Treatment of venous thromboembolism in cancer patients: a systematic review and meta-analysis on the efficacy and safety of different direct oral anticoagulants (DOACs)

Comparison of rivaroxaban and low molecular weight heparin in the treatment of cancer-associated venous thromboembolism: a Swedish national population-based register study

BACKGROUND

Treating cancer-associated venous thromboembolism (CAT) with anticoagulation prevents recurrent venous thromboembolism (rVTE), but increases bleeding risk.

OBJECTIVES

To compare incidence of rVTE, major bleeding, and all-cause mortality for rivaroxaban versus low molecular weight heparin (LMWH) in patients with CAT.

METHODS

We developed a cohort study using Swedish national registers 2013-2019. Patients with CAT (venous thromboembolism within 6 months of cancer diagnosis) were included. Those with other indications or with high bleeding risk cancers were excluded (according to guidelines). Follow-up was from index-CAT until outcome, death, emigration, or end of study. Incidence rates (IR) per 1000 person-years with 95% confidence interval (CI) and propensity score overlap-weighted hazard ratios (HRs) for rivaroxaban versus LMWH were estimated.

RESULTS

We included 283 patients on rivaroxaban and 5181 on LMWH. The IR for rVTE was 68.7 (95% CI 40.0-109.9) for rivaroxaban, compared with 91.6 (95% CI 81.9-102.0) for LMWH, with adjusted HR 0.77 (95% CI 0.43-1.35). The IR for major bleeding was 23.5 (95% CI 8.6-51.1) for rivaroxaban versus 49.2 (95% CI 42.3-56.9) for LMWH, with adjusted HR 0.62 (95% CI 0.26-1.49). The IR for all-cause mortality was 146.8 (95% CI 103.9-201.5) for rivaroxaban and 565.6 (95% CI 541.8-590.2) for LMWH with adjusted HR 0.48 (95% CI 0.34-0.67).

CONCLUSIONS

Rivaroxaban performed similarly to LMWH for patients with CAT for rVTE and major bleeding. An all-cause mortality benefit was observed for rivaroxaban which potentially may be attributed to residual confounding.

TRIAL REGISTRATION NUMBER

NCT05150938 (Registered 9 December 2021).

Efficacy and Safety of Apixaban versus Dalteparin as a Treatment for Cancer-Associated Venous Thromboembolism: A Systematic Review and Meta-Analysis

Background and Objectives: Venous thromboembolism (VTE) is common in cancer patients. Anticoagulant therapy with low-molecular-weight heparins (LMWHs) and direct oral anticoagulants (DOACs), such as dalteparin and apixaban, have demonstrated efficacy and safety. However, more comparative research of these drugs is still needed. This study aimed to synthesize evidence on the efficacy of apixaban compared to dalteparin in reducing recurrent VTE, major bleeding, and clinically relevant non-major bleeding associated with cancer. Materials and Methods: We systematically searched the PubMed, Scopus, Web of Science, Embase, Cochrane Library, and ClinicalTrials databases up to 5 January 2023, for randomized controlled trials comparing apixaban versus dalteparin as treatment for cancer-associated VTE. Five studies were included. Effects according to meta-analyses were reported as relative risks (RRs) and their 95% confidence intervals (CIs). Results: It was found that 33 of 734 (4.5%) patients treated with apixaban and 56 of 767 (7.3%) with dalteparin had recurrent VTE as the efficacy outcome (RR 0.49, 95% CI 0.15-1.58, I2 38%). Major bleeding occurred in 25 of 734 patients treated with apixaban (3.4%) and 27 of 767 with dalteparin (3.5%) (RR 1.29, 95% CI 0.31-5.27, I2 59%). Likewise, clinically relevant non-major bleeding occurred in 64 of 734 patients treated with apixaban (8.7%) and 46 of 767 (5.9%) with dalteparin (RR 1.52, 95% CI 1.05-2.19, I2 0%). Conclusions: Apixaban showed a lower risk of recurrent VTE than dalteparin in patients with cancer-associated VTE, albeit with no statistical difference. Statistical significance was observed for no major clinically relevant bleeding but not for major bleeding.

Oral direct thrombin inhibitors or oral factor Xa inhibitors versus conventional anticoagulants for the treatment of pulmonary embolism

BACKGROUND

Pulmonary embolism (PE) is a potentially life-threatening condition in which a clot can migrate from the deep veins, most commonly in the leg, to the lungs. Conventional treatment of PE used unfractionated heparin (UFH), low molecular weight heparin (LMWH), fondaparinux, and vitamin K antagonists (VKAs). Recently, two forms of direct oral anticoagulants (DOACs) have been developed: oral direct thrombin inhibitors (DTIs) and oral factor Xa inhibitors. DOACs have characteristics that may be favourable to conventional treatment, including oral administration, a predictable effect, no need for frequent monitoring or re-dosing, and few known drug interactions. This review reports the efficacy and safety of these drugs in the long-term treatment of PE (minimum duration of three months). This is an update of a Cochrane Review first published in 2015.  OBJECTIVES: To assess the efficacy and safety of oral DTIs and oral factor Xa inhibitors versus conventional anticoagulants for the long-term treatment of PE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases, the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trials registers to 2 March 2022. We checked the reference lists of relevant articles for additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in which people with a PE confirmed by standard imaging techniques were allocated to receive an oral DTI or an oral factor Xa inhibitor compared with a conventional anticoagulant or compared with each other for the long-term treatment of PE (minimum duration three months).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were recurrent PE, recurrent venous thromboembolism (VTE), and deep vein thrombosis (DVT). Secondary outcomes were all-cause mortality, major bleeding, and health-related quality of life. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified five additional RCTs with 1484 participants for this update. Together with the previously included trials, we have included ten RCTs with a total of 13,073 participants. Two studies investigated an oral DTI (dabigatran) and eight studies investigated oral factor Xa inhibitors (three rivaroxaban, three apixaban, and two edoxaban). The studies were of good methodological quality overall.  Meta-analysis showed no clear difference in the efficacy and safety of oral DTI compared with conventional anticoagulation in preventing recurrent PE (odds ratio (OR) 1.02, 95% confidence interval (CI) 0.50 to 2.04; 2 studies, 1602 participants; moderate-certainty evidence), recurrent VTE (OR 0.93, 95% CI 0.52 to 1.66; 2 studies, 1602 participants; moderate-certainty evidence), DVT (OR 0.79, 95% CI 0.29 to 2.13; 2 studies, 1602 participants; moderate-certainty evidence), and major bleeding (OR 0.50, 95% CI 0.15 to 1.68; 2 studies, 1527 participants; moderate-certainty evidence). We downgraded the certainty of evidence by one level for imprecision due to the low number of events. There was also no clear difference between the oral factor Xa inhibitors and conventional anticoagulation in the prevention of recurrent PE (OR 0.92, 95% CI 0.66 to 1.29; 3 studies, 8186 participants; moderate-certainty evidence), recurrent VTE (OR 0.83, 95% CI 0.66 to 1.03; 8 studies, 11,416 participants; moderate-certainty evidence), DVT (OR 0.77, 95% CI 0.48 to 1.25; 2 studies, 8151 participants; moderate-certainty evidence), all-cause mortality (OR 1.16, 95% CI 0.79 to 1.70; 1 study, 4817 participants; moderate-certainty evidence) and major bleeding (OR 0.71, 95% CI 0.36 to 1.41; 8 studies, 11,447 participants; low-certainty evidence); the heterogeneity for major bleeding was significant (I2 = 79%). We downgraded the certainty of the evidence to moderate and low because of imprecision due to the low number of events and inconsistency due to clinical heterogeneity. None of the included studies measured health-related quality of life.

AUTHORS' CONCLUSIONS

Available evidence shows there is probably little or no difference between DOACs and conventional anticoagulation in the prevention of recurrent PE, recurrent VTE, DVT, all-cause mortality, and major bleeding. The certainty of evidence was moderate or low. Future large clinical trials are required to identify if individual drugs differ in effectiveness and bleeding risk, and to explore effect differences in subgroups, including people with cancer and obesity.

Direct oral anticoagulants for venous thromboembolism in cancer patients: a systematic review and network meta-analysis

BACKGROUND

The efficacy and safety of direct oral anticoagulants (DOACs), including dabigatran, apixaban, rivaroxaban, and edoxaban, for preventing and treating venous thromboembolism (VTE) in patients with cancer is unclear.

METHODS

We searched the PubMed, Embase, Web of Science, and Cochrane Library databases from the establishment to November 30, 2021. In the frequency-based network meta-analysis, the odds ratio with a 95% confidence interval was reported. The relative ranking probability of each group was generated based on the surface under the cumulative ranking curve (SUCRA).

RESULTS

We included 15 randomized controlled trials involving a total of 6162 patients. Apixaban reduced the risk of VTE compared with low-molecular heparin [OR = 0.53, 95% CI (0.32, 0.89)]. The efficacy of drugs was ranked from highest to lowest as follows: apixaban (SUCRA, 81.0), rivaroxaban (73.0), edoxaban (65.9), dabigatran (51.4), warfarin (30.8), and low-molecular-weight heparin (LMWH) (27.4). Edoxaban increased the risk of major bleeding compared with LMWH [OR = 1.83, 95% CI (1.04, 3.22)]. The safety of drugs was ranked from highest to lowest as follows: major bleeding-apixaban (SUCRA, 68.5), LMWH (55.1), rivaroxaban (53.0), warfarin (35.9), dabigatran (29.2), edoxaban (16.5) and clinically relevant non-major bleeding-LMWH (73.0), apixaban (57.8), edoxaban (45.8), rivaroxaban (35.3), and warfarin (10.8).

CONCLUSIONS

For preventing and treating VTE, in terms of VTE occurrence and major bleeding, apixaban had the lowest risk; in terms of clinically relevant non-major bleeding, LMWH had the lowest risk, followed by apixaban. Generally, apixaban is the most efficient and safest DOAC and presents better efficacy and relatively low bleeding risk among the VTE prevention and treatment drugs for patients with cancer.

DOACs or VKAs or LMWH – What is the optimal regimen for cancer-associated venous thromboembolism? A systematic review and meta-analysis

Background

Clinical guidelines have supported the use of direct anticoagulants (DOACs) for the treatment of cancer-associated venous thromboembolism (Ca-VTE). However, recent trials have reported increased bleeding risks associated with DOACs usage, raising concerns regarding its efficacy.

Objectives

The authors conducted a meta-analysis to study the efficacy and safety of DOACs for the treatment of VTE in cancer patients, compared with Low-weight molecular heparin (LMWH) and Vitamin-K antagonists (VKAs).

Methods

PubMed, EMBASE, Cochrane Library, Cochrane Central Register of Controlled Trials (CENTRAL) were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines from inception to June 17th, 2021.The primary outcomes studied were VTE recurrence and major bleeding.

Results

A total of 8 randomized controlled trials (RCTs) enrolling almost 7000 patients were included. Direct oral anticoagulants significantly reduced VTE Recurrence in cancer patients when compared to patients treated with LMWH or VKAs (Hazard ratio [HR] 0.62, 95% confidence interval [CI] 0.46–0.83; P = 0.002; I² = 26%). There were no statistically significant differences for major bleeding (HR 0.86, 95% confidence interval [CI] 0.56–1.33; P = 0.50; I² = 34%), clinically relevant non-major bleeding (HR 1.23, 95% confidence interval [CI] 0.79–1.91; P = 0.35; I² = 66%), pulmonary embolism (HR 0.71, 95% confidence interval [CI] 0.47–1.06; P = 0.10; I² = 7%), and all-cause mortality (HR 0.98, 95% confidence interval [CI] 0.86–1.12; P = 0.78; I² = 1%), between DOACs and LMWH.

Conclusion

This analysis shows that DOACs are the optimal regimen to treat Ca-VTE. They have a similar to slightly increased bleeding risk compared with LMWH and are a safer alternative to VKAs.

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Patients receiving DOACs show a significant decrease for VTE recurrence.

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Rivaroxaban pertaining to the most effective DOAC.

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Edoxaban proving to be more useful in reducing bleeding risk more than LMWHs.

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Further research is needed to investigate the correlation between cancer types and the efficacy of DOACs in treating Ca-VTE.

Risks, diagnosis, and management of recurrent cancer-associated thrombosis (CAT): a narrative review

This paper aims to provide a narrative review of the risks, diagnosis, and management of recurrent venous thromboembolism (VTE) in cancer patients. There is an established association between cancer and VTE, with cancer being a major risk factor for VTE. A history of VTE, short duration of oral anticoagulation, and a proximal DVT are all associated with increased risk for recurrent VTE. Studies have shown that certain cancers (e.g., metastatic genitourinary, lung, and colorectal cancers) are associated with recurrent VTE. Published literature shows that cancer is prothrombotic, and various mechanisms have been postulated as pathways for increased thrombogenesis and hence recurrent VTE in cancer. The symptoms, signs, laboratory information, and imaging results for the diagnosis of recurrent VTE are similar to those of an initial VTE. Management of recurrent VTE involves using low molecular weight heparin (LMWH) or a direct oral anticoagulant (DOAC). Vitamin K antagonists (VKA) or inferior vena cava (IVC) filters are less commonly used.