In vitro study of the hypercoagulable state in multiple myeloma patients treated or not with thalidomide

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.

Patients With Multiple Myeloma Have a Disbalanced Whole Blood Thrombin Generation Profile

Background

Multiple myeloma (MM) is associated with a high prevalence of bleeding and an increased risk of thrombo-embolism. MM patients have reduced platelet- and red blood cell (RBC) numbers in blood, which may indicate that the paradoxical hemostasis profile is a consequence of a disturbed platelet and RBC homeostasis.

Objectives

To get better insight in the disbalanced hemostasis of MM patients.

Methods

We conducted a case-control study on the whole blood (WB) coagulation profiles of 21 MM patients and 21 controls. We measured thrombin generation (TG) in WB and platelet poor plasma (PPP) of MM patients and controls.

Results

In WB-TG, we observed that the median time to the thrombin Peak was 52% longer in MM patients than in controls, while the median endogenous thrombin potential until the Peak (ETPp) was 39% higher in MM-patients than in controls. In line with these findings, the levels of platelets, RBCs, white blood cells and agonist induced platelet activation were decreased in MM patients compared to controls. The plasma TG experiments showed no differences between MM-patients and controls.

Conclusion

Patients with MM have a disturbed blood cell metabolism and a disbalanced WB-TG profile. This disbalance may explain the paradoxically high prevalence of bleeding symptoms in MM patients vs. an increased thrombosis risk. There was no disturbance observed in plasma TG, indicating that blood cells are the major determinants for the disbalanced hemostasis in MM patients.

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.

Plasma Levels of Vascular Endothelial Growth Factor and Selected Hemostatic Parameters in Association With Treatment Response in Multiple Myeloma

Multiple myeloma (MM) is a neoplastic plasma cell disorder characterized by the clonal proliferation of plasma cells in the bone marrow and presence of monoclonal protein in the blood or urine. Diverse hemostatic abnormalities have been reported in patients with myeloma which predispose the patient to bleeding and also thrombosis. The aim of this study was to measure the concentrations of serum levels of vascular endothelial growth factor, D-dimer, and von Willebrand factor in patients with newly diagnosed or relapsed multiple myeloma before treatment, during therapy, and after successful therapy. The working hypothesis was that all of these factors reflect the total body burden of tumor. Angiogenic and coagulation activity should therefore decrease after successful therapy. Our study indicates that selected prothrombotic abnormalities occur in patients with MM, which may contribute to the increased risk of venous thromboembolism observed in these patients. The levels of our 3 parameters were strongly elevated in patient with newly diagnosed MM and also in patients with clinical stage III based on International Staging System criteria. Furthermore, there was a correlation between prognostic disease stages in all study population. It would be appropriate to include angiogenic and coagulation parameters into prognostic parameters.

Phosphatidylserine-exposing cells contribute to the hypercoagulable state in patients with multiple myeloma

Multiple myeloma (MM) is characterized by an increased incidence of thromboembolic events, particularly when treated with immunomodulatory drugs (IMiDs) in combination with dexamethasone. The optimal prophylactic strategy to prevent the hypercoagulable state of patients with MM is still debated. The aim of the current study was to investigate the definitive role of phosphatidylserine (PS) in supporting procoagulant activity (PCA) in patients with MM. Patients with MM (n=20) and healthy subjects (n=15) were recruited for the present study. PS analyses were performed by flow cytometry and confocal microscopy. The PCA was evaluated by clotting time, purified coagulation complex assays and fibrin production assays. The percentage of PS+ blood cells was significantly higher in patients with MM than in healthy subjects. Additionally, the patient serum induced more PS exposure on endothelial cells (ECs) in vitro than serum from healthy subjects. Isolated blood cells from patients with MM and ECs cultured with patient serum in vitro demonstrated significantly shortened coagulation time, greatly intrinsic/extrinsic factor Xa generation and increased thrombin formation. In addition, the levels of PS+ erythrocytes, platelets, leukocytes, and ECs incubated with IMiDs and dexamethasone were higher than with IMiDs alone. The findings support the hypothesis that increased PS exposure on blood cells and ECs participates in the hypercoagulable state in patients with MM. Thus, blocking PS may be a novel therapeutic target for the prevention of thrombosis in these patients.

Thrombin generation as a predictor of thromboembolic events in multiple myeloma patients

BACKGROUND

Multiple myeloma (MM) is characterized by an increased incidence of thromboembolic events, especially when immunomodulatory drugs are used. Currently, our ability to predict these thrombotic events is limited. We hypothesized that global coagulation tests may be predictive of thrombotic events in MM patients.

METHODS

Blood samples were taken from 36 MM patients before and during routine treatment. Thrombin generation (TG) tests including endogenous thrombin potential (ETP) and peak height were analyzed.

RESULTS

Patients were followed for a median of 2.5years. Those who developed thrombotic events were characterized by significantly higher ETP and peak height values compared to those who did not (P=0.001). In these patients, we identified a gradual increase in TG parameters that preceded the thrombotic event. Anticoagulation therapy was associated with a significant decrease in ETP and peak height values (P<0.001). There was no statistically significant difference in TG parameters between newly diagnosed MM patients and healthy subjects, as well as between MM patients prior to and during chemotherapy.

CONCLUSIONS

TG tests might predict thrombotic events in MM patients. Thus, TG tests may be incorporated into decision-making protocols of prophylactic anticoagulant therapy in MM patients.

Baseline and treatment-related changes in thrombin generation in patients with multiple myeloma

The prothrombotic risk in multiple myeloma (MM) could be potentially assessed by thrombin generation (TG) assays. TG was performed using Calibrated Automated Thrombography with 5 and 1 pM tissue factor. We compared baseline TG among 24 MM patients, 19 MGUS, and 50 healthy controls, and assessed change in TG in MM patients during the initial treatment period at 1, 2, and 3 months. MM subjects demonstrated increased FVIII and VWF:Ag levels pretreatment, and a prothrombotic TG phenotype with increased velocity index, reduced lag time and time-to-peak, and increased resistance to thrombomodulin inhibition. There were no significant changes in TG with treatment for the majority of parameters, however, MM subjects exhibited persistent elevation of velocity index throughout treatment. Two subjects developed thrombosis during the study period despite thromboprophylaxis. This study provides information on the optimal conditions for examining TG as a predictor of thrombotic risk in MM patients.

Microparticle bearing tissue factor: a link between promyelocytic cells and hypercoagulable state

Patients with hematological malignancies have a 28-fold increased risk of venous thromboembolism (VTE). Among patients with acute myelogenous leukemia (AML), the 2-year cumulative incidence of VTE is 5.2%. Several studies suggest that microvesicles (MVs) harboring TF may play a role in VTE and disseminated intravascular coagulation (DIC) in acute promyelocytic leukemia (APL). The aim of this study was to assess the capacity of untreated (APL) cells to shed procoagulant MVs. APL cells (NB4 and HL-60 cell lines) and MVs were separated by filtration (0.1-0.22-0.45-0.65 μm). The procoagulant activity (PCA) was assessed by thrombin generation assay (TGA). Alternatively, MVs were incubated with anti-Tissue Factor (TF) antibodies, with annexin V to assess the contribution of TF and phospholipids (PL) to the PCA, respectively. NB4 cells had a high PCA mainly triggered by MVs of size under 0.45 μm. The PCA of MVs was related to the expression of active TF and PL. HL-60 cells had a weaker PCA since TF is mostly present in its inactive form. Moreover, HL-60 do not produce MVs<0.65 μm associated with PCA. MVs could have a predicting value for VTE and DIC in patients with acute promyelocytic leukemia and could inform physicians about the optimal use of a thromboprophylaxis.

Hemostatic changes after 1 month of thalidomide and dexamethasone therapy in patients with multiple myeloma

Thromboembolic events (TEE) are a serious clinical problem in multiple myeloma (MM) patients receiving thalidomide (T). Thirty-one MM patients were tested on diagnosis and after 2 and 4 weeks of therapy with T alone, or T in combination with dexamethasone (TD). Closure time (CT) in PFA-100 and P-selectin expression were assessed, as well as plasma levels of thrombin-antithrombin complexes (TAT), D-dimer (DD), soluble thrombomodulin (sTM) and von Willebrand factor antigen (vWF:Ag), along with the activity of coagulation factor VII and factor VIII. The concentration of vascular endothelial growth factor and its type 1 and 2 receptors were also assayed. On diagnosis, significantly prolonged median CT with both used cartridges, elevated P-selectin expression, DD concentration, TAT, vWF:Ag and factor VIII and factor VII activity were seen in the patient group as compared to controls. Therapy with these regimens caused marked shortening of CT with both cartridges. Treatment with TD leads to the significant increase in CD62P expression on platelets. Median TAT value increased significantly in relation to baseline after therapy with both regimens. Factor VIII activity exceeded 150 % in all patients after 2 weeks of TD therapy and was markedly elevated compared to baseline. One month of TD therapy significantly increased sTM concentration. These results demonstrate the enhanced platelet and coagulation system activation already present in MM patients on diagnosis, which is further increased by antimyeloma therapy. These changes are more pronounced after TD therapy and may promote TEE. Tested angiogenesis marker levels are elevated already on diagnosis, do not change after therapy and have no significant impact on the coagulation system in patients with MM.

Low venous thromboembolic risk with bortezomib in multiple myeloma and potential protective effect with thalidomide/lenalidomide-based therapy: review of data from phase 3 trials and studies of novel combination regimens

Patients with multiple myeloma (MM) are at elevated risk of venous thromboembolism (VTE), specifically deep vein thrombosis (DVT) and pulmonary embolism (PE). VTE risk in MM is increased by various patient- and disease-related factors. The type of anti-MM therapy represents a key factor, with a substantially elevated VTE risk in patients treated with the immunomodulatory drugs (IMiDs) thalidomide or lenalidomide in combination with dexamethasone and/or chemotherapy; VTE risk with lenalidomide-dexamethasone is further increased with concomitant erythropoietin. By contrast, treatment with the proteasome inhibitor bortezomib, alone or in combination, does not increase VTE risk; rates of DVT/PE do not appear affected by the use of erythropoiesis-stimulating agents. Bortezomib has shown antihemostatic effects in patients with relapsed or refractory MM, which supports that it exerts antithrombotic actions and thus potentially provides a protective effect in combination with regimens with an elevated VTE risk. Herein, we review data from phase 3 trials of bortezomib- and/or IMiD-based therapy in frontline MM, together with other studies of novel combination regimens. Despite the confounding effect of variable VTE prophylaxis, bortezomib-based regimens were typically associated with DVT/PE rates of ≤5%, similar to those seen with melphalan-prednisone and dexamethasone, whereas IMiD-based bortezomib-free regimens were generally associated with higher rates. Direct comparisons of regimens of thrombogenic potential with or without bortezomib demonstrated lower VTE risk with bortezomib. Between-study comparisons of VTE risk support these findings. Taken together, these data confirm the low VTE risk associated with bortezomib and support a potential protective effect of bortezomib in combination with IMiD-based regimens associated with elevated VTE risk.

Thalidomide effect in endothelial cell of acute radiation proctitis

AIM: To determine whether thalidomide prevents microvascular injury in acute radiation proctitis in white rats.

METHODS: Fourteen female Wistar rats were used: six in the radiation group, six in the thalidomide group, and two in normal controls. The radiation and thalidomide groups were irradiated at the pelvic area using a single 30 Gy exposure. The thalidomide (150 mg/kg) was injected into the peritoneum for 7 d from the day of irradiation. All animals were sacrificed and the rectums were removed on day 8 after irradiation. The microvessels of resected specimens were immunohistochemically stained with thrombomodulin (TM), von Willebrand Factor (vWF), and vascular endothelial growth factor (VEGF).

RESULTS: The microscopic scores did not differ significantly between the radiation and thalidomide groups, but both were higher than in the control group. Expression of TM was significantly lower in the endothelial cells (EC) of the radiation group than in the control and thalidomide groups (P < 0.001). The number of capillaries expressing vWF in the EC was higher in the radiation group (15.3 ± 6.8) than in the control group (3.7 ± 1.7), and the number of capillaries expressing vWF was attenuated by thalidomide (10.8 ± 3.5, P < 0.001). The intensity of VEGF expression in capillaries was greater in the radiation group than in the control group and was also attenuated by thalidomide (P = 0.003).

CONCLUSION: The mechanisms of acute radiation-induced proctitis in the rats are related to endothelial cell injury of microvessel, which may be attenuated with thalidomide.