Pharmacological cancer treatment and venous thromboembolism risk

Underlying Mechanisms of Thrombosis Associated with Cancer and Anticancer Therapies

OPINION STATEMENT

Cancer-associated thrombosis (CAT) has been identified as the second most prevalent cause of death after cancer itself. Moreover, the risk of thrombotic events in cancer patients increases due to anticancer drugs, such as tyrosine kinase inhibitors (TKIs). Venous thromboembolism (VTE) as well as arterial thromboembolic (ATE) events are present in CAT. Although VTE occurs more frequently, ATE events are very significant and in some cases are more dangerous than VTE. Guidelines for preventing thrombosis refer mainly VTE as well as the contribution of ATE events. Several factors are involved in thrombosis related to cancer, but the whole pathomechanism of thrombosis is not clear and may differ between patients. The activation of the coagulation system and the interaction of cancer cells with other cells including platelets, endothelial cells, monocytes, and neutrophils are promoted by a hypercoagulable state caused by cancer. We present an update on the pathomechanisms of CAT and the effect of anticancer drugs, mainly targeted therapies with a focus on TKIs. Considering the risk of bleeding associated with anticoagulation in each cancer patient, the anticoagulation strategy may involve the use of FXIa inhibitors, direct oral anticoagulants, and low-molecular-weight heparin. Further research would be valuable in developing strategies for reducing CAT.

Lung Cancer Related Thrombosis (LCART): Focus on Immune Checkpoint Blockade

Cancer-associated thrombosis (CAT) is a common complication in lung cancer patients. Lung cancer confers an increased risk of thrombosis compared to other solid malignancies across all stages of the disease. Newer treatment agents, including checkpoint immunotherapy and targeted agents, may further increase the risk of CAT. Different risk-assessment models, such as the Khorana Risk Score, and newer approaches that incorporate genetic risk factors have been used in lung cancer patients to evaluate the risk of thrombosis. The management of CAT is based on the results of large prospective trials, which show similar benefits to low-molecular-weight heparins (LMWHs) and direct oral anticoagulants (DOACs) in ambulatory patients. The anticoagulation agent and duration of therapy should be personalized according to lung cancer stage and histology, the presence of driver mutations and use of antineoplastic therapy, including recent curative lung surgery, chemotherapy or immunotherapy. Treatment options should be evaluated in the context of the COVID-19 pandemic, which has been shown to impact the thrombotic risk in cancer patients. This review focuses on the epidemiology, pathophysiology, risk factors, novel predictive scores and management of CAT in patients with active lung cancer, with a focus on immune checkpoint inhibitors.

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.

Ambulatory cancer patients: who should definitely receive antithrombotic prophylaxis and who should never receive

Up to 15-20% of cancer patients experience one or more episodes of venous thromboembolism during cancer disease. Approximately 80% of all cancer-associated venous thromboembolic events occur in non-hospitalized patients. Routine thromboprophylaxis for outpatients with cancer who start new anticancer treatment is currently not recommended by the international guidelines due to the high heterogeneity of these patients in terms of VTE or bleeding risks, the difficulties in selecting patients at high risk, and the uncertainty of duration of prophylaxis. Although the international guidelines endorsed the Khorana score for estimating the thrombotic risk in ambulatory cancer patients, the discriminatory performance of this score is not completely convincing and varies according to the cancer type. Consequently, a minority of ambulatory patients with cancer receive an accurate screening for primary prophylaxis of VTE. The aim of this review is to provide support to physicians in identifying those ambulatory patients with cancer for whom thromboprophylaxis should be prescribed and those that should not be candidate to thromboprophylaxis. In absence of high bleeding risk, primary thromboprophylaxis should be recommended in patients with pancreatic cancer and, probably, in patients with lung cancer harboring ALK/ROS1 translocations. Patients with upper gastrointestinal cancers are at high risk of VTE, but a careful assessment of bleeding risk should be made before deciding on antithrombotic prophylaxis. Primary prevention of VTE is not recommended in cancer patients at increased risk of bleeding as patients with brain cancer, with moderate-to-severe thrombocytopenia or severe renal impairment.

Unmet clinical needs in the prevention and treatment of cancer-associated venous thromboembolism

Venous thromboembolism (VTE), which includes pulmonary embolism and deep vein thrombosis, is a leading cause of morbidity and mortality in patients with cancer. Based on accumulating evidence, the prophylaxis and treatment of cancer-associated VTE have been changed over the years. Recently, the introduction in clinical practice of the direct oral anticoagulants has radically changed the management of cancer-associated VTE for their easier use and non-inferior efficacy-safety profile compared to low-molecular-weight heparins. However, the heterogeneity of the cancer population in terms of site, type and stage of the malignancy, the presence of comorbidities, and the variability in cancer treatment and prognosis represent major challenges in the management of VTE in patients with cancer. In the present review, we will discuss clinical questions that represent unsolved issues in the setting of cancer-associated VTE and provide an overview on recent evidence on this topic: primary prophylaxis in ambulatory cancer patients treated with chemotherapy and in cancer surgical patients, need of long-term anticoagulation in cancer patients, treatment of VTE in cancer patients at increased bleeding risk and in special categories such as incidental VTE, splanchnic vein thrombosis or catheter-related thrombosis.

Bleeding risk with concomitant administration of VEGF-TKIs and anticoagulant agents

Anti-cancer treatment is considered an independent risk factor for emergent bleeding during anticoagulant treatment in patients with cancer-associated thrombosis. This increased bleeding risk is perceived as major concern particularly when tyrosine kinase inhibitors (TKIs) targeting the vascular endothelial derived growth factor receptor (VEGFR-TKIs) are co-administered with anticoagulants. We evaluated the effects of the combined administration of a VEGF-TKI and the oral direct anticoagulant (apixaban) or the low-molecular weight-heparin dalteparin in a sub-analysis of the Caravaggio study in patients with a diagnosis of cancer patients with venous thromboembolism. The rate of major bleeding was 4.2% in the 668 patients who received any type of anti-cancer treatment and 3.5% in the 487 patients who did not receive any anti-cancer treatment. The relative risk for patients treated with a VEGF-TKI was 1.58 (95% CI: 0.69-3.68), compared to patients treated with anticancer agents other than a VEGF-TKI and 1.73 (95% CI: 0.73-4.07) compared to patients who did not receive any anticancer treatment. The administration of a VGEF-TKI did not have any impact on the recurrence rate of venous thromboembolism. We observed a numerically not statistically significant increase in major bleeding events in patients on concurrent VEGF-TKI and therapeutic anticoagulation with no excess in those who received apixaban. Further prospective well-designed studies are needed to evaluate whether the concomitant administration of VGEF-TKI and anticoagulant agents may result in an increase of bleeding in patients with a diagnosis of cancer treated for venous thromboembolism.

The Acute and Chronic Effects of Resistance and Aerobic Exercise in Hemostatic Balance: A Brief Review

Hemostatic balance refers to the dynamic balance between blood clot formation (coagulation), blood clot dissolution (fibrinolysis), anticoagulation, and innate immunity. Although regular habitual exercise may lower the incidence of cardiovascular diseases (CVD) by improving an individual’s hemostatic profile at rest and during exertion, vigorous exercise may increase the risk of sudden cardiac death and venous thromboembolism (VTE). This literature review aims to investigate the hemostatic system’s acute and chronic adaptive responses to different types of exercise in healthy and patient populations. Compared to athletes, sedentary healthy individuals demonstrate similar post-exercise responses in platelet function and coagulatory and fibrinolytic potential. However, hemostatic adaptations of patients with chronic diseases in regular training is a promising field. Despite the increased risk of thrombotic events during an acute bout of vigorous exercise, regular exposure to high-intensity exercise might desensitize exercise-induced platelet aggregation, moderate coagulatory parameters, and up-regulate fibrinolytic potential via increasing tissue plasminogen activator (tPA) and decreasing plasminogen activator inhibitor (PAI-1) response. Future research might focus on combining different types of exercise, manipulating each training characteristic (frequency, intensity, time, and volume), or investigating the minimal exercise dosage required to maintain hemostatic balance, especially in patients with various health conditions.

Venous thromboembolism in cancer and cancer immunotherapy

Venous thromboembolism (VTE) is a clinical disease that includes deep vein thrombosis and pulmonary embolism. Amongst its underlying risk factors, cancer is of great importance. Stasis, endothelial injury, and hypercoagulability result in clot formation and VTE. Cancer can affect coagulability by favoring these three factors, resulting in VTE incidence. Immunotherapy is a novel therapeutic approach, targeting cancer by immune system enhancement. VTE is one of the most important adverse effects of immunotherapy, which complicates the administration of immunotherapy in cancer patients. The current review provides a brief overview of VTE epidemiology, pathophysiology, risk factors, biomarkers, the relationship of cancer and cancer immunotherapy to VTE incidence, and managing cancer-associated VTE.

Safety Assessment on Serious Adverse Events of Targeted Therapeutic Agents Prescribed for RAS Wild-Type Metastatic Colorectal Cancer: Systematic Review and Network Meta-Analysis

Despite substantially elevated risk of serious adverse events (SAEs) from targeted therapy in combination with chemotherapy, comprehensive pharmacovigilance research is limited. This study aims to systematically assess SAE risks of commonly prescribed targeted agents (bevacizumab, cetuximab, and panitumumab) in patients with rat sarcoma viral oncogene homolog (RAS) wild-type metastatic colon cancer. Keyword searches of Cochrane Library, Clinical Key and MEDLINE were conducted per PRISMA-NMA guidelines. Frequentist network meta-analysis was performed with eight randomized controlled trials to compare relative risk (RR) of 21 SAE profiles. The risks of hematological, gastrointestinal, neurological SAE were insignificant among targeted agents (p > 0.05). The risk of serious hypertension was substantially elevated in bevacizumab-based chemotherapy (p < 0.05), whereas panitumumab-based chemotherapy had markedly elevated risk of serious thromboembolism (RR 3.65; 95% CI 1.30−10.26). Although both cetuximab and panitumumab demonstrated increased risk of serious dermatological and renal toxicities, panitumumab-based chemotherapy has relatively higher risk of skin toxicity (RR 15.22; 95% CI 7.17−32.35), mucositis (RR 3.18; 95% CI 1.52−6.65), hypomagnesemia (RR 20.10; 95% CI 5.92−68.21), and dehydration (RR 2.81; 95% CI 1.03−7.67) than cetuximab-based chemotherapy. Thus, further studies on risk stratification and SAE management are warranted for safe administration of targeted agents.

Cancer-Associated ThrOmboSIs - Patient-Reported OutcoMes With RivarOxaban (COSIMO) - Baseline characteristics and clinical outcomes

BACKGROUND

Patients with cancer-associated thrombosis (CAT) have a high risk of recurrent venous thromboembolic events, which contribute to significant morbidity and mortality. Direct oral anticoagulants may provide a convenient treatment option for these patients.

OBJECTIVES

To assess clinical characteristics and outcomes of patients with active cancer changing to rivaroxaban after ≥4 weeks of standard therapy for the treatment of venous thromboembolism (VTE) in clinical practice. This analysis focused on secondary outcomes of Cancer-associated thrOmboSIs - Patient-reported outcoMes with rivarOxaban (COSIMO).

PATIENTS

COSIMO was a multinational, prospective, noninterventional, single-arm cohort study. Overall, 505 patients received at least one dose of rivaroxaban; 96.6% changing from low-molecular-weight heparin, 1.6% from a vitamin K antagonist, and 1.8% from fondaparinux.

RESULTS

Most patients had solid tumors (n = 449; 88.9%) and approximately half of these patients had metastases. The qualifying venous thromboembolic event was deep vein thrombosis (DVT) in 45.3% of patients, pulmonary embolism (PE) in 37.2% of patients, DVT with PE in 9.7% of patients, and catheter-associated DVT in 7.5% of patients. Approximately 75.1% of patients received rivaroxaban for at least 3 months; 150 (29.7%) patients received concomitant chemotherapy during the study. VTE recurrence, major bleeding, nonmajor bleeding, and major adverse cardiovascular events occurred in 18 (3.6%), 18 (3.6%), 81 (16.0%), and 12 (2.4%) patients, respectively.

CONCLUSIONS

In patients with CAT who changed to rivaroxaban treatment after ≥4 weeks of standard therapy, the observed incidence proportions of recurrent VTE and bleeding events were in keeping with the recognized effectiveness and safety profile of rivaroxaban for the treatment of CAT.

Effects of concomitant administration of anticancer agents and apixaban or dalteparin on recurrence and bleeding in patients with cancer-associated venous thromboembolism

BACKGROUND

Whether concomitant administration of anticancer agents influences the efficacy and safety of oral anticoagulants in patients treated for cancer-associated venous thromboembolism (VTE) is undefined. The pharmacological interaction between anticancer agents and direct oral anticoagulants is perceived as a concern.

METHODS

We evaluated the effects of concomitant administration of anticancer agents on recurrent VTE, major bleeding and death in patients with cancer-associated VTE randomised to receive apixaban or dalteparin in the Caravaggio study.

RESULTS

Anticancer agents were concomitantly given to 336 patients (58.3%) treated with apixaban and to 332 patients (57.3%) treated with dalteparin. In patients treated with apixaban, recurrent VTE occurred in 20 (6.0%) and 12 (5.0%) among patients treated or not treated with anticancer agents, respectively (hazard ratio [HR] = 1.14; 0.55-2.38); major bleeding occurred in 12 (3.6%) and 10 (4.2%) patients , respectively (HR = 0.79; 0.34-1.82), and death occurred in 74 (22.0%) and 61 (25.4%) patients , respectively (HR = 0.71; 0.51-1.00). In patients treated with dalteparin, recurrent VTE occurred in 24 (7.2%) and 22 (8.9%) among patients treated or not treated with anticancer agents, respectively (HR = 0.71; 0.40-1.28); major bleeding occurred in 16 (4.8%) and 7 (2.8%) patients, respectively (HR = 1.78; 0.66-4.79), and death occurred in 87 (26.2%) and 66 (26.7%) patients, respectively (HR = 0.85; 0.62-1.18). The comparative efficacy and safety of apixaban and dalteparin was not different in patients treated or not treated with anticancer agents. No effect on recurrent VTE, major bleeding or death was observed with inhibitors or inducers of P-glycoprotein and/or CYP3A4.

CONCLUSION

In our study, concomitant administration of anticancer agents had no effect on the risk of VTE recurrence or major bleeding in patients treated with apixaban or dalteparin for cancer-associated VTE.