A meta-analysis of andexanet alfa and prothrombin complex concentrate in the treatment of factor Xa inhibitor-related major bleeding

Anticoagulation reversal (vitamin K, prothrombin complex concentrates, idarucizumab, andexanet-α, protamine)

Bleeding events are common in patients prescribed anticoagulants and can have devastating consequences. Several specific and nonspecific agents have been developed to reverse the effects of anticoagulant drugs or toxins. Vitamin K, as the oldest of these antidotes, specifically counteracts the effects of pharmaceuticals and rodenticides designed to deplete stores of vitamin K-dependent factors. In cases of life-threatening bleeding, the addition of prothrombin complex concentrates (PCCs) allows for the immediate replacement of coagulation factors. While the use of PCCs has been extended to the non-specific reversal of the effects of newer direct oral anticoagulants, the specific agents idarucizumab, targeting dabigatran and andexanet-α, binding factor Xa inhibitors, have recently been developed and are being preferentially recommended by most guidelines. However, despite having rapid effects on correcting coagulopathy, there is to date a lack of robust evidence establishing the clear superiority of direct oral anticoagulant-specific reversal agents over PCCs in terms of haemostatic efficacy, safety or mortality. For andexanet-α, a potential signal of increased thromboembolic risks, comparatively high costs and low availability might also limit its use, even though emerging evidence appears to bolster its role in intracranial haemorrhage. Protamine is the specific agent for the reversal of unfractionated heparin anticoagulation used mainly in cardiovascular surgery. It is much less effective for low molecular weight heparin fragments and is usually reserved for cases with life-threatening bleeding.

Andexanet alfa versus PCC products for factor Xa inhibitor bleeding: A systematic review with meta-analysis

Previous meta-analyses assessed andexanet alfa (AA) or prothrombin complex concentrate (PCC) products for the treatment of Factor Xa inhibitor (FXaI)-associated major bleeding. However, they did not include recent studies or assess the impact of the risk of bias. We conducted a systematic review with meta-analysis on the effectiveness of AA versus PCC products for FXaI-associated major bleeding, inclusive of the studies' risk of bias. PubMed and Embase were searched for comparative studies assessing major bleeding in patients using FXaI who received AA or PCC. We used the Methodological Index for NOn-Randomized Studies (MINORS) checklist and one question from the Joanna Briggs Institute (JBI) Critical Appraisal of Case Series tool to assess the risk of bias. Random-effects meta-analyses were performed to provide a pooled estimate for the effect of AA versus PCC products on hemostatic efficacy, in-hospital mortality, 30-day mortality, and thrombotic events. Low-moderate risk of bias studies were meta-analyzed separately, as well as combined with high risk of bias studies. Eighteen comparative evaluations of AA versus PCC were identified. Twenty-eight percent of the studies (n = 5) had low-moderate risk and 72% (n = 13) had a high risk of bias. Studies with low-moderate risk of bias suggested improvements in hemostatic efficacy [Odds Ratio (OR) 2.72 (95% Confidence Interval (CI): 1.15-6.44); one study], lower in-hospital mortality [OR 0.48 (95% CI: 0.38-0.61); three studies], and reduced 30-day mortality [OR 0.49 (95% CI: 0.30-0.80); two studies] when AA was used versus PCC products. When studies were included regardless of the risk of bias, pooled effects showed improvements in hemostatic efficacy [OR 1.36 (95% CI: 1.01-1.84); 12 studies] and reductions in 30-day mortality [OR 0.53 (95% CI: 0.37-0.76); six studies] for AA versus PCC. The difference in thrombotic events with AA versus PCC was not statistically significant in the low-moderate, high, or combined risk of bias groups. The evidence from low-moderate quality real-world studies suggests that AA is superior to PCC in enhancing hemostatic efficacy and reducing in-hospital and 30-day mortality. When studies are assessed regardless of the risk of bias, the pooled hemostatic efficacy and 30-day mortality risk remain significantly better with AA versus PCC.

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.

Direct oral anticoagulants in trauma patients

PURPOSE OF REVIEW

Direct oral anticoagulants (DOACs) are increasingly prescribed for prevention of thromboembolic events. Thus, trauma care providers are facing a steadily raising number of injured patients on DOACs.

RECENT FINDINGS

Despite a predictable pharmacokinetic profile, the resulting plasma levels of trauma patients upon admission and bleeding risks remain uncertain. Therefore, recent guidelines recommend the measurement of DOAC plasma concentrations in injured patients. Alternatively, DOAC specific visco-elastic tests assays can be applied to identify DOAC patients at bleeding risk.Bleeding complications in trauma patients on DOACs are generally higher compared to nonanticoagulated subjects, but comparable to vitamin K antagonists (VKAs). In particular, a traumatic brain injury does not carry an increased risk of intracranial bleeding due to a DOAK intake compared to VKAs. Current studies demonstrated that up to 14% of patients with a hip fracture are on DOACs prior to surgery. However, the majority can be operated safely within a 24h time window without an increased bleeding rate.Specific antagonists facilitate rapid reversal of patients on DOACs. Idarucizumab for dabigatran, and andexanet alfa for apixaban and rivaroxaban have been approved for life threatening bleeding. Alternatively, prothrombin complex concentrate can be used. Dialysis is a potential treatment option for dabigatran and haemoabsorption with special filters can be applied in patients on FXa-inhibitors.

SUMMARY

Current guidelines recommend the measurement of DOAC plasma levels in trauma patients. Compared to VKAs, DOACs do not carry a higher bleeding risk. DOAC specific antagonists facilitate the individual bleeding management.

Use of Andexanet Alfa for Factor Xa Inhibitor Reversal in US Verified Trauma Centers: A National Survey

Direct oral factor Xa inhibitors are replacing vitamin K-dependent antagonists as anticoagulation treatment in many clinical scenarios. Trauma centers are noting an increase in patients presenting on these medications. The 2018 Food and Drug Administration approval of andexanet alfa provides an alternative anticoagulation reversal. Barriers may limit utilization of new medications including a lack of grade 1A evidence supporting the use of prothrombin complex concentrate (PCC) versus andexanet alfa and cost. To evaluate barriers of andexanet alfa utilization by trauma surgeons, a 15-question survey was conducted. There was a 9% completion rate (n = 89). The results revealed 23.5% would choose andexanet alfa as first-line treatment in children, and 25.8% as first-line treatment in adults. The majority of respondents, 64.7% and 67.4%, would use PCC preferentially in children and adults, respectively. Respondents indicated that cost burden was an overriding factor (76.3%); 42.4% cited lack of high-level efficacy data of andexanet alfa for reversal of factor Xa inhibitors. Additional double-blinded multi-institutional randomized controlled trials comparing 4F-PCC and andexanet alfa for factor Xa inhibitor reversal are needed to support efficacy especially with the increased cost associated.

Lower mortality with andexanet alfa vs 4-factor prothrombin complex concentrate for factor Xa inhibitor-related major bleeding in a U.S. hospital-based observational study

Background

Well-designed studies with sufficient sample size comparing andexanet alfa vs 4-factor prothrombin complex concentrate (4F-PCC) in routine clinical practice to evaluate clinical outcomes are limited.

Objectives

To compare in-hospital mortality in patients hospitalized with rivaroxaban- or apixaban-related major bleeding who were treated with andexanet alfa or 4F-PCC.

Methods

An observational cohort study (ClinicalTrials.gov identifier: NCT05548777) was conducted using electronic health records between May 2018 and September 2022 from 354 U.S. hospitals. Inclusion criteria were age ≥18 years, inpatient admission with diagnosis code D68.32 (bleeding due to extrinsic anticoagulation), a record of use of the factor Xa inhibitors rivaroxaban or apixaban, andexanet alfa or 4F-PCC treatment during index hospitalization, and a documented discharge disposition. Multivariable logistic regression on in-hospital mortality with andexanet alfa vs 4F-PCC was performed. The robustness of the results was assessed via a supportive propensity score-weighted logistic regression.

Results

The analysis included 4395 patients (andexanet alfa, n = 2122; 4F-PCC, n = 2273). There were 1328 patients with intracranial hemorrhage (ICH), 2567 with gastrointestinal (GI) bleeds, and 500 with critical compartment or other bleed types. In the multivariable analysis, odds of in-hospital mortality were 50% lower for andexanet alfa vs 4F-PCC (odds ratio [OR], 0.50; 95% CI, 0.39-0.65; P < .01) and were consistent for both ICH (OR, 0.55; [0.39-0.76]; P < .01) and GI bleeds (OR, 0.49 [0.29-0.81]; P = .01). Similar results were obtained from the supporting propensity score-weighted logistic regression analyses.

Conclusion

In this large observational study, treatment with andexanet alfa in patients hospitalized with rivaroxaban- or apixaban-related major bleeds was associated with 50% lower odds of in-hospital mortality than 4F-PCC. The magnitude of the risk reduction was similar in ICH and GI bleeds.

Andexanet Alfa to Reverse the Effect of Factor Xa Inhibitors in Intracranial Hemorrhage

Andexanet alfa (AA) is a recombinant factor Xa competing for binding with factor Xa inhibitors, thereby reversing their anticoagulation effects. Since 2019, it has been approved for individuals under apixaban or rivaroxaban therapy suffering from life-threatening or uncontrolled bleeding. Apart from the pivotal trial, real-world data on the use of AA in daily clinics are scarce. We reviewed the current literature on patients with intracranial hemorrhage (ICH) and summarized the available evidence regarding several outcome parameters. On the basis of this evidence, we provide a standard operating procedure (SOP) for routine AA application. We searched PubMed and additional databases through 18 January 2023 for case reports, case series, studies, reviews, and guidelines. Data on hemostatic efficacy, in-hospital mortality, and thrombotic events were pooled and compared with the pivotal trial data. While hemostatic efficacy in world-wide clinical routine seems to be comparable to the pivotal trial, thrombotic events and in-hospital mortality appear to be substantially higher. Various confounding factors responsible for this finding such as exclusion and inclusion criteria resulting in a highly selected patient cohort within the controlled clinical trial have to be considered. The SOP provided should support physicians in patient selection for AA treatment as well as facilitate routine use and dosing. This review underlines the urgent need for more data from randomized trials to appreciate the benefit and safety profile of AA. Meanwhile, this SOP should help to improve frequency and quality of AA use in patients suffering from ICH while on apixaban or rivaroxaban treatment.

In vitro reversal of direct factor Xa inhibitors: Direct comparison of andexanet alfa and prothrombin complex concentrates Cofact and Beriplex/Kcentra

Background

Both andexanet alfa and four‐factor prothrombin complex concentrate (4F‐PCC) are clinically applied reversal agents for direct factor Xa inhibitors (FXaIs) in emergency situations. Controversy exists whether 4F‐PCC is as effective as andexanet alfa in correcting FXaI anticoagulation.

Objective

This in vitro study was designed to directly compare andexanet alfa with two different 4F‐PCCs (Cofact and Beriplex/Kcentra) in their ability to correct FXaI anticoagulation.

Method

Normal plasma was spiked with apixaban or rivaroxaban. Reversal of anticoagulation was assessed using a thrombin generation assay and a fibrin generation–clot lysis test.

Results

Andexanet alfa, applied at clinically recommended doses, was effective in restoring thrombin generation as evidenced by correction of thrombin generation lag time, peak thrombin, and endogenous thrombin potential (ETP). Clotting time and clot resistance to fibrinolytic breakdown was corrected over the full range of applied FXaI (0–800 ng/ml). 4F‐PCC in increasing doses (0.625, 1.25 and 2 IU/ml; approximately 25, 50, and 80 IU/kg) only partially restored thrombin generation lag time and clotting time. Partial correction to overnormalization of peak thrombin and ETP was observed, depending on FXaI concentration and PCC dose. Clot resistance to fibrinolytic breakdown was dose‐dependently improved to above normal. Beriplex/Kcentra was consistently less effective than Cofact.

Conclusion

Both andexanet alfa and 4F‐PCC improved coagulation that is hampered by FXaIs. While andexanet alfa corrected all thrombin generation parameters, 4F‐PCC predominantly increased peak thrombin and ETP. Especially heparin‐free 4F‐PCC also improved clot stability against fibrinolytic breakdown. Beriplex/Kcentra contains heparin, and this may have caused reduced effectivity compared to Cofact.

Antithrombotic drug removal from whole blood using Haemoadsorption with a porous polymer bead sorbent

AIM

To evaluate the ability of the DrugSorb™-AntiThrombotic Removal (ATR) haemoadsorption device utilizing porous polymer bead sorbent technology to remove three commonly used antithrombotic drugs from whole blood.

METHODS AND RESULTS

We evaluated the removal of apixaban, rivaroxaban, and ticagrelor by the DrugSorb-ATR haemoadsorption device in a benchtop clinical scale model using bovine whole blood. Blood spiked at clinically relevant concentrations of an antithrombotic agent was continuously circulated through a 300-mL DrugSorb-ATR haemoadsorption device at a flow rate of 300 mL/min. Drug concentration was monitored over 6 h to evaluate drug removal. Results were compared with a control circuit without the haemoadsorption device. Removal rates at 30, 60, 120, and 360 minutes were: apixaban: 81.5%, 96.3%, 99.3% >99.8%; rivaroxaban: 80.7%, 95.1%, 98.9%, >99.5%; ticagrelor: 62.5%; 75%, 86.6%, >95% (all P <0.0001 vs. control). Blood pH and haematological parameters were not significantly affected by the DrugSorb-ATR haemoadsorption device when compared with the control circuit.

CONCLUSION

DrugSorb-ATR efficiently removes apixaban, rivaroxaban, and ticagrelor in a clinical-scale benchtop recirculation circuit with the bulk of removal occurring in the first 60 minutes. The clinical implications of these findings are currently investigated in patients undergoing on-pump cardiothoracic surgery in two US pivotal trials (ClinicalTrials.gov Identifiers: NCT04976530 and NCT05093504).

Andexanet Alfa Versus Prothrombin Complex Concentrates/Blood Products as Apixaban/Rivaroxaban Reversal Agents: A Survey Among Pediatric Hematologists

Direct oral factor Xa inhibitors (DXIs) are approved for use in adult patients with non-valvular heart disease for stroke prevention, and the treatment/prevention of venous thromboembolism (VTE). Recent pediatric clinical trials have demonstrated safety and efficacy of direct oral anticoagulants (DOACs) in the treatment of VTE. However, there is a lack of evidence regarding the use of andexanet alfa and prothrombin complex concentrates (PCC) for anticoagulation reversal of DXIs in the pediatric population. To better understand current DXI reversal strategies in this age group, a 10-question survey was conducted among pediatric hematology members of the Hemostasis and Thrombosis Research Society. Seventeen percent completed the survey (27 of 163 pediatric hematology members) with 74% (n = 20) reporting their use of DXIs for the treatment and prevention of VTE. Forty-four percent (n = 12) would choose andexanet alfa as first-line treatment for life-threatening bleeding while 52% (n = 14) would use PCC first with one individual choosing recombinant factor VII for DXI reversal. Clinical studies of andexanet alfa and PCC for the management of DXI-associated life-threatening bleeding require further investigation in the pediatric population.

Management of Coagulopathy in Bleeding Patients

Early recognition of coagulopathy is necessary for its prompt correction and successful management. Novel approaches, such as point-of-care testing (POC) and administration of coagulation factor concentrates (CFCs), aim to tailor the haemostatic therapy to each patient and thus reduce the risks of over- or under-transfusion. CFCs are an effective alternative to ratio-based transfusion therapies for the correction of different types of coagulopathies. In case of major bleeding or urgent surgery in patients treated with vitamin K antagonist anticoagulants, prothrombin complex concentrate (PCC) can effectively reverse the effects of the anticoagulant drug. Evidence for PCC effectiveness in the treatment of direct oral anticoagulants-associated bleeding is also increasing and PCC is recommended in guidelines as an alternative to specific reversal agents. In trauma-induced coagulopathy, fibrinogen concentrate is the preferred first-line treatment for hypofibrinogenaemia. Goal-directed coagulation management algorithms based on POC results provide guidance on how to adjust the treatment to the needs of the patient. When POC is not available, concentrate-based management can be guided by other parameters, such as blood gas analysis, thus providing an important alternative. Overall, tailored haemostatic therapies offer a more targeted approach to increase the concentration of coagulation factors in bleeding patients than traditional transfusion protocols.

Prothrombin complex concentrates for the urgent reversal of apixaban and rivaroxaban - an Australian retrospective cohort study

BACKGROUND

Direct acting oral anticoagulants (DOACs) are now commonly prescribed medications. Urgent reversal of their anticoagulant effect is sometimes required in emergency situations. In Australia, a specific reversal agent for factor Xa (FXa)- inhibitor DOACs is not available. Instead, two non-specific haemostatic agents, activated prothrombin complex concentrate (aPCC) and 3 factor-prothrombin complex concentrate (3F-PCC), are used off-label despite a paucity of evidence for their effectiveness or safety.

METHODS

We conducted a single-centre retrospective cohort study to investigate the use of aPCC and 3F-PCC for patients on FXa-inhibitor DOACs who present with a significant bleeding event or who require urgent surgery. The primary outcome was haemostatic efficacy according to prespecified criteria. Safety outcomes included the thromboembolic event rate and all-cause mortality during the hospital admission.

RESULTS

A total of 51 patients were included in the study (36 patients who had a spontaneous bleeding even (SBE) and 15 non-bleeding patients who required urgent perioperative management). Thirty-one patients received aPCC and 20 patients received 3F-PCC. Haemostasis was adjudicated as effective in all assessable patients (n = 50; 100%). Thromboembolic events occurred in three patients who received aPCC and one patient who received 3F-PCC. All-cause mortality was 7.8% (4 patients).

CONCLUSIONS

Both aPCC and 3F-PCC are useful adjuncts for the management of patients who require urgent reversal of the anticoagulant effect of FXa-inhibitor DOACs. However, the risk of thromboembolism in this patient group requires careful consideration. Prospective, comparator studies are needed along with the development of guidelines that reflect the availability of haemostatic agents in Australia. This article is protected by copyright. All rights reserved.