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TREATMENT OF BRAIN TUMORS

Simon R Platt BVM&S MRCVS Dipl. ACVIM (Neurology) Dipl. ECVN

Professor, Dept. Small Animal Medicine & Surgery College of Veterinary Medicine, University of Georgia

Current Problems in Veterinary Neuro-Oncology Literature

•  Case numbers •  Owner Finances •  Pets >> animals •  Stage of disease is often late at presentation •  CT guided biopsy •  Radiation therapy •  Surgical Techniques •  Treatment trials flawed by inclusion criteria and measures of

outcome

Classification & Grading Systems

Histologic Classification of Tumors of the Nervous System of Domestic Animals. A Koestner et al; 1999, Armed Forces Inst. Of Pathology, WHO, Washington DC.

Classification based on characteristics of constituent cell type & pathologic behavior

Canine Brain Tumors: Classification

1.  Neuroepithelial ¡  Astrocytic ¡  Oligodendroglial ¡  Mixed Gliomas ¡  Ependymal ¡  Choroid-plexus ¡  Neuronal ¡  Embryonal ¡  Unclassified

2.  Meningeal •  Meningioma •  Histiocytic sarcoma •  Granular cell tumor

3.  Primary CNS Lymphoma

4.  Germ-cell

5.  Metastatic

Classification & Grading Systems

• WHO Grading = 1 component of criteria to predict response to therapy and outcome

I – Low proliferation potential – surgical cure II – Infiltrative / low proliferation – may recur or progress III – Histological evidence of malignancy – adjuvant therapy required IV – Cytologically malignant / necrosis / mitoses

WHO Grade I II III IV

Astrocyte Pilocytic astrocytoma

(Diffuse) astrocytoma

Anaplastic astrocytoma

GBM

Oligodendroglia Oligodendroglioma

Anaplastic oligo GBM

Mixed Glial

Oligoastrocytoma Anaplastic oligoastrocytoma

GBM

Ependymal Sub-ependymoma

Ependymoma Anaplastic ependymoma

Choroid Plexus CP Papilloma Atypical CPP CP Carcinoma

Meningeal Meningioma Atypical meningioma

Malignant meningioma

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Canine Brain Tumors

•  Canine brain tumors have a similar incidence (14.5/100,000?;2-4.5%) to humans (20.5;2-3%)

•  The types and classes of canine brain tumors seen are similar to those seen in humans

•  The diagnostic and therapeutic options are also similar but outcome more variable

•  Variables shown to influence the outcome include age, neuro status, extent of surgery possible, lesion location, histo type, molecular expression

•  Most tumors (1) affect telencephalon [60%] (2) solitary (3) primary (4) affect dogs >7yr (95%: mean age 9.4 yr)

Meningioma

•  Most common brain tumor (45-50%) in dogs / median age 10-11 yr / G Ret & Boxer /no sex predilection?

•  From arachnoid tissue (caps cells) in multiple

locations - mesenchymal and epithelial composition

•  Invariably lack demarcation from normal brain (27%) in dogs and demonstrate necrosis & cystic in 25-30% of dogs

•  Falx/convexity/parasellar/cerebellar /brainstem

•  Benign (56%) vs. Atypical (43%) vs. Anaplastic (1%) •  {Sturges et al; 2008 JVIM;596}

Meningioma •  > 90% Vimentin and S100 positive

•  Most positive for Neuron specific enolase

•  Infrequent GFAP & cytokeratin positive

•  70-100% have progesterone receptors

•  All express VEGF, PCNA & Ki-67

•  >90% express VEGFR-1&2 & EGFR-1

•  Expression relates to grade and prognosis Theon et al; 2000; JAVMA;p701 Adamo et al:2003; AJVR; p1310 Montoliu et al: 2006; J Comp Path; p200 Platt et al: 2006; JVIM; p663 Dickinson et al 2006; Vet Comp Onc;p132 Mandara et al: 2002; J Comp Path; p214 Rossmeisl et al; 2007; AJVR; p1239

Meningioma - Comparative Genomic Hybridization

possible tumor DNA

amplification

possible tumor DNA

deletion

Astrocytomas •  2nd most common brain tumor (17% ) in dogs / mean age 8.6 yr / Border Terrier, Boston terrier, Bulldog & Boxer (21%) /no sex predilection

• Most in cerebrum & diencephalon (8x more likely) / 28% in cerebellum

• Variants of astrocytoma reported include fibrillary, protoplasmic, pilocytic, anaplastic and gemistocytic

•  Intratumoral hemorrhage is uncommon

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Progression of Glial Tumors

Criteria Diffuse Astrocytoma

Anaplastic astrocytoma

Glioblastoma multiforme

Hyper-cellularity

Slight Moderate Moderate

Pleomorphism Slight Moderate Moderate

Mitosis None Present Present

Vascular proliferation

None Present Present

Necrosis None None Present

Astrocytomas • 35% of canine astrocytomas exhibit positive immunolabeling for p53 alteration

• 23% of canine astrocytomas exhibit positive EGFR labeling

• 84% GFAP positive (especially in differentiated areas) – chemical subunit of intracytoplasmic intermediate filaments

Stoica et al; Vet Pathol; 2004;p10 Snyder et al; JVIM: 2006; p 669

Oligodendrogliomas

•  Median age 8.1yr •  14% of all primary CNS tumors / 28% of gliomas •  >50% border ventricle •  Capillaries tend to proliferate •  Do not stain vs. all stain with GFAP?? •  Ki67 correlates with degree of malignancy

•  Vandevelde et al; 1985: Acta Neuropathol p111 •  Higgins MA et al; 2007 ACVIM abstracts

Glioblastome Multiforme

• Mean age 8.4 yr • 3% of all primary CNS tumors / 12% of all neuroglial

tumors • Can be de novo or result from progression •  Infiltrative and destructive / well vascularized and

necrotic • 5/5 GFAP positive • 6-26% Ki67 expression • 40% VEGF expression / 60% EGFR expression Lipsitz et al: 2003; Vet Path:p659

Secondary Neoplasia

•  50% of all intracranial tumors • Mean age 9.6yr • Most in telencephalon •  29% HSA •  25% pituitary tumors •  12% LSA •  12% metastatic carcinomas

Snyder et al; 2008: JVIM; p172

Canine Brain Tumors: Treatment Options

•  Conservative / Palliative •  Definitive Therapy 1.  Surgical Debulking 2.  Chemotherapy 3.  Radiotherapy 4.  Radiosurgery 5.  Gene Therapy 6.  Immunotherapy

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Treatment Options Palliative Care

Corticosteroids -Mean Survival Canine Meningiomas

Ø  75 days (n=13; range 1-405d) Foster ES, et al: JVIM 1988

Canine Astrocytomas Ø  77 days (n=7; range 7-150d)

Foster ES, et al: JVIM 1988

Canine 1’ Brain Tumors Ø  6 days (n=45) Heidner GL, et al: JVIM

1991 Ø  81 days (n=8) Turrel JM, et al: JAVMA

1981 Ø  59 days (n=8) Turrel JM, et al: JAVMA,

1984

Treatment Options Intracranial Surgery

Role of surgery 1.  Reduce mass effect 2.  Establish a diagnosis 3.  Cytoreduction 4.  Deliver local treatment

Contraindications 1.  Deep locations 2.  Poor status 3.  Metastasis? 4.  Multiple lesions?

Treatment Options Intracranial Surgery

Surgery Alone - Mean Survival Canine Meningiomas Ø 210 days (n=14) Axlund TW, et al: JAVMA 2002

Ø 138 days (n=4; 63-203d) Kostolich M, et al: Vet Surg 1987

Ø 198 days (n=10) Niebauer GW, et al: JAVMA 1991 Ø 1254 days (n=17) Greco JJ et al: JAVMA 2006

Ø Higher median survival if transitional / meningothelial Ø 2104 days (n=39) Klopp & Rao, JVIM 2009

Treatment Options Radiation Therapy

• Deliver tumoricidal dose of radiation while sparing normal brain tissue

• Improvements in treatment planning have resulted in improved local control and a decrease in CNS side-effects • External beam megavoltage most commonly used • Superfractionation / Sensitisation / BNCT / Hyperthermia / Brachytherapy / Radiosurgery

Treatment Options Radiation Therapy

Side-effects in dogs 1.  Superficial tissues Ø KCS, otitis, dermatitis, mucositis,

corneal ulcer 1.  CNS

Ø Acute – wks to months 10% dogs?

Ø Early Delayed Ø Late Delayed – only 5-20% still

alive Ø risk related to total dose (<48Gy) /

fraction size (<3Gy) / number of fractions / extent of disease / neuro status

Treatment Options Radiation Therapy

Radiation Alone - Mean Survival Canine Primary Brain Tumors Ø 225 days (n=16) Turrel JM, et al:Proc VCS 1986 Ø 345 days (n=14) Evans SM, et al: JVIM 1993 (0rthoV) Ø 322 days (n=4) Turrel JM, et al: JAVMA 1984 Ø 140 days (n= 25) Heidner GL, et al: JVIM 1991 Ø 250 days (n=29) Spugnini EP, et al: Vet Radiol & US 2000 Ø 344 days (n=15) LeCouteur R, et al: Int J Rad Oncol Biol Phys

1988

Canine Extra-axial Masses Ø 370 days (n=35) Brearley, et al:JVIM 1999

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Treatment Options Radiation Therapy

• Stereotactic radiotherapy •  1+ fractions •  MST 399 days for meningioma

Mariani et al. Vet Comp Oncol. 2013 www.csuanimalcancercenter.org

Sx alone

Sx & Rad

Treatment Options Surgery & Radiation

Canine Meningiomas Ø 610 days (n=12) Axlund TW, et al: JAVMA 2002

Ø 1150 days (n=20) Theon A, et al: JAVMA 2000

Ø 441 days (n=6) Brearley MJ, et al: JVIM 1999

Prognosis Associated with: Ø PCNA expression

Ø VEGF expression

Ø Progesterone expression

Treatment Options Chemotherapy

•  Nitrosurea Alkylating Agents – Carmustine (BCNU) & Lomustine (CCNU) Meta-analysis of 17 human trials showed increase in survival when used in addition to

RT but only in a sub-population: Young / Good Neuro status / Min Residual disease after surgery

Canine Clinical Trials – 5 astrocytomas CCNU mean survival 218 days Fulton et al, 1990 3 Meningiomas post surgery – median survival 552 days Bilderback et al ACVIM 2006 / 71 dogs with intracranial masses CCNU No survival benefit vs. symptomatic Meervenne et al. J Vet Comp Oncol. 2014

•  Platinum-based agents – Carboplatin / Cisplatin

•  Temozolamide (Temodar)– Recurrent astrocytomas and in combo with RT for GBM

• Bevacizumab (Avastin)- Anti-VEGF Ab; Recent data suggests limited survival benefit •  Procarbazine – Not cross-resistant with Nitrosureas / combined with CCNU and vincristine •  Hydroxyurea – 50mg/kg tid PO without side-effects in dogs

•  Ribonucleotide reductase inhibitor

Delivery of Local Chemotherapy • Desire to avoid BBB, drug efflux mechanisms and high plasma protein binding

• Carmustine (Gliadel) wafers •  Human glioma/GBM •  Resection cavity •  Gliadel wafer vs. placebo

•  MST 13.9mos vs 11.6mos •  CSF leak and intracranial

hypertension in Gliadel group •  Anecdotal reports in dogs

• Early work on CED, microspheres and nanoparticles to deliver drugs

www.gliadel.com

Westphal et al. Neuro-Oncol. 2003

(i) Convection-Enhanced Delivery (CED)

•  Approach developed to overcome BBB •  High drug concentrations without toxicity to normal tissue •  Distributes a product directly to the brain

•  Safe, reliable, targeted, homogeneous method •  Relies on bulk flow

•  Driven by small hydrostatic pressure differential to distribute molecules within the interstitial spaces of the CNS

•  Pressure gradient between infusion site and surrounding tissue

•  Long retention and slow dispersion of agents •  Agent visualization remains a challenge

•  Radio-labeled agent •  Co-infusion of MRI contrast agent •  Liposomes containing MRI contrast agent

(i) Convection-Enhanced Delivery (CED)

•  Several factors influence tissue CED drug distribution •  Drug flow rate •  Drug volume •  Drug viscosity •  Size, shape and placement of cannula

•  Drug back-flow is major issue and related to catheter size, catheter position in brain and infusion rate

•  Reflux prevents continued pressure in the EC space that drives bulk flow away from the catheter

•  Systemic toxicity likely due to reflux into CSF

•  Real-time imaging ensures treatment volumes are consistent

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CED in Dogs

• Convection-enhanced delivery •  CPT-11 (Irinotectan)

•  Topoisomerase 1 inhibitor •  Liposome carrier •  Reduced tumor volumes in canines

•  Correlated to Vd of tumor

•  Cetuximab •  EGFRvIII antibody •  Conjugated to iron oxide in nanoparticles

Dickinson et al. Neuro-Oncol. 2010 Platt et al. Clin Neurosurg. 2012

Cetuximab (C225; Erbitux) § Monoclonal IgG1 antibody § Chimeric (65% human & 35% mouse)

§ Binds EGFR extracellularly ú  Competitive inhibition ú  Inhibits downstream signals ú  Cell cycle arrest in G1 phase

§ NO relation between EGFR expression and response to cetuximab

§ Effects ú  Enhances radiosensitivity ú  Promotes RT induced apoptosis ú  Decreases cell invasion & proliferation ú  Reduces angiogenesis ú  Inhibits radiation induced damage repair & angiogenesis

Iron Oxide Nanoparticles (IONPS)

§ 10-25 nm § Provide simultaneous imaging and therapeutic efficacy ú Tumor targeting ú Therapy with conjugated drug delivery, and/or hyperthermia

§ Biocompatible § Low toxicity § Evade immune system § Taken up by tumor cells § Decrease cell survival of human GBM cells in vitro

§ Increased survival of mice with CED of IONPs alone

Magnetic IONPs

Iron Oxide Nanoparticles (IONPS) THERMOTHERAPY

•  IONPSheatduetoalternatingmagneticfield•  Thermoablationofcancertissue•  SCCHNinnudemice•  SQflankinjection•  Tumorcenterincreasedto40°Cwithin5mins•  Maintainedfor20mins

Magnetic IONPs

Catheter

Cetuximab-IONPs

100x

A.

C.

B.

IR 0.5 µl/min

Day 0 24 hr

Day 30

IR 0.5 µl/min B.

D.

MRI-guided Cetuximab-IONP CED in the canine brain

IR 0.5 µl/min 24 hour

Coronal Preop w/Gad Axial Preop w/Gad Axial Preop T2 GE

Axial Postop T2 GE

Tumor

Cetuximab-IONPs

Residual Tumor Residual Tumor

Cetuximab-IONPs

Axial Postop w/Gad

7 d Postop 24 h Postop

24 h Postop

Tumor Tumor

Coronal Postop T2

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(ii) Microsphere Delivered Therapy

• Poly(lactide-co-glycolide) microspheres •  PLGA •  Slow degradation

•  Potential for extended-release therapy

www.controlledreleasesociety.org

PLGA Microspheres • Microparticle drug delivery

•  Drugs elute via diffusion or degradation

• PLGA microspheres •  Degradation via hydrolysis •  Metabolized to CO2 and H2O •  Degradation rate varies •  γ-irridiation sterilization

Menei et al. Expert Opin Drug Deliv. 2005

PLGA Microspheres- Uses

•  Initial studies •  BCNU (carmustine) and carboplatin microspheres

•  Increased survival rat glioma model •  Injection into walls of resected tumor cavity

•  For non-resectable, injection at edges of tumor may be superior

•  5-fluorouracil microspheres •  Lack of toxicity/improved survival in murine model •  >3 weeks drug delivery

Menei et al. Expert Opin Drug Deliv. 2005

UGA Cadaver Study- MRI

Day 1 vs. Day 5

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UGA Cadaver Study- MRI UGA Safety study- MRI

Day 1 Day 28

UGA Safety study- Histopathology

12 microcylinders, 6.25% Gad

6 microcylinders, blank

6 microcylinders, 6.25% Gad

(iii) Nanoparticle Delivered Drug Therapy

• Platin-M: modified platinum(IV)-prodrug of cisplatin •  Crosses blood-brain barrier •  Delivered via biocompatible polymeric nanoparticles (NPs) •  Targeted to the mitochondrial matrix of hyperpolarized cancerous

cells

OO

OO

OOO

PPh3

PLGA-b-PEG-TPP

nyx

Br-

PtH3N ClClH3N

OO

O

N

O

HN

OPh3P

ONNN

N

O NH

OPPh3

Br-

NN N

Platin-MBr-

Nanoprecipitation +

Size: 51.3±0.8 nm Zeta Potential: 44.0±1.2 mV

Marrache, et al. 2014

MTT Cytotoxicity Assay

•  J3TBG Glioma Cells

•  SDT3G Glioblastoma Cells

-1 0 1 20

50

100

Log Concentration (µM)

%V

iabili

ty Cisplatin

Platin-M

NT-Platin-M-NP

T-Platin-M-NPs

IC50: >50 µM

IC50: 0.87 µM

IC50: 22 µM

IC50: 12 µM

0 1 20

50

100

150

Log Concentration (µM)

%V

iabili

ty Cisplatin

Platin-M

T-Platin-M-NPs

IC50: 26 µM

IC50: 5.7 µM

IC50: 0.5 µM

MitoStress Assay by Seahorse Assay

• J3TBG Glioma

• SDT3G Glioblastoma

0 20 40 60 80 100-20

02040

100

200

300

400

500

Time (min)

OC

R (p

Mol

es/m

in)

Control Cisplatin Platin-M T-Platin-M-NPs

FCCPOligomycin Antimycin A + Rotenone

0 20 40 60 80 100-20

02040

100200300400500600700

Time (min)

OC

R (p

Mol

es/m

in)

Control Cisplatin Platin-M T-Platin-M-NPs

FCCPOligomycin Antimycin A + Rotenone

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Canine Biodistribution

0

50

100

150

200

250

300

Brain Heart Lung Liver Kidney Spleen

Par

ts P

er B

illio

n, P

latin

um T-Platin-M-NP Biodistribution

Dog 1

Dog 2

Other Treatment Options

Nonthermal irreversible electroporation (N-TIRE) •  Electrodes deliver short intense electrical pulses •  Increase membrane permeability •  Blood vessels intact Immunotherapy •  Mobilise T-cell mediated immunity against a brain tumor •  E.g.,Culture and stimulate autologous lymphocytes Hormonal Therapy •  Anti-progesterone therapy in meningiomas Molecular Targeting •  EGFR / VEGFR / PDGFR •  Toceranib & masitinib Toxin Conjugates •  Tumor cell receptor ligand bound to toxin •  Pseudomonas-derived IL-13 toxin conjugates Gene Therapy •  DNA or RNA transferred to target cells for therapeutic purposes •  Antioncogenes to glioma cells •  Delivered via viral vectors •  None have shown efficacy in high grade gliomas at phase III

trials

Feline Intracranial Neoplasia •  3.5/100,000 • No breed predisposition • Overall mean age = 11.3yrs •  33-59% meningioma •  16-31% lymphoma •  9% pituitary •  8-15% all glial •  5.6% metastases Troxel et al;2003: JVIM;p850

Feline Intracranial Neoplasia

• Upto 20% have multiple tumors – 50% same type

•  Incidental in upto 20% • Most common signs are altered

consciousness (26%) / circling (22%) / seizures (22-23%)

Tomek et al: 2006; J Fel Med & Surg;p243

Feline Intracranial Meningioma

• Median age 12.2 yr • Male >> female • MPS I cats predisposed •  87% supratentorial • Meningothelial and psammamatous •  49-73% hyperostosis MRI 96% specific Troxel et al; 2004; JVIM;p176

Feline Intracranial Neoplasia Surgery

•  Feline Meningiomas Ø 650 days (n=10; 60-900d)

Ø Lawson DC, et al: JAVMA 1984 Ø 485 days (n=4); 50% alive 2 yr later

Ø Niebauer GW, et al: JAVMA 1991 Ø 830 days (n=17; 540-1410d)

Ø Gallagher JG, et al: JAVMA 1993 Ø 685 days (n=34)

Ø Troxel et al: JVIM 2003 Ø 630 days (n=42; 40-1140d)

Ø Niebauer GW, et al: JAVMA 1991 •  10-25% peri-op mortality

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Questions??