Premature permanent discontinuation of apixaban or warfarin in patients with atrial fibrillation

Examining an Interaction Between Plasma Exchange and Apixaban Resulting in an Acute Ischemic Stroke

Objective: Therapeutic drug monitoring is not routinely considered necessary in patients undergoing plasma exchange; however, it is possible for serum concentrations of select medications to be impacted by this procedure. Case: We describe a 50-year-old patient who presented to our facility with new onset aphasia and right-sided weakness. Despite presenting with a National Institute of Health Stroke Severity (NIHSS) score of 23, the patient did not receive fibrinolytic therapy due to his being anticoagulated with apixaban for atrial fibrillation. The patient instead underwent an emergent thrombectomy which resulted in a post-operative Thrombolysis in Cerebral Infarction (TICI) score of 3. The patient had a significant past medical history including numerous previous strokes necessitating assistance with activities of daily living, atrial fibrillation, chronic kidney disease, and thrombocytopenic purpura, for which he was receiving twice weekly plasma exchange and immunomodulatory therapy. The patient's last plasma exchange session was approximately 24 hours prior to admission, leading us to hypothesize that the patient's plasma exchange may have been implicated in the removal of apixaban from the serum and precipitating a stroke. Discussion/Conclusions: Heterogeneity of data exists when evaluating the effect of plasma exchange on apixaban. Although the drug properties of apixaban, including its low volume of distribution and high plasma protein binding capacity, support the notion that it may be vulnerable to removal through plasma exchange, only one other case report has been published on this phenomenon.

Payer formulary tier increases of apixaban: how patients respond and potential implications

OBJECTIVE

To assess potential impacts of formulary tier increases of apixaban-an efficacious oral anticoagulant (OAC) for preventing stroke in patients with atrial fibrillation (AF)-on patients' prescription drug plan (PDP) switching and OAC treatment patterns.

METHODS

Nationwide claims data for Medicare beneficiaries with Parts A, B, and D (100% sample) were used to assess apixaban-treated AF patients who faced a formulary tier increase for apixaban in 2017 by their Part D PDP. Patients' out-of-pocket (OOP) costs for apixaban were described, along with PDP switching and OAC treatment patterns.

RESULTS

Among 1845 included patients, 97.7% had apixaban on tier 3 of their plan's formulary in 2016 and faced its increase to tier 4 for 2017. Approximately 4% (N = 81) of patients pre-emptively switched to a different PDP for 2017 with almost all switching to plans with apixaban on a lower formulary tier and 85.2% continuing apixaban treatment. Among the 96% (N = 1764) of patients who remained on the same PDP for 2017, over half (57.5%) continued apixaban treatment, despite increased OOP costs ($54 vs. $135 for a 30-day supply in 2016 vs. 2017). Only 12.4% of those who remained on the same plan for 2017 switched to another OAC, while as much as 30.1% discontinued OACs. These discontinuers exhibited higher comorbidity burdens than patients continuing on any OAC.

CONCLUSION

The majority of patients continued on apixaban despite higher OOP cost, suggesting patients' reluctance to change treatment for non-medical reasons; however, 30% of patients discontinued OAC treatment after higher apixaban tier placement.

Payer formulary exclusions of apixaban: how patients respond and potential implications

In recent years, US payers have increased usage of formulary exclusions as a means to help manage costs. Earlier this year, one of the largest pharmacy benefit managers in the country added Eliquis (apixaban), the most widely used anticoagulant, to its list of excluded medicines from its formulary, raising concerns by physicians and patients. In this commentary, we examine the potential impacts of formulary exclusion of a drug like apixaban-a treatment for patients with atrial fibrillation and venous thromboembolism to help prevent stroke and clotting events and which has been demonstrated to have a strong efficacy and safety profile. We discuss the effect of formulary exclusions on patients' ability to access the most clinically appropriate treatment for their health needs, along with possible effects on their health and well-being. We also report descriptive results on apixaban-treated patients with traditional Medicare coverage who faced a formulary exclusion of apixaban in 2017, and these patients' observed behaviors. We found that the majority of these patients remained on apixaban either through pre-emptively switching to a different Part D drug plan with apixaban coverage or applying for formulary exception. Our findings suggest that formulary exclusion did not help to achieve the goal of switching patients to less costly medications but created additional hurdles for patients to access their preferred treatment and increased patient burden. Alternative ways to manage payer costs may be needed to help avoid poor outcomes and reduce the burden placed on patients in their efforts to access life-saving medications.

Termination Based on Event Accrual in Per Protocol Versus Intention to Treat in the ROCKET AF Trial

Background

In event‐driven clinical trials, study termination is based on accrual of a target number of primary efficacy events. For noninferiority trials in which superiority is conditionally examined, the ideal cohort in which to track event accrual is unclear. We used data from the ROCKET AF (Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared With Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation) trial to determine the effect of primary efficacy‐event tracking in the per‐protocol cohort during the on‐treatment period versus the intention‐to‐treat (ITT) cohort during the ITT period.

Methods and Results

ROCKET AF was terminated after accruing 429 primary efficacy events (stroke or systemic embolism) in the per‐protocol cohort during the on‐treatment period for noninferiority. We identified the date on which 429 events occurred in the ITT cohort during the ITT period. We performed noninferiority and superiority analyses based on hypothetical study termination on this date. ROCKET AF would have terminated 226 days earlier if events were tracked during the ITT period. Similar to the main trial findings, rivaroxaban would have met noninferiority versus warfarin for the primary efficacy end point (hazard ratio [HR], 0.77; 95% CI, 0.62–0.96; P<0.001). In contrast to the main trial findings, rivaroxaban would have met superiority for the primary efficacy end point (HR, 0.82; 95% CI, 0.68–0.99; P=0.038). In both termination scenarios, rivaroxaban was associated with a lower risk of intracranial hemorrhage and similar risk of other safety end points.

Conclusions

Clinical trial termination based on event accrual in the ITT cohort versus the per‐protocol cohort may have important implications on trial results depending on rates of study drug discontinuation and event rates off treatment.

Safety and Efficacy of Vitamin K Antagonists versus Rivaroxaban in Hemodialysis Patients with Atrial Fibrillation: A Multicenter Randomized Controlled Trial

BACKGROUND

In patients with normal renal function or early stage CKD, the risk-benefit profile of direct oral anticoagulants (DOACs) is superior to that of vitamin K antagonists (VKAs). In patients on hemodialysis, the comparative efficacy and safety of DOACs versus VKAs are unknown.

METHODS

In the Valkyrie study, 132 patients on hemodialysis with atrial fibrillation were randomized to a VKA with a target INR of 2-3, 10 mg rivaroxaban daily, or rivaroxaban and vitamin K2 for 18 months. Patients continued the originally assigned treatment and follow-up was extended for at least an additional 18 months. The primary efficacy end point was a composite of fatal and nonfatal cardiovascular events. Secondary efficacy end points were individual components of the composite outcome and all-cause death. Safety end points were life-threatening, major, and minor bleeding.

RESULTS

Median (IQR) follow-up was 1.88 (1.01-3.38) years. Premature, permanent discontinuation of anticoagulation occurred in 25% of patients. The primary end point occurred at a rate of 63.8 per 100 person-years in the VKA group, 26.2 per 100 person-years in the rivaroxaban group, and 21.4 per 100 person-years in the rivaroxaban and vitamin K2 group. The estimated competing risk-adjusted hazard ratio for the primary end point was 0.41 (95% CI, 0.25 to 0.68; P=0.0006) in the rivaroxaban group and 0.34 (95% CI, 0.19 to 0.61; P=0.0003) in the rivaroxaban and vitamin K2 group, compared with the VKA group. Death from any cause, cardiac death, and risk of stroke were not different between the treatment arms, but symptomatic limb ischemia occurred significantly less frequently with rivaroxaban than with VKA. After adjustment for competing risk of death, the hazard ratio for life-threatening and major bleeding compared with the VKA group was 0.39 (95% CI, 0.17 to 0.90; P=0.03) in the rivaroxaban group, 0.48 (95% CI, 0.22 to 1.08; P=0.08) in the rivaroxaban and vitamin K2 group and 0.44 (95% CI, 0.23 to 0.85; P=0.02) in the pooled rivaroxaban groups.

CONCLUSIONS

In patients on hemodialysis with atrial fibrillation, a reduced dose of rivaroxaban significantly decreased the composite outcome of fatal and nonfatal cardiovascular events and major bleeding complications compared with VKA.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Oral Anticoagulation in Hemodialysis, NCT03799822.

Impact of anemia on clinical outcomes of patients with atrial fibrillation: The COOL-AF registry

BACKGROUND

To determine whether anemia is an independent risk factor for ischemic stroke and major bleeding in patients with non-valvular atrial fibrillation (NVAF).

HYPOTHESIS

Anemia in patients with NVAF increase risk of clinical complications related to atrial fibrillation.

METHODS

We conducted a prospective multicenter registry of patients with NVAF in Thailand. Demographic data, medical history, comorbid conditions, laboratory data, and medications were collected and recorded, and patients were followed-up every 6 months. The outcome measurements were ischemic stroke or transient ischemic attack (TIA), major bleeding, heart failure (HF), and death. All events were adjudicated by the study team. We analyzed whether anemia is a risk factor for clinical outcomes with and without adjusting for confounders.

RESULTS

There were a total of 1562 patients. The average age of subjects was 68.3 ± 11.5 years, and 57.7% were male. The mean hemoglobin level was 13.2 ± 1.8 g/dL. Anemia was demonstrated in 518 (33.16%) patients. The average follow-up duration was 25.8 ± 10.5 months. The rate of ischemic stroke/TIA, major bleeding, HF, and death was 2.9%, 4.9%, 1.8%, 8.6%, and 9.2%, respectively. Anemia significantly increased the risk of these outcomes with a hazard ratio of 2.2, 3.2, 2.9, 1.9, and 2.8, respectively. Oral anticoagulants (OAC) was prescribed in 74.8%; warfarin accounts for 89.9% of OAC. After adjusting for potential confounders, anemia remained a significant predictor of major bleeding, heart failure, and death, but not for ischemic stroke/TIA.

CONCLUSION

Anemia was found to be an independent risk factor for major bleeding, heart failure, and death in patients with NVAF.