Transcript Patricia S. Steeg, Ph.D.

New Molecular Targets for Metastatic Breast Cancer
Patricia S. Steeg, Ph.D.
Director, Molecular Therapeutics Program
Chief, Women’s Cancers Section, Laboratory of Pathology
National Cancer Institute
Bethesda, MD
We tend to focus on ER and Her-2. There is “more” !
Many new therapeutics are entering clinical trial in other types
of cancer and should be tested in breast cancer
Examples of New Molecular Targets for Metastatic Breast Cancer
BRCA / PARP Inhibitors
AG-014699
Bone Metastases
Denosumab
ZD4054, Atrasentan
hPTH (1-34)
Lung Metastases
MPA
Brain Metastases
Her-2 directed agents
HDAC Inhibitors
Patupilone
Sunitinib
Examples of New Molecular Targets for Metastatic Breast Cancer
BRCA / PARP Inhibitors
AG-014699
Bone Metastases
Denosumab
ZD4054, Atrasentan
hPTH (1-34)
Lung Metastases
MPA
Brain Metastases
Her-2 directed agents
HDAC Inhibitors
Patupilone
Sunitinib
DNA Double Strand Breaks in Normal Cells
Normal DNA
Double strand break in the DNA
Accumulation of proteins at DNA break
ATM ATR
BRCA1
Proteins halt cell proliferation
Proteins also repair the break
BRCA2
Repaired DNA, the cell survives
Loss of BRCA proteins (deletion, mutation) results in a difference in the ability
to repair damaged DNA between normal and cancerous tissues.
Tumor formation after injection of ES cells into mice
Loss of BRCA protein, combined with loss of a DNA repair protein called
Poly (ADP-ribose) polymerase (PARP), combine to make the DNA damage
last longer and to kill the tumor cell.
Inhibitors of the DNA repair enzyme Poly (ADP-ribose) polymerase (PARP)
have activity in mice:
Normal cells, vehicle
Normal cells, PARP Inhibitor
BRCA- cells, vehicle
BRCA- cells, PARP Inhibitor
Nature 434:917, 2005
PARP Inhibitors will be tested clinically in BRCA-linked breast
cancer.
Possible combinations include radiation, temozolomide and
platinum based chemotherapy.
First in human phase I trial of the PARP inhibitor AG-014699 with temozolomide (TMZ) in patients (pts)
with advanced solid tumors
R. Plummer, M. Middleton, R. Wilson, C. Jones, J. Evans, L. Robson, H. Steinfeldt, R. Kaufman, S.
Reich and A. H. Calvert Northern Ctr for Cancer Treatment, Newcastle upon Tyne, United Kingdom;
Oncology Unit, Churchill Hosp, Oxford, United Kingdom; Dept of Oncology; Queens Univ - Belfast, Belfast,
United Kingdom; Dept of Medcl Oncology, Beatson Oncology Ctr, Glasgow, United Kingdom; Cancer
Research - UK, London, United Kingdom; Pfizer Global Research & Development, La Jolla, CA
3065
Background: AG-014699 inhibits poly(ADP-ribose) polymerase (PARP) is a key enzyme in DNA repair. AG014699 sensitizes cancer cells to DNA damaging drugs such as TMZ. AG-014699 is the first PARP inhibitor to
be evaluated in cancer patients. Methods: In part 1 of the study, pts with solid tumors received AG-014699 +
TMZ daily x 5 every 28 days. TMZ dose was half of standard (100 mg/m2 po) and AG-014699 (30 min
infusion) was escalated up to the PARP-inhibitory dose (PID) as determined by PARP activity in peripheral
blood lymphocytes (PBLs). We defined PID as maximal (at least >50%) reduction in PARP activity 24 hr after
AG-014699. In part 2, AG-014699 dose was fixed at PID and TMZ was escalated to maximum tolerated dose
or 200 mg/m2 in metastatic melanoma pts. Endpoints included safety, efficacy, PK and tumor PARP activity
(obligatory in part 2). Overall objective based on xenograft data was to achieve > 40% PARP inhibition in
tumor. Results: 27 pts enrolled, safety data available on first 18. In part 1, AG-014699 dose levels in 18 pts
were 1, 2, 4, 8 and 12 mg/m2. No dose-limiting toxicity (DLT) was observed. All related events were grade (gr)
1/2, except 1 case each of gr 3 infection, fatigue, low phosphate and lymphopenia. PID was 12 mg/m2 based
on 74 -97% inhibition of PBL PARP activity. PK evaluation for AG-014699 alone after 2 - 12 mg/m2 shows
mean terminal T = 7.4 - 11.7 hr, clearance = 25 L/hr, and linear dose proportionality for AUC and Cmax. AG014699 did not affect TMZ PK compared to historical data. Two durable partial responses (15+, 9+ mo)
occurred (GIST, melanoma). In part 2, no DLT was seen in 9 pts up to 200 mg/m2 TMZ. Median tumor PARP
inhibition at 5 hours was 90% (range 50 - 98%). Conclusions: Doses up to 12 mg/m2 AG-014699 and 200
mg/m2 TMZ are safe and significantly inhibit PBL and tumor PARP. One further dose level (AG-014699 18
mg/m2, TMZ 200 mg/m2) will be tested to maximize tumor PARP inhibition.
J. CLIN. ONCOL. 23 (16): 208S-208S
Part 1 Suppl. S, JUN 1 2005
Examples of New Molecular Targets for Metastatic Breast Cancer
BRCA / PARP Inhibitors
AG-014699
Bone Metastases
Denosumab
ZD4054, Atrasentan
hPTH (1-34)
Lung Metastases
MPA
Brain Metastases
Her-2 directed agents
HDAC Inhibitors
Patupilone
Sunitinib
Types of Bone Metastases
Osteoclastic
Osteoblastic
The Osteoclastic “Vicious Cycle” Has Become Complex
Nature Medicine 12:895, 2006
Rank-L activates osteoclasts, which
cause bone destruction.
Denosumab is a monoclonal antibody
To Rank-L (Amgen)
A Phase I clinical trial has been conducted
to determine if Denosumab reduces
bone turnover in breast cancer patients
with bone mets.
Eur. J. Cancer Suppl. 4: 63, 2004
EORTC-NCI-AACR Symposium on Molecular Targets
And Cancer Therapeutics Poster
Bone Resorption
Pamidronate
Denosumab
mAb to RANK-L
Clin. Cancer Res. 12:1221, 2006
Denosumab Safety, Pharmacokinetics (PK), and Pharmacodynamics (PD) in a Phase 1
Study of Japanese Women With Breast Cancer-Related Bone Metastasis
Hironobu Minami, MD;1 Kouichi Kitagawa,1 MD; Kan Yonemori, MD;2 Yasuhiro Fujiwara, MD, PhD;2
Hirofumi Fujii, MD, PhD;3 Tatsuhiro Arai, MD;3 Masayuki Ohkura;4 Graham Jang, PhD;5 Tomoko Ohtsu,
MD, PhD4
1National Cancer Center Hospital East, Kashiwa, Japan; 2National Cancer Center Hospital, Tokyo,
Japan; 3Tochigi Cancer Center, Utsunomiya, Japan; 4Amgen Ltd., Tokyo Japan; 5Amgen Inc.,
Thousand Oaks, CA USA
Eur. J. Cancer Suppl. 4: 63, 2004
EORTC-NCI-AACR Symposium on Molecular Targets
And Cancer Therapeutics Poster
Eur. J. Cancer Suppl. 4: 63, 2004
EORTC-NCI-AACR Symposium on Molecular Targets
And Cancer Therapeutics Poster
Serum C-telopeptide
Eur. J. Cancer Suppl. 4: 63, 2004
EORTC-NCI-AACR Symposium on Molecular Targets
And Cancer Therapeutics Poster
Decreases in Bone
Turnover Markers:
Urine N-telopeptide
(corrected for creatinine)
Conclusions from Poster
Well tolerated
Adverse event profile similar to that seen in patients with advanced cancer
Rapid (within 24h), substantial (>60%) and sustained (12 w) suppression
of bone turnover markers
Phase 3 trials for the prevention and treatment of skeletal related events
are in progress.
Eur. J. Cancer Suppl. 4: 63, 2004
EORTC-NCI-AACR Symposium on Molecular Targets
And Cancer Therapeutics Poster
Preclinical and Clinical Leads to Osteoblast Activation
ET-1
ET-A
Tumors secrete Endothelin-1 (ET-1) which
activates osteoblasts. It binds to
a receptor on osteoblasts called endothelinA (ET-A).
ZD4054 is an ET-1 antagonist.
Atrasentan is a ET-A antagonist
hPTH1-34 is a PTHrP antagonist that has been in a Phase I
trial for osteoporosis
Osteoporosis Int. 17:1532, 2006
E.D. Williams et al. Poster from Abstract 36
Eur. J. Cancer Suppl. 4:15, 2006
18th EORTC-NCI-AACR Symposium on Molecular Targets
and Cancer Therapeutics
Examples of New Molecular Targets for Metastatic Breast Cancer
BRCA / PARP Inhibitors
AG-014699
Bone Metastases
Denosumab
ZD4054, Atrasentan
hPTH (1-34)
Lung Metastases
MPA
Brain Metastases
Her-2 directed agents
HDAC Inhibitors
Patupilone
Sunitinib
Nm23 Metastasis Suppressor Gene
Tumor Cell
Line
Control
Metastasis
Suppressor
Gene
In tissue culture:
Less motility
Less invasion
Less colonization
Differentiation
Equal proliferation
Can Nm23 Expression be Restored to Micrometastatic
Breast Cancer Cells in the Lungs?
Medroxyprogesterone acetate (MPA) is traditionally a progestin;
However, it also interacts with the Glucocorticoid receptor (GR) and
can therefore have effects in PR-negative cancer cells.
We have found that high dose MPA elevates the Nm23 metastasis
Suppressor gene expression of PR-negative, metastatic breast
Cancer cells through the GR.
CSS
FCS
-Nm23-H1
-Nm23-H2
-AlphaTubulin
0
0.001
0.01
0.1
1
10
100
0
0.001
0.01
0.1
1
10
Clin. Cancer Res. 8:3763, 2003
MPA Clinical History
CH3
C=O
O
C
Used in low doses as slow-release
contraceptive, with estrogen in
CH3
HRT.
O
O
CH3
Used previously at high doses as a progesterone
receptor (PR) agonist for treatment of advanced
breast and endometrial cancers.
Some responses observed, but optimal dose and schedule never
identified. Conflicting reports on correlation of responses and
PR expression.
Both stimulatory and inhibitory effects in mouse models
Experimental Design: Will MPA Inhibit Metastatic
Colonization? MDA-MB-231T Cells: ER-, PR-, GR+
Week 4 - Micrometastases detectable in the lung parenchyma
J. Nat’l. Cancer Inst. 97:632, 2005
Effects of MPA on Pulmonary Metastasis of MDA-MB-231 cells
Experiment:
Treatment:
Mean Metastases
per mouse:
1
Control
32.3
Percent reduction:
Mean Metastases
> 3mm:
3.2
Reduction from Control:
2 mg
21.7
2
4mg
15.6
Control
33.4
33% 52%
0.6
5x
0.9
3x
0.5 mg
1 mg
2 mg
22.2
12.6
14.5
34%
2.0
0.8
2x
62%
0.5
4x
57%
0.5
4x
Other effects:
• Weight gain
• No abnormalities in mammary fat pad histology
• No change in bone density
• Increased Nm23 expression in pulmonary metastases
J. Nat’l. Cancer Inst. 97:632, 2005
MPA Revisited:
A Phase II Study of Anti-Metastatic, Anti-Angiogenic Therapy
in Postmenopausal Patients with Hormone Receptor Negative Breast Cancer
Principal Investigator:
Kathy D. Miller, M.D.
Indiana University Medical Center
535 Barnhill Drive, RT-473
Indianapolis, IN 46202
R Cohort 1
E
G
I
S
T
E Cohort 2
R
MPA 1000 mg/d
Day 10-14 trough
[MPA] > 50 ng/ml
Day 10-14 trough
[MPA] < 50 ng/ml
MPA 1000 mg/d
+ ldoCM
Day 10-14 trough
[MPA] > 50 ng/ml
Day 10-14 trough
[MPA] < 50 ng/ml
MPA 1000 mg/d
MPA 1500 mg/d
MPA 1000 mg/d
+ ldoCM
MPA 1500 mg/d
+ ldoCM
CR, PR,
Continue
SD
PD
Off study
CR, PR,
Continue
SD
PD
Off study
Examples of New Molecular Targets for Metastatic Breast Cancer
BRCA / PARP Inhibitors
AG-014699
Bone Metastases
Denosumab
ZD4054, Atrasentan
hPTH (1-34)
Lung Metastases
MPA
Brain Metastases
Her-2 directed agents
HDAC Inhibitors
Patupilone
Sunitinib
Brain metastases develop in 15% of metastatic breast cancer
patients.
Brain metastases appear to
be increasing as a sanctuary
site as systemic control
improves, particularly for
patients with Her-2
amplified tumors.
Many patients develop brain
metastases when they are
responding to treatment
The median survival time is dismal. One year survival is estimated
at 20%.
Current treatments include gamma knife, whole brain radiation
therapy, chemotherapy, steroids and surgery
A Unique Microenvironment
The blood:brain barrier (BBB) and
brain microenvironment are
hypothesized to provide distinct
molecular pathways underlying
metastasis.
The brain microenvironment also
contains neurons, astrocytes,
microglia.
Role for edema?
Once tumor cells penetrate the BBB, a blood:tumor barrier (BTB) is formed.
Almost nothing is known about the patency of the BTB to metastases.
Am. J. Pathol. 167:913, 2005
Blood-Brain Barrier Permeability of Ten Common
Chemotherapeutic Drugs
-In relation to drug lipid solubility as measured by the octanol/water partition
coefficient. The line and solid squares illustrate the permeability relation for
solutes that cross the blood-brain barrier by simple passive diffusion.
Compounds with a Log Permeability value less than -3 would
be classified as having POOR blood-brain barrier permeability
Courtesy of Drs. Paul Lockman and Quentin Smith
Why Her-2 Status ?
Of 122 women receiving trastuzumab +/- chemotherapy,
symptomatic CNS metastases were identified in 34%.
Fifty percent of the patients were responding to therapy, or had
stable disease when they developed CNS metastases.
Cancer 97: 2972, 2003
Of 93 metastatic patients receiving trastuzumab, brain metastases
occurred in 25% over a median followup time of 10.8 months. 78%
of patients with brain metastases had stable disease at other sites. The
CNS was the first site of symptomatic progression in 82% of patients,
and the only site of disease progression at that time in 69% of patients.
Br. J. Cancer 91:639, 2004
Why are breast cancer patients with Her-2+ tumors
developing brain metastases?
• Living longer
• Trastuzumab poorly penetrates the BBB (BTB)
• Her-2 promotes brain metastasis
A Perfect Storm: Her-2
Overexpression Promotes Brain Mets
MDA-MB-231 Brain Seeking:
Vector
Low High
Her-2 Her-2
Total Her-2
Tubulin
Clone:
Mean Large Brain Mets (95%CI)
Vector 1
Vector 2
P:
5.1 (3.7 - 6.6)
2.9 (2.0 – 3.8)
Low Her-2 1
Low Her-2 2
11.3 (8.3 – 14.4)
16.6 (15.1 – 18.1)
High Her-2 1
High Her-2 2
10.9 (8.9 – 12.9)
14.0 (11.6 – 16.4)
0.0001
0.0001
Palmieri et al.
Cancer Res. Under revision.
Transfection of Her-2 elevated the number of “large”
metastases three fold. The data indicate a functional contribution
of Her-2 overexpression to the development of large
(i.e., clinically detectable) brain metastases.
The data confirm the need to develop Her-2 inhibitors with
brain permeability. This may require a new paradigm for lead
compound selection.
Palmieri et al. Cancer Res. Under revision.
Therapeutic Approaches to Her-2+ Brain Metastases
Trastuzumab (Herceptin, Genentech)
Humanized recombinant monoclonal antibody to Her-2
Efficacy in combination with chemotherapy in metastatic and
adjuvant settings
Relapses in the brain
CSF concentrations are 300 fold lower than blood levels
Lapatinib (Tykerb, GSK)
Small molecule EGFR-Her-2 heterodimerization inhibitor
Efficacy in Herceptin-resistant metastatic breast cancer
Fewer relapses in the brain
Limited efficacy in Phase I trial against established brain mets
JNJ26483327 (J&J)
Small molecule inhibitor of EGFR, Her-2 and Src
Phase I trial open
Brain permeability claimed
Perera et al. Eur. J. Cancer Suppl. 4: 178, 2004
EORTC-NCI-AACR Symposium on Molecular Targets
And Cancer Therapeutics Poster
Other Drugs with Potential Brain Permeability
HDAC Inhibitors
Histone deactylase inhibitors
Restores expression of “suppressor genes”
Clinical trial and approved
Patupilone
Microtubule active
Sunitinib (SU11248)
VEGFR, PDGFR, KIT, RET, CSF-1R, FLT3.
Sunitinib concentrations in
the brain in mice and monkeys
Patyna et al. Eur. J. Cancer Suppl.
4: 21, 2004
EORTC-NCI-AACR Symposium on
Molecular Targets
and Cancer Therapeutics Poster