scholarly journals Beyond plasma exchange: novel therapies for thrombotic thrombocytopenic purpura

Hematology ◽  
2018 ◽  
Vol 2018 (1) ◽  
pp. 539-547 ◽  
Author(s):  
Kathryn Dane ◽  
Shruti Chaturvedi
Keyword(s):  
Plasma Exchange ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Relapse Prevention ◽  
Tissue Injury ◽  
Novel Therapies ◽  
Thrombocytopenic Purpura ◽  
Platelet Recovery ◽  
Adamts13 Deficiency ◽  
Prophylactic Use ◽  
Von Willebrand

Abstract The advent of plasma exchange has dramatically changed the prognosis of acute thrombotic thrombocytopenic purpura (TTP). Recent insights into TTP pathogenesis have led to the development of novel therapies targeting pathogenic anti-ADAMTS13 antibody production, von Willebrand factor (VWF)–platelet interactions, and ADAMTS13 replacement. Retrospective and prospective studies have established the efficacy of rituximab as an adjunct to plasma exchange for patients with acute TTP, either upfront or for refractory disease. Relapse prevention is a major concern for survivors of acute TTP, and emerging data support the prophylactic use of rituximab in patients with persistent or recurrent ADAMTS13 deficiency in clinical remission. Capalcizumab, a nanobody directed against domain A1 of VWF that prevents the formation of VWF–platelet aggregates, recently completed phase 2 (TITAN) and 3 (HERCULES) trials with encouraging results. Compared with placebo, caplacizumab shortened the time to platelet recovery and may protect against microthrombotic tissue injury in the acute phase of TTP, though it does not modify the underlying immune response. Other promising therapies including plasma cell inhibitors (bortezomib), recombinant ADAMTS13, N-acetyl cysteine, and inhibitors of the VWF–glycoprotein Ib/IX interaction (anfibatide) are in development, and several of these agents are in prospective clinical studies to evaluate their efficacy and role in TTP. In the coming years, we are optimistic that novel therapies and international collaborative efforts will usher in even more effective, evidence-based approaches to address refractory acute TTP and relapse prevention.

scholarly journals Pathophysiology of thrombotic thrombocytopenic purpura

Blood ◽  
2017 ◽  
Vol 130 (10) ◽  
pp. 1181-1188 ◽  
Author(s):  
J. Evan Sadler
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Tissue Injury ◽  
Preventive Therapy ◽  
Neurological Deficits ◽  
Autoantibody Production ◽  
Thrombocytopenic Purpura ◽  
Adamts13 Deficiency ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract The discovery of a disintegrin-like and metalloproteinase with thrombospondin type 1 motif, member 13 (ADAMTS13) revolutionized our approach to thrombotic thrombocytopenic purpura (TTP). Inherited or acquired ADAMTS13 deficiency allows the unrestrained growth of microthrombi that are composed of von Willebrand factor and platelets, which account for the thrombocytopenia, hemolytic anemia, schistocytes, and tissue injury that characterize TTP. Most patients with acquired TTP respond to a combination of plasma exchange and rituximab, but some die or acquire irreversible neurological deficits before they can respond, and relapses can occur unpredictably. However, knowledge of the pathophysiology of TTP has inspired new ways to prevent early deaths by targeting autoantibody production, replenishing ADAMTS13, and blocking microvascular thrombosis despite persistent ADAMTS13 deficiency. In addition, monitoring ADAMTS13 has the potential to identify patients who are at risk of relapse in time for preventive therapy.

scholarly journals Von Willebrand factor, ADAMTS13, and thrombotic thrombocytopenic purpura

Blood ◽  
2008 ◽  
Vol 112 (1) ◽  
pp. 11-18 ◽  
Author(s):  
J. Evan Sadler
Keyword(s):  
Plasma Exchange ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Von Willebrand Factor ◽  
Unanswered Question ◽  
Thrombocytopenic Purpura ◽  
The Past ◽  
Adamts13 Deficiency ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Intensive Immunosuppressive Therapy

Abstract Discoveries during the past decade have revolutionized our understanding of idiopathic thrombotic thrombocytopenic purpura (TTP). Most cases in adults are caused by acquired autoantibodies that inhibit ADAMTS13, a metalloprotease that cleaves von Willebrand factor within nascent platelet-rich thrombi to prevent hemolysis, thrombocytopenia, and tissue infarction. Although approximately 80% of patients respond to plasma exchange, which removes autoantibody and replenishes ADAMTS13, one third to one half of survivors develop refractory or relapsing disease. Intensive immunosuppressive therapy with rituximab appears to be effective as salvage therapy, and ongoing clinical trials should determine whether adjuvant rituximab with plasma exchange also is beneficial at first diagnosis. A major unanswered question is whether plasma exchange is effective for the subset of patients with idiopathic TTP who do not have severe ADAMTS13 deficiency.

Platelets: Thrombotic Thrombocytopenic Purpura

Hematology ◽  
2002 ◽  
Vol 2002 (1) ◽  
pp. 315-334 ◽  
Author(s):  
James N. George ◽  
J. Evan Sadler ◽  
Bernhard Lämmle
Keyword(s):  
Plasma Exchange ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Clinical Approach ◽  
Adamts13 Activity ◽  
Extensive Experience ◽  
Thrombocytopenic Purpura ◽  
Severe Deficiency ◽  
Adamts13 Deficiency ◽  
And Function ◽  
Von Willebrand

Abstract Abnormalities of plasma von Willebrand factor (VWF) have been recognized to be associated with thrombotic thrombocytopenic purpura (TTP) for over 20 years. Patients with chronic, relapsing TTP have VWF multimers that are larger than normal, similar in size to those secreted by cultured endothelial cells. Recent observations have documented that a deficiency of a VWF-cleaving protease (termed ADAMTS13) may be responsible for the presence of these unusually large VWF multimers. Multiple mutations of the ADAMTS13 gene can result in ADAMTS13 deficiency and cause congenital TTP; autoantibodies neutralizing ADAMTS13 protease activity have been associated with acquired TTP. In Section I, Dr. Evan Sadler reviews the structure, biosynthesis, and function of the ADAMTS13 protease. He describes the mutations that have been identified in congenital TTP and describes the relationship of ADAMTS13 deficiency to the development of both congenital and acquired TTP. Dr. Sadler postulates that the development of TTP may be favored by conditions that combine increased VWF secretion, such as during the later stages of pregnancy, and decreased ADAMTS13 activity. In Section II, Dr. Bernhard Lämmle describes the assay methods for determining ADAMTS13 activity. Understanding the complexity of these methods is essential for understanding the difficulty of assay performance and the interpretation of assay data. Dr. Lämmle describes his extensive experience measuring ADAMTS13 activity in patients with TTP as well as patients with acute thrombocytopenia and severe illnesses not diagnosed as TTP. His data suggest that a severe deficiency of ADAMTS13 activity (< 5%) is a specific feature of TTP. However, he emphasizes that, although severe ADAMTS13 deficiency may be specific for TTP, it may not be sensitive enough to identify all patients who may be appropriately diagnosed as TTP and who may respond to plasma exchange treatment. In Section III, Dr. James George describes the evaluation and management of patients with clinically suspected TTP, as well as adults who may be described as having hemolytic-uremic syndrome (HUS). Dr. George presents a classification of TTP and HUS in children and adults. Appropriate evaluation and management are related to the clinical setting in which the diagnosis is considered. A clinical approach is described for patients in whom the diagnosis of TTP or HUS is considered (1) following bone marrow transplantation, (2) during pregnancy or the postpartum period, (3) in association with drugs which may cause TTP either by an acute immune-mediated toxicity or a dose-related toxicity, (4) following a prodrome of bloody diarrhea, (5) in patients with autoimmune disorders, and (6) in patients with no apparent associated condition who may be considered to have idiopathic TTP. Patients with idiopathic TTP appear to have the greatest frequency of ADAMTS13 deficiency and appear to be at greatest risk for a prolonged clinical course and subsequent relapse. Management with plasma exchange has a high risk of complications. Indications for additional immunosuppressive therapy are described.

scholarly journals Treatment of thrombotic thrombocytopenic purpura beyond therapeutic plasma exchange

Hematology ◽  
2015 ◽  
Vol 2015 (1) ◽  
pp. 637-643 ◽  
Author(s):  
Paul Coppo ◽  
Antoine Froissart
Keyword(s):  
Plasma Exchange ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Survival Rates ◽  
Therapeutic Plasma Exchange ◽  
Response To Treatment ◽  
Thrombocytopenic Purpura ◽  
Therapeutic Landscape ◽  
Life Threatening ◽  
Adamts13 Deficiency ◽  
Von Willebrand

Abstract Daily therapeutic plasma exchange (TPE) transformed the historically fatal prognosis of acquired, anti-ADAMTS13 antibody-mediated thrombotic thrombocytopenic purpura (TTP), leading to the current overall survival rates of 80%-85%. However, relapses occur in ∼40% of patients and refractory disease with fatal outcomes still occurs. In this context, the introduction of rituximab has probably been the second major breakthrough in TTP management. Rituximab is now routinely recommended during the acute phase, typically in patients with a suboptimal response to treatment, or even as frontline therapy, with high response rates. In more severe patients, salvage strategies may include twice-daily TPE, pulses of cyclophosphamide, vincristine, as well as splenectomy in more desperate cases. In this life-threatening disease, relapse prevention represents a major goal. Persistent severe acquired ADAMTS13 deficiency in patients who are otherwise in remission is associated with a high risk of relapse and preemptive treatment with rituximab may be considered in this context. In the coming years, the TTP therapeutic landscape should be enriched by original strategies stemming from clinical experience and new agents that are currently being evaluated in large, ideally international, clinical trials. Promising agents under evaluation include N-acetylcysteine, bortezomib, recombinant ADAMTS13, and inhibitors of the glycoprotein-Ib/IX-von Willebrand factor axis.

scholarly journals Application of SELDI-TOF mass spectrometry in clinical evaluation of thrombotic thrombocytopenic purpura

2006 ◽  
Vol 20 (5-6) ◽  
pp. 219-227
Author(s):  
Haifeng M. Wu ◽  
Spero R. Cataland ◽  
Michael Bissell ◽  
Ming Jin
Keyword(s):  
Mass Spectrometry ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Rapid Determination ◽  
Correct Diagnosis ◽  
Thrombocytopenic Purpura ◽  
Autoimmune Antibodies ◽  
Adamts13 Deficiency ◽  
Rapid Purification ◽  
Von Willebrand

Surface Enhanced Laser Desorption/Ionization Time Of Flight (SELDI-TOF) mass spectrometry is characterized by integration of mass spectrometry with surface chemistry, which gives rise to rapid purification and subsequent determination of protein/peptide analytes. There are several surface matrices, named proteinChips, available for analyzing a particular analyte or a subset of biomolecules in biological samples. Each proteinChip has a unique surface property suitable for fractionation of a specific group of molecules. This article demonstrates the application of SELDI-TOF for the analysis of a cleaved peptide (Mr7739 daltons) from von Willebrand Factor by a metalloproteinase, ADAMTS13. Deficiency of ADAMTS13 is a known primary risk factor for the devastating hematological disorder, Thrombotic thrombocytopenic purpura (TTP). Rapid determination of ADAMTS13 activity helps clinicians tremendously in making the correct diagnosis and initiating timely therapy. Most patients with TTP are acquired cases who exhibit a production of autoimmune antibodies against ADAMTS13 protease. TTP's clinical course is critically controlled by the autoantibody's ability to inhibit ADAMTS13 function. Thus, a second SELDI-TOF based test has been devised to measure ADAMTS13 autoantibody activity for the evaluation of TTP disease activity. In conclusion, the unique features of SELDI-TOF which allow for the examination of the role of key proteases in disease processes have opened up new doors for the clinical application of mass spectrometer based techniques.

Thrombotic Thrombocytopenic Purpura Misdiagnosed As Autoimmune Cytopenia: Causes of Diagnostic Errors and Consequence on Outcome. Experience of the French Thrombotic Microangiopathies Reference Centre

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3730-3730
Author(s):  
Maximilien Grall ◽  
Ygal Benhamou ◽  
Elie Azoulay ◽  
Eric Mariotte ◽  
Lionel Galicier ◽  
...  
Keyword(s):  
Organ Failure ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Conflicts Of Interest ◽  
Diagnostic Errors ◽  
Hemoglobin Level ◽  
Thrombocytopenic Purpura ◽  
Platelet Recovery ◽  
Reference Centre ◽  
Adamts13 Deficiency ◽  
The Impact

Abstract Introduction: Thrombotic thrombocytopenic purpura (TTP) is a life threatening disease defined by the association of a hemolytic mechanical anemia, a profound thrombopenia and organ failure with a severe ADAMTS13 deficiency. A rapid diagnosis represents a major goal and sources of misdiagnosis need to be identified to avoid diagnostic wandering and delayed adapted treatment that may translate in increased morbi-mortality. The main objective of this study is to describe the characteristics of TTP initially misdiagnosed and analyse the impact of a late diagnosis on patient's outcomes. Methods: From May 2000 to May 2014, all patients with acquired TTP and severe ADAMTS13 deficiency enrolled prospectively in the French TMA Reference Centre registry were included. A misdiagnosis was retained if initial diagnosis was not TTP and if patients did not receive TPE as initial treatment. Results: Among the 423 studied patients, 84 (20%) were initially misdiagnosed and not received plasma exchange. Main diagnostic errors were attributed to an Evans syndrome and an auto-immune thrombopenic purpura in 51% and 37% of cases respectively. Median time to diagnosis was longer in the misdiagnosed group than in the accurately diagnosed (5 [IQR, 2-8] vs. 1 [IQR, 0-3] days, P=.008). At admission, compared to the accurately diagnosed patients, misdiagnosed patients had a higher rate of low or undetectable schizocytosis (57.5% vs. 32%, P=.001), higher hemoglobin level (8.4 [IQR, 6.7-9.7] g/dl vs. 7.7 [IQR, 6.5-9.1] g/dl, P=.008) and rate of positive DAT (18% vs. 4%, P=.008). Anti-nuclear antibodies (65% vs. 51%, P=.045) and an associated auto-immune disease (24% vs. 13%, P=.017) were also more frequent. In multivariate analysis, a positive DAT and hemoglobin level were retained as risk factor (OR= 8.71, 95% CI [1.759-43.181], P=.008 and OR= 1.27, 95% CI [1.002-1.602], P=.048), respectively. Platelet count recovery over time was significantly longer in the misdiagnosed group (log-rank test: P=.041) without any consequence on overall mortality, exacerbation and relapse. However, specific causes of death probably differed between groups: in the accurately diagnosed group, patients died more frequently on early stage from a fulminant form of TTP within the first week, whereas in the misdiagnosed group patients died later (13 [IQR, 3-20] vs. 6 [IQR, 2-9] days; P=.023), had less organ involvement at early diagnosis (49% vs.64%, P=.019) and received more salvage therapies (80% vs. 35%, P=.009), suggesting that prognosis could have been improved with an earlier treatment. Conclusion: TTP is frequently misdiagnosed with auto-immune cytopenias and usual biological parameters may be initially absent. In a context of hemolysis and thrombocytopenia, a low or undetectable rate of schizocytosis at admission, and a positive DAT should not rule out the diagnosis of TTP, especially when associated with organ failure. A rapid accurate diagnosis of TTP may result in a shorter time to platelet recovery and could improve prognosis. Disclosures No relevant conflicts of interest to declare.

FRETS-VWF73 rather than CBA assay reflects ADAMTS13 proteolytic activity in acquired thrombotic thrombocytopenic purpura patients

2014 ◽  
Vol 112 (08) ◽  
pp. 297-303 ◽  
Author(s):  
Ilaria Mancini ◽  
Carla Valsecchi ◽  
Luca Lotta ◽  
Louis Deforche ◽  
Silvia Pontiggia ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Proteolytic Activity ◽  
Binding Activity ◽  
Adamts13 Activity ◽  
Flow Conditions ◽  
Thrombocytopenic Purpura ◽  
Severe Deficiency ◽  
Adamts13 Deficiency ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryCollagen-binding activity (CBA) and FRETS-VWF73 assays are widely adopted methods for the measurement of the plasmatic activity of ADAMTS13, the von Willebrand factor (VWF) cleaving-protease. Accurately assessing the severe deficiency of ADAMTS13 is important in the management of thrombotic thrombocytopenic purpura (TTP). However, non-concordant results between the two assays have been reported in a small but relevant percentage of TTP cases. We investigated whether CBA or FRETS-VWF73 assay reflects ADAMTS13 proteolytic activity in acquired TTP patients with non-concordant measurements. Twenty plasma samples with non-concordant ADAMTS13 activity results, <10% using FRETS-VWF73 and ≥20% using CBA, and 11 samples with concordant results, <10% using either FRETS-VWF73 and CBA assays, were analysed. FRETS-VWF73 was performed in the presence of 1.5 M urea. ADAMTS13 activities were also measured under flow conditions and the VWF multimer pattern was defined in order to verify the presence of ultra-large VWF due to ADAMTS13 deficiency. In FRETS-VWF73 assay with 1.5 M urea, ADAMTS13 activity significantly increased in roughly 50% of the samples with non-concordant results, whereas it remained undetectable in all samples with concordant measurements. Under flow conditions, all tested samples showed reduced ADAMTS13 activity. Finally, samples with non-concordant results showed a ratio of high molecular weight VWF multimers higher than normal. Our results support the use of FRETS-VWF73 over CBA assay for the assessment of ADAMTS13 severe deficiency and indicate urea as one cause of the observed differences.

von Willebrand factor cleaving protease (ADAMTS13) is deficient in recurrent and familial thrombotic thrombocytopenic purpura and hemolytic uremic syndrome

Blood ◽  
2002 ◽  
Vol 100 (3) ◽  
pp. 778-785 ◽  
Author(s):  
Giuseppe Remuzzi ◽  
Miriam Galbusera ◽  
Marina Noris ◽  
Maria Teresa Canciani ◽  
Erica Daina ◽  
...  
Keyword(s):  
Hemolytic Uremic Syndrome ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Acute Phase ◽  
Von Willebrand Factor ◽  
Adamts13 Activity ◽  
Thrombocytopenic Purpura ◽  
Uremic Syndrome ◽  
Adamts13 Deficiency ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Whether measurement of ADAMTS13 activity may enable physicians to distinguish thrombotic thrombocytopenic purpura (TTP) from hemolytic uremic syndrome (HUS) is still a controversial issue. Our aim was to clarify whether patients with normal or deficient ADAMTS13 activity could be distinguished in terms of disease manifestations and multimeric patterns of plasma von Willebrand factor (VWF). ADAMTS13 activity, VWF antigen, and multimeric pattern were evaluated in patients with recurrent and familial TTP (n = 20) and HUS (n = 29). Results of the collagen-binding assay of ADAMTS13 activity were confirmed in selected samples by testing the capacity of plasma to cleave recombinant VWF A1-A2-A3. Most patients with TTP had complete or partial deficiency of ADAMTS13 activity during the acute phase, and in some the defect persisted at remission. However, complete ADAMTS13 deficiency was also found in 5 of 9 patients with HUS during the acute phase and in 5 patients during remission. HUS patients with ADAMTS13 deficiency could not be distinguished clinically from those with normal ADAMTS13. In a subgroup of patients with TTP or HUS, the ADAMTS13 defect was inherited, as documented by half-normal levels of ADAMTS13 in their asymptomatic parents, consistent with the heterozygous carrier state. In patients with TTP and HUS there was indirect evidence of increased VWF fragmentation, and this occurred also in patients with ADAMTS13 deficiency. In conclusion, deficient ADAMTS13 activity does not distinguish TTP from HUS, at least in the recurrent and familial forms, and it is not the only determinant of VWF abnormalities in these conditions.

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