Immunotherapeutic Strategies Immunotherapeutic Strategies for Alzheimer’s Diseasefor Alzheimer’s Disease

Cynthia A. Lemere, Ph.D.Center for Neurologic Diseases, Brigham &

Women's Hospital and Harvard Medical School, Boston, MA, USA

DisclosuresDisclosures

• Scientific Advisory Boards:

-- Neurophage Pharmaceuticals, Inc., Probiodrug AG, Cognition Therapeutics, Inc., Genentech, Inc.

• Consultant:

-- Baxter Healthcare, DIAN Consortium

Most common cause of dementia

Affects 5.4 mil Americans; > 30 mil worldwide

Occurs in all races and ethnic groups

No cure or effective treatment

(See www.alz.org for complete references)

Alzheimer’s Disease in 2012Alzheimer’s Disease in 2012

Alzheimer’s Disease: Hallmark LesionsAlzheimer’s Disease: Hallmark Lesions

Amyloid plaques Amyloid plaques (outside neurons): Composed of a 40-42 (outside neurons): Composed of a 40-42 amino acid peptide called amyloid -protein (A)amino acid peptide called amyloid -protein (A)

Neurofibrillary tanglesNeurofibrillary tangles (inside neurons): Composed of an (inside neurons): Composed of an altered form of a neuronal protein, taualtered form of a neuronal protein, tau

Aβ Immunotherapy for the Aβ Immunotherapy for the Prevention and/or Treatment of Prevention and/or Treatment of

Alzheimer’s DiseaseAlzheimer’s Disease

Aß proteinAß protein1 42

B cell epitope

T cell epitope

Aß1

Carrier protein

or

Active Immunization: Aß Protein Active Immunization: Aß Protein (injection, intranasal or transcutaneous)(injection, intranasal or transcutaneous)

T cellT cell

B cellB cellCellular

Release of Th1-mediated pro-inflammatory and/or Th2-mediated

anti-inflammatory cytokines depending upon antigen and adjuvant

Humoral

Imm

un

e R

esp

o nse

Passive Transfer: Aß Antibodies Passive Transfer: Aß Antibodies (i.v., s.c., or i.p. injection) (i.v., s.c., or i.p. injection)

or+ immune booster (adjuvant)

Aß-specific antibodiesAß-specific antibodies

Aß-specific antibodiesAß-specific antibodies

Aß antibodies bind Aß protein and target it for clearance

No

Imm

un

e R

esp

onse

?

Costimulatory molecules

2nd signal

Active vs. Passive ImmunizationActive vs. Passive Immunization

Pros Cons

Active: - long-lasting - immune risks- cost-effective - hard to “turn off”- large population - overlapping epitopes- fewer Dr’s visits

Passive: - does not require - monthly injections an immune response - expensive (hu mAb)- stopped easily - frequent Dr’s visits- specific targets - anti-antibodies (?)

Aβ Immunotherapy in RodentsAβ Immunotherapy in Rodents

Active Aβ immunization in AD-like Tg mice:

• Generates anti-Aβ titers

–Antibodies bind human AD plaques

–B cell epitopes within Aβ1-15

–T cell epitopes within Aβ16-42

Active and Passive Aβ Immunotherapies:

• Reduce cerebral Aβ burden

• Increase peripheral Aβ in blood; microhemorrhage?

• Improve behavior/cognition on certain tasks, especially if given early

Aβ Immunotherapy in J20 APP Tg MiceAβ Immunotherapy in J20 APP Tg Mice

J20 APP-tg mice (hAPPSw, Ind)/PDGF-promoter on a mixed C57BL/6 x DBA background (L. Mucke, UCSF)

Proposed MechanismsProposed Mechanisms

Fu et al. 2010 CNS and Neurological Disorders – Drug Targets

ELAN/Wyeth AN1792 Trial: Aβ1-42 + QS21ELAN/Wyeth AN1792 Trial: Aβ1-42 + QS21

• Phase 2a trial stopped Jan. 2002:meningoencephalitis in ~ 6% (18/300) ; anti-Aβ in 19% immunized patients

• Anti-Aβ antibodies recognize AD plaques and CAA but not soluble Aβ42 nor APP; recognize free N-terminus of Aβ

• Regionally reduced Aβ deposition in brain

• Reduced tau levels in CSF

• Transient cortical shrinkage by MRI in antibody responders

• Some slowing of cognitive decline, even 4.5 yr later (DAD)

• However, 2 patients who came to autopsy had few plaques and yet had severe dementia -- too little, too late????

Note: Living patients still show cognitive benefit.

AN1792 cleared plaques but did not slow AD AN1792 cleared plaques but did not slow AD

Holmes et al., Lancet 2008

• Possible causes for adverse events? T cell response to self-antigen, strong Th1 adjuvant, or possibly, a formulation change to include polysorbate 80 for vaccine stability

Next Steps….

• Passive immunotherapy: Monthly injections of anti-Aβ humanized monoclonal antibodies (mAb) targeting different binding sites and conformations of Aβ protein

• Second-generation active Aß vaccines: target B cell epitope in Aβ N-terminus and avoid T cell epitope; target Aβ oligomers; mimotopes; use Aβ-conjugates, DNA, phage, VLP, and AAV vaccines

ELAN/Wyeth AN1792 Clinical Trial:ELAN/Wyeth AN1792 Clinical Trial:

Passive Aβ IT in Mice: N-terminal Aβ mAbPassive Aβ IT in Mice: N-terminal Aβ mAb

• 3D6 Antibody gets into brain and induces Fc-receptor mediated phagocytosis of Aβ deposits

• Binds free N-terminus of Aβ; binds plaques

• Precursor to Bapineuzumab

Bard et al., Nature Med, 2000

Passive Aβ IT in Mice: N-terminal Aβ mAbPassive Aβ IT in Mice: N-terminal Aβ mAb

Science 2002

• mAb against Aβ3-6

• APP23 mice with CAA

• 21 mo-old mice treated for 5 mo

• Plaque lowering

• Significant increase in hemorrhage

PNAS 2001

• m266 increased plasma Aβ levels; reduced plaque burden

Dodart et al., Nature Neurosci, 2002:

• 6 wk chronic Tx reversed cognitive deficits in 2 yo PDAPP mice

• Single i.p. injection improved cognition within 24 hr

• Cerebral Aβ unchanged in both studies; plasma Aβ increased

• m266 is the precursor to Solanezumab

Passive Aβ IT in Mice: mid-region Aβ mAbPassive Aβ IT in Mice: mid-region Aβ mAb

J Neuroinflammation 2004

Passive Aβ IT in Mice: C-terminal Aβ mAbPassive Aβ IT in Mice: C-terminal Aβ mAb

• Bapineuzumab Phase III (Janssen/Pfizer)

• Solanezumab Phase III (Eli Lilly)

• MABT5102A Phase II (Genentech/AC Immune)

• Gantenerumab Phase II (Hoffmann-LaRoche)

• GSK933776 Phase II (GSK)

• Ponezumab Phase II (Pfizer/Rhinat) discontinued

• BAN2401 Phase I (Esai/BioArtic)

• Gammagard 10% IGIV Phase III (Baxter HC)

• Octagam 10% IVIG Phase II (OctaPharma) completed

• NewGam 10% IVIG Phase II (Sutter Health)

Passive Aβ Immunotherapy in HumansPassive Aβ Immunotherapy in Humans

Bapineuzumab: Aβ N-term IgG1 mAbBapineuzumab: Aβ N-term IgG1 mAbPhase II (2009; n=234): ELAN/Wyeth

• Signs of efficacy in “completers”, APOE ε4 non-carriers

• ε4 non-carriers had reduced brain volume loss

• ε4 carriers had ventricular enlargement

• Vasogenic edema in 12 ε4 carriers

• Reduced cortical 11C-PiB PET

retention compared to baseline

Phase III (ongoing): Janssen/Pfizer

• over 4,000 AD patients

• divided ε4 carrier/non-carriers

• Primary endpoints include efficacy and safety

• Trials will be completed 2012-2014

Rinne Lancet Neurol 2010

• Eli Lilly

• Recognizes full-length and N-term truncated soluble Aβ; prevents aggregation; increases plasma Aβ; cognitive efficacy in mice

Phase II:

• 52 AD pts, 16 healthy volunteers

• Safe; no signs of VE or microhemorrhage

• Increased plasma Aβ, incl. pyroglu3 Aβ; No cognitive efficacy

Phase III (ongoing):

• 2,000 AD pts Tx every 4 wk for 80 wk – completion Aug 2012

• 1,275 AD pts (Open label extension) – completion July 2014

• Efficacy and safety

Solanezumab: Aβ mid-region IgG1 mAbSolanezumab: Aβ mid-region IgG1 mAb

• Crenezumab; Genentech/AC Immune

• humanized IgG4 Aβ mAb; binds soluble, oligomeric and fibrillar Aβ; inhibits aggregration; disaggregates fibrillar Aβ

Phase I (completed in 2010):

• Safe; no vasogenic edema; 56 AD pts

Phase II (ongoing):

• 372 AD pts; i.v. and s.c.

• Primary endpoint: cognitive and global function

• Completion date: September 2014

Prevention Trial (new):

• 300 Colombian PS1 E280A FAD Kindred

MABT5102A: Aβ IgG4 mAbMABT5102A: Aβ IgG4 mAb

• Hoffmann-LaRoche

• Conformation-specific IgG1 hu mAb; binds N-term then mid-Aβ epitopes; high affinity for fibrillar Aβ

Phase I ended in Sep 2010; 60 AD pts

• PET sub-study showed plaque lowering; MRI VE

Phase II (ongoing):

• 360 prodromal AD pts; subcutaneous injection

• Primary endpoints: CDR-SOB, PET imaging

• Secondary endpoints: ADAS-Cog, safety, pharm

• Completion date is April 2015

Gantenerumab: fully humanized Aβ mAbGantenerumab: fully humanized Aβ mAb

Other Passive Aβ/IVIG IT Clinical TrialsOther Passive Aβ/IVIG IT Clinical Trials

• GSK933776: Phase I complete; Phase I in 35 pt with mild AD or MCI; CSF Aβ w/single dose; Dec 2011; Phase II trial in geographic atrophy secondary to AMD in 162 patients; completion date Mar 2014

• BAN2401: Esai/BioArtic, humanized mAb against Aβ protofibrils; Phase I for safety/tolerability in 80 AD pts; Oct 2012

• Gammagard: Baxter Healthcare; 10% IGIV; Phase III in 390 AD pts; cognitive and global function; Jan 2013

• NewGam: Sutter Healthcare; 10% IVIG; Phase II in 50 MCI pts; Jan 2013

Other IT Therapeutic Targets?Other IT Therapeutic Targets?

• Pyroglutamate-3 Amyloid-β• BACE-1 enzyme• Pathological Tau

What is PyroGlutamate-3 Aβ? What is PyroGlutamate-3 Aβ?

Gunn et al.,Intl J Biochem & Cell Biol, 2010

R1 2

8 2A

ßp

E3

AD: 78 yr male DS: 47 yr male aCtrl: 74 yr male

AβpE3 vs. General Aβ in Human Brain:AβpE3 vs. General Aβ in Human Brain:Frontal Cortex

12/12 AD (ave. 84 yr) 3/3 DS (ave. 49 yr) 7/10 aCtrl (ave. 71 yr)

Mandler et al., J Alz Dis 2011

PyroGlu-3 Aβ in PSD in Early ADPyroGlu-3 Aβ in PSD in Early AD

APPswe/PS1dE9: 14 moAPPswe/PS1dE9: 14 mo

Pilot Study: AβpE3 Passive Pilot Study: AβpE3 Passive Immunization Prevention Trial in MiceImmunization Prevention Trial in Mice

• APPswe/PS1dE9 (C57BL/6) mice

• Start: 6 mo

• End: 14 mo

• Weekly intraperitoneal injections of 200 μg AβpE3-x mAb [n=6 (3M, 3F)] or PBS [n=3 (1M, 2F)]

• Duration: 32 weeks

Frost et al., Neurodegen Dis, 2012

Passive Aβ IT in Mice: PyroGlu-3Aβ mAbPassive Aβ IT in Mice: PyroGlu-3Aβ mAb

Passive IT against BACE1 -VIB, Lilly, J&JPassive IT against BACE1 -VIB, Lilly, J&J

• mAb 1A11 inhibited BACE1 in vitro and in vivo

• Intra HC injection• APPDutch Tg mice

JBC 2011

Passive IT against BACE1 (Genentech)Passive IT against BACE1 (Genentech)

Sci Transl Med, 2011

• High-affinity, phage-derived BACE1 mAb

• Reduces Aβ production in vitro

• Lowers peripheral and CNS Aβ levels in vivo in mice and NHPs

• Highly selective; does not recognize BACE2 or Cathepsin D

Passive Tau IT in Tau Tg Mice (Lilly)Passive Tau IT in Tau Tg Mice (Lilly)

Chai et al., JBC, in press

• PHF-1 and MCI mAbs; prevention in JNPL3 and P301S Tg mice• reduced tau pathology and axonal degeneration• slowed disease progression

Hurdles: Passive IT for ADHurdles: Passive IT for AD

• Frequent dosing & doctor visits; expensive

• Vasogenic edema and MH (Aβ); ~ 40-65% of AD = APO E4

• Getting enough mAb into brain

• BBB integrity

• Anti-idiotypic Ab secondary response

• Which type or conformation? Aβ, tau

• Targeting intracellular proteins (e.g., tau)

• Off-target binding (e.g., anti-oligomer mAb, anti-BACE1)

• Will any of this make a difference in AD pts with established neurodegeneration?

Perrin et al., Nature October 2009

AD Pathogenesis: Amyloid plaque accrual precedes NFTs and cognitive decline

ConclusionsConclusionsCurrent Immunotherapeutic Strategies for AD:• Passive vaccination against Aβ, BACE 1, or Tau

-- avoids immune response-- repeated iv injections monthly; expensive-- evidence for Aβ clearance; microbleeds-- awaiting the results of Phase III clinical trials

• Active vaccination against Aβ-- adverse effects due to T cell response to self-protein-- second generation vaccines include B cell epitopes, DNA vaccines, different routes of administration-- long-lasting; fewer doses; cost-effective for large

at- risk population; need biomarkers -- Currently in Phase I and II trials in humans

• For both: the earlier, the better!

AcknowledgementsAcknowledgements

Center for Neurologic Diseases

J Frost Q ShiB Liu S MatousekK Le J Kenison

Former Lab/CND Members:H FuY PengL JiangJ Sun

Supported by NIH RO1 AG20159 and philanthropic funds.

Probiodrug AG*H DemuthS SchillingM Kleinschmidt

* We are grateful to Probiodrug for providing us with the AβpE3-x mAb