The problem of the BBB
The Blood-Brain Barrier limits delivery of
chemotherapy and other therapeutics to the
CNS
Edward Neuwelt, MD
Advanced Topics in Cancer Biology
Oregon Health & Science University
May 28, 2009
Cerebral Circulation
675 km of veins, arteries, and capillaries
BBB consortium clinical
research
1. Increase chemotherapy delivery and efficacy in
brain tumors
Example: PCNSL
2. Decrease chemotherapy side effects
Example: ototoxicity
3. Imaging vascular targeted therapies with iron
oxide nanoparticles:
Is “less” better?
Treatment of Patients with Newly
Diagnosed PCNSL:
BBBD Consortium Results
Introduction to PCNSL
• An aggressive non-Hodgkin’s lymphoma,
usually B-cell origin
• Diffuse CNS disease; may involve the
brain, spinal cord, leptomeninges and eyes
at presentation
• Represents approx. 4% of intracranial
neoplasms
Treatment of PCNSL patients
• The optimal treatment is unknown
• HD Methotrexate (MTX) widely accepted as the most
effective chemotherapy
• Combined-modality therapy (HD MTX and WBRT) has
improved response rates, PFS and OS
• However, combined therapy is associated with a high
incidence of delayed neurocognitive toxicity, especially in
patients > 60 years
Introduction to BBBD
PCNSL lesion
(leaky BBB)
PCNSL lesion after
BBBD
(temporary opening of
brain around tumor)
Neuropsychological Outcome in Primary
CNS Lymphoma Patients
Multi-Center BBBD Study
Eligibility Criteria:
• BBBD treatment (MTX-based) within 90
days of diagnosis
• No prior WBRT
• No evidence of systemic lymphoma at
diagnosis
• HIV-1 negative
J Clin Oncol in press 2009
Patient characteristics
• N = 149 (78 Female/71 Male)
• Disease site: CNS (131 pts, 88%),
CNS and IO (15 pts), intra-ocular only (3 pts)
• CSF cytology: Neg (96 pts, 64%), atypical (14
pts), Pos (11 pts), Unknown (28 pts)
J Clin Oncol in press 2009
Outcome
• Overall response rate: 81.9%
(57.8% CR; 24.2% PR)
• Median OS: 3.1 yrs
(41% est. at 5 yrs; 25% at 8.5 yrs)
J Clin Oncol in press 2009
J Clin Oncol in press
Efficacy and MRI of rituximab
and methotrexate treatment in
a nude rat model of CNS
lymphoma
Neuro-Oncology. Epub ahead of print.
January 21, 2009
MRI and histology of the rat CNS
lymphoma model
In vitro toxicity of methotrexate
MTX was toxic in MC116 human B-lymphoma
at low doses in vitro
Efficacy of tumor treatment
Rituxan reduced rat CNS lymphoma tumor volume on MRI
MTX blocked tumor growth
Combination therapy was NOT effective
Does IV methotrexate decrease
response to IV rituxan by restoring
the BBB?
Q: Does Rituxan cross the BBB?
A: Yes and No
Summary
• BBBD chemotherapy can be conducted with acceptable
toxicity, however the treatment is complex and should be
undertaken only by trained teams
• Results with BBBD/IA MTX demonstrate comparable if not
superior outcomes (durable response rates, PFS, OS) to HD
IV MTX as well as to combination MTX and WBRT without
the neurocognitive sequelae of WBRT
• BBBD provides the opportunity to deliver effective
monoclonal antibody/chemotherapy regimens and other
novel agents to the CNS
In press, J Clin Oncol 2009
Cisplatin ototoxicity
• Overall incidence cisplatin
ototoxicity: 50-70%
• High frequency hearing
loss initially, progresses
with continued
treatment
• Unable predict hearing loss
based on dose or plasma
levels of
platinum
Blakely 1993
Treatment Dilemma
• Ototoxicity is dose-limiting
• Reducing the cisplatin dose stabilizes
hearing loss
• However, dose reductions may affect
efficacy of treatment
• Need strategies that can reduce/prevent
hearing loss without interfering with
chemotherapy
Patients Received Carboplatin, No STS
Maximum AC Cochlear Potential
STS Otoprotection
Carboplatin in the Guinea Pig
500
400
300
200
100
0
STS
2 hrs
STS
4 hrs
STS
8 hrs
STS
24 hrs
saline
Problems with Chemoprotection
Potential to reduce the
anti-tumor activity of
chemotherapy
Anti-tumor Efficacy in the Presence of
Chemoprotection
Tumor volumes were assessed 6 days after nude rats with
intracerebral tumors were treated with or without BBBD
chemotherapy alone or in combination with thiols NAC and/or
STS. Bar graph shows tumor volumes in n = 8 per group.
Tumor volume (mm3)
Anti-tumor Efficacy in the Presence of
Chemoprotection
30
20
TREATMENT GROUPS
1: Tri-drug BBBD
2: Tri-drug + STS
3: NAC + Tri-drug
4: NAC+ Tri-drug +STS
5: Untreated
10
0
1
2
3
4
5
Treatment Group
Bar graph shows tumor volumes in n = 8 per group.
Do Thiols Protect Tumor?
Not if separated from chemo
in time and space
Metastatic Ovarian
Patient Received
Carboplatin + STS
STS Otoprotection in Adults
Historical patients, no STS (n = 19)
STS 2 hr after carboplatin (n = 24)
STS 4 hr after carboplatin (n = 17)
Hearing loss (dB)
50
40
4&8 kHz
30
20
10
0
1
2
3
4
5
6
7
Treatment with Carboplatin + BBBD
Neuwelt et al
Chemoprotection may be valuable in
the clinical setting if chemotherapy and
chemoprotectant can be physically or
temporally separated.
ACCL0431
A Randomized Phase III Study of Sodium
Thiosulfate for the Prevention of Cisplatin-induced
Ototoxicity in Children
SIOPEL 6
A Randomized Phase III Trial of the Efficacy of
STS in Reducing Ototoxicity in Patients Receiving
Cisplatin Chemotherapy for Standard Risk
Hepatoblastoma
Iron oxide nanoparticles
as MRI contrast agents
Iron oxide nanoparticles

Iron oxide core




Coated with dextran or
other carbohydrate.


Molecular Model: Combidex®
MRI
Iron histochemistry
EM
reduces toxicity
alters plasma half life
OHSU experiences with
• Iron oxide nanoparticles
– Superparamagnetic Iron Oxide (SPIO)
– Feridex®
– Ultrasmall SPIO (USPIO)
– Combidex® (ferumoxtran-10)
– Ferumoxytol
Imaging inflammatory cells with
USPIOs
• Iron oxide nanoparticles are taken up by
inflammatory cells (B-cells, dedritic cells,
macrophages)
• Also taken up by activated glial cells in
and around CNS tumors
GBM
Gadolinium vs. Ferumoxtran-10
Presentation number: 10
MAGNETIC RESONANCE IMAGING USING FERUMOXYTOL
AND GADOTERIDOL IN PATIENTS WITH CENTRAL NERVOUS
SYSTEM INFLAMMATORY DISEASES: PRELIMINARY RESULTS
• Dósa E, Hamilton BE, Njus JM, Haluska M, Varallyay CG,
• Rooney WD, Nesbit G, Muldoon L, Neuwelt E
Departments of Neurology and Neuroradiology, AIRC
Oregon Health & Science University, Portland, Oregon, USA
May 18, 2009
Benign brain tumor - meningioma
Baseline - SWI & T1-w
GBCA
Ferumoxytol
(15 minutes)
Ferumoxytol
(24 hours)
CNS vascular malformation - telangiectasia & cavernoma
Baseline - SWI & T1-w
GBCA
Ferumoxytol
(15 minutes)
Ferumoxytol
(24 hours)
Gd vs. USPIO for imaging
9/6/03
T1
9/6/03
T1 Gadolinium
9/16/03
T1 Ferumoxtran-10
12/15/03
T1 Gadolinium
Gd vs. USPIO for imaging
10/14/03
10/14/03
Coronal
T1
T1 Gadolinium
10/20/03
2/4/04
Coronal
T1 Ferumoxtran-10
T1 Gadolinium
Demyelinating disease
Baseline - T2w
GBCA
Ferumoxytol
(15 minutes)
Ferumoxytol
(24 hours)
Ferumoxytol
Ferumoxytol USPIO is a blood pool agent in
the early phase
• Appropriate for Dynamic MRI
• Perfusion measurement is not confounded by
BBB permeability
• Suggesting more accurate rCBV values
Ferumoxytol: an alternative imaging
agent for patients at risk for NSF
– 1,700 ferumoxytol patients to date (too small to
accurately evaluate risk of NSF or other
complications)
– Ferumoxytol previously tested in patients with
renal failure
• Over 1700 patients exposed, 1500 with CKD in Phase
III iron replacement studies- only 1 patient has
experienced anaphylactoid reaction
CNS
imaging
in kidney
disease
patients:
Enhance
d safety
Ferumoxytol MRI clinical trials
Protocol 1. 3 Tesla versus 7 Tesla MRI
Dynamic imaging at 3 vs 7 Tesla
Ferumoxytol versus gadolinium contrast
Protocol 2. Early assessment of tumor response to
therapy
Dynamic MRI during the course of radiochemotherapy
12 GBM patients
Protocol 3. Ferumoxytol in CNS inflammation
Ferumoxytol versus gadolinium contrast
Utility of ferumoxytol to differentiate inflammatory and
neoplastic lesions
Subjects include MS, stroke, cardiac surgery
Ferumoxytol imaging at 7T in human brain
Prior to ferumoxtyol
After ferumoxytol
What is a perfusion MRI?
What contrast agent should we use
during perfusion MRI?
Signal Intensity
MR perfusion:
Repeated scans of the same regions
after iv. contrast bolus injection
Blood
Volume
Assumes no
extravasation
Mean
Transit Time
Time
Comparison of gadodiamide and
ferumoxytol perfusion
Shown is an example using highly vascular and permeable human glioma
(U87) rat model in a 12 Tesla MRI. Gadolinium chelates underestimate CBV,
perfusion measurement assumes no extravasation.
Time of Flight (TOF)
Angiography
Without contrast
15 min. after GBCA
15 min. post
ferumoxytol
Perfusion MR, time-intensity curves
Signal Intensity
Signal Intensity
Time
gadolinium - leak
Time
24 h later
ferumoxytol - no leak
Hypothesis:
Ferumoxytol will show a good safety
profile, as well as enhanced imaging, in
patients where improved imaging of
CNS lesions may improve patient
management
Preliminary results using
DSC-MRI with Ferumoxytol
for the purpose of differentiating
pseudoprogression from true tumor
progression
“Pseudoprogression”
Subacute treatment-related reactions in
human gliomas, showing edema and
sometimes new or increasing contrast
enhancement on magnetic resonance
imaging (MRI)
Brandsma, stalpers, Taal et al : Lancet Oncol 2008; 9:453-61
Dynamic Imaging and high Grade glioma
Cerebral blood volume is an important prognostic factor
Low rCBV
High rCBV
Materials and Methods
• 18 patients with biopsy proven WHO Grade IV
glial tumors were prospectively studied in 3
different IRB-approved protocols evaluating
dynamic imaging using Ferumoxytol on 3T MRI
• In 14 patients, after radiochemotherapy, Gd
enhanced MRI and DSC-imaging using Gd and
Ferumoxytol were obtained
MRI Imaging methods
Day 1: Gadolinium injection
Anatomical MRI, DSC, DCE, DWI, and MRA
Day 2: Ferumoxytol injection
Anatomical MRI, DSC, DCE, DWI, and MRA
Day 3: No injection
Anatomical MRI
Treatment of patients with
pseudoprogression
• Asymptomatic
patient
continue temozolomide
• Symptomatic patient: temozolomide +
•Steroid
•Bevacizumab (Avastin)
•Surgery
Pseudoprogression followed by true tumor progression
after radiochemotherapy (RCT)
2 mo after RCT
Before RCT
25 mo after RCT 28 mo after RCT
No
contrast
A
C
G
J
B
D
H
K
GBCA
E
F
Gd-rCBV
L
Fe-rCBV
M
Gd-rCBV
Fe-rCBV
Mixed response 1 month after radiochemotherapy (RCT)
followed by 2 courses of Bevacizumab
Before surgery
Before RCT
1mo after RCT
After 1 Tx
After 2 Tx
Gadoteridol
A
C
B
Gd-rCBV
Fe-rCBV
F
G
Regression after radiochemotherapy (RCT)
No contrast
Gadoteridol
Gd-rCBV
Fe-rCBV
Before RT
A
B
C
D
E
F
G
H
J
K
After RT
14 months
after RT
Comparison of rCBV acquired by DSC-MRI using Ferumoxytol vs
Gadoteridol:
Tumor vs Pseudoprogression vs Mixed response
*
*
*
**
*
* P < 0.00001 by ANOVA test
**
*
*
* P = 0.01 by ANOVA test
** Rapidly growing tumors are associated with rCBV > 1.7 in the literature
Comparison of rCBV acquired by DSC-MRI using
Ferumoxytol vs Gadoteridol
GBM cases: Ferumoxytol-rCBV vs Gadoteridol-rCBV
16
14
12
rCBV
10
Fe-rCBV
8
Gd-rCBV
6
p = 0.002
4
*
2
0
1
2
3
4
5
6
7
Patients
* Rapidly growing tumors are associated with rCBV > 1.7 in the literature
Conclusion
• rCBV measurement is possibly more accurate with
ferumoxytol than using Gadolinium contrast agents
• Increasing gadolinium enhancement on MRI with
decreasing rCBV on DSC-MRI using Ferumoxytol may
represent pseudoprogression
• Improvement can be achieved in symptomatic patients
with pseudoprogression by using bevacizumab
Avastin versus Steroid
Varallyay C, Muldoon LL, Gharamanov S, et al.
Dynamic MRI using a blood pool agent ferumoxytol
and gadodiamide in evaluating early vascular effects of
dexamethasone and bevacizumab in an intracerebral
glioma model. J Cereb Blood Flow Metab,
In press, 2009.
rCBV: Avastin vs. Steroids
Permeability:
Avastin vs. Steroids
Permeability:
Avastin vs. Steroids
Avastin at 24 h dramatically decreases CNS tumor
delivery of Methotrexate
0.1
0.09
0.08
DPM/gm
0.07
0.06
0.05
0.04
MTX alone mean
MTX+bev mean
0.03
0.02
0.01
0
Tumor
Brain
Brain Distal
Left
Adjacent to to Tumor Hemisphere
Tumor
Location of Sample
Avastin:
Is less chemotherapy delivery better?
Jahnke K, Muldoon LL, Varallyay CG, et al.
Bevacizumab and carboplatin increase survival and asymptomatic
tumor volume in a glioma model.
Neuro Oncol 2008 Sep 4. [Epub ahead of print]
Efficacy of Avastin and
Chemotherapy
Group
Survival
(days)
Control
16
Bevacizumab
23
Carboplatin
22
BEV + Carbo
36
Avastin synergistically increased the efficacy of
chemotherapy in a rat glioma model
Increased survival with asymptomatic
tumor growth in a rodent model
Progression-free survival in
patients
Questions:
• Does Avastin decrease chemo delivery?
• Why do patients live longer after Avastin?
• Is carbo better than ironotecan?
Conclusion
Is more better?
Depends
Future directions in targeting the
tumor vasculature
Imaging, efficacy, and
prophylaxis with anti- VEGF and
anti-integrin mAb in intracerebral
tumors: Preclinical Studies.
Project Aims
Aim 1. To determine the effects of antibodies
targeting existing tumor vasculature in nude
rat brain tumor models.
Aim 2. To evaluate the efficacy of targeting
antibodies for brain tumor therapy.
Aim 3. To assess the potential for antibodies
targeted to the CNS vasculature to block the
development of CNS metastases.
CNS tumor cell localization in the
hematogenous metastasis model
Vascular localization of Q-dot
labeled 231BR-HER2 human
breast cancer cells 3 days after
intra-carotid infusion.
Infiltration of Q-dot labeled
231BR-HER2 breast cancer cells
into cerebellum 7 days after intracarotid infusion.
MRI of breast cancer brain
metastasis model
231BR-HER2 human breast cancer cells were
labeled with Feridex SPIO and injected into the
carotid artery, in a female nude rat with cytoxan
pretreatment.
Tumor formation in the breast cancer
brain metastasis model
MRI (T1 + gadolinium, 3T) and histology (cytokeratin)
show multiple breast cancer metastases in rat brain 6
weeks after intracarotid tumor cell infusion.
Hypotheses
Antibodies targeting CNS vasculature will have antiangiogenic and/or angiolytic activity in established
brain tumor vasculature.
Antibodies targeting integrin and/or VEGF will block
metastatic cell adhesion, brain infiltration, and/or
angiogenesis in a hematogenous model of breast
cancer brain metastasis.
BBB Program
Acknowledgements
Hatton Institute
Robert Albright
Nancee Albright
Hadassah Medical Center
Tali Siegal
Edna Shalom
Ohio State University
John McGregor
Sue Bell
Cleveland Clinic Foundation
Gene Barnett
David Peereboom
Lily Angelov
Glen Stevens
University of Minnesota
Matthew Hunt
Stephen Haines
Katie Halbert
Patti Bruns
University of Oklahoma
Mary Kay Gumerlock
Carol Young
Disclosure
Drs. Neuwelt and Muldoon, Oregon Health & Science University (OHSU),
Portland Veterans Affairs Medical Center (PVAMC) and the Department of
Veterans Affairs have a significant financial interest in Adherex, a company that
may have a commercial interest in the results of this research and technology.
This potential conflict of interest was reviewed and managed by the OHSU
Integrity Program Oversight Council and the PVAMC Conflict of Interest in
Research Committee.
Dr. Neuwelt has divested his financial interests in Adherex.
The studies were entirely funded by Veterans Administration and NIH research
grants, with the ferumoxytol USPIO nanoparticles donated by AMAG
pharmaceuticals. In light of the results from this study, and subsequent to
completion of the manuscript, OHSU has received a sponsored research
agreement from AMAG to conduct clinical trials of MRI with ferumoxytol. None
of the authors has financial interest in this agent or in its developer AMAG.
The following grants helped fund this
research:
• NIH:
– NINDS Grants NS33618, NS34608,
NS44687, NS53468
• Veteran’s Administration Merit Review