date1 parp inhibition: a new approach to cancer therapy? dr. geert kolvenbag
TRANSCRIPT
Date 1
PARP Inhibition: A New Approach To Cancer Therapy?Dr. Geert Kolvenbag
Date 2
Potential Conflict of Interest
• Employee and Shareholder / 1988 -– AstraZeneca
PARP Inhibition:A New Therapeutic Approach?
Geert J.C.M. Kolvenbag MD PhDGeert J.C.M. Kolvenbag MD PhD
Global Product Vice PresidentGlobal Product Vice President
AstraZenecaAstraZeneca
Why is DNA repair a good target?
DNA repair defects lead to increased cancer susceptibility and increased sensitivity to DNA damaging agents
Targeting DNA Repair in Oncology
DNA damage occurs all the time in all cells
Inhibiting DNA repair in cancer cells that have impaired repair pathways leads to selective cell killing and an increased therapeutic ratio
Normal cells have multiple DNA repairpathways but some are lost in cancer cells
Inducing Synthetic Lethality in Cancer Cells
Pre-cancerous CellDNA damage leads
to continuous activation of pathway A
AB
Death
B
Cancer CellSelective pressure loss of pathway A,genetic instability,
reliance on pathway B
B
Normal Cell
Full complementof repair pathways
Pathway B inhibitor
Survival
AB
AB
ABAlternative DNA repair pathways available
Cancer Cells are Highly Susceptible
to DNA Repair Inhibition
Cancer cells
Undergo deregulated proliferation
less time for DNA repair than in normal cells
Grow under stress, which causes ongoing DNA damage
Have DNA repair defects
mutator phenotype
allow growth despite ongoing genome instability
Are reliant on the DNA repair pathways they still retain
Focus on DDR Pathways for SSBs/DSBs
Base Base excision excision
repairrepair
Single-Single-strand strand breaksbreaks(SSBs)(SSBs)
PARPPARP
Double-Double-strandstrandbreaksbreaks(DSBs)(DSBs)
RecombinationalRecombinationalrepairrepair
ATMATMBRCABRCA
DNA-PKDNA-PK
HRHR NHEJNHEJ
Type of damage:
Repairpathway:
Repairenzymes:
Bulky adducts
Insertions& deletions
O6-alkylguanine
Nucleotide-excision
repair
Mismatch repair
Directreversal
XP, poly-
merases
MSH2,MLH1
AGT
Survival
Normal cell
Repair by Homologous Recombination
No effective repair(No HR pathway)
Cell death
Cancer cell with HRD
Mechanisms of Action of Olaparib
SSBs increased by dacarbazine, temozolomide and topotecan
DSBs increased by platinums
Mechanism 1:
Tumor specific
killing by olaparib
PARP
Replicating cells
olaparib
Mechanism 2:Potentiation
Hypothesis
In situations where the DNA repair is compromised inhibition of PARP will lead to synthetic lethality of the cell
DNA repair factors deficient in functioning:
BRCA gene deficient in genotype or phenotype
Other Homologues Recombination Repair factors deficient in functioning (HRD) , eg ATM, MDC1, MRE11
In presence of DNA damaging agents
Chemotherapy
Radiotherapy
Olaparib: An oral inhibitor of
Poly (ADP-ribose) Polymerase (PARP)
N
N
O
N
O
N OF
IC50 on PARP-1 = 4.9 nM IC50 on PARP-2 ≈ 5nMIC50 on PARP-3 ≈ 50nMIC50 on Tankyrase >1M
• olaparib (AZD2281; KU-0059436)
• Favorable PK
• Good bioavailability across species
• Tumor PK -Significant levels at 24 hrs following single oral dose
Does the PARP inhibition result in therapeutic effects In vitro
In vivo
Clinical response
10 -9 10 -8 10 -7 10 -6 10 -5 10 -40-4
-3
-2
-1
0
conc (M)
BRCA2-/-
BRCA2+/+
BRCA2+/-
Increased Sensitivity of BRCA1-/- and BRCA2-/- Cells to PARP Inhibition
10 -9 10 -8 10 -7 10 -6 10 -5 10 -40-4
-3
-2
-1
0
conc (M)
BRCA1-/-
BRCA1+/+
BRCA1+/-
No difference in sensitivity between heterozygous and wild-type BRCA cells
Farmer et al. Nature 2005; 434:917-21
Targeted inhibition selective and less toxic therapy
BRCA 1 & 2 -/- ES Cells are Very Sensitive to PARP Inhibition
BRCA2 +/-
BRCA2 -/-
Wild type
Log surviving fraction
0-4
-3
-2
-1
0
PARP inhibitor concentration (M)10-9 10-8 10-7 10-6 10-5 10-4
Increased levels of chromosomal aberrations in PARP inhibitor
treated BRCA2 -/- cells
WT BRCA-/-
0
1
2
3
4
BRCA2-/- + PARPi
WT + PARPi
Mea
n n
um
ber
of
chro
ma
tid
aber
rati
on
s p
er c
ell
Chromatid breaks
Complex aberrations
Farmer et al. Nature 2005; 434:917-21
KU95 Cell Line Panel: Olaparib Sensitivity
HRD and Sensitive HR Proficient and Resistant
RAD51 DNA damage induced foci
Olaparib IC50 data by tumor type
HRD is Strongly Linked with Cancer
ATM Mre11
CHK2BRCA2
FANC
MDC1
Breast
Ovarian
H&N
NSCLC
GI, HCC
Pancreas
Paediatrics
BRCA1
BRCA2
BRCA1 ATM
Mre11
ATM Mre11
MDC1
Mre11
FANC
BRCA2BRCA1
BRCA
MDC1 ATM
TN Breast
BRCA
ATM /MRE11
Serous Ovarian
NSCLCHead & Neck CRCATM /MRE11 MDC1 MRE11
CFA Analysis of Breast Cancer Lines using Olaparib
0.001
0.01
0.1
1
10
1 2 3 4 5 6 7 8 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Ola
par
ib IC
50 L
OG
[µ
M]
Non-luminal / basal (n=7)
Non-luminal / post-EMT (n=11)
Luminal (n=7)
Non-luminal / basal (n=7)Non-luminal / basal (n=7)
Non-luminal / post-EMT (n=11)Non-luminal / post-EMT (n=11)
Luminal (n=7)Luminal (n=7)
25 cell lines from the Slamon breast cancer panel
Alan Lau; Richard Finn & Dennis Slamon
Response to Olaparib by HR Status
Triple Negative cell lines (n=14)
43.75
56.25
HRD (n=12)
75.00
25.00
ER-, PR -, Her2+ cell lines (n=11)
22.22
77.78
HR proficient (n=13)
0.00
100.00
%Sensitive (< 1µM) %Insensitive
%Sensitive (< 1µM) %Insensitive
%Sensitive (< 1µM) %Insensitive
%Sensitive (< 1µM) %Insensitive
Olaparib Inhibits Growth of HRD Tumors in vivo
MDA-MB-231(HR proficient)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 2 4 6 8 10 12 14 16 18 20
Time (days)
Mea
n re
lativ
e tu
mou
r vol
ume
Vehicle
AZD2281
MDA-MB-468(HRD)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Time (days)
Mea
n re
lativ
e tu
mou
r vol
ume
Vehicle
AZD2281
MDA-MB-231 (HR proficient) and MDA-MB-468 (HRD) triple-negative cells were implanted s.c. on the flank of female nude mice. At tumour volumes of 100-200mm3, mice were treated with vehicle or olaparib (100mg/kg) administered IP once daily (n=8 for each group). Data are presented as mean relative tumour volume (mean RTV) and error bars represent SEM.
MDA-MB-231(HR proficient)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 2 4 6 8 10 12 14 16 18 20
Time (days)
Mea
n re
lativ
e tu
mou
r vol
ume
Vehicle
AZD2281
MDA-MB-468(HRD)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Time (days)
Mea
n re
lativ
e tu
mou
r vol
ume
Vehicle
AZD2281
MDA-MB-231(HR proficient)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 2 4 6 8 10 12 14 16 18 20
Time (days)
Mea
n re
lativ
e tu
mou
r vol
ume
Vehicle
AZD2281
MDA-MB-231(HR proficient)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 2 4 6 8 10 12 14 16 18 20
Time (days)
Mea
n re
lativ
e tu
mou
r vol
ume
Vehicle
AZD2281
MDA-MB-468(HRD)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Time (days)
Mea
n re
lativ
e tu
mou
r vol
ume
Vehicle
AZD2281
MDA-MB-468(HRD)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28
Time (days)
Mea
n re
lativ
e tu
mou
r vol
ume
Vehicle
AZD2281
MDA-MB-231 (HR proficient) and MDA-MB-468 (HRD) triple-negative cells were implanted s.c. on the flank of female nude mice. At tumour volumes of 100-200mm3, mice were treated with vehicle or olaparib (100mg/kg) administered IP once daily (n=8 for each group). Data are presented as mean relative tumour volume (mean RTV) and error bars represent SEM.
Aaron Cranston (KuDOS) & Richard Finn (UCLA)
Relative Tumour Volumes
0
5
10
15
20
25
30
0 5 10 15 20 25 30
Days after treatment
RT
V
VehiclePARPi qdx28 i.p. 50mg/kg
Mean RTV day 28 = 15.3
Mean RTV day 28 = 1.20
BRCA2-deficient KO Mice
Olaparib in Spontaneous BRCA2-Deficient Tumors
From Targeted Therapy to the
Olaparib Phase I Study
Oral, small molecule PARP inhibitor
IC50 for PARP1 enzyme in the low nM range
Phase I trial began at RMH then NKI; later expanded to other centres
Escalation phase: All tumor types Primary objectives of safety and tolerability
Expansion phase: BRCA mutation carriers (HR deficient) especially ovarian cancer Further assessment of efficacy
Overall Recruitment
Escalation Phase (n=46)1,2
Various tumor types; BRCA carrier status not mandatory
10 dose level cohorts:
10mg daily given for 2 out of 3 weeks
600mg bid continuous dosing
11 BRCA carrier ovarian cancer
Expansion phase (n=52) at 200mg bid continuous2
Confirmed BRCA mutation carriers
39 ovarian cancer
1Fong et al. Proceedings of ASCO 20062Yap et al. Proceedings of ASCO 2007
DemographicsBRCA-Mutated Ovarian Cancer Subpopulation
Characteristics Number
BRCA1 / BRCA2 / Family history 41 / 8 / 1
Median age (range) 52 (37-80) yrs
ECOG PS 0-1 47
Median duration from diagnosis to treatment (range) 4.7 (0.5–16) yrs
Platinum status
Sensitive (PD > 6 months after platinum)
Resistant (PD ≤ 6 months after platinum)
Refractory (PD on platinum or on completion of platinum)
10
27
13
Median no. of prior systemic therapies (range) 3 (1-8)
Toxicities
first 60 patients, all tumor types)
Most toxicities were Grade 1-2 (≥95%)
Most common toxicities were: nausea 28%, vomiting 18%, dysgeusia 13%, anorexia 12%
fatigue 28%
Grade 3-4 toxicities were rare: myelosuppression (≤5%)
nausea and vomiting (2-3%)
CNS: dizziness or mood changes (2-3%)
Pattern of toxicity similar in BRCA mutation carriers
Dose Limiting Toxicities (DLT)
Dose (mg)/ Schedule
Tumour type DLT Outcome
400 bid continuous
Ovarian CaG3 low mood and
G3 fatigue
Resolved within 24 hours of drug discontinuation
Recurred with re-challenge
600 bid continuous
Mesothelioma G4 thrombocytopeniaResolved 2 weeks after drug
discontinuation
600 bid continuous
Breast Ca G3 somnolenceResolved within 24 hours of drug
discontinuation
G1 on lower dose
Maximum Tolerated Dose (MTD) = 400mg bid
TotalPlatinum sensitive
Platinum resistant
Platinum refractory
No. of evaluable patients 46 10 25 11
Responders by RECIST 13 (28%) 5 (50%) 8 (32%) 0 (0%)
Responders by GCIG CA125 18 (39%) 8 (80%) 8 (32%) 2 (18%)
Responders by either RECIST or GCIG criteria 21 (46%) 8 (80%) 11 (44%) 2 (18%)
SD (> 4 cycles) 6 (13%) 1 (10%) 4 (16%) 1 (9%)
Median duration of response in weeks (range) 24 (10-77) 23 (16-77) 24 (10-65) 26 (20-32)
Response to Olaparib by Platinum-Free Interval
0
6
12
18
24
CR/PR SD >4 months PD
Platinum Sensitivity Correlated
with Response to Olaparib
Pla
tin
um
-fre
e in
terv
al (
mo
nth
s)
Sensitive Resistant Refractory
23 mm
21.05.07
12 mm 6.8 mm
03.04.07
Breast BRCA?
Ovarian BRCA1-/-
6.5 mm 3 mm
Olaparib Resistance
Pre-clinical Over expression of pgp (olaparib is pgp substrate)
Reactivating BCRA mutation
Clinical Todate no evidence of PARP inhibitor resistence
Note: Platinum resistence has been shown due to reactivating BRCA mutation
Olaparib Overcoming Drug Resistance
Pre-clinical Overcome TMZ resistence
Potentiation of chemotherapy, e.g. TMZ
Clinical No data yet
AZD2281 is a potent inhibitor of PARP and has
impressive clinical activity in BRCA patients with breast
and ovarian cancer
The drug has additional potential to benefit a larger
group of patients with HRD tumors
Patient selection is key to the success of this project
and is a paradigm for personalized health care
The development of biomarkers and a diagnostic are
complex but pivotal to:
Delivery of the right drug, at the right dose to the right patient
Summary
Acknowledgements The patients and their families
Royal Marsden Hospital Janet Hanwell Dimitrios Magkos
Netherlands Cancer Institute Jana van der Sar Marja Voogel
Edinburgh Cancer Centre
UZ Brussel Oncologisch Centrum
International Hereditary Cancer Centre, Poland
Jan Lubinski
Cancer Research UK Institute of Cancer Research/
Breakthrough Breast Cancer Research UK Andrew Tutt Pei-Jun Wu Alan Ashworth
AstraZeneca John Stone Mark O’Connor Helen Swaisland Peter Mortimer Jim Carmichael Clinical teams
Theradex UK FECS/AACR/ASCO Methods in Clinical
Cancer Research Workshop, Flims, 2005