TTP: Diagnosis, Clinical Management, and the Role of Therapeutic Plasma Exchange

1
TTP Diagnosis, Clinical Management, and the Role
of Therapeutic Plasma Exchange

• Nick Bandarenko III, M.D.
• Associate Professor
• Pathology and Laboratory Medicine
• UNIVERSITY OF NORTH CAROLINA

2
Bandarenko Objectives

• Understand how TTP is recognized, the
  differential diagnostic considerations and, the
  role of therapeutic plasma exchange (TPE).
• Define clinical challenges in the management of
  TTP patients specifically diagnosis, patterns of
  response, clinical endpoints / outcomes, and
  adverse reactions.
• Understand the role of ADAMTS13 in normal
  physiology, methods for measurement, and
  implications for guiding patient management.

3
Bandarenko TTP Clinical diagnosis of exclusion

• No diagnostic test!
• Systemic process with hematologic abnormalities

4
Bandarenko TTP Clinical diagnosis of exclusion

• PENTAD for recognition
• microangiopathic hemolytic anemia
• thrombocytopenia
• renal failure
• mental status changes
• Fever
• Rule out other explainable causes

5
Bandarenko TTP Clinical diagnosis of exclusion

• Microangiopathic Hemolytic Anemia MAHA
• Mechanical RBC destruction
• Evidence Schistocytes in peripheral blood

6
Bandarenko TTP Clinical diagnosis of exclusion

• Diverse Causes of Thrombotic Microangiopathy
  (TMA)
• TTP
• Severe hypertension (systolic BP 200)
• DIC, sepsis
• HELLP syndrome (preclampsia)
• Metastatic adenocarcinoma
• HIV
• Intravascular prosthetic devices e.g. LV assist
  device

7
Bandarenko TTP Clinical diagnosis of exclusion
TTP
HTN
DIC
Can all have overlapping and similar clinical
presentations
8
Bandarenko TTP Clinical diagnosis of exclusion

• Supporting Laboratory Studies
• RESULT
• CBC with smear
• LDH lactate dehydrogenase ???
• Coagulation studies nl
• DAT direct Coombs' test neg
• Haptoglobin ?
• Bilibrubin (unconjugated) ?
• Creatinine, BUN /-?
• Will there be a direct diagnostic test?
• ADAMTS13?

9
Bandarenko TTP Recent Diagnostic Considerations
10
Bandarenko TTP Recent Diagnostic Considerations

• Case Study
• 50 yo male admitted to ICU with
• Headache, blurred vision, dizziness
• Hgb 7.1 g/dL, Plt count 39, Schistocytes
• LDH 2800 U/L, Creatinine 8.3
• Afebrile
• Normal coagulation studies,
• Negative DAT
• BP214/133 mmHg.

11
Bandarenko TTP Recent Diagnostic Considerations

• He has 4 of 5 findings in TTP pentad
• Mental Status Changes
• Anemia with schistocytes (MAHA)
• Thrombocytopenia
• Renal failure
• No fever
• Ruled out DIC, Immune RBC injury
• Severe HTN present, BP200/100

12
Bandarenko TTP Clinical diagnosis of exclusion

• Clinical Course with HTN control and NO TPE

13
Bandarenko TTP Recent Diagnostic Considerations

• Severe Hypertension may present with clinical
  picture of TTP
• Papilledema (malignant HTN) not required
• Management of HTN aggressively
• TPE may not be indicated
• Potential role for ADAMTS13 to help?

14
Bandarenko TTP Clinical Settings are Diverse

• Primary or Idiopathic
• Secondary causes of TTP
• Connective Tissue Disease (SLE)
• Drugs quinine, ticlopidine, clopidogrel
• Hormonal changes (menses, pregnancy, OCP's)
• Occult Infection
• Chemotherapy cis platinum, mitomycin c
• Bone Marrow Transplant
• HIV
• Is the pathogenesis the same for all?
• Potential role for ADAMTS13 measurement?

15
Bandarenko TTP TMA after HPSCT (BMT associated
TTP)

• TPE no longer recommended as standard of care for
  TMA after HPSCT
• Ho VT, Cutler C, Carter S, et al. Blood and
  marrow transplant clinical trials network
  toxicity committee consensus summary thrombotic
  microangiopathy after hematopoietic stem cell
  transplantation Biol Blood Marrow Transplant.
  2005 Aug11(8)571-5.
• Severe deficiency of ADAMTS13 not seen in this
  setting
• Elliott MA, Nichols WL Jr, Plumhoff EA , et al.
  Posttransplantation thrombotic thrombocytopenic
  purpura a single-center experience and a
  contemporary review.Mayo Clin Proc. 2003
  Apr78(4)421-30.

16
Bandarenko TTP Role of TPE

• TPE is life-saving therapy
• ASFA Category I
• Mortality reduced from near 100 to 90
• Most patients will survive acute episode
• Still, a devastating illness with significant
  risk of death

17
Bandarenko TTP Role of TPE

• Emergent plasma exchange (TPE)
• 1 PV -1.5 PV
• increasing PV exchanged may be used in refractory
  patients or those severely affected
• Plasma is replacement of choice
• DAILY TPE
• Watch out for anemia (may need RBCs)
• FFP infusions if TPE delayed

18
Bandarenko TTP Role of TPE

• Response Defined clinically
• Hematologic recovery
• Renal dysfunction may persist and require long
  term dialysis (HUS)
• No fever or mental status changes
• Response time number of days to clinical recovery

19
Bandarenko TTP Role of TPE

• Hematologic Recovery
• THERAPEUTIC GOALS FOR TPE
• AABB platelet count 150 x 109 /L normal
  serum LDH and,
• ASFA platelet count 100 x 109/L normal
  LDH
• on 2 consecutive days

20
Bandarenko TTP Time to Response
J of Clin Apheresis 13133-141, 1998. United
States Thrombotic Thrombocytopenic Purpura
Diagnosis Study Group (US TTP ASG) Multicenter
Survey and Retrospective Analysis of Current
Efficacy of Therapeutic Plasma Exchange
21
Bandarenko TTP Role of TPE

• Durability of Response is determined once TPE is
  stopped
• Tincture of time
• Frequent early relapses (exacerbations within 2-4
  weeks of response) suggest pathophysiologic
  abnormalities may persist.
• No lab test yet to determine if underlying
  pathophysiology is resolved
• Is there still subclinical disease?

22
Bandarenko TTP Role of TPE

• Prognostic Indicators of Response/ Relapse
• PARAMETERS WHICH HAVE NO EFFECT
• platelet count and LDH at presentation
• plasma volume
• Replacement fluid type
• Potential Role for ADAMTS13 measurement?

23
Bandarenko TTP Patterns of Response A closer
look at differences among TTP patients
24
Bandarenko TTP Patterns of Response to TPE

• Response is not necessarily a linear improvement
• Patient recovery may follow different patterns
• Platelet count may decline during serial daily
  TPE
• Concerns of refractoriness may arise

25
Bandarenko TTP Patterns of Response to TPE
Hay S, Egan JA, Millward PA, et al. Patterns of
Platelet Response in Idiopathic TTP/HUS.
Therapeutic Apheresis and Dialysis. 2006
10(3)236-240. n60
26
Bandarenko TTP Patterns of Response to TPE

• Is ADAMTS13 function or other biomarker
  predictive of pattern of response?
• Serial measurement
• Do some patients form inhibitors to ADAMTS13
  after presentation and initiation of TPE?
• Exacerbations, treatment rollercoasters
• Further study needed

27
CURRENT CLINCIAL OUTCOMES

• 60-65 complete remission
• 35-40 relapse rate
• Early relapse (exacerbation)-days to weeks
• Late recurrence- months to years later
• No diagnostic test to predict relapse
• No prognostic indicator currently to predict
  relapse
• Will ADAMTS13 measurement be useful?

28
Bandarenko TTP Patient Management
29
Bandarenko TTP Patient Management

• TPE is an invasive procedure with risks
• Frequency of Adverse Reactions (7.8 -35)
• Citrate toxicity
• Transfusion Reactions- plasma
• Vascular access complications
• Other
• McLeod, BC, et al.Frequency of immediate
  adverse effects associated with therapeutic
  Diagnosis.1999.Transfusion 39 (3), 282-288.Brig
  gs D, et al. Complications of Therapeutic
  PlasmDiagnosis review of 1727 procedures. J of
  Clin Apheresis 2006216 (abstract 13)

30
Bandarenko TTP Citrate

• ACD anticoagulation for apheresis plus citrate in
  the plasma replacement.
• Higher incidence of citrate related symptoms
• Paresthesias
• N V
• Hypotension
• Flatus
• EKG changes

31
Bandarenko TTP Allergic Reactions

• Urticaria/hives are commonly seen in TTP patients
  
• frequency of 55-76
• tend to occur after 30 to 35 donor exposures
• or 9 to 10 liters of plasma
• Typical Rx course
• Plasma volume 3 liters x 8 days24 liters, or
  about 72 donor exposures
• Reutter JC, Sanders K, et al. Incidence of
  Allergic Reactions with Fresh Frozen Plasma or
  Cryo-supernatant Plasma in the Treatment of
  Thrombotic Thrombocytopenic Purpura. Journal of
  Clinical Apheresis 2001 16(3)134-138.

32
Bandarenko TTP Patient Management

• TPE is an invasive procedure with risks
• Carefully assess risks and benefits before TPE
  and throughout treatment
• Can ADAMTS13 help refine this determination?

33
Bandarenko TTP Adjuncts to TPE

• Management of Refractory patients and Chronic
  relapses
• Assess for underlying cause
• Connective disease, Malignancy
• Occult infection (trial of empiric ABx)
• Hypertension
• Medications
• Hormonal changes
• Increase plasma volume
• Adjuncts
• PHARMACOLOGIC (vincristine, rituximab)
• SPLENECTOMY

34
Bandarenko TTP Adjuncts to TPE

• Adjunct therapies are also applied variably
• No standard protocol or agreement
• Confound interpretation of literature and
  hinders multicenter studies
• Steroids dosage typically 1mg/kg/day
• Anti-platelet drugs
• Other
• Vincristine
• Splenectomy
• Rituximab

35
Bandarenko TTP Adjuncts to TPE Rituximab

• Monoclonal antibody against CD20 on B lymphocytes
• Non-Hodgkins Lymphoma
• Autoimmune disease
• In TTP, presence of inhibitory antibody to
  ADAMTS13
• Possible autoimmune pathogenesis
• Abnormal B cell clonal proliferation may be
  involved in subsets of TTP patients

36
Bandarenko TTP Reported Cases of Rituximab Use
From Millward, P.M., Bandarenko, N., Chang,
P.P., et al.Cardiogenic shock complicates
successful treatment of refractory TTP with
rituximab. Transfusion 45 (9), 1481-1486.
37
Bandarenko TTP Case Report Rituximab
From Millward, P.M., Bandarenko, N., Chang,
P.P., et al.Cardiogenic shock complicates
successful treatment of refractory TTP with
rituximab. Transfusion 45 (9), 1481-1486.
38
Bandarenko TTP Adjuncts to TPE Rituximab
Millward, P.M., Bandarenko, N., Chang, P.P., et
al.Cardiogenic shock complicates successful
treatment of refractory TTP with rituximab.
Transfusion 45 (9), 1481-1486.
WARNINGS Fatal Infusion Reactions Deaths within
24 hours of RITUXAN infusion have been reported.
These fatal reactions followed an infusion
reaction complex which included hypoxia,
pulmonary infiltrates, acute respiratory distress
syndrome, myocardial infarction, ventricular
fibrillation or cardiogenic shock. Approximately
80 of fatal infusion reactions occurred in
association with the first infusion. (See
WARNINGS and ADVERSE REACTIONS.) Patients who
develop severe infusion reactions should have
RITUXAN infusion discontinued and receive medical
treatment. Tumor Lysis Syndrome (TLS) Acute
renal failure requiring dialysis with instances
of fatal outcome has been reported in the setting
of TLS following treatment with RITUXAN. (See
WARNINGS.) Severe Mucocutaneous Reactions
Severe mucocutaneous reactions, some with fatal
outcome, have been reported in association with
RITUXAN treatment. (See WARNINGS and ADVERSE
REACTIONS.)
39
Bandarenko TTP Role of TPE

• Multicenter studies
• SERF TTP Northwestern University
• NIH funded multicenter study
• Epidemiology, risk factors (medications), and
  pathophysiology
• NIH Transfusion Medicine/ Hemostasis Clinical
  Research Network
• 17 Academic Centers with a clinical coordinating
  center
• TTP clinical trial in planning

40
Bandarenko TTP Potential Role for ADAMTS13

• NEED a Pathophysiologic marker of TTP activity
• Narrow differential Dx at presentation
• Detect subclinical disease at time of hematologic
  recovery
• Predict relapse, prolonged TPE
• Better define Risk Benefit ratio

41
ADAMTS13 the panacea we are looking for?
42
Bandarenko TTP Role of TPE

• END

43
ADAMTS13 Description, Measurement, Clinical
Implications in TTP

• Kenneth Friedman, M.D.
• Medical Director
• Hemostasis Reference Laboratory
• BloodCenter of Wisconsin
• ASFA - April 2007

44
K. Friedman Unusually large multimers of VWF are
present in plasma of patients with TTP
Moake JL J Thromb Haemostas 200421515-1521

• 1982 Joel Moake postulated a missing
  depolymerase results in circulating UL-VWF
  multimers
• ? platelet clump formation
• ? obstruction of the microcirculation
• ? clinical TTP

45
K. Friedman Milestones Identification of VWF
cleaving protease

• 1996 Tsai and Furlan independently described a
  plasma protease that cleaves normal VWF
• 1997-8 Furlan described 4 patients with
  relapsing TTP who lacked VWF-cleaving protease
• A TTP case with IgG antibody-inhibitor of VWF-CP
  was noted
• 1998 Two large retrospective series demonstrate
  that a majority of TTP patients have VWF-CP
  deficiency (and Ab)
• Furlan, M. et al. N Engl J Med 19983391578-1584
• Tsai, H.-M. et al. N Engl J Med
  19983391585-1594

46
K. Friedman VWF cleaving protease in TTPStudy
findings of Furlan et al, Tsai and Lian, 1998
Tsai, H.-M. et al.N Engl J Med 19983391585-1594

• VWF-CP is deficiency in congenital TTP
• VWF-CP is generally very low in acquired
  idiopathic TTP, inhibitor antibody can be
  demonstrated
• VWF-CP levels often come up with TPE-based
  treatment
• VWF-CP is normal in HUS and several other
  thrombocytopenic disorders

47
K. Friedman VWF cleaving protease is ADAMTS13 A
Disintegrin-like And Metalloprotease with
ThromboSpondin type 1 motifs, 13

• Identification of VWF-CP in 2001
• Characteristics
• Plasma protein derived mainly from hepatic
  stellate cells
• and also endothelium and megakaryocytes
• Only known physiologic substrate is VWF
• Shear forces allow ADAMTS13 access to A2 domain
  of VWF

Lämmle B, et al J Thromb Haemostas 2005 3
1663-1675
48
K. Friedman Without ADAMTS13, unwanted
platelet/VWF thrombi form
Dong J-F J Thromb Haemostas 200531710-1716
49
K. Friedman Platelets will decorate released
VWF, but ADAMTS13 prevents decorated strings
Moake JL J Thromb Haemostas 200421515-1521
50
BandarenkoADAMTS13 the panacea we are looking
for?
51
K. Friedman ADAMTS13 provides some answers in
TTP

• Provides a plausible mechanism of TTP
  pathogenesis
• Absent ADAMTS13 ? platelet/VWF thrombi
• Provides a rational for efficacy of TPE
• TPE depletes auto-antibody to ADAMTS13
• Plasma infused during TPE replaces ADAMTS13
• Explains why immune-modulation works
• But
• Does it provide all Dr. Bandarenko wants?

52
Dr. Bandarenko asks

• Does ADAMTS13 explain it all?
• Is there just one pathogenesis for all thrombotic
  microangiopathies?
• Is a lab assay of ADAMTS13 clinically useful?
• Is ADAMTS13 level a direct diagnostic test for
  TTP?
• Would ADAMTS13 level be useful when the diagnosis
  is unclear?
• Will ADAMTS13 be prognostic of course in TTP?
• Is ADAMTS13 a biomarker of disease activity
• Does it explain treatment rollercoasters
• Can ADAMTS13 measurement be used to chart course
  of TPE?
• Will ADAMTS13 testing predict who will relapse
  and when?

53
K. Friedman Assays of ADAMTS13 activity

• Activity assays
• Based on degradation of VWF (or a VWF fragment)
• Step 1 Proteolysis of substrate by ADAMTS13
• Step 2 Substrate digestion is quantified
• Disappearance of intact VWF by gel-based assay
• Decrease of a VWF functional capacity (CBA
  method)
• or
• Accumulation of a proteolysed degradation product
  (FRET)
• Level of detection is 5 of Normal
• Inhibitor assay
• Done via mixing study (similar to a coagulation
  factor inhibitor assay)

54
K. Friedman Fluorogenic resonance energy
transfer FRETS-VWF73 Assay
.

• Without ADAMTS13 cleavage, light emitted by Nma
  is absorbed by Dnp-quencher
• Fluorescence is not detected

Kokame, et alBritish Journal of Haematology
2005129 (1), 93-100.
55
K. Friedman Fluorogenic resonance energy
transfer FRETS-VWF73 Assay

• ADAMTS13 cleavage of Tyr-Met bond separates
  Dnp-quencher from Nma emitter
• Fluorescence is detected
• Assay occurs in real time over 60 min, allowing
  rapid turn-around
• Limit of detection 5 of normal

Kokame, et alBritish Journal of Haematology
2005129 (1), 93-100.
56
K. Friedman FRETS-VWF73 performanceis
comparable to CBA method
FRET Peptide Assay result (BU)
FRET Peptide Assay result ()
Collagen Binding Assay result ()
Collagen Binding Assay result (BU)
Data from BloodCenter of Wisconsin

• Activity by FRETS-VWF73 and CBA-based correlate
  well, and assay turn-around time improved with
  FRET method
• Inhibitor results are comparable

57
K. Friedman ADAMTS13 antibody assay

• Qualitative immunoblot-based indicate
• Most inhibitor patients have multiple antibody
  specificities, but antibody to Cysteine-rich/Space
  r domains is very common
• There are some patients with non-inhibitory
  antibody (which may promote ADAMTS13 clearance).
• ELISA assays are emerging for anti-ADAMTS13
• In patients with ADAMTS13 activity vast majority had IgG antibody (Reiger M, et al
  Blood 2005)

58
K. Friedman ADAMTS13 assay performanceSensitivi
ty, Specificity, Limitations

• Utility for early decision making in TTP
• ADAMTS13 activity assays generally only been
  available from specialty labs
• Long turnaround time ? TPE decision made before
  result back
• Utility of a diagnostic test depends on its
  clinical performance characteristics
• Sensitivity and specificity remain controversial
  
• No gold standard criteria for a diagnosis of
  TTP
• Difficult to distinguish TTP from HUS and other
  forms of TMA

59
K. Friedman Proportion of patients with
severely deficient ADAMTS-13 activity (usu

Author Design of study Severely
deficient/total ()

Vesely et al. 2003 Inception cohort, single
center 16/48 33

Peyvandi et al. 2004 Multicenter 48/100 48

Matsumoto et al. 2004 Multicenter 56/108 52

Kremer Hovinga. 2004 Multicenter 56/93 60

Mori et al. 2002 Retrospective? 12/18 66

Veyradier et al. 2001 Prospective,
multicenter 47/66 71

Zheng et al. 2004 Single center,
prospective 16/20 80

Furlan et al. 1998 Retrospective,
multicenter 26/30 86

Groot et al. 2006 Prospective 24/27 89

Tsai and Lian 1998 Retrospective 37/37 100

Series collated by Lämmle B, et al J Thromb
Haemostas 200531663-1675
60
K. Friedman Severe ADAMTS13 deficiency is rare
in secondary TTP

• Cancer
• Hematopoietic stem cell transplantation
• Solid organ transplantation
• Preeclampsia
• Systemic infection
• Diarrhea associated HUS

Sorry Nick, ADAMTS13 does not explain it all
61
K. Friedman Specificity Other diseases where
low ADAMTS13 activity was observed

• Mild deficiency of ADAMTS13 is common
• Uremia, chronic inflammation, pregnancy,
  post-operatively, liver disease
• Mannucci PM, et al Blood 2001
• Severe deficiency
• Liver disease (Mannucci PM, et al Blood 2001)
• Sepsis-induced DIC (Oto T, et al 2006)
• 17 of 109 patients had ADAMTS13 109 had ADAMTS13
• Disseminated Malignancy (Oleksowicz et al 1999)
• Mean ADAMTS13 was 4.9 in 10 patients with
  metastatic disease
• Severe hemolysis in sample (Studt JD, et al
  Blood 2005)
• Free hemoglobin inhibits ADAMTS13

62
K. Friedman Experience with FRETS-VWF73

• Prospective study 79 patients with Coombs
  negative hemolytic anemia and thrombocytopenia

Sensitivity 89 Specificity 98
Groot E, et al J Thromb Haemostas
200641538-1675
63
K. Friedman Value of ADAMTS13 activity in
idiopathic TTP at presentation

• Diagnostic value of ADAMTS13
• It is not always severely deficient in idiopathic
  TTP
• Cant use assay result to deny TPE therapy!
• Prognostic value in idiopathic TTP
• Severe ADAMTS13 deficiency associations
• Vesele S, et al Blood 2003, Raife T, et al
  Transfusion 2004, Zheng XL, et al Blood 2004
• High titer inhibitor associated with poorer
  outcome
• A relapsing course was more common
• Unclear if ADAMTS13 level correlates with number
  of TPE required (OK-no, WI-yes)
• In idiopathic TTP, clinical recovery may occur
  despite persistently low ADAMTS13

64
K. Friedman Value of ADAMTS13 activity in
secondary TTP at presentation

• Non-idiopathic TTP associations
• Vesele S, et al Blood 2003, Raife T, et al
  Transfusion 2004, Zheng XL, et al Blood 2004
• Severe ADAMTS13 deficiency is rare
• Mortality rare is high

65
K. Friedman Value of ADAMTS13 testing in
overlap syndromes

• Autoimmune Thrombotic Microangiopathy
• Systemic Lupus Erythematosis
• Severe deficiency of ADAMTS13 may indicate a role
  for apheresis
• Pregnancy
• ADAMTS13 expected to be adeqate in HELLP and
  preeclampsia
• Severe ADAMTS13 deficiency may indicate TTP
  complicating pregnancy

66
K. Friedman ADAMTS13 replacement destroys
unwanted platelet thrombi
Furlan M J Thromb Haemostas 200421505-1509
67
K. Friedman Replacement fluids for TPEMean
ADAMTS13 activity
Normal (20) 12524
Scott EA, et al Transfusion 200747120-125
68
K. Friedman ADAMTS13 as a biomarker

• The relationship between ADAMTS13 activity and
  clinical situation is imprecise
• In acquired TTP, clinical recovery may occur
  despite persistently low ADAMTS13
• But
• nearly all patients with relapsing TTP have
  severe deficiency of ADAMTS13 at the time of
  relapse.
• Should the goal of therapy be suppression of
  autoantibody and restoration of ADAMTS13 level?

69
Ken Friedman addresses Dr. Bandarenkos Questions

• Does ADAMTS13 explain it all? NO
• Is lab assay of ADAMTS13 clinically useful? YES
• A very low level (with inhibitor or Ab) supports
  a dx of TTP
• A low level may argue for a trial of TPE in
  cross-over syndromes
• But a detectable level does not exclude TTP
• Is ADAMTS13 level a marker for disease activity?
  Maybe
• Low level of activity appears to be only a risk
  factor for clinical disease
• ADAMTS13 level should not drive TPE schedule at
  current time
• Is ADAMTS13 prognostic of disease course in TTP?
  YES
• Low level activity at presentation is a risk
  factor for relapse
• Much is yet to be learned from further clinical
  studies

70
K. Friedman

• END