The reversal effect of prothrombin complex concentrate (PCC), activated PCC and recombinant activated factor VII in apixaban-treated patients in vitro

Twenty years of the four-factor prothrombin complex concentrate Octaplex/Balfaxar: A narrative review

Prothrombin complex concentrate (PCC) is used to boost thrombin potential, support clot formation, and aid in the treatment and prophylaxis of bleeding. The two main forms of PCC are three-factor (3 F-PCC; comprising coagulation factors II, IX, and X) and four-factor (4F-PCC; factors II, VII, IX, X), which contain 25 times the clotting factors found in human plasma. This narrative review summarizes published efficacy and safety data on one 4F-PCC (Octaplex/Balfaxar, Octapharma) within its recognized uses and explores potential applications across different clinical contexts. Clinically available for > 20 years, Octaplex/Balfaxar is supplied as a freeze-dried powder for reconstitution and intravenous infusion. This 4F-PCC contains non-activated forms of coagulation factors as well as anticoagulant proteins C and S, potentially affording a balanced hemostatic effect and mitigating thrombosis risk. Production involves two virus inactivation/removal steps: solvent/detergent treatment and nanofiltration. 4F-PCC is approved for acquired deficiency of vitamin K-dependent clotting factors, such as those induced by vitamin K antagonists (VKAs, e.g., warfarin), and for congenital deficiency of factors II and X. Five published trials in 444 adult patients demonstrated the efficacy of 4F-PCC in VKA reversal, reducing the international normalized ratio (INR) with only two potentially treatment-related thrombotic events reported. While 4F-PCC dosing is currently indicated to be INR-guided, emerging evidence supports fixed dosing as an alternative to conventional weight-based dosing for VKA reversal. Recent guidelines support 4F-PCC use for direct oral anticoagulant-associated bleeding, cardiac surgery and trauma/emergencies. Ongoing studies will further clarify the efficacy and safety of 4F-PCC beyond its approved indications.

Reversal of pre-injury factor-Xa inhibitors with prothrombin complex concentrates in patients following traumatic brain injury

INTRODUCTION

There is substantial debate on the best method to reverse factor Xa-inhibitors in patients following traumatic brain injury (TBI). Prothrombin complex concentrates (PCC) have been used for this indication but their role has been questioned. This study reported failure rates with PCC in patients following TBI and as a secondary objective, compared 4-factor (4 F-PCC) and activated PCC (APCC).

MATERIAL AND METHODS

Consecutive patients with TBI on factor Xa-inhibitors admitted to one of two trauma centers were retrospectively identified. Patients with penetrating TBI, delays in PCC administration (>6 h), receipt of tranexamic acid, factor VIIa or no follow up CT-scan were excluded. The primary outcome was treatment failure defined as hematoma expansion > 20% from baseline for SDH, EDH or IPH, a new hematoma not present on the initial CT scan or any expansion of a SAH or IVH. Hematoma expansion was further categorized as symptomatic or asymptomatic, designated by a change in the motor GCS score, neurologic exam or change ≥ 3 in NIH Stroke Scale. Multi-variate analysis was performed.

RESULTS

There were 43 patients with a mean age of 77 ± 13 years with primarily mild TBI (95%) after a ground level fall (79%). The mean dose was 41 ± 12 units/kg. Sixty percent received 4 F-PCC and 40% APCC. The incidence of treatment failure was 28% (12/43). Of the 12 patients with hematoma expansion, only 3 were symptomatic (9.3%). Hematoma expansion with 4 F-PCC and APCC were similar (27% vs. 29%,p = .859). Only sex was associated with hematoma expansion on multivariate analysis [OR (95% CI) = 6.7 (1.1 - 40.9)].

CONCLUSION

PCC was an effective option for factor Xa inhibitor reversal following TBI. The relationship between radiographic expansion and clinical expansion was poor.

Administration of andexanet alfa for traumatic intracranial hemorrhage in the setting of massive apixaban overdose: A case report

PURPOSE

Apixaban is a direct-acting oral anticoagulant that selectively inhibits factor Xa. Reversal strategies utilized to treat factor Xa inhibitor-associated bleeding include andexanet alfa, prothrombin complex -concentrate (PCC), and activated PCC (aPCC). The optimal treatment of traumatic intracranial hemorrhage in the setting of an apixaban overdose is unknown.

SUMMARY

This case report describes a 69-year-old female who initially presented to an emergency department at a community hospital due to a ground-level fall with traumatic intracranial hemorrhage. The patient reportedly ingested apixaban 275 mg, carvedilol 250 mg, atorvastatin 1,200 mg, and unknown amounts of amlodipine and ethanol. Anti-inhibitor coagulant complex, an aPCC, was administered approximately 3 hours after presentation. Initial thromboelastography performed approximately 4 hours after presentation showed a prolonged reaction time of 16.8 minutes. Ongoing imaging and evidence of coagulopathy prompted repeated aPCC administration to a cumulative dose of approximately 100 U/kg. The patient underwent craniotomy with hematoma evacuation. Postoperative imaging showed expansion of the existing intracranial hemorrhage and new areas of hemorrhage. Andexanet alfa was administered approximately 18 hours after presentation, followed by repeat craniotomy with evacuation of the hematoma. No further expansion of the intracranial hemorrhage was observed, and the reaction time on thromboelastography was normalized at 6.3 minutes.

CONCLUSION

This case suggests that andexanet alfa may have a role in the management of traumatic hemorrhage in the setting of an acute massive apixaban overdose. Use of andexanet alfa, PCC, and aPCC in this context requires further research.

DOAC-associated bleeding, hemostatic strategies, and thrombin generation assays - a review of the literature

Direct oral anticoagulants (DOACs) account for most oral anticoagulant use. DOAC-associated bleeding events are commonly encountered in clinical practice and are associated with substantial morbidity and mortality. Both specific reversal agents and nonspecific hemostatic therapies, such as prothrombin complex concentrates, are used in the management of DOAC-associated bleeding. Measuring hemostatic efficacy and demonstrating a clinical impact from these therapies among studies of bleeding patients is challenging. Thrombin generation assays provide information on the total hemostatic potential of plasma, and have emerged as a promising modality to both measure the impact of DOACs on coagulation and to evaluate the effects of hemostatic therapies among patients with DOAC-associated bleeding. The mechanisms by which nonspecific hemostatic agents impact coagulation and thrombin generation in the context of DOAC therapy are unclear. As a result, we undertook a review of the literature using a systematic search strategy with the goal of summarizing the effects of DOACs on thrombin generation and the effects of both specific reversal agents and nonspecific hemostatic therapies on DOAC-altered thrombin generation parameters. We sought to identify clinical studies focusing on whether altered thrombin generation is associated with clinical bleeding and whether correction of altered thrombin generation parameters predicts improvements in clinical hemostasis. Lastly, we sought to outline future directions for the application of thrombin generation assays toward anticoagulation therapies and the question of anticoagulation reversal.

In Vitro Apixaban Removal By CytoSorb Whole Blood Adsorber: An Experimental Study

OBJECTIVES

The use of unopposed oral anticoagulants while undergoing cardiothoracic surgery is associated with severe bleeding and increased morbidity. The aim of this experimental study was to examine if the apixaban concentration in reconstituted blood could be reduced in an in vitro setup by the use of CytoSorb whole blood adsorber, and to study how this affected global coagulation assays.

DESIGN AND SETTING

An experimental study performed in a laboratory.

PARTICIPANTS

An in vitro setup with reconstituted whole blood.

INTERVENTIONS

Reconstituted whole blood spiked with apixaban circulated in an in vitro circuit with the CytoSorb 300 mL device connected.

MEASUREMENTS AND MAIN RESULTS

Blood samples were drawn at 0, 5, 15, 30, 60, and 120 minutes of adsorption. The apixaban concentration was measured at each time point. In addition, the global coagulation assays, thromboelastometry clotting time and thrombin generation, were performed, and the results were compared with baseline values obtained before spiking blood with apixaban. After 30 minutes of adsorption, the mean apixaban concentration was reduced from 414.3 (±69.1) ng/mL to 33 (±11.4) ng/mL. Thrombin generation showed maximum effect after 60 minutes, and the thromboelastometry clotting time was close to baseline values after 120 minutes.

CONCLUSIONS

In this in vitro study, apixaban concentrations were effectively reduced, and the clotting time and thrombin generation assays were normalized by the use of CytoSorb whole blood adsorber.

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.

Investigation of the Optimal Dose aPCC in Reversing the Effect of Factor Xa Inhibitors-An In Vitro Study

Factor (F) Xa inhibitors are safe and effective alternatives to warfarin. There are concerns about the lack of a reversal strategy in case of serious bleeds or need for emergency surgery in situations when the antidote andexanet alfa is not available. Factor concentrates are widely used, but there are few clinical studies regarding the reversal effect of activated prothrombin complex concentrate (aPCC). Because of the feared thrombogenicity, administration of the lowest effective dose would be desirable. To determine the lowest concentration of aPCC sufficient to reverse the effect of rivaroxaban and apixaban. Blood from 18 healthy volunteers were supplemented with apixaban or rivaroxaban. aPCC was added to obtain 10 different concentrations ranging from 0.08-1.60 U/mL. Thromboelastometry and thrombin generation assay were used to assess the reversal effect. aPCC concentrations of 0.08 and 0.16 U/mL restored thromboelastometry clotting time to baseline in apixaban (P = 1.0) and rivaroxaban (P = 1.0)-containing samples, respectively. The concentrations 0.08 U/mL (P = 0.5) and 0.24 U/mL (P = 0.2) were sufficient to restore thrombin generation. Concentrations of 0.56 U/mL and higher, caused significantly higher ETP than baseline in apixaban-containing samples (P < 0.05). aPCC concentrations lower than previously reported were effective in reversing the effect of FXa inhibitors in vitro.

Factor VIII Inhibitor Bypassing Activity (FEIBA) Reversal for Apixaban and Rivaroxaban in Patients With Acute Intracranial and Nonintracranial Hemorrhage

BACKGROUND

The clinical use of factor VIII inhibitor bypassing activity (FEIBA) for factor Xa (FXa) inhibitor reversal is derived from small studies with notable variation in patient eligibility for use, dosage regimens, concurrent supportive care, and outcome measures. Consequently, additional effectiveness and safety data are warranted to expand the literature evaluating FEIBA for FXa inhibitor reversal.

OBJECTIVE

This study sought to determine the incidence of observed effective hemostasis within 24 hours of post-FEIBA® administration as well as in-hospital and 30-day post-discharge incidences of thromboembolic event (TEE) and mortality between apixaban and rivaroxaban in the intracranial hemorrhage (ICH) and non-ICH populations.

METHODS

This case series evaluated patients between January 1, 2014 through July 1, 2019 who received at least one FEIBA® dose for apixaban or rivaroxaban reversal secondary to acute ICH or non-ICH. Patient demographics, FEIBA® dosages, adjunct treatments, effectiveness, and safety outcomes were retrospectively collected from electronic medical record review. Modified hemostasis outcomes, adapted from criteria previously published by Sarode et al., TEE, and mortality between apixaban and rivaroxaban in the ICH and non-ICH populations were evaluated.

RESULTS

Among the 104 patients evaluated, 62 received apixaban and 42 rivaroxaban. Thirty apixaban and 25 rivaroxaban users experienced ICH, whereas 32 apixaban and 17 rivaroxaban users experienced non-ICH. Among the combined ICH and non-ICH populations, effective hemostasis occurred in 89%, TEE in 8%, and mortality in 13%. No statistically significant differences were observed within ICH and non-ICH populations receiving apixaban or rivaroxaban regarding effective hemostasis, TEE, or mortality.

CONCLUSION AND RELEVANCE

The combined ICH and non-ICH overall rates of effective hemostasis, TEE, and mortality were comparable to preexisting studies of FEIBA for factor Xa inhibitor reversal. The limitations inherent to the study design warrant a randomized controlled trial with an active comparator to confirm these observations.

Andexanet versus prothrombin complex concentrates: Differences in reversal of factor Xa inhibitors in in vitro thrombin generation

BACKGROUND

Andexanet alfa (andexanet) is a modified human factor Xa (FXa) approved for anticoagulation reversal in patients with life-threatening bleeding treated with rivaroxaban or apixaban. Four-factor prothrombin complex concentrates (4F-PCCs) are approved for reversal of vitamin K antagonist-induced anticoagulation but not FXa inhibitors. The mechanism and effectiveness of 4F-PCCs for FXa inhibitor reversal are unclear.

OBJECTIVE

To investigate the mechanism and impact of 4F-PCCs on reversal of rivaroxaban and apixaban in vitro compared to andexanet.

METHODS

The effect of 4F-PCCs (or individual factors) on tissue factor-initiated thrombin generation (TF-TG) was evaluated in human plasma, with or without rivaroxaban or apixaban, and compared with andexanet under the same conditions.

RESULTS

In the TF-TG assay, 4F-PCC completely reversed warfarin anticoagulation. Andexanet normalized TF-TG over a wide range of apixaban and rivaroxaban concentrations tested (19-2000 ng/mL). However, 4F-PCC (or individual factors) was unable to normalize endogenous thrombin potential (ETP) or peak thrombin (Peak) in the presence of apixaban or rivaroxaban (75-500 ng/mL). TF-TG was only normalized by 4F-PCC at inhibitor concentrations <75 ng/mL (ETP) or <37.5 ng/mL (Peak). These data can be explained by the estimated thresholds of FXa activity required to support normal TF-TG based on the inhibitor:FXa ratios and levels of uninhibited FXa. The data are consistent with healthy volunteer studies where TF-TG is not normalized until inhibitor levels are substantially decreased.

CONCLUSIONS

Both the theoretical calculations and experimental data demonstrated that 4F-PCCs are only able to normalize TG over a low and narrow range of FXa inhibitor concentrations (<75 ng/mL).

Current status of oral anticoagulant reversal strategies: a review

Utilization of direct oral anticoagulants (DOAC) have steadily increased since their approval and are now recommended over warfarin for both stroke prevention in nonvalvular atrial fibrillation and treatment of venous thromboembolism (VTE). With increased DOAC use, the number of major bleeding events requiring medical intervention will continue to rise. Until 2015, warfarin maintained an advantage as the only oral anticoagulant with a specific reversal agent. Since then, idarucizumab has been approved for dabigatran reversal and recently, andexanet alfa was granted approval for the reversal of apixaban or rivaroxaban in patients with life-threatening or uncontrolled bleeding events. Due to the manufacturing practices required to yield these reversal therapies, they are available at high cost to hospital systems and as a result, have been met with resistance. Data exists describing both prothrombin complex concentrates (PCC) and andexanet alfa for DOAC reversal, however, without head-to-head comparison. Until future studies are available, current literature must be critically evaluated to aid in the clinical decision-making process of how to treat patients with life-threatening DOAC-related bleeding.

A Low-Dose 4F-PCC Protocol for DOAC-Associated Intracranial Hemorrhage

Purpose:

Current guidelines favor 4F-PCC over plasma for reversal of warfarin. Uncertainty remains on the hemostatic effectiveness and thrombotic risk of 4F-PCC for direct-acting oral anticoagulants (DOACs), particularly in patients with intracranial hemorrhage (ICH). This study sought to evaluate the effectiveness and safety of a lower dose protocol of 25 units/kg 4F-PCC for the management of DOAC-associated ICH in a real-world setting.

Materials and Methods:

This was a retrospective study of adult patients who received at least one dose of 4F-PCC from March 2014 to December 2015 for DOAC-associated ICH. The primary outcome was hemostatic effectiveness within 24 hours. The secondary outcome was thromboembolic events within 14 days.

Results:

Twenty-two patients received 4F-PCC for DOAC-associated ICH and were included in the analysis. Hemostasis was evaluable in 19 patients with post-4F-PCC imaging available and occurred in 18/19 (94.7%) patients. Thromboembolism occurred in 2 out of 22 patients (9.1%).

Conclusions:

The use of a lower dose protocol of 25 units/kg of 4F-PCC resulted in high rates of hemostasis in patients with DOAC-associated ICH. Two patients developed thrombotic events within 14 days of 4F-PCC administration.