Thrombosis In Multiple Myeloma Research Articles

Bleeding and Thrombosis in Multiple Myeloma: Platelets as Key Players during Cell Interactions and Potential Use as Drug Delivery Systems

Multiple myeloma (MM) is a hematological malignancy originated in the bone marrow and characterized by unhindered plasma cell proliferation that results in several clinical manifestations. Although the main role of blood platelets lies in hemostasis and thrombosis, platelets also play a pivotal role in a number of other pathological conditions. Platelets are the less-explored components from the tumor microenvironment in MM. Although some studies have recently revealed that MM cells have the ability to activate platelets even in the premalignant stage, this phenomenon has not been widely investigated in MM. Moreover, thrombocytopenia, along with bleeding, is commonly observed in those patients. In this review, we discuss the hemostatic disturbances observed in MM patients and the dynamic interaction between platelets and myeloma cells, along with present and future potential avenues for the use of platelets for diagnostic and therapeutic purposes.

Patients with multiple myeloma and monoclonal gammopathy of undetermined significance have variably increased thrombin generation and different sensitivity to the anticoagulant effect of activated protein C

BackgroundPatients with multiple myeloma (MM) are at high risk of thrombosis especially when receiving immunomodulatory therapy. Thrombotic risk in patients with monoclonal gammopathy of undetermined significance (MGUS) may also be increased. Although activated protein C (APC) resistance has been linked to an increased risk of thrombosis in MM, little is known about how APC influences thrombotic risk in MGUS. We compared thrombin generation (TG) in MM and MGUS patients to that of healthy controls (HCs) and investigated the exogenous effect of APC on TG in these groups. MethodsHemostasis tests including factor VIII (FVIII) and von Willebrand factor (vWF) levels were measured in platelet-poor plasma in 14 untreated MM patients, 34 MGUS patients, and 30 age and sex-matched HCs. TG assay was performed with or without the addition of APC. ResultsPeak thrombin and velocity index were significantly higher in MM and MGUS patients compared to HCs, while MM patients also had elevated endogenous thrombin potential (ETP). In MGUS cases, ETP and peak thrombin values significantly correlated with FVIII and vWF levels. In the presence of APC, peak thrombin and ETP were reduced in MGUS and control plasmas whereas lagtime and time to peak were significantly prolonged. In contrast, adding APC to MM plasma had no effect on any TG parameters. ConclusionsHypercoagulability was observed in MM and even in MGUS cases with very low monoclonal protein concentration. In MM patients, APC had no effect on TG, but it attenuated TG in MGUS patients.

Thrombosis in multiple myeloma: Risk estimation by induction regimen and association with overall survival.

Lenalidomide-containing (R) triplet and quadruplet regimens are the standard of care for multiple myeloma (MM) and have been shown to increase the risk of thrombosis. The association between thromboembolism (TE) and survival in the novel multidrug era is not yet delineated. In this study, we evaluated the incidence of TE during the first year of MM diagnosis, its association with the type of induction regimen, and its impact on overall survival. We studied 672 newly diagnosed MM (NDMM) patients who received a triplet or quadruplet lenalidomide-based induction at the Mayo Clinic, Rochester. TE was diagnosed in 83 patients (12.4%). Of these, 56 (8.3%) had a deep venous thrombosis (DVT), 23 (3.4%) had a pulmonary embolism (PE) with or without the DVT, and 4 (0.6%) patients had a stroke. Carfilzomib-Rd (KRd) had the highest risk of TE (21.1%, 18/85), followed by quadruplets (11.1%, 5/45), bortezomib-Rd (9.6%, 51/531), and 0/11 (0%), treated with other lenalidomide-containing regimens. The difference in TE risk between KRd and the other regimens was statistically significant (OR=2.6, p < .01). Nine patients developed a TE before being exposed to any treatment. Survival was significantly lower among patients that developed a TE (66 vs. 133 months, p < .01). The association of TE with reduced survival demonstrated in univariate analysis (HR=2.2, 95% CI=1.6-3.3) was maintained in the multivariable analysis adjusted for high-risk interphase fluorescence in situ hybridization (FISH), sex, age, receipt of an upfront transplant, the response at induction, and the International Staging System (ISS) (HR=2.61, CI=1.74-3.9). We conclude that TE is an important aspect of MM management, and effective management is especially relevant in the novel treatment era.

P-126: Thrombosis in multiple myeloma – risk estimation by induction regimen and association with overall survival

P-126: Thrombosis in multiple myeloma – risk estimation by induction regimen and association with overall survival

Thrombosis in multiple myeloma: risk stratification, antithrombotic prophylaxis, and management of acute events. A consensus-based position paper from an ad hoc expert panel.

The introduction of new therapeutic agents for multiple myeloma (MM), including proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies, has improved the outcomes of patients but, in parallel, has changed the frequency and epidemiology of thrombotic events. Thrombosis is now a significant cause of morbidity and mortality in MM patients, and optimal thromboprophylaxis is far from being reached. Moving from the recognition that the above issue represents an unmet clinical need, an expert panel assessed the scientific literature and composed a framework of recommendations for improving thrombosis control in patients who are candidates for active treatment for MM. The panel generated key clinical questions using the criterion of clinical relevance through a Delphi process. It explored four domains, i.e., thrombotic risk factors and risk stratification, primary thromboprophylaxis, management of acute thrombotic events, and secondary thromboprophylaxis. The recommendations issued may assist hematologists in minimizing the risk of thrombosis and guarantee adherence to treatment in patients with MM who are candidates for active treatment.

Rivaroxaban for Improvement in Thromboembolism Outcomes in Patients with Multiple Myeloma on Lenalidomide-Based Therapy: The Rithmm Feasibility Pilot Trial

Rivaroxaban for Improvement in Thromboembolism Outcomes in Patients with Multiple Myeloma on Lenalidomide-Based Therapy: The Rithmm Feasibility Pilot Trial

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.

Prospective Study Reveals Increased Platelet Function Associated with Multiple Myeloma and Its Treatment

Background: Multiple Myeloma (MM) is a rare incurable bone marrow cancer characterised by a malignant proliferation of plasma cells. MM is usually preceded by a premalignant and benign Monoclonal Gammopathy of Undetermined Significance (MGUS). The incidence of arterial and venous thrombosis in MM is substantially higher than in the normal population, however the cause of this increased thrombosis risk and the impact of MM on platelet function is unclear. Treatments for both newly diagnosed and relapsed/refractory patients with MM include Immunomodulatory drugs (IMiDs) such as thalidomide/lenalidomide-based combinations. These treatments improve considerably patient outcomes, however iMiD treatment also increases the risk of thrombotic complications in these patients. Aims: In this prospective study we explored the impact of MM and its treatment on platelet function. Methods: High throughput functional analysis was performed using platelets from normal healthy controls (n=31) and patients with MGUS (n=18), smouldering multiple myeloma (SMM, n= 20), and MM (26). The MM group was further divided into 3 treatment cohorts; (1) no treatment, (2) treatment with proteasome inhibitor (PI) and dexamethasone (Dex), and (3) treatment with PI, Dex, immunomodulatory drug (iMiD) and direct oral anticoagulant. Platelet aggregation and activation (fibrinogen binding and P-selectin exposure) were measured in response to a concentration range of agonists including ADP, the thrombin receptor agonist TRAP-6, collagen, collagen-related peptide (CRP), a thromboxane receptor agonist U46619 and epinephrine. Cereblon protein was detected in platelet protein extracts by immunoblot analysis. Results: Consistent with previous reports, modestly increased VWF and factor VIII levels were detected in MM patients, but no additional differences in coagulation parameters were detected in patient groups compared to normal healthy controls (other than expected due to anticoagulant usage). Platelet aggregation in response to each agonist was increased significantly in the MM patient group compared to the normal healthy controls, suggesting that platelet reactivity is elevated in MM patients through a common mechanism that is shared by different activation pathways or the involvement of multiple mechanisms. P-selectin exposure on platelets from MM patients was not significantly different from normal healthy donors, indicating that enhanced platelet reactivity in MM is specifically through modulation of integrin αIIbβ3 activation, fibrinogen binding and therefore enhanced aggregation. The effects of treatment on platelet function in patients on iMiD vs. non iMiD treatment were assessed. In the iMiD treatment group, patient platelets aggregated in response to lower concentrations of ADP, collagen, epinephrine and CRP in samples taken post-treatment compared to those taken before and during treatment. This demonstrates an increased sensitivity to platelet activation in these patients induced by treatment. Immunoblot analysis revealed that platelets contain cereblon, a therapeutic target of lenalidomide. The potential direct effects of iMiDs on platelets in vitro was therefore explored. Lenalidomide treatment (10mM) increased the ability of platelets to aggregate in response to low concentrations of each agonist tested when compared to normal controls. Conclusions: Platelet reactivity is increased in multiple myeloma and increased further upon iMiD treatment. The presence of the key therapeutic target for iMiDs in platelets and the ability of lenalidomide to modulate platelet function directly, reveals new avenues for investigation to determine the underlying mechanism of action. Disclosures Laffan: CSL: Consultancy; Pfizer: Consultancy; Sobi: Consultancy; Roche: Consultancy; LFB: Consultancy; Shire: Consultancy; Octapharma: Consultancy; Bayer: Speakers Bureau; Roche-Chugai: Speakers Bureau; Takeda: Speakers Bureau; Leo-Pharma: Speakers Bureau; Pfizer: Speakers Bureau. Shapiro:Bayer: Consultancy, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; NovoNordisk: Consultancy, Speakers Bureau; Sobi: Consultancy, Speakers Bureau; Chugai/Roche: Consultancy, Speakers Bureau; Shire/Takeda: Consultancy, Speakers Bureau. Thakurta:Oxford University: Other: visiting professor; Bristol Myers Squibb: Current Employment, Current equity holder in publicly-traded company. Ramasamy:Takeda: Research Funding; Janssen: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Research Funding; Amgen: Research Funding; Amgen: Honoraria; Takeda: Honoraria; Sanofi: Honoraria; Oncopeptides: Honoraria; Takeda: Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Bristol Myers Squibb: Honoraria; Janssen: Membership on an entity's Board of Directors or advisory committees; Bristol Myers squibb: Membership on an entity's Board of Directors or advisory committees. Gibbins:Bristol Myers Squibb: Research Funding; Arena Pharmaceuticals: Research Funding.

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

Multiple myeloma is associated with a significant risk of venous thromboembolism (VTE), causing substantial levels of morbidity and mortality. The thrombogenicity of myeloma is multifactorial, with disease- and treatment-related factors playing important roles. Immunomodulatory drugs (IMiDs) and high-dose dexamethasone, in particular, are known to enhance the thrombotic potential of myeloma. For this reason, assessment of the VTE risk has long been advocated prior to treatment initiation in patients with myeloma requiring IMiD-based regimens. However, despite routine use of thromboprophylaxis, these patients can still develop VTE and its sequelae. The optimum choice and dose of thromboprophylactic drug is not entirely clear, and with this, there is growing interest regarding use of the direct oral anticoagulants in this setting. In this review we discuss the pathogenesis of thrombosis in multiple myeloma, its relation to some of the commonly used chemotherapeutic regimens, current risk stratification and the evidence supporting the different anticoagulants used as thromboprophylaxis. We propose an amended risk stratification, and consider management of challenging patients, including those with renal impairment and recurrent thrombosis.

Thrombosis in multiple myeloma

Reportedly, patients with cancer have an increased risk (four- to seven-fold) of developing thrombotic events (TEs) compared with healthy volunteers. Multiple myeloma (MM) is one of the neoplasms that exhibit a high incidence of TEs, and approximately 10% patients with MM develop TEs during their clinical courses. The underlying risk factors of TEs are classified into patient-, disease-, and treatment-related factors. Specific treatment-related risk factors comprise the use of immunomodulatory drugs combined with dexamethasone. As the occurrence of TE in patients hampers the treatment for MM itself, which results in unfavorable outcomes, elucidating TE pathogenesis and adequate prophylaxis for each patient are essential to prevent MM-related TEs.

Altered Endothelial Cells Properties and Platelets Activity in Treatment NaïVe Patients with Multiple Myeloma (MM ) and Non-Hodgkin Lymphoma (nHL): Association with Thromboembolic Complications

Multiple myeloma and non-Hodgkin lymphoma and its treatment are frequently associated with increased tromboembolic risk, particularly venous trromboembolism (VTE), cerebrovascular ischemic events and myocardial infarction. The incidence of thrombotic complications dramatically raise after highly prothrombotic therapeutic regimens e.g. thalidomide and lenalidomide in MM.The current study was designed to examine whether procoagulant microparticles (MPs) derived from endothelial cells (EMPs) and platelets (PMPs) constitute an enhanced risk for venous thrombosis in MM and nHL patients (pts).We studied 39 pts without history of VTE, 17/22 F/M, aged 24-84 years (mean=60,23±13,45). There were 25 MM pts (15 cases of IgG, 3 of IgA, 1 IgM, 2 non secretory MM, 3 LCD) and 14 nHL (6 cases of DLBCL, 2 anaplastic T cell lymphoma, 2 FL, 4 MCL). All patients underwent routine coagulation tests. Flow-cytometry was used for quantification of endothelial cell (CD133+) microparticles (EMPs) and platelet (CD61+) microparticles (PMPs). In all pts ultrasound examination of venous system of lower extremities was performed. Deep and superficial veins of both limbs were evaluated. Conventional and Doppler imagination, as well as elastography and options to detect microcalcifications (micropure) were used.The ultrasound examination revealed the presence of vein thrombosis in 18 pts (group I, n =18). 11 out of 18 pts with bilateral lesions in VSM (vena saphena magna, great saphenous vein) and lower leg veins or bilateral in VSM only comprised subgroup Ia. 7 pts with unilateral blood clots in VSM formed group Ib. Thrombosis was observed in 11 pts with MM and 7 with nHL, and bilateral thrombotic lesions were demonstrated in 6 MM and 5 nHL pts. The remaining 21 pts showed no thrombosis (group II). The most frequently thrombosis was observed in IgA-MM (3/3 pts), followed by IgG-MM. In nHL patients thrombosis was found the most frequently in DLBCL. Patients were divided into two groups according to the age: > 60 yrs and <60 yrs. Both in MM and nHL, thrombosis was more frequent in older patients.The mean percentage of EMPs (CD133+) was 1,44±1,22 (median 0,95, IQR 0,47-2,31), and it did not differ (p=0,83) between thrombotic (group I) (1,48±1,16) and non-thrombotic pts (group II) (1,46±1,31), however the greatest value was assessed in the subgroup Ia (1,74±1,26, p=0,3467). Also, there was a trend marked that EMP percentage was lower in MM patients (1,25±1,31) in comparison to nHL patients (1,76±1,04), p=0,0671 (UM-W test). EMP percentage did not differ according to sex and age.The percentage of PMPs (CD61+) was 12,06 ± 6,31 (median 10,88, IQR 8,35-15,90), and higher in group I (12,65±3,25) vs. group II (10,93±7,68), p=0,0459 (UM-W test), including subgroup Ia (13,05±3,66), p=0,0885 (UM-W test). The mean PMPs percentage was similar in MM (12,27±7,18) vs. nHL (11,70±4,71), and as EMPs percentage, did not differ according to sex and age.Mean plasma fibrinogen (FBG) concentration was 3,95±1,82 g/L and did not significantly differ in MM and nHL patients with and without thrombosis (3,84±1,68 vs. 4,10±2,06 g/L), also it has similar level in subgroup Ia (4,06±1,97 g/L). Mean D-dimer level was 2,29±4,15 mg/L (median 1,30, IQR 0,54-2,35), and there was not significantly different in patients with and without thrombosis (2,95±5,29 vs. 1,34±1,25 mg/L), moreover it was not elevated in subgroup Ia (1,96±1,02 mg/L). Type of the disease, sex as well as age did not influenced FBG and D-dimer levels.Venous thrombosis was confirmed in nearly half of patients with newly diagnosed patients with MM and n-HL. In patients with many thrombotic lesions elevated activity of platelets (PMPs) was observed, as well as a trend towards elevated activity of endothelial cells (EMPs). DisclosuresRobak:MorphoSys AG: Research Funding.

A Case of Internal Carotid Artery Thrombosis associated with Thalidomide Administration in Multiple Myeloma

Thalidomide is an effective chemotherapeutic agent used to achieve remission in multiple myeloma. However, its administration is associated with several adverse effects including venous thromboembolism, while arterial thrombosis has also, although rarely, been described in the literature. We report a case of internal carotid artery occlusion within 1 week of starting thalidomide with prophylactic low molecular weight heparin in a patient who had no other prothrombotic risk factors. It is not known why this complication occurs despite the administration of anticoagulant prophylaxis. The role of factor VIII, von Willebrand factor antigen levels and fibrinogen in multiple myeloma patients should be studied in order to determine if these factors should be targeted in future prophylactic treatment.LEARNING POINTSThalidomide increases risk of arterial thrombosis in multiple myeloma (MM), even if no other procoagulant risk factors are present.All patients starting thalidomide must be assessed before commencing venous thromboprophylaxis, although its efficacy in preventing arterial thrombosis has not yet been proven.Further research is required to target anti-thrombotic factors in order to prevent arterial thrombosis in patients with MM being treated with thalidomide and its derivatives.

Update of thrombosis in multiple myeloma

With the introduction of thalidomide and multi-agent chemotherapy in the treatment of multiple myeloma around 15years ago a strongly increased risk of venous thrombosis was observed. The occurrence of venous thrombosis in multiple myeloma is not only determined by the kind of treatment, but also by several other factors, including disease specific factors, patient-specific factors, changes in pro-and anticoagulant factors and fibrinolysis. Studies showed a prevalence of up to 25% in patients with newly diagnosed multiple myeloma. Therefore these patients nowadays receive prophylaxis with aspirin, low molecular weight heparin or warfarin in order to reduce the risk of venous thrombosis. It is however still debatable which patients should receive prophylaxis and what the best kind of prophylaxis is, considering both the risk of thrombosis and the risk of bleeding. In recent years several new anti-myeloma agents have been developed and investigated in large clinical studies. The risk of thrombosis using these new drugs seems less than with thalidomide and lenalidomide-based regimens. In this article an update on prevention and management of thrombotic events in patients with multiple myeloma is given.

Tissue Factor and Hematological Neoplasias

AbstractAbstract 5132There is a well- recognized correlation between cancer and aberrant hemostasis. Venous thromboembolism (VTE) in individuals with solid epithelial tumors has been associated with a poor prognosis, with more than three-fold higher risk of early death as compared to cancer patients without thrombosis. The expression of tissue factor (TF), a cell-surface membrane glycoprotein that triggers the activation of coagulation by cancer cells, is one of the main underlying mechanisms linking thrombosis and aggressive tumor behavior. TF is expressed in a variety of solid tumors in association with genetic events affecting oncogenes and tumor suppressor genes. However, the mechanisms of thrombosis in individuals with hematological malignancies may differ from those with solid tumors. We have previously shown that despite the high rate of thrombosis in multiple myeloma, malignant plasma cells only rarely express TF. We sought to determine TF gene (F3) and protein expression in hematological neoplasias. F3 expression profiling was studied on a variety of cell lines established from lymphoid and myeloid neoplasias available at Glaxo Smith Kline (GSK) Cancer Cell Line Genomic Profiling Dataset (https://array.nci.nih.gov/caarray/project/woost-00041). Interestingly, F3 expression was absent in all lymphoid neoplasias studied, in sharp contrast to acute myeloid leukemias (AML) and solid tumors, of which 30 and 90% expressed F3, respectively. Immunohistochemistry (IHC) confirmed the absence of TF protein expression in all indolent and high-grade B-cell lymphomas (99 patients, including germinal center and activated B-cell phenotype diffuse large B-cell lymphomas) and in all T-cell lymphomas/leukemias (20 patients) studied. IHC for TF was also negative in AML (11 patients) but positive in representative solid tumors (breast, pancreas, prostate), except for renal cell carcinoma which has been previously shown to lack TF. We propose that the pathogenesis of VTE associated with hematological neoplasias differs from that of solid tumors. Though TF from non-neoplastic cell sources may still be important for the prothrombotic state often seen in these patients, we show there is no evidence for a role of tumor-derived TF in the development of DVT, nor in neoplastic behavior. Thus, treatments directed against TF may not impact on prognosis in lymphoid, and non TF-expressing myeloid neoplasias. Disclosures:No relevant conflicts of interest to declare.

Thrombosis is associated with inferior survival in multiple myeloma

Patients with multiple myeloma are at an increased risk of venous thromboembolism and arterial thrombosis. We assessed the impact of venous and arterial thrombosis on survival in a population-based study of 9,399 multiple myeloma patients diagnosed in Sweden from 1987 to 2005. We found multiple myeloma patients with venous thromboembolism to have a higher mortality at 1-, 5-, and 10-years of follow up compared with those without, with hazard ratios of 2.9 (95% confidence interval (CI) 2.4-3.5), 1.6 (95% CI: 1.5-1.8), and 1.6 (95% CI: 1.4-1.7), respectively. There was an increase in risk of death among multiple myeloma patients with arterial thrombosis, with hazard ratios of 3.4 (95% CI: 3.0-3.8), 2.2 (95% CI: 2.0-2.3), and 2.1 (95% CI: 1.9-2.1), respectively. In landmark analyses at six months, early arterial but not venous thromboembolism was associated with a higher risk of death. Thus, in contrast to prior smaller studies, we found the development of thrombosis to be associated with significantly poorer survival. The prevention of thrombosis in multiple myeloma is an important goal in the management of these patients.

PL-17 Risk and management of thrombosis in multiple myeloma

Patients diagnosed with multiple myeloma have an increased risk of venous thrombosis. This may be due to various risk factors, including disease specific factors, changes in coagulation and fibrinolysis factors and circulating prothrombotic microparticles. More recent studies have indicated that also arterial thrombosis, including acute myocardial infarction and stroke do occur more frequently in these patients. Studies on etiological factors contributing to the development of thrombosis will be reviewed in this article. In addition we will focus on the prevention and management of arterial and venous thrombosis in patients with multiple myeloma.

Bleeding and Thrombosis in Multiple Myeloma and Related Plasma Cell Disorders

A variety of disease- and treatment-related factors affect the coagulation system and the risk of bleeding and thrombotic complications in patients with multiple myeloma (MM) and related plasma cell disorders (PCD). As commonly observed in other cancer settings, the malignant clone induces a cytokine environment responsible for a hypercoagulable state. The increase of blood viscosity and impairment of platelet and coagulation function due to circulating monoclonal proteins are considered key mechanisms in the hemostatic abnormalities frequently detected in patients with PCD. However, clinically significant bleeding is relatively rare and poorly correlated with these abnormalities. Management is often challenging because of the multifactorial pathogenesis and underestimation or misdiagnosis of acquired bleeding disorders, particularly acquired von Willebrand syndrome. In recent years, growing interest in thromboembolic risk has emerged after the introduction of novel and more effective antimyeloma agents (thalidomide and lenalidomide), which was associated with increased risk of venous thromboembolism, particularly when associated with dexamethasone and multiagent chemotherapy in newly diagnosed patients. The clinical impact of bleeding and thrombotic complications in patients with PCD, with emphasis on MM, will be discussed in this review, reporting the current knowledge about pathophysiologic mechanisms and implications for management.

Microparticle-associated tissue factor activity and venous thrombosis in multiple myeloma

Multiple myeloma (MM) is associated with an increased risk of venous thromboembolic (VTE) complications. Aim of this study was to measure microparticle-associated tissue factor (MP-TF) activity in patients with newly diagnosed MM before and after chemotherapy and to investigate whether MP-TF activity is associated with VTE. MP-TF activity was assessed in 122 newly diagnosed MM patients who were eligible for combination chemotherapy. MP-TF activity levels (17.6 fM Xa/min [8.6-33.2] (median [IQR]) were higher in untreated MM patients compared to normal healthy volunteers (4.1 fM Xa/min [2.3-6.6], p <0.001). MP-TF activity prior to the start of treatment was not different between patients who developed a VTE during follow-up (n=15) and those who did not (n=107). In 75 patients in whom plasma was obtained before and after chemotherapy, MP-TF activity decreased significantly (from 17.4 [10.2-32.8] to 12.0 [7.0-18.5] fM Xa/min, P=0.006). MP-TF activity remained, however, elevated in patients who developed VTE (15.1 [10.3-25.2]), in contrast to patients not developing VTE (11.4 [7.0-25.2], P<0.001). In conclusion, MP-TF activity is increased in patients with MM. Whether MP-TF activity has a pathogenetic role in VTE in MM patients remains to be established in future studies.

Hypercoagulability in Multiple Myeloma and Its Precursor State, Monoclonal Gammopathy of Undetermined Significance

Patients with multiple myeloma are at an increased risk of venous thromboembolism (VTE), especially when treated with the immunomodulatory drugs, thalidomide and lenalidomide, in combination with dexamethasone and/or chemotherapy. Several studies have shown that patients with multiple myeloma precursor disease (monoclonal gammopathy of undetermined significance [MGUS]) also have a higher risk of thrombosis compared to the general population. The underlying mechanisms for the hypercoagulable state are not completely understood. In this review, we discuss risk factors for thrombosis in multiple myeloma, as well as prophylactic strategies, the evidence for thrombosis among patients with MGUS, and proposed mechanisms for the hypercoagulability.

Thrombosis in Multiple Myeloma

Patients with multiple myeloma (MM) are at an increased risk of venous and arterial thrombosis. The pathogenesis remains unclear, but probably involves several factors such as activation of procoagulant factors, acquired activated protein C resistance, and inflammation. In addition to general risk factors for venous thromboembolism, such as older age, immobility, surgery, and inherited thrombophilia, there are some MM-specific and treatment-related factors that contribute to the increased risk. The risk for venous thromboembolism is high when patients are treated with thalidomide or lenalidomide in combination with dexamethasone or multi-agent chemotherapy. Thromboprophylaxis should be given in these settings. Which agent is the most appropriate is a matter of debate, but aspirin, low-molecular-weight heparin, and warfarin all seem to be effective. This review discusses risk factors for thromboembolism in MM and general, disease-specific and treatment-related mechanisms for thrombosis. Recommendations for thromboprophylaxis are described and treatment choices for venous thrombosis in MM patients are reviewed.