. Stroke events were adjudicated by an independent, blinded event adjudication committee., Results: The mean age of study participants was 76 years; 45% were male; 13% had had a stroke; and 45% had congestive heart failure. There were fewer all-cause strokes (0.54% versus 0.97%; relative risk [RR]=0.56; 95% confidence interval, 0.32-0.96; P =0.032; adjusted RR=0.43%; number needed to treat=233) and ischemic strokes (0.48% versus 0.91%; RR=0.53; 95% confidence interval, 0.30-0.94; P =0.026; adjusted RR=0.43%; number needed to treat=233) among patients treated with betrixaban versus enoxaparin through 77 days of follow-up. Among high-risk subjects, those with congestive heart failure or ischemic stroke as their index event, betrixaban reduced the risk of all-cause stroke (0.72% versus 1.48%; RR=0.49; 95% confidence interval, 0.26-0.90; P =0.019; adjusted RR=0.76%; number needed to treat=132) and ischemic stroke (0.63% versus 1.38%; RR=0.45; 95% confidence interval, 0.24-0.87; P =0.014; adjusted RR=0.75%; number needed to treat=134) compared with enoxaparin., Conclusions: Among hospitalized medically ill patients, extended-duration betrixaban significantly reduced all-cause stroke and ischemic stroke through 77 days of follow-up CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01583218., (© 2016 American Heart Association, Inc.)

The spleen tyrosine kinase (SYK) regulates immune cell activation in response to engagement of a variety of receptors, making it an intriguing target for the treatment of inflammatory and autoimmune disorders as well as certain B-cell malignancies. We have previously reported on the discovery and preclinical characterization of PRT062607, a potent and highly selective inhibitor of SYK that exhibits robust anti-inflammatory activity in a variety of animal models. Here we present data from our first human studies aimed at characterizing the pharmacokinetics (PK), pharmacodynamics (PD), and safety of PRT062607 in healthy volunteers following single and multiple oral administrations. PRT062607 demonstrated a favorable PK profile and the ability to completely inhibit SYK activity in multiple whole-blood assays. The PD half-life in the more sensitive assays was approximately 24 hours and returned to predose levels by 72 hours. Selectivity for SYK was observed at all dose levels tested. Analysis of the PK/PD relationship indicated an IC 50 of 324 nM for inhibition of B-cell antigen receptor-mediated B-cell activation and 205 nM for inhibition of FcεRI-mediated basophil degranulation. PRT062607 was safe and well tolerated across the entire range of doses. Clinical PK/PD was related to in vivo anti-inflammatory activity of PRT062607 in the rat collagen-induced arthritis model, which predicts that therapeutic concentrations may be safely achieved in humans for the treatment of autoimmune disease. PRT062607 has a desirable PK profile and is capable of safely, potently, and selectively suppressing SYK kinase function in humans following once-daily oral dosing., (© 2016, The Authors. The Journal of Clinical Pharmacology Published by Wiley Periodicals, Inc. on behalf of American College of Clinical Pharmacology.)