patricia s. steeg, ph.d. director, molecular therapeutics program chief, women’s cancers section,...

Patricia S. Steeg, Ph.D.Director, Molecular Therapeutics Program

Chief, Women’s Cancers Section, Laboratory of PathologyNational Cancer Institute

Bethesda, MD

New Molecular Targets for Metastatic Breast Cancer

Many new therapeutics are entering clinical trial in other types of cancer and should be tested in breast cancer

We tend to focus on ER and Her-2. There is “more” !

Examples of New Molecular Targets for Metastatic Breast Cancer

BRCA / PARP InhibitorsAG-014699

Bone MetastasesDenosumabZD4054, AtrasentanhPTH (1-34)

Lung MetastasesMPA

Brain MetastasesHer-2 directed agentsHDAC InhibitorsPatupiloneSunitinib

Normal DNA

Double strand break in the DNA

BRCA1

BRCA2

ATMATR

Accumulation of proteins at DNA break

Proteins halt cell proliferationProteins also repair the break

Repaired DNA, the cell survives

DNA Double Strand Breaks in Normal Cells

Loss of BRCA proteins (deletion, mutation) results in a difference in the ability to repair damaged DNA between normal and cancerous tissues.

Loss of BRCA protein, combined with loss of a DNA repair protein calledPoly (ADP-ribose) polymerase (PARP), combine to make the DNA damagelast longer and to kill the tumor cell.

Inhibitors of the DNA repair enzyme Poly (ADP-ribose) polymerase (PARP)have activity in mice:

Normal cells, vehicleNormal cells, PARP Inhibitor

BRCA- cells, vehicle

BRCA- cells, PARP Inhibitor

Nature 434:917, 2005

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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. AG-014699 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. AG-014699 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




Lung MetastasesMPA


Osteoclastic

Osteoblastic

Types of Bone Metastases

Nature Medicine 12:895, 2006

The Osteoclastic “Vicious Cycle” Has Become Complex

Rank-L activates osteoclasts, whichcause bone destruction.

Denosumab is a monoclonal antibodyTo Rank-L (Amgen)

A Phase I clinical trial has been conductedto determine if Denosumab reducesbone turnover in breast cancer patientswith bone mets.

Eur. J. Cancer Suppl. 4: 63, 2004EORTC-NCI-AACR Symposium on Molecular TargetsAnd Cancer Therapeutics Poster

Clin. Cancer Res. 12:1221, 2006

Pamidronate

DenosumabBon

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mAb to RANK-L


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

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Decreases in BoneTurnover Markers:

Urine N-telopeptide(corrected for creatinine)

Serum C-telopeptide

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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) suppressionof bone turnover markers

Phase 3 trials for the prevention and treatment of skeletal related eventsare in progress.


Preclinical and Clinical Leads to Osteoblast Activation

Tumors secrete Endothelin-1 (ET-1) which activates osteoblasts. It binds to a receptor on osteoblasts called endothelin-A (ET-A).ZD4054 is an ET-1 antagonist.

E.D. Williams et al. Poster from Abstract 36Eur. J. Cancer Suppl. 4:15, 200618th EORTC-NCI-AACR Symposium on Molecular Targetsand Cancer Therapeutics

ET-A

ET-1

Atrasentan is a ET-A antagonist

hPTH1-34 is a PTHrP antagonist that has been in a Phase Itrial for osteoporosis

Osteoporosis Int. 17:1532, 2006




Lung MetastasesMPA


Nm23 Metastasis Suppressor Gene

Tumor CellLine

Control Metastasis SuppressorGene

In tissue culture: Less motility Less invasion Less colonization Differentiation Equal proliferation

CSS FCS-Nm23-H1

-Nm23-H2

-Alpha-Tubulin

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

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 metastasisSuppressor gene expression of PR-negative, metastatic breastCancer cells through the GR.

Can Nm23 Expression be Restored to MicrometastaticBreast Cancer Cells in the Lungs?

MPA Clinical History

Used in low doses as slow-release contraceptive, with estrogen in HRT.

CH3

C=O

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Some responses observed, but optimal dose and schedule never identified. Conflicting reports on correlation of responses and PR expression.

Used previously at high doses as a progesteronereceptor (PR) agonist for treatment of advancedbreast and endometrial cancers.

Both stimulatory and inhibitory effects in mouse models

Week 4 - Micrometastases detectable in the lung parenchyma

Experimental Design: Will MPA Inhibit Metastatic Colonization? MDA-MB-231T Cells: ER-, PR-, GR+

J. Nat’l. Cancer Inst. 97:632, 2005

Experiment:

Treatment:

1 2

Control 2 mg 4mg Control 0.5 mg 1 mg 2 mg

32.3 21.7 15.6 33.4 22.2 12.6 14.5Mean Metastases per mouse:

Percent reduction: 33% 52% 34% 62% 57%

Effects of MPA on Pulmonary Metastasis of MDA-MB-231 cells

J. Nat’l. Cancer Inst. 97:632, 2005

Other effects:• Weight gain• No abnormalities in mammary fat pad histology• No change in bone density• Increased Nm23 expression in pulmonary metastases

Mean Metastases> 3mm: 3.2 0.6 0.9 2.0 0.8 0.5 0.5Reduction from Control: 5x 3x 2x 4x 4x

Principal Investigator:Kathy D. Miller, M.D.Indiana University Medical Center535 Barnhill Drive, RT-473Indianapolis, IN 46202

MPA Revisited: A Phase II Study of Anti-Metastatic, Anti-Angiogenic Therapy

in Postmenopausal Patients with Hormone Receptor Negative Breast Cancer

PD

CR, PR, SD

Day 10-14 trough [MPA] < 50 ng/ml

Day 10-14 trough [MPA] > 50 ng/mlCohort 2

CR, PR, SD

Day 10-14 trough [MPA] > 50 ng/ml

Day 10-14 trough [MPA] < 50 ng/ml

Cohort 1REGISTER

MPA 1000 mg/d

Off study

ContinueMPA 1000 mg/d

MPA 1500 mg/d PD

MPA 1000 mg/d + ldoCM



Continue

Off study




Lung MetastasesMPA


Current treatments include gamma knife, whole brain radiation therapy, chemotherapy, steroids and surgery

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%.

Am. J. Pathol. 167:913, 2005

The blood:brain barrier (BBB) and brain microenvironment are hypothesized to provide distinct molecular pathways underlying metastasis.

The brain microenvironment alsocontains 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.

A Unique Microenvironment

Blood-Brain Barrier Permeability of Ten Common Chemotherapeutic Drugs

Compounds with a Log Permeability value less than -3 would be classified as having POOR blood-brain barrier permeability

-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.

Courtesy of Drs. Paul Lockman and Quentin Smith

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

Why Her-2 Status ?

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. TheCNS 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+ tumorsdeveloping brain metastases?

• Living longer

• Trastuzumab poorly penetrates the BBB (BTB)

• Her-2 promotes brain metastasis

Tubulin

Vector Low Her-2

HighHer-2

Total Her-2

MDA-MB-231 Brain Seeking:

Palmieri et al. Cancer Res. Under revision.

Clone: Mean Large Brain Mets (95%CI) P:

Vector 1 5.1 (3.7 - 6.6)Vector 2 2.9 (2.0 – 3.8)

Low Her-2 1 11.3 (8.3 – 14.4)Low Her-2 2 16.6 (15.1 – 18.1) 0.0001

High Her-2 1 10.9 (8.9 – 12.9)High Her-2 2 14.0 (11.6 – 16.4) 0.0001

A Perfect Storm: Her-2 Overexpression Promotes Brain Mets

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 withbrain permeability. This may require a new paradigm for leadcompound selection.

Palmieri et al. Cancer Res. Under revision.

Therapeutic Approaches to Her-2+ Brain Metastases

Trastuzumab (Herceptin, Genentech)Humanized recombinant monoclonal antibody to Her-2Efficacy in combination with chemotherapy in metastatic and

adjuvant settingsRelapses in the brainCSF concentrations are 300 fold lower than blood levels

Lapatinib (Tykerb, GSK)Small molecule EGFR-Her-2 heterodimerization inhibitorEfficacy in Herceptin-resistant metastatic breast cancer

Fewer relapses in the brainLimited efficacy in Phase I trial against established brain mets

JNJ26483327 (J&J)Small molecule inhibitor of EGFR, Her-2 and SrcPhase I trial openBrain permeability claimed

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Other Drugs with Potential Brain Permeability

HDAC InhibitorsHistone deactylase inhibitorsRestores expression of “suppressor genes”Clinical trial and approved

PatupiloneMicrotubule active

Sunitinib (SU11248)VEGFR, PDGFR, KIT, RET, CSF-1R, FLT3.

Patyna et al. Eur. J. Cancer Suppl. 4: 21, 2004EORTC-NCI-AACR Symposium on Molecular Targetsand Cancer Therapeutics Poster

Sunitinib concentrations inthe brain in mice and monkeys

patricia s. steeg, ph.d. director, molecular therapeutics program chief, women’s cancers section,...

Documents

cancer cells

parp inhibitor ag

parp activity

parp inhibitor brca

metastatic breast cancer

cancer patients

damaged dna

parp inhibitor nature