First results of the Phase II TITAN trial: anti-von Willebrand ... - Ablynx

First results of the Phase II TITAN trial:
anti-von Willebrand factor Nanobody®
as adjunctive treatment for patients with
acquired thrombotic thrombocytopenic purpura
Flora Peyvandi, Dimitri A. Breems, Paul Knoebl,
Caroline De Man, Ka Lung Wu, Christophe Lyssens,
Josefin-Beate Holz
Nanobodies ® -
Inspired by nature
XXIII Congress of the International Society of Thrombosis and Hemostasis
- Late Breaking Clinical Research Symposium -
Kyoto, Japan, July 28th, 2011

TTP: thrombotic thrombocytopenic purpura
• Is an acute life threatening disorder, characterised by:
– microangiopathic haemolytic anaemia
– thrombocytopaenia
– microvascular thrombosis that causes variable degree of tissue ischaemia
and infarction
• Rare: 5-11 cases per million people per year
• PE (plasma exchange) decreased mortality from 90% to 10%
• M:F ratio = 1:3
• 5% congenital and 95% acquired
• 20-30% risk of recurrence
2

Clinical symptoms at the first three episodes
• 33 patients with 3 or more disease episodes
p

Classification of TTP
Congenital
5%
Acquired
95%
Secondary
50%
Idiopathic
(autoimmune)
50%
• Drugs
• Autoimmune
disease
• Infections and HIV
• Tumours
• Pregnancy
4

ADAMTS13
• VWF cleaving protease (ADAMTS13) cleaves
ULVWF as soon as these molecules are released
by injured or activated endothelial cells
• The importance of VWF regulation by ADAMTS13
is demonstrated by the close association between
severe deficiency of ADAMTS13 activity and
clinical TTP
5

Rationale of TTP therapy
Congenital TTP Acquired TTP
Supply ADAMTS13
Remove the ULVWF
and anti-ADAMTS13 Ab
Supply ADAMTS13
Plasma infusion PE
Reduce
anti-ADAMTS13 Ab
production
Steroids
Immunosuppressives
6

Treatment of acute TTP
• Survival of patients with TTP
Rock et al, NEJM 1991
7

Major complications of PE
• Experience of the Oklahoma TTP-HUS registry, 1996-2008
% of patients
14
12
10
8
6
4
2
0
3
Death Non fatal
cardiac arrest
1
2
Catheter
insertion
complications
12
Systemic
infection
7
Catheter
obstruction
3
Hypotension Venous
thrombosis
2
George et al, Blood 2010
8

Immunosuppressive agents
• Corticosteroids
– the use of glucocorticoids is based only on clinical experience and case
series
(Vesely et al Blood 2003, Perotti et al Haematologica 1996, Coppo et al BJH 2006, Cataland et al BJH 2007)
– in combination with PE increased complete remission rate and decreased
exacerbation and relapse rates
(Vesely et al Blood 2003, Coppo et al BJH 2006, Cataland et al BJH 2007, Baduini et al Ann Hematol 2010)
• Rituximab
– 95% had a complete clinical and laboratory response within 1-3 weeks
– mild acute reactions to rituximab infusions easily managed
– more serious complications were uncommon
– number of PE to remission, inpatient stay and relapse rate reduced
(Gutterman LA et al Blood Cells Mol Dis 2002, Galbusera M et al Blood 2005, Herbei L & Venugopal P Clin
Adv Hematol Oncol 2006, Scully M et al BJH 2007, Heidel F et al TH 2007, Patino W & Sarode R J Clin Apher
2007, Scully M et al BJH 2008, Bresin E et al TH 2009, Scully M et al Blood 2011)
9

Treatment outcome
• Disease duration is variable
• The clinical response is usually achieved after 9-16 days of plasma
therapy
• Mortality reduced to 10-20% with PE, but still high
• Mortality is highest in the first days from disease onset
• Exacerbation: new clinical signs and symptoms within 30 days after
normalisation of platelet count (25-50%)
• Relapse: new clinical sign and symptoms more than 30 days after
normalisation of platelet count (20-30%)
(Rose M et al Am J Med 1987, Rock GA et al NEJM 1991, Bell WR et al NEJM 1991, Onundarson PT et al Ann
Intern Med 1992, Thompson CE et al Blood 1992, Hayward CP et al Arch Intern Med 1994, Sarode R et al Am J
Hematol 1997, Lara PN Jr et al Am J Hematol 1999, Burns ER et al Am J Hematol 2004, Zheng Xl et al Blood
2004, Scully M et al BJH 2006, Sadler JE Blood 2008)
10

Perspectives
• Recombinant ADAMTS13 (Baxter)
• Anti VWF-GPIb agents:
─ ARC-1779 aptamer (Archemix - Baxter)
─ ALX-0081 Nanobody (Ablynx)
─ rGPG 290 (Aarvon Biosciences)
• Novel anti-CD20 products (LFB, Roche etc)
11

Anti-VWF Nanobody (ALX-0081/ALX-0681)
• Bivalent 28 kD Nanobody
– new mode of action
– stops platelet adhesion to vessel wall at
high blood flow
• Positive preclinical data
– potent inhibition of clotting without
increasing bleeding potential
– in vitro inhibition of platelet adhesion to
ULVWF and of platelet string formation
• Potential clinical benefits
– improved efficacy and safety as adjunct
to plasma exchange
Camelidae family has both forms
C H2
C H3
CH1 CL Conventional
antibody
Bivalent
anti-VWF
Nanobody
V H
V L
C H2
C H3
V HH
Heavy-chain
antibody
V HH
Ablynx’s
Nanobody
Anti-VWF
Nanobody
Structure : courtesy of Steyaert et al, VUB
12

ALX-0081: mode of action in TTP
• Endothelial cells release ULVWF multimers, which are unfolded by shear stress
and subsequently processed by ADAMTS13 into smaller multimers
• Normal VWF multimers require conformational activation for platelet interaction
• In TTP, ADAMTS13 is dysfunctional and ULVWF becomes
activated allowing the formation of unwanted platelet
aggregates.
Shear stress
Release of UL-VWF
Endothelium
Subendothelium
Conformational
change
Persistence of
UL-vWF multimers
Anti-VWF
Nanobody
Platelet string formation
13

ALX-0081 binds the N-terminus of the VWF A1-domain
A1-vWF
C
N
GPIbα
Monovalent building
block of ALX-0081
PDB 1M10 (complexed A1-VWF)
Ablynx A1-VWF-Nb structure
CDR2
CDR3
N
CDR1
C
14

ALX-0081 potently neutralises ULVWF in vitro
• Effective concentrations linked with VWF:Ag levels
Ex vivo platelet string formation
ULvWF
ULvWF and anti-vWF Nanobody
Anti-vWF Nanobody inhibits platelet string formation caused by
ULvWF in plasma of TTP patients
15

Clinical studies with ALX-0081 related to TTP indication
Phase Population n Regimen/dose Status
I
Healthy
volunteers
I Healthy
volunteers
II
Patients with
acquired
TTP
• Clinical status
40
36
110
– Phase I trials successfully completed, up to 14d treatment well tolerated, no
immunogenicity (limited exposure), mild bleeding and bruising, partial decrease of
VWF:Ag and FVIII activity levels
Single dose
i.v. infusion
0.5-12 mg
Single and multiple dose
s.c.
2–16 mg and 10 mg (7-14 d)
Multiple doses
i.v. and s.c.
10-20 mg/d as adjunct to PE
– Phase II (acquired TTP) primary endpoint: time-to-platelet recovery
Completed – final
study report
Completed - final
study report
Ongoing
16

The TITAN trial: study design
Inclusion criteria
• men and women
• 18 years or older
• clinical diagnosis of TTP,
necessitating PE
Exclusion criteria
• platelet count ≥ 100,000/µL
• 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
Randomisation
1:1
n = 110
PE
PE
Primary endpoint
time-to-response,
Placebo
anti-VWF Nanobody
defined by recovery of
platelets ≥ 150,000/µL
and confirmation at 48 h by
de novo measure of
platelet count ≥ 150,000/µL
and LDH ≤ 2 x ULN
30 days
30 days
1 year follow-up
1 year follow-up
Secondary endpoints
• PE frequency and volume
• relapse
• exacerbations
• mortality
• major clinical events
• recovery from signs and
symptoms
17

1:1
Study treatment and schedule
Recruitment
Randomisation
ALX-0081
Placebo
Prior to
first PE
single
i.v. bolus
(10 mg)
Treatment phase
PE period
s.c. doses
(10 mg)
1 or 2/day
based on RiCo
assay
Post-PE
(30 days)
s.c. doses
(10 mg)
1 or 2/day
based on RiCo
assay
Follow-up
(1 year)
Primary endpoint Secondary endpoints
18

Nanobodies ® -
Inspired by nature

PD measurement
• RICO/RIPA assay as only suitable assay to assess specifically full
neutralisation of (UL)VWF by ALX-0081
Assay Test principle Pro Con
RIPA
RICO
vWF:Act
PFA-100
VWF-mediated aggregation
of autologous platelets by
ristocetin
VWF-mediated aggregation
of fixed platelets by
ristocetin
Immunoassay with mAb
that interacts with GPIbbinding
region in VWF
High shear flow system to
measure platelet adhesion
and aggregation upon
stimulus
Correlates with preclinical
efficacy of ALX-0081 (ACS)
• Demonstrated equivalence
to RIPA
• Can be performed on
frozen samples
Easy, high throughput
• Requires specific
equipment
• Low throughput
• Fresh samples
• Requires specific
equipment
• Low throughput
No inhibition of response by
ALX-0081
Easy, high throughput Aspecific: interference of
comedication
20

Demographic and baseline characteristics (1)
• 2 men and 3 women
• 3 on Nanobody treament, 2 on placebo
• 4 with first episode of TTP, 1 with recurrent TTP
• clinical symptoms at presentation:
– 10 neurological
– 4 purpura + other cutaneous bleeding manifestations
– 2 non-cutaneous bleeding
– 2 gastrointestinal
– 2 cardiovascular
– 1 other
21

Demographic and baseline characteristics (2)
Parameter n Mean (SD) Min-max
Age (years) 5 46 (12) 31-60
Weight (kg) 5 85 (30) 52-118
BMI (kg/m²) 5 31,3 (9,7) 20-45
Platelet count (10 9 /L) 5 27 (15) 7-41
LDH (U/L) 5 1646 (880) 909-2795
RICO (%) 5 95 (35) 41-120
vWF:Ag (%) 5 233 (126) 114-420
Nanobodies ® FVIII:C (%) 5 197 (89) 76-315 -
ADAMTS13 (CBA) (%) 4 39 (38) Inspired by

PE details
• PE treatment
– variable duration of PE treatment: 5-23 days
– type of plasma used: fresh frozen plasma, Octoplas BG A or VPVI
methylene blue
– volume of plasma administered: 2500-4400 mL
• Use of concomitant glucocorticoids or other immunosuppressants
– methylprednisone: 5/5 subjects
– rituximab: 1/5 subjects
23

Preliminary observations: platelet count (n = 5/110)
24

Preliminary observations: RiCo (n = 5/110)
Normal range
25

Preliminary observations: VWF:Ag (n = 5/110)
Normal range
26

Preliminary observations: FVIII acitivity (n = 5/110)
27

Normal range
Preliminary observations: ADAMTS13 (n = 5/110)
Normal range
Nanobodies ® -
Inspired by nature
28

Preliminary observations: anti-ADAMTS13 Abs (n = 5/110)
Normal range
Nanobodies ® -
Inspired by nature
29

Preliminary observations: ULVWF ratio (n = 5/110)
Normal range
30

Serious adverse events
• 2 SAEs reported in 2/5 subjects during treatment phase:
– metrorrhagia with severe anaemia
o1 subject in perimenopausal period
oresolved
ostudy drug discontinued, subject withdrew consent
oconsidered possibly related to study drug by the Investigator → but in
perimenopausal age, the most common cause of abnormal vaginal bleeding
is anovulation (Nesse RE, Am Fam Physician 1999, James A et al. Eur J Obstet Gynecol Reprod Biol
2011)
– Urinary tract infection
o1 subject
oresulting in hospitalisation
oresolved
oconsidered unlikely/not related to study drug by the Investigator
31

Conclusions
• ALX-0081 in combination with PE is under clinical investigation as a
novel therapeutic approach to reduce the days of PE therapy and
accelerate the recovery of TTP patients
• The current Phase II trial is designed to assess the efficacy and
safety of ALX-0081 in TTP patients, in particular to characterise
potential bleeding risk of temporary, ‘therapeutic’ suppression of
VWF-mediated platelet aggregation
32

Acknowledgements
• Hemophilia and Thrombosis Center, Fondazione IRCCS
Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy
– Roberta Palla
– Maria Teresa Bajetta
– Luciano Baronciani
– Giuseppe Bettoni
– Maria Teresa Canciani
– Silvia La Marca
– Ilaria Mancini
– Silvia Pontiggia
– Francesca Stufano
– Carla Valsecchi
• Hospital Network Antwerp, campus Stuivenberg, Belgium
– Dimitri Breems
– Caroline De Man
– Ka Lung Wu
• Medical University of Vienna, Austria
– Paul Knoebl
• University College London Hospitals, UK
– Sam Machin
– Marie Scully
– Ian Mackie
• Ablynx
• CROs:
– Bernard Delaey
– Christophe Lyssens
– Christian Duby
– Dominique Tersago
– Femke Van Bockstaele
– Hans Ulrichts
– Josi Holz
– Katrien Verschueren
– I3 research
– PRA international
33