Direct Oral Anticoagulants in the Prevention and Treatment of Venous Thromboembolism in Patients with Cancer: New Insights from Randomized Controlled Trials

Direct oral anticoagulants for the treatment and prevention of venous thromboembolism in patients with cancer: current evidence

Venous thromboembolic disease (VTED) is a common and clinically important complication in patients with cancer, contributing to its mortality and morbidity. Direct oral anticoagulant agents (DOACs), including direct thrombin inhibitors and direct factor Xa inhibitors, are as effective as vitamin K antagonists for the treatment of VTED and are associated with less frequent and severe bleeding. They have advantages over low-molecular-weight heparin, but comparative long-term efficacy and safety data are lacking for these compounds. Recent randomized clinical trials suggest a role for DOACs in the treatment of VTED in patients with cancer. This review will discuss the existing evidence and future perspectives on the role of DOACs in the treatment of VTE based on the current evidence about their overall efficacy and safety and the limited information in patients with cancer; in addition, we will briefly review their pharmacokinetic properties with special reference to potential interactions.

Direct oral anticoagulant versus low-molecular-weight heparin for treatment of venous thromboembolism in cancer patients: An updated meta-analysis of randomized controlled trials

BACKGROUND

Cancer associated venous thromboembolism (VTE) results in significant morbidity and mortality. Low molecular weight heparin (LMWH) has been standard of care for treatment of cancer-associated VTE, however direct oral anticoagulants (DOACs) are emerging as alternative treatment options.

OBJECTIVE

To compare the benefits and harms of DOACs versus LMWH for treatment of VTE in cancer.

DATA SOURCES

MEDLINE, Embase, and the Cochrane Collaboration Central Register of Controlled Trials from inception to April 2020.

STUDY SELECTION

Randomized controlled trials (RCT) comparing DOACs with LMWH for treatment of VTE in cancer patients.

DATA SYNTHESIS

Four good-quality RCTs, met inclusion criteria. Compared with LMWH, DOACs were associated with lower rates of VTE recurrence (RR 0.62; 95% CI: 0.44-0.87; P = 0.006), and DVT recurrence (RR 0.61; 95% CI: 0.4-0.94; P = 0.02) but not PE recurrence (RR 0.73; 95% CI: 0.51-1.04; P = 0.08), in cancer patients. However, the risk of clinically relevant non-major bleeding (CRNMB) (RR 1.58; 95% CI: 1.11-2.24; P = 0.01), and major bleeding in gastrointestinal cancer (RR 2.55; 95% CI 1.24-5.27, P = 0.01), were higher with DOACs. The risk of overall major bleeding (RR 1.33; 95% CI: 0.84-2.1; P = 0.22), all-cause mortality (RR 0.99; 95% CI: 0.84-1.17; P = 0.92), VTE-related mortality (RR: 1; 95% CI: 0.29-3.44; P = 1) and bleeding-related mortality (RR: 0.71; 95% CI: 0.17-2.91; P = 0.63), were similar in both treatment groups.

CONCLUSION

Among cancer patients with VTE, treatment with DOACs is associated with a significant reduction of VTE and DVT recurrence, compared to LMWH. These benefits were offset by an increased risk of CRNMB, and major bleeding in gastrointestinal cancer.

Use of New Oral Anticoagulants / Direct Oral Anticoagulants in Malignant Patients

Vitamin K antagonists are being used in the last five decades as an effective anticoagulant. However, for the past few years, new oral anticoagulants (NOACs) have been introduced as newer anticoagulant agents, which are gradually replacing the previously used vitamin K antagonist. Yet, these agents have not fully replaced the use of warfarin and heparin. NOACs have few advantages over the vitamin K antagonist as they act on a specific factor of coagulation cascade rather than inhibiting the whole vitamin K synthesis. In this article, all the data has been searched electronically on PubMed and PRISMA guidelines were not followed. Instead, we used MOOSE statements and the data searched on PubMed was from articles published in the last five years. A total of 12,269 patients were observed;,out of which 64.19% had active cancer and 35.80% was observed as a control group comprised of both male or female participants. Approximately 61.14% were using NOACs, 42.83% were on warfarin, and 2.72% were on low-molecular-weight heparin (LMWH). The NOACs used in different patients were in the following percentages; edoxaban (6.81%), apixaban (5.28%), dabigatran (10.09%), and rivaroxaban (10.02%). The use of NOACs has been increasing day by day but these agents have not completely replaced the warfarin or heparin, because of some demerits associated with the use of warfarin and some conditions where these drugs should be avoided. All NOACs have either hepatic or renal clearance so the hepatic activity and creatinine clearance rate must be monitored before the start of NOACs. The drug interaction between anticancer drugs and NOACs is still not fully reported. The effects of NOACs in AF and VTE are therapeutically effective, but in oncology patients several other co-factors are also involved with the use of NOACs due to which, it is either contraindicated or in some cases dose adjustment is required. However, very little information has been collected and more investigation must be done in this perspective.