Neurotrophins Promises

Neuroprotection, Neuro-restoration

NGF, BDNF, Nerturin

Limitations

Poor bio-availability in target organ following systemic peripheral delivery

Undesirable side effects from non-targeted central delivery, e.g. generalized sprouting promoting

inappropriate connections, neuralgia

Solutions

Localized (chronic) central delivery to affected region(s)

Surgical implants for localized infusion (GDNF)

Targeted delivery

Gene therapy (Tuczyinski 2004) via implantation of genetically modified fibroblasts;

CERE-110 – viral delivery of NGF (recruiting P2, n=50 end May 2012)

CERE-120 (AAV2-Neurturin) - P2 (Dec 2008): Failed on 1o endpoint (efficacy in motor function at 12

mo), may have benefit at 18 mo. OLE in progress

Immunotherapy targeting Ab for AD

Formerly the exclusive domain of small molecule

Potential of biologics for Rx of Neurodegenerative disease

Phagocytosis of plaque triggered by antibody opsonization of amyloid

Ab peptide active immunization

Anti-Ab mAb passive

immunization

Initial Results of Immunotherapy: Active &

Passive Immunotherapy targeting Ab

Preclinical Observations

Induces clearance of plaques, improvement in synaptic density, reduces gliosis

Efficacy in behavioral testing

Multiple potential mechanisms: antibody induced plaque phagocytosis, peripheral sink

Clinical observations with AN1792

Plaque clearance and reduced plaque associated neuropathology

Significant effect on NTB

P2 trial halted due to meningioencephalitis in subset of patients

Attributable to T-cell epitopes in full length Ab peptide

Epitope mapping of responders combined with pre-clinical studies suggests safer follow-on approaches

M. Lee et al, Ann Neurol 2005

• No reaction to APP

• Binds to plaques

• Adsorbable by linear peptide

Antibody Response in AN1792 treated AD Patients is

Specific to the Amino Terminus of Ab

Preclinical Endpoints Effected By Immunotherapy with

3D6, the Murine Precursor of Bapineuzumab

Neuriticdystrophy

Astrogliosis

Neutralization of neurotoxic Ab species

Vascular Amyloid

3D6: Very similar to AN1792-induced antibodies Binds amino-terminus of Ab, but not APP

Recognizes both plaques and soluble forms of Ab

Chronic efficacy testing in PDAPP mouse model of AD Treatment and prevention models, following

chronic therapy

Positive on broad spectrum of efficacy end-points

Principles of Drug Development Exemplified in

Ab Targeted Immunotherapy

Access to target organ

CNS:Plasma exposure of drug

Target engagement

Biological readout of drug activity

Translational medicine

Preclinical clinical observation

Bard et al., 2010“Unique Brain PK Properties of 3D6 and Bapineuzumab Depend on Cerebral Amyloid Load in PDAPP Transgenic Mice” P4-406, ICAD 2010

2 7 14 21 27 2 7 14 21 27 2 7 14 21 270

2500

5000

7500

10000

Cerebellum CortexHippocampus

Day post-injection

cpm

/gm

tis

sue

2 7 14 21 271000

10000

100000

1000000

Day post-injection

cpm

/ gm

tis

sue Serum

Hippocampus

140x65x

15x

6x4x• Peak accumulation of binding occurred ~14 d post injection and remains stable up to 27

days• Accumulation continues even as antibody serum levels drop over two weeks

The 125I-3D6 t1/2 is longer in the brain than in the serum

Access of drug to target organ

Target Engagement

Elevation of plasma Ab via prolongation of t1/2 Seubert et al (2007), Neurodegenerative Dis. 5:65-71;

Gray et al. (2007) Neuroreport 18: 293

Mobilization of deposited central Ab Pre-clinical: dose dependent increased vascular

Ab, microhemorrhage Wilcock 2004) J Neuroinflammation 1:24

Racke (2005)J Neurosci 25:629

Schroeter (2008) J Neurosci 28:6787

Clinical: Vasogenic edema/ ARIA Sperling (2012) The Lancet: DOI 10.1016/S1474-4422(12)70015-7

Clinical translation of pre-clinical

Observations

Reductio

n of Ab

amyloid

pathology

in brain

1. Ab Immunized PDAPP Mice Schenk, D. (1999) Nature 400:173

2. AN 1792 (A-beta) Immunized patients Nicoll, J et al. (2006) J. Exp. Neurol. &

Exp. Neur. 65:1040

3. BapineuzumabTreated patient

Rinne, JO (2010) Lancet Neurol. 9:363

A proliferation of biologics in preclinical

discovery for neurodegenerative disease

Immunotherap

y

AD (Ab

Tau, BACE);

PD (a-Syn);

Targeted

Delivery via

Engineered

Biologics

Immunotherapy Engineered Biologics (mAbs, Fc-Fusions, etc.)

Tau Immunotherapy

Efficacy on tau pathology and behavior end-points following active and passive Rx targeting PHF tau epitope in FTD mouse model

Sub-cellular localization of internalized Antibody in brain slice model

“Prionoid” agents in

Neurodegenerative Disease

Transmissab

le

pathogenic

element, e.g.

tau, supports

rationale for

immuno-

therapy with

antibody

antagonist

Antagonist antibody targeting BACE, a

traditional small molecule target

Case by case opportunities employing Targeted

Delivery

Anti-BACE immunotherapy

Anti-BACE mAb IC50 ~ 3 nM

Central reduction of Ab following peripheral administration in mice (brain) and primate (CSF) at 30 or 100 mg/Kg

Atwal JK, Chen Y, Chiu C, Mortensen DL, Meilandt WJ, Liu Y, Heise CE, Hoyte K, Luk W, Lu Y et al. 2011. A

therapeutic antibody targeting BACE1 inhibits amyloid-beta production in vivo. Science translational medicine 3:

84ra43.

Brain:Plasma of non-targeted anti-

BACE

Atwal JK, Chen Y, Chiu C, Mortensen DL, Meilandt WJ, Liu Y, Heise CE, Hoyte K, Luk W, Lu Y et al. 2011. A therapeutic

antibody targeting BACE1 inhibits amyloid-beta production in vivo. Science translational medicine 3: 84ra43.

Leveraging Transferrin Receptor

for Brain Delivery of Cargo

TfR expressed on

brain endothelial

cells

Bi-specific anti-

TfR/BACE mAb

Improved brain

accumulation cf

parent anti-BACE

2X improvement in

efficacy (25mg/Kg

vs 50 mg/Kg) for

lowering brain Ab

Yu et al., (2011) Science Translational Med. 3: 84ra44

Pharmacokinetics considerations of

targeted delivery of antibodies

CNS and peripheral expression of carrier mediated transport targets e.g. TfRand InsRcontributes to rapid clearance of mAb from circulation, with t1/2 ~ small molecules

Boado, R.J., Hui, E. K. W., Lu,J. Z., and Pardridge, W. M. (2009b). AGT-

181: Expressionin CHO cells and pharmacokinetics, safety, and plasma

iduronidase enzyme activity in Rhesus monkeys.). Biotechnol. 144, 135-141.

• Order of magnitude drop

in plasma concentration

of drug by 2h following IV

administration attributable

to uptake via peripheral

insulin receptor

• mAb Volume of

distribution ~ plasma

volume

• Transport receptor

targeted mAb volume of

distribution ~ small

molecule

Challenges Associated with Targeted

Delivery for CNS indications

Bi-specific targeting modalities, e.g. BACE

Scalable manufacture of bi-specific mAb

Cost of Goods:

Hu eq dose BACE/TfR = 1.75g/70kg;

Tysabri: 300 mg IV, q4 wks

Humira: 40-160 mg IV, qw – q4 wk

Dosing interval BACE/TfR?

Monthly = 21g/person/yr

Bimonthly = 42g/person/yr

300 person 1 yr P2 trial = 12.6 kg drug product

Advantages of Traditional mAbs

Long t1/2

IV-transfusion, infrequent dosing (monthly)

PK Advantages Negated by transport receptor targeted delivery

More Frequent dosing depending upon:

Target:Ligand stoichiometry demands for desired pharmacologic outcome

Pharmacodynamic effect if target engagement may allow less frequent dosing

CMC, timeline to IND, and cost

considerations

Antibody Technologies

Growth of Antibody Therapeutics

Nelson AL, Dhimolea E, Reichert JM. 2010. Development trends for human monoclonal antibody therapeutics.

Nature reviews Drug discovery 9: 767-774.