THROMBOTISCHE MIKROANGIOPATHIE – PATHOPHYSIOLOGIE-BASIERTE
THERAPIEOPTIONEN
Paul KNÖBL Medizinische Universität Wien
Klinik für Innere Medizin 1, Abteilung für Hämatologie und Hämostaseologie Allgemeines Krankenhaus der Stadt Wien
TMA: Leitsymptome
• Coombs-‐nega,ve, hämoly'sche Anämie mit Erythrozytenfragmen,erung
• Thrombozytopenie durch verstärkte Plä?chenaggrega,on und –verbrauch
• Störung der Mikrozirkula,on durch plä?chenreiche Mikrothromben
• Diffuse Organfunk'ons-‐ störung (Gehirn, Niere, Herz, Lunge, Darm, etc.)
Klassifikation der TMA (i) Art der TMA Pathophysiologie
Thrombotisch-thrombopenische Purpura (TTP) Schwerer ADAMTS13-Mangel
Kongenitale TTP (Upshaw-Schulman Syndrom) ADAMTS13-Genmutationen
Erworbene TTP (M.Moschcowitz) Anti-ADAMTS13 Antikörper
Hämolytisch-urämisches Syndrom (HUS)
Kongenitales HUS Komplementsystem-Genmutationen
Erworbenes HUS Autoantikörper gegen
Komplementbestandteile Unbekannte Ursachen
Diarrhoe-/Shigatoxin-assoziiertes HUS Toxine
Knöbl, Hämostaseologie 2013
Klassifikation der TMA (ii) Art der TMA Pathophysiologie
Sekundäre TMA
Infektionen Medikamente Organtransplantationen
unbekannt. Endothelzell-Schädigung
Andere TMA-Formen
Schwangerschafts-assoziiert: HELLP EPH-Gestose
unbekannt
Systemerkrankungen System.Lupus erythematodes Antiphospholipid-Antikörper Syndrom Vaskulitis Maligne Hypertension
unbekannt
Knochenmarks-Karzinose Infiltration mit malignen Zellen
Eli Moschcowitz, Arch Intern Med 1925; 36: 89–93 Reprint in: Mt Sinai J Med. 2003 Oct;70(5):352-5
TTP: Erstbeschreibung
Endothelzelle
von Willebrand Factor
UL VWF Mul'mere
ADAMTS13
normales VWF Mul'merenmuster
bei stark verminderter ADAMTS13-‐ Ak,vität:
(kongenitaler Mangel oder Autoan'körper)
=> UL-‐VWF MM persis,eren
spontane Plä?chenaggrega,on in Situa,onen mit erhöhten Blut-‐
scherkräXen
Thrombozyten-‐ aggrega'on
TTP: Pathogenese
Häufigkeit: 1,0 -‐ 1,5 Fälle / 100.000 Kinder und Jugendliche unter 16 Jahre OX Kinder und Jugendliche zwischen 1 und 5 Jahren Klinik: TMA-‐typische Laborkonstella,on Nierenversagen steht im Vordergrund aber häufig auch andere Organschäden Diagnos'k: Manchmal Veränderungen im Komplementsystem OX keine spezifischen Abnormalitäten feststellbar; klinische Diagnose.
Hämolytisch-urämisches Syndrom (HUS):
Diarrhoe-‐assoziiertes HUS: Enterohämorrhagische Infek'onen:
Shiga-‐ oder Verotoxin bildende Keime: EHEC: E.Coli, v.a. Serotyp O157:H7, Shigella
Outbreaks Keine spezifische Diagnos,k verfügbar.
Hämolytisch-urämisches Syndrom (HUS):
„atypisches“ HUS: ohne Diarrhoe
Ursachen: Medikamente, Transplanta,onen, Infek,onen, manchmal spontan
Manchmal (-‐50%) assoziiert mit Veränderungen im Komplementsystem: • zahlreiche Muta'onen/Polymorphismen bekannt: (Faktor H, Faktor H related Protein
1 , Faktor I, MCP (CD46), Faktor B und Thrombomodulin, C3) führen zu einer verstärkten Ak,vierung des Komplementsystems (alterna,ver Weg) und nachfolgender Zellschädigung.
= familiäres / kongenitales / hereditäres / chronisch relapsierendes HUS
• Autoan'körper gegen Faktor H (oder andere Komplementbestandteile), meist in Kombina,on mit einer Muta,on des Faktor H related Protein 1 und 3
=erworbenes / sporadisches HUS
Trotz Therapie hohe Rate von terminalem Nierenversagen und anderen chron. Organschäden
Hämolytisch-urämisches Syndrom (HUS):
Diagnostik bei TMA (i)
Ziel Methoden
Hämolyse Hämoglobin, Erythrozytenzahl, Indizes, Retikulozyten, Fragmentozyten
LDH, Haptoglobin, freies Hämoglobin, Bilirubin Coombs Test
Thrombopenie Thrombozytenzahl, Immature platelet fraction
Anamnese Frühere und andere Erkrankungen, auslösende Ursachen (Tumore,
Infektionen, Systemerkrankungen, Transplantation, Schwangerschaft, Medikamente, Chirurgie, etc.), Familienanamnese
Knöbl, Hämostaseologie 2013
Diagnostik bei TMA (ii)
Ziel Methoden
Erfassung von Organschäden
Gehirn Zerebrale CT, Perfusions-MRT, EEG, S100 beta, NSE neurokognitive Testung
Nieren Serum-Kreatinin, glomeruläre Filtrationsrate, Harnmengen
Herz EKG, Troponin, NT-proBNP, Echokardiographie
Lunge Sauerstoff-Sättigung, Gasaustausch, Lungenröntgen, HR-CT
Blutgerinnung Gerinnungstests, Antiphospholipid-Antikörper
Pankreas Glukose, Serum Amylase und Lipase
Diagnostik bei TMA (iii)
Ziel Methoden
Spezifische Diagnostik:
Generell: Biobank, Proben für event. Studien
Blutgruppe, Schwangerschaftstest, Virologie (HIV, Hepatitis B and C) Harnanalysen, Schilddrüsenfunktion
TTP: ADAMTS13-Aktivität, -Antigen, Anti-ADAMTS13 Antikörper und –inhibitor
ADAMTS13 Genanalyse VWF:Ag, -RiCo, -CBA, -Multimerenkomposition,
HUS: Bakteriologie, Toxin-Nachweis (E.Coli, shigella, etc.)
Komplement C3, C4, CH50, Terminales Komplement Komplement-Faktor-Genanalysen
Etablierte Therapieoptionen bei TMA Therapie Indikation Mechanismus
Plasma-Austausch Initiale Therapie bei allen Formen der TMA
Elimination von Autoantikörpern, Immunkomplexen,
UL-VWF MM, Sludge Zufuhr von
ADAMTS13 u.normalem VWF
Plasma-Infusion Kongenitaler Mangel (ADAMTS13, Komplement,…)
Zufuhr von ADAMTS13, Komplement,…
Corticosteroide Autoantikörper (ADAMTS13, Komplement,…) Immunsuppression
Rituximab Autoantikörper (ADAMTS13, Komplement,…) Immunsuppression
Splenektomie Refraktäre TTP Elimination von Memory- und T-Zellen?
Supportive Therapie Erythrozytentransfusion,
Intensivstation Nierenersatztherapie
Knöbl, Hämostaseologie 2013
Humanisierter Maus Antikörper gegen CD20
Zerstörung von B-Zellen
Etabliert für CD20-pos. maligne Lymphome
Etabliert für verschiedene Autoimmunerkrankungen
Hoch effiziente Autoantikörper-Elimination bei TTP
95 % komplette Remissionen innerhalb von 1-3 Wochen
STAR Trial terminiert (langsames Enrollment), zur Zeit keine anderen
kontrollierten klinischen Studien
Knöbl et al, 2008; Froissard et al, 2012; Scully et al, 2011
Rituximab bei TTP
Alternative Therapieoptionen bei TMA
Therapie Indikation Mechanismus
Immunomodulatoren (Vincristin, MMF, Cyclosporin, Cyclophosphamid)
Autoantikörper (ADAMTS13, Komplement,…) Immunsuppression
Anti-Plättchen Medikamente (ASS, Clopidogrel, Prasugrel, Ticagrelor)
TMA mit schweren Mikrozirkulationsstörungen
Hemmung der Plättchenaggregation
Experimentelle Therapieoptionen Therapie Indikation Mechanismus
Rekombinantes ADAMTS13
Kongenitaler ADAMTS13 Mangel Zufuhr von ADAMTS13
Rekombinantes ADAMTS13 Autoimmun-TTP ? Zufuhr von ADAMTS13 zur
Neutralisierung der Antikörper
Caplacizumab Akute TTP-Schübe Blockade der VWF A1 Domänen, Kompetition mit GP Ib/IX
ARC1779 Akute TTP-Schübe Blockade der VWF A1 Domänen, Kompetition mit GP Ib/IX
ARC 15105 Akute TTP-Schübe ? Chronische TTP ?
Blockade der VWF A1 Domänen, Kompetition mit GP Ib/IX
Eculizumab aHUS Blockade des Komplementsystems
N-Acetylcystein TTP ? Spaltung der Disulfidbrücken im VWF
• Verfügbar als Diagnostikum (z.B. anti-ADAMTS13 antibody ELISA)
• In Entwicklung als Therapeutikum (Baxter AG, Austria)
• Erste klinische Studien (Phase I)
• Sehr hilfreich bei kongenitaler TTP –
prophylaktische Behandulng mit 20-40 U/kg alle 2-4 Wochen
- Risiko der Allo-Antikörper Entwicklung
• Unklare Wirksamkeit bei hochtitrigen
Autoantikörpern.
Interessante in vitro Versuche zur
Errechnung der notwendigen Dosis
zum Überkommen der Antikörper.
Plaimauer et al, 2011
Rekombinantes ADAMTS13
Scherkräfte
ADAMTS13 X X X X X X
Anti – GP Ib Substanzen:
• VCL Peptid • Spezifische Proteasen gegen GPIbα: • bakt. O-Sialylglycopeptid-Endopeptidase • Metalloproteasen aus Schlangengiften • Antikörper, Fab Fragmente, or Nanobodies • GPIb-bindende C-Typ Lektine aus Schlangengiften • Thrombin-Mutanten • Aurin-Tricarboxyl-Säure • “small molecules”, zyklische Peptide
Platelet GPIb complex as a target for anti-thrombotic drug development. Kenneth J. Clemetson, Jeannine M. Clemetson. Thromb Haemost 2008; 99: 473–479
Blockade der GP Ib – VWF Interaktion
Scherkräfte
ADAMTS13 X X X X X X
Anti – VWF A1 Substanzen:
• ARC 1779 Aptamer
• ARC 15105 Aptamer
• ALX 0081 Nanobody (=Caplacizumab)
• AJW200 Antikörper
• rGPG 290
Blockade der GP Ib – VWF Interaktion
• 40-Nukleotid DNA/RNA Aptamer
gekoppelt an 20 kDa PEG
• Selektiert auf hochaffine Bindung an VWF
A1 Domänen
• Potenter und selektiver kompetitiver
Antagonist der vWF A1 Bindung an
Thrombozyten-GP Ib (Kd ≈ 2 nM)
• Sterile Lösung für iv. Injektion bzw.
kontinuierliche Infusion
ARC 1779
0
20
30
40
50
60
70
80
90
100
29 36 43 50 57 64
platelets
10
1
10
100
ARC1
779 level
days from start of plasma exchange
(/nL)
(µg/ml)
ARC1
779
infusion
rate
2.0 3.0
bolus
(µg/kg/min) Anti-von Willebrand factor aptamer ARC1779 for refractory thrombotic
thrombocytopenic purpura.
Knöbl P, Jilma B, Gilbert JC, Hutabarat RM, Wagner PG, Jilma-Stohlawetz P.
Transfusion. 2009 Oct;49(10):2181-5.
Männlicher Patient mir refraktärer Autoimmun-TTP St.p. 30x PEX, Splenektomie, Steroide Schwere neurologische und kardiale Beeinträchtigung
Phase 2b randomisierte, multizentrische, doppelblinde
Dosisfindungsstudie bei akuter TMA (NCT00726544)
Vom Sponsor nach Einschluß von 9 Patienten beendet
Statistical analysis. Categorical variables were summarized using fre-
quency counts and percentages. Continuous variables were summarized
using one or more of the following: mean, standard deviation, median, mini-
mum, and maximum, 75th and 90th percentile, ignoring missing data when
applicable. Age at survey, age at start of chronic transfusion therapy, aver-
age weight, average pretransfusion Hb and %HbS, average transfusion vol-
ume, duration of transfusion therapy and predominant transfusion type were
summarized with each patient contributing equally. Weight, pretransfusion
Hb and %HbS, transfusion volume, and days late were also summarized
with each transfusion contributing equally. The probability of pretransfusion
%HbS less than 30% was modeled using generalized estimating equations
to account for the lack of independence induced by multiple transfusions per
subject. The models were used to generate estimates of the odds ratio (OR)
and 95% confidence intervals. Results were considered statistically signifi-
cant if the confidence interval excluded one.
AcknowledgmentsThe authors thank the entire TWiTCH Trial Group (members listed in
‘‘Appendix’’) and Rho Federal Systems Division, Inc. (Nancy Yovetich PhD,
Christopher Woods, Jamie Spencer, Marsha McMurray) for their valuable
contributions to the study.
1St. Jude Children’s Research Hospital, Memphis, Tennessee; 2Rho Inc., ChapelHill, NC; 3Baylor College of Medicine, Houston, Tennessee; 4Emory University/Children’s Healthcare of Atlanta, Atlanta, Georgia; 5Children’s National Medical
Center, Washington, DC; 6Medical University of South Carolina, Charleston, SouthCarolina; 7University of Mississippi Medical Center, Jackson, Mississippi;
8University of Texas Southwestern Medical Center at Dallas, Dallas, TX; 9WayneState University, Detroit, Michigan; 10Children’s Memorial Hospital, Chicago,
Illinois; 11Nemours Children’s Clinic, Jacksonville, Florida*Correspondence to: Banu Aygun, MD, St. Jude Children’s Research Hospital,Department of Hematology, M/S 800, 262 Danny Thomas Place, Memphis, TN
38105-3678E-mail: [email protected]
Conflict of interest: Nothing to report.
Published online 29 December 2011 in Wiley Online Library(wileyonlinelibrary.com).DOI: 10.1002/ajh.23105
References
1. Adams RJ, McKie VC, Hsu L, et al. Prevention of a first stroke by transfu-sions in children with sickle cell anemia and abnormal results on transcranialDoppler ultrasonography. N Engl J Med 1998;339:5–11.
2. Ohene-Frempong K, Weiner SJ, Sleeper LA, et al. Cerebrovascular accidentsin sickle cell disease: Rates and risk factors. Blood 1998;91:288–294.
3. Adams R, McKie V, Nichols F, et al. The use of transcranial ultrasonographyto predict stroke in sickle cell disease. N Engl J Med 1992;326:605–610.
4. Cohen AR, Martin MB, Silber JH, et al. A modified transfusion program forprevention of stroke in sickle cell disease. Blood 1992;79:1657–1661.
5. Miller ST, Jensen D, Rao SP. Less intensive long-term transfusion therapy forsickle cell anemia and cerebrovascular accident. J Pediatr 1992;120:54–57.
6. Aygun B, McMurray MA, Schultz WH, et alfor the SWiTCH Trial Investigators.Chronic transfusion practice for children with sickle cell anemia and stroke. BrJ Haematol 2009;145:524–528.
7. Adams RJ. Lessons from the stroke prevention trial in sickle cell anemia(STOP) study. J Child Neurol 2000;15:344–349.
8. Lee MT, Piomelli S, Granger S, et al. STOP Study Investigators. Stroke Pre-vention Trial in Sickle Cell Anemia (STOP): Extended follow-up and finalresults. Blood 2006;108:847–852.
9. Adams RJ, Brambilla D. Optimizing primary stroke prevention in sickle cellanemia (STOP 2) trial investigators. Discontinuing prophylactic transfusionsused to prevent stroke in sickle cell disease. N Engl J Med 2005;353:2769–2778.
10. Kwiatkowski JL, Yim E, Miller S, Adams RJ;for the STOP 2 Study Investiga-tors. Effect of transfusion therapy on transcranial Doppler ultrasonographyvelocities in children with sickle cell disease. Pediatr Blood Cancer 2011;56:777–782.
11. Mirre E, Brousse V, Berteloot L, et al. Feasibility and efficacy of chronic trans-fusion for stroke prevention in children with sickle cell disease. Eur J Haema-tol 2010;84:259–265.
12. Hulbert ML, McKinstry RC, Lacey JL, et al. Silent cerebral infarcts occurdespite regular blood transfusion therapy after first strokes in children withsickle cell disease. Blood 2011;117:772–779.
Appendix
TWiTCH Trial investigators and coordinators:TWiTCH Trial investigators and key contributors include the following: Bri-
gitta Mueller and Bogdan Dinu (Baylor College of Medicine, Houston, TX);
Kusum Viswanathan and Natalie Sommerville-Brooks (Brookdale Hospital
Medical Center, Brooklyn, NY); Clark Brown and Betsy Record (Children’s
Healthcare of Atlanta, Atlanta, GA); Matthew Heeney and Meredith Ander-
son (Children’s Hospital Boston, Boston, MA); Janet L. Kwiatkowski, Jeffrey
Olson and Martha Brown, (Children’s Hospital of Philadelphia, Philadelphia,
PA); Lakshmanan Krishnamurti and Regina McCollum (Children’s Hospital of
Pittsburgh, Pittsburgh, PA); Kamar Godder and Jennifer Newlin (Children’s
Hospital of Richmond, Richmond, VA); William Owen (Children’s Hospital of
the King’s Daughters); Stephen Nelson (Children’s Hospitals and Clinics of
Minnesota, Minneapolis, MN); Alexis A. Thompson and Katie Bianchi (Child-
ren’s Memorial Hospital, Chicago, IL); Lori Luchtman-Jones and Sheronda
Brown (Children’s National Medical Center, Washington, DC); Margaret Lee
(Columbia University, New York, NY); Courtney Thornburg (Duke University
Medical Center, Durham, NC); Charles Daeschner and Cynthia Brown (East
Carolina University, Greenville, NC); Sherron Jackson and Lisa Kuisel (Med-
ical University of South Carolina, Charleston, SC); Ramamoorthy Naga-
subramanian (Nemours Children’s Clinic Orlando, Orlando, FL); Cynthia
Gauger (Nemours Children’s Clinic, Jacksonville, FL); Brian Berman and
Mary DeBarr (Rainbow Babies and Children’s Hospital, Cleveland, OH);
Sharon Singh and Antonella Farrell (Schneider Children’s Hospital, New
Hyde Park, NY); Banu Aygun and Eileen Hansbury (St. Jude Children’s
Research Hospital, Memphis, TN); Scott Miller and Kathy Rey (SUNY Down-
state, Brooklyn, NY); Isaac Odame, Nagina Parmar, and Manuella Merelles-
Pulcinni (The Hospital for Sick Children, Toronto ON Canada); Zora R Rog-
ers and Leah Adix (The University of Texas Southwestern Medical Center,
Dallas, TX); Lee Hilliard and Jeanine Dumas (University of Alabama, Bir-
mingham, AL); Michelle Neier and Stephanie Farias (University of Medicine
and Dentistry of New Jersey, New Brunswick, NJ); Ofelia Alvarez and Pat-
rice Williams (University of Miami, Miami, FL); Rathi Iyer and Mary T. Walker
(University of Mississippi Medical Center, Jackson, MS); Hamayun Imran
and Stephanie Durggin (University of South Alabama, Mobile, AL); Elizabeth
Yang (Vanderbilt University, Nashville, TN); Sharada Sarnaik and Mary Mur-
phy (Wayne State University, Detroit, MI).
Initial experience from a double-blind, placebo-controlled,clinical outcome study of ARC1779 in patients with thromboticthrombocytopenic purpuraSpero R. Cataland,1* Flora Peyvandi,2 Pier M. Mannucci,2 Bernhard Lammle,3 Johanna A. Kremer Hovinga,3
Samuel J. Machin,4Marie Scully,4 Gail Rock,5 James C. Gilbert,6 Shangbin Yang,1 Haifeng Wu,1
Bernd Jilma,7 and Paul Knoebl8
Despite advances in our understanding of the pathophysiology of
thrombotic thrombocytopenic purpura (TTP), there remains significant
room for improvement in the treatment of acute TTP. A novel approach
to the treatment of TTP using ARC1779 to target the A1-domain of von
Willebrand Factor (VWF) to prevent the formation of microthombi has
been developed. Preliminary data suggests that blockade of the A1-
domain of VWF by ARC1779 can inhibit VWF activity, resulting in clini-
cally significant improvements in the platelet count and lactate dehy-
drogenase [1–5]. ARC1779 is a nucleic acid macromolecule, or
aptamer, that inhibits the prothrombotic function of VWF by binding to
letters
430 American Journal of Hematology
theA1-domain
ofVWF,blocking
itsinteractio
nwith
the
plateletGPIb
receptor.
Ithas
been
hypothesize
dthatARC1779prevents
the
form
a-
tionofnew
microthrombiin
patie
nts
with
acute
TTP,andmayresultin
shorte
rcoursesofplasmaexchange(PEX)and
fewerend
organ
com-
plic
atio
ns
via
the
more
rapid
inhibitio
nofmicrothrombotic
disease.
Prio
rto
thepremature
closure
ofthestudy,
ninepatie
nts
were
treated
with
eith
erARC1779
ofplacebo
as
an
adjunctto
PEX.Alth
ough
lim-
ited,these
data
support
the
safety
ofthis
targeted
approach
tothe
treatm
ent
ofTTP,providing
the
basis
for
contin
ued
study
of
this
uniqueapproachto
therapy.
Patie
ntenrollm
ent.
Atotalofnine
subjects
(seve
nARC1779,two
Place
bo)were
enrolledatsix
siteswhenthestu
dywasclo
sed.Demographic
andclin
icaldetails
oftheenrolledsu
bjects
are
shownin
Table
I.ADAMTS13
activity
wasava
ilable
from
6/7
ARC1779-tre
atedsu
bjects
andboth
place
bo
subjects.
Clinica
lresp
onse
.Clinica
lresp
onse
criteria
were
ach
ieve
dby4/7
sub-
jects
on
the
ARC1779
arm
,and
0/2
place
bo
subjects
prio
rto
the
end
of
the
14-day
infusio
nperio
d.
For
the
4ARC1779-tre
ated
subjects,
the
median
numberofPEX
proce
dures
toach
ieve
resp
onse
criteria
was
7
(range,
6–9).
Three
ARC1779-tre
ated
patie
nts
did
not
meet
clinica
l
resp
onse
criteria
by14days.
Ofthese
onemettheclin
icalresp
onse
crite-
riaon
Day
17,and
one
additio
nalsu
bject
metthe
criteria
atthe
6-w
eek
follow-up
visit,afte
rjudged
tobe
refra
ctory
toARC1779
afte
r9
days
of
therapyand
rece
iving
treatm
entwith
rituxim
ab,vin
cristine,and
cyclophos-
phamide.Oneadditio
nalARC1779-tre
atedpatie
ntach
ieve
danorm
alplate-
letco
untonDay4,butonDay6PEX
washeld
asapart
ofthetaperin
g
ofPEX
while
the
ARC1779
wasco
ntin
ued
with
outtaperin
ggive
nthatthe
plateletco
untwasnorm
alforonly
2co
nse
cutive
days.
He
beca
me
throm-
bocyto
penic
on
the
following
day
afte
rholding
PEX
for1
day
and
while
rece
ivingARC1779aloneandwasneve
rable
toach
ieve
anorm
alplatelet
countbefore
the
end
ofthe
14-dayinfusio
nperio
ddesp
itethe
resu
mptio
n
ofdaily
PEX.Tw
odays
afte
rthe
disco
ntin
uatio
nofARC1779
(afte
rtaper-
ing
completed,butco
ntin
uing
daily
PEX)the
patie
ntwasnoted
tohave
a
rising
troponin-I
[9.79
and
17.14
ng
mL21on
2co
nse
cutive
days
(norm
al
<0.11
ng
mL21)]
asmeasu
red
inthe
loca
lclin
icallaboratory.
Three
days
afte
rthe
ARC1779
infusio
nwassto
pped
his
troponin-I
remained
eleva
ted
at14.52
ng
mL21and
he
suffe
red
aca
rdiacarre
stand
died.One
ofthe
twoplace
bo-tre
atedpatie
nts
ach
ieve
danorm
alplateletco
untafte
r14daily
PEX
proce
dures,
butthe
otherplace
bo-tre
ated
patie
ntremained
seve
rely
thrombocyto
penic
on
day13,eve
ntually
ach
ievin
ga
norm
alplateletco
unt
atthe
6-w
eekfollow-upvisit
afte
rtherapywith
rituxim
ab.Forthefive
sub-
jects
who
ach
ieve
da
norm
alplateletco
unton
ARC
1779
(inclu
ding
the
subject
who
ach
ieve
da
norm
alplateletco
untbutdid
notmeetresp
onse
criteria
),themediannumberofdaily
PEX
proce
duresto
ach
ieve
aplatelet
countof>1503
109/L
was5(ra
nge,4–14).
ARC1779
conce
ntra
tion
and
VWF
activity.
Seria
lVWF
activity
and
ARC1779co
nce
ntra
tionswere
studiedto
judgetheeffica
cyofARC1779in
term
soffre
eA1domainsasasu
rroga
teforVWFactivity
(Fig.1).The
sedata
demonstra
tedthesu
staine
dsu
ppression
ofVWFactivity
(decre
ase
dava
ilable
A1domain
sites)throug
hou
tthe14-d
ayinfusio
nwith
recove
ryto
norm
alleve
ls
after
thetape
ringand
disco
ntinuation
oftheinfu
sion.
Adve
rseeve
nts.
Subjects
randomize
dto
ARC1779
arm
ofthe
study
exp
erie
nce
dthe
following
serio
us
adve
rseeve
nts:
mentalsta
tus
changes
(2),
seizu
rediso
rder
(1),
catheter-re
lated
thrombosis
(1),
and
catheter-
relatedse
psis
(1).
Thementalsta
tusch
angesin
both
subjects
were
deter-
mined
tonotbe
related
tothe
studydrug.In
the
case
ofthe
firstpatie
nt,
theyoccu
rred30days
afte
rherlast
dose
ofARC1779andin
theco
ntext
of
multip
leacu
teinfarctio
ns
ofthe
cerebralhemisp
heres
and
cerebellum.
Give
nthe
recu
rrentthrombocyto
penia
atthe
time
ofprese
ntatio
n,a
recu
r-
rence
ofTTP
wasfeltto
bethemost
likely
etio
logyoftheacu
teinfarctio
ns
andthesu
bse
quentmentalsta
tusch
anges.
Inthese
condpatie
nt,themen-
talsta
tusch
angesand
ase
izure
diso
rderwere
noted
tooccu
rco
incid
ent
with
arecu
rrentthrombocyto
penia
consiste
ntwith
arecu
rrence
ofTTP.
Imaging
ofhis
brain
by
CT
showed
no
abnorm
alitie
s,and
symptoms
improve
dwith
thereinitia
tionofPEX
therapy.
Intheopinionofthetre
atin
g
physicia
ns,
these
serio
usadve
rseeve
nts
were
notthoughtto
berelatedto
ARC1779,butratherwere
relatedto
thediagnosis
ofTTP
andtherelated
therapy
(catheter-re
lated
complica
tions).
No
serio
us
adve
rseeve
nts
were
reporte
don
the
place
bo
arm
ofthe
study.
No
ARC1779-tre
ated
subjects
TABLE I. Demographic and Clinical Data (Median) at Presentation and Responses to Therapy for all Nine Enrolled Subjects
Median age(range) Sex (M/F)
Race(AA/C)
PretreatmentADAMTS13%a
Platelet count(3109/L) LDH (U/L)
Creatinine(mg dl21)
Clinical response(!14 days)
Immune suppressivetherapy Adverse events
ARC1779 (n 5 7) 44 (33–51) 4/3 3/4 72 (<2.5–100) 16 1,063 (263–1,804) 1.31 (0.8–2.46) 4/7 Corticosteroids (4);Rituximab (1);CSA (1);Vincristine (1)
Mental status changes (2)a;catheter-related Sepsis (1)a;catheter-related DVT (1)a
Placebob(n 5 2) 32, 70 0/2 0/2 <2.5, 42% 16 647, 1,258 4.54, 0.99 0/2 Corticosteroids (1) None
All adverse events reported were judged to not likely be related to the study drug.aFour of 8 ADAMTS13 measurements were obtained after the first PEX procedure but prior to the first dose of ARC1779.bGiven that there were only two subjects in the placebo arm, data for both subjects rather than the median data are presented.
letters
American
Journalof
Hem
atology431
experienced bleeding symptoms including cutaneous purpura or petechiae
during the infusions despite sustained suppression of ‘‘VWF activity’’ in sub-
jects with platelet counts as low as 6 3 109/L.
Despite the premature closure of this study, there are significant observations
that can be made from these nine patients that were enrolled. With the bolus
primed continuous infusion of ARC1779, sustained suppression of VWF activity
(free A1 domain sites) relative to pretreatment activity was achieved. The sup-
pression of VWF activity correlated with plasma concentrations of ARC1779,
and recovered with tapering and discontinuing the ARC1779 infusion. Clinical
responses were also consistent with what has been reported previously with
ARC1779. It is not clear if a more sustained inhibition of VWF activity below the
goal of 10% of baseline VWF activity would improve the efficacy, but it is worth
noting that there were no hemorrhagic complications seen in the pilot study
where the mean VWFactivity during the ARC1779 infusion was 5%.
The most important conclusion that could be drawn from these preliminary
data would be that the drug was well-tolerated by the patients studied. Con-
cern would be justified regarding the potential for bleeding complications
that might arise from inhibiting VWF activity in patients already severely
thrombocytopenic (median platelet count 16 3 109/L at presentation). How-
ever, despite achieving sustained suppression of VWF activity throughout
the continuous infusion of ARC1779, no patient experienced bleeding com-
plications. Despite the absence of any observed bleeding complications,
additional study is required to confirm the safety of sustained reductions to
<10% VWF activity in severely thrombocytopenic TTP patients.
These data suggest that the addition of ARC1779 to PEX may have
decreased the number of exchanges to achieve a normal platelet count, but
with only two patients in the placebo group it is not possible to draw defini-
tive conclusions. It is clear that ARC1779 does not alter the basic disease
process that results in the initiation of microthrombus formation in patients
with TTP, but rather prevents the formation of VWF-mediated microthrombi.
The patient described who achieved a normal platelet count, but developed
a recurrent thrombocytopenia while receiving ARC1779 but holding PEX for
one day provides an illustration of this point. Despite continued therapy with
ARC1779 at the intended dose, the patient clinically deteriorated, developing
recurrent thrombocytopenia consistent with an acute exacerbation of TTP.
Effective suppression of the ADAMTS13 inhibitory antibody via PEX or adju-
vant immune suppressive therapy is still required to achieve a sustained
remission of TTP. With this approach, ARC1779 or a similar agent could pro-
vide more immediate protection until the disease process can be sup-
pressed by PEX and/or immune suppressive therapy.
While limited in number and longitudinal follow-up, these data provide sup-
port for the continued study of VWF A1 inhibition as an adjunct to PEX in
the treatment of TTP. These therapies should however be viewed as protec-
tive agents that do not alter the underlying pathophysiology, and therefore
should be administered as an adjunct to PEX and/or immune suppressive
therapy in patients with acquired TTP.
MethodsStudy methodology. ARC1779-006 was a randomized, double-blinded,
placebo controlled multicenter, international study in patients with TMA with
a planned randomization ratio of ARC1779 to placebo of 3:1(ClinicalTrials.-
gov Identifier: NCT00726544). The objectives of the study were to evaluate:
(1) the safety and tolerability of ARC1779, (2) the concentration-response of
ARC1779 in terms of efficacy and safety related effects, and (3) the ability
of ARC1779 to prevent or minimize short-term neurologic, cardiac, and renal
injury from an acute episode of TTP. The study was intended to enroll 100
subjects, but was terminated prematurely by the sponsor after enrolling nine
subjects for financial reasons.
Eligible subjects included adults 18–75 years of age with a diagnosis of a
TMA (platelet count of <100 3 109/L and microangiopathic hemolytic
anemia without an alternative explanation). Patients with pregnancy-associ-
ated TMA were eligible if no longer pregnant or breast-feeding. Patients with
both initial and relapsed events were eligible. The volume of PEX and
decision regarding adjuvant immune suppressive therapy were left to the
discretion of the treating physician. Subjects randomized to ARC1779
received an initial loading dose of 0.21 mg kg21 followed by a continuous
infusion at a rate of 0.6 mg/kg/min. After each PEX, a repeat loading dose
at 50% of the initial loading dose was administered to rapidly restore
ARC1779 concentrations after the removal of drug by PEX. ARC1779 or
placebo was continued until achieving a clinical response (platelet count
=150 3 109/L on 3 consecutive days) or for a maximum of 14 days. The
infusion (ARC1779 or placebo) was then decreased by 50% on day 11, by
an additional 50% on day 12, and discontinued on day 13. PEX was
tapered at the discretion of the treating physician.
Efficacy was assessed by the serial measurement of complete blood
counts (CBC) and the lactate dehydrogenase (LDH). Bleeding complications
were monitored and reported by the treating physician who reported any
clinical bleeding symptoms and findings including minor skin bleeding, both
during therapy and the planned 6-week follow-up.
1Department of Medicine and Pathology, Ohio State University, Columbus, Ohio;2U.O.S. Dipartimentale per la Diagnosi e la Terapia delle Coagulopatie, A. Bianchi
Bonomi Hemophilia and Thrombosis Center, IRCCS Ca Granda FoundationMaggiore Policlinico Hospital, Milan, Italy; 3Department of Hematology, UniversityHospital Bern, Bern, Switzerland; 4University College London Hospitals, London,United Kingdom; 5Department of Pathology, University of Ottawa, Ottawa, ON,Canada; 6Archemix Corp., Cambridge, Massachusetts; 7Department of Clinical
Pharmacology, Medical University of Vienna, Wien, Austria; 8Department ofInternal Medicine, Medical University of Vienna, Vienna, Austria
Contract grant sponsor: Archemix CorpBernd Jilma and Paul Knoebl are senior authors.
*Correspondence to: Spero R. Cataland, M.D., Department of Internal Medicine,Ohio State University, A361 Starling Loving Hall, 320 W. 10th Ave., 306B Starling
Loving Hall, Columbus, OH 43210E-mail: [email protected]
Conflict of interest: SRC, FP, PMM, BL, JKH, SJM, MS, GR, BJ, and PK all servedas consultants to the Archemix Corp. JCG was employed by the Archemix Corp
Published online 29 December 2011 in Wiley Online Library(wileyonlinelibrary.com).DOI: 10.1002/ajh.23106
References
1. Bouchard PR, Hutabarat RM, Thompson KM. Discovery and development oftherapeutic aptamers. Annu Rev Pharmacol Toxicol 2010;50:237–257.
2. Knobl P, Jilma B, Gilbert JC, et al. Anti-vonWillebrand factor aptamer ARC1779 forrefractory thrombotic thrombocytopenic purpura. Transfusion 2009;49:2181–2185.
3. Gilbert JC, DeFeo-Fraulini T, Hutabarat RM, et al. First-in-human evaluationof anti von Willebrand factor therapeutic aptamer ARC1779 in healthy volun-teers. Circulation 2007;116:2678–2686.
4. Diener JL, Daniel Lagasse HA, Duerschmied D, et al. Inhibition of von Willebrandfactor-mediated platelet activation and thrombosis by the anti-von Willebrand fac-tor A1-domain aptamer ARC1779. J Thromb Hemost 2009;7:1155–1162.
5. Jilma-Stohlawetz P, Gorczyca ME, Jilma B, et al. Inhibition of von Willebrandfactor by ARC1779 in patients with acute thrombotic thrombocytopenic pur-pura. J Thromb Hemost 2011;105:545–552.
Figure 1. Shown in the figure above are the median ARC1779 concentrations andfree VWF A1 domains (‘‘VWF activity’’) for the ARC1779-treated patients throughoutthe 14-day dosing period. The number above each data point reflects the number ofsamples studied at each time point. Day 11 and 13 represent the first 50% taperingof ARC1779 and the time of discontinuing ARC1779 respectively.
letters
432 American Journal of Hematology
(Arterioscler Thromb Vasc Biol. 2012;32:00-00)
• DNA/RNA Aptamer gekoppelt an 40 kDa PEG
• Selektiert auf hochaffine Bindung an VWF A1 Domänen
• in vivo PK/PD Studien in Cynomolgus Affen
• ex vivo Studien in Patienten mit Myokardinfarkt
• Verschiedene in vitro Studien (Elektronenmikroskop, Flusskammer)
ARC 15105
PK/PD data of ARC 15105 in cynomolgus monkeys
• Bivalentes 28 kD Nanobody
• Positive präklinische Daten
• Potente Inhibition der
Thrombozytenaggregation ohne erhöhtes
Blutungspotential
• Inhibition von Thrombozytenadhäsion an
ULVWF und Thrombozyten-Stringbildung
• Potentielle klinische Vorteile bei TTP: • Verbesserte Effizienz und Sicherheit
• sc. Gabe
• Lange Halbwertszeit (48h)
Anti-VWF Nanobody
Conventional antibody
Heavy-chain antibody
VH VL CL
CH1
CH3
CH2 Ablynx’s Nanobody CH3
CH2
Camelidae family has both forms
VHH
VHH
Bivalent anti-VWF
Nanobody
Structure : courtesy of Steyaert et al, VUB
Anti-VWF Nanobody (ALX-0081/ALX-0681)= Caplacizumab
PE
PE 30 days
30 days
1 year follow-up
1 year follow-up
Primary endpoint time-to-response,
defined by recovery of platelets ≥ 150 G/L and confirmation at 48 h by de novo measure of platelet count ≥ 150 G/L and LDH ≤ 2 x ULN
Secondary endpoints • PE frequency and volume • relapse • exacerbations • mortality • major clinical events • recovery from signs and
symptoms
Ran
dom
isat
ion
Placebo
anti-VWF Nanobody
1:1
Inclusion criteria • men and women • 18 years or older • clinical diagnosis of TTP,
necessitating PE
Exclusion criteria • platelet count ≥ 100 G/L • severe active infection
indicated by sepsis • infection with E. coli 0157 or
related organism • anti-phospholipid syndrome,
DIC or congenital TTP • pregnancy or breast-feeding • active bleeding or high risk
of bleeding • uncontrolled arterial
hypertension • chronic anticoagulant
treatment • bone marrow carcinosis • severe liver impairment
n = 110
The TITAN trial: Study Design
• Intensivstations-Bett suchen (auch bei scheinbar guten Patienten, akute Verschlechterung jederzeit möglich)
• Organfunktion engmaschig überwachen (Herz, Hirn, Niere)
• Patient/in geeignet für klinische Studie? (PI anrufen)
• Citratplasma (8 Röhrchen) gewinnen für weitere Diagnostik (VOR Plasmaaustausch)
• Venenzugang beurteilen für Plasma-Austauschtherapie eventuell Quinton stechen (KEINE TK!)
• Plasma-Austausch anmelden
• Nierenersatztherapie (bei Bedarf)
• Immunsuppression 100 mg Solu-Dacortin iv.
• 4 Ery-Konz. kreuzen lassen
• TROTZDEM Differentialdiagnosen aufarbeiten…
Akutmanagement der TMA:
URSACHE BESEITIGEN (wenn möglich)
PLASMAAUSTAUSCH-‐Therapie: immer noch 1.Wahl Elimina,on von Autoan,körpern, Thrombozytenaggregaten, UL-‐VWF MM, Sludge; Zufuhr von ADAMTS13, normalem VWF Plasmaaustausch gegen FFP oder Octaplas®, täglich 50-‐80 ml/kg Pa,enten mit hereditärem ADAMTS13 Mangel sprechen prompt an
(Normalisierung der Thrombozyten nach 1-‐2 Behandlungen)
Pa,enten mit An'-‐ADAMTS13 An'körpern sprechen zunächst gut an (Thrombozytenans,eg), dann oX aber Exazerba,on nach ca. 1 Woche. => konsequente Weiterbehandlung !
Therapiedauer: bis Thrombozyten, LDH, Organdysfunk,on und Klinik normal, dann noch 3 x mit verlängerten Intervallen. Exazerba,on nach zu früher Beendigung häufig!
Behandlungsoptionen für TTP (i):
KEINE THROMBOZYTENKONZENTRATE !!!
Thrombozytenaggrega'onshemmer (Clopidogrel, ASS) überlegen bei prolongiertem Verlauf, Zeichen schwerer Organdysfunk,on, häufigen Relapsen, auch wenn Thrombozytenzahl niedrig
Behandlungsoptionen für TTP (ii):
Komplement-‐Inhibi'on: Eculizumab (Soliris®)
Bei nachgewiesenen oder vermuteten Autoan'körpern im Komplementsystem: Immunsuppression (z.B. Steroide, Rituximab)
Symptoma'sche Therapie: Nierenersatztherapie Plasmatherapie (bei manchen kongenitalen Defekten promptes Ansprechen) Suppor,ve Maßnahmen
Behandlungsoptionen für HUS:
Keine spezifischen Therapieop'onen
Absetzen des verdäch,gen Medikaments, Wechsel auf Alterna,vpräparat
Symptoma,sche Plasmaaustauschtherapie (meist wirkungslos)
Nierenersatztherapie
Suppor,ve Maßnahmen
OX „spontane“ Besserung nach mehreren Wochen/Monaten
Behandlungsoptionen sekundäre TMA:
Intensivüberwachung / -therapie: • Schwere Organdysfunktion möglich (Myokardinfarkt, Rhythmusstörungen, Insulte,
Epilepsie, Nierenversagen, Darmischämie,...) Akute Verschlechterung trotz Therapie möglich
Erythrozytentransfusionen: • Hb Grenzwert nicht definiert (< 7.0 g/dL, höher bei ACS)
Thrombozytentransfusionen: • NICHT in der Frühphase (Aggravierung der Mikrozirkulationsstörungen möglich).
Blutungsrisiko niedrig, trotz Thrombopenie (außer bei gestörter Hämatopoese – SZT, Virusinfekte, Medikamente)
TVT Prophylaxe: • LMWH zur Thromboseprophylaxe auch bei niedrigen Thrombozytenwerten.
Infektionsprophylaxe: • Infektionen (Katheter, Pneumonie, etc.) können akute Verschlechterung der TMA
verursachen. Verschleiert durch Steroid-Therapie.
Supportivtherapie:
Zusammenfassung: • Die Prognose der TTP konnte durch die Plasmaaustauschtherapie deutlich
verbessert werden, aber Mortalität und Morbidität sind immer noch hoch. Plasmaaustausch ist oft nur eine symptomatische Behandlung.
• Das heutige Verständnis der Pathophysiologie der TTP eröffnet modernere, zielgerichtete Behandlungsformen: - Beeinflussung der Plättchen-VWF Interaktion zur Verhinderung der
Organschädigungen in der akuten Phase der Erkrankung - Unterbrechung des Autoimmunprozesses als kausale Therapie zur
Verhinderung von Relapsen - Zufuhr von ADAMTS13 als zielgerichtete Substitution bei ADAMTS13
Mangel • Weniger eindeutige Fortschritte beim HUS, Soliris® bei Komplement-
Überaktivierung
• Praktisch keine neuen Ansätze bei sekundären TMA-Formen