Andexanet alfa or prothrombin complex concentrate for acute reversal of oral factor Xa inhibitors: monitoring of antidote effects.

This study in vitro comprehensively assessed reversal of the anticoagulant effects of rivaroxaban, an oral factor Xa inhibitor, using andexanet alfa and various prothrombin complex concentrate (PCC) products in a battery of tests. In static coagulation assays, andexanet alpha outperformed PCCs except for activated PCC being more effective in standard coagulation times. However, in a flow chamber model mimicking arterial shear, both andexanet alpha and high-concentration PCC restored fibrin formation, but not platelet adhesion. In the Russell's viper venom test and anti-Xa assay, only andexanet alpha could be tested for efficacy. The antidote effects of andexanet alpha and PCCs in restoring coagulation can be qualitatively or selectively demonstrated using in vitro coagulation tests.

Rivaroxaban attenuates neutrophil maturation in the bone marrow niche.

Pharmacological inhibition of factor Xa by rivaroxaban has been shown to mediate cardioprotection and is frequently used in patients with, e.g., atrial fibrillation. Rivaroxaban's anti-inflammatory actions are well known, but the underlying mechanisms are still incompletely understood. To date, no study has focused on the effects of rivaroxaban on the bone marrow (BM), despite growing evidence that the BM and its activation are of major importance in the development/progression of cardiovascular disease. Thus, we examined the impact of rivaroxaban on BM composition under homeostatic conditions and in response to a major cardiovascular event. Rivaroxaban treatment of mice for 7 days markedly diminished mature leukocytes in the BM. While apoptosis of BM-derived mature myeloid leukocytes was unaffected, lineage-negative BM cells exhibited a differentiation arrest at the level of granulocyte-monocyte progenitors, specifically affecting neutrophil maturation via downregulation of the transcription factors Spi1 and Csfr1. To assess whether this persists also in situations of increased leukocyte demand, mice were subjected to cardiac ischemia/reperfusion injury (I/R): 7 d pretreatment with rivaroxaban led to reduced cardiac inflammation 72 h after I/R and lowered circulating leukocyte numbers. However, BM myelopoiesis showed a rescue of the leukocyte differentiation arrest, indicating that rivaroxaban's inhibitory effects are restricted to homeostatic conditions and are mainly abolished during emergency hematopoiesis. In translation, ST-elevation MI patients treated with rivaroxaban also exhibited reduced circulating leukocyte numbers. In conclusion, we demonstrate that rivaroxaban attenuates neutrophil maturation in the BM, which may offer a therapeutic option to limit overshooting of the immune response after I/R.

Oral factor Xa inhibitor underutilization following lower extremity peripheral vascular intervention.

OBJECTIVE: Patients undergoing peripheral vascular intervention (PVI) (ie, endovascular revascularization) for symptomatic lower extremity peripheral artery disease remain at high risk for major adverse limb and cardiovascular events. High-quality evidence demonstrates the addition of a low-dose oral factor Xa inhibitor to single antiplatelet therapy, termed dual pathway inhibition (DPI), reduces the incidence of major adverse events in this population. This study aims to describe the longitudinal trends in factor Xa inhibitor initiation after PVI, identify patient and procedural characteristics associated with factor Xa inhibitor use, and describe temporal trends in antithrombic therapy post-PVI before vs after VOYAGER PAD. METHODS: This retrospective cross-sectional study was performed using data from the Vascular Quality Initiative PVI registry from January 2018 through June 2022. Multivariate logistic regression was utilized to determine predictors of factor Xa inhibitor initiation following PVI, reported as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: A total of 91,569 PVI procedures were deemed potentially eligible for factor Xa inhibitor initiation and were included in this analysis. Overall rates of factor Xa inhibitor initiation after PVI increased from 3.5% in 2018 to 9.1% in 2022 (P < .0001). The strongest positive predictors of factor Xa inhibitor initiation after PVI were non-elective (OR, 4.36; 95% CI, 4.06-4.68; P < .0001) or emergent (OR, 8.20; 95% CI, 7.14-9.41; P < .0001) status. The strongest negative predictor was postoperative dual antiplatelet therapy prescription (OR, 0.20; 95% CI, 0.17-0.23; P < .0001), highlighting significant hesitation about use of DPI after PVI and limited translation of VOYAGER PAD findings into clinical practice. Antiplatelet medications remain the most common antithrombotic regimen after PVI, with almost 70% of subjects discharged on dual antiplatelet therapy and approximately 20% discharged on single antiplatelet therapy. CONCLUSIONS: Factor Xa inhibitor initiation after PVI has increased in recent years, although the absolute rate remains low, and most eligible patients are not prescribed this treatment.

Risk of hospitalization for upper gastrointestinal bleeding in Helicobacter pylori eradicated patients newly started on warfarin or direct oral anticoagulants: A population-based cohort study.

BACKGROUND: To investigate risks of hospitalization for upper gastrointestinal bleeding (UGIB) in H. pylori-eradicated patients newly started on warfarin or direct oral anti-coagulants (DOACs). METHODS: We identified all patients who had previously received H. pylori eradication therapy or were found to have no H. pylori on endoscopy and were then newly started on warfarin or DOACs from a population-based electronic healthcare database. Primary analysis was the risk of UGIB between warfarin and DOACs users in H. pylori-eradicated patients. Secondary analysis included the UGIB risk between H. pylori-eradicated and H. pylori-negative patients who were newly started on warfarin or DOACs. The hazard ratio (HR) of UGIB was approximated by pooled logistic regression model incorporating the inverse propensity of treatment weightings with time-varying covariables. RESULTS: Among H. pylori-eradicated patients, DOACs had a significantly lower risk of UGIB (HR: 0.26, 95% CI 0.09-0.71) compared with warfarin. In particular, lower UGIB risks with DOACs were observed among older (≥65 years) patients, female, those without a history of UGIB or peptic ulcer, or ischemic heart disease, and non-users of acid-suppressive agents or aspirin. Secondary analysis showed no significant difference in UGIB risk between H. pylori-eradicated and H. pylori-negative patients newly started on warfarin (HR: 0.63,95% CI 0.33-1.19) or DOACs (HR: 1.37, 95% CI 0.45-4.22). CONCLUSIONS: In H. pylori-eradicated patients, new users of DOACs had a significantly lower risk of UGIB than new warfarin users. Furthermore, the risk of UGIB in new warfarin or DOACs users was comparable between H. pylori-eradicated and H. pylori-negative patients.

Comparisons of effectiveness and safety between on-label dosing, off-label underdosing, and off-label overdosing in Asian and non-Asian atrial fibrillation patients treated with rivaroxaban: a systematic review and meta-analysis of observational studies.

AIMS: Limited real-world data show that rivaroxaban following dosage criteria from either ROCKET AF [20 mg/day or 15 mg/day if creatinine clearance (CrCl) < 50 mL/min] or J-ROCKET AF (15 mg/day or 10 mg/day if CrCl < 50 mL/min) is associated with comparable risks of thromboembolism and bleeding with each other in patients with non-valvular atrial fibrillation (NVAF). We are aimed to study whether these observations differ between Asian and non-Asian subjects. METHODS AND RESULTS: A systematic review and meta-analysis with random effects was conducted to estimate the aggregate hazard ratio (HR) and 95% confidence interval (CI) using PubMed and MEDLINE databases from 8 September 2011 to 31 December 2022 searched for adjusted observational studies that reported relevant clinical outcomes of NVAF patients receiving rivaroxaban 10 mg/day if CrCl > 50 mL/min, on-label dose rivaroxaban eligible for ROCKET AF or J-ROCKET AF, and rivaroxaban 20 mg/day if CrCl < 50 mL/min. Effectiveness and safety endpoints were compared between ROCKET AF and J-ROCKET AF dosing regimen in Asian and non-Asian subjects, separately. Also, risks of events of rivaroxaban 10 mg/day despite of CrCl > 50 mL/min and rivaroxaban 20 mg/day despite of CrCl < 50 mL/min were compared to that of 'ROCKET AF/J-ROCKET AF dosing'. Sensitivity analyses were performed by sequential elimination of each study from the pool. The meta-regression analysis was performed to explore the influence of potential factors on the effectiveness and safety outcomes. Eighteen studies involving 67 571 Asian and 54 882 non-Asian patients were included. Rivaroxaban following J-ROCKET AF criteria was associated with comparable risks of thromboembolism in the Asian subgroup, whereas rivaroxaban following J-ROCKET AF criteria was associated with higher risks of all-cause mortality (HR:1.30; 95% CI:1.05-1.60) compared with that of ROCKET AF criteria in the non-Asian population. There were no differences in risks of major bleeding between rivaroxaban following J-ROCKET AF vs. ROCKET AF criteria either in the Asian or non-Asian population. The use of rivaroxaban 10 mg despite of CrCl > 50 mL/min was associated with a higher risk of thromboembolism (HR:1.64; 95% CI:1.28-2.11) but lower risk of major bleeding (HR:0.72; 95% CI:0.57-0.90) compared with eligible dosage criteria. The use of rivaroxaban 20 mg despite of CrCl < 50 mL/min was associated with worse clinical outcomes in the risks of thromboembolism (HR:1.32; 95% CI:1.09-1.59), mortality (HR:1.33; 95% CI:1.10-1.59), and major bleeding (HR:1.26; 95% CI:1.03-1.53) compared with eligible dosage criteria. The pooled results were generally in line with the primary effectiveness and safety outcomes by removing a single study at one time. Meta-regression analyses failed to detect the bias in most potential patient characteristics associated with the clinical outcomes. CONCLUSION: Rivaroxaban dosing regimen following J-ROCKET criteria may serve as an alternative to ROCKET AF criteria for the Asian population with NVAF, whereas the dosing regimen following ROCKET AF criteria was more favourable for the non-Asian population. The use of rivaroxaban 10 mg despite of CrCl > 50 mL/min was associated with a higher risk of thromboembolism but a lower risk of major bleeding, while use of rivaroxaban 20 mg despite of CrCl < 50 mL/min was associated with worse outcome in most clinical events.

Comparison of 4-factor prothrombin complex concentrate and andexanet alfa for reversal of apixaban and rivaroxaban in the setting of intracranial hemorrhage.

The purpose of this study was to evaluate and compare clinical outcomes in patients who experienced intracranial hemorrhage (ICH) while taking apixaban or rivaroxaban and were reversed with four-factor prothrombin complex concentrates (4F-PCC) or andexanet alfa (AA). This retrospective cohort included adult patients that received 4F-PCC or AA for the initial management of an apixaban- or rivaroxaban-associated ICH. A primary outcome of excellent or good hemostatic efficacy at 12 h post-reversal was assessed. Secondary outcomes evaluated were change in hematoma volume size at 12 h, functional status at discharge, need for surgical intervention or additional hemostatic agents post-reversal, new thrombotic event within 28 days, 28-day all-cause mortality, discharge disposition, and hospital and intensive care unit lengths of stay. A total of 70 patients were included (4F-PCC, n = 47; AA, n = 23). For the primary outcome analysis, 21 patients were included in the 4F-PCC group and 12 in the AA group. The rate of effective hemostasis was similar between the 4F-PCC and AA groups (66.7% vs 75%, p = 0.62). There were no statistically significant differences between the groups for secondary outcomes, including 28-day mortality (40.4% vs 39.1%, p = 0.92) and thrombotic complications within 28 days of reversal (17.0% vs 21.7%, p = 0.63). In patients who experienced an ICH while taking apixaban or rivaroxaban, 4F-PCC and AA were found to have similar rates of excellent or good hemostatic efficacy.

Comparison of Managing Factor Xa Inhibitor to Unfractionated Heparin Transitions by aPTT Versus a Treatment Guideline Utilizing Heparin Anti-Xa Levels.

BACKGROUND: There are inadequate data on the optimal strategy for transitioning factor Xa inhibitors (FXai; apixaban, rivaroxaban) to unfractionated heparin (UFH) infusions. OBJECTIVE: In patients transitioning from an FXai to an UFH infusion, this study compared the safety and efficacy of monitoring UFH infusions using an activated partial thromboplastin time (aPTT) titration scale versus utilizing an UFH-calibrated anti-Xa titration scale aided by a novel institutional guideline. METHODS: A retrospective cohort analysis was conducted on adult patients transitioning from an FXai to an UFH infusion at 2 medical centers from June 1, 2018, to November 1, 2020. One institution utilized aPTT while the other institution primarily used UFH-calibrated anti-Xa. The primary endpoint was a composite of death, major bleeding, or new thrombosis during the hospitalization with a planned noninferiority analysis. Secondary outcomes were also collected including the amount and duration of UFH administered between cohorts. RESULTS: The incidence rate of the primary composite endpoint was 6.3% in the anti-Xa group and 11% in the aPTT group (P < 0.001 for noninferiority, P = 0.138 for superiority) meeting noninferiority criteria. No statistical differences were seen in new thrombosis, major bleeding, or any bleeding. CONCLUSION AND RELEVANCE: This represents the first report of a comparison between aPTT versus anti-Xa monitoring in relation to clinical outcomes for patients transitioning from an FXai to an UFH infusion. A transition guideline primarily utilizing an UFH-calibrated anti-Xa assay appears to be a safe alternative to aPTT monitoring and can aid facilities in the management of patients during these complex transitions.

Andexanet alfa versus four-factor prothrombin complex concentrate for the reversal of apixaban- or rivaroxaban-associated intracranial hemorrhage: a propensity score-overlap weighted analysis.

BACKGROUND: Andexanet alfa is approved (FDA "accelerated approval"; EMA "conditional approval") as the first specific reversal agent for factor Xa (FXa) inhibitor-associated uncontrolled or life-threatening bleeding. Four-factor prothrombin complex concentrates (4F-PCC) are commonly used as an off-label, non-specific, factor replacement approach to manage FXa inhibitor-associated life-threatening bleeding. We evaluated the effectiveness and safety of andexanet alfa versus 4F-PCC for management of apixaban- or rivaroxaban-associated intracranial hemorrhage (ICH). METHODS: This two-cohort comparison study included andexanet alfa patients enrolled at US hospitals from 4/2015 to 3/2020 in the prospective, single-arm ANNEXA-4 study and a synthetic control arm of 4F-PCC patients admitted within a US healthcare system from 12/2016 to 8/2020. Adults with radiographically confirmed ICH who took their last dose of apixaban or rivaroxaban < 24 h prior to the bleed were included. Patients with a Glasgow Coma Scale (GCS) score < 7, hematoma volume > 60 mL, or planned surgery within 12 h were excluded. Outcomes were hemostatic effectiveness from index to repeat scan, mortality within 30 days, and thrombotic events within five days. Odds ratios (ORs) with 95% confidence intervals (CI) were calculated using propensity score-overlap weighted logistic regression. RESULTS: The study included 107 andexanet alfa (96.6% low dose) and 95 4F-PCC patients (79.3% receiving a 25 unit/kg dose). After propensity score-overlap weighting, mean age was 79 years, GCS was 14, time from initial scan to reversal initiation was 2.3 h, and time from reversal to repeat scan was 12.2 h in both arms. Atrial fibrillation was present in 86% of patients. Most ICHs were single compartment (78%), trauma-related (61%), and involved the intracerebral and/or intraventricular space(s) (53%). ICH size was ≥ 10 mL in volume (intracerebral and/or ventricular) or ≥ 10 mm in thickness (subdural or subarachnoid) in 22% of patients and infratentorial in 15%. Andexanet alfa was associated with greater odds of achieving hemostatic effectiveness (85.8% vs. 68.1%; OR 2.73; 95% CI 1.16-6.42) and decreased odds of mortality (7.9% vs. 19.6%; OR 0.36; 95% CI 0.13-0.98) versus 4F-PCC. Two thrombotic events occurred with andexanet alfa and none with 4F-PCC. CONCLUSIONS: In this indirect comparison of patients with an apixaban- or rivaroxaban-associated ICH, andexanet alfa was associated with better hemostatic effectiveness and improved survival compared to 4F-PCC. Trial registration NCT02329327; registration date: December 31, 2014.

Direct oral anticoagulants for cancer-associated venous thromboembolisms: a systematic review and network meta-analysis.

BACKGROUND: Several recent randomised controlled trials (RCT) have investigated the use of direct oral anticoagulants (DOAC) in the treatment of malignancy-associated venous thromboembolism (VTE). AIMS: This meta-analysis combines all RCT data to determine the risks of recurrent VTE and bleeding with DOAC in patients with malignancy-associated VTE compared with low-molecular-weight heparin (LMWH). METHODS: The study followed PRISMA guidelines. MEDLINE, EMBASE and CENTRAL were systematically searched from inception to 1 April 2020. References of reviews and relevant conference proceedings were searched by hand. Two authors independently evaluated study eligibility, extracted data and assessed risk of bias. Direct and indirect meta-analyses were performed. RESULTS: In four RCT with low risk of bias (2907 patients), high certainty evidence suggested that DOAC had a 37% reduction in risk of recurrent VTE compared with LMWH (direct pooled risk ratio (RR) 0.63; 95% confidence interval (CI) 0.44-0.91; I2 = 28%). No significant difference was observed in the risk of major bleeding with DOAC compared with LMWH (RR 1.31; 95% CI 0.83-2.07; I2 = 22%; moderate certainty evidence), including in patients in gastrointestinal and genitourinary malignancy. An increased risk of combined major or clinically relevant non-major bleeding was seen with DOAC (RR 1.52; 95% CI 1.09-2.12; I2 = 51%; low certainty evidence). Apixaban had the highest probability of being ranked the most effective and least bleeding risk among the DOAC. CONCLUSION: DOAC are effective in treating malignancy associated VTE; however, caution is required in patients with high risk of bleeding. Apixaban had lower risk of bleeding compared to other DOAC in this population.

Indirect antiplatelet effects of rivaroxaban in a patient with intracranial hemorrhage: An underappreciated coagulopathy of factor Xa inhibitors?

Rivaroxaban is a direct oral anticoagulant (DOAC) used for prophylaxis and treatment of many prothrombotic states. The anticoagulation effects of rivaroxaban are produced by selectively binding and inhibiting factor Xa, causing delayed thrombin generation. Additionally, the delay in thrombin generation produces an indirect, dose dependent antiplatelet effect via reduction in tissue factor platelet aggregation. As with any anticoagulant, rivaroxaban use increases a patient's risk for major and minor hemorrhagic events. With mortality rates reported as high as 25% for those who experience an intracranial hemorrhage (ICH), immediate mitigation of hematoma and hemorrhage volume expansion is imperative. Management strategies include utilizing prothrombin complex concentrates (PCC) and factor Xa inhibitor specific antidotes, such as coagulation factor Xa recombinant, inactivated-zhzo. Routine monitoring or management of DOAC induced antiplatelet effects is ill-defined and not a part of routine standard of care. We report the first case, to our knowledge, of rivaroxaban's indirect antiplatelet effects identified by platelet function assays and managed with four-factor PCC and desmopressin in a patient experiencing an ICH. Further exploration is needed to determine the true clinical impact attributed to rivaroxaban's antiplatelet effects.

Andexanet alfa versus four-factor prothrombin complex concentrate for the reversal of apixaban- or rivaroxaban-associated intracranial hemorrhages.

BACKGROUND: Existing research recommends either andexanet alfa (AA) or four-factor prothrombin complex concentrate (4F-PCC) as an antidote for major bleeding events due to apixaban or rivaroxaban. Currently, there is limited published research that directly compares the risks and benefits of the two agents in patients with oral factor Xa inhibitor related traumatic and spontaneous intracerebral hemorrhages. Additional head-to-head data is needed to support favoring either AA or 4F-PCC when it comes to efficacy, safety, and cost. METHODS: A retrospective chart review was conducted to assess patients admitted to a multi-center healthcare system and a stand-alone teaching hospital in central Florida from June 2016 to December 2020. Patients included in the study were at least 18 years of age, taking apixaban or rivaroxaban prior to admission, had radiographical evidence of an intracranial hemorrhage, and received either AA or 4F-PCC as a reversal agent. The primary outcome analyzed was the level of excellent hemostasis achieved, based on a standardized rating system for effective hemostasis defined by the International Society of Thrombosis and Hemostasis (ISTH), after administration of AA or 4F-PCC. Secondary outcomes analyzed included changes in the initial hemorrhage volume as reported on computed tomography (CT) scan and at 12 to 24 h post treatment, rate of thromboembolic events, rate of inpatient mortality, and total cost of treatment after AA or 4F-PCC administration. RESULTS: A total of 109 patients were included in the study with 47 in the AA group (43.1%) and 62 in the 4F-PCC group (56.9%). There were no statistically significant differences between AA and 4F-PCC in terms of the primary and secondary outcomes with the exception of total cost of treatment. The level of excellent hemostasis achieved after reversal administration of AA was seen in 27 patients (71.1%) and 41 patients (70.7%) after 4F-PCC administration (p = 1, p adjusted = 0.654 after controlling for age, ICH score, regional mass effect, and midline shift). There was no statistically significant difference in the median percentage change in hemorrhagic volume from baseline to 12-24 h after reversal treatment (0 [-0.17--0.24] vs. 0 [-0.021-0.29], p = 0.439, adjusted p = 0.601) in the AA and 4F-PCC groups, respectively. The total incidence of thromboembolic events (4 [8.5%] vs. 6 [9.7%], p = 1, adjusted p = 0.973) and rate of inpatient mortality was similar between the two groups (16 [34.0%] vs. 13 [21.0%], p = 0.134, adjusted p = 0.283). A statistically significant difference was observed with the total cost of reversal treatment: $23,602 for treatment with AA and $6692 for treatment with 4F-PCC. CONCLUSIONS: No statistically significant differences were identified in primary or secondary outcomes between the two agents with the exception of total treatment cost. There is insufficient evidence based on this study to recommend AA over 4F-PCC for patients with intracranial hemorrhages associated with the use of apixaban or rivaroxaban.

Four-factor prothrombin complex concentrate administration after expanding intracranial hemorrhage status post administration of andexanet alfa.

BACKGROUND: With respect to reversal of life threatening bleeds associated with the use of oral factor Xa inhibitors, current guidelines provide few recommendations for a preferred reversal agent. When the initial reversal agent fails to achieve the desired hemostatic response, there is little to no recommendations for the use of additional reversal agents. CASE REPORT: An 86-year-old female on apixaban (ELIQUIS) for atrial fibrillation, presented from an outside hospital due to a spontaneous intracranial hemorrhage (sICH). Computed tomography (CT) scan revealed multifocal left sided sICH. Due to use of apixaban in the setting to sICH, patient received andexanet alfa (AA) for reversal. Patient was then transferred and upon arrival to receiving emergency department (ED), repeat CT scans showed an expanding sICH, progression of midline shift, and low-molecular weight heparin levels that were ≥ 2 international units (IU) per milliliter (mL), indicating therapeutic apixaban activity. The patient was subsequently given four-factor prothrombin complex concentrate (4F-PCC). WHY AN EMERGENCY MEDICINE PHYSICIAN SHOULD BE AWARE OF THIS INCLUDE THE FOLLOWING KEY POINTS.

Impact of Factor Xa Inhibitor Reversal with Prothrombin Complex Concentrate in Patients with Traumatic Brain Injuries.

BACKGROUND: Anticoagulant use prior to trauma has been associated with increased incidence of traumatic brain injury (TBI), intracranial hemorrhage (ICH) progression, and mortality. Prothrombin complex concentrates (PCCs) are commonly used as off-label treatments for factor Xa inhibitor-associated life-threatening hemorrhage. At this time, there is no consensus regarding appropriate indication, target dose, or outcomes of PCC administration in patients presenting with traumatic ICH. This study seeks to evaluate the impact of reversal with PCC on hemorrhage progression and outcomes in patients with TBI on preinjury factor Xa inhibitors. METHODS: This single-center retrospective cohort study included patients ≥ 18 years presenting with an acute TBI of any severity on apixaban or rivaroxaban from September 1, 2016, to September 1, 2019. Patients were grouped on the basis of receipt of PCCs for reversal (i.e., reversal or no reversal). Exclusion criteria included spontaneous ICH or known coagulopathy. Propensity score matching was conducted with the following variables: age, Abbreviated Injury Scale (head) score, and Charlson Comorbidity Index score. The primary outcome was hemorrhage stability within 48 h. Secondary outcomes included degree of hemorrhage progression, in-hospital mortality, discharge disposition, and incidence of thromboembolic events. RESULTS: Of the 115 patients meeting inclusion criteria, 84 were included in the propensity score matched data set. Baseline characteristics, comorbidities, and TBI severity were similar. The majority of patients in the reversal group (35 [83.3%]) and the no reversal (NR) group (40 [95.2%]) experienced a mild TBI (admission Glasgow Coma Scale score of 14 to 15). In the reversal group, patients received 34.3 units/kg activated PCC, 30.5 units/kg four-factor PCC, or 54.9 units/kg four-factor PCC and activated PCC on average. There was no difference observed in the incidence of hemorrhage progression (10.8% NR vs. 15.0% reversal; p = 0.739) or in median change in ICH volume (0 mL NR vs. 1 mL reversal; p = 0.2199) between groups. Additionally, reversal did not affect in-hospital mortality (3 [7.1%] NR vs. 4 [9.5%] reversal; p > 0.999). One patient in the reversal group developed a deep vein thrombosis (DVT) during the hospitalization; however, this did not result in a statistically significant difference in the occurrence of DVT (p > 0.999). CONCLUSIONS: This study demonstrated that PCC used for the treatment of factor Xa inhibitor-associated ICH related to mild TBI did not significantly impact the incidence or degree of hemorrhage progression, and PCC treatment did not result in increased thromboembolic events.

Pharmacological Difference Between Platelet Aggregations in Cardioembolic Stroke Patients with Direct Oral Anticoagulants: A Pilot Study.

Background Selecting the appropriate direct oral anticoagulants (DOACs) for embolic ischemic stroke patients, especially on concurrent antiplatelet therapy, is important. However, a limited number of studies have reported on the pharmacological differences in platelet aggregation of each DOAC. We aimed to evaluate the antiplatelet effects of selected DOACs, by comparing dabigatran (a direct oral thrombin inhibitor) and factor Xa (FXa) inhibitors (apixaban and rivaroxaban) in patients who had suffered a cardioembolic stroke. Methods We retrospectively evaluated 12 patients diagnosed with a cardioembolic stroke who took any DOAC without an antiplatelet drug and underwent platelet aggregation tests within 60 days from the onset of symptoms. The platelet aggregation tests were analyzed by both light transmission aggregometry and VerifyNow®. Results Six patients (50%) took dabigatran, while the other six (50%) took an FXa inhibitor (n = 4 for apixaban and n = 2 for rivaroxaban). From the light transmission aggregometry analysis, it was found that the maximal extent of aggregation for adenosine diphosphate (ADP) was significantly higher with dabigatran than with FXa inhibitors, and the ED50 value of ADP on platelet aggregation was significantly lower with dabigatran than with FXa inhibitors. Moreover, the VerifyNow® analyses revealed that P2Y12 reaction units were significantly higher with dabigatran than with FXa inhibitors. Conclusions Dabigatran had little impact on platelet aggregation compared to FXa inhibitors in patients who had suffered a cardioembolic stroke with atrial fibrillation, and who took DOACs for secondary prevention within 60 days from the onset.

Factor Xa Inhibition for the Treatment of Venous Thromboembolism Associated With Cancer: A Meta-Analysis of the Randomised Controlled Trials.

BACKGROUND: Venous thromboembolism (VTE) is a common cause of morbidity and mortality in cancer patients. Until recently, guidelines recommended the use of low-molecular weight heparin (LMWH) as standard of care for VTE in patients with cancer. Despite the proven efficacy of direct oral anticoagulants (DOACs) for treatment of VTE, there is equipoise supporting their use in cancer patients. METHODS: A systematic review of PubMed, Medline and EMBASE identified four randomised controlled trials (RCTs) in patients with cancer and VTE comparing a factor Xa inhibitor (FXaI) to LMWH. A meta-analysis was performed with a primary outcome of VTE recurrence and key secondary outcomes of major bleeding, clinically relevant non-major bleeding (CRNMB) and gastrointestinal (GI) bleeding. RESULTS: Four RCTs with 2,907 patients were included. 1,451 patients were randomised to FXaI and 1,456 to LMWH. VTE recurrence was lower in the FXaI group (RR 0.62, 95%CI 0.44-0.87; p=0.01; I2=24.90), with an absolute risk difference of -4% equating to a number needed to treat of 25 for prevention of recurrent VTE with FXaI. No significant difference in major bleeding was noted between groups (RR 1.33, 95%CI 0.84-2.11; p=0.23). Rates of GI bleeding (RR 1.87, 95%CI 1.06-3.29; p=0.03) and CRNMB (RR 1.57, 95%CI 1.11-2.23; p=0.01) were greater with FXaIs. CONCLUSION: In patients with cancer and VTE, the rate of VTE recurrence was significantly lower with FXaI than with LMWH without an increased risk of major bleeding. Our data supports the use of FXaIs as the standard of care for the treatment of VTE in this population.

Hemostatic Efficacy and Anti-FXa (Factor Xa) Reversal With Andexanet Alfa in Intracranial Hemorrhage: ANNEXA-4 Substudy.

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.

Increased bleeding risk associated with concurrent vascular endothelial growth factor receptor tyrosine kinase inhibitors and low-molecular-weight heparin.

BACKGROUND: Some cancer patients who are diagnosed with thromboembolism may require dual treatment with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) and factor Xa inhibitors (low-molecular-weight heparin [LMWH] or direct oral anticoagulants [DOACs]). However, to the authors' knowledge, the safety of such combinations has not been well characterized. METHODS: Patients with advanced cancer who were treated with concurrent VEGFR TKIs and factor Xa inhibitors between 2010 and 2018 at The Ohio State University Comprehensive Cancer Center were included. Charts were reviewed retrospectively for clinically significant bleeding events occurring during concurrent treatment compared with those occurring during factor Xa inhibitor therapy alone, using each patient as their own control. The Fisher exact test was used to compare distribution of bleeding severities. The Cox proportional hazards model was used to compare bleeding risk between groups. RESULTS: Among 86 patients, there were 29 clinically significant bleeding events (including 8 major bleeding events) reported during concurrent treatment and 17 events (including 4 major bleeding events) reported during factor Xa inhibitor therapy alone over a median follow-up of 63 days. Concurrent treatment was associated with significantly higher risks of overall bleeding (hazard ratio, 2.45; 95% confidence interval, 1.28-4.69 [P = .007]) and first-onset bleeding (hazard ratio, 2.23; 95% confidence interval, 1.13-4.42 [P = .02]). Analysis of 6-month bleeding risk and the subgroups of patients treated with concurrent TKIs and LMWH versus LMWH alone demonstrated a similar trend. The sample size was inadequate for comparisons between treatment with concurrent TKIs and DOACs versus DOACs alone. CONCLUSIONS: Concurrent treatment with VEGFR TKIs and LMWH was found to be associated with a significantly increased risk of bleeding events when compared with LMWH therapy alone.

Individual Patient Data from the Pivotal Randomized Controlled Trials of Non-Vitamin K Antagonist Oral Anticoagulants in Patients with Atrial Fibrillation (COMBINE AF): Design and Rationale: From the COMBINE AF (A Collaboration between Multiple institutions to Better Investigate Non-vitamin K antagonist oral anticoagulant use in Atrial Fibrillation) Investigators.

BACKGROUND: Non-vitamin K antagonist oral anticoagulants (NOACs) are the preferred class of medications for prevention of stroke and systemic embolism in patients with atrial fibrillation unless contraindications exist. Five large, international, randomized, controlled trials of NOACs versus either warfarin or aspirin have been completed to date. DESIGN: COMBINE AF incorporates de-identified individual patient data from 77,282 patients with atrial fibrillation at risk for stroke randomized to NOAC, warfarin, or aspirin from 5 pivotal randomized controlled trials. All patients randomized in the constituent trials are included. Variables common to ≥3 of the constituent trials are included in the master database. Individual trial data sets from the 4 coordinating centers were combined at the Duke Clinical Research Institute. The final database will be securely shared with the 4 academic coordinating centers. The combined master database will be used to perform statistical analyses aimed at better understanding underlying risk factors and outcomes in patients with atrial fibrillation treated with oral anticoagulants, with a special focus on patient subgroups and uncommon outcomes. The initial analysis from COMBINE AF will be a network meta-analysis investigating the relative efficacy and safety of pooled higher-dose NOACs versus pooled lower-dose NOACs versus warfarin with respect to multiple time-to-event efficacy and safety outcomes. COMBINE AF is registered with PROSPERO (CRD42020178771). CONCLUSION: In conclusion, COMBINE AF provides a rich and robust database consisting of individual patient data and will offer opportunities to investigate oral anticoagulants across many patient subgroups. Data sharing and collaboration across academic institutions and investigators will serve as overarching themes.

Effectiveness and Safety of Direct Oral Anticoagulants in an Asian Population with Atrial Fibrillation Undergoing Dialysis: A Population-Based Cohort Study and Meta-Analysis.

PURPOSE: Whether direct oral anticoagulants (DOACs) are more effective and safer than warfarin among Asian patients with non-valvular atrial fibrillation (NVAF) undergoing dialysis remains unclear. METHODS: We first compared the risks of ischemic stroke/systemic embolism (IS/SE) and major bleeding associated with DOACs compared with warfarin, in NVAF Asians undergoing dialysis using the Taiwan National Health Insurance Research Database (NHIRD) (Aim 1). Next, we searched PubMed and Medline from January 1, 2010 until January 31, 2020, to perform a systematic review and meta-analysis of all observational real-world studies comparing DOACs with warfarin specifically focused on NVAF patients with stage 4 or 5 chronic kidney disease undergoing dialysis (Aim 2). Finally, we tested the hypothesis whether AF patients undergoing dialysis treated with OACs (warfarin and DOACs) would be associated with lower risk of adverse clinical outcomes as compared to those without OACs using the Taiwan NHIRD (Aim 3). RESULTS: From June 1, 2012, to December 31, 2017, a total of 3237 and 9263 NVAF patients comorbid with ESRD receiving oral anticoagulant (OACs) (490 on DOAC, 2747 on warfarin) or no OACs, respectively, were enrolled. Propensity score matching was used to balance covariates across the study groups. For the comparison of DOAC vs. warfarin (Aim 1), DOACs had comparable risks of IS/SE and major bleeding to warfarin in our present cohort. From the original 85 results retrieved, nine studies (including our study) with a total of 6490 and 22,494 patients treated with DOACs and warfarin were included in the meta-analysis, respectively. There were 5343 (82%) and 20,337 (90%) patients treated with DOACs and warfarin undergoing dialysis, respectively. The pooled meta-analysis also indicated no difference of the effectiveness (HR:0.90; [95%CI:0.74-1.10]; P = 0.32) and safety outcomes (HR:0.75; [95%CI:0.54-1.05]; P = 0.09) between DOACs and warfarin (Aim 2). For the comparison of OAC (+) vs. OAC (-) (Aim 3), OAC-treatment was associated with a higher risk of IS/SE (hazard ratio (HR):1.54; [95% confidential interval (CI):1.29-1.84];P < 0.0001) and comparable risk of major bleeding compared to those without OAC treatment. CONCLUSIONS: DOACs did not provide benefit over warfarin regarding effectiveness and safety in AF patients undergoing dialysis. The use of OAC was not associated with a lower risk of IS/SE in ESRD AF patients when compared to those without OAC use.

From basic science to life-saving therapy: the rationale, and drug discovery efforts that led to the direct factor Xa inhibitor eliquis.

Over the past few decades, drug discovery directed at the treatment and prevention of thromboembolic diseases has been challenged by the need to balance robust efficacy with improved safety relative to the standard of care. To this end, the most impactful advance to date has been the discovery and development of oral factor Xa inhibitors. In this essay, a brief account of the program that culminated in the discovery of Eliquis (apixaban) and the commitment to identify a compound with an optimal profile are described.