Novel Targeted Thorium Conjugates:
High-Energy Alpha Pharmaceuticals
6th World ADC, San Diego, October 21, 2015
Urs Hagemann
Bayer/Thorium Conjugate Research/Oslo
Disclosure Information
 I have the following financial relationships to disclose:
 I am an employee of Bayer AS
 I will not discuss off-label use and / or investigational use in my presentation
Page 2 • 6th ADC Summit San Diego, 2015
Agenda
 Introduction to Targeted Thorium Conjugates (TTCs)
 Case Study I: CD33-TTC targeting Acute Myeloid Leukemia (AML)
 Case Study II: CD70-TTC targeting Renal Cell Carcinoma (RCC)
 Case Study III: CD22-TTC targeting B-cell malignancies
Page 3 • 6th ADC Summit San Diego, 2015
The Actinides
Thorium-227 belongs to the actinide
series of elements
 Heavy, unstable and consequently
radioactive elements
 Alpha emitters
Page 4 • 6th ADC Summit San Diego, 2015
Alpha camera image of Thorium-227 droplet
Thorium-227 Manufacture from Actinium-227
b
 Primordial U-235 (half-life 700 million yrs)
21.8 y
decays via Th-231 and Pa-231 to Ac-227

α
Low abundance of natural occuring
Ra-223
Actinium-227

Commercial production of Ac-227 through
α
irradiation with neutrons of natural enriched
Radium-226
α
Ac-227
Th-227
18.7 d
11.4 d
*
Rn-219
3.96 s
Po-215
α
1.78 ms
Bi-211
2.14 m
Pb-211
36.1 m
α
Tl-207
4.77 m
*IFE = Institutt For Energiteknikk
Page 5 • 6th ADC Summit San Diego, 2015
Pb-207
b
(stable)
Xofigo manufacturing process adapted for
Thorium-227 production.
Xofigo & TTCs:
First in Class Alpha-Pharmaceuticals
Xofigo (Radium-223) acts as a calcium mimic1
 Targets bone metastases in prostate cancer patients
 Highly localized tumor cell killing
Bone marrow
Tumor
cells
Osteoblast
Alpha
particle
radiation
Newly
formed
bone
Osteoclast
Radium-223
deposition
1
Henriksen et al, JNM (2003, Vol 44)
However, Radium-223 is not suitable for targeting tumors outside the bone.
Thorium-227 can be complexed by chelates conjugated to targeting moieties such as
antibodies for delivery to tumor cells.
Page 6 • 6th ADC Summit San Diego, 2015
Mechanism of Action of Alpha-Pharmaceuticals
Alpha-particles are high energy,
heavy charged particles
223
88Ra
227
90Th
α
Alpha-particles have a short range
4
2He
High Linear Energy Transfer (LET)
Dose Administration
 No special shielding requirements
Alpha-particles, high LET, deposit their energy over a short distance (2-10 cell diameters).
High propensity for DNA double strand breaks.
Page 7 • 6th ADC Summit San Diego, 2015
Targeted Thorium Conjugates - TTCs
ADC
TTC
Cancer Cell
•
Internalisation required
•
Cross-fire /By-Stander effect not inherent
(adaptable through chemistry)
•
Mostly dependent on proliferative state
•
Development of resistance anticipated
Page 8 • 6th ADC Summit San Diego, 2015

Internalisation not a requirement

Cross-fire effect inherent
(independent of antigen heterogeneity)

Proliferative state independent = DNA DSBs

Mechanisms of resistance to alpha-particles so
far not reported
Targeted Thorium Conjugates (TTCs):
3 Key Components
1. Targeting moiety (e.g. antibody)
Lys
+
227Th
RT, 60 min
2. 3,2-HOPO-Chelator
Conjugate
3. Thorium-227
Lys
Chelator holds on to
thorium with several
”arms”, resulting in a
stable complex
TTC
The TTC platform is amenable to diverse targeting
moieties, including antibody scaffolds or peptides.
Page 9 • 6th ADC Summit San Diego, 2015
Uniqueness of Thorium-227
Distribution of 223Ra in patients
 Half-life of 18.7 days
 97.4% alpha emission
 Radium-223 is first daughter nuclide
Relative survival %
 No significant uptake in liver or kidney
Beta
Potent cell kill by
alpha emission
Alpha
99m
Activity (MBq/l)
see Supiot S et al Cancer 2002
Day 2
Baseline
Tc -MDP
Imaging
based on
223
Ra
Rapid clearance into gut (no liver, no mucositis)
Spares kidney- radiation dose low
Due to the physical properties of Thorium-227 (including MoA) which enable
proprietary manufacturing technologies, TTCs are commercial attractive.
Page 10 • 6th ADC Summit San Diego, 2015
Day 6
Case Study I:
CD33-TTC in Acute Myeloid Leukemia (AML)
Page 11 • 6th ADC Summit San Diego, 2015
Case Study I:
CD33-TTC to Target Acute Myeloid Leukemia (AML)
CD33: Naturally expressed on myeloid progenitor cells
with a restricted pattern in blood cells.
Lymphoid Tissue
Bone Marrow
Hem.
Stem Cell
Progenitor Cell
Myeloid Cells
Precursor Cell
Myeloblast
Monoblast
Megakaryoblast
CD33: Internalizing cell
surface receptor with
current unknown
function
Peripheral Blood
Tissue
Mature Cell
Myelocyte
Monocyte
Disease
Macrophage
% CD33 Surface Expression
AML
>85 – 90%
APL
~ 100%
ACL
~ 25% (bi-lineage)
CLL
 chronic phase
Extracellular Region
Griffin JD Leuk Res 1984 and Jilani I et al Am J Clin Pathol. 2002
Cytosolic
Region
ITIM (like) Motives
CD33 is a clinically validated target for the treatment of AML.
see Perez-Oliva AB Glycobiology 2009
Page 12 • 6th ADC Summit San Diego, 2015
Case Study I:
Biophysical Properties of CD33-TTC
Radiostability of CD33-TTC
ADC1 A, ADC1 CHANNEL A (RS\SEC_CAR 2015-07-02 14-39-46\1AC-0401.D)
ADC1 A, ADC1 CHANNEL A (RS\SEC_CAR 2015-07-02 14-39-46\1AA-0201.D)
Norm.
mAU
50
CD33-TTC
40
30
Overlay at 280nm at t=0h
and t=48h
Lintuzumab
20
CD33-TTC retains binding to target
A b s o rb a n c e (4 5 0 n m )
4
C D 3 3 A n tib o d y ; E C 5 0 = 0 .3 9 n M
0
C D 3 3 - T T C ; E C 5 0 = 0 .4 5 n M
3
0h
48h
10
2
2
Time
1
0h
24h
48h
0
1 0 -4
1 0 -2
10 0
4
6
8
10
12
14
Time (min)
Is o . C o n tr o l-T T C
10 2
HMW/Monomer
(280nm)
3.9%/96.1%
3.9%/96.1%
5.1%/94.9%
Radiochemical
Purity
(ITLC)
98.6%
99.8%
99.6%
10 4
Ig G ( n M )
CD33-TTC has biophysical properties similiar to the
parental antibody and is stable out to at least 48h.
Page 13 • 6th ADC Summit San Diego, 2015
Case Study I:
In Vitro Cell Cytotoxicity
CD33+/MDR-Negative
CD33+/MDR-Positive
(HL-60)
(KG-1)
200
200
M e d iu m
M e d iu m
150
C D 3 3 - T T C ( 2 k B q /m L )
C D 3 3 - T T C ( 2 0 k B q /m L )
100
50
0
Is o ty p e C o n tro l-T T C (1 0 k B q /m L )
V ia b ilit y ( % )
V ia b ilit y ( % )
Is o ty p e C o n tr o l T T C ( 2 0 k B q /m L )
150
C D 3 3 - T T C ( 5 k B q /m L )
C D 3 3 - T T C ( 1 0 k B q /m L )
100
50
0
0
2
4
6
8
0
D ay
2
4
6
8
D ay
Target-Negative
(Ramos)
300
M e d iu m
V ia b ilit y ( % )
C D 3 3 -T T C ( 5 k B q /m L )
200
CD33-TTC induces robust and specific cell kill on
target-positive cells independent of MDR-status.
100
0
0
2
4
D ay
Page 14 • 6th ADC Summit San Diego, 2015
6
Case Study I:
Mode of Action of CD33-TTC on HL-60 cells
DNA Double Strand Breaks
G2 Cell Cycle Arrest
CD33-TTC
γ-H2AX Detection
74%
Medium
Formation of Apoptotic Bodies
Adapted from CisBio
2%
Medium
CD33-TTC
CD33-TTC induces DNA double strand breaks, resulting in cell cycle arrest and ultimately
in cell death.
Page 15 • 6th ADC Summit San Diego, 2015
Case Study I:
Biodistribution of CD33-TTC in an HL-60 cell
Subcutaneous Model in Mice
Tumor uptake of CD33-TTC
based on Thorium-227 counts
2 4 h o u rs
4 days
20
7 days
10
% ID o f
227
T h p e r g ra m o rg a n
30
d
lo
sc
M
B
u
m
e
F
o
le
r
u
e
in
st
te
a
L
S
m
a
rg
ll
e
in
in
te
p
st
le
in
e
e
n
y
e
S
K
id
n
iv
L
T
u
m
o
e
r
r
0
Dosing
Cell inoculation (HL-60 sc)
Harvest/
counts
227Th
Harvest/
counts
227Th
Harvest/
counts
227Th
Study End
Day 7 (n=3)
Day -10
Day 0
Day 1 (n=3)
Day 4 (n=3)
Tumor uptake of the CD33-TTC is observed over the course of 7 days based
on accumulated Thorium-227.
Page 16 • 6th ADC Summit San Diego, 2015
Case Study I:
Efficacy of CD33-TTC in an HL-60 cell
Subcutaneous Model in Mice
Efficacy of CD33-TTC
in sc HL-60 Xenograft
Changes in Body Weight
140
3
Single Dose
Treatment at
TV = 100 mm3
1000
Body weight (%)
T u m o r V o lu m e ( m m )
1500
500
130
120
110
100
90
0
0
10
20
30
40
D a y s (p o s t tre a tm e n t)
50
0
10
20
V e h ic le
C D 3 3 C o n ju g a te
CD33 Conjugate
(7 0 0 k B q /k g )
C D 3 3 -T T C (7 0 0 k B q /k g )
40
Days (post treatment)
Vehicle
Is o ty p e C o n tr o l- T T C
30
Isotype Control-TTC (700 kBq/kg)
CD33-TTC (700 kBq/kg)
Administered as single-dose (2.7 pmol/kg Thorium-227) the CD33-TTC is both well
tolerated and induces significant tumor regression.
Page 17 • 6th ADC Summit San Diego, 2015
50
Case Study I:
Efficacy of CD33-TTC in an HL-60
Disseminated Model
Cell inoculation
5x106 cells (iv; HL-60)
Single-Dose
Treatment
2nd Dose
at 150 kBq/kg
Animals terminated at humane endpoint
Day 0
Day 14
Day 7
100
kBq/kg
V e h ic le
80
Vehicle
Iso. Ctrl.
Is o ty p e C trl.-T T C (3 0 0 k B q /k g )
60
C D 3 3 -T T C (2 x 1 5 0 k B q /k g )
S u r v iv a l ( % )
C D 3 3 C o n ju g a te
2nd Dose
150 kBq/kg
40
C D 3 3 - T T C (5 0 k B q /k g )
C D 3 3 -T T C (1 5 0 k B q /k g )
20
CD33TTC
300
2x150
50
150
300
pmol
MST
/kg (Mantel Cox)
1.2
2x0.58
0.19
0.58
1.2
55d (-)
57.5d (ns)
56d (ns)
n.d. (****)
90d (****)
116d (****)
n.d. (***)
C D 3 3 -T T C (3 0 0 k B q /k g )
0
0
50
100
150
S tu d y d a y
CD33-TTC demonstrated efficacy at dose levels as low as 0.19 pmol/kg Thorium-227 and a
statistically significant increase in median survival time.
Page 18 • 6th ADC Summit San Diego, 2015
Case Study II:
CD70-TTC in Renal Cell Carcinoma (RCC)
Page 19 • 6th ADC Summit San Diego, 2015
Case Study II:
CD70-TTC for Targeting Renal Cell Carcinoma (RCC)
Target Description
 CD70 is an internalizing single span-membrane
protein
 CD70 is a member of the TNF-SF and its expression
is transiently induced on B- and T-cells after antigen
stimulation
 CD70 expression is absent on most normal tissues
and vital organs
ccRCC; see Adam PJ et al; Br J Cancer 2006 Vol 95
High expression in B-cell malignancies and RCC reported.
Page 20 • 6th ADC Summit San Diego, 2015
Case Study II:
In Vitro Properties of CD70-TTC
M e d ia n F lu o r e s c e n c e In t e n s ity
Binding of CD70-TTC
to 786-O cells
Cell cytotoxicity of CD70-TTC
on 786-O cells
4000
D ay 6
C D 7 0 -T T C (2 0 k B q /m l)
3000
D ay 0
C D 7 0 -T T C (2 k B q /m l)
2000
C D 7 0 C o n ju g a te
1000
Is o ty p e C o n tr o l (2 0 k B q /m l)
0
1 0 -3
1 0 -2
1 0 -1
10 0
10 1
10 2
M e d iu m
Ig G (  g /m l)
0
C D 7 0 A n t ib o d y
C D 7 0 C o n ju g a te
E C 5 0 = 0 .1 1 µ g /m l
50
100
150
200
V ia b ilit y in %
E C 5 0 = 0 .1 2 µ g /m l
Is o t y p e C o n t r o l
CD70-TTC demonstrated specific binding and cell killing on target-positive cell lines.
Page 21 • 6th ADC Summit San Diego, 2015
Case Study II:
Biodistribution of CD70-TTC in a 786-O Cell
Subcutaneous Model in Mice
Uptake of CD70-TTC in 786-O tumors
based on Thorium-227 counts
150
C D 7 0 -T T C
Is o t y p e C o n t r o l- T T C
100
Day 7 post injection
50
10
5
Page 22 • 6th ADC Summit San Diego, 2015
M
u
m
sc
u
le
r
e
e
te
rg
a
L
F
st
in
st
In
e
In
ll
a
m
S
CD70-TTC demonstrated specific tumor uptake.
in
e
n
te
p
S
n
id
K
le
e
e
ys
r
iv
L
o
lo
B
o
m
u
T
e
d
r
0
u
% ID o f
227
T h p e r g ra m o rg a n
Autoradiography of 786-O tumor
slices after dosing with CD70-TTC
Case Study II:
In Vivo Efficacy of CD70-TTC in an 786-O
Subcutaneous Model in Mice
600
Vehicle
CD70 Conjugate
Iso. Ctrl.-TTC (500 kBq/kg)
CD70-TTC (50 kBq/kg)
CD70-TTC (100 kBq/kg)
CD70-TTC (300 kBq/kg)
400
CD70-TTC (500 kBq/kg)
1200
Tumor Volume (mm3)
Changes in Body Weight
1000
Single Dose
Treatment
800
200
Single Dose
Treatment
150
V e h ic le
B o d y W e ig h t ( % )
Efficacy of CD70-TTC
in sc 786-O Xenograft
C D 7 0 C o n ju g a te
Is o . C tr l.- T T C ( 5 0 0 k B q /k g )
125
C D 7 0 - T T C ( 5 0 k B q /k g )
C D 7 0 - T T C ( 1 0 0 k B q /k g )
C D 7 0 - T T C ( 3 0 0 k B q /k g )
C D 7 0 - T T C ( 5 0 0 k B q /k g )
100
0
0
20
40
60
80
75
Days
0
20
40
60
80
D ays
Vehicle
kBq/kg
pmol/kg
T/C
(One Way
Anova)
-
Iso.
Ctrl.
500
1.9
0.49
(****)
CD70-TTC
-
50
0.19
100
0.39
300
1.2
500
1.9
0.75
(ns)
0.28
(****)
0.09
(****)
0.09
(****)
0.03
(****)
CD70-TTC administered as a single dose > 0.19 pmol/kg Thorium-227 was well tolerated
and resulted in significant tumor growth inhibition.
Page 23 • 6th ADC Summit San Diego, 2015
Case Study III:
CD22-TTC for Targeting B-Cell Malignancies
Page 24 • 6th ADC Summit San Diego, 2015
Bayer Aims for Clinical PoC in Hematological
Cancers (NHL) targeting CD22
CD22:
 Transmembrane Siglec glycoprotein
 Modulates B-cell function, survival and apoptosis
 Internalizing and recycles to the cell surface
 Widely reported as not being a “shed antigen” ie no
circulating levels of CD22 can be detected plasma
Jellusova J et al Frontiers in Imm 2012
CD22-TTC:
Mode of action:
 Targeting by epratuzumab* followed by decay of the
alpha particle emitter thorium-227; inducing double strand
DNA breaks
Lead indication & upside potential
 Refractory CD22 NHL with focus DLBCL and FL
 Several tumor options based on CD22 expression; NHL
(>90%), ALL (~100%), CLL (90%), HCL (100%).
Page 25 • 6th ADC Summit San Diego, 2015
*supplied by Immunomedics Inc
CD22-TTC Demonstrates Potency in
Preclinical Models
Efficacy of CD22-TTC
in a disseminated model (Daudi)
V e h ic le
100
C D 2 2 -C o n ju g a te
Is o - C tr l- T T C ( 1 0 0 k B q /k g ;Q 1 4 D 3 )
S u r v iv a l ( % )
80
C D 2 2 - T T C ( 1 0 0 k B q /k g )
60
C D 2 2 -T T C ( 1 0 0 k B q /k g ;Q 1 4 D 3 )
****
C D 2 2 - T T C ( 3 0 0 k B q /k g )
***
Vehicle
CD22Conjugate
Iso. Ctrl.
40
CD22-TTC
20
0
0
20
40
60
kBq Th-227 pmol Th-227
MST
per kg
per kg
(Mantel Cox)
21d
-
-
23d
3x100
100
3x100
300
3x0.39
0.39
3x0.39
1.2
30d
35.5d
39.5d
39d
80
S tu d y D a y
Efficacy of CD22-TTC
in a sc xenograft model (Ramos)
100
V e h ic le
Is o . C tr l.- T T C ( 3 0 0 k B q /k g )
S u r v iv a l ( % )
80
C D 2 2 - T T C ( 1 0 0 k B q /k g )
60
C D 2 2 - T T C ( 3 0 0 k B q /k g )
Single Dose
40
20
0
0
20
40
60
S tu d y D a y
Page 26 • 6th ADC Summit San Diego, 2015
80
100
kBq Th-227 pmol Th-227
MST
per kg
per kg
(Mantel Cox)
Vehicle
45d (-)
Iso. Ctrl.
300
1.2
38.5d (n.s)
100
0.39
47d (n.s)
CD22-TTC
300
1.2
n.d. (**)
Summary
 Targeted Thorium Conjugates (TTCs): a robust technology platform for
targeted alpha-pharmaceuticals
 MoA based on induction of DNA double strand breaks
 TTCs have already demonstrated significant efficacy in multiple models of
cancer
 CD22-TTC, entering Clinical Phase I, targeting CD22 in hematological
malignancies
 CTA approved and FPFV is planned in 2015.
Page 27 • 6th ADC Summit San Diego, 2015
Acknowledgement
Thorium Conjugate Research
(Bayer/Norway)
TRG Oncology
(Bayer/Germany)
Global Project Team/
Technical Development Team
(CD22-TTC)
Immunomedics
Page 28 • 6th ADC Summit San Diego, 2015
Thank you!