Cost-utility analysis of apixaban compared with usual care for primary thromboprophylaxis in ambulatory patients with cancer

Preventative and curative treatment of venous thromboembolic disease in cancer patients

Cancer-associated venous thromboembolism (CAT) is common in patients with cancer and associated with significant morbidity and mortality. The incidence of CAT continues to rise, complicating patient care and burdening healthcare systems. Patients with cancer experiencing VTE face poorer prognoses, making prevention and effective management imperative. This narrative review synthesizes evidence on thromboprophylaxis in ambulatory patients with cancer receiving systemic therapy and acute treatment strategies for CAT. Risk assessment models (e.g., Khorana score) aid in identifying high-risk patients who may benefit from thromboprophylaxis. Pharmacological thromboprophylaxis with low molecular weight heparins (LMWHs) and direct oral anticoagulants (DOACs) has been shown to reduce the risk of CAT without significantly increasing the risk of bleeding complications. However, implementation of risk-based strategies remains limited in clinical practice. For acute CAT management, LMWHs have been the standard of care, but DOACs are increasingly favored due to their convenience and efficacy. However, challenges persist, including bleeding risks and drug interactions. Emerging therapies targeting Factor XI inhibitors present promising alternatives, potentially addressing current limitations in anticoagulation management for CAT.

Direct oral anticoagulants versus low-molecular-weight heparin in patients with cancer-associated venous thrombosis: a cost-effectiveness analysis

Background

Direct oral anticoagulants (DOACs) have demonstrated clinical benefits and better patient adherence over low-molecular-weight heparin (LMWH) in treating patients with cancer-associated venous thrombosis (CAT). We aimed to compare the cost-effectiveness of DOACs against LMWH in patients with CAT from the perspective of the Hong Kong healthcare system.

Methods

A Markov state-transition model was performed to estimate the incremental cost-effectiveness ratio (ICER) per quality-adjusted life years (QALYs) for DOACs and LMWH in a hypothetical cohort of 10,000 patients with CAT over a 5-year lifetime horizon. The model was primarily based on the health states of no event, recurrent venous thromboembolism, bleeding, and death. Transition probabilities, relative risks, and utilities were derived from the literature. Resource cost data were obtained from the Hong Kong Hospital Authority. Deterministic and probabilistic sensitivity analyses tested the robustness of the results.

Results

Relative to LMWH, DOACs were associated with increased QALYs (1.52 versus 1.50) at a lower medical cost of USD 2,232 versus 8,224 in five years. The cost of LMWH was the main contributor to the outcome. Out of 10,000 simulated cases, DOACs were dominant in 15.8% and cost-effective in 42.1%, at the willingness-to-pay threshold of USD 148,392 per additional QALY.

Conclusions

DOACs were associated with greater QALY improvements and lower overall costs compared to LMWH. Accounting for uncertainty, DOACs were between cost-effective and dominant in 57.9% of cases. DOACs are a cost-effective alternative to LMWH in the management of CAT in Hong Kong.

Arterial Thrombosis in Patients with Cancer

Patients with cancer are at increased risk of arterial thromboembolic disease due to the presence of risk factors common to both the development of cancer and arterial thrombosis, the cancer itself, and the treatments provided to treat cancer. We review here the epidemiology and pathophysiology of arterial thromboembolic disease in cancer, along with its prevention and treatment strategies. We also propose a generalized approach for the management of arterial thromboembolic disease in this patient population.

Cancer-Associated Thrombosis: Epidemiology, Pathophysiological Mechanisms, Treatment, and Risk Assessment

Cancer patients represent a growing population with drastically difficult care and a lowered quality of life, especially due to the heightened risk of vast complications. Thus, it is well established so far that one of the most prominent complications in individuals with cancer is venous thromboembolism. Since there are various improved methods for screening and diagnosing cancer and its complications, the incidence of cancer-associated thrombosis has been on the rise in recent years. Therefore, the high mortality and morbidity rates among these patients are not a surprise. Consequently, there is an excruciating need for understanding the mechanisms behind this complex process, as well as the imperative for adequate analysis and application of the most suitable steps for cancer-associated thrombosis prevention. There are various and numerous mechanisms offering potential answers to cancer-associated thrombosis, some of which have already been elucidated in various preclinical and clinical scenarios, yet further and more elaborate studies are crucial to understanding and preventing this complex and harsh clinical entity. This article elaborates on the growing incidence, mortality, morbidity, and risk factors of cancer-associated thrombosis while emphasizing the pathophysiological mechanisms in the light of various types of cancer in patients and summarizes the most novel therapy and prevention guidelines recommendations.

Anticoagulation for the Prevention of Arterial Thrombosis in Ambulatory Cancer Patients: Systematic Review and Meta-Analysis

Background

The risk of arterial thrombotic events (ATEs) is high among patients on systemic anticancer therapies. Despite the efficacy of anticoagulants in the prevention of cancer-associated venous thromboembolism, it is unknown whether anticoagulation is effective to prevent ATEs.

Objectives

This study sought to examine the efficacy and safety of anticoagulants in ATE prevention among ambulatory cancer patients.

Methods

We performed a systematic review using Medline, Embase, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) from inception to May 21, 2022, and included studies comparing oral or parenteral anticoagulation with no anticoagulation among ambulatory patients receiving systemic anticancer therapy with no other indication for anticoagulation. The primary outcome was ATE (myocardial infarction, ischemic stroke, intra-abdominal arterial embolism, or peripheral artery occlusion). The secondary outcomes were major and nonmajor bleeding and all-cause mortality.

Results

Fourteen randomized trials involving low-molecular-weight heparins, direct oral anticoagulants, and warfarin were included. ATEs were captured as coefficacy endpoints or adverse events. Anticoagulant use was not associated with a reduction in ATEs compared with placebo or standard treatment (RR: 0.73, 95% CI: 0.50-1.04; P = 0.08; I2 = 0%). RRs of major and minor bleeding were 1.56 (95% CI: 1.12-2.17) and 2.25 (95% CI: 1.45-3.48) with anticoagulant use. In 13 trials that reported all-cause mortality, risk of death was not reduced with anticoagulants (RR: 0.99; 95% CI: 0.95-1.02; P = 0.38; I2 = 0%).

Conclusions

Anticoagulants did not reduce ATE risk among ambulatory patients on systemic anticancer therapy and were associated with increased bleeding. Based on the current data, anticoagulants have a limited role in ATE prevention in this population as a whole.

Indefinite Anticoagulant Therapy for First Unprovoked Venous Thromboembolism : A Cost-Effectiveness Study

BACKGROUND

Clinical practice guidelines recommend indefinite anticoagulation for a first unprovoked venous thromboembolism (VTE).

OBJECTIVE

To estimate the benefit-harm tradeoffs of indefinite anticoagulation in patients with a first unprovoked VTE.

DESIGN

Markov modeling study.

DATA SOURCES

Systematic reviews and meta-analyses for the long-term risks and case-fatality rates of recurrent VTE and major bleeding. Published literature for costs, quality of life, and other clinical events.

TARGET POPULATION

Patients with a first unprovoked VTE who have completed 3 to 6 months of initial anticoagulant treatment.

TIME HORIZON

Lifetime.

PERSPECTIVE

Canadian health care public payer.

INTERVENTION

Indefinite anticoagulation with direct oral anticoagulants.

OUTCOME MEASURES

Recurrent VTE events, major bleeding events, costs in 2022 Canadian dollars (CAD), and quality-adjusted life-years (QALYs).

RESULTS OF BASE-CASE ANALYSIS

When compared with discontinuing anticoagulation after initial treatment in a hypothetical cohort of 1000 patients aged 55 years, indefinite anticoagulation prevented 368 recurrent VTE events, which included 14 fatal pulmonary emboli, but induced an additional 114 major bleeding events, which included 30 intracranial hemorrhages and 11 deaths from bleeding. Indefinite anticoagulation cost CAD $16 014 more per person and did not increase QALYs (-0.075 per person).

RESULTS OF SENSITIVITY ANALYSIS

Model results were most sensitive to the case-fatality rate of major bleeding and the annual risk for major bleeding during extended anticoagulation.

LIMITATION

The model assumed that risks for recurrent VTE and major bleeding measured in clinical trials at 1 year remained constant during extended anticoagulation.

CONCLUSION

Clinicians should use shared decision making to incorporate individual patient preferences and values when considering treatment duration for unprovoked VTE.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research.

Cost-effectiveness of apixaban and rivaroxaban in thromboprophylaxis of cancer patients treated with chemotherapy in Spain

BACKGROUND

Apixaban and rivaroxaban are two direct-acting oral anticoagulants (DOACs) recommended for thromboprophylaxis in cancer patients treated with chemotherapy in an ambulatory setting. We aimed to assess the cost-utility of thromboprophylaxis with apixaban and rivaroxaban vs no thromboprophylaxis in ambulatory cancer patients starting chemotherapy with an intermediate-to-high risk of venous thromboembolism (VTE), Khorana score ≥ 2 points.

METHODS

A cost-effectiveness analysis was performed from the perspective of Spain's National Health System (NHS) using an analytical decision model in the short-term (180 days) and a Markov model in the long-term (5 years). Transition probabilities were obtained from randomized, double-blind, placebo-controlled clinical trials of apixaban and rivaroxaban in adult ambulatory patients with cancer at risk for VTE, treated with chemotherapy (AVERT and CASSINI trials). The costs (€2,021) were taken from Spanish sources. The utilities of the model were obtained through the EQ-5D questionnaire. Deterministic (base case) and probabilistic (second-order Monte Carlo simulation) analyses were conducted.

RESULTS

In the probabilistic sensitivity analysis, apixaban generated a cost per patient of €1,082 ± 187, with a 95% confidence interval (CI) of €713-1,442, while no prophylaxis produced a cost per patient of €1,146 ± 218, with a 95% CI of €700-1,491, with a saving of €64 per patient and a gain of 0.008 QALYs. Likewise, rivaroxaban provided a cost per patient of €993 ± 133, with a 95% CI of €748-1,310, while no prophylaxis produced a cost per patient of €872 ± 152, with a 95% CI of €602-1,250, with an additional expense of €121 per patient and a gain of 0.008 QALYs.

CONCLUSIONS

In thromboprophylaxis of cancer patients, the use of apixaban and rivaroxaban generated similar costs compared to non-prophylaxis, without the difference found being statistically significant, with a clinically insignificant QALY gain.

Venous thromboembolism risk in patients receiving neoadjuvant chemotherapy for bladder cancer

INTRODUCTION

There is limited evidence to inform thromboprophylaxis use for patients receiving neoadjuvant chemotherapy prior to surgery in bladder cancer. We sought to determine the incidence of venous thromboembolism (VTE) in patients receiving neoadjuvant chemotherapy and cystectomy. We also assessed if the Khorana score was associated with VTE risk.

METHODS

A retrospective cohort study was performed on consecutive patients who received a radical cystectomy for bladder cancer at The Ottawa Hospital between January 2016 and August 2020. Demographic information, chemotherapy data, operative characteristics, VTE and bleeding outcomes were collected from the start of treatment to 90 days postoperative. A Khorana score was calculated for each patient who received neoadjuvant chemotherapy. The primary outcome for this study was the incidence of VTE from the time the patient started treatment with neoadjuvant chemotherapy until 90 days post-cystectomy. Secondary outcomes included risk factors for VTE during neoadjuvant chemotherapy.

RESULTS

Among 181 radical cystectomy cases during the study period, 123 had muscle-invasive disease and 72 (39.8%) received neoadjuvant chemotherapy. Eighteen (25.0%) patients who received neoadjuvant chemotherapy and radical cystectomy developed a VTE from the start of chemotherapy to 90 days postoperative. Thirteen of the 18 VTEs (72%) occurred while the patient was receiving chemotherapy. In multivariable analysis, the only factor associated with a significantly increased risk of VTE was treatment with neoadjuvant chemotherapy (Relative risk (RR) 3.05, 95% confidence interval [CI] 1.16-8.02; P = 0.02). A higher Khorana score was not associated with an increased risk of VTE in patients who received neoadjuvant chemotherapy (RR = 0.33, 95% CI 0.08-1.28, P = 0.11). One (1.4%) patient had a major bleeding event during neoadjuvant chemotherapy.

CONCLUSIONS

Patients receiving neoadjuvant chemotherapy and radical cystectomy are at very high-risk of VTE. Prospective studies that assess the benefits and harms of pharmacologic thromboprophylaxis in this population are needed.