Date1 PARP Inhibition: A New Approach To Cancer Therapy? Dr. Geert Kolvenbag.

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




Olaparib Inhibits Growth of HRD Tumors in vivo

MDA-MB-231(HR proficient)

0.0

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1.0

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3.5

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0 2 4 6 8 10 12 14 16 18 20

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n re

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AZD2281

MDA-MB-468(HRD)

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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.


0.0

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MDA-MB-468(HRD)

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AZD2281


0.0

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AZD2281


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n re

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e tu

mou

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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)

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n re

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mou

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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

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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

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

Date1 PARP Inhibition: A New Approach To Cancer Therapy? Dr. Geert Kolvenbag.

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