New oral anticoagulants and the cancer patient

Antithrombotic Therapy in Cancer Patients with Cardiovascular Diseases: Daily Practice Recommendations by the Hemostasis Working Party of the German Society of Hematology and Medical Oncology (DGHO) and the Society for Thrombosis and Hemostasis Research (GTH e.V.)

Active cancer by itself but also chemotherapy is associated with an increased risk of cardiovascular disease (CVD) and especially coronary artery disease (CAD) and atrial fibrillation (AF). The frequency of CVD, CAD, and AF varies depending on comorbidities (particularly in older patients), cancer type, and stage, as well as the anticancer therapeutic being taken. Many reports exist for anticancer drugs being associated with CVD, CAD, and AF, but robust data are often lacking. Because of this, each patient needs an individual structured approach concerning thromboembolic and bleeding risk, drug-drug interactions, as well as patient preferences to evaluate the need for anticoagulation therapy and targeting optimal symptom control. Interruption of specific cancer therapy should be avoided to reduce the potential risk of cancer progression. Nevertheless, additional factors like thrombocytopenia and anticoagulation in the elderly and frail patient with cancer cause additional challenges which need to be addressed in daily clinical management. Therefore, the aim of these recommendations is to summarize the available scientific data on antithrombotic therapy (both antiplatelet and anticoagulant therapy) in cancer patients with CVD and in cases of missing data providing guidance for optimal careful decision-making in daily routine.

Mechanisms, prevalence and management of cardiac arrhythmias in cancer patients: a comprehensive review

Recently, prognosis and survival of cancer patients has improved due to progression and refinement of cancer therapies; however, cardiovascular sequelae in this population augmented and now represent the second cause of death in oncological patients. Initially, the main issue was represented by heart failure and coronary artery disease, but a growing body of evidence has now shed light on the increased arrhythmic risk of this population, atrial fibrillation being the most frequently encountered. Awareness of arrhythmic complications of cancer and its treatments may help oncologists and cardiologists to develop targeted approaches for the management of arrhythmias in this population. In this review, we provide an updated overview of the mechanisms triggering cardiac arrhythmias in cancer patients, their prevalence and management.

The Role of Injectables in the Treatment and Prevention of Cancer-Associated Thrombosis

Cancer-associated thrombosis (CAT) is a leading cause of death among patients with cancer. CAT can manifest itself as venous thromboembolism (VTE), in the form of deep vein thrombosis or pulmonary embolism, or arterial thromboembolism. The pathophysiology of CAT is complex and depends on cancer-, patient-, treatment- and biomarkers-related factors. Treatment of VTE in patients with cancer is complex and includes three major classes of anticoagulant agents: heparin and its derivatives, e.g., low molecular weight heparins, direct oral anticoagulants (DOACs), and vitamin K inhibitors. Given the tremendous heterogeneity of clinical situations in patients with cancer and the challenges of CAT, there is no single universal treatment option for patients suffering from or at risk of CAT. Initial studies suggested that patients seemed to prefer an anticoagulant that would not interfere with their cancer treatment, suggesting the primacy of cancer over VTE, and favoring efficacy and safety over convenience of route of administration. Recent studies show that when the efficacy and safety aspects are similar, patients prefer the oral route of administration. Despite this, injectables are a valid option for many patients with cancer.

Construction and validation of a nomogram of risk factors for new-onset atrial fibrillation in advanced lung cancer patients after non-surgical therapy

Objective

Risk factors of new-onset atrial fibrillation (NOAF) in advanced lung cancer patients are not well defined. We aim to construct and validate a nomogram model between NOAF and advanced lung cancer.

Methods

We retrospectively enrolled 19484 patients with Stage III-IV lung cancer undergoing first-line antitumor therapy in Shanghai Chest Hospital between January 2016 and December 2020 (15837 in training set, and 3647 in testing set). Patients with pre-existing AF, valvular heart disease, cardiomyopathy were excluded. Logistic regression analysis and propensity score matching (PSM) were performed to identify predictors of NOAF, and nomogram model was constructed and validated.

Results

A total of 1089 patients were included in this study (807 in the training set, and 282 in the testing set). Multivariate logistic regression analysis showed that age, c-reactive protein, centric pulmonary carcinoma, and pericardial effusion were independent risk factors, the last two of which were important independent risk factors as confirmed by PSM analysis. Nomogram included independent risk factors of age, c-reactive protein, centric pulmonary carcinoma, and pericardial effusion. The AUC was 0.716 (95% CI 0.661-0.770) and further evaluation of this model showed that the C-index was 0.716, while the bias-corrected C-index after internal validation was 0.748 in the training set. The calibration curves presented good concordance between the predicted and actual outcomes.

Conclusion

Centric pulmonary carcinoma and pericardial effusion were important independent risk factors for NOAF besides common ones in advanced lung cancer patients. Furthermore, the new nomogram model contributed to the prediction of NOAF.

Treatment of Cancer-Associated Thrombosis: Recent Advances, Unmet Needs, and Future Direction

Cancer-associated thrombosis, with the incidence rising over the years, is associated with significant morbidity and mortality in patients with cancer. Recent advances in the treatment of cancer-associated venous thromboembolism (VTE) include the introduction of direct oral anticoagulants (DOACs), which provide a more convenient and effective option than low-molecular-weight heparin (LMWH). Nonetheless, important unmet needs remain including an increased risk of bleeding in certain patient subgroups such as those with gastroesophageal cancer, concerns about drug-drug interactions, and management of patients with severe renal impairment. Although DOACs are more convenient than LMWH, persistence can decline over time. Factor XI inhibitors have potential safety advantages over DOACs because factor XI appears to be essential for thrombosis but not hemostasis. In phase II trials, some factor XI inhibitors were superior to enoxaparin for the prevention of VTE after knee replacement surgery without increasing the risk of bleeding. Ongoing trials are assessing the efficacy and safety of factor XI inhibitors for the treatment of cancer-associated VTE.

Clinical trial assessing the safety of edoxaban with concomitant chemotherapy in patients with gynecological cancer-associated thrombosis (EGCAT study)

BACKGROUND

Gynecological cancer is one of the highest risk factors for cancer-associated thrombosis (CAT). Although low-molecular-weight heparin (LMWH) is recommended as an anticoagulant for treating CAT, recent studies have shown that direct oral anticoagulants (DOACs) are an acceptable alternative. Patients with cancer require a series of chemotherapies concomitantly with DOAC administration; however, the extent to which these drugs influence DOAC blood concentrations is unknown. In this study, we measured the plasma concentration of edoxaban during chemotherapy for gynecological cancers to determine its safety.

METHODS

Patients histologically diagnosed with ovarian or uterine corpus cancer and CAT were recruited after primary surgery and before the initiation of postoperative adjuvant chemotherapy, including paclitaxel. Patients were administered edoxaban (30 or 60 mg) orally for CAT. The plasma concentrations of edoxaban and active factor Xa were determined and their percentage change before and after chemotherapy was calculated. Additionally, blood coagulation tests were analyzed.

RESULTS

Sixteen patients with gynecological cancer (12 with ovarian cancer and 4 with uterine corpus cancer) were enrolled. Among these, 15 samples were collected one day after chemotherapy initiation. During chemotherapy, the trough concentration of edoxaban changed from 17.6 ± 10.6 to 20.0 ± 15.6 ng/ml, and the mean percentage change in edoxaban concentration was 14.5%. Therefore, the trough concentrations of edoxaban, which represent excretion capacity, were not significantly increased by chemotherapy with paclitaxel. The area under the plasma edoxaban concentration-time curve and the active factor Xa concentration were also unaffected.

CONCLUSION

Patients with CAT and ovarian or uterine corpus cancer administered edoxaban orally showed no significant increase in the trough concentration of edoxaban while undergoing chemotherapy. This suggests the safety of edoxaban use during the treatment of gynecological cancers.

TRIAL REGISTRATION

EGCAT study; Japan Registry of Clinical Trials, jRCTs051190024.

Direct-Acting Oral Anticoagulant Therapy in Cancer Patients-A Review

Venous thromboembolism (VTE) is an important aspect in cancer patients. There are various pharmacological methods used for thrombotic event treatment. DOACs (direct-acting oral anticoagulants) are gaining popularity among both physicians and researchers and are slowly starting to replace VKAs (vitamin K antagonists), thus becoming a substitute or alternative option for LMWHs (low-molecular-weight heparins). In this article, we present DOACs' main therapeutic advantages and disadvantages in patients with cancer. The only major concern with using DOACs is the higher risk of bleeding; however, there are discrepancies in this matter. There are still some types of cancer for which DOACs are not recommended. Specific cancer types may influence the efficacy of DOAC therapy. Additionally, race and ethnicity may affect therapy in cancer patients with DOACs. A sizeable number of clinical trials are focused on comparing DOACs with other anticoagulants. The current guidelines of different scientific associations are not unanimous in their DOAC assessments. There is still a need for more evidence of DOACs' potential advantages over other methods of anticoagulation in cancer patients to facilitate their position in this recommendation. This literature review presents the current state of knowledge about the use of DOACs in patients with neoplastic growth.

Cancer-Associated Thrombosis: A Taiwanese Perspective on Therapeutic Options with Focus on Non-Vitamin K Antagonist Oral Anticoagulants

Cancer-associated thrombosis (CAT) is a common complication of malignancies. Patients with CAT are at risk of venous thromboembolism recurrence, but also at risk of bleeding while anticoagulated. Taiwanese patients are perceived to have a lower incidence of CAT, likely leading to false reassurance for Taiwanese patients with cancer. Because of this, oncologists and cardiologists from multiple medical institutions in Taiwan have set forth to provide clinical consensus guidelines on the management of CAT, based on local clinical practices and guided by predominant international clinical practice guidelines. This paper aims to describe the current disease burden of cancer-associated venous thromboembolism in Taiwanese cancer patients, and discusses the unmet needs and gaps in the management of this medical complication. It also outlines diagnostic and management strategies relevant to the different treatment options available, such as non-vitamin K antagonist oral anticoagulants.

[Prophylaxis and management of cancer-associated thrombosis: Practical issues about anticoagulant use]

Cancer-associated thrombosis (CAT) is a common complication resulting from various vascular mechanisms related to cancer, antitumoral therapy and patient status, and is associated with a poor prognosis. Anticoagulants recommended for CAT treatment or prevention mainly include low molecular weight heparin (LMWH) and direct oral anticoagulants (DOACs). Regarding thromboprophylaxis, a situation for which LMWH is a preferred option due to a lower risk of hemorrhage especially in patients with unresected gastro-intestinal and genito-urinary malignancies, the identification of patients at risk is a major issue. For patients with established CAT, the main issue is the choice of the most appropriate anticoagulant therapy. Because of the convenience of oral formulation, DOACs are an attractive option, and their efficacy has been shown in randomized trials. However, such studies are limited by selection biases, which make the analyzed population not representative of the real-life setting, as for instance cancers associated with a high risk of hemorrhage, or antitumoral therapies (e.g., tyrosine kinase inhibitors) known to interact with DOACs and then modifying their bioavailability. Caution associated with DOAC use is highlighted by most updated guidelines that recommend a case-by-case-based approach. The aim of the present paper is to help the oncologists make the most appropriate decision regarding the choice of anticoagulant therapy in a context of thromboprophylaxis or established CAT management in a patient with a solid tumor. The main issues are addressed through key practical questions, the answers of which are based on the current guidelines and additional published data or expert opinions.

Net clinical benefit of DOACs vs. usual anticoagulation treatment in venous thromboembolism and active cancer: systematic review and meta-analysis

Patients with active cancer are at high risk of recurrent venous thromboembolism (VTE). Usual treatment includes low molecular weight heparin (LMWH), while vitamin K antagonists (VKAs) have also been used as substitutes for LMWH. Direct oral anticoagulants (DOACs) are considered a beneficial alternative to the usual treatment but are accompanied by an increased rate of bleeding compared to LMWH. We conducted a meta-analysis to evaluate the benefits and harms under a common denomination, namely the net clinical benefit (NCB), between DOACs and usual anticoagulation. The primary outcome was NCB-1, defined as non-fatal VTE, major non-fatal bleedings, and all-cause mortality). Co-primary outcomes were 1) NCB-2 (i.e., NCB-1 and clinically relevant non-major bleedings) and 2) NCB-3 (i.e., fatal or non-fatal VTE and major bleedings). A random-effects model was used to calculate outcome risk ratios and 95% confidence intervals (CI). Prospective Register of Systematic Reviews identification number CRD42021284238. We selected 8 studies (n = 4,4461 patients; mean follow-up, 6 months). The NCB-1 and -2 were not different between DOACs and usual anticoagulation, while the NCB-3 showed a reduction of 28% (95% CI, 10-42%), favoring DOACs. Recurrent VTE was reduced by 40% (95% CI, 25-53%) with DOACs than the usual treatment. Different bleeding outcomes and all-cause mortality were not different between treatments. All primary outcomes did not differ between DOACs and LMWH, while NCB-2 and NCB-3 were reduced with DOACs than VKAs. The NCB of DOACs was similar or more favorable to usual anticoagulation in patients with active cancer due to a substantial reduction of VTE and no bleeding excess.

The 5 most frequently asked questions about factor Xa inhibitors

Direct oral anticoagulants (DOACs) are commonly used oral factor Xa inhibitors in recent years. However, in some special clinical situations, the appropriate use of these anticoagulants may be of concern. In this article, we address the 5 commonly asked questions regarding their use for the treatment of venous thromboembolism, including in the setting of obesity, renal impairment, gastrointestinal (GI) malignancy, catheter-related thrombosis, and drug-drug interactions. Data on the use of DOACs in the presence of significant obesity or renal failure are mainly observational. Some DOACs are shown to have an increased risk of bleeding in patients with unresected luminal GI malignancy but not others, so selection of appropriate patients is the key. Furthermore, literature on the use of DOACs for catheter-related thrombosis or when drug-drug interactions are of concern is limited, and more research is welcome.

Venous Thromboembolism in Women with Cancer with an Additional Focus on Breast and Gynecological Cancers

Cancer-associated venous thromboembolism (VTE) is common in women with cancer. Many clinical practice guidelines provide guidance for prevention and treatment; however, there are no specific recommendations for women. This is unfortunate because the proportion of women with breast- and gynecological cancers is high among patients with cancer-associated VTE. Thromboembolism often heralds cancer progression and poor prognosis and should—besides adequate anticoagulant management—also prompt reassessment and, if necessary, changes in cancer treatment. Recently, the new class of direct-acting oral anticoagulants (DOACs) has started to replace low-molecular-weight heparin as standard thromboprophylaxis and therapy in cancer patients. They are very effective, but they also carry a relevant risk of bleeding. Therefore, despite their ease of use, not every tumor patient qualifies for a DOAC, and this is especially true for gynecological tumor patients. Each prescription must be weighed individually. This review addresses specific aspects of VTE prophylaxis and management in women with cancer. Every physician who treats breast and gynecological cancers should be familiar with prophylaxis, diagnosis, and therapy of cancer-associated VTE. At the same time, patients should be informed by their physician what symptoms to look for and whom to contact if these symptoms occur, even outside of office hours and on weekends.

Incidence of stroke in the first year after diagnosis of cancer-A systematic review and meta-analysis

Background

Patients newly diagnosed with cancer represent a population at highest risk for stroke. The objective of this systematic review and meta-analysis was to estimate the incidence of stroke in the first year following a new diagnosis of cancer.

Methods

We searched MEDLINE and EMBASE from January 1980 to June 2021 for observational studies that enrolled adults with a new diagnosis of all cancers excluding non-melanoma skin cancer, and that reported the incidence of stroke at 1 year. PRISMA guidelines for meta-analyses were followed. Two reviewers independently extracted data and appraised risk of bias. We used the Dersimonian and Laird random effects method to pool cumulative incidences after logit transformation, and reported pooled proportions as percentages. Statistical heterogeneity was assessed using the I 2 statistic.

Results

A total of 12,083 studies were screened; 41 studies were included for analysis. Data from 2,552,121 subjects with cancer were analyzed. The cumulative incidence of total stroke at 1 year was 1.4% (95% CI 0.9-2.2%), while the pooled incidence of ischemic stroke was 1.3% (95% CI 1.0-1.8%) and 0.3% (95% CI 0.1-0.9%) for spontaneous intracerebral hemorrhage (ICH), with consistently high statistical heterogeneity (>99% I 2).

Conclusion

The estimated incidence of stroke during the first year after a new diagnosis of cancer is 1.4%, with a higher risk for ischemic stroke than ICH. Cancer patients should be educated on the risk of stroke at the time of diagnosis. Future studies should evaluate optimal primary prevention strategies in this high-risk group of patients.

Systematic review registration

https://osf.io/ucwy9/.

Practical Considerations for the Management of Cancer-Associated Venous Thromboembolism: A Guide for the General Oncology Practitioner

Cancer-associated venous thromboembolism is a devastating complication of cancer and is associated with significant morbidity and mortality. The cornerstone of cancer-associated venous thromboembolism treatment is anticoagulation, and in recent years, there have been notable randomized clinical trials that have revealed insights into the efficacy and safety of direct oral anticoagulants and low-molecular-weight heparin in the treatment of cancer-associated thrombosis. Deciding on the ideal anticoagulation treatment plan for a patient with a cancer-associated thrombosis is a complex task that requires an understanding of clinical trial data, society guidelines, and, most importantly, consideration of many cancer-related, treatment-related, and patient-related factors. This article summarizes important factors to consider when deciding on anticoagulation therapy for a patient with cancer-associated thrombosis.

Atypical kinetics of cytochrome P450 enzymes in pharmacology and toxicology

Atypical kinetics are observed in metabolic reactions catalyzed by cytochrome P450 enzymes (P450). Yet, this phenomenon is regarded as experimental artifacts in some instances despite increasing evidence challenging the assumptions of typical Michaelis-Menten kinetics. As P450 play a major role in the metabolism of a wide range of substrates including drugs and endogenous compounds, it becomes critical to consider the impact of atypical kinetics on the accuracy of estimated kinetic and inhibitory parameters which could affect extrapolation of pharmacological and toxicological implications. The first half of this book chapter will focus on atypical non-Michaelis-Menten kinetics (e.g. substrate inhibition, biphasic and sigmoidal kinetics) as well as proposed underlying mechanisms supported by recent insights in mechanistic enzymology. In particular, substrate inhibition kinetics in P450 as well as concurrent drug inhibition of P450 in the presence of substrate inhibition will be further discussed. Moreover, mounting evidence has revealed that despite the high degree of sequence homology between CYP3A isoforms (i.e. CYP3A4 and CYP3A5), they have the propensities to exhibit vastly different susceptibilities and potencies of mechanism-based inactivation (MBI) with a common drug inhibitor. These experimental observations pertaining to the presence of these atypical isoform- and probe substrate-specific complexities in CYP3A isoforms by several clinically-relevant drugs will therefore be expounded and elaborated upon in the second half of this book chapter.

Complexity and clinical significance of drug-drug interactions (DDIs) in oncology: challenging issues in the care of patients regarding cancer-associated thrombosis (CAT)

Cancer patients have an increased risk of developing venous thromboembolic events. Anticoagulation management includes prophylactic or therapeutic doses of low molecular weight heparins (LMWHs) or direct oral anticoagulants (DOACs). However, the management of thrombosis in patients with cancer is complex due to various individual and disease-related factors, including drug–drug interactions (DDIs). Furthermore, DDIs may impact both, cancer and venous thrombosis, treatment effectiveness and safety; their relevance is highlighted by the advances in cancer therapeutics. Given that these new oncology drugs are extensively used, more attention should be given to monitoring potential DDIs to minimize risks. Recognition of DDIs is of utmost importance in an era of rapid developments in cancer treatments and introduction of novel treatments and protocols. When managing cancer-associated thrombosis (CAT), the concomitant use of a DOAC and a moderate or strong modulator (inhibitor or inducer) of CYP3A4 or a P-glycoprotein (P-gp) is most likely to be associated with significant DDIs. Therefore, LMWHs remain the first-line option for the long-term management of CAT under these circumstances and physicians must consider utilizing LMWHs as first line. This review describes the risk of DDIs and their potential impact and outcomes in patients with cancer associated thrombosis (CAT) receiving anticoagulation.

Hemorrhage Risk Among Patients With Breast Cancer Receiving Concurrent Direct Oral Anticoagulants With Tamoxifen vs Aromatase Inhibitors

Importance

Tamoxifen is commonly used as adjuvant therapy in breast cancer and is proposed to interfere with cytochrome P450 enzyme and P-glycoprotein pathways. Concurrent use with direct oral anticoagulants (DOACs) poses the threat of a potentially dangerous drug-drug interaction by leading to an increase in hemorrhage risk.

Objective

To assess the risk of hemorrhage in patients with breast cancer coprescribed a DOAC and tamoxifen compared with a DOAC and an aromatase inhibitor (AI).

Design, Setting, and Participants

This population-based, retrospective cohort study was conducted among adults aged 66 years or older who were prescribed tamoxifen (compared with an AI) concurrently with a DOAC in Ontario, Canada, between June 23, 2009, and November 30, 2020, and followed up until December 31, 2020.

Interventions

Concurrent prescription of a DOAC and tamoxifen compared with a DOAC and an AI.

Main Outcomes and Measures

The primary outcome was major hemorrhage requiring an emergency department visit or hospitalization after prescription. Overlap weighted Cox proportional hazards models, accounting for multiple covariates, were used to assess the association between hemorrhage and tamoxifen or AI use with a DOAC.

Results

Among a total of 4753 patients (4679 [98.4%] women; mean [SD] age, 77.4 [7.4] years), 1179 (24.8%) were prescribed tamoxifen, and 3574 (75.2%) were prescribed an AI. Rivaroxaban (2530 [53.2%]) and apixaban (1665 [35.0%]) were the most frequently used DOACs. Patients taking AIs were younger than patients taking tamoxifen (mean [SD] age, 77.1 [7.3] vs 78.3 [7.6] years), with higher Charlson Comorbidity Index (mean [SD], 1.8 [2.4] vs 1.5 [2.2]) and more advanced cancer stage (stages III and IV, 569 [15.9%] vs 127 [10.8%]). During a median follow-up of 166 days (IQR, 111-527 days), tamoxifen was not associated with a higher risk of major hemorrhage (29 of 1179 [2.5%]) compared with an AI (119 of 3574 [3.3%]) when combined with a DOAC (absolute risk difference, -0.8%; weighted hazard ratio, 0.68 [95% CI, 0.44-1.06]). These results were similar in additional analyses using a more liberal definition of hemorrhage, accounting for kidney function, limiting follow-up to 90 days, stratifying by incident and prevalent DOAC users, and accounting for cancer duration and the competing risk of death.

Conclusions and Relevance

In this cohort study, findings suggest that among DOAC users, the concurrent use of tamoxifen was not associated with a higher risk of hemorrhage compared with the concurrent use of an AI. These findings should directly inform prescribers regarding the apparent safety of concurrent DOAC and tamoxifen use.

Can thromboprophylaxis build a link for cancer patients undergoing surgical and/or chemotherapy treatment? The MeTHOS cohort study

BACKGROUND

Patients with active cancer have a 4-sevenfold increased risk for venous thromboembolism (VTE) especially during systematic anticancer treatment. Simultaneously, surgery is an additional risk factor.

METHODS

The Metaxas's Hospital THromboprophylaxis program in Oncological & Surgical Patients (MeTHOS) is a prospective, phase IV, observational, non-interventional cohort study, aiming to record the thromboprophylaxis practice patterns in high-risk active cancer patients undergoing surgical and/or chemotherapy treatment.

RESULTS

We are reporting results from 291 ambulatory patients (median age: 67 years, Q1-Q3: 59-73 years, 54.6% males) who received anti-neoplastic treatment and administered thromboprophylaxis. 59.8% had cardiovascular disease (mostly hypertension), 76.6% were reported as having at least one comorbidity, while 27.5% and 15.8% accumulated two and three comorbidities, respectively. 94.9% of the patients were receiving highly thrombogenic agents such as platinum-based agents, 5-FU, immunotherapy, antiangiogenics/anti-VEGF, or erythropoietin. 26.5% of the patients were initially surgically treated. In terms of anticoagulation, all patients were treated with tinzaparin (fixed dose, 10,000 Anti-Xa IU, OD). The median anticoagulation duration was 6.2 months. Six thrombotic events were observed (2.06%, 95% CI: 0.76-4.43%): 5 were DVT, and one PE. With respect to safety, 7 bleeding events occurred (2.6%, 95% CI: 1.0-5.3%); 6 of them were minor.

CONCLUSIONS

Thromboprophylaxis with LMWH in patients with active cancer and high thrombotic burden was safe and effective. Intermediate dose of tinzaparin seems to be an appropriate agent for cancer-associated thromboprophylaxis management.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT04248348.

Apis mellifera syriaca Venom: Evaluation of Its Anticoagulant Effect, Proteolytic Activity, and Cytotoxicity along with Its Two Main Compounds-MEL and PLA2-On HeLa Cancer Cells

Bee venom (BV) is one of the most remarkable natural products that has been a subject of studies since ancient times. Recent studies have shown that Apis mellifera syriaca venom possesses antibacterial as well as cytotoxic effects on cancer cell lines. The venom contains a variety of bioactive molecules-mainly melittin (MEL) and phospholipase A2 (PLA2), as well as other compounds that are not well characterized. In this work, we continue the biological characterization of A. mellifera syriaca venom by testing its anticoagulant effect on human plasma using the prothrombin time (PT) test, as well as assessing its proteolytic activity. In addition, the cytotoxicity of the crude venom-and of its two main components, MEL and PLA2-was tested on HeLa cancer cell lines for the first time. The results obtained showed the capacity of A. mellifera syriaca venom to increase clotting time, thereby proving its anticoagulant effect. Moreover, the venom did not demonstrate a significant proteolytic activity unless administrated at concentrations ≥ 5 mg/mL. Finally, we showed that crude A. mellifera syriaca venom, along with MEL, exhibit a strong in vitro cytotoxic effect on HeLa cancer cell lines, even at low concentrations. In summary, our findings could serve as a basis for the development of new natural-based drug candidates in the therapeutic field.

Prophylaxis of cancer‑associated venous thromboembolism with low‑molecular‑weight heparin‑tinzaparin: Real world evidence

Thromboprophylaxis, as a preventive measure for cancer-associated thrombosis (CAT), may be beneficial for patients with active cancer and high-risk for thrombosis. The present post hoc analysis include a total of 407 patients enrolled in the Greek Management of Thrombosis study, who received thromboprophylaxis with tinzaparin. The objectives of the present analysis were: i) To obtain sufficient evidence for the administration of prophylaxis in patients with active cancer, irrespective of Khorana risk assessment model score; ii) to identify the selection criteria for both dose and duration of tinzaparin; and iii) to evaluate the efficacy and safety of tinzaparin administered for CAT prophylaxis. The main tumor types for the patients included in the present study were as follows: Lung (25.1%), pancreatic (14.3%), breast (9.1%), stomach (8.4%), colorectal (7.9%) and ovarian (7.6%). Furthermore, metastatic disease was observed in 69.5% of the patients. High thrombotic burden agents (HTBAs) were administered to 66.3% of the patients, and 17.4% received erythropoietin. A total of 43.7% of the patients exhibited a Khorana score <2. The results of the present study demonstrated that both the presence of metastatic disease and the use of HTBAs seemed to influence oncologists' decisions for the use of thromboprophylaxis in patients with active cancer, regardless of Khorana score. Tinzaparin, in dose expressed in the standard notation for heparins, i.e., anti-Xa factor international units (Anti-Xa IU), was administered at an intermediate dose (InterD; 8,000-12,000 Anti-Xa IU; once daily) to 52.4% of patients, while the remaining patients received a prophylactic dose (ProD; ≤4,500 Anti-Xa IU; once daily). The average duration of thromoprophylaxis was 5 months. Furthermore, a total of 14 (3.4%) thrombotic events and 6 (1.5%) minor bleeding events were recorded. A total of four thrombotic events were observed following an InterD treatment of tinzaparin, while 10 thrombotic events were observed following ProD treatment. The present study also demonstrated that an InterD of tinzaparin was administered more frequently to patients with a body mass index >30 kg/m², a history of smoking and a history of metastatic disease, along with administration of erythropoietin. InterD tinzaparin treatment was found to be potentially more efficacious and without safety concerns. The present study is a registered clinical trial (ClinicalTrials.gov code, NCT03292107; registration date, September 25, 2017).

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.

Esophagectomy combined with off-pump coronary artery bypass grafting through left posterolateral incision is safe and feasible for esophageal cancer associated with coronary artery disease

Controversy still exists as to whether surgical treatment has any impact on the long-term survival of esophageal cancer (EC) patients with coronary artery disease treated with curative esophagectomy combined with off-pump coronary artery bypass grafting (OPCABG). Therefore, the aim of this study was to introduce and assess the effect of esophagectomy combined with OPCABG on both short- and long-term outcomes. From January 2010 to January 2015, 1428 EC or esophagogastric junction cancer patients underwent surgical treatment at Henan Chest Hospital, Zhengzhou, China. The clinical data of 25 patients who underwent EC resection through a left thoracotomy following OPCABG and the perioperative characteristics and follow-up results were analyzed. The majority of the patients were male, and the EC stage was predominantly cT2N0-1M0 II. The most common pathological types were squamous cell carcinoma. The EC surgeries consisted of 15 chest anastomosis procedures and 10 cervical anastomosis procedures with aortocoronary graft implantation (mean: 2.36 grafts per patient). The mean total operative time was 330.8 ± 83.5 minutes. The median intensive care unit and hospital lengths of stay were 1.72 and 21.16 days, respectively. Resection without macroscopic residual disease (R0) was achieved in all of the patients. The most frequent complications included pulmonary infections (24%), arrhythmias (24%), pleural effusion (12%), and esophageal anastomotic leakage (8%). There were no postoperative deaths or myocardial infarctions within 30 days after the surgery. The overall 1-, 3-, and 5-year survival rates were 88%, 40%, and 24%, respectively, with a median survival time of 43 months. In the short-term, radical resection of EC following OPCABG is a safe and feasible treatment with low postoperative mortality rates. In the long-term, simultaneous surgery is acceptable and is associated with favorable overall and disease-free survival.

Prophylaxis Against Thromboembolic Events During Chemotherapy for Germ Cell Cancer

INTRODUCTION

Patients with advanced germ cell tumors (GCT) receiving cisplatin-based chemotherapy have high rates of thromboembolic events (TEE) which can negatively affect their overall survival. While primary TEE prophylaxis during chemotherapy may prevent these events, it is unclear which patients will benefit in this setting.

MATERIALS AND METHODS

A review of PubMed/Medline was conducted in December 2020 and all pertinent articles were evaluated for relevancy and quality of data for inclusion in the review.

RESULTS

Studies on patients receiving initial cisplatin-based chemotherapy for advanced GCT have reported up to a 19% rate of TEE. This high rate may be associated with multiple factors including retroperitoneal lymphadenopathy, advanced clinical stage, high risk Khorana scores and presence of a central line. Large phase III clinical trials have demonstrated the benefit of low-molecular-weight-heparin and direct oral anticoagulants for primary prophylaxis and against recurrent TEE. However, primary prophylaxis is currently underutilized with GCT patients starting chemotherapy.

CONCLUSION

Precise models to predict TEE risk and consideration of anticoagulation are difficult to develop owing to the relatively uncommon nature of GCT and lack of representation in primary TEE prophylaxis clinical trials. Despite these limitations, we believe that the benefits of prophylactic anticoagulation outweigh the risk of major bleeding in select GCT patients with higher risk of TEE. We have developed a simple algorithm to help guide TEE prophylaxis selection based on patient factors and route of chemotherapy administration. Given the high rate of TEE in GCT patients, we believe better utilization of primary prophylaxis in patient starting cisplatin-based chemotherapy will have clinical benefit.

Risk of major bleeding associated with concomitant use of anticancer drugs and direct oral anticoagulant in patients with cancer and atrial fibrillation

This study evaluated the risk of major bleeding associated with concomitant use of direct oral anticoagulant (DOAC) and anticancer drugs (ACDs), which share metabolic pathways, in patients with atrial fibrillation (AF) and cancer. We performed a retrospective cohort study using Taiwan's National Health Insurance database and included patients with AF and cancer who received DOAC prescriptions from 1 to 2012 to 31 December 2017. The incidence of major bleeding in person-quarters with concomitant use of DOAC and any of 15 ACDs with inhibitory or competitive effects of CYP3A4 or P-gp activity (docetaxel, vinorelbine, methotrexate, irinotecan, etoposide, doxorubicin, cyclophosphamide, imatinib, nilotinib, abiraterone, bicalutamide, tamoxifen, anastrozole, cyclosporine, tacrolimus) was compared with that in person-quarters with DOAC alone. Adjusted incidence-rate differences between DOAC use with and without concurrent ACDs were estimated using Poisson regression models weighted by the inverse probability of treatment. In 13,158 patients with AF and cancer (76.9 ± 8.9 years; male 60%), 1545 major bleeding events occurred during 90,540 DOAC-exposed person-quarters. Concurrent use of DOAC and any of 15 ACDs occurred in only 18% of patients. Compared with use of DOAC alone, concomitant use of DOAC and these ACDs was not associated with an increased risk of major bleeding. Co-medication with DOAC and ACDs with inhibitory or competitive effects on CYP3A4 or P-gp activity was not associated with a higher risk of major bleeding than DOAC alone. Our findings may provide clinicians with confidence regarding the safety of concurrent use of DOAC and ACDs in patients with AF and cancer.

Estimating Bleeding Risk in Patients with Cancer-Associated Thrombosis: Evaluation of Existing Risk Scores and Development of a New Risk Score

BACKGROUND

 Bleeding risk is highly relevant for treatment decisions in cancer-associated thrombosis (CAT). Several risk scores exist, but have never been validated in patients with CAT and are not recommended for practice.

OBJECTIVES

 To compare methods of estimating clinically relevant (major and clinically relevant nonmajor) bleeding risk in patients with CAT: (1) existing risk scores for bleeding in venous thromboembolism, (2) pragmatic classification based on cancer type, and (3) new prediction model.

METHODS

 In a posthoc analysis of the Hokusai VTE Cancer study, a randomized trial comparing edoxaban with dalteparin for treatment of CAT, seven bleeding risk scores were externally validated (ACCP-VTE, HAS-BLED, Hokusai, Kuijer, Martinez, RIETE, and VTE-BLEED). The predictive performance of these scores was compared with a pragmatic classification based on cancer type (gastrointestinal; genitourinary; other) and a newly derived competing risk-adjusted prediction model based on clinical predictors for clinically relevant bleeding within 6 months after CAT diagnosis with nonbleeding-related mortality as the competing event ("CAT-BLEED").

RESULTS

 Data of 1,046 patients (149 events) were analyzed. Predictive performance of existing risk scores was poor to moderate (C-statistics: 0.50-0.57; poor calibration). Internal validation of the pragmatic classification and "CAT-BLEED" showed moderate performance (respective C-statistics: 0.61; 95% confidence interval [CI]: 0.56-0.66, and 0.63; 95% CI 0.58-0.68; good calibration).

CONCLUSION

 Existing risk scores for bleeding perform poorly after CAT. Pragmatic classification based on cancer type provides marginally better estimates of clinically relevant bleeding risk. Further improvement may be achieved with "CAT-BLEED," but this requires external validation in practice-based settings and with other DOACs and its clinical usefulness is yet to be demonstrated.

Management of Cancer-Associated Thrombosis: Unmet Needs and Future Perspectives

Patients with cancer are at a high risk of symptomatic venous thromboembolism (VTE), which is a common cause of morbidity and mortality in this patient population. Increased risk of recurrent VTE and bleeding complications are two major challenges associated with therapeutic anticoagulation in these patients. Long-term therapy with low-molecular-weight heparins (LMWHs) has been the standard of care for the treatment of cancer-associated VTE given its favorable risk–benefit ratio in comparison with vitamin K antagonists. Direct oral anticoagulants (DOACs), which offer the convenience of oral administration and have a rapid onset of action, have recently emerged as a new treatment option for patients with cancer-associated thrombosis (CT). Randomized clinical trial data with head-to-head comparisons between DOACs and LMWHs showed that overall, DOACs have a similar efficacy profile but a higher risk of bleeding was observed in some of these studies. This review aims to identify unmet needs in the treatment of CT. We discuss important considerations for clinicians tailoring anticoagulation (1) drug–drug interactions, (2) risk of bleeding (e.g., gastrointestinal bleeding), (3) thrombocytopenia, hematological malignancies, (4) metastatic or primary brain tumors, and (5) renal impairment. Additional research is warranted in several clinical scenarios to help clinicians on the best therapeutic approach.

How I treat and prevent venous thrombotic complications in patients with lymphoma

Venous thromboembolism (VTE) is a common complication occurring in 5-10% of patients with lymphoma. As the complexity of lymphoma management has increased with novel therapies, so too has the treatment of VTE. Therapeutic options for the treatment of cancer-associated VTE have expanded from only warfarin and low-molecular-weight heparins (LMWHs) to include the direct oral anticoagulants (DOACs) apixaban, edoxaban and rivaroxaban. There have been no head-to-head trials comparing different DOACs in this setting and randomized trials comparing a DOAC with LMWH dalteparin differ in trial design and results. Drug-drug interactions, drug-specific side effects and patient selection are important considerations when prescribing anticoagulant therapy. In all patients, the relative risks of thrombosis and bleeding, the availability of the anticoagulant, and the life expectancy of the patient are vital elements in selecting the most appropriate anticoagulant (which can vary over time) for the individual patient. We describe the intricacies and challenges of treating thrombotic complications in patients with lymphoma with an emphasis on evidence and guideline-based care.

A comprehensive review of DOACs for cancer associated VTE prophylaxis or treatment

Cancer is a leading cause of venous thromboembolism (VTE), which contributes to significant morbidity and mortality in these patients. Increased thrombotic risk in cancer patients is modified by tumor-specific biology, disease-directed interventions, and individual comorbidities. Risk stratification for prophylaxis and treatment requires regular reevaluation of these factors, which can be facilitated by validated prediction tools. This review also discusses large clinical trial data (SELECT-D, HOKUSAI-VTE, ADAM VTE, CARAVAGGIO) demonstrating that direct oral anticoagulants (DOACs) are effective in the treatment of cancer-associated VTE, with comparable efficacy to the traditional choice of low molecular weight heparin. In the prophylactic setting derived from patients with cancer with increased VTE risk, DOACs also reduced the incidence of VTE with only modest increases in bleeding risk. The ease of DOAC administration and acceptable risk profile in the carefully selected patient make them an appealing choice for anticoagulation. In instances where the risk of gastrointestinal bleeding is of concern, apixaban, in particular, may still be a suitable option in place of LMWH. These improvements in our anticoagulation approach to cancer-associated VTE are well-timed to accompany the recent advances in disease-directed therapies that are enabling patients to live longer with cancer and therefore at increased risk of complications such as VTE.

Characteristics and outcomes of patients on concurrent direct oral anticoagulants and targeted anticancer therapies-TacDOAC registry: Communication from the ISTH SSC Subcommittee on Hemostasis and Malignancy

BACKGROUND

Cancer patients are increasingly prescribed direct oral anticoagulants (DOACs) and targeted anticancer therapies, but limited data are available on the outcomes during concurrent use.

OBJECTIVES

We conducted an international registry through the Scientific and Standardization Committee of the ISTH to evaluate the characteristics, bleeding, and thrombotic outcomes in patients receiving concurrent DOACs and targeted anticancer therapies.

PATIENTS/METHODS

Patients receiving concurrent DOACs for venous thromboembolism (VTE) or atrial fibrillation and selected targeted anticancer therapies were followed for 6 months after the start of concurrent use. Data including patient and cancer characteristics, major bleeding, non-major bleeding events, and venous or arterial thromboses were collected.

RESULTS

Two hundred and two patients were included from six institutions in the United States and Israel. The most common malignancies were hematologic (N = 57, 28.2%), followed by breast (N = 50, 24.8%) and lung (N = 44, 21.8%). The most common anticancer therapies were epidermal growth factor receptor (EGFR) and anaplastic lymphoma kinase (ALK) inhibitors (N = 43, 21.3%), followed by Bruton's tyrosine kinase (BTK) inhibitors (N = 42, 20.8%) and palbociclib (N = 42, 20.8%). During follow-up, there were 9 major bleeding and 12 non-major bleeding events, corresponding to cumulative incidences of 4% (95% confidence interval [CI]: 2-8%) and 6% (95% CI: 3-10%), respectively. The cumulative incidence of major bleeding events was highest in BTK inhibitor users (10%). There were 3 VTE and 2 arterial thromboses, corresponding to cumulative incidences of 1.5% (95% CI: 0.4-4.0%) and 1.0% (95% CI: 0.2-3.3%), respectively.

CONCLUSIONS

In this cohort receiving concurrent DOACs and targeted anticancer therapies, the incidence of bleeding is higher compared to thrombosis, particularly with BTK inhibitors. Future larger prospective studies are needed.

Infigratinib is a Reversible Inhibitor and Mechanism-based Inactivator of Cytochrome P450 3A4

Infigratinib (INF) is a promising selective inhibitor of fibroblast growth factor receptors 1-3 that has recently been accorded both orphan drug designation and priority review status by the U.S Food and Drug Administration for the treatment of advanced cholangiocarcinoma. Its propensity to undergo bioactivation to electrophilic species was recently expounded upon. However, other than causing aberrant idiosyncratic toxicities, these reactive intermediates may elicit mechanism-based inactivation (MBI) of cytochrome P450 enzymes (CYP450). In this study, we investigated the interactions between INF and the most abundant hepatic cytochrome P450 3A4 (CYP3A4). Our findings revealed that apart from being a potent noncompetitive reversible inhibitor of CYP3A4, INF inactivated CYP3A4 in a time-, concentration- and NADPH-dependent manner with K _I, k _inact and partition ratio of 2.45 µM, 0.053 min^-1 and 41 respectively when rivaroxaban was employed as the probe substrate. Co-incubation with testosterone (alternative CYP3A substrate) or ketoconazole (direct CYP3A inhibitor) attenuated the rate of inactivation whereas the inclusion of glutathione and catalase did not confer such protection. The lack of enzyme activity recovery following dialysis for 4 hours and oxidation with potassium ferricyanide, coupled with the absence of the characteristic Soret peak signature collectively substantiated that inactivation of CYP3A4 by INF was not mediated by the formation of quasi-irreversible metabolite-intermediate complexes but rather through irreversible covalent adduction to the prosthetic heme and/or apoprotein. Finally, glutathione trapping and high-resolution mass spectrometry experimental results unravelled two plausible bioactivation mechanisms of INF arising from the generation of a p-benzoquinone diimine and epoxide reactive intermediate. Significance Statement The potential of infigratinib (INF) to cause mechanism-based inactivation (MBI) of CYP3A4 was unknown. We report the reversible noncompetitive inhibition and irreversible covalent MBI of CYP3A4 by INF and proposed two potential bioactivation pathways implicating p-benzoquinone diimine and epoxide reactive intermediates. Findings from this study lay the groundwork for future investigation of clinically-relevant drug-drug interactions between INF and concomitant substrates of CYP3A4.

Mechanism-Based Inactivation of Cytochrome P450 3A4 and 3A5 by the Fibroblast Growth Factor Receptor Inhibitor Erdafitinib

Erdafitinib (ERD) is a first-in-class pan inhibitor of fibroblast growth factor receptor 1-4 that has garnered global regulatory approval for the treatment of advanced or metastatic urothelial carcinoma. Although it has been previously reported that ERD elicits time-dependent inhibition (TDI) of cytochrome P450 (P450) 3A4 (CYP3A4), the exact biochemical nature underpinning this observation remains obfuscated. Moreover, it is also uninterrogated if CYP3A5-its highly homologous counterpart-could be susceptible to such interactions. Mechanism-based inactivation (MBI) of P450 is a unique subset of TDI that hinges on prior bioactivation of the drug to a reactive intermediate and possesses profound clinical and toxicological implications due to its irreversible nature. Here, we investigated and confirmed that ERD inactivated both CYP3A isoforms in a time-, concentration-, and NADPH-dependent manner with K_I, k_inact, and partition ratio of 4.01 and 10.04 μM, 0.120 and 0.045 min^-1, and 32 and 55 for both CYP3A4 and CYP3A5, respectively, when rivaroxaban was employed as the probe substrate. Co-incubation with an alternative substrate or direct inhibitor of CYP3A attenuated the rate of inactivation, whereas the addition of glutathione or catalase did not induce such protection. The lack of enzyme activity recovery following dialysis for 4 h and oxidation with potassium ferricyanide combined with the lack of a Soret peak in spectral scans collectively substantiated that ERD is an irreversible covalent MBI of CYP3A. Finally, glutathione trapping and high-resolution mass spectrometry experiments illuminated a plausible bioactivation mechanism of ERD by CYP3A arising from metabolic epoxidation of its quinoxaline ring.

Thrombosis in hematological malignancies: mechanisms and implications

A B S T R A C T Thrombotic events are a major cause of morbidity and mortality in cancer. While the association of venous thromboembolic events with cancer is well documented, in recent years arterial events (i.e. acute myocardial infarction and ischemic strokes) have also emerged as relatively common complications among cancer patients. In hematological malignancies incorporating a heterogeneous group of diseases, the prediction of thrombosis occurrence and/or recurrence is challenging, due to unique disease characteristics. Furthermore, the treatment of thrombosis in these patients is often complicated because of disease- or therapy-related thrombocytopenia. In addition, patients with hematological cancers are poorly represented in randomized control clinical trials; hence, evidence-based guidelines are limited. This review will discuss the incidence of venous and arterial thrombotic events in common myeloid and lymphoproliferative diseases. Several new mechanisms contributing to cancer- associated thrombosis will be elaborated. The complicated issue of risk assessment and management of venous thrombosis in patients with hematological malignancies will be delineated.

Potential Dexamethasone-Direct Oral Anticoagulant Drug Interaction: Is This a Concern in COVID?

OBJECTIVE

To evaluate the literature on a potential dexamethasone-direct oral anticoagulant (DOAC) drug interaction and provide management considerations with COVID hypercoagulability.

DATA SOURCES

A search of EMBASE, PubMed, and Google Scholar (January 1990 to May 2021), limited to the English language, using applicable search terms resulted in 137 articles, with 21 relevant articles included. Regulatory agency and clinical guidance documents were also reviewed.

STUDY SELECTION AND DATA EXTRACTION

Included articles describe in vitro or in vivo animal or human data for dexamethasone induction of cytochrome P450 (CYP) 3A4 or P-glycoprotein (P-gp).

DATA SYNTHESIS

Dexamethasone has the potential to interact with the DOACs via CYP3A4 and/or P-gp induction. Only apixaban and rivaroxaban have CYP3A4 metabolism. Dexamethasone can increase CYP3A4 activity by up to 70% and reduce the area under the concentration-time curve (AUC) of CYP3A4 substrates by >40%, which is consistent with criteria for a weak CYP inducer. In rodents, dexamethasone P-gp induction is associated with AUC reductions of 20% to 50%. Human data are lacking.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Severe COVID-19 infection is associated with hypercoagulability. Although heparins are the preferred anticoagulants for hospitalized COVID-19 patients, DOACs are being utilized. Dexamethasone is recommended for hospitalized COVID-19 patients requiring supplemental oxygen. The concurrent use of dexamethasone and apixaban or rivaroxaban in such patients carries the potential for reduced anticoagulant effect during a state of heightened thrombotic risk.

CONCLUSIONS

Concurrent use of dexamethasone and apixaban or rivaroxaban in hospitalized COVID-19 patients with laboratory evidence of COVID coagulopathy should be avoided until higher-quality data are available.

Cancer and atrial fibrillation: Epidemiology, mechanisms, and anticoagulation treatment

Cancer patients are at an increased risk of developing atrial fibrillation (AF) and thrombosis. However, the management of anticoagulation in patients with both diseases may be challenging, and data on these patients are lacking. We summarize the current evidence on the incidence and prevalence of cancer in AF and vice versa and provide some practical considerations on the management of oral anticoagulation in specific clinical situations. Low-molecular weight heparins are not approved for thromboprophylaxis in AF, and management of warfarin can be difficult. The use of direct oral anticoagulants may be particularly attractive for their rapid onset/offset action and lower bleeding risk.

The cancer patient and cardiology

Advances in cancer treatments have improved clinical outcomes, leading to an increasing population of cancer survivors. However, this success is associated with high rates of short- and long-term cardiovascular (CV) toxicities. The number and variety of cancer drugs and CV toxicity types make long-term care a complex undertaking. This requires a multidisciplinary approach that includes expertise in oncology, cardiology and other related specialties, and has led to the development of the cardio-oncology subspecialty. This paper aims to provide an overview of the main adverse events, risk assessment and risk mitigation strategies, early diagnosis, medical and complementary strategies for prevention and management, and long-term follow-up strategies for patients at risk of cancer therapy-related cardiotoxicities. Research to better define strategies for early identification, follow-up and management is highly necessary. Although the academic cardio-oncology community may be the best vehicle to foster awareness and research in this field, additional stakeholders (industry, government agencies and patient organizations) must be involved to facilitate cross-discipline interactions and help in the design and funding of cardio-oncology trials. The overarching goals of cardio-oncology are to assist clinicians in providing optimal care for patients with cancer and cancer survivors, to provide insight into future areas of research and to search for collaborations with industry, funding bodies and patient advocates. However, many unmet needs remain. This document is the product of brainstorming presentations and active discussions held at the Cardiovascular Round Table workshop organized in January 2020 by the European Society of Cardiology.

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.

Drug-drug interaction (DDI) with direct oral anticoagulant (DOAC) in patients with cancer

Cancer-associated thrombosis (CAT) is the second leading cause of death in cancer patients after tumor progression. The treatment of CAT is challenging because of a high risk of VTE recurrence, a high risk of bleeding, common presence of comorbidities, poly-medication, and potential drug-drug interactions (DDI). Since 2018, direct oral anticoagulants (DOACs) represent a promising therapeutic alternative and have been recently included into the 2019 update of the International Initiative on Thrombosis and Cancer (ITAC-CME) clinical practice guidelines for management of CAT. However, pharmacokinetic studies suggest that concomitant treatment with P-gp or CYP3A4 inhibitors will result in an increased exposure to rivaroxaban and apixaban, but the clinical relevance of these studies is unknown. In addition, there is an important inter-individual variability in drug absorption, distribution, metabolism and elimination, even more in cancer patients. Overall, the risk of pharmacokinetic DDI should be estimated based on several individual (patient age, renal and liver function, number of comedications) and diseases-related factors, including inflammation, sarcopenia, and low body weight. In this context, DDI with clinical implications could be expected with anti-neoplastic agents or supportive care treatments, especially with drugs known to be moderate or strong inhibitors/inducers of CYP3A4 and P-gp. Consequently, in the presence of potential DDIs through CYP3A4, and/or P-gp, LMWHs remain the first-line anticoagulant of choice for the long-term treatment of CAT. Multidisciplinary consultation meetings and therapeutic patient education should be emphasized in the complex management of CAT.

Treatment of cancer-associated thrombosis: The evolution of anticoagulant choice and clinical insights into practical management

Low-molecular-weight heparin (LMWH) therapy is recommended over vitamin K antagonists (VKAs) for the treatment of cancer-associated thrombosis (CAT) and extended therapy is recommended in those with active cancer to prevent recurrent thrombosis. However, the inconvenience of daily subcutaneous injections and the cost of LMWH therapy hinder long-term use. Observational data demonstrate that persistence with LMWH therapy is low in clinical practice and that many patients are switched to oral alternatives - namely VKAs and direct oral anticoagulants (DOACs). Recently, the efficacy and safety of apixaban, edoxaban, and rivaroxaban versus LMWH therapy for the treatment of CAT have been demonstrated in randomized trials. This review provides a critical evaluation of studies with DOACs in this setting and an update on the guidance regarding anticoagulant use for the treatment of CAT. In recognition of the heterogeneity of patients with cancer and the challenges of CAT, patient cases with expert clinical perspectives are presented.

[Treatment recommendations in cardio-oncology: where are we?]

This article provides an overview of current prevention and treatment options for typical cardiovascular side effects of oncological therapies as well as cardiovascular complications of malignant disease. Focus is put on the prevention and treatment of heart failure under potentially cardiotoxic cancer therapies. In addition, current options for the treatment of common venous thromboembolism in cancer patients will be discussed.

Evaluation of the efficacy and safety of apixaban and rivaroxaban in cancer patients receiving concomitant active anti-neoplastic therapy at an outpatient cancer setting

Introduction

Venous thromboembolism is a common complication among cancer patients with an estimated risk of 20%. American Society of Clinical Oncology guidelines recommend direct oral anticoagulants for long-term anticoagulation but caution the use of direct oral anticoagulants because of drug–drug interactions with antineoplastic therapies. The clinical impact of these drug–drug interactions is yet to be studied in clinical trials. This study aims to evaluate the effect of the drug–drug interactions on venous thromboembolism recurrence and bleeding.

Methods

This is a retrospective cohort study that included cancer patients with venous thromboembolism receiving apixaban or rivaroxaban with antineoplastic therapy. The impact of the drug–drug interaction was determined by its effect on the rates of venous thromboembolism recurrence and bleeding in patients with a drug–drug interaction compared to patients with no drug–drug interaction.

Results

The primary composite endpoint of venous thromboembolism recurrence and bleeding events occurred in 65% versus 62% of patients in drug–drug interaction and non-drug–drug interaction groups accordingly. There was a higher rate of venous thromboembolism recurrence and minor bleeding events with anti-mitotic microtubule inhibitors and a higher rate of minor bleeding events with hormonal therapy and alkylating agents. Among the drug–drug interaction group, there were no major bleeding events reported with mild drug–drug interactions when compared to moderate-to-severe drug–drug interactions. There was no difference in time to venous thromboembolism recurrence between rivaroxaban and apixaban.

Conclusion

Due to small sample size, our study results could not confirm a higher risk of bleeding or venous thromboembolism recurrence with the drug–drug interactions. Further prospective study is warranted, but clinicians should be aware of these drug–drug interactions and identify them using available literature.