The efficacy and safety of DOACs versus LMWH for cancer-associated thrombosis: A systematic review and meta-analysis

The Role of Direct Oral Anticoagulants in the Treatment of Cancer-Associated Venous Thromboembolism: Review by Middle East and North African Experts

Venous thromboembolism is a leading cause of morbidity and mortality in patients with active cancer who require anticoagulation treatment. Choice of anticoagulant is based on careful balancing of the risks and benefits of available classes of treatment: vitamin K antagonists, low-molecular-weight heparin (LMWH), and direct oral anticoagulants (DOACs). Results from randomized controlled trials have shown the consistent efficacy of DOACs versus LMWH in the treatment of cancer-associated venous thromboembolism (VTE). However, increased major gastrointestinal bleeding was observed for edoxaban and rivaroxaban, but not apixaban, compared with LMWH dalteparin. Most guidelines recommend DOACs for the treatment of cancer-associated VTE in patients without gastrointestinal or genitourinary cancer, and with considerations for renal impairment and drug-drug interactions. These updates represent a major paradigm shift for clinicians in the Middle East and North Africa. The decision to prescribe a DOAC for a patient with cancer is not always straightforward, particularly in challenging subgroups of patients with an increased risk of bleeding. In patients with gastrointestinal malignancies who are at high risk of major gastrointestinal bleeds, apixaban may be the preferred DOAC; however, caution should be exercised if patients have upper or unresected lower gastrointestinal tumors. In patients with gastrointestinal malignancies and upper or unresected lower gastrointestinal tumors, LMWH may be preferred. Vitamin K antagonists should be used only when DOACs and LMWH are unavailable or unsuitable. In this review, we discuss the overall evidence for DOACs in the treatment of cancer-associated VTE and provide treatment suggestions for challenging subgroups of patients with cancer associated VTE.

Smart thrombosis inhibitors without bleeding side effects via charge tunable ligand design

Current treatments to prevent thrombosis, namely anticoagulants and platelets antagonists, remain complicated by the persistent risk of bleeding. Improved therapeutic strategies that diminish this risk would have a huge clinical impact. Antithrombotic agents that neutralize and inhibit polyphosphate (polyP) can be a powerful approach towards such a goal. Here, we report a design concept towards polyP inhibition, termed macromolecular polyanion inhibitors (MPI), with high binding affinity and specificity. Lead antithrombotic candidates are identified through a library screening of molecules which possess low charge density at physiological pH but which increase their charge upon binding to polyP, providing a smart way to enhance their activity and selectivity. The lead MPI candidates demonstrates antithrombotic activity in mouse models of thrombosis, does not give rise to bleeding, and is well tolerated in mice even at very high doses. The developed inhibitor is anticipated to open avenues in thrombosis prevention without bleeding risk, a challenge not addressed by current therapies.

Safe and effective treatment of venous Thromboembolism associated with Cancer: focus on direct Oral Anticoagulants in Asian patients

Cancer-associated thrombosis (CAT) poses a significant disease burden and the incidence in Asian populations is increasing. Anticoagulation is the cornerstone of treatment, but can be challenging due to the high bleeding risk in some cancers and the high risk of recurrent venous thromboembolism (VTE) in patients with malignancies. Direct oral anticoagulants (DOACs) are well established as first-choice treatments for VTE in non-cancer patients, offering a more convenient and less invasive treatment option than low-molecular-weight heparin (LMWH). Asian patients have exhibited comparable efficacy and safety outcomes with other races in trials of DOACs for VTE in the general population. Although no specific data are available in Asian patients with CAT, results from randomized controlled trials of apixaban, edoxaban, or rivaroxaban versus the LMWH, dalteparin, indicate that DOACs are a reasonable alternative to LMWH for anticoagulation in Asian patients with CAT. This is further supported by analyses of real-world data in Asian populations demonstrating the efficacy and safety of DOACs in Asian patients with CAT. Apixaban, edoxaban, or rivaroxaban are recommended in the most recently updated international guidelines as first-line therapy for CAT in patients without gastrointestinal or genitourinary cancers and at low risk of bleeding. An increased risk of major gastrointestinal bleeding was evident with edoxaban or rivaroxaban, but not apixaban, versus dalteparin in the clinical trials, suggesting that apixaban could be a safe alternative to LMWH in patients with gastrointestinal malignancies. Determining the optimal anticoagulant therapy for patients with CAT requires careful consideration of bleeding risk, tumor type, renal function, drug-drug interactions, financial costs, and patients' needs and preferences.

Incidence of venous thromboembolism in advanced lung cancer and efficacy and safety of direct oral anticoagulants: a multicenter, prospective, observational study (Rising-VTE/NEJ037 study)

Background:

Venous thromboembolism (VTE) is a well-known type of cancer-associated thrombosis and a common complication of malignancy. However, the incidence of VTE associated with lung cancer and the effectiveness of direct oral anticoagulants remain unclear. This study aimed to identify the incidence of VTE associated with lung cancer at the time of diagnosis or during treatment, the efficacy and safety of edoxaban, and associated risk factors.

Methods:

The Rising-VTE/NEJ037 study was a multicenter prospective observational study. Altogether, 1021 patients with lung cancer who were unsuitable for radical resection or radiation were enrolled and followed up for 2 years. Patients with VTE at the time of lung cancer diagnosis started treatment with edoxaban. The primary endpoint of this trial was the rate of newly diagnosed VTE after enrollment or recurrence rate 6 months after treatment initiation.

Results:

Data were available for 1008 patients. The median age was 70 years (range: 30–94 years), and 70.8% were men. Sixty-two patients had VTE at the time of lung cancer diagnosis, and 38 (9.9%) developed VTE at follow-up. No cases of VTE recurrence were recorded 6 months after treatment initiation with edoxaban. Major and clinically relevant non-major bleeding events occurred in 4.9% of patients and increased to 22.7% in the edoxaban treatment group.

Conclusions:

VTE occurrence should be monitored during lung cancer treatment. Although treatment with edoxaban was highly effective in preventing VTE recurrence, its administration should be cautiously considered because of the high bleeding rate.

Trial registration:

jRCTs061180025.

Direct oral anticoagulants versus low-molecular-weight heparins for the treatment of acute venous thromboembolism in patients with gastrointestinal cancer: a systematic review and meta-analysis

Background

The association between gastrointestinal (GI) cancer and a high incidence of venous thromboembolism (VTE) is well known. Previous randomized controlled studies demonstrated that direct oral anticoagulants (DOACs) effectively treat cancer-associated thrombosis (CAT). However, some DOACs appeared to increase the risk of bleeding, particularly in patients with GI malignancies. Therefore, the current systematic review and meta-analysis were conducted to evaluate the safety and efficacy of DOACs in GI cancer-associated thrombosis.

Methods

Two investigators individually reviewed all studies that compared DOACs and low-molecular-weight heparins (LMWHs) in GI cancer-associated thrombosis and were published in MEDLINE and EMBASE before February 2022. The effect estimates and 95% confidence intervals (CIs) from each eligible study were combined using the Mantel–Haenszel method.

Results

A total of 2226 patients were included in the meta-analysis. The rates of major bleeding in the DOAC and LMWH groups were not significantly different (relative risk [RR]: 1.31; 95% CI: 0.84–2.04; P = 0.23; I² = 41%). However, the rate of clinically relevant nonmajor bleeding (CRNMB) was significantly higher in the DOAC group (RR: 1.76; 95% CI: 1.24–2.52; P = 0.002; I² = 8%). The risks of recurrent VTE in the groups did not significantly differ (RR: 0.72; 95% CI: 0.49–1.04; P = 0.08; I² = 0%).

Conclusions

The current data suggest that treatment of GI cancer-associated thrombosis with DOACs significantly increases the risk of CRNMB. However, the risk of major bleeding was not significantly different. The efficacy of DOACs for preventing recurrent VTE in GI cancer was comparable to that of LMWHs.

Trial registration

INPLASY202180113.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00399-7.

Direct Oral Anticoagulants for the Treatment of Cancer-Associated Venous Thromboembolism: A Latin American Perspective

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality in patients with cancer. On the basis of results from randomized controlled trials, direct oral anticoagulants (DOACs) are now recommended for the treatment of cancer-associated VTE. The decision to use a DOAC requires consideration of bleeding risk, particularly in patients with gastrointestinal (GI) malignancies, the cost-benefit and convenience of oral therapy, and patient preference. While efficacy with apixaban, edoxaban, and rivaroxaban versus dalteparin has been consistent in the treatment of cancer-associated VTE, heterogeneity is evident with respect to major GI bleeding, with an increased risk with edoxaban and rivaroxaban but not apixaban. Although cost and accessibility vary in different countries of Latin America, DOACs should be considered for the long-term treatment of cancer-associated VTE in all patients who are likely to benefit. Apixaban may be the preferred DOAC in patients with GI malignancies and LMWH may be preferred for patients with upper or unresected lower GI tumors. Vitamin K antagonists should only be used for anticoagulation when DOACs and low molecular weight heparin are inaccessible or unsuitable.

An epidemic of redundant meta-analyses

BACKGROUND

Meta-analyses are widely used to strengthen available evidence and obtain more precise estimates of treatment effect than any individual trial. Paradoxically, multiplication of meta-analyses on the same topic can lead to confusion as practitioners no longer benefit from a rapid and synthetic response. This phenomenon may appear disproportionate when the number of published meta-analyses exceeds the number of original studies.

OBJECTIVES

To describe an example of redundant meta-analyses published in the same area with the same randomized clinical trials (RCTs).

METHODS

A systematic review was performed to identify all published meta-analyses of original RCTs that compared direct oral anticoagulants with low molecular weight heparins in cancer patients with venous thromboembolism (VTE). Forest plots were used to represent the meta-analyses results for efficacy (VTE recurrence) and safety (major bleeding) endpoints. An authors' network was constructed to explore the links between the authors of the published meta-analyses.

RESULTS

In the past 3 years, four original RCTs were the subject of 20 published meta-analyses by 142 authors: five, four, and 11 meta-analyses pooled the data of two, three, and four RCTs, respectively. The results of meta-analyses were similar regarding the risks of VTE recurrence and major bleeding. The 11 meta-analyses of four RCTs were published within 6 months of the publication of the last RCT.

CONCLUSIONS

The epidemic proportions of such redundant literature and authorship could be moderated by developing "living" meta-analyses and encouraging authors of new RCTs to update the corresponding meta-analysis in the same paper as their original research.