Evaluation of oral factor Xa inhibitor-associated extracranial bleeding reversal with andexanet alfa

Co-administration of Four-Factor Prothrombin Complex Concentrate With Andexanet alfa for Reversal of Nontraumatic Intracranial Hemorrhage

Objective: Andexanet alfa is approved for the reversal of life-threatening or uncontrolled bleeding due to factor-Xa inhibitors. Data are limited on outcomes for patients who receive both andexanet alfa and 4-factor prothrombin complex concentrate (4F-PCC). The aim of this case series is to evaluate the safety and efficacy outcomes in patients receiving the two agents in combination. Methods: Electronic medical records of patients who received both 4F-PCC and andexanet alfa for nontraumatic intracranial hemorrhage from January 2019 to March 2022 were retrospectively reviewed. Hemostatic efficacy and complications related to concurrent use of 4F-PCC with andexanet alfa were documented. Results: Nine patients received 4F-PCC and andexanet alfa for reversal of factor Xa inhibitor-associated intracranial bleeding, eight of whom required reversal of apixaban. Of these nine patients, five patients died within 28 days for a 56% incidence of mortality. The average time from 4F-PCC administration to andexanet alfa administration was 3 hours and 9 minutes. Most doses of andexanet alfa were given for concern for bleed expansion after 4F-PCC administration. Hemostatic efficacy based on stability of repeat computed tomography scans post-administration of both agents was found in six patients (66.67%), with a 55.56% n incidence of thromboembolism, including two pulmonary embolisms, two deep vein thromboses, and one renal artery thrombosis. Conclusion: Risks and benefits should be weighed to determine if there is benefit to adding andexanet alfa to 4F-PCC in patients with incomplete hemostasis and life-threatening hemorrhage. The combination of andexanet alfa and 4F-PCC may increase the risk of thrombotic complications without improving mortality.

Design and rationale for REVERXaL: A real-world study of patients with factor Xa inhibitor-associated major bleeds

BACKGROUND

The prevalence of anticoagulation treatment is increasing as an aging global population faces a high burden of cardiovascular comorbidities. Direct oral anticoagulants, including factor Xa inhibitors (FXai), are replacing vitamin K antagonists as the most commonly prescribed treatment for reducing risk of thrombotic events. While the risk of FXai-associated spontaneous bleeds is established, less is understood about their management and the effect of treatment on clinical and patient-reported outcomes. The primary objectives of the REVERXaL study are to describe patient characteristics, health care interventions during the acute-care phase, in-hospital outcomes, and associations between timing of reversal/replacement agent administration and in-hospital outcomes. Secondary/exploratory objectives focus on clinical assessments and patient-reported outcome measures (PROMs) at 30 and 90 days.

METHODS

REVERXaL is a multinational, observational study of hospitalized patients with FXai-associated major bleeds in Germany, Japan, the United Kingdom, and the United States. The study includes 2 cohorts of approximately 2000 patients each. Cohort A is a historic cohort for whom medical chart data will be collected from hospitalization to discharge for patients admitted for major bleeds during FXai use within 2 years prior to enrollment of Cohort B. Cohort B will prospectively enroll patients administered any reversal/replacement agent during hospitalization to manage FXai-associated major bleeds and will include the collection of clinical outcomes and PROMs data over 3 months.

CONCLUSIONS

REVERXaL will generate insights on patient characteristics, treatment approaches, and associated outcomes in patients hospitalized with FXai-associated major bleeds. These data may inform clinical practice and streamline treatment pathways in this population.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; unique identifier: NCT06147830.

Emergency medicine updates: Lower gastrointestinal bleeding

INTRODUCTION

Lower gastrointestinal bleeding (LGIB) is a condition commonly seen in the emergency department. Therefore, it is important for emergency medicine clinicians to be aware of the current evidence regarding the diagnosis and management of this disease.

OBJECTIVE

This paper evaluates key evidence-based updates concerning LGIB for the emergency clinician.

DISCUSSION

LGIB is most commonly due to diverticulosis or anorectal disease, though there are a variety of etiologies. The majority of cases resolve spontaneously, but patients can have severe bleeding resulting in hemodynamic instability. Initial evaluation should focus on patient hemodynamics, the severity of bleeding, and differentiating upper gastrointestinal bleeding from LGIB. Factors associated with LGIB include prior history of LGIB, age over 50 years, and presence of blood clots per rectum. Computed tomography angiography is the imaging modality of choice in those with severe bleeding to diagnose the source of bleeding and guide management when embolization is indicated. Among stable patients without severe bleeding, colonoscopy is the recommended modality for diagnosis and management. A transfusion threshold of 7 g/dL hemoglobin is recommended based on recent data and guidelines (8 g/dL in those with myocardial ischemia), though patients with severe bleeding and hemodynamic instability should undergo emergent transfusion. Anticoagulation reversal may be necessary. If bleeding does not resolve, embolization or endoscopic therapies are necessary. There are several risk scores that can predict the risk of adverse outcomes; however, these scores should not replace clinical judgment in determining patient disposition.

CONCLUSIONS

An understanding of literature updates can improve the care of patients with LGIB.

Clinical guideline on reversal of direct oral anticoagulants in patients with life threatening bleeding

BACKGROUND

Anticoagulation is essential for the treatment and prevention of thromboembolic events. Current guidelines recommend direct oral anticoagulants (DOACs) over vitamin K antagonists in DOAC-eligible patients. The major complication of anticoagulation is serious or life-threatening haemorrhage, which may necessitate prompt haemostatic intervention. Reversal of DOACs may also be required for patients in need of urgent invasive procedures. This guideline from the European Society of Anaesthesiology and Intensive Care (ESAIC) aims to provide evidence-based recommendations and suggestions on how to manage patients on DOACs undergoing urgent or emergency procedures including the treatment of DOAC-induced bleeding.

DESIGN

A systematic literature search was performed, examining four drug comparators (dabigatran, rivaroxaban, apixaban, edoxaban) and clinical scenarios ranging from planned to emergency surgery with the outcomes of mortality, haematoma growth and thromboembolic complications. The GRADE (Grading of Recommendations, Assessment, Development and Evaluation) methodology was used to assess the methodological quality of the included studies. Consensus on the wording of the recommendations was achieved by a Delphi process.

RESULTS

So far, no results from prospective randomised trials comparing two active comparators (e.g. a direct reversal agent and an unspecific haemostatic agent such as prothrombin complex concentrate: PCC) have been published yet and the majority of publications were uncontrolled and observational studies. Thus, the certainty of evidence was assessed to be either low or very low (GRADE C). Thirty-five recommendations and clinical practice statements were developed. During the Delphi process, strong consensus (>90% agreement) was achieved in 97.1% of recommendations and consensus (75 to 90% agreement) in 2.9%.

DISCUSSION

DOAC-specific coagulation monitoring may help in patients at risk for elevated DOAC levels, whereas global coagulation tests are not recommended to exclude clinically relevant DOAC levels. In urgent clinical situations, haemostatic treatment using either the direct reversal or nonspecific haemostatic agents should be started without waiting for DOAC level monitoring. DOAC levels above 50 ng ml-1 may be considered clinically relevant necessitating haemostatic treatment before urgent or emergency procedures. Before cardiac surgery under activated factor Xa (FXa) inhibitors, the use of andexanet alfa is not recommended because of inhibition of unfractionated heparin, which is needed for extracorporeal circulation. In the situation of DOAC overdose without bleeding, no haemostatic intervention is suggested, instead measures to eliminate the DOACs should be taken. Due to the lack of published results from comparative prospective, randomised studies, the superiority of reversal treatment strategy vs. a nonspecific haemostatic treatment is unclear for most urgent and emergency procedures and bleeding. Due to the paucity of clinical data, no recommendations for the use of recombinant activated factor VII as a nonspecific haemostatic agent can be given.

CONCLUSION

In the clinical scenarios of DOAC intake before urgent procedures and DOAC-induced bleeding, practitioners should evaluate the risk of bleeding of the procedure and the severity of the DOAC-induced bleeding before initiating treatment. Optimal reversal strategy remains to be determined in future trials for most clinical settings.

The use of andexanet alfa vs. 4-factor prothrombin complex concentrates in the setting of life-threatening intracranial hemorrhage

OBJECTIVE

Andexanet alfa is a targeted reversal agent for life threatening hemorrhage associated with direct acting oral anticoagulants (DOACs), but there is uncertainty regarding the benefit when compared to 4-factor prothrombin complex concentrate (4F-PCC) for this indication. We investigated the clinical outcomes and cost associated with reversal of DOACs in the setting of life-threatening intracranial hemorrhage (ICH).

METHODS

A retrospective evaluation was conducted to evaluate patients with ICH in the setting of anticoagulation with DOAC from 9/1/2013 to 4/30/2020. Patients were included in the study if they received reversal with either andexanet alfa or 4F-PCC.

RESULTS

Eighty-nine patients were included in the study. There was no statistically significant difference in 30-day mortality between patients who received andexanet alfa or 4F-PCC (52% vs. 35%, P  = 0.14). Radiographic stability of bleed was identified in 57% of patients receiving andexanet alfa vs. 58% of patients receiving 4F-PCC ( P  = 0.93). Median length of stay was not different between the andexanet alfa and 4F-PCC populations (7 days [IQR 6 - 12] vs. 6 days [IQR 3-12], P  = 0.66). Median cost of reversal agent was higher in patients receiving andexanet alfa compared to 4F-PCC ($15 000 [IQR 15 000-$27 000] vs. $11 650 [IQR $8567-$14 149]).

CONCLUSION

Among patients with life-threatening intracranial hemorrhage in the setting of DOAC therapy, no clinical differences were observed with respect to selection of reversal agent. Prothrombin complex concentrates remain a viable alternative to reversal of DOAC therapy though multicenter, randomized, prospective studies are needed to further evaluate the role of 4F-PCC in the reversal of DOAC therapy.

Assessment of the hypoglycemic and anti-hemostasis effects of Paederia foetida (L.) in controlling diabetes and thrombophilia combining in vivo and computational analysis

Paederia foetida is valued for its folk medicinal properties. This research aimed to assess the acute toxicity, hypoglycemic and anti-hemostasis properties of the methanolic extract of P. foetida leaves (PFLE). Acute toxicity of PFLE was performed on a mice model. Hypoglycemic and anti-hemostasis properties of PFLE were investigated on normal and streptozotocin-induced mice models. Deep learning, molecular docking, density functional theory, and molecular simulation techniques were employed to understand the underlying mechanisms through in silico study. Oral administration of PFLE at a dosage of 300 µg/kg body weight (BW) showed no signs of toxicity. Treatment with PFLE (300 µg/kg/BW) for 14 days resulted in a hypoglycemic condition and a 30.47% increase in body weight. Additionally, PFLE mixed with blood exhibited a 44.6% anti-hemostasis effect. Deep learning predicted the inhibitory concentration (pIC50, nM) of Cleomiscosins against SGLT2 and FXa to be 7.478 and 6.017, respectively. Molecular docking analysis revealed strong binding interactions of Cleomiscosins with crucial residues of the target proteins, exhibiting binding energies of -8.2 kcal/mol and -7.1 kcal/mol, respectively. ADME/Tox predictions indicated favorable pharmacokinetic properties of Cleomiscosins, and DFT calculations of frontier molecular orbitals analyzed the stability and reactivity of these compounds. Molecular simulation dynamics, principal component analysis and MM-PBSA calculation demonstrated the stable, compact, and rigid nature of the protein-ligand complexes. The methanolic PFLE exhibited significant hypoglycemic and anti-hemostasis properties. Cleomiscosin may have inhibitory properties for the development of novel drugs to manage diabetes and thrombophilia in the near future.

Real world utilization of Andexanet alfa in the management of oral factor Xa inhibitor-associated gastrointestinal bleeding

BACKGROUND

Andexanet alfa (AA) is approved for reversal of factor Xa inhibitor (FXaI) bleeds; however, there are limited reports of its use for gastrointestinal bleeding (GIB) in real-world populations. The objective of this study was to report real-world utilization and evaluation of the effectiveness of AA for FXaI-associated GIB.

METHODS

This retrospective cohort study including consecutive patients receiving AA for FXaI-associated GIB (7/2018-2/2021). Demographics, blood product administration, hemostatic efficacy, rebleeding, thrombosis, and mortality rates were collected. Hemostatic efficacy (HE), based on corrected hemoglobin at 12 h compared to baseline, was categorized as excellent (<10% decrease), good (≤ 20% decrease), or poor (>20% decrease, > 2 units of additional coagulation intervention or death prior to repeat hemoglobin). Comparative transfusion requirements between efficacy groups was assessed by Wilcoxon-Rank test.

RESULTS

Twenty-two patients were included (64% male, median (IQR) age 76 years (67, 80). Most patients (59%, n = 13) were on apixaban, and the primary anticoagulation indication was atrial fibrillation (64%, n = 14). Median initial hemoglobin was 7.5 g/dL (IQR 6.4, 8.8) and 50% (n = 11) were upper GIB. Hemostatic efficacy was excellent in 46% (n = 10), good in 23% (n = 5), and poor in 32% (n = 7). There was no statistically significant difference in red blood cells (RBCs) received between those with excellent/good hemostasis (median 2, IQR 1 to 2) and those with poor hemostasis (median 4, IQR 1.5 to 4.5). Two patients (9%) had arterial thrombotic events within 30 days of reversal.

CONCLUSION

In this multicenter, single arm, real-world observational analysis of patients with factor Xa inhibitor associated GIB most patients achieved good hemostasis following administration of AA. There was a 9% 30-day thrombotic event rate. The lack of a control group limits the strength of the conclusions that can be drawn from this study.

Case Report: Extended Duration Andexanet Alfa Infusion in a Surgical Trauma Patient

Background: Andexanet alfa (andexanet) is the only FDA-approved medication for reversal of apixaban and rivaroxaban anticoagulation for life-threatening or uncontrolled bleeding. Infusion modifications may be required in surgical patients undergoing prolonged operative intervention but have not previously been described. Case Report: A 78-year-old woman on rivaroxaban for atrial fibrillation was admitted to the trauma service for a mechanical fall, sustaining a T4 burst fracture with severe canal stenosis and spinal cord edema resulting in loss of strength and sensation in her legs. Clinically relevant rivaroxaban activity was verified with an elevated low molecular weight heparin anti-factor Xa assay, and laboratory confirmed coagulopathy was demonstrated by a prolonged prothrombin time, thromboelastography (TEG) R-time, and activated clotting time (ACT). The patient required urgent surgical intervention for spinal fixation. Given the expected prolonged duration of the procedure, standard dose andexanet was initiated with a prolonged infusion at half the standard rate during the operation. The procedure was successful and intraoperative TEGs demonstrated normalization of R-time and ACT throughout the procedure. The patient did not experience any complications postoperatively and successfully discharged to inpatient rehabilitation. Conclusion: Modifications to the andexanet infusion may be required in surgical patients requiring rivaroxaban reversal for a prolonged procedure. Further data are needed to determine the optimal approach to infusion modification.

Recommendations for the use of andexanet alfa in the management of bleeding in patients on oral factor Xa inhibitors in Switzerland: Guideline from the Working Party Hemostasis of the Swiss Society of Hematology

Anticoagulants are essential in preventing and treating thrombosis. Unfortunately, their use is accompanied by an enhanced risk of bleeding. Since the introduction of direct oral anticoagulants (DOACs), the risk of major bleeding has been reduced but not eliminated. Major bleeding events related to the use of factor Xa inhibitors can be challenging to manage. In recent years, four-factor prothrombin complex concentrates have been used in patients with severe bleeding taking oral direct factor Xa inhibitors (apixaban, edoxaban and rivaroxaban). Andexanet alfa (OndexxyaTM, AstraZeneca AG) is a specially designed recombinant version of human factor Xa that acts as a decoy receptor to reverse the effects of factor Xa inhibitors. Since 2 December 2020, andexanet alfa has been used in Switzerland for adult patients receiving apixaban or rivaroxaban when reversal of anticoagulation is required because of life-threatening or uncontrolled bleeding. However, the use of andexanet alfa remains a challenge owing to its cost, the reported thrombotic complications and the fact that its efficacy mainly relates to intracranial haemorrhage. Moreover, the use of nonspecific reversal agents together with andexanet alfa is controversial. The present recommendations on the use of andexanet alfa in the management of bleeding in patients on factor Xa inhibitors in Switzerland were developed by a group of Swiss experts from the Working Party Hemostasis of the Swiss Society of Hematology. These recommendations aim to provide support to clinicians in their decision-making in the management of patients with major bleeding receiving factor Xa inhibitors.

Management of severe peri-operative bleeding: Guidelines from the European Society of Anaesthesiology and Intensive Care: Second update 2022

BACKGROUND

Management of peri-operative bleeding is complex and involves multiple assessment tools and strategies to ensure optimal patient care with the goal of reducing morbidity and mortality. These updated guidelines from the European Society of Anaesthesiology and Intensive Care (ESAIC) aim to provide an evidence-based set of recommendations for healthcare professionals to help ensure improved clinical management.

DESIGN

A systematic literature search from 2015 to 2021 of several electronic databases was performed without language restrictions. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to assess the methodological quality of the included studies and to formulate recommendations. A Delphi methodology was used to prepare a clinical practice guideline.

RESULTS

These searches identified 137 999 articles. All articles were assessed, and the existing 2017 guidelines were revised to incorporate new evidence. Sixteen recommendations derived from the systematic literature search, and four clinical guidances retained from previous ESAIC guidelines were formulated. Using the Delphi process on 253 sentences of guidance, strong consensus (>90% agreement) was achieved in 97% and consensus (75 to 90% agreement) in 3%.

DISCUSSION

Peri-operative bleeding management encompasses the patient's journey from the pre-operative state through the postoperative period. Along this journey, many features of the patient's pre-operative coagulation status, underlying comorbidities, general health and the procedures that they are undergoing need to be taken into account. Due to the many important aspects in peri-operative nontrauma bleeding management, guidance as to how best approach and treat each individual patient are key. Understanding which therapeutic approaches are most valuable at each timepoint can only enhance patient care, ensuring the best outcomes by reducing blood loss and, therefore, overall morbidity and mortality.

CONCLUSION

All healthcare professionals involved in the management of patients at risk for surgical bleeding should be aware of the current therapeutic options and approaches that are available to them. These guidelines aim to provide specific guidance for bleeding management in a variety of clinical situations.

Management of Patients With Acute Lower Gastrointestinal Bleeding: An Updated ACG Guideline

Acute lower gastrointestinal bleeding (LGIB) is a common reason for hospitalization in the United States and is associated with significant utilization of hospital resources, as well as considerable morbidity and mortality. These revised guidelines implement the Grading of Recommendations, Assessment, Development, and Evaluation methodology to propose recommendations for the use of risk stratification tools, thresholds for red blood cell transfusion, reversal agents for patients on anticoagulants, diagnostic testing including colonoscopy and computed tomography angiography (CTA), endoscopic therapeutic options, and management of antithrombotic medications after hospital discharge. Important changes since the previous iteration of this guideline include recommendations for the use of risk stratification tools to identify patients with LGIB at low risk of a hospital-based intervention, the role for reversal agents in patients with life-threatening LGIB on vitamin K antagonists and direct oral anticoagulants, the increasing role for CTA in patients with severe LGIB, and the management of patients who have a positive CTA. We recommend that most patients requiring inpatient colonoscopy undergo a nonurgent colonoscopy because performing an urgent colonoscopy within 24 hours of presentation has not been shown to improve important clinical outcomes such as rebleeding. Finally, we provide updated recommendations regarding resumption of antiplatelet and anticoagulant medications after cessation of LGIB.

Reversal of apixaban and rivaroxaban with andexanet alfa prior to invasive or surgical procedures

BACKGROUND

Outcomes following andexanet alfa reversal of factor Xa inhibitors in patients requiring urgent or emergent invasive procedures are lacking. This study aimed to describe efficacy and safety outcomes following andexanet alfa administration within 24 h of an invasive procedure.

METHODS

This single-center, observational, retrospective study included patients who received andexanet alfa within 24 h of an invasive or surgical procedure. The primary outcome was hemostatic efficacy graded as excellent, good, or poor using similar definitions to the ANNEXA-4 criteria. Secondary outcomes included hospital discharge disposition, intensive care unit (ICU) and hospital length of stay, 30-day mortality, 30-day thromboischemic event rates, and serum coagulation assay changes pre- and postreversal.

RESULTS

Forty-four patients met inclusion criteria; of these, 27 (62.8%) received apixaban and 16 (37.2%) were treated with rivaroxaban prior to admission. The indications for reversal were categorized as intracranial (n = 20 [45.5%]) or extracranial (n = 24 [54.5%]) sites. Majority of patients required emergent operative procedures (18 [40.9%]), followed by invasive device placement (10 [22.7%]) or arterial embolization (9 [20.5%]). Thirty-eight (86.4%) patients were able to be adequately graded for hemostatic efficacy. Overall, 30 (78.9%) patients achieved excellent or good hemostasis within 24 h after periprocedural administration of andexanet alfa (19 [82.6%] apixaban vs. 11 [78.6%] rivaroxaban; 12 [80.0%] intracranial events vs. 18 [78.3%] extracranial events). Discharge disposition was most often to a short- or long-term care facilities (27 [61.4%]). Thirty-day mortality and thromboischemic complications occurred in 15 (34.1%) and 12 (27.3%) patients, respectively. Prothrombin time and antifactor Xa assay results were significantly decreased after andexanet alfa administration (p < 0.05) while thromboelastogram assay values (reaction time, kinetic time, and activated clotting time) showed nonsignificant changes pre- versus postreversal.

CONCLUSION

Andexanet alfa may be used for urgent or emergent reversal of apixaban and rivaroxaban peri-procedurally with promising hemostatic outcomes. Further prospective, comparative clinical research is warranted.

Four-factor prothrombin complex concentrate plus andexanet alfa for reversal of factor Xa inhibitor-associated bleeding: Case series

DISCLAIMER

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

To manage factor Xa (FXa) inhibitor-associated bleeding, andexanet alfa or 4-factor prothrombin concentrate (4F-PCC) has been used to restore hemostasis. However, literature on the outcomes for patients who received both andexanet alfa and 4F-PCC is limited.

SUMMARY

We report a case series of 5 patients who received andexanet alfa plus 4F-PCC for reversal of FXa inhibitor-associated bleeding. Patients were included in this case series if they received both andexanet alfa and 4F-PCC for reversal of FXa inhibitor-associated bleeding. They were followed to either discharge or death, and in-hospital complications related to concurrent use of andexanet alfa and 4F-PCC were documented. We report an incidence of thromboembolism of 40% (2 of 5 cases) and an in-hospital mortality rate of 60% (3 of 5 cases). Taking these cases together with those in the existing literature, we found a total of 23 reported cases of safety outcomes with andexanet alfa plus 4F-PCC. The overall incidence of thromboembolism was 35% (8 of 23 cases).

CONCLUSION

This case series adds to the limited literature describing the outcomes for patients receiving andexanet alfa plus 4F-PCC. We encourage other institutions to report safety data on administering both agents.

Efficacy and Safety of Andexanet Alfa for Bleeding Caused by Factor Xa Inhibitors: A Systematic Review and Meta-Analysis

Direct oral anticoagulants (DOAC) including factor Xa inhibitors are associated with bleeding events which can lead to severe morbidity and mortality. Reversal agents like andexanet alfa (AA) and 4F-PCC (Four-factor prothrombin concentrate complex) are available for treating bleeding that occurs with DOAC therapy but a comparison on their efficacy is lacking. In this study, we analyzed the efficacy and safety of patients treated with andexanet alfa for bleeding events from DOAC. Databases were searched for relevant studies where AA was used to determine efficacy and safety in bleeding patients who were on factor Xa inhibitors. Published papers were screened independently by two authors. RevMan 5.4 (The Cochrane Collaboration, 2020) was used for data synthesis. Odds ratio (OR) and mean difference (MD) was used to estimate the outcome with a 95% confidence interval (CI). Among 1245 studies were identified after a thorough database search and three studies were included for analysis. AA resulted in lower odds of mortality compared to 4F- PCC (OR, 0.37; 95% CI, 0.20-0.71) among patients with intracerebral hemorrhage. There was no difference in thrombotic events between patients receiving AA and 4F-PCC (OR, 2.40; 95% CI, 0.36-15.84). No differences in length of hospital stay and intensive care unit (ICU) stay were seen between patients receiving AA and 4F-PCC. In conclusion, andexanet alfa reduced in-hospital mortality in patients who had bleeding due to factor Xa inhibitors compared to 4F-PCC. However, there were no differences in thrombotic events, length of ICU, and hospital stay between patients treated with AA and 4F-PCC.

Modeling the Clinical Implications of Andexanet Alfa in Factor Xa Inhibitor-Associated Intracerebral Hemorrhage

BACKGROUND AND OBJECTIVES

Andexanet alfa was recently approved as a reversal agent for the factor Xa inhibitors (FXais) apixaban and rivaroxaban, but its impact on long-term outcomes in FXai-associated intracerebral hemorrhage (ICH) is unknown. We aimed to explore potential clinical implications of andexanet alfa in FXai-associated ICH in this simulation study.

METHODS

We simulated potential downstream implications of andexanet alfa across a range of possible hemostatic effects using data from a single center that treats FXai-associated ICH with prothrombin complex concentrate (PCC). We determined baseline probabilities of inadequate hemostasis across patients taking FXai and those not taking FXai via multivariable regression models and then determined the probabilities of unfavorable 3-month outcome (modified Rankin Scale score 4-6) using models comprising established predictors and each patient's calculated probability of inadequate hemostasis. We applied bootstrapping with model parameters from this derivation cohort to simulate a range of hemostatic improvements and corresponding outcomes and then calculated absolute risk reduction (relative to PCC) and projected number needed to treat (NNT) to prevent 1 unfavorable outcome.

RESULTS

Training models using real-world patients (n = 603 total, 55 on FXai) had good accuracy in predicting inadequate hemostasis (area under the curve [AUC] 0.78) and unfavorable outcome (AUC 0.78). Inadequate hemostasis was strongly associated with unfavorable outcome (odds ratio 4.5, 95% confidence interval [CI] 2.0-9.9) and occurred in 11.4% of patients taking FXai. Across simulated patients taking FXai comparable to those in A Study in Participants With Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors (ANNEXA-4) study, predicted absolute risk reduction of unfavorable outcome was 4.9% (95% CI 1.3%-7.8%) when the probability of inadequate hemostasis was reduced by 33% and 7.4% (95% CI 2.0%-11.9%) at 50% reduction, translating to projected NNT of 21 (cumulative cost $519,750) and 14 ($346,500), respectively.

DISCUSSION

Even optimistic simulated hemostatic effects suggest that the costs and potential benefits of andexanet alfa should be carefully considered. Placebo-controlled randomized trials are needed before its use can definitively be recommended.

Difficulties Detecting Clinically Relevant Factor Xa Inhibitor Levels Prior to Reversal With Andexanet Alfa for Intracranial Hemorrhage

Coagulation factor Xa (recombinant), inactivated-zhzo (andexanet alfa) is approved for reversal of life-threatening bleeding with rivaroxaban and apixaban use. Clinical decision-making to initiate reversal is reliant on dose taken and timing of last dose. In practice, timing of last dose may be unknown, and the turnaround time for drug-specific anti-factor Xa levels at some institutions may be prolonged, leaving clinicians balancing a difficult decision with limited tools. This report includes a series of 3 patients who presented to our institution with an intracranial hemorrhage and received andexanet alfa for apixaban reversal. These cases highlight the challenges clinicians are facing when using andexanet alfa for emergent rivaroxaban or apixaban reversal when the timing of last dose is unknown, or patients fall outside of the recommended timeframe for use and clinically relevant drug levels are still suspected. Based on our experiences, we encourage other institutions to evaluate their abilities to rapidly and accurately detect the presence of clinically relevant rivaroxaban and apixaban levels when utilizing andexanet alfa.

Retrospective Comparison of Andexanet Alfa and 4-Factor Prothrombin Complex for Reversal of Factor Xa-Inhibitor Related Bleeding

The aim of this retrospective study was to compare andexanet alfa and 4-factor prothrombin complex (4F-PCC) for reversal of factor Xa (FXa)-inhibitor bleeding. Patients that received andexanet alfa for reversal were included. An equivalent number of patients administered 4F-PCC for FXa-inhibitor bleeding were randomly selected as historical controls. The primary outcome was effective hemostasis achievement within 12 h, defined using ANNEXA-4 criteria. Thromboembolic events and mortality within 30 days were also evaluated. A total of 32 patients were included. Baseline characteristics were not statistically different between andexanet alfa (n = 16) and 4F-PCC (n = 16). Intracranial bleeding was the primary reversal indication in 43.8% versus 62.5% of patients, respectively. Effective hemostasis was reached in 75.0% of andexanet alfa patients compared to 62.5% of 4F-PCC patients (P = .70). Thromboembolic events occurred in 4 (25.0%) patients and 3 (18.8%) patients, respectively (P = .99). Mortality incidence was 12.5% and 31.3%, respectively (P = .39). Andexanet alfa and 4F-PCC attained hemostasis in a majority of patients. A high, but a similar rate of thromboembolic events was seen with both treatments. Prospective studies are needed to elucidate comparative risks and benefits of the 2 agents.

Apixaban and rivaroxaban anti-Xa level utilization for guidance of administration of andexanet alfa: a case series

BACKGROUND

Andexanet alfa, a modified recombinant factor Xa (FXa), was FDA approved in 2018 for anticoagulant reversal in patients with life-threatening bleeding associated with FXa inhibitors (FXaI). The ANNEXA-4 investigators administered andexanet alfa to patients within an 18-h from last dose of oral FXaI. In practice, time from last dose is often unknown. Previous studies have shown that clearance of these agents may be impaired by renal and hepatic dysfunction, as well as drug-drug interactions. Decision for use of andexanet alfa is also complicated by its high cost, limited drug availability, and thrombotic risk. This study aimed to describe the utility of anti-Xa DOAC levels as a decision point to administer andexanet alfa.

METHODS

This is a case series of four patients with an anti-Xa DOAC level that received andexanet alfa for oral FXaI reversal in the setting of life-threatening bleeding or prior to procedure.

RESULTS

Four patients were included in the study. Two patients had a known time since last dose of oral FXaI. All patients had a detectable anti-Xa DOAC levels prior to administration of andexanet alfa. Two patients had levels within the peak range, one patient had a level below the peak range, and one patient had a level above the peak range. Andexanet alfa was administered after anti-Xa DOAC level return in all patients.

CONCLUSION

In our case series, obtaining anti-Xa DOAC levels prior to administration of andexanet alfa was achievable and facilitated use of reversal agents in patients with major bleeding or emergent procedural need.

Andexanet alfa and four-factor prothrombin complex concentrate for reversal of apixaban and rivaroxaban in patients diagnosed with intracranial hemorrhage

Limited data exists regarding the clinical outcomes of andexanet alfa and four factor prothrombin complex concentrate (4F-PCC) for reversal of apixaban or rivaroxaban in the setting of intracranial hemorrhage (ICH). The objective of this study was to evaluate clinical outcomes of 4F-PCC and andexanet alfa for reversal of ICH associated with oral factor Xa inhibitors. This was a retrospective, single-center, case series evaluating hemostatic efficacy of patients receiving andexanet alfa) or 4F-PCC for reversal of apixaban or rivaroxaban after ICH. Secondary endpoints included in-hospital mortality, thrombotic complications, timing of reversal agents, intensive care unit and hospital length of stay, patient disposition, and 30-day readmission rate. During the study period, 21 patients received andexanet alfa and 35 received 4F-PCC. Hemostatic efficacy occurred in 64.7% of patients receiving andexanet alfa and 54.8% of receiving 4F-PCC. Thirty-day all-cause mortality was 45.2% for 4F-PCC and 30% for andexanet alfa. Thrombotic events were higher with 4F-PCC (31.4%) compared to andexanet alfa (14.3%). Median time from presentation to administration of reversal agent was 2.67 [1.75-4.13] hours with andexanet alfa and 1.73 [1.21-3.55] hours with 4F-PCC. Discharge to skilled nursing facilities and 30-day readmission were similar between groups. In this cohort, reversal with andexanet alfa and 4F-PCC differed in terms ofhemostatic efficacy and thrombotic events after ICH in patients anticoagulated with apixaban or rivaroxaban.

Meta-Analysis of Reversal Agents for Severe Bleeding Associated With Direct Oral Anticoagulants

BACKGROUND

Direct oral anticoagulants (DOACs) have shown a positive benefit-risk balance in both clinical trials and real-world data, but approximately 2% to 3.5% of patients experience major bleeding annually. Many of these patients require hospitalization, and the administration of reversal agents may be required to control bleeding.

OBJECTIVES

The aim of this study was to investigate clinical outcomes associated with the use of 4-factor prothrombin complex concentrates, idarucizumab, or andexanet for reversal of severe DOAC-associated bleeding.

METHODS

The investigators systematically searched for studies of reversal agents for the treatment of severe bleeding associated with DOAC. Mortality rates, thromboembolic events, and hemostatic efficacy were meta-analyzed using a random effects model.

RESULTS

The investigators evaluated 60 studies in 4,735 patients with severe DOAC-related bleeding who were treated with 4-factor prothrombin complex concentrates (n = 2,688), idarucizumab (n = 1,111), or andexanet (n = 936). The mortality rate was 17.7% (95% confidence interval [CI]: 15.1% to 20.4%), and it was higher in patients with intracranial bleedings (20.2%) than in patients with extracranial hemorrhages (15.4%). The thromboembolism rate was 4.6% (95% CI: 3.3% to 6.0%), being particularly high with andexanet (10.7%; 95% CI: 6.5% to 15.7%). The effective hemostasis rate was 78.5% (95% CI: 75.1% to 81.8%) and was similar regardless of the reversal agent considered. The rebleeding rate was 13.2% (95% CI: 5.5% to 23.1%) and 78% of rebleeds occurred after resumption of anticoagulation. The risk of death was markedly and significantly associated with failure to achieve effective hemostasis (relative risk: 3.63; 95% CI: 2.56 to 5.16). The results were robust regardless of the type of study or the hemostatic scale used.

CONCLUSIONS

The risk of death after severe DOAC-related bleeding remains significant despite a high rate of effective hemostasis with reversal agents. Failure to achieve effective hemostasis strongly correlated with a fatal outcome. Thromboembolism rates are particularly high with andexanet. Comparative clinical trials are needed.

Andexanet Alfa or Prothrombin Complex Concentrate for Factor Xa Inhibitor Reversal in Acute Major Bleeding: A Systematic Review and Meta-Analysis

OBJECTIVES

To combine evidence on andexanet alfa and prothrombin complex concentrates for factor Xa inhibitor-associated bleeding to guide clinicians on reversal strategies.

DATA SOURCES

Embase, Pubmed, Web of Science, and the Cochrane Library.

STUDY SELECTION

Observational studies and randomized clinical trials studying hemostatic effectiveness of andexanet alfa or prothrombin complex concentrate for acute reversal of factor Xa inhibitor-associated hemorrhage.

DATA EXTRACTION

Two independent reviewers extracted the data from the studies. Visualization and comparison of hemostatic effectiveness using Sarode et al or International Society of Thrombosis and Hemostasis Scientific and Standardization Committee criteria at 12 and 24 hours, (venous) thrombotic event rates, and inhospital mortality were performed by constructing Forest plots. Exploratory analysis using a logistic mixed model analysis was performed to identify factors associated with effectiveness and venous thromboembolic event.

DATA SYNTHESIS

A total of 21 studies were included (andexanet: 438 patients; prothrombin complex concentrate: 1,278 patients). The (weighted) mean effectiveness for andexanet alfa was 82% at 12 hours and 71% at 24 hours. The (weighted) mean effectiveness for prothrombin complex concentrate was 88% at 12 hours and 76% at 24 hours. The mean 30-day symptomatic venous thromboembolic event rates were 5.0% for andexanet alfa and 1.9% for prothrombin complex concentrate. The mean 30-day total thrombotic event rates for andexanet alfa and prothrombin complex concentrate were 10.7% and 3.1%, respectively. Mean inhospital mortality was 23.3% for andexanet versus 15.8% for prothrombin complex concentrate. Exploratory analysis controlling for potential confounders did not demonstrate significant differences between both reversal agents.

CONCLUSIONS

Currently, available evidence does not unequivocally support the clinical effectiveness of andexanet alfa or prothrombin complex concentrate to reverse factor Xa inhibitor-associated acute major bleeding, nor does it permit conventional meta-analysis of potential superiority. Neither reversal agent was significantly associated with increased effectiveness or a higher rate of venous thromboembolic event. These results underscore the importance of randomized controlled trials comparing the two reversal agents and may provide guidance in designing institutional guidelines.

Evaluation of oral factor Xa inhibitor-associated extracranial bleeding reversal with andexanet alfa

INTRODUCTION

A reversal agent for factor Xa (FXa) inhibitors, andexanet alfa, was Food and Drug Administration approved without extensive study of clinical effectiveness, due to an overwhelming demand for FXa inhibitor reversal. In this study, we aimed to describe patient selection, clinical effectiveness, and safety of FXa inhibitor reversal with andexanet alfa in patients presenting with extracranial bleeding.

METHODS

Consecutive patients who received andexanet alfa for reversal of FXa inhibitor-associated extracranial hemorrhage were identified. The primary outcome of interest was hemostatic efficacy, assessed using the Sarode et al criteria. Secondary outcomes of interest included incidence of thrombotic episodes post-reversal until discharge and in-hospital mortality.

RESULTS

Twenty-one patients met the inclusion criteria (61.9% male, mean age: 73 years). Anticoagulation reversal with andexanet alfa was deemed effective (excellent [n = 3], good [n = 7]) in 10 (47.6%) patients, and poor in 11 patients (52.4%). Eight (38.1%) patients died, of which three were surgically managed, with all causes of death attributed to hemorrhage. Six ischemic complications occurred in four patients (19.0%); ischemic stroke (n = 2], pulmonary embolism (n = 1), deep vein thrombosis (n = 1), liver ischemia (n = 1), and bowel ischemia (n = 1).

CONCLUSION

We report poor overall outcomes, a low rate of hemostatic effectiveness, and a high rate of ischemic complications and mortality in this retrospective analysis of oral FXa inhibitor reversal with andexanet alfa for extracranial bleeds. More rigorous epidemiological, and ideally randomized studies, are needed to determine the role of andexanet alfa for FXa inhibitor-associated bleeding for extracranial hemorrhages, where large variation in severity and presentation exists.