Rivaroxaban shows promise as effective therapy for cancer patients with venous thromboembolic disease

Effectiveness and safety of rivaroxaban compared with low-molecular-weight heparin in cancer-associated thromboembolism

Guidelines provide differing recommendations regarding direct-acting oral anticoagulants vs low-molecular-weight heparin (LMWH) for treatment of cancer-associated thrombosis (CAT). This study was undertaken to evaluate the effectiveness and safety of rivaroxaban vs LMWH for treatment of CAT. Using US Surveillance, Epidemiology and End Results-Medicare-linked data from 2013 through 2016, we evaluated adults with active breast, lung, ovarian, or pancreatic cancer, who were admitted to the hospital or treated in the emergency department for CAT and were prescribed rivaroxaban or LMWH for outpatient anticoagulation. Patients with luminal gastrointestinal or genitourinary cancers were excluded. Rivaroxaban and LMWH users were 1:1 propensity score matched. Outcomes included the composite of recurrent thrombosis or major bleeding, each outcome separately, and mortality at 6 months, using an intent-to-treat approach. On-treatment analysis after 12 months was also performed. Proportional hazards models for the subdistribution of competing risk were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). We included 529 rivaroxaban- and 529 LMWH-treated patients with CAT. Rivaroxaban was not associated with differences in risk of the composite outcome (HR, 0.71; 95% CI, 0.41-1.22), major bleeding (HR, 1.01; 95% CI, 0.50-2.01), or mortality (HR, 0.87; 95% CI, 0.70-1.07) vs LMWH, but it reduced recurrent thrombosis (HR, 0.37; 95% CI, 0.15-0.95). On-treatment analysis at 12 months showed similar results. Rivaroxaban may be a reasonable alternative to LMWH for patients with CAT without gastrointestinal or genitourinary cancer.

Evaluation of direct oral anticoagulants for the treatment of cancer-associated thrombosis: an update

Cancer is associated with an increased risk of venous thromboembolism of four to sixfold. Cancer-related interventions such as chemotherapy, hormonal therapy and indwelling central venous catheters also increase the risk of venous thromboembolism. Low molecular weight heparin for at least 3-6 months is the current standard of care for the treatment of cancer associated venous thromboembolism. Anticoagulation should be continued as long as the cancer is active. Over the past few years, direct oral anticoagulants have emerged, including one direct thrombin inhibitor (dabigatran etexilate) and three factor Xa inhibitors (apixaban, edoxaban and rivaroxaban). In the randomized controlled trials comparing direct oral anticoagulants with vitamin K antagonists, the direct oral anticoagulants all provide non-inferior in prevention of thromboembolic events in patients with atrial fibrillation, for the prevention and treatment of venous thromboembolism and in acute coronary syndrome. In people with cancer, these drugs have emerged as attractive alternatives for the treatment of venous thromboembolism with the potential to overcome the limitations of low molecular weight heparin. Randomized controlled studies comparing direct oral anticoagulants to low molecular weight heparin in cancer patients are still limited and direct oral anticoagulants are not recommended for the treatment of cancer associated venous thromboembolism yet. However, new emerging data are supporting the use of direct oral anticoagulants in cancer-associated thrombosis. Here, we review recent data on the evidence related to the efficacy and safety of direct oral anticoagulants for the treatment of venous thromboembolism in patients with cancer.

Direct Oral Anticoagulant Drugs: On the Treatment of Cancer-Related Venous Thromboembolism and their Potential Anti-Neoplastic Effect

Cancer patients develop a hypercoagulable state with a four- to seven-fold higher thromboembolic risk compared to non-cancer patients. Thromboembolic events can precede the diagnosis of cancer, but they more often occur at diagnosis or during treatment. After malignancy itself, they represent the second cause of death. Low molecular weight heparins are the backbone of the treatment of cancer-associated thromboembolism. This treatment paradigm is possibly changing, as direct oral anticoagulants (DOACs) may prove to be an alternative therapeutic option. The currently available DOACs were approved during the first and second decades of the 21st century for various clinical indications. Three molecules (apixaban, edoxaban and rivaroxaban) are targeting the activated factor X and one (dabigatran) is directed against the activated factor II, thrombin. The major trials analyzed the effect of these agents in the general population, with only a small proportion of cancer patients. Two published and several ongoing studies are specifically investigating the use of DOACs in cancer-associated thromboembolism. This article will review the current available literature on the use of DOACs in cancer patients. Furthermore, we will discuss published data suggesting potential anti-cancer actions exerted by non-anticoagulant effects of DOACs. As soon as more prospective data becomes available, DOACs are likely to be considered as a potential new therapeutic option in the armamentarium for patients suffering of cancer-associated thromboembolism.

Treatment of Venous Thromboembolism in Cancer. Historical Perspective and Evolving Role of the Direct Oral Anticoagulants

The management of cancer-associated thrombosis (CAT) is complex, and treatment strategies have been evolving over the past 15 years. It is well recognized that oral vitamin K antagonists are difficult to use in cancer patients, with higher rates of treatment failure and bleeding complications than in non-cancer patients. Low-molecular-weight-heparin (LMWH) became the widely accepted standard of care for treatment of cancer-associated thrombosis, following the CLOT study comparing dalteparin with warfarin in 2003. LMWH remains widely used for the treatment of CAT. However, in the past two years, several studies have served to validate direct oral anticoagulants as a safe and effective alternative to LMWH. Two randomized clinical trials comparing edoxaban and rivaroxaban with dalteparin, and several retrospective studies have shown the efficacy of edoxaban and rivaroxaban for the treatment of CAT. However, there is an evidence of increased bleeding with the DOACs, particularly gastrointestinal or urinary tract bleeding in patients with lesions within the gastrointestinal or urinary tracts. This chapter discusses the ongoing development of optimal treatment strategies for cancer-associated thrombosis.

Thrombosis and Hemostasis in Cancer. Scope of the Problem and Overview

"The frequent concurrence of phlegmasia alba dolens with an appreciable cancerous tumor, led me to the inquiry whether a relationship of cause and effect did not exist between the two, and whether the phlegmasia was not the consequence of the cancerous cachexia." (translated from the original French). This famous quote, delivered in a lecture by Armand Trousseau in 1865, is widely recognized as the initial and insightful understanding of the relationship of thrombosis and cancer.Although the association of thrombosis with cancer has been recognized for over 150 years, only recently has there been meaningful advances in our understanding of the relationship. Contemporary translational research tools have greatly enhanced our understanding the unique aspects of the pathophysiology of the relationship; how cancer cells exploit multiple aspects of the coagulation system for primary and metastatic growth leading, leading to an increased thrombotic risk. Further, there has been a growing appreciation of the complexity of the treatment of cancer-associated thrombosis. The superiority of low molecular weight heparin over warfarin, published in 2003, represented the first important divergence from the approach to management of thrombosis in the non-cancer population. With the introduction of the new generation of anticoagulants, the direct oral anticoagulants, there has been continued evolution of management guidelines.This text presents a much needed and comprehensive update of the field of thrombosis and hemostasis in cancer. We are fortunate to have so many leading authorities contribute their expertise and insight into this work. In the following chapters, the reader will find insight and guidance that will enhance scholarship, as well as patient care.

Managing thrombosis in cancer patients

Venous thromboembolism is a major complication in cancer patients. The basis for the strong association between cancer and thrombosis remains incompletely understood, and the optimal approaches to both the treatment and the prevention of cancer-associated thrombosis are evolving. Here we review several important topics related to cancer-associated thromboembolism, including the pathogenesis, prevention, and management of this disease. Wherever possible, we include evidence from clinical trials, including the results of recently published trials that compared direct oral anticoagulants to low-molecular-weight heparin for the treatment of cancer-associated thrombosis.

A single center retrospective cohort study comparing low-molecular-weight heparins to direct oral anticoagulants for the treatment of venous thromboembolism in patients with cancer - A real world experience

INTRODUCTION

Low-molecular-weight heparins are the standard treatment for cancer-associated thrombosis. Recently, direct oral anticoagulants are a new option for thrombosis treatment; however, data supporting the use of direct oral anticoagulants for cancer-associated thrombosis are limited.

OBJECTIVES

The primary objective of this study was to determine the rate of recurrent cancer-associated thrombosis and major bleeding within 6 months of starting either low-molecular-weight heparin or direct oral anticoagulant for treatment of cancer-associated thrombosis. Secondary objectives were to determine the rates of clinically relevant-non-major bleeding and all-cause mortality.

PATIENTS/METHODS

This is a retrospective cohort study including adults with cancer-associated thrombosis treated with low-molecular-weight heparin or direct oral anticoagulant between 2010 and 2016 at the Ohio State University. Medical records were reviewed for 6 months after initiation of anticoagulation or until the occurrence of recurrent cancer-associated thrombosis, major bleeding, cessation of anticoagulation of interest, or death, whichever occurred first.

RESULTS

Four hundred and eighty patients were included (290 low-molecular-weight heparin and 190 direct oral anticoagulant). Patients treated with direct oral anticoagulant were found to carry "lower risk" features including cancer with lower VTE risk and lower rate of metastatic disease. After adjustment for baseline differences, there was no significant difference in the rate of recurrent cancer-associated thrombosis (7.2% low-molecular-weight heparin vs 6.3% direct oral anticoagulant, p = 0.71) or major bleeding (7.6% low-molecular-weight heparin vs 2.6% direct oral anticoagulant, p = 0.08).

CONCLUSIONS

Our study demonstrates that in a select population of cancer patients with VTE, direct oral anticoagulant use can be as effective and safe compared to the standard therapy with low-molecular-weight heparin.

Single-center, retrospective evaluation of safety and efficacy of direct oral anticoagulants versus low-molecular-weight heparin and vitamin K antagonist in patients with cancer

INTRODUCTION

The safety and efficacy of direct oral anticoagulants in cancer patients is currently unclear. Low-molecular-weight heparin remains the standard of care for cancer patients with venous thromboembolism, with warfarin, a vitamin K antagonist, as an alternative. Clear recommendations do not exist for patients with both active cancer and non-valvular atrial fibrillation. The objectives of this study were to report safety and efficacy outcomes of direct oral anticoagulants, low-molecular-weight heparin, and vitamin K antagonist in cancer patients with venous thromboembolism or non-valvular atrial fibrillation.

METHODS

Retrospective chart review of adult cancer patients from 2012 to 2015 who received an antineoplastic agent and an anticoagulant.

RESULTS

A total of 258 patients were reviewed: 80 patients in direct oral anticoagulant group, 95 patients in low-molecular-weight heparin group, and 83 patients in vitamin K antagonist group. Sixty-seven percent of patients were on an anticoagulant for acute or chronic venous thromboembolism. Major bleeding events were similar across the groups (15% direct oral anticoagulant vs 17% low-molecular-weight heparin vs 18% vitamin K antagonist). The most common type of major bleeding event was gastrointestinal bleeding. A total of five fatal bleeding events occurred. Venous thromboembolism recurrence rates were higher in both direct oral anticoagulant (18%) and low-molecular-weight heparin (12%) groups while lower in vitamin K antagonist group (10%) compared to previous studies.

CONCLUSIONS

Cancer patients receiving direct oral anticoagulants, low-molecular-weight heparin, or vitamin K antagonist had similar rates of major bleeding events, with gastrointestinal bleeding being the most common event. Venous thromboembolism recurrence rates were higher in direct oral anticoagulant and low-molecular-weight heparin groups than prior studies. Randomized trials are warranted to establish clear safety and efficacy in this population.