Dose Of Apixaban Research Articles

Complication comparison in intermediate-to-high risk venous thromboembolism patients, treated with high vs standard dose apixaban and rivaroxaban after low molecular weight heparin

Abstract Background In patients with intermediate-to-high risk venous thromboembolism (VTE), current guidelines recommend initial treatment with low molecular weight heparin (LMWH), followed by an oral anticoagulant. However, the studies supporting these guidelines have only focused on the use of Edoxaban and Dabigatran after 5 days of LMWH treatment. To date there are no studies supporting similarly implemented guidelines for Apixaban and Rivaroxaban. Purpose To investigate the incidence of bleeding complications and thrombosis in intermediate-to-high risk VTE patients, when treated with either lead-in high or standard dose Rivaroxaban or Apixaban, following initial LMWH treatment. Methods Through a real-life retrospective study of 844 intermediate-to-high risk VTE patients, 584 were initially treated with LMWH and subsequently Apixaban or Rivaroxaban and divided into two groups. The first group of 514 patients, received high dose Apixaban or Rivaroxaban (10mg x 2 for 7 days and 15mg x 2 for 21 days respectively) before being reduced to their standard doses. The remaining 70 patients, instead transitioned directly to the standard doses (5mg x 2 and 20mg x 1 respectively) from LMWH. All patients started treatment between 2018 and 2023, and all complications were recorded until one year following initiation of treatment. Treatment complications include recurrent VTE, separated into deep vein thrombosis and pulmonary embolism, and bleeding complications in the form of fatal, non-fatal, minor and a drop in haemoglobin. The recurrence of VTE and incidence of bleeding complications were evaluated as the primary efficacy outcome and safety outcome respectively. Results Overall, 4.7% of patients treated with initial high dose Apixaban or Rivaroxaban suffered major bleeding complications as opposed to 2.9% treated with the standard dose (p=<0.05). Out of all complications, 5 were fatal, all of which were part of the high dose group and included 3 cerebral and 2 gastrointestinal bleeds. However, minor bleeding complications were more frequent in the standard dose group, presenting in 26.1% of patients, while, paradoxically, the high dose group had similar complications in only 15.8% of patients (p=<0.05). Although treated with a higher dose, 6/478 (1,26%) incurred a recurrent thrombus within a year of treatment, while the standard dose group had no cases of recurrence, though this was not a statistically significant result. Conclusion Directly transitioning from LMWH to standard dose Apixaban/Rivaroxaban in intermediate-to-high risk VTE, leads to a statistically significant reduced incidence of major bleeding complications, without an increased risk of recurrent thrombosis.

Impact of real-world off-label dose of Apixaban on long-term clinical outcomes in patients with atrial fibrillation and chronic kidney disease

Abstract Background Apixaban represent one of the cornerstone treatments to prevent cardioembolic events in patients with nonvalvular atrial fibrillation (NVAF). However, the choices of Apixaban dose guided by the decision-making process of the physician, which considers specific according to kidney functions are inconsistent in the real-world practice. Objective The objective of the present study is to evaluate the effects of real-world Off-label dose of Apixaban on long-term clinical outcomes in NVAF patients with chronic kidney disease (CKD). Methods Our database of AF patients diagnosed with CKD from 2018 to 2023 was used to obtain laboratory, echocardiography, electrocardiogram (ECG), and clinical outcomes data. Inclusion criteria were all AF patients with CKD using Apixaban. And we compared bleeding, systemic thrombotic events including stroke/systemic embolism and death according to off-label real -world dose of Apixaban. Results Among 635 patients with AF and CKD (76.9±10.4 years), 335 (52.8%) patients took off-label underdosed Apixaban. Difference in the baseline characteristics was not observed among patients including CHA2DS2 VASc score and HASBLED score. During the median 18-month follow-up, a lower incidence of bleeding events (P=0.001) was observed in the off-label underdosed Apixaban group compared to those with standard dose or off-label overdosed Apixaban. However, there was no significant difference of systemic thrombotic events including stroke/systemic embolism and death according to off-label real-world dose of Apixaban (off-label underdose vs. standard dose, P=1.000; off-label overdose vs. standard dose, P=1.000; off-label underdose vs. off-label overdose, P=0.609). In multivariate analysis, HASBLED score was independent risk factors for bleeding events (OR 9.650; CI 1.998-46.622; P=0.005). Conclusions Compared with standard or off-label overdose of Apixaban, off-label underdose of Apixaban was associated with a lower risk of bleeding in patients with AF and CKD, with no difference in the risk of stroke/systemic embolism or death, supporting the apixaban dosing tailored to specific clinical features and drug pharmacokinetics of the Asian patients.

Plasma apixaban levels and thrombin generation assay in patients with atrial fibrillation with dose reduction criteria of apixaban

Abstract Background Off-label reduced-dose apixaban is commonly prescribed in patients with atrial fibrillation (AF). However, the pharmacokinetic data of apixaban according to the dosage and label is limited especially in those with dose reduction criteria of apixaban. Purpose We investigated the apixaban plasma concentration (PC) and thrombin generation assay (TGA) parameters across different apixaban dose settings. Methods We enrolled 398 non-valvular AF patients with more than single-dose reduction criteria of apixaban and divided them into three groups: (1) on-label standard dose (single dose-reduction criterion with standard-dose of apixaban 5mg twice daily, n=173); (2) off-label reduced-dose (single dose-reduction criterion with apixaban 2.5mg twice daily, n=61); and (3) on-label reduced-dose (two or more dose-reduction criteria with apixaban 2.5mg twice daily, n=164). Apixaban PC by anti-Xa assay and TGA parameters of these three groups were compared at the trough level. Results The on-label standard dose group showed a higher PC than the on-label reduced dose (124.7 vs. 80.3 ng/mL, p<0.001), and the on-label reduced dose exhibited a higher PC than the off-label reduced dose (80.3 vs. 53.2 ng/mL, p=0.031) (Figure). The TGA parameters displayed a similar pattern of differences, with the on-label standard dose group tends to show the least thrombogenic profiles (Figure). Lower creatinine clearance (CrCl), older age, and female sex were statistically significant predictors for a higher apixaban PC by multivariable regression model (p<0.001, p=0.043, and 0.023, respectively), and CrCl was the most influential variable to dichotomize apixaban PC in all three groups (Figure). Conclusions Off-label reduced-dose apixaban group exhibited significantly lower apixaban level than both on-label standard dose and on-label reduced-dose apixaban groups, suggesting the importance of adhering to current dose-reduction criteria for maintaining appropriate apixaban levels. Caution is particularly advised in off-label under-dosing for patients with high creatinine clearance. Further investigation into the impact of off-label under-dosing on clinical outcomes is essential to guide optimal therapeutic strategies.

Efficacy and Safety of Rivaroxaban, Apixaban, and Edoxaban for Nonvalvular Atrial Fibrillation Based on Blood Coagulation Activity and Drug Plasma Concentration: SETtsu and North Osaka Multicenter Direct Oral AntiCoagulant (SET DOAC) Registry

Background: The therapeutic effects of oral anticoagulant drugs for nonvalvular atrial fibrillation (NVAF) suggest that the three factor Xa (FXa) inhibitors may have distinct safety profiles, though this is not yet fully conclusive. This study investigated the current dosing of rivaroxaban, apixaban, and edoxaban by monitoring drug plasma concentration (PC) and coagulation activity from the viewpoint of the safety. Methods and results: This multicenter clinical study monitored the drug PC and two coagulation biomarkers (fibrinogen and fibrin monomer complex [FMC]) at peak and trough timing in 268 outpatients taking rivaroxaban (n = 72), apixaban (n = 71), and edoxaban (n = 125) for NVAF. Doses were adjusted based on the dose-adjustment criteria of each drug. Referencing our previous study, peak drug PC remained below the cut-off level for predicting bleeding events except in eight patients (rivaroxaban, n = 3; apixaban, n = 2; edoxaban, n = 3) in whom bleeding events occurred. Among them, two (one each on rivaroxaban and edoxaban) had a peak drug PC below the cut-off level. Drug PCs widely varied from peak to trough, whereas FMC levels, reflecting thrombin activity, remained within the normal range (<6.1 µg/mL) regardless of PC variations. These results indicated that the anticoagulant effects of these drugs persisted throughout the day regardless of the drug PC levels, dosage, and dosing frequency. Regarding the change over time in peak PC, the elevation over time developed more in rivaroxaban (29/57; 50.9%, p < 0.05) than in edoxaban (32/101; 31.7%), and rivaroxaban tended to accumulate more than edoxaban. Conclusions: Although drug PC levels of once-daily FXa inhibitors widely varied from peak to trough, FMC levels were maintained within the normal range without daily variations. Rivaroxaban also tended to accumulate over time. The results indicate the low risk of thrombotic events with once-daily FXa inhibitors and its correspondence to the twice-daily regimen.

Apixaban dosing in hemodialysis - can drug level monitoring mitigate controversies?

BackgroundInconsistent study results and contradictory recommendations from health authorities regarding the use of apixaban in patients on hemodialysis have generated considerable uncertainty among clinicians, making investigations of appropriate dosing an unmet need.MethodsWe analyzed pre-dialysis apixaban drug levels from a tertiary care dialysis unit, comparing 2.5 mg once versus twice daily dosing. We applied mixed-effects models including dialysis modality, adjusted standard Kt/V, ultrafiltration, and dialyzer characteristics. We included an exploratory analysis of bleeding events and compared the drug levels of our dialysis patients to those from non-CKD reference populations taking the standard dose of 5 mg twice daily.ResultsWe analyzed 143 drug levels from 24 patients. Mean (SD) age at first drug level measurement was 64.7 (15.9) years (50 % female), median (IQR) follow-up was 12.5 (5.5 – 21) months. For the apixaban 2.5 mg once and twice daily groups, median (IQR) drug levels were 54.4 (< 40 – 72.1) and 71.3 (48.8 – 104.1) ng/mL respectively (P < 0.001). Levels were below the detection limit in 30 % (with 2.5 mg once daily) and 14 % (with 2.5 mg twice daily) respectively. Only dosing group (twice versus once daily) was independently associated with higher drug levels (P = 0.002). Follow-up did not suggest accumulation. The 95th percentile of drug levels did not exceed those of non-CKD populations taking 5 mg twice daily. Median (IQR) drug levels before a bleeding (8 episodes) were higher than those without a subsequent bleeding: 111.6 (83.1 – 129.3) versus 54.8 (< 40 – 77.1) ng/mL (P < 0.001). Concomitant antiplatelet therapy was used in 86% of those with bleeding events versus 6% without bleeding events (P < 0.001).ConclusionsDrug monitoring may be a contributory tool to increase patient safety. Despite non-existing target ranges, drug levels on both edges of the spectrum (e.g. below detectability or beyond the 95th percentiles of reference populations) may improve decision-making in highly individualized risk-benefit analyses.

Secondary prophylaxis of venous thromboembolism (VTE) with low dose apixaban or rivaroxaban in major-thrombophilia carriers.

Direct oral anticoagulants (DOACs) are widely used for treatment and secondary prophylaxis of venous thromboembolism (VTE) and represent the gold standard for VTE secondary prophylaxis, with low-intensity DOACs administration becoming increasingly used worldwide in such scenario. Albeit widespread DOACs usage there are few literature data regarding their efficacy and safety in major thrombophilia carriers and almost no data is available for low intensity apixaban and rivaroxaban as secondary VTE prophylaxis in such patients. The aim of our study is to evaluate and confront the efficacy and safety of low-dose DOACs for VTE secondary prophylaxis, in major thrombophilia carriers vs patients at high risk of VTE recurrence for other reasons. We retrospectively evaluated patients who required long-term anticoagulant secondary prophylaxis to prevent recurrent VTE, treated with apixaban 2.5mg BID or rivaroxaban 10mg daily and that were screened for thrombophilia. The examined patients were 339. Baseline characteristics such as sex, age, obesity rate, smoking, number of previous VTEs and comorbidities (such as cardiovascular diseases, diabetes, mild CKD) were equally distributed in either group. The median low-dose DOACs administration time was 19.20months (IQR 12.17-35.67). During low-dose DOACs treatment, 13 (3.8%) VTE recurrences were observed; 14 bleeding events were registered (4,1%), with no major bleeding (MB), 6 clinically relevant non major bleeding (CRNMB) (1.8%) and 8 minor bleeding (2.3%). No statistically significant difference in the rate of VTE recurrence and/or bleeding events emerged between major thrombophilia carriers and non-major thrombophilia carriers. In multivariate analysis increased risk of VTE recurrence was found for patients with cardiovascular comorbidities (HR 4.00 - p = 0.034) and for patients with more than one previous VTE episode (HR 5.14-p = 0.034). Our data suggest that low-dose DOACs may be effective and safe in secondary VTE prophylaxis for carriers of major thrombophilia with no increase in VTE recurrence and/or bleeding risk.

Impact of Real-World, Off-Label Dose of Apixaban on Long-Term Clinical Outcomes in Patients with Atrial Fibrillation and CKD

Impact of Real-World, Off-Label Dose of Apixaban on Long-Term Clinical Outcomes in Patients with Atrial Fibrillation and CKD

Assessing Direct Oral Anti-Coagulant And Therapeutic Low Molecular Weight Heparin Prescriptions At A University Teaching Hospital

Abstract Background A 2017-2018 survey identified anti-thrombotics as the most commonly implicated agents in reported medication incidents across Irish acute hospitals [State Claims Agency, 2020, Medication Incidents Report (2017-2018)]. Of the top 10 anti-thrombotics reported, 2 were Low Molecular Weight Heparins (LMWHs) and 3 were Direct Oral Anti-Coagulants (DOACs). 3 years after the survey results were published, we audited our hospital's compliance with the Health Service Executive's guidelines for prescribing DOACs and LMWHs. Methods Over 3 consecutive weeks, data was collected by doctors and clinical pharmacists across 6 wards and the intensive and coronary care units. In-patients on a DOAC or therapeutic LMWH were chosen for kardex and laboratory result review. Results 83 patients were included. The average age was 79 years. 81%(n=67) were on a DOAC. 91% were being treated for non-valvular atrial fibrillation (NVAF), 3% for pulmonary embolism (PE), 3% for deep vein thrombosis and 3% had no indication documented. 33%(n=22) had indications for dose reduction but only 77%(n=17) of them were prescribed the appropriate reduced dose. 3%(n=2) had no dose reduction indications but were inappropriately prescribed a reduced dose. 3%(n=2) were on dialysis, 1%(n=1) had their creatinine clearance persistently below 15ml/min and 1%(n=1) inappropriately received once daily dosing of apixaban for 3 days. 19%(n=16) of all participants were on therapeutic LMWH. Treatment indications included acute coronary syndrome in 63%, suspected PE in 19%, newly diagnosed NVAF in 6% and bridging anti-coagulation while a DOAC is temporarily held in 13%. 6%(n=1) were inappropriately prescribed an under-dose. Conclusion Overall, there was an error rate of 16%(n=11) in DOAC prescriptions and 6%(n=1) in LMWH prescriptions. To address this, we propose an educational intervention for prescribers and the introduction of e-prescriptions with built-in alerts for errors. We plan to re-audit once these recommendations are implemented.

Plasma apixaban concentrations and thrombin generation assay parameters in response to dose reduction for atrial fibrillation.

To investigate plasma apixaban concentrations and thrombin generation assay (TGA) parameters across different apixaban doses in atrial fibrillation patients who had dose-reduction criteria for apixaban. This observational study included 374 patients (mean age 75.6 ± 7.7 years, 54.8% female) with dose-reduction criteria for apixaban. The patients were divided into 3 groups: (i) on-label standard dose (5 mg twice daily, n =166); (ii) on-label reduced dose (2.5 mg twice daily, n =55); and (iii) off-label underdose (2.5 mg twice daily, n =153). Apixaban concentrations determined via the anti-Xa assay and TGA parameters were compared at trough levels. The off-label underdose group exhibited significantly lower apixaban trough concentrations than the on-label reduced-dose and standard-dose groups (56.7 ± 42.9 vs. 83.7 ± 70.4 vs. 129.9 ± 101.8 ng/mL, all P <.001). Less than 70% of all patients fell within the expected range of apixaban concentrations. Proportions exceeding the upper limit of the expected range were significantly lower in the off-label underdose group (1.3%) than in the on-label reduced-dose (9.1%, P =.005) and standard-dose (12.7%, P <.001) groups. The TGA parameters showed the on-label standard-dose group displaying the lowest thrombogenic profiles. Lower creatinine clearance was the most significant predictor of higher apixaban concentrations. Off-label underdosed apixaban resulted in lower apixaban concentrations than both on-label standard and reduced-dose regimens. A considerable proportion of the patients exhibited apixaban concentrations outside the expected range, suggesting the potential benefits of plasma concentration monitoring. Further studies are needed to compare dosages directly, investigate the impact of plasma apixaban concentration monitoring and validate the current dose-reduction criteria.

Apixaban plasma concentrations before and after catheter ablation for atrial fibrillation.

Catheter ablation in patients with atrial fibrillation is associated with a transient increase in thromboembolic risk and adequate anticoagulation is highly important. When patients are anticoagulated with apixaban, monitoring of plasma concentrations of the drug is not routinely performed. This study aimed to assess the influence of clinical patient characteristics, concomitant drug treatment and self-reported adherence on apixaban concentrations, and to describe the intra- and inter-individual variability in apixaban concentrations in this group of patients. Method Apixaban concentrations from 141 patients were measured in plasma one week before ablation and two, six and ten weeks after ablation, employing ultra-high performance liquid chromatography coupled with tandem mass spectrometry. In samples not obtained at trough, apixaban concentrations were adjusted to trough levels. Self-reported adherence was registered by means of the 8-item Morisky Medication Adherence Scale before and after ablation. There were statistically significant, positive correlations between apixaban concentrations and increased age, female sex, lower glomerular filtration rate, higher CHA2DS2-VASc score, use of cytochrome P450 3A4 and/or p-glycoprotein inhibitors, and use of amiodarone. Self-reported adherence was generally high. The mean intra-individual and inter-individual coefficients of variation were 29% and 49%, respectively. In patients undergoing catheter ablation for atrial fibrillation, age, sex, renal function, interacting drugs and cerebrovascular risk profile were all associated with altered plasma apixaban concentration. In this group of patients with a generally high self-reported adherence, intra-individual variability was modest, but the inter-individual variability was substantial, and similar to those previously reported in other patient apixaban-treated populations. If a therapeutic concentration range is established, there might be a need for a more flexible approach to apixaban dosing, guided by therapeutic drug monitoring.

Implementation and Evaluation of Clinical Decision Support for Apixaban Dosing in a Community Teaching Hospital.

This study aimed to describe and evaluate the transition from a specialty service-based prospective order approval system to a computerized clinical decision support (CCDS) tool for apixaban dosing at a community teaching hospital. The primary objective was to assess the impact of the transition on the appropriateness of apixaban prescribing. A CCDS tool for apixaban dosing was developed and implemented using interprofessional collaboration. A retrospective chart review was conducted for apixaban orders placed before (preimplementation) and after (postimplementation) the CCDS transition. The primary outcome was the percent change in inappropriate apixaban orders, with secondary outcomes exploring percent change of apixaban orders with inappropriate dosing in different patient groups and indications per package insert. Fifty orders were assessed in both arms, with 8% of orders preimplementation and 10% postimplementation deemed inappropriate. After accounting for questionable orders, overall appropriateness of prescribing was 88% preimplementation and 84% postimplementation ( P = 0.7). Challenges with implementation of CCDS included working with available information technology resources and facilitating acceptance of a new ordering process. The implementation of a CCDS tool for apixaban dosing at a community teaching hospital demonstrated comparable rates of appropriateness to the previous specialty service-based approval process. While the transition streamlined resources and improved efficiency, ongoing efforts are needed to address specific dosing challenges. Future research should explore the sustainability and generalizability of CCDS tools in diverse healthcare settings.

Clinical characteristics of apixaban prescription in AF patients with single dose-reduction criterion: the ASPIRE (efficAcy and safety of aPixaban in rEal-world practice in Korean frail patients with atrial fibrillation) study.

Data on off-label reduced dose risk among patients with atrial fibrillation (AF) who qualify for a single-dose reduction of apixaban is scarce. We prospectively assessed apixaban dosing and clinical characteristics in AF patients meeting a dose reduction criterion. The multicentre, prospective cohort study, the efficAcy and Safety of aPixaban In REal-world practice in Korean frail patients with AF (ASPIRE), encompasses patients with AF who met the criteria for a single-dose reduction of apixaban and were given varying doses of apixaban, either the on-label standard dose or the off-label reduced dose. Of 2,000 patients (mean age 74.3 ± 7.9 years, 55.8% women), 29.7% were ≥80 years, 62.6% weighed ≤60 kg, and 7.8% had serum creatinine ≥1.5 mg/dL. Of these, 51.3% were prescribed an off-label reduced dose of apixaban. The off-label group was characterized with older age, more comorbidities, and antiplatelet agents, while the on-label group had more prior strokes. Physicians preferred off-label reduced dose in the "marginal zone," defined as age 75-80 years, weight 60-65 kg, and creatinine levels 1.2-1.5 mg/dL. In real-world clinical setting of the Korean population, off-label reduced dose apixaban was administered to nearly half of the patients who qualified for a single dose reduction. This reduced dosage was more commonly prescribed to patients with frail characteristics, while patients with a history of stroke were more often given the standard dose as per the label. A future study is planned to contrast the safety and effectiveness of the standard dose against the reduced dose of apixaban in this population.

Off-Label Reduced Dose Apixaban in Older Adults With Atrial Fibrillation and Associated Outcomes.

Apixaban is commonly used to prevent stroke in older adults with nonvalvular atrial fibrillation (AF). Although its package insert has specific dose reduction criteria, providers may dose reduce outside of these parameters based on clinical scenarios. The primary objective was to determine the incidence of apixaban off-label reduced dosing, while secondarily determining the safety and efficacy outcomes associated with such dosing. A retrospective analysis of patients aged 65 and older with orders for apixaban for AF was institutional review board (IRB)-approved and conducted across 3 academic medical centers. Patients receiving off-label reduced-dose apixaban (ie, "underdosed") were matched to a cohort of patients dosed according to the package insert at the standard dosing (5 mg twice daily) using stratified random sampling. Secondary outcomes included 1-year incidence of major bleeding, clinically relevant non-major bleeding (CRNMB), stroke or transient ischemic attack (TIA), and mortality. The Fisher exact tests were used to compare between-group differences. Of the 1172 patients meeting initial inclusion criteria, 201 (17%) were dosed off-label, with 175 (15%) "underdosed." The 147 "underdosed" patients with documented follow-up were matched with 139 patients receiving standard Food and Drug Administration (FDA)-labeled dosing. There were no significant differences in incidence of stroke (2.7% vs 2.2%), major bleeding (0% vs 0.7%), and CRNMB (2.7% vs 1.4%) in the off-label reduced dosing versus standard dosing groups. All-cause mortality was higher in the off-label reduced-dose group (16 [10.9%] vs 2 [1.4%], P < 0.05). Older adults with nonvalvular AF are commonly prescribed lower-than-recommended doses of apixaban. However, no significant association was found between empiric off-label reduced dosing and stroke or bleeding outcomes.

A retrospective review of recurrent venous thromboembolism in patients with cancer with direct factor Xa inhibitors.

e24136 Background: Venous thromboembolism (VTE) in cancer patients is a significant cause of morbidity and mortality. People with malignancies are at an increased risk of thrombosis compared to the normal population. Regimens that include platinum-based agents and vascular endothelial growth factor (VEGF) inhibitors have a higher risk of thromboembolism1. The recent ASCO 2023 guidelines for VTE prophylaxis and treatment have advised that direct factor Xa inhibitors are a suitable option for initial and long-term treatment for VTE, given patient preference of oral over subcutaneous administration of anti coagulation2. In our retrospective review of a single centre in Western Australia, we have identified twelve patients who have developed thromboembolic events whilst on direct oral anticoagulation. Methods: Electronic patient records were reviewed for oncology patients attending between 2016 and 2023 at a single centre in Western Australia.Diagnosis of VTE and subsequent treatment was confirmed from radiology and medication records. Twelve patients were identified, and data was recorded and analysed. Results: 12 patients were identified with recurrent VTE whilst on direct factor Xa inhibitors. The median age was 59.5 years (range 50-71). The most common associated malignancies were pancreatic, ovarian and lung cancer. Others include breast, vulval, colon and gastroesophageal cancer. Two thirds of patients were metastatic at diagnosis (n = 8). Common sites of thrombosis include the lower limbs at both initial [n = 6] and recurrent [n = 4] presentation. All patients were treated with therapeutic doses of rivaroxaban (n = 8) or apixaban (n = 4) at the time of of initial or recurrent thrombotic event. Median time to initial thrombotic event was 4.5 months from diagnosis compared to recurrent VTE [5 months]. All patients were changed to either LMWH (n = 10) or unfractionated heparin (n = 2). Ten patients [83.3%] did not have further thrombosis post switching to heparin. One patient had recurrent pulmonary emboli on imaging despite heparin administration, and the other had an IVC filter insertion. Conclusions: VTE is a common complication for oncology patients. Given our results, clinicians should be suspicious for recurrent VTE for patients on direct factor Xa inhibitors. There is an argument for enoxaparin or dalteparin to be better options, particularly in those high risk. Whilst patient preference for an oral option is desirable, further investigation is needed to directly compare the differing direct factor Xa inhibitors and the rates of VTE recurrence.

#606 Impact of real-world off-label dose of apixaban on long-term clinical outcomes in patients with atrial fibrillation and chronic kidney disease

Abstract Background and Aims Apixaban represent one of the cornerstone treatments to prevent cardioembolic events in patients with nonvalvular atrial fibrillation (NVAF). However, the choices of Apixaban dose guided by the decision-making process of the physician, which considers specific according to kidney functions are inconsistent in the real-world practice. The objective of the present study is to evaluate the effects of real-world Off-label dose of Apixaban on long-term clinical outcomes in NVAF patients with chronic kidney disease (CKD). Method Our database of AF patients diagnosed with CKD from 2018 to 2023 was used to obtain laboratory, echocardiography, electrocardiogram (ECG), and clinical outcomes data. Inclusion criteria were all AF patients with CKD using Apixaban. And we compared bleeding, systemic thrombotic events including stroke/systemic embolism and death according to off-label real -world dose of Apixaban. Results Among 635 patients with AF and CKD (76.9 ± 10.4 years), 335 (52.8%) patients took off-label underdosed Apixaban. Difference in the baseline characteristics was not observed among patients including CHA2DS2 VASc score and HASBLED score. During the median 18-month follow-up, a lower incidence of bleeding events (P = 0.001) was observed in the off-label underdosed Apixaban group compared to those with standard dose or off-label overdosed Apixaban. However, there was no significant difference of systemic thrombotic events including stroke/systemic embolism and death according to off-label real-world dose of Apixaban (off-label underdose vs. standard dose, P = 1.000; off-label overdose vs. standard dose, P = 1.000; off-label underdose vs. off-label overdose, P = 0.609). In multivariate analysis, HASBLED score was independent risk factors for bleeding events (OR 9.650; CI 1.998-46.622; P = 0.005). Conclusion Compared with standard or off-label overdose of Apixaban, off-label underdose of Apixaban was associated with a lower risk of bleeding in patients with AF and CKD, with no difference in the risk of stroke/systemic embolism or death, supporting the apixaban dosing tailored to specific clinical features and drug pharmacokinetics of the Asian patients.

Evaluation of Apixaban standard dosing in underweight patients with non-valvular atrial fibrillation: a retrospective cohort study

BackgroundRecent guidelines recommend using direct oral anticoagulants (DOACs) as first-line agents in patients with non-valvular atrial fibrillation (NVAF). Research is currently investigating the use of Apixaban in underweight patients, with some results suggesting altered pharmacokinetics, decreased drug absorption, and potential overdosing in this population. This study examined the effectiveness and safety of standard Apixaban dosing in adult patients with atrial NVAF weighing less than 50 kg.MethodsThis is a retrospective cohort study conducted at King Abdulaziz Medical City (KAMC); adult patients with a body mass index (BMI) below 25 who received a standard dose of Apixaban (5 mg twice daily) were categorized into two sub-cohorts based on their weight at the time of Apixaban initiation. Underweight was defined as patients weighing ≤ 50 kg, while the control group (Normal weight) comprised patients weighing > 50 kg. We followed the patients for at least one year after Apixaban initiation. The study’s primary outcome was the incidence of stroke events, while secondary outcomes included bleeding (major or minor), thrombosis, and venous thromboembolism (VTE). Propensity score (PS) matching with a 1:1 ratio was used based on predefined criteria and regression model was utilized as appropriate.ResultsA total of 1,433 patients were screened; of those, 277 were included according to the eligibility criteria. The incidence of stroke events was lower in the underweight than in the normal weight group at crude analysis (0% vs. 9.1%) p-value = 0.06), as well in regression analysis (OR (95%CI): 0.08 (0.001, 0.76), p-value = 0.002). On the other hand, there were no statistically significant differences between the two groups in the odds of major and minor bleeding (OR (95%CI): 0.39 (0.07, 2.03), p-value = 0.26 and OR (95%CI): 1.27 (0.56, 2.84), p-value = 0.40, respectively).ConclusionThis exploratory study revealed that underweight patients with NVAF who received standard doses of Apixaban had fewer stroke events compared to normal-weight patients, without statistically significant differences in bleeding events. To confirm these findings, further randomized controlled trials with larger sample sizes and longer observation durations are required.

Pharmacokinetics of apixaban in patients undergoing pancreaticoduodenectomy (PAP-UP).

The impact of pancreaticoduodenectomy on absorption of drugs in the duodenum remains largely unknown. We aim to characterize the pharmacokinetics of apixaban in patients who had previously undergone pancreaticoduodenectomy. A single 10-mg dose of apixaban was administered to 4 volunteers who underwent pancreaticoduodenectomy at least 6 months prior. The maximum plasma apixaban concentration (Cmax) and area under the plasma concentration time-curve (AUC0-24, AUC0-inf) were compared against healthy historical control subjects (N = 12). Geometric mean ratios (GMR) with 90% confidence interval (CI) were calculated for determination of comparative bioequivalence. In pancreaticoduodenectomy patients, AUC0-24 and AUC0-inf were 1,861 and 2,080 ng×h/mL, respectively. The GMRs of AUC0-24 and AUC0-inf between study subjects and healthy controls were 1.27 (90% CI 0.88 - 1.83) and 1.18 (90% CI 0.82 - 1.72). The mean Cmax of apixaban was 201 ng/mL (SD 15.6) occurring at a median tmax of 3.25 hours (range 2.5 - 4 hours). The GMR of Cmax between study subjects and healthy controls was 1.12 (90% CI 0.77 - 1.63). The pharmacokinetic characteristics of apixaban in subjects who had undergone pancreaticoduodenectomy are not significantly different from those of healthy controls. Though the sample size of this study is small, results suggest that no change to apixaban dose regimen is needed in patients who have had a pancreaticoduodenectomy.

D-dimer and risk of venous thromboembolism recurrence: Comparison of two studies with similar designs but different laboratory and clinical results

BackgroundD-dimer testing may help deciding the duration of anticoagulation in subjects at high risk of venous thromboembolism (VTE) recurrence. Two management studies on this issue have been published (DULCIS in 2014 and APIDULCIS in 2022). They had similar designs but had important different results. Aim of this article is to compare their results. MethodsBoth studies were finalized to extend anticoagulation [with vitamin K anticoagulants (VKAs) in DULCIS or apixaban 2.5 mg BID (kindly provided by BMS-Pfizer Collaboration) in APIDULCIS] only in patients with positive D-dimer results. ResultsMore D-dimer assays resulted positive in APIDULCIS than in DULCIS (61.1 % vs 47.7 %, respectively; p < 0.0001). While only 4 (0.5 %) refused low dose apixaban in APIDULCIS, the 22.6 % of patients with positive D-dimer refused to resume VKAs in DULCIS; their rates of recurrence were 187 and 8.8 per 100 person-years, respectively (incidence rate ratio [IRR]: 21.2). The incidence of bleeding was low in those receiving apixaban vs those who resumed VKAs (0.4 vs 2.3 per 100 person-years, respectively; IRR 0.17;). While the recurrence rate was low and similar in the studies in subjects who resumed anticoagulation, it was significantly higher in APIDULCIS than in DULCIS in those who stopped anticoagulation for negative D-dimer (5.6 vs 3.0 per 100 person-years, respectively; IRR 1.9). ConclusionThe low dose Apixaban for extended VTE treatment is effective and safe, and well accepted by patients. Why subjects who stopped anticoagulation for negative D-dimer had a higher recurrence rate in APIDULCIS than in DULCIS remains to be explained.

(1398) - Challenging the Conventional Wisdom of Apixaban Dose Adjustments in Heart Transplants on Posaconazole with and without Dialysis

(1398) - Challenging the Conventional Wisdom of Apixaban Dose Adjustments in Heart Transplants on Posaconazole with and without Dialysis

Secondary Prophylaxis of Venous Thromboembolism (VTE) with Low Dose Apixaban or Rivaroxaban: Results from a Patient Population with More than 2 Years of Median Follow-up.

Direct oral anticoagulants (DOACs) are widely used for the treatment and secondary prophylaxis of venous thromboembolism (VTE). Nowadays, DOACs represent the gold standard for long-term anticoagulation, with low-intensity DOACs administration becoming increasingly used worldwide in such scenario. Albeit low-intensity apixaban and rivaroxaban are approved for clinical usage as secondary VTE prophylaxis, there are few literature data regarding their efficacy and safety with a long follow-up. The aim of our study was to evaluate the efficacy and safety of low-dose DOACs for VTE secondary prophylaxis in patients at high risk of VTE recurrence. We retrospectively evaluated patients who required long-term anticoagulant secondary prophylaxis to prevent recurrent VTE, treated with apixaban 2.5 mg BID or rivaroxaban 10 mg daily with a follow-up ≥ 12 months. The examined patients were 323. The median low-dose DOAC administration time was 25.40 months (IQR 13.93-45.90). Twelve (3.7%) VTE recurrences were observed; 21 bleeding events were registered (6.5%), including one episode of Major bleeding (MB) (0.3%), 8 Clinically relevant nonmajor bleeding (CRNMB) (2.5%) and 12 minor bleeding (3.7%). No statistically significant difference in the rate of VTE recurrence and/or bleeding events emerged between the rivaroxaban and apixaban groups. Patients included in the study for multiple episodes of VTE presented a significantly higher risk of a new VTE recurrence during low-intensity DOAC. Our data suggest that low-dose DOACs may be effective and safe in secondary VTE prophylaxis in patients at high risk of VTE recurrence; however, attention might be needed in their choice in such a scenario for patients who experienced multiple episodes of VTE.