Increased bleeding risk associated with concurrent vascular endothelial growth factor receptor tyrosine kinase inhibitors and low-molecular-weight heparin

Bleeding Risk in Patients with Cancer

The hemostatic system and cancer display a tight interconnection, and hemostatic imbalance frequently occurs in patients with cancer. While extensive knowledge about thrombotic risk has been generated, less is known about bleeding risk and associated risk factors. However, bleeding risk is of high significance as patients with cancer frequently receive therapeutic anticoagulation for various indications and/or are candidates for primary thromboprophylaxis. The risk of bleeding in patients with cancer is variable and difficult to assess in clinical practice. Certain clinical settings such as hospitalization, specific underlying risk factors (e.g., tumor type), and medications (e.g., anticoagulation) can contribute to the individual bleeding risk of a patient with cancer. In addition, some dynamic factors such as platelet count or kidney function have an impact. Particularly, data on baseline risk of bleeding are lacking to allow for risk assessment in cancer patients without anticoagulation. In contrast, risk assessment models for the prediction of bleeding events in cancer patients receiving anticoagulation have been developed; however, these have yet to be validated. The recognition of the importance of bleeding risk in cancer patients is growing, leading to an increasing number of studies investigating and reporting bleeding complications. As study designs and reporting of bleeding events vary, it is challenging to offer a clear synthesis of evidence. In this narrative review, we provide an overview of currently available data about incidence, risk factors, and clinical impact of bleeding events in patients with cancer, and critically review risk assessment models for bleeding in cancer patients during anticoagulant therapy.

Portal vein thrombosis: diagnosis, management, and endpoints for future clinical studies

Portal vein thrombosis (PVT) refers to the development of a non-malignant obstruction of the portal vein, its branches, its radicles, or a combination. This Review first provides a comprehensive overview of all aspects of PVT, namely the specifics of the portal venous system, the risk factors for PVT, the pathophysiology of portal hypertension in PVT, the interest in non-invasive tests, as well as therapeutic approaches including the effect of treating risk factors for PVT or cause of cirrhosis, anticoagulation, portal vein recanalisation by interventional radiology, and prevention and management of variceal bleeding in patients with PVT. Specific issues are also addressed including portal cholangiopathy, mesenteric ischaemia and intestinal necrosis, quality of life, fertility, contraception and pregnancy, and PVT in children. This Review will then present endpoints for future clinical studies in PVT, both in patients with and without cirrhosis, agreed by a large panel of experts through a Delphi consensus process. These endpoints include classification of portal vein thrombus extension, classification of PVT evolution, timing of assessment of PVT, and global endpoints for studies on PVT including clinical outcomes. These endpoints will help homogenise studies on PVT and thus facilitate reporting, comparison between studies, and validation of future studies and trials on PVT.

Anti-coagulant Treatment of Cancer-Associated Thrombosis in Frail Patients: Impact of Frailties on the Management of Drug-Drug Interactions

Low molecular weight heparins (LMWH) and anti-Xa direct oral anti-coagulants (DOACs) are recommended for the long-term treatment of cancer-associated thrombosis (CAT) based on well-documented randomised controlled trials. Anti-Xa DOACs are viewed as a first choice for the treatment of patients with CAT. A large number of drug-drug interactions have been reported between DOACs and chemotherapy drugs, modifying circulating levels of DOAC leading to fears of increased bleeding risks or thrombotic recurrence. Progresses in anti-neoplastic therapies have improved the prognosis and the survival, thus increasing the prevalence of frail patients with cancer. However, since frailties tend to be excluded from large trials due to multiple co-morbidities, current guidelines are not fully applicable to this population. The management of these frail patients with CAT is particularly complex and requires a risk assessment on a case-by-case basis with specific focus on cancer, patient-related risk factors and drug-drug interactions. In this brief review we have identified age, co-morbidities and co-medications as key factors of frailty that require careful attention and we have developed a therapeutic decision algorithm to help clinicians optimising the use of anti-coagulants in patients with cancer with CAT, especially in case of anti-Xa DOACs concomitant medications. With the evaluation of the bleeding risk according to the type of cancer, and anticipating drug-drug interactions intensity, taking into account patient frailties allows the optimisation of the anti-coagulant choice. A systematic collaboration between oncologists, vascular pathology specialists and pharmacists is warranted to ensure an optimal patient management. Clinical studies are needed to determine the real impact of these interactions.

The prevalence of relevant drug-drug interactions and associated clinical outcomes in patients with cancer-associated thrombosis on concurrent anticoagulation and anticancer or supportive care therapies

BACKGROUND

A main concern in the management of patients with cancer-associated thrombosis (CAT) is drug-drug interactions (DDIs) between anticoagulants and anticancer therapies. Their clinical implications remain unclear.

METHODS

To quantify the prevalence of DDIs and risks of recurrent venous thromboembolism (VTE) and bleeding events in patients with CAT on anticoagulation, we conducted a retrospective cohort study in patients with CAT on concurrent anticoagulants and anticancer and/or supportive care therapies. All patients were followed for 6 months from CAT diagnosis or until death (whichever occurred first). The primary outcome was the percentage of patients with anticoagulant DDIs classified as risk C, D, or X in Lexicomp® at any time during the 6 months. Secondary outcomes included recurrent VTE and clinically relevant bleeding events. We calculated the 6-month cumulative incidence of outcomes with 95 % confidence interval (CI) and compared those with and without DDIs, considering death as a competing risk.

RESULTS

Among 267 patients included, 111 (41.6 %) had DDIs with anticoagulants at any time during the study. Those on DOACs at any time had more DDIs compared to LMWH (50.9 % vs 19.3 %, p < 0.0001). The 6-month incidence was 8.2 % (95 % CI 5.3-11.9) for recurrent VTE and 6.7 % (95 % CI 4.2-10.2) for clinically relevant bleeding, with no significant differences between groups with or without DDIs.

CONCLUSIONS

There are high incidences of DDIs in patients with CAT on anticoagulants, more with DOACs. DDIs classified as risk C, D, or X by Lexicomp® were not associated with recurrent VTE or bleeding events in our cohort.

Treatment of cancer-associated venous thromboembolism: A focus on special populations

Current evidence-based clinical practice guidelines recommend the use of both low-molecular-weight heparin (LMWH) and direct factor Xa inhibitors (apixapan, edoxaban and rivaroxaban) as first-line options for the treatment of venous thromboembolism (VTE) in patients with cancer. However, most of these guidelines refer to the general cancer patient population and provide limited guidance for specific subgroups of patients at particularly high risk of bleeding, such as those with gastrointestinal cancers, primary or metastatic brain tumors, thrombocytopenia, or renal impairment. In these complex populations, the management of cancer-associated thrombosis (CAT) poses unique challenges and requires a nuanced approach based on the primum non nocere principle. This comprehensive review critically examines the relevant literature and discusses the therapeutic options currently available for the management of CAT in these special situations.

Safety of direct oral anticoagulants in patients with advanced solid tumors receiving anti-VEGF agents: a retrospective study

PURPOSE

Kinase inhibitors (KI) and antibodies targeting the VEGF pathway are approved in a broad spectrum of cancers and associated with an increased risk of bleeding and thromboembolic events (TE). The use of direct oral anticoagulants (DOACs) apixaban and rivaroxaban is increasing in cancer patients, but limited data are available for patients receiving anti-VEGF agents.

METHODS

To assess safety of DOAC with concomitant anti-VEGF agents, a retrospective chart review of all patients receiving concomitantly DOAC and anti-VEGF agents was performed from 2013 to 2020 in our center. Data on demographics, safety, and time on treatment were collected. Main outcome was safety (bleeding and thromboembolic events).

RESULTS

Of 92 patients (median age 66 years (IQR: 59-72)), 40 were treated with KI and 52 with bevacizumab. The most frequent primary tumor sites were colon/rectum (24%), kidney (21%), ovary (13%), lung (11%), soft tissue sarcoma (10%), and thyroid (9%); 2% had brain metastases. Apixaban 5 mg bid (n = 41) or rivaroxaban 20 mg daily (n = 51) were given for TE (65%), atrial fibrillation (32%), or other indications (3%). The median duration of concomitant treatment was 4.8 months (95%CI: 0.7-50.0) with bevacizumab and 11.7 months (95%CI: 0.1-53.8) with KI. Grade ≥ 3 bleeding events occurred in 5 patients (5%): 4 patients receiving bevacizumab (one grade 5 upper digestive tract bleeding and three grade 3 rectal or vaginal hemorrhages) and 1 patient under cabozantinib for kidney cancer with endobronchial metastasis (grade 3 hemoptysis). Grade ≥ 3 TE occurred in 8 patients (9%): 7 patients receiving bevacizumab (including one grade 5 pulmonary embolism), and one patient receiving sunitinib (grade 3 pulmonary embolism). Median time-to-event (bleeding or thrombotic event) was not reached (NR) (95%CI: 76.9-NR) for KI and 86.9 months (95%CI: 42.9-148.0) for bevacizumab. CONCLUSIONS AND RELEVANCE: In our experience, the use of DOAC was safe in selected patients treated with KI, but unclear with bevacizumab. More data are needed to endorse guidelines in this specific group of patients.

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.

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.

Treatment Algorithm in Cancer-Associated Thrombosis: Updated Canadian Expert Consensus

Patients with cancer-associated thrombosis (CAT) are at high risk of recurrent venous thromboembolism (VTE) and major bleeding complications. Risks vary significantly between individuals based on cancer status, treatment, and other characteristics. To facilitate the evidence-based management of anticoagulant therapy in this patient population, a committee of 11 Canadian clinical experts updated a consensus-based algorithm for the acute and extended treatment of symptomatic and incidental CAT that was developed in 2018. Following a systematic review of the literature, updates to the algorithm were discussed during an online teleconference, and the algorithm was subsequently refined based on feedback from committee members. Clinicians using this treatment algorithm should consider bleeding risk, type of cancer, and drug-drug interactions, as well as patient and clinician preferences, in tailoring anticoagulation for patients with CAT. Anticoagulant therapy should be adapted as the patient's cancer status and management change over time.

Combination Therapy in Renal Cell Carcinoma: the Best Choice for Every Patient?

PURPOSE OF REVIEW

Therapeutic alternatives to treat metastatic renal cell carcinoma (mRCC) are increasing, and combination therapies, including antiangiogenic agents and tyrosine kinase/mTOR/immune checkpoint inhibitors, are identified as the gold standard driven by the results of recent clinical studies. Nevertheless, the real-world RCC population is very heterogeneous, with categories of patients not represented in the enrolled trial population who may not benefit more from these treatments. The purpose of this expert review is to assess the rationale on which tyrosine kinase alone may still be a viable first-line treatment option for some subgroups of patients with mRCC.

RECENT FINDINGS

The first-line treatment with tyrosine kinase inhibitor monotherapy can still be considered an effective tool for addressing selected mRCCs, as highlighted by the successful outcome in a range of subjects such as favorable-risk patients, the ones suffering from autoimmune diseases, those with pancreatic or lung metastases, or previously undergoing organ transplantation and elderly subjects. Some selected categories of patients may still benefit from monotherapy with TKI, and smart sequential therapies can also be considered instead of a combination strategy. Tyrosine kinase inhibitors can also act as immune modulator agents, boosting the immune response to facilitate and potentiate the therapeutic effectiveness of subsequent immunotherapy.

Retrospective Study of Bleeding Risk with Concomitant Vascular Endothelial Growth Factor Receptor Tyrosine Kinase Inhibitor and Anticoagulation

BACKGROUND

Patients with cancer are at higher risk for venous thromboembolism (VTE) and bleeding, in turn complicating anticoagulant therapy. An added complexity is the toxicity profile of agents used to treat certain cancers, namely the vascular endothelial growth factor receptor tyrosine kinase inhibitors (TKIs), which are associated with both thromboembolism and hemorrhages. The purpose of this study was to evaluate whether patients taking concurrent VEGF TKI and therapeutic anticoagulant were at higher risk for bleeding compared with patients taking VEGF TKI alone.

MATERIALS AND METHODS

This was a single-center, retrospective chart review of patients who underwent treatment with a VEGF TKI with or without anticoagulant. The primary outcome included comparison of major bleeding rates between groups. Secondary outcomes included comparison of composite major and minor bleed rates and assessment of VTE incidence and recurrence among patients treated with a VEGF TKI and VEGF TKI plus anticoagulant, respectively.

RESULTS

A total of 184 and 74 patients were included in the VEGF TKI alone and VEGF TKI + anticoagulant groups, respectively. Major bleeding events occurred in 6 of 184 patients (3.3%) and 6 of 74 patients (8.1%), respectively (p = .095). Composite major and minor bleeding events occurred in 22 of 184 (13.6%) and 17 of 74 (23%), respectively (p = .026). A total of 26 of 258 patients (10.1%) experienced a VTE event while taking a VEGF TKI, and 1 of 26 (3.8%) experienced a recurrent VTE event while taking a VEGF TKI plus anticoagulant.

CONCLUSION

Patients who received concomitant VEGF TKI plus anticoagulant had increased incidence of bleeding, although prospective studies are needed to further explore this association.

IMPLICATIONS FOR PRACTICE

The current study showed that use of concomitant vascular endothelial growth factor receptor tyrosine kinase inhibitor (VEGF TKI) and therapeutic anticoagulation was associated with an increased risk of composite bleeding events, although at comparable rates between patients treated with VEGF TKI plus direct oral anticoagulant (DOAC) versus VEGF TKI plus non-DOAC anticoagulant. This suggests that when anticoagulation is indicated in a patient receiving a VEGF TKI, the novel DOACs may be a safe alternative to historical anticoagulants (warfarin and enoxaparin). These results fill a gap in the literature and will help guide treatment decisions for patients requiring concurrent VEGF TKI and anticoagulation.