New orally active anticoagulant agents for the prevention and treatment of venous thromboembolism in cancer patients

Cost-effectiveness analysis and budget impact of rivaroxaban compared with dalteparin in patients with cancer at risk of recurrent venous thromboembolism

OBJECTIVES

In the 'Comparison of an Oral Factor Xa Inhibitor With Low Molecular Weight Heparin in Patients With Cancer With Venous Thromboembolism' (SELECT-D) trial, rivaroxaban showed relatively low venous thromboembolism (VTE) recurrence but higher bleeding compared with dalteparin in patients with cancer. We aim to calculate the cost-effectiveness and budget impact of rivaroxaban compared with dalteparin in patients with cancer at risk of recurrent VTE.

SETTING

We built a Markov model to calculate the cost-effectiveness from a societal perspective over a 5-year time horizon for the Dutch healthcare setting.

PARTICIPANTS

A hypothetical cohort of 1000 cancer patients with VTE entered the model with baseline characteristics based on the SELECT-D trial.

INTERVENTION

Six months of treatment with rivaroxaban (15 mg two times per day for first 3 weeks followed by 20 mg once daily) was compared with 6 months of treatment with dalteparin (200 IU/kg daily during month 1 followed by 150 IU/kg daily).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome of the cost-effectiveness analysis was the incremental cost-effectiveness ratio (ICER). The robustness of the model was evaluated in probabilistic and univariate sensitivity analyses. A budget impact analysis was performed to calculate the total annual financial consequences for a societal perspective in the Netherlands.

RESULTS

In the base case and all scenarios, rivaroxaban were cost-saving while also slightly improving the patient's health, resulting in economically dominant ICERs. In the probabilistic sensitivity analysis, 77.8% and 98.7% of the simulations showed rivaroxaban to be cost-saving and more effective for a 5-year and 6-month time horizon, respectively. Rivaroxaban can save up to €11 326 763 (CI €5 164 254 to €17 363 231) in approximately 8000 cancer patients with VTE per year compared with dalteparin based on a 1-year time horizon.

CONCLUSIONS

Treatment with rivaroxaban is economically dominant over dalteparin in patients with cancer at risk for recurrent VTE in the Netherlands. The use of rivaroxaban instead of dalteparin can save over €10 million per year, primarily driven by the difference in drug costs.

A retrospective analysis of risk factors associated with catheter-related thrombosis: a single-center study

BACKGROUND

Catheter-related thrombosis may lead to catheter infections and failure, further deep venous thrombosis, and pulmonary embolism. Recognizing the risk factors for catheter-related thrombosis is extremely important to inform the development of catheter care guidelines.

METHODS

Data were collected from a total of 1,532 patients who had undergone venous catheterization, including indwelling catheterization from 19 March 2019 to 30 March 2019 in the Sun Yat-sen Memorial Hospital. The factors for which data were to be collected included the patients' physical characteristics, catheter-related factors, and catheter care-related factors. Logistic regression analysis, the chi-squared test, Fisher's exact test, and the t-test were used to analyze the data.

RESULTS

Of the 1,532 patients studied, 28 developed intraductal thrombi, and of the factors analyzed, malignancy, a catheterization history, a history of thrombophilia, surgery during the week before catheterization, the catheterization duration, and anticoagulant therapy were significant risk factors associated with catheter-related thrombosis (all p < 0.05). There were no significant associations between the catheter brand, the number of lumens, the insertion direction, or the factors associated with catheter care and catheter-related thrombosis (all p > 0.05).

CONCLUSION

Our study incorporated clear and systematic risk factors associated with catheter-related thrombosis. Malignancy, history of thrombophilia, history of catheterization, surgery during the week before catheterization, and catheterization duration were associated with increased risks of catheter-related thrombosis. Prophylactic anticoagulation was effective for preventing and treating catheter-related thrombosis.

Thromboprophylaxis in the End-of-Life Cancer Care: The Update

Cancer patients are at increased risk for venous thromboembolism (VTE), which further increases with advanced stages of malignancy, prolonged immobilization, or prior history of thrombosis. To reduce VTE-related mortality, many official guidelines encourage the use of thromboprophylaxis (TPX) in cancer patients in certain situations, e.g., during chemotherapy or in the perioperative period. TPX in the end-of-life care, however, remains controversial. Most recommendations on VTE prophylaxis in cancer patients are based on the outcomes of clinical trials that excluded patients under palliative or hospice care. This translates to the paucity of official guidelines on TPX dedicated to this group of patients. The problem should not be underestimated as VTE is known to be associated with symptoms adversely impacting the quality of life (QoL), i.e., limb or chest pain, dyspnea, hemoptysis. In end-of-life care, where the assurance of the best possible QoL should be the highest priority, VTE prophylaxis may eliminate the symptom burden related to thrombosis. However, large randomized studies determining the benefits and risks profiles of TPX in patients nearing the end of life are lacking. This review summarized available data on TPX in this population, analyzed potential tools for VTE risk prediction in the view of this group of patients, and summarized the most current recommendations on TPX pertaining to terminal care.

Treatment of Cancer-Associated Thrombosis: Beyond HOKUSAI

Direct oral anticoagulants (DOACs) represent an attractive alternative to low-molecular-weight heparins (LMWHs) for the long-term treatment of cancer-associated thrombosis (CT) since they avoid the burden of daily injections. Analyses in subgroups of cancer patients from large randomized trials suggested that DOACs were at least as effective as vitamin K antagonists, while indirect comparisons suggested that DOACs' efficacy and safety profile were comparable to those of LMWHs. In the randomized controlled HOKUSAI-VTE Cancer study, currently the only completed phase III trial on DOACs in CT patients, edoxaban was shown noninferior to dalteparin on the composite primary endpoint of time to first recurrent venous thromboembolism or major bleeding during the 12 months after randomization. Study results suggest that both agents had comparable benefit/risk ratio in patients with CT. Even though this conclusion was valid from a strict statistical viewpoint, it was potentially misleading when interpreting benefit/risk ratios. Besides the obvious heterogeneity of the study population (e.g., 23% of patients no longer had cancer) and significantly different treatment durations between arms, secondary outcomes for efficacy were in favor of edoxaban for recurrent deep-vein thrombosis but not for recurrent pulmonary embolism, and major bleeding episodes were significantly more frequent in the edoxaban group, with an excess of gastrointestinal (GI) bleeding episodes observed mainly but not only in patients with GI cancers. More research is needed regarding specific patients' profiles, cancer types, and treatment period to better clarify the respective roles of DOACs and LMWHs in CT patients.

Efficacy and Safety of Direct Oral Anticoagulants for Risk of Cancer-Associated Venous Thromboembolism

Efficacy and safety of direct oral anticoagulants (DOACs) for preventing primary and recurrent venous thromboembolism (VTE) in patients with cancer remain unclear. In this study, we conducted a systematic review to summarize the most up-to-date evidence from randomized controlled trials (RCTs). Our primary outcomes included the benefit outcome (VTE) and safety outcome (major bleeding). A random-effects model was used to pool the relative risks (RRs) for data syntheses. The Grading of Recommendations Assessment, Development and Evaluation tool was used to evaluate the quality of the entire body of evidence across studies. We included 11 RCTs with a total of 3741 patients with cancer for analyses. The DOACs were significantly related with a reduced risk of VTE when compared with non-DOACs: RR = 0.77, 95% confidence interval [CI]: 0.61-0.99, P = .04. Nonsignificant trend towards a higher risk of major bleeding was found in DOACs: RR = 1.28 95% CI: 0.81-2.02, P = .29. The quality of the entire body of evidence was graded as moderate for risk of VTE, and low for risk of major bleeding. To summarize, DOACs were found to have a favorable effect on risk of VTE but a nonsignificant higher risk of major bleeding compared with non-DOACs in patients with cancer. The safety effect of DOACs in patients with cancer requires further evaluation in adequately powered and designed studies.

Duration of anticoagulant therapy and VTE recurrence in patients with cancer

Purpose

Anticoagulant therapy for at least 3–6 months is currently recommended for treatment of venous thromboembolism (VTE) in patients with cancer, but the optimal duration of treatment is unknown. This study examines the association between the duration of anticoagulation treatment and VTE recurrence in cancer patients.

Methods

The Humana claims database was used to identify newly diagnosed cancer patients who had their first VTE diagnosis between January 1, 2013, and May 31, 2015, and initiated injectable or oral anticoagulant therapy. Follow-up was calculated from the index treatment initiation to the end of eligibility or end of data (June 2015). VTE recurrence was defined as a hospitalization with a primary diagnosis of VTE. Cox proportional hazards models were used to evaluate the risk of VTE recurrence by duration of therapy in patients who discontinued therapy.

Results

The study included 1158 patients. Compared to patients treated for 0 to 3 months, VTE recurrences were significantly lower among patients treated for 3 to 6, or over 6 months. After adjustment for baseline characteristics, patients treated for 3 to 6 months (HR [95%CI], 0.53; 0.37–0.76) and more than 6 months (HR [95%CI], 0.48; 0.34–0.68) were still significantly less likely to have VTE recurrences compared to patients treated for 0 to 3 months (both p < 0.01). Findings were similar using a VTE event definition that included outpatient visits.

Conclusions

Among newly diagnosed cancer patients with VTE, anticoagulant therapy lasting more than 3 months was associated with a lower risk of VTE recurrence.

Electronic supplementary material

The online version of this article (10.1007/s00520-019-4661-3) contains supplementary material, which is available to authorized users.

Effectiveness and safety of anticoagulants for the treatment of venous thromboembolism in patients with cancer

Anticoagulation is used to treat venous thromboembolism (VTE) in cancer patients, but may be associated with an increased risk of bleeding. VTE recurrence and major bleeding were assessed in cancer patients treated for VTE with the most currently prescribed anticoagulants in clinical practice. Newly diagnosed cancer patients (first VTE 1/1/2013-05/31/2015) who initiated rivaroxaban, low-molecular-weight heparin (LMWH), or warfarin were identified from Humana claims data and observed until end of eligibility or end of data availability. VTE recurrence was a hospitalization with a primary diagnosis of VTE ≥7 days after first VTE. Major bleeding events on treatment were identified using validated criteria. Cohorts were compared using Kaplan-Meier rates at 6 and 12 months and Cox proportional hazards models. Cohorts were adjusted for their differences at baseline. A total of 2428 patients (rivaroxaban: 707; LMWH: 660; warfarin: 1061) met inclusion criteria. Patient characteristics were well balanced after weighting. There was a trend for lower VTE recurrence rates in rivaroxaban users compared to LMWH users at 6 months (13.2% vs. 17.1%; P = .060) and significantly lower at 12 months (16.5% vs. 22.2%; P = .030) [HR: 0.72, 95% CI: (0.52-0.95); P = .024]. VTE recurrence rates were also lower for rivaroxaban than warfarin users at 6 months (13.2% vs. 17.5%; P = .014) and 12 months (15.7% vs. 19.9%; P = .017) [HR: 0.74, 95% CI: (0.56-0.96); P = .028]. Major bleeding rates were similar across cohorts. This real-world analysis suggests cancer patients with VTE treated with rivaroxaban had significantly lower risk of recurrent VTE and similar risk of bleeding compared to those treated with LMWH or warfarin.

Rivaroxaban in the Treatment of PICC-associated Upper Extremity Venous Thrombosis

PURPOSE

Peripherally inserted central catheters (PICCs) are frequently used for prolonged drug administration, but their use is commonly complicated by the development of upper extremity deep venous thrombosis (UEDVT) requiring anticoagulation. Here, we compared the efficacy and safety profile of rivaroxaban (20 mg/d) with low molecular weight (LMW) heparin and vitamin K antagonists in the treatment of PICC-associated UEDVT.

METHODS

Patients (N = 84) with PICC-associated UEDVT were studied. All had UEDVT identified by ultrasound scanning. Further ultrasound images were obtained at 1, 2, and 3 months after the start of treatment. Forty-four patients were treated with rivaroxaban and 40 with initial LMW heparin and vitamin K antagonist with continuation of vitamin K antagonists alone once international normalized ratio was therapeutic FINDINGS: In the rivaroxaban group mean (SD) age was 51 (16) years and 57% were men, whereas in the other group respective values were 50 (16) years and 56%. All patients were receiving treatment for cancer. Resolution of thrombus had occurred in 53.5% at 1 month, 76.1% at 2 months, and 92.6% at 3 months in the rivaroxaban-treated patients. Corresponding values in the LMW heparin/vitamin antagonist-treated patients were 34.2%, 55.5%, and 88.5%, respectively. Differences between groups were significant at 1 month (P < 0.01) and 2 months (P < 0.05). There were no major bleeds in either group, and cumulative bleeding rates by 3 months were 7.3% in the rivaroxaban group and 11.4% in the LMW heparin/vitamin K antagonist group.

IMPLICATIONS

Rivaroxaban led to faster resolution of PICC-associated UEDVT than LMW/vitamin K antagonists without any increase in bleeding.

Current practice patterns and patient persistence with anticoagulant treatments for cancer-associated thrombosis

BACKGROUND

Recommended therapeutic options for the management of venous thromboembolism (VTE) in patients with cancer are burdensome, and compliance with guidelines is unknown.

OBJECTIVES

To describe current treatment patterns and to evaluate patient persistence on various anticoagulants.

PATIENTS/METHODS

Medical and pharmacy claims from the Humana Database were analyzed (01/2007-12/2014). Newly diagnosed cancer patients treated with anticoagulants were categorized into one of the following cohorts: low-molecular-weight heparin (LMWH), warfarin, and rivaroxaban. Discontinuation, switching, and persistence with the index therapy were analyzed.

RESULTS

A total of 2941 newly diagnosed patients with cancer who developed VTE and received anticoagulation in outpatient settings were identified. Of these, 97% initiated anticoagulation with LMWH (n=735; 25%), warfarin (n=1403; 47.7%), or rivaroxaban (n=709; 24.1%). Median treatment durations for the LMWH, warfarin, and rivaroxaban cohorts were 3.3, 7.9, and 7.9 months, respectively; Kaplan-Meier rates of persistence to the initial therapy were 37%, 61%, and 61% at 6 months. Warfarin and rivaroxaban users were significantly more likely to remain on initial therapy compared to LMWH (adjusted hazard ratios [HRs; 95% CI]: warfarin, 0.33 [0.28-0.38]; rivaroxaban, 0.38 [0.32-0.46]). The proportion of patients that switched from their initial treatment to another anticoagulation treatment was 22.9%, 7.9%, and 4.7% in the LMWH, warfarin, and rivaroxaban cohorts, respectively.

CONCLUSIONS

This real-world analysis showed that, despite guideline recommendations, warfarin and rivaroxaban are at least as equally utilized as LMWH for the treatment of cancer-associated thrombosis. LMWH was associated with significantly lower persistence, shorter duration of treatment, and more switching than warfarin and rivaroxaban.

Long-term treatment of cancer-associated thrombosis: the choice of the optimal anticoagulant

Patients with cancer-associated thrombosis (CAT) carry a higher risk of recurrence, bleeding and mortality as compared with non-cancer patients. The specific profiles of cancer patients, combining frequent co-morbidities, the use of anti-tumoral therapies and the cancer progression itself, represent a major therapeutic challenge for choosing a long-term anticoagulant treatment. This review discusses the practical basis of making a choice between the available drugs for a long-term antithrombotic strategy, linked to their pharmacology, mechanism of action, evidence of clinical benefits, and advantages and limitations in such a complex clinical context. In patients with cancer, low-molecular-weight heparins (LMWHs) are the preferred option for the secondary prevention of venous thromboembolism according to current guidelines, because their efficacy is significantly superior to vitamin K antagonists (VKAs). Even though LMWHs are effective and safe in cancer patients, they require daily subcutaneous injections, which may be problematic for a long-term therapy that may exceed 6 months' duration. Compared with VKAs, non-vitamin-K antagonist oral anticoagulants or direct oral anticoagulants (DOACs) are more target specific and do not require laboratory monitoring, whereas the oral route of administration makes them potentially attractive alternatives to LMWH. In randomized controlled trials in the general population DOACs have been shown to be non-inferior to VKAs in terms of efficacy with a lower rate of clinically relevant or major bleeding. However, given the limited number of cancer patients enrolled in these studies (with poorly defined active cancer), available trials are inconclusive regarding the usefulness of DOACs in the cancer setting. Ongoing head-to-head comparisons vs. LMWH in patients with CAT may allow an informed choice to be made regarding the DOAC option.

The treatment of cancer associated thrombosis: does one size fit all? Who should get LMWH/warfarin/DOACs?

Whilst the term cancer associated thrombosis (CAT) offers an overarching term for all thrombotic events encountered during the cancer journey, the reality is that this is a far too simplistic reflection of a complex multifactorial process occurring within a heterogeneous population. The management of CAT needs to consider factors beyond the thrombus itself: patients must be treated as individuals within the context of their own cancer journey and their preferences for different treatment options. The breath of pathological, pharmacological and psychosocial variants means it is highly unlikely that one treatment regime will be appropriate for all patients. It is inevitable that regimes may need to be modified and anticoagulant agents changed according to clinical and patient preference needs. There is strong evidence supporting the use of low molecular weight heparin first line in the treatment of acute CAT. The evidence for warfarin and the direct acting oral anticoagulants is not as strong but, as oral agents, may be preferred by some patients. This paper shall identify the various treatment options available, factors which will influence the decision making process and when it is justifiable to treat patients differently to the established protocol.

Factors Affecting the Quality of Anticoagulation With Vitamin K Antagonists in Venous Thromboembolism Patients

Introduction:

Treatment of venous thromboembolism (VTE) is classically based on oral vitamin K antagonists (VKAs). Due to the disadvantages and side effects of these drugs, monitoring the quality of anticoagulation by assessing time within therapeutic range (TTR) is recommended. Variables altering the TTR in patients with VTE are yet to be determined. The aim of this study was to analyze the quality of anticoagulation in patients with VTE treated with VKAs and to identify factors associated with poor-quality anticoagulation.

Methods:

A retrospective observational study was performed in a cohort of 94 patients diagnosed with VTE undergoing treatment with VKAs. The TTR at 6 months was analyzed by the Rosendaal method. Univariate and a multivariate logistic regression analyses were performed to unravel factors that increase risk of poor-quality anticoagulation.

Results:

The TTR at 6 months in this cohort was 60.5%; 54 patients had a TTR < 65%. In the univariate analysis, female sex, age ≥ 65 years, and renal impairment were significantly associated with poor-quality anticoagulation. However, in the multivariate logistic regression model, only renal impairment was independently associated with poor-quality anticoagulation (odds ratio = 3.31, 95% confidence interval [1.049, 10.486], p = .041).

Discussion:

The average quality of anticoagulation was 60.5%, and a high percentage of patients had a quality of anticoagulation below recommended levels. Study findings indicate that renal impairment is an independent risk factor for poor-quality anticoagulation in patients with VTE treated with VKAs.

Assessing patients' anticoagulation preferences for the treatment of cancer-associated thrombosis using conjoint methodology

Low molecular weight heparins have demonstrated superiority over coumarins in the extended treatment of cancer-associated thrombosis and are recommended as first-line therapy in clinical guidelines. Non-vitamin K oral antagonists are yet to be evaluated against low molecular weight heparin for this indication. Nevertheless, a perception that patients favor oral anticoagulants over injections may lead to an increased prescribing of warfarin or non-vitamin K oral antagonists despite the evidence gap. There has been no evaluation of cancer patient preferences for anticoagulants and whether such an evidence gap is an acceptable trade-off for patients prescribed orals. We conducted a study to assess what features are most important to CAT patients regarding their choice of anticoagulant. Two modules were applied: Initial in-depth interviews with 9 patients diagnosed with cancer-associated thrombosis, and thereafter quantitative research, where a further 100 patients completed a choice-based-conjoint exercise, where 15 different scenarios were presented to identify the most important attributes of an anticoagulant. Seventy percent of the patients were treated with injected medication (low molecular weight heparin) and 30% with oral medications. Patients most valued an anticoagulant with minimal interference with their cancer treatment (39%), low thrombosis recurrence rate (24%), and low risk of major bleed (19%). Preference for oral administration over injection had moderate importance (13%). The results show that patients prefer an anticoagulant that does not interfere with their cancer treatment, suggesting the primacy of the cancer disease over venous thromboembolism in these patients. Patients also favor efficacy and safety over convenience of route of administration.

Heparins – DOACS – VKA

Patients with cancer are at increased risk of venous thromboembolism (VTE). At the same time they have often an underlying bleeding risk. That can often make decisions surrounding the administration of anticoagulants complicate. Individual risk-benefit calculation is necessary. During hospital stage the patients get, if there are no contraindications, a medical VTE prophylaxis with low molecular weight heparin (LMWH). Whereas out-patients don’t get a prophylaxis because they are at low risk of thromboembolism. If additional risk factor for VTE exists a decision for medical VTE prophylaxis should be taken into account. In patients with cancer and acute VTE, LMWH is recommended as treatment of choice for initial and long-term management in a body weight adapted dosage. After a period of 3–6 month and if a prolonged treatment is necessary, guidelines allow to switch from LMWH to VKA for further anticoagulant therapy. Beside the established anticoagulants like heparin, vitamin K antagonists, fondaparinux new oral direct anticoagulants (DOACs) were established in the last years. These substances are evaluated in in clinical trials. They are approved for treatment of acute VTE, for secondary prophylaxis and for prevention of ischemic stroke in patients with arterial fibrillation. In the VTE trials, 4–10 % of the enrolled patients had a history of cancer. The data shows that DOACs can prevent recurrent VTE as good as standard therapy with enoxaparin/warfarin without more bleeding complications. The results are encouraging. Because of the limited data the direct oral anticoagulants are not recommended for treatment of VTE at this time. Further studies are necessary.

Cancer cells BXPC3 and MCF7 differentially reverse the inhibition of thrombin generation by apixaban, fondaparinux and enoxaparin

INTRODUCTION

Cancer cells may alter the efficiency of the antithrombotic agents. To explore this possibility, the present study compared the capacity of the LMWH enoxaparin and the specific inhibitors of Xa (apixaban and fondaparinux) to inhibit thrombin generation triggered by pancreas adenocarcinoma cells (BXPC3) and human breast carcinoma cells (MCF7).

MATERIALS AND METHODS

Samples of platelet poor (PPP) or platelet rich plasma (PRP) spiked with apixaban, fondaparinux or enoxaparin were added in micro wells carrying cancer cells and assessed for thrombin generation. In the control experiment thrombin generation was triggered with tissue factor reagent.

RESULTS

The three antithrombotics inhibited thrombin generation in a concentration dependent manner. The BXPC3 and MCF7 cells reversed in a different intensity the effect of the studied agents. According to the histological type of the cancer the antithrombotic efficiency of apixaban was preserved or partially reversed. Fondaparinux, was more vulnerable to the presence of cancer cells as compared to apixaban. The effect of BXCP3 or MCF7 cells on the antithrombotic potency of enoxaparin was of similar magnitude as that on apixaban.

CONCLUSIONS

The type of cancer cells is determinant for the antithrombotic efficiency of the specific factor Xa inhibitors. In contrast it does not significantly influence the potency of enoxaparin. The present study shows that the impact of the type of cancer cells on the antithrombotic activity of the specific Xa inhibitors should not be neglected. This has to be taken into consideration for the design of dose-finding studies of the direct orally active FXa inhibitors in patients with different histological types of cancer.