Venous thromboembolism in multiple myeloma - choice of prophylaxis, role of direct oral anticoagulants and special considerations

Bleeding risk from anticoagulant thromboprophylaxis in patients with multiple myeloma: a MarketScan analysis

Background

Multiple myeloma (MM) is associated with high risk of venous thromboembolism (VTE). Anticoagulant prophylaxis is frequently recommended but underutilized partly due to the absence of studies assessing bleeding risk.

Objectives

To determine the rate of severe (hospitalized) bleeding from thromboprophylaxis in patients treated for MM and identify clinical risk factors for bleeding in this population.

Methods

Using the MarketScan database, we analyzed 6656 patients treated for MM between 2013 and 2021. Concomitant thromboprophylaxis was defined using prescription claims. Hospitalized bleeding was identified through the Cunningham algorithm. Bleeding rates were compared by thromboprophylaxis status, and Cox regression identified risk factors for bleeding.

Results

Anticoagulant thromboprophylaxis was used in 6.6% (436) patients treated for MM. Patients on thromboprophylaxis had a higher rate of immunomodulatory-based therapy (63.8% vs 46.7%; P < .01) and lower rate of antiplatelet use (2.1% vs 4.7%; P < .01). Bleeding occurred in 1.4% of them during median follow-up of 1.3 years. Rate of severe bleeding was not different between those on prophylaxis (7.8 per 1000 person-years) and those not on prophylaxis (10.1 per 1000 person-years). No association was identified between thromboprophylaxis and bleeding. Factors associated with increased bleeding included age (hazard ratio [HR], 1.38 per 10 years increase in age), comorbidity index (HR, 1.18 per SD increase), history of bleeding (HR, 1.54), hypertension (HR, 1.87), and renal disease (HR, 1.56).

Conclusion

Risk of serious bleeding from thromboprophylaxis in patients treated for MM was low, and concomitant anticoagulant therapy did not result in increased bleeding risk. Clinical risk factors for bleeding included age, comorbidity index, bleeding history, hypertension, and renal disease.

Validation of the IMPEDE VTE score for prediction of venous thromboembolism in Chinese patients with multiple myeloma: A single-center retrospective cohort study

Multiple myeloma (MM) significantly increases the risk of venous thromboembolism (VTE) within 6 months of treatment initiation. The IMPEDE VTE score is a VTE risk prediction model which is recently incorporated into the National Comprehensive Cancer Network (NCCN) guidelines, but it lacks validation among Asians, including Chinese MM patients. We performed a retrospective chart review of 405 Chinese with newly diagnosed MM who started therapy at Beijing Jishuitan Hospital between April 2013 to October 2022. The 6-month cumulative incidence of VTE was 3.8 % (95 % CI:1.6-7.6), 8.6 % (95 % CI: 5.3-21.9) and 40.5 % (95 % CI: 24.9-55.7) in the low-, intermediate- and high-risk groups (P < 0.001), respectively. The C-statistic of the IMPEDE VTE scores for predicting VTE within 6 months of treatment initiation was 0.74 (95 % CI: 0.65-0.83). Of note, in this single-center cohort study, we propose that the anticoagulant LMWH may be more effective than the antiplatelet aspirin in potentially preventing VTE in newly diagnosed MM patients. Our findings suggest that the IMPEDE VTE score is a valid evidence-based risk stratification tool in Chinese patients with newly diagnosed MM.

Hematologists' awareness of venous thromboembolism in multiple myeloma: a national survey in China

BACKGROUND

Venous thromboembolism (VTE) is one of the most common and severe complications of multiple myeloma (MM). The aim of this study was to learn about the current awareness regarding MM-associated VTE among Chinese hematologists.

METHODS

A nationwide, online, questionnaire-based survey was sent to the specialized hematologists in mainland China. The questionnaire investigated respondents' demographic and occupational characteristics, their ability to identify VTE risk factors, and their thromboprophylaxis decisions for different anti-MM regimens. Six clinical vignettes were used to evaluate hematologists' awareness of stratified thromboprophylaxis. The data were analyzed using SPSS software.

RESULTS

A total of 518 valid questionnaires were received. Of the 518 hematologists investigated, only 23.7% of them could identify VTE-related risk factors correctly. Most hematologists could select appropriate thromboprophylaxis for common anti-MM regimens such as VCd (bortezomib, cyclophosphamide, and dexamethasone) and VRd (bortezomib, lenalidomide, and dexamethasone), but not for uncommon ones such as VTD-PACE (bortezomib, thalidomide, dexamethasone, cisplatin, doxorubicin, cyclophosphamide, and etoposide) and KRd (carfilzomib, lenalidomide, and dexamethasone). The results from the vignettes suggested that only 19.5% of the hematologists could be defined as the 'stratified thromboprophylaxis' group, and the awareness of stratified thromboprophylaxis depended significantly on physicians' age and working seniority.

CONCLUSION

The results of our study showed that a large proportion of Chinese hematologists failed to recognize the VTE risk factors, most of them cannot select appropriate thromboprophylaxis for different MM therapeutic regimens and lack awareness of stratified thromboprophylaxis for MM-associated VTE. A standard VTE prevention guideline is urgently needed for the Chinese myeloma group. Continuous education for new professionals should be encouraged. A VTE collaborative group is supposed to be established in each hospital to enhance the overall medical care for VTE patients.

Thrombosis events in Chinese patients with newly diagnosed multiple myeloma

A high risk of thrombosis is seen in patients with newly diagnosed multiple myeloma (NDMM), particularly those treated with immunomodulatory drugs (IMiDs). Large cohorts addressing the thrombosis issue of NDMM patients in Asia are lacking. We retrospectively analyzed the clinical information of NDMM patients diagnosed in Zhongshan Hospital Fudan University, a national medical center, from January 2013 to June 2021. Death and thrombotic events (TEs) were the endpoints. To investigate risk factors for TEs, the Fine and Gray competing risk regression models were created, in which unrelated deaths were labeled as competing risk events. A total of 931 NDMM patients were recruited in our study. The median follow-up was 23 months [interquartile range (IQR): 9-43 months]. Forty-two patients (4.51%) developed TEs, including 40 cases (4.30%) of venous thrombosis and 2 cases (0.21%) of arterial thrombosis. The median time from taking first-line treatment to TEs occurrence was 2.03 months (IQR: 0.52-5.70 months). The cumulative incidence of TEs was higher in patients treated with IMiDs than in those without IMiDs (8.25 vs. 4.32%, p = 0.038). There was no difference in the incidence of TEs between lenalidomide-based and thalidomide-based groups (7.80 vs. 8.84%, p = 0.886). Besides, TEs occurrence did not adversely affect OS (p = 0.150) or PFS (p = 0.210) in MM patients. Chinese NDMM patients have a lower incidence of thrombosis than those in western countries. The risk of thrombosis was particularly increased in patients treated with IMiDs. TEs were not associated with inferior progression-free survival or overall survival.

Venous thromboembolism in multiple myeloma: Increasing evidence in support of direct oral anticoagulants

Venous thromboembolism (VTE) continues to cause significant morbidity and excess mortality in patients with multiple myeloma. The report by Costa and colleagues demonstrates superiority of direct oral anticoagulants over aspirin in terms of VTE prevention, without increased bleeding complications seen. Commentary on: Costa et al. Direct oral anticoagulants versus aspirin for primary thromboprophylaxis in patients with multiple myeloma undergoing outpatient therapy: A systematic review and updated meta-analysis. Br J Haematol 2023;203:395-403.

Nursing management of treatment-related venous thromboembolism in patients with multiple myeloma

Objectives

Venous thromboembolism (VTE) is a common complication among patients with newly diagnosed multiple myeloma (NDMM). Therefore, this study aimed to analyze the incidence and risk factors associated with VTE in the current era of thromboprophylaxis and to propose appropriate nursing measures.

Methods

A total of 1,539 NDMM patients were retrospectively analyzed. All patients underwent VTE risk assessment and received aspirin or low molecular weight heparin (LMWH) to prevent thrombosis, followed by appropriate care based on their individual thrombosis risk. The incidence of VTE and its related risk factors were then analyzed.

Results

All patients received at least four cycles of therapy containing immunomodulators (IMiDs) and/or proteasome inhibitors (PIs). We assigned 371 patients (24.1%) to the moderate-risk thrombosis group, who received daily aspirin (75 mg) for thrombosis prevention and 1,168 patients (75.9%) to the high-risk group, who received daily low molecular weight heparin (3,000 IU) for thrombosis prevention two times a day. Among all the patients, 53 (3.4%) experienced lower extremity venous thromboembolism events, with three of those patients experiencing a concurrent pulmonary embolism. A multivariate analysis indicated that bed rest lasting more than 2 months and plasma cells of ≥60% were independent factors associated with thrombosis.

Conclusion

More effective risk assessment models are needed to predict thrombosis accurately. In addition, nurses involved in the treatment and management of thrombosis should continually engage in professional development to enhance their knowledge and skills.

Direct oral anticoagulants in patients with venous thromboembolism and hematological malignancies

Data are needed on direct oral anticoagulants (DOACs) for the treatment of venous thromboembolism (VTE) in hematological malignancies (HM). Retrospective studies to date lacked a control group and did not focus on patients with VTE. Out aim was to assess the incidence of VTE recurrence and bleeding in HM patients treated with low molecular weight heparin (LMWH) or DOACs for acute VTE. This is a retrospective cohort study including patients with active HM and newly-diagnosed VTE, indexed on the first day of anticoagulation and followed for 12 months. The outcome was a composite of recurrent VTE, major bleeding or clinically relevant non-major bleeding. Cumulative incidence [95% confidence interval (CI)] was calculated for each anticoagulation group (LMWH, DOAC) and hazard ratios (HR) were calculated using cox-proportional hazards model, with death as a competing risk. 143 HM patients treated with LMWH (96) or DOACs (47) for acute VTE were included. The most common HM types were lymphoma in 83 (58%) and plasma cell dyscrasia in 32 (22.3%). The 12-month cumulative incidence of the composite outcome was 24.2% (95% CI 15.9-33.5%; n = 22) in the LMWH group and 18.5% (8.5-31.5%; n = 8) in the DOAC group (HR 1.51 [0.695-3.297]). Two recurrent VTE occurred (both in the DOAC group while off-treatment). Nine (9.4%) LMWH-treated patients had major bleeding compared to 1 (2.1%) DOAC-treated patient (HR 4.85 [0.64-36.56]). This study generates the hypothesis that DOACs may be a safe and effective alternative to LMWH for VTE in patients with HM types represented in the study.

Cardiovascular Toxicity of Proteasome Inhibitors in Multiple Myeloma Therapy

The treatment for multiple myeloma has advanced significantly over the past few decades. Proteasome inhibitors have become the cornerstone of the treatment of multiple myeloma. However, proteasome inhibitors have shown cardiovascular complications such as hypertension, pulmonary hypertension, heart failure, arrhythmias, ischaemic heart disease and thromboembolism. Detection, monitoring and management of proteasome inhibitor-related cardiovascular toxicity are essential to improve clinical outcomes for patients. Proposed mechanisms of proteasome inhibitor-related cardiovascular toxicity are apoptosis, prolonged inhibition of the ubiquitin-proteasome system, accumulation of improperly folded proteins within cardiomyocytes and higher protein phosphatase 2A activity. To better understand the mechanisms underlying cardiotoxicity, further in vitro and in vivo experiments are required to investigate these hypotheses. Combined use of metformin or angiotensin II receptor blockers with the proteasome inhibitor, carfilzomib, showed an emerging role as a prophylactic therapy because they can preserve heart function in multiple myeloma patients. Metformin is expected to be an effective therapeutic intervention for the management of carfilzomib-induced cardiotoxicity. There has been evidence that three compounds, apremilast, rutin, and dexrazoxane, can reverse carfilzomib-induced cardiotoxicity in rats. The future transition from animal experiments to clinical trials is worth waiting for.

Approach to Contemporary Risk Assessment, Prevention and Management of Thrombotic Complications in Multiple Myeloma

Multiple myeloma (MM) is associated with an increased risk of thrombotic complications, which remains substantial despite the implementation of thromboprophylaxis. The procoagulant state that characterizes the disease is multifactorial, and a greater understanding of the underlying pathophysiology is required to inform appropriate thrombosis prevention. Currently, there is a shift towards using direct oral anticoagulants (DOACs) in this setting; head-to-head comparisons in the context of controlled clinical trials between class agents are still missing. MM-specific VTE risk assessment scores have been developed to optimize management and minimize the associated mortality/morbidity. Their clinical utility remains to be evaluated. The value of adding biomarkers to clinical scores to optimize their performance and increase their discriminatory power is also under assessment.

Causal relationship between 14 site-specific cancers and venous thromboembolism

BACKGROUND

It has been observed that cancer and venous thromboembolism (VTE) are associated, but anticancer therapy may violate the causality. Therefore, this study aimed to elucidate the causal relationship of various cancers to VTE using Mendelian randomization (MR).

METHODS

Three MR methods were used to estimate causal effects: Inverse variance weighted (IVW), MR-Egger and weighted median. Sensitivity analyses included Cochran's Q-test, MR-Egger intercept test and MR-PRESSO. Gene ontology enrichment analysis was performed to elucidate the underlying mechanisms of VTE development in cancer patients.

RESULTS

The primary IVW approach showed that non-Hodgkin's lymphoma (NHL) might increase the risk of VTE (odds ratio [OR]: 1.20, 95% confidence interval [95% CI]: 1.00-1.44, p = 0.045), while melanoma possibly reduced the risk of VTE (OR: 0.89, 95% CI: 0.82-0.97, p = 0.006), although there was no significance after adjustment for multiple testing. No association was observed between VTE risk and other site-specific cancers. Gene ontology enrichment analysis revealed that vitamin D played an important role in the development of VTE in cancer patients.

CONCLUSIONS

Our findings suggested that genetically predicted NHL was associated with higher VTE risk, whereas melanoma had lower VTE risk compared with other site-specific cancers. Moreover, this study suggested that anticancer therapy and increased extensive examination might play a more important role in VTE development than the nature of cancer.

Roadmap for new practitioners to navigate the multiple myeloma landscape

Multiple myeloma (MM) is a blood cancer in which monoclonal plasma cells cause end organ damage resulting in hypercalcemia, renal failure, anemia, and bone lesions. MM is considered incurable, however, recent advances in treatment have improved survival. Historically, MM has been treated with immunomodulatory drugs (IMiDs), proteosome inhibitors (PIs), and corticosteroids. While newer therapeutic approaches such as monoclonal antibodies and cellular therapies have broadened the treatment horizon, the selection and sequencing of these therapies has become more complex. This review aims to help advanced practice providers navigate through the diagnosis, staging, treatment, and supportive care considerations in the MM space.

Prediction of venous thromboembolism in patients with multiple myeloma treated with lenalidomide, bortezomib, dexamethasone, and transplantation: Lessons from the substudy of IFM/DFCI 2009 cohort

BACKGROUND

Venous thromboembolism (VTE) is a concern for patients with newly diagnosed multiple myeloma.

OBJECTIVES

We aimed to evaluate VTE incidence, risk factors, and risk score.

PATIENTS/METHODS

We performed a substudy of the "Intergroupe Francophone du Myelome 2009" randomized controlled trial.

RESULTS

We assessed 700 patients receiving lenalidomide/bortezomib/dexamethasone, followed or not by autologous hematopoietic stem cell transplantation. VTE incidence at 6 months was 4.8% (95% confidence interval [CI]: 3.3-6.9%) and 1.5% (95% CI: 0.8-2.9%) from 6 to 12 months. Using multivariate analysis we confirmed history of VTE (odds ratio 5.1 [1.6-16.7], P = .007) as a strong VTE-related risk factor, invalidated erythropoietin exposure (0.6 [0.2-1.7], P = .3) as risk factor, and added two new risk factors: fracture at diagnosis (2.6 [1.3-5.5], P = .01), and serum gamma globulin level > 27 g/L (2.8 [1.2-6.8,] P = .02). Moreover, we noticed that VTE occurred earlier in patients with gamma globulin levels >27 g/L, suggesting a need to revisit the thromboprophylaxis timeframe. Heparin administration was associated with a decreased risk (0.3 [0.1-0.7], P = .005) but failed to erase the risk regardless of dose. The area under the receiver operating characteristic curve of the IMPEDE VTE score was 0.67, as previously reported, confirming our cohort was well representative.

CONCLUSIONS

Prospective studies are warranted in light of these results to improve VTE risk stratification and to design adapted thromboprophylaxis in terms of timing and dose.

The role of VWF/FVIII in thrombosis and cancer progression in multiple myeloma and other hematological malignancies

Cancer associated thrombosis (CAT) is associated with significant morbidity and mortality, highlighting an unmet clinical need to improve understanding of the pathophysiology of CAT. Multiple myeloma (MM) is associated with one of the highest rates of thrombosis despite widespread use of thromboprophylactic agents. The pathophysiology of thrombosis in MM is multifactorial and patients with MM appear to display a hypercoagulable phenotype with potential contributory factors including raised von Willebrand factor (VWF) levels, activated protein C resistance, impaired fibrinolysis, and abnormal thrombin generation. In addition, the toxic effect of anti-myeloma therapies on the endothelium and contribution to thrombosis has been widely described. Elevated VWF/factor VIII (FVIII) plasma levels have been reported in heterogeneous cohorts of patients with MM and other hematological malignancies. In specific studies, high plasma VWF levels have been shown to associate with VTE risk and reduced overall survival. While the mechanisms underpinning this remain unclear, dysregulation of the VWF and A Disintegrin And Metalloprotease Thrombospondin type 1, motif 13 (ADAMTS-13) axis is evident in certain solid organ malignancies and correlates with advanced disease and thrombosis. Furthermore, thrombotic microangiopathic conditions arising from deficiencies in ADAMTS-13 and thus an accumulation of prothrombotic VWF multimers have been reported in patients with MM, particularly in association with specific myeloma therapies. This review will discuss current evidence on the pathophysiological mechanisms underpinning thrombosis in MM and in particular summarize the role of VWF/FVIII in hematological malignancies with a focus on thrombotic risk and emerging evidence for contribution to disease progression.

Peripheral Neuropathy During Concomitant Administration of Proteasome Inhibitors and Factor Xa Inhibitors: Identifying the Likelihood of Drug-Drug Interactions

Backgrounds: Proteasome inhibitors (PI) cause toxic peripheral neuropathy (PN), which is one of the dose-limiting adverse events of these treatments. Recent preclinical studies find that factor Xa inhibitor (FXaI), rivaroxaban, promotes PN in animals receiving oxaliplatin. Cancer patients can receive combined therapy of PI and FXaI. This study aimed to identify and characterize the interaction signals for the concomitant use of PI and FXaI resulting in PN.

Methods: Reports from the United States FDA Adverse Event Reporting System (FAERS) were extracted from the first quarter of 2004 to the first quarter of 2020 for analysis. The Standardized Medical Dictionary for Regulatory Activities (MedDRA) query was used to identify PN cases. We conducted an initial disproportionality investigation to detect PN adverse event signals associated with the combined use of PI and FXaI by estimating a reporting odds ratio (ROR) with a 95% confidence interval (CI). The adjusted RORs were then analyzed by logistic regression analysis (adjusting for age, gender, and reporting year), and additive/multiplicative models were performed to further confirm the findings. Additionally, subset data analysis was performed on the basis of a single drug of PI and FXaI.

Results: A total of 159,317 adverse event reports (including 2,822 PN reports) were included. The combined use of PI and FXaI was associated with a higher reporting of PN (RORadj = 7.890, 95%CI, 5.321–11.698). The result remained significant based on additive/multiplicative methods. The observed association was consistent in the analysis restricted to all specific PI agents (bortezomib and ixazomib) and FXaI (rivaroxaban), except apixaban.

Conclusion: Analysis of FAERS data identified reporting associations of PN in the combined use of PI and FXaI, suggesting the need for more robust preclinical and clinical studies to elucidate the relationship.

Cardio-Oncology Drug Interactions: A Scientific Statement From the American Heart Association

In the cardio-oncology population, drug interactions are of particular importance given the complex pharmacological profile, narrow therapeutic index, and inherent risk of therapies used to manage cardiovascular disease and cancer. Drug interactions may be beneficial or detrimental to the desired therapeutic effect. Clinicians in both cardiology and oncology should be cognizant of these potential drug-drug interactions that may reduce the efficacy or safety of either cardiovascular or cancer therapies. These risks can be mitigated through increased recognition of potential drug-drug interaction, use of alternative medications when possible, and careful monitoring. This scientific statement provides clinicians with an overview of pharmacodynamic and pharmacokinetic drug-drug interactions in patients with cancer exposed to common cardiovascular and cancer medications.

Recurrent hematuria and painful necrotic purpura induced by acquired Protein S deficiency associated with monoclonal immunoglobulin

Protein S deficiency is associated with an increased risk of thromboembolism, which may be caused by hereditary deficiency and several physiological and pathologic conditions, such as pregnancy, contraceptive use, liver diseases, inflammatory disease, and certain viruses infections. However, monoclonal immunoglobulin-mediated Protein S deficiency is rarely reported. Here we described a 49-year-old woman with a history of recurrent painful swelling in both lower extremities due to venous thrombosis for 7 years, accompanied by recurrent gross hematuria and multiple painful necrotic purpuras for 5 years, who was then diagnosed with acquired Protein S deficiency induced by the monoclonal immunoglobulin. Then she was successfully treated with rituximab combined with anticoagulation therapy. This case highlights the rare manifestations of Protein S deficiency and the influence of the monoclonal immunoglobulin produced by monoclonal B lymphocytes and monoclonal plasma cells on the activity of Protein S, which can be treated effectively with rituximab combined with anticoagulation therapy.

Optimising cardiovascular care of patients with multiple myeloma

Multiple myeloma (MM) is the third most common haematological malignancy, with increasing prevalence over recent years. Advances in therapy have improved survival, changing the clinical course of MM into a chronic condition and meaning that management of comorbidities is fundamental to improve clinical outcomes. Cardiovascular (CV) events affect up to 7.5% of individuals with MM, due to a combination of patient, disease and treatment-related factors and adversely impact survival. MM typically affects older people, many with pre-existing CV risk factors or established CV disease, and the disease itself can cause renal impairment, anaemia and hyperviscosity, which exacerabate these further. Up to 15% of patients with MM develop systemic amyloidosis, with prognosis determined by the extent of cardiac involvement. Management of MM generally involves administration of multiple treatment lines over several years as disease progresses, with many drug classes associated with adverse CV effects including high rates of venous and arterial thrombosis alongside heart failure. Recommendations for holistic management of patients with MM now include routine baseline risk stratification including ECG and echocardiography and administration of thromboprophylaxis drugs for patients treated with immunomodulatory drugs. Close surveillance of high-risk patients with collaboration between haematology and cardiology is required, with prompt investigation in the event of CV symptoms, in order to identify and treat complications early. Decisions regarding discontinuation of cardiotoxic therapies should be made in a multidisciplinary setting, taking into account the severity of the complication, prognosis, expected benefits and the availability of effective alternatives.

Antithrombotic therapy for ambulatory patients with multiple myeloma receiving immunomodulatory agents

BACKGROUND

Multiple myeloma is a malignant plasma cell disorder characterised by clonal plasma cells that cause end-organ damage such as renal failure, lytic bone lesions, hypercalcaemia and/or anaemia. People with multiple myeloma are treated with immunomodulatory agents including lenalidomide, pomalidomide, and thalidomide. Multiple myeloma is associated with an increased risk of thromboembolism, which appears to be further increased in people receiving immunomodulatory agents.

OBJECTIVES

(1) To systematically review the evidence for the relative efficacy and safety of aspirin, oral anticoagulants, or parenteral anticoagulants in ambulatory patients with multiple myeloma receiving immunomodulatory agents who otherwise have no standard therapeutic or prophylactic indication for anticoagulation. (2) To maintain this review as a living systematic review by continually running the searches and incorporating newly identified studies.

SEARCH METHODS

We conducted a comprehensive literature search that included (1) a major electronic search (14 June 2021) of the following databases: Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE via Ovid, and Embase via Ovid; (2) hand-searching of conference proceedings; (3) checking of reference lists of included studies; and (4) a search for ongoing studies in trial registries. As part of the living systematic review approach, we are running continual searches, and we will incorporate new evidence rapidly after it is identified.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing the benefits and harms of oral anticoagulants such as vitamin K antagonist (VKA) and direct oral anticoagulants (DOAC), anti-platelet agents such as aspirin (ASA), and parenteral anticoagulants such as low molecular weight heparin (LMWH)in ambulatory patients with multiple myeloma receiving immunomodulatory agents.

DATA COLLECTION AND ANALYSIS

Using a standardised form, we extracted data in duplicate on study design, participants, interventions, outcomes of interest, and risk of bias. Outcomes of interest included all-cause mortality, symptomatic deep vein thrombosis (DVT), pulmonary embolism (PE), major bleeding, and minor bleeding. For each outcome we calculated the risk ratio (RR) with its 95% confidence interval (CI) and the risk difference (RD) with its 95% CI. We then assessed the certainty of evidence at the outcome level following the GRADE approach (GRADE Handbook).

MAIN RESULTS

We identified 1015 identified citations and included 11 articles reporting four RCTs that enrolled 1042 participants. The included studies made the following comparisons: ASA versus VKA (one study); ASA versus LMWH (two studies); VKA versus LMWH (one study); and ASA versus DOAC (two studies, one of which was an abstract). ASA versus VKA One RCT compared ASA to VKA at six months follow-up. The data did not confirm or exclude a beneficial or detrimental effect of ASA relative to VKA on all-cause mortality (RR 3.00, 95% CI 0.12 to 73.24; RD 2 more per 1000, 95% CI 1 fewer to 72 more; very low-certainty evidence); symptomatic DVT (RR 0.57, 95% CI 0.24 to 1.33; RD 27 fewer per 1000, 95% CI 48 fewer to 21 more; very low-certainty evidence); PE (RR 1.00, 95% CI 0.25 to 3.95; RD 0 fewer per 1000, 95% CI 14 fewer to 54 more; very low-certainty evidence); major bleeding (RR 7.00, 95% CI 0.36 to 134.72; RD 6 more per 1000, 95% CI 1 fewer to 134 more; very low-certainty evidence); and minor bleeding (RR 6.00, 95% CI 0.73 to 49.43; RD 23 more per 1000, 95% CI 1 fewer to 220 more; very low-certainty evidence). One RCT compared ASA to VKA at two years follow-up. The data did not confirm or exclude a beneficial or detrimental effect of ASA relative to VKA on all-cause mortality (RR 0.50, 95% CI 0.05 to 5.47; RD 5 fewer per 1000, 95% CI 9 fewer to 41 more; very low-certainty evidence); symptomatic DVT (RR 0.71, 95% CI 0.35 to 1.44; RD 22 fewer per 1000, 95% CI 50 fewer to 34 more; very low-certainty evidence); and PE (RR 1.00, 95% CI 0.25 to 3.95; RD 0 fewer per 1000, 95% CI 14 fewer to 54 more; very low-certainty evidence). ASA versus LMWH Two RCTs compared ASA to LMWH at six months follow-up. The pooled data did not confirm or exclude a beneficial or detrimental effect of ASA relative to LMWH on all-cause mortality (RR 1.00, 95% CI 0.06 to 15.81; RD 0 fewer per 1000, 95% CI 2 fewer to 38 more; very low-certainty evidence); symptomatic DVT (RR 1.23, 95% CI 0.49 to 3.08; RD 5 more per 1000, 95% CI 11 fewer to 43 more; very low-certainty evidence); PE (RR 7.71, 95% CI 0.97 to 61.44; RD 7 more per 1000, 95% CI 0 fewer to 60 more; very low-certainty evidence); major bleeding (RR 6.97, 95% CI 0.36 to 134.11; RD 6 more per 1000, 95% CI 1 fewer to 133 more; very low-certainty evidence); and minor bleeding (RR 1.42, 95% CI 0.35 to 5.78; RD 4 more per 1000, 95% CI 7 fewer to 50 more; very low-certainty evidence). One RCT compared ASA to LMWH at two years follow-up. The pooled data did not confirm or exclude a beneficial or detrimental effect of ASA relative to LMWH on all-cause mortality (RR 1.00, 95% CI 0.06 to 15.89; RD 0 fewer per 1000, 95% CI 4 fewer to 68 more; very low-certainty evidence); symptomatic DVT (RR 1.20, 95% CI 0.53 to 2.72; RD 9 more per 1000, 95% CI 21 fewer to 78 more; very low-certainty evidence); and PE (RR 9.00, 95% CI 0.49 to 166.17; RD 8 more per 1000, 95% CI 1 fewer to 165 more; very low-certainty evidence). VKA versus LMWH One RCT compared VKA to LMWH at six months follow-up. The data did not confirm or exclude a beneficial or detrimental effect of VKA relative to LMWH on all-cause mortality (RR 0.33, 95% CI 0.01 to 8.10; RD 3 fewer per 1000, 95% CI 5 fewer to 32 more; very low-certainty evidence); symptomatic DVT (RR 2.32, 95% CI 0.91 to 5.93; RD 36 more per 1000, 95% CI 2 fewer to 135 more; very low-certainty evidence); PE (RR 8.96, 95% CI 0.49 to 165.42; RD 8 more per 1000, 95% CI 1 fewer to 164 more; very low-certainty evidence); and minor bleeding (RR 0.33, 95% CI 0.03 to 3.17; RD 9 fewer per 1000, 95% CI 13 fewer to 30 more; very low-certainty evidence). The study reported that no major bleeding occurred in either arm. One RCT compared VKA to LMWH at two years follow-up. The data did not confirm or exclude a beneficial or detrimental effect of VKA relative to LMWH on all-cause mortality (RR 2.00, 95% CI 0.18 to 21.90; RD 5 more per 1000, 95% CI 4 fewer to 95 more; very low-certainty evidence); symptomatic DVT (RR 1.70, 95% CI 0.80 to 3.63; RD 32 more per 1000, 95% CI 9 fewer to 120 more; very low-certainty evidence); and PE (RR 9.00, 95% CI 0.49 to 166.17; RD 8 more per 1000, 95% CI 1 fewer to 165 more; very low-certainty evidence). ASA versus DOAC One RCT compared ASA to DOAC at six months follow-up. The data did not confirm or exclude a beneficial or detrimental effect of ASA relative to DOAC on DVT, PE, and major bleeding and minor bleeding (minor bleeding: RR 5.00, 95% CI 0.31 to 79.94; RD 4 more per 1000, 95% CI 1 fewer to 79 more; very low-certainty evidence). The study reported that no DVT, PE, or major bleeding events occurred in either arm. These results did not change in a meta-analysis including the study published as an abstract.

AUTHORS' CONCLUSIONS

The certainty of the available evidence for the comparative effects of ASA, VKA, LMWH, and DOAC on all-cause mortality, DVT, PE, or bleeding was either low or very low. People with multiple myeloma considering antithrombotic agents should balance the possible benefits of reduced thromboembolic complications with the possible harms and burden of anticoagulants. Editorial note: This is a living systematic review. Living systematic reviews offer a new approach to review updating in which the review is continually updated, incorporating relevant new evidence as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Viscoelastic testing in oncology patients (including for the diagnosis of fibrinolysis): Review of existing evidence, technology comparison, and clinical utility

The quantification of the coagulopathic state associated with oncologic and hematologic diseases is imperfectly assessed by common coagulation tests such as prothrombin time, activated partial thromboplastin time, fibrinogen levels, and platelet count. These tests provide a static representation of a component of hemostatic integrity, presenting an incomplete picture of coagulation in these patients. Viscoelastic tests (VETs), such as rotational thromboelastometry (ROTEM) and thromboelastography (TEG), as whole blood analyses, provide data related to the cumulative effects of blood components and all stages of the coagulation and fibrinolytic processes. The utility of VETs has been demonstrated since the late 1960s in guiding blood component therapy for patients undergoing liver transplantation. Since then, the scope of viscoelastic testing has expanded to become routinely used for cardiac surgery, obstetrics, and trauma. In the past decade, VETs' expanded usage has been most significant in trauma resuscitation. However, use of VETs for patients with malignancy-associated coagulopathy (MAC) and hematologic malignancies is increasing. For the purposes of this narrative review, we discuss the similarities between trauma-induced coagulopathy (TIC) and MAC. These similarities center on the thrombomodulin-thrombin complex as it switches between the thrombin-activatable fibrinolysis inhibitor coagulation pathway and activating the protein C anticoagulation pathway. This produces a spectrum of coagulopathy and fibrinolytic alterations ranging from shutdown to hyperfibrinolysis that are common to TIC, MAC, and hematologic malignancies. There is expanding literature regarding the utility of TEG and ROTEM to describe the hemostatic integrity of patients with oncologic and hematologic conditions, which we review here.

Initial Therapeutic Approaches to Patients with Multiple Myeloma

Multiple Myeloma (MM) is part of a spectrum of plasma cell disorders that may result in end organ damage. MM is subclassified into high and standard risk based on cytogenetic and laboratory markers. The treatment of newly diagnosed multiple myeloma is constantly changing with the advent of novel therapies. Recent advances in therapies have resulted in longer time to remission and overall survival. the introduction of targeted therapy with monoclonal antibodies such as Daratumumab has improved stringent complete response to 39%. In this review, we outline the current approach to diagnosis, prognosis, and management of newly diagnosed multiple myeloma in both transplant eligible and ineligible patients.

Safety of lenalidomide for maintenance treatment of patients with multiple myeloma following autologous stem cell transplantation

INTRODUCTION

Myeloma is the second most common hematological cancer, with 5800 cases per year diagnosed in the UK. Despite improved treatment it is still considered non-curable, although the median survival has increased from 3 to 8 years over the past 20 years. Treatment involves the use of induction therapy and consolidation with autologous stem cell transplant (ASCT) in patients deemed fit enough. Further attempts to improve outcomes include the use of maintenance therapy.

AREAS COVERED

This review details all trials in which lenalidomide has been used as maintenance following ASCT. PubMed searches included randomized control trials, observational cohort, reviews, and meta-analysis.

EXPERT OPINION

Lenalidomide is a well-tolerated, oral agent that is associated with increased overall and progression free survival when used as maintenance following ASCT. Its use in this setting is FDA and EMA approved and is standard of care in Europe and North America. The early link between lenalidomide and second hematological cancers appears to be associated with use in combination with melphalan. There is an increase in non-melanoma skin cancers and solid tumors in the elderly but this has minimal impact on mortality. Lenalidomide use as part of combination maintenance is underway and may further improve outcomes.

Thromboembolic events and thromboprophylaxis associated with immunomodulators in multiple myeloma patients: a real-life study

PURPOSE

The aim of this study is to assess international guidelines implementation concerning thromboprophylaxis strategy in myeloma patients treated with immunomodulatory drugs.

METHODS

This retrospective study includes multiple myeloma patients treated with immunomodulatory drugs between 2014 and 2017 in the Hematology department of a teaching hospital (Hospices Civils de Lyon, France) and followed by the multidisciplinary care plan for cancer outpatients ONCORAL (ONCological care for outpatients with ORAL anticancer drugs). Data from immunomodulatory drugs administration, thromboprophylaxis strategy and thrombotic events were collected from medical files. Adherence to 2010 International Myeloma Working Group (IMWG) guidelines was assessed.

RESULTS

213 patients received at least one immunomodulatory drug: lenalidomide (60.9%), pomalidomide (24.0%) and thalidomide (15.1%). About two third of treatment lines (66.2%) were in accordance with IMWG recommendations. Among the others, 30.5% and 69.5% had thromboprophylaxis, respectively, superior or inferior to IMWG recommendations. 37 venous thrombotic events and 4 arterial thromboembolisms (one patient experienced both a stroke and deep venous thrombosis simultaneously) were reported.

CONCLUSION

Thromboprophylaxis was systematically performed in myeloma patients treated with immunomodulatory drugs in this real-life retrospective cohort. However, the choice of anticoagulant or anti-platelet agent remains debatable, as adherence to existing guidelines was variable.

Validation of the IMPEDE VTE score for prediction of venous thromboembolism in multiple myeloma: a retrospective cohort study

The IMPEDE VTE score has recently emerged as a novel risk prediction tool for venous thromboembolism (VTE) in multiple myeloma (MM). We retrospectively reviewed 839 patients with newly diagnosed MM between 2010 and 2015 at Cleveland Clinic and included 575 patients in final analysis to validate this score. The c-statistic of the IMPEDE VTE score to predict VTE within 6 months of treatment start was 0·68 (95% CI: 0·61-0·75). The 6-month cumulative incidence of VTE was 5·0% (95% CI: 2·1-7·9) in the low risk group, compared to 12·6% (95% CI: 8·9-16·4%) and 24·1% (95% CI: 12·2-36·1) in the intermediate and high risk groups (P < 0·001 for both). In addition, a higher proportion of patients in the VTE cohort had ECOG performance status of ≥2 as compared to the no VTE cohort (33% vs. 16%, P = 0·001). Other MM characteristics such as stage, immunoglobulin subtype, and cytogenetics were not predictors of VTE. In summary, we have validated the IMPEDE VTE score in our patient cohort and our findings suggest that it can be utilized as a VTE risk stratification tool in prospective studies looking into investigating VTE prophylaxis strategies in MM patients.

Venous thromboembolism prophylaxis in patients with multiple myeloma: where are we and where are we going?

Venous thromboembolism is a common complication of patients with hematologic malignancies, due both to release of procoagulant factors by tumor cells and to external factors, such us drugs. In multiple myeloma patients, the risk is increased by use of immunomodulants, especially when associated to multidrug therapy, during the induction phase. Prevention of venous thromboembolism in myeloma patients is highly recommended but specific guidelines are still lacking. The most common approach is to stratify the thrombotic risk according to individual, myeloma-related and therapy-related risk factors and to use aspirin for all patients, except those with two or more thrombotic risk factors who should be treated with traditional oral or parenteral anticoagulant. A more controversial approach indicates for prophylaxis either anticoagulant or aspirin, regardless of risk stratification. Recent trials investigate prophylaxis in myeloma patients with direct oral anticoagulants, based on studies showing efficacy and safety of this new class of drugs in the treatment and prophylaxis of thrombosis in patients with any malignancy. The results of these trials are encouraging but they need to be confirmed by larger studies. An international consensus about best prophylaxis to prevent venous thromboembolism in patients with multiple myeloma on treatment is still missing. Therefore, thrombosis in multiple myeloma remains an ongoing issue.

Prediction and Prevention of Cancer-Associated Thromboembolism

Venous and arterial thromboembolism are prevalent, highly burdensome, and associated with risk of worse outcomes for patients with cancer. Risk for venous thromboembolism (VTE) varies widely across specific cancer subpopulations. The ability to predict risk of cancer-associated VTE is critical because an optimal thromboprophylaxis strategy is best achieved by targeting high-risk patients with cancer and avoiding prophylaxis in patients with cancer at low risk for VTE. A validated risk tool for solid tumors has been available for a decade. Newer tools have focused on specific populations, such as patients with multiple myeloma. Emerging studies continue to optimize risk prediction approaches in patients with cancer. Recent randomized trials have specifically addressed risk-adapted thromboprophylaxis using direct oral anticoagulants, and revised guidelines have included these new data to formulate recommendations for outpatient thromboprophylaxis. Implementation science approaches to enhance use of outpatient prophylaxis in the context of these guideline changes are under way. However, major knowledge gaps remain, including a lack of data for inpatient thromboprophylaxis in the cancer setting and a lack of formal tools for identifying risk of bleeding. This review describes optimal approaches to risk prediction and patient selection for primary pharmacologic thromboprophylaxis of cancer-associated VTE, addresses barriers to implementing these practices, and highlights strategies to overcome them. IMPLICATIONS FOR PRACTICE: Risk for venous thromboembolism (VTE) varies widely among patients with cancer. Individual risk can be determined using validated approaches. Inpatient and postsurgical thromboprophylaxis is more widely accepted. However, most patients with cancer develop VTE in the outpatient setting. Recent randomized trials have demonstrated benefit to risk-adapted outpatient thromboprophylaxis. High-risk patients may therefore be considered for outpatient thromboprophylaxis as recommended by recently updated guidelines. System-wide implementation approaches are necessary to improve compliance with prophylaxis.

Venous thromboembolism in multiple myeloma is associated with increased mortality

BACKGROUND

In multiple myeloma, venous thromboembolism (VTE) is common, and treatments for myeloma, such as lenalidomide, increase the risk of thrombosis while improving survival. The association between VTE and survival is not well known.

OBJECTIVES

To determine the association between VTE and survival in multiple myeloma (MM) while adjusting for known confounders that affect risk of thrombosis and survival, including patient characteristics and treatment in a retrospective cohort of US veterans.

PATIENTS/METHODS

A cohort of patients with newly diagnosed MM treated within Veterans Health Administration between September 1, 1999, and June 30, 2014, was created to assess the association between VTE and mortality using Cox proportional hazards regression modeling while accounting for known prognostic factors and treatments.

RESULTS

The cohort comprised 4446 patients with myeloma, including 2837 patients diagnosed after lenalidomide approval in July 2006. VTE occurred in 327 (7.4%) patients within 1 year and occurred at a median of 77 days (interquartile range, 37-153) after starting therapy for MM. In all patients, VTE was associated with increased mortality at 6 months (adjusted hazard ratio [aHR], 1.67; 95% confidence interval [CI], 1.18-2.37). Patients in the post-lenalidomide cohort with VTE had an increased mortality at both 6 months (aHR, 2.31; 95% CI, 1.52-3.51) and 12 months (aHR, 1.66; 95% CI, 1.19-2.33) after treatment initiation.

DISCUSSION

This study shows that VTE during the first 6-12 months of therapy is associated with increased mortality in patients with MM. Studies evaluating thromboprophylaxis in patients at high risk of thrombosis are needed.

Thrombosis in patients with myeloma treated in the Myeloma IX and Myeloma XI phase 3 randomized controlled trials

Newly diagnosed multiple myeloma (NDMM) patients treated with immunomodulatory drugs are at high risk of venous thromboembolism (VTE), but data are lacking from large prospective cohorts. We present thrombosis outcome data from Myeloma IX (n = 1936) and Myeloma XI (n = 4358) phase 3 randomized controlled trials for NDMM that treated transplant-eligible and transplant-ineligible patients before and after publication of thrombosis prevention guidelines. In Myeloma IX, transplant-eligible patients randomly assigned to cyclophosphamide, vincristine, doxorubicin, and dexamethasone (CVAD) induction had higher risk of VTE compared with patients treated with cyclophosphamide, thalidomide, and dexamethasone (CTD) (22.5% [n = 121 of 538] vs 16.1% [n = 89 of 554]; adjusted hazard ratio [aHR],1.46; 95% confidence interval [95% CI], 1.11-1.93). For transplant-ineligible patients, those randomly assigned to attenuated CTD (CTDa) induction had a higher risk of VTE compared with those treated with melphalan and prednisolone (MP) (16.0% [n = 68 of 425] vs 4.1% [n = 17 of 419]; aHR, 4.25; 95% CI, 2.50-7.20). In Myeloma XI, there was no difference in risk of VTE (12.2% [n = 124 of 1014] vs 13.2% [n = 133 of 1008]; aHR, 0.92; 95% CI, 0.72-1.18) or arterial thrombosis (1.2% [n = 12 of 1014] vs 1.5% [n = 15 of 1008]; aHR, 0.80; 95% CI, 0.37-1.70) between transplant-eligible pathways for patients treated with cyclophosphamide, lenalidomide, and dexamethasone (CRD) or CTD. For transplant-ineligible patients, there was no difference in VTEs between attenuated CRD (CRDa) and CTDa (10.4% [n = 95 of 916] vs 10.7% [n = 97 of 910]; aHR, 0.97; 95% CI, 0.73-1.29). However, arterial risk was higher with CRDa than with CTDa (3.1% [n = 28 of 916] vs 1.6% [n = 15 of 910]; aHR, 1.91; 95% CI, 1.02-3.57). Thrombotic events occurred almost entirely within 6 months of treatment initiation. Thrombosis was not associated with inferior progression-free survival (PFS) or overall survival (OS), apart from inferior OS for patients with arterial events (aHR, 1.53; 95% CI, 1.12-2.08) in Myeloma XI. The Myeloma XI trial protocol incorporated International Myeloma Working Group (IMWG) thrombosis prevention recommendations and compared with Myeloma IX, more patients received thromboprophylaxis (80.5% vs 22.3%) with lower rates of VTE for identical regimens (CTD, 13.2% vs 16.1%; CTDa, 10.7% vs 16.0%). However, thrombosis remained frequent in spite of IMWG-guided thromboprophylaxis, suggesting that new approaches are needed.

The induction strategies administered in the treatment of multiple myeloma exhibit a deleterious effect on the endothelium

Multiple myeloma induction treatment includes proteasome inhibitors (PI) and immunomodulatory agents at present. The incidence of engraftment syndrome, a transplant complication potentially related to endothelium, has increased in the last years. Our aim was to investigate whether bortezomib (Velcade, V), thalidomide (T), and dexamethasone (D) affect the endothelium, and explore defibrotide (DF) as protective agent. Endothelial cells (ECs) in culture were exposed to the compounds separately or in combination, without (VTD) and with DF (VTD + DF). Changes in markers of: (i) inflammation (ICAM-1 expression and leukocyte adhesion), (ii) VWF production, (iii) cell permeability (VE-cadherin expression and cell monolayer integrity), and (iv) oxidative stress (ROS production and eNOS expression) were measured. ICAM-1 and VWF expression increased significantly in VTD but were similar to controls in VTD + DF. Separately, bortezomib was the main deleterious agent whereas dexamethasone showed no harmful effect. Leukocyte adhesion showed similar trends. VE-cadherin expression was lower in VTD and normalized in VTD + DF. EC permeability increased only with bortezomib. No changes were observed in oxidative stress markers. Our results demonstrate that bortezomib damages the endothelium, and DF prevents this effect. A better knowledge of the induction drugs impact will allow the design of measures to protect the endothelium.

Cancer-associated venous thromboembolism: Treatment and prevention with rivaroxaban

Cancer-associated venous thromboembolism (VTE) is a frequent, potentially life-threatening event that complicates cancer management. Anticoagulants are the cornerstone of therapy for the treatment and prevention of cancer-associated thrombosis (CAT); factor Xa-inhibiting direct oral anticoagulants (DOACs; apixaban, edoxaban, and rivaroxaban), which have long been recommended for the treatment of VTE in patients without cancer, have been investigated in this setting. The first randomized comparisons of DOACs against low-molecular-weight heparin for the treatment of CAT indicated that DOACs are efficacious in this setting, with findings reflected in recent updates to published guidance on CAT treatment. However, the higher risk of bleeding events (particularly in the gastrointestinal tract) with DOACs highlights the need for appropriate patient selection. Further insights will be gained from additional studies that are ongoing or awaiting publication. The efficacy and safety of DOAC thromboprophylaxis in ambulatory patients with cancer at a high risk of VTE have also been assessed in placebo-controlled randomized controlled trials of apixaban and rivaroxaban. Both studies showed efficacy benefits with DOACs, but both studies also showed a nonsignificant increase in major bleeding events while on treatment. This review summarizes the evidence base for rivaroxaban use in CAT, the patient profile potentially most suited to DOAC use, and ongoing controversies under investigation. We also describe ongoing studies from the CALLISTO (Cancer Associated thrombosis-expLoring soLutions for patients through Treatment and Prevention with RivarOxaban) program, which comprises several randomized clinical trials and real-world evidence studies, including investigator-initiated research.

Multiple Myeloma and Thrombosis: Prophylaxis and Risk Prediction Tools

Thromboembolism in multiple myeloma (MM) patients remains a common complication that renders the optimization of our thromboprophylaxis practice necessary. This review aims to make clear the need for the development of more accurate risk assessment tools and means of thrombosis prevention. Current clinical practice is guided by available guidelines published by the IMWG in 2014, but the extent to which these are implemented is unclear. Recently, several groups developed clinical scores for thrombosis risk in MM in an attempt to improve risk stratification, but these have not been validated or used in clinical practice so far. Research in this field is increasingly focusing on understanding the unique coagulation profile of the MM patient, and data on potential biomarkers that accurately reflect hypercoagulability is emerging. Finally, promising evidence on the effectiveness of direct oral anticoagulants (DOACs) in the context of thrombosis prevention in MM patients is increasingly becoming available. The critical appraisal of the above research areas will establish the necessity of combining disease-specific clinical risk factors with coagulation biomarkers to allow more effective risk stratification that will eventually lead to the reduction of this significant complication. Results from ongoing clinical trials on the role of DOACs are much anticipated.

Venous thromboembolism risk with contemporary lenalidomide-based regimens despite thromboprophylaxis in multiple myeloma: A systematic review and meta-analysis

BACKGROUND

Thromboprophylaxis is routinely used with lenalidomide-based regimens in multiple myeloma because of a substantial risk of venous thromboembolism (VTE). However, little is known about the incidence of VTE with contemporary lenalidomide-based regimens. The objective of the current study was to estimate the incidence of VTE despite thromboprophylaxis with currently used lenalidomide-based regimens in patients with myeloma.

METHODS

The Ovid MEDLINE, Embase, and Cochrane databases were queried from study inception to January 2019 for keywords to cover the following concepts: "lenalidomide," "venous thromboembolism," and "multiple myeloma." Phase 1, 2, and 3 clinical trials evaluating lenalidomide-based regimens with thromboprophylaxis were included. The pooled incidence rate of VTE was estimated using a random-effects model.

RESULTS

The search generated 1372 citations, with 51 clinical trials and 9069 patients included for analysis. The most common thromboprophylaxis agents were aspirin, low-molecular-weight heparin or warfarin, administered either per risk-stratification or at investigators' discretion. The pooled incidence of VTE in trials of patients who had newly diagnosed and relapsed/refractory myeloma was 6.2% (95% CI, 5.4%-7.1%) over median treatment durations ranging from 2 to 34 cycles, which translated into 1.2 VTE events per 100 patient-cycles (95% CI, 0.9-1.7 VTE events per 100 patient-cycles). Among contemporary regimens, the risk of VTE was low with combined lenalidomide and low-dose dexamethasone (0.2 [95% CI, 0.1-0.6] events/100 patient-cycles) and lenalidomide maintenance (0.0 [95% CI, 0.0-0.7] events per 100 patient-cycles). VTE risk was higher with combined lenalidomide and low-dose dexamethasone plus proteasome inhibitors (1.3 [95% CI, 0.7-2.3] events per 100 patient-cycles).

CONCLUSIONS

Despite adequate thromboprophylaxis, lenalidomide-based regimens have a substantial risk of VTE in controlled clinical trial settings. Further studies are needed on new thromboprophylaxis strategies with regimens that have a high VTE risk.

Apixaban for the prevention of thromboembolism in immunomodulatory-treated myeloma patients: Myelaxat, a phase 2 pilot study

The risk of venous thromboembolism (VTE) is higher in myeloma patients receiving immunomodulatory compounds. A VTE prophylaxis using low-molecular-weight heparin or aspirin is therefore proposed. Apixaban is an oral direct anti-Xa. Several studies have shown the efficacy and safety of apixaban in VTE prophylaxis compared to enoxaparin. The objective of this prospective phase 2 pilot study was to assess the risk of VTE and bleeding in patients with myeloma treated with immunomodulatory compounds lenalidomide (len) or thalidomide (thal), using apixaban in a preventive scheme. Myeloma patients requiring Melphalan-Prednisone-Thalidomide in the first line, or Lenalidomide-Dexamethasone in the relapse setting received apixaban, 2.5 mg x 2/day for 6 months. Venous (pulmonary embolism-PE, or symptomatic proximal or distal deep vein thrombosis-DVT, or all proximal asymptomatic events detected by systematic proximal bilateral compression ultrasound) or arterial thrombotic events, and bleeding events (ISTH 2005) were registered. One hundred and four patients were enrolled (mean age 69.8 ± 7.8 years), 11 in first line and 93 in relapse. Two venous thrombotic events were observed, for example, an asymptomatic proximal DVT and a symptomatic distal DVT, in the context of apixaban stopped 14 days before, due to lenalidomide-induced thrombocytopenia. No PE or arterial cardiovascular events were reported. Only one major and 11 CRNM hemorrhages were reported. These data must now be confirmed on a randomized large study.