dementias advances in treatment
TRANSCRIPT
Update on biological treatments for dementia
Professor Roy Jones
RICE (The Research Institute
for the Care of Older People),
Royal United Hospital, Bath;
University of Bath;
University of Bristol
Disclosures
I serve on scientific advisory boards and receive honoraria for lectures and chairing symposia for major pharmaceutical and other companies involved in research to find treatments for Alzheimer’s disease and related conditions .
The research institute also receives research support grants from various Pharmaceutical or Biotech companies, the NIHR and charitable foundations
Research to find new treatments
Since 1987 we have been involved at RICE in studies
of more than 50 compounds for the potential treatment
of dementia (mainly Alzheimer’s disease) and memory
impairment
Five drugs have been licensed, four of which are still in
use and available in the UK, and all were studied in
clinical trials at RICE
No new drugs have been marketed since 2002 and
more that 120 drugs have failed to post positive results
in phase III late-stage trials
Drugs for Alzheimer’s disease
Cholinesterase inhibitors (acts on acetyl choline)
[ Tacrine (Cognex) — 1993 ]
Donepezil (Aricept) — 1997
Rivastigmine (Exelon) — 1998
Galantamine (Reminyl) — 2000
NMDA receptor antagonist (acts on glutamate)
Memantine (Ebixa) — 2002
2016: another year of disappointments
The disappointing:idalopirdine (Lundbeck/Otsuka)
5-HT6 serotonin receptor antagonist for add on therapy to
cholinesterase inhibitors
Phase III trial (STARSHINE) in mild to moderate AD added to
donepezil did not meet primary or secondary endpoints but
safe and well tolerated (September 2016)
Two similar phase III trials (STARBEAM and STARBRIGHT)
just completed
Press release (yesterday): the 3 studies failed to
demonstrate efficacy (as observed in the positive clinical
phase II study) sufficient to support a regulatory submission.
Lundbeck’s share price “dived”.
(Pfizer’s 5-HT6 receptor antagonist PF-05212377 also failed last
year so this approach may not be effective)
The pathological cascade in ADOverproduction of Aβ
Abnormal APP metabolismReduced Aβ clearance
Ageing
Unknown factors
AD-mutations(APP, PS1, PS2 genes)
Risk-genes(apolipoprotein E) Amyloid-β
accumulation
Activation of neurotoxic cascadesDecreased neurotrophic support
Fibrillary AβAβ oligomers
Hyperphosphorylation of tau
Amyloid plaques
Neuritic plaques
Dementia
Synaptic dysfunctionAxonal dysfunction
Collapse of cytoskeleton
Neurofibrillary tangles
Glial activationInflammation
Oxidative stressMitochondrial dysfunction
Adapted from Forlenza O, et al. BMC Medicine 2010; 8: 89.
The disappointing: amyloid immunisation
Solanezumab (Eli Lilly)– Issues of efficacy in 2 similar studies (EXPEDITION 1 and 2) but
reanalysis (both by Lilly and independently) of combined data
from the studies suggested a 34% effect on cognition in milder
patients (patients not confirmed as amyloid positive)
– Further study (EXPEDITION 3) in 2100 patients with mild AD
and confirmed as amyloid positive (Florbetapir PET scan or CSF
analysis) finished last year
Results announced November 2016. Unfortunately the
study was negative and although there were trends in
both primary cognitive and secondary endpoints the
effects were small and Lilly will not seek approval for the
drug in mild AD (some pre-dementia studies may still
proceed)
The irresponsible!Anti-tau therapy:LMTM (TauRx)
LMTM is a reduced form of methylene blue: it and related
compounds have been in clinical trials for some years (with a
proposed mechanism that blocks tau hyperphosphorylation)
In 2016 three trials (2 in AD and 1 in FTD) reported negative results
The UK company press release led on a purported benefit in a sub-
group (of unstated size) which suggested the drug had positive
results but only in participants not receiving standard AChEI therapy
Immediately after this one of our patients refused to start donepezil
“to wait for this better drug that won’t work if you’re on a current drug”
The company have carried out a “cohort analysis” (not based on the
randomised data) that shows an apparent effect of active AND
placebo (a low 4mg dose of drug given to try and mask unblinding
because the drug turns urine blue) in those not on AChEI therapy
This comparison has been called at best, wrong and at worst, bogus
What can we learn from these and other failures?
Why the failure with solanezumab?
Wrong dose: dose finding for trials was limited and based on
plasma data. Dose may be too low (? could be increased in
ongoing studies with solanezumab in preclinical AD). Future
dose finding likely to be based on CSF exposure and kinetics
The Aβ bound in plasma may actually get into the brain with the
drug
Subjects in Expedition 3 may have had a heavier amyloid load
than Expedition 1 and 2 due to amyloid PET scan positivity
being determined visually
Worth analysing individual patient data for level of amyloid load
and efficacy
The drug targets the wrong type of amyloid or needs to be
given even earlier or the amyloid hypothesis is wrong or
insufficient for therapeutic success
Development of better animal models of Alzheimer’s disease
The pathological cascade in ADOverproduction of Aβ
Abnormal APP metabolismReduced Aβ clearance
Ageing
Unknown factors
AD-mutations(APP, PS1, PS2 genes)
Risk-genes(apolipoprotein E/TREM2) Amyloid-β
accumulation
Activation of neurotoxic cascadesDecreased neurotrophic support
Fibrillary AβAβ oligomers
Hyperphosphorylation of tau
Amyloid plaques
Neuritic plaques
Dementia
Synaptic dysfunctionAxonal dysfunction
Collapse of cytoskeleton
Neurofibrillary tangles
Glial activationInflammation
Oxidative stressMitochondrial dysfunction
Adapted from Forlenza O, et al. BMC Medicine 2010; 8: 89.
The pathological cascade in ADOverproduction of Aβ
Abnormal APP metabolismReduced Aβ clearance
Ageing
Unknown factors
AD-mutations(APP, PS1, PS2 genes)
Risk-genes(apolipoprotein E/TREM2) Amyloid-β
accumulation
Activation of neurotoxic cascadesDecreased neurotrophic support
Fibrillary AβAβ oligomers
Hyperphosphorylation of tau
Amyloid plaques
Neuritic plaques
Dementia
Synaptic dysfunctionAxonal dysfunction
Collapse of cytoskeleton
Neurofibrillary tangles
Glial activationInflammation
Oxidative stressMitochondrial dysfunction
Adapted from Forlenza O, et al. BMC Medicine 2010; 8: 89.
Development of improved mouse models of AD(MODEL-AD)
In January 2017, the US National Institute of Aging
(NIA) funded a 5-year $25m dollar programme to
generate and characterise mouse models using late-
onset AD genetic variants that most faithfully
represent human disease
Aim to develop 8 models/year and going beyond
amyloid and tau
Starting with apoE4 and R47H variant of TREM2,
then add for example microglial transporter ABCA7
and immune gene interleukin-1 receptor accessory
protein (IL1RAP)
Models will be freely available
MODEL-AD: Model Organism Development & Evaluation for late-onset AD
Alzheimer’s disease occurs on a continuum of severity from
No (Alz disease)Mild (Alz disease)Marked impairment (Alz dementia)
*MCI = Mild Cognitive Impairment due to AD or Prodromal AD
% of end-stage AD
100
60
20
0
80
40
40 50 7060 80
Asymptomatic(pre-clinical)
phase
Symptomatic(pre-dementia)
phase
Dementiaphase
Onsetof MCI*
Clinical diagnosisof AD
Estimated start of amyloid deposition
Age (years)
Degree of cognitive
impairment
AD Diagnosis Marching Leftward
Standard
diagnosis
Dubois
research criteria:
“early AD”
Modified
Dubois criteria:
“earlier AD”
Presymptomatic
AD
No symptoms,
biomarker
evidence
of amyloid
dysregulation
Very mild
symptoms
+ amyloid
biomarker
Episodic
memory
impairment
+ any
biomarker
Dementia
Onset of ADpath
Courtesy of B Winblad From Aisen PS. Alzheimers Res Ther. 2009
Do biomarkers help?
Amyloid protein is reduced and total tau and p-tau are increased in CSF in AD
Sunderland et al. JAMA 2003; 289: 2094–2103
CSF -amyloid1-42 CSF tau
Alzheimer’s disease
(n=131)
Alzheimer’s disease
(n=131)
Controls
(n=72)
Controls
(n=72)
pg
/ml
pg
/ml
CSF – cerebrospinal fluid
Issues with biomarkers
Availability and expense of MRI and PET scanners and
amyloid imaging agents (and scans may need to be
repeated)
Need for CSF testing (and may need to be repeated)
Standardising CSF biomarkers has improved and is
likely to become more widely used
Acceptance by regulators of biomarker data in
registration of new drugs (seems more likely especially
for FDA in US)
If drugs are registered using biomarkers, will this
restrict their prescription only to patients who have had
biomarkers measured?
Treatment of Alzheimer’s disease
166 people with prodromal or mild AD, recruited from a number of centresFurther larger studies are ongoing including at RICE
Sevigny J et al, Nature 2016, 537, 50-56
Aducanumab update
Initially 1,3,& 10mg/kg studied but high adverse effects at
10 so 6mg/kg added and reduced amyloid (florbetapir
PET) at 1 year
ARIA-E (oedema) common and increased with dose and
apoE4 status (5% 1&3, 43% 6 and 55% 10 for carriers,
9% 3, 22% 6, 17% 10): discontinuation low & 56%
continued, some at a lower dose. 89% occur early in
treatment and one third asymptomatic
Two phase III studies in progress in mildly symptomatic
patients
AD Secondary Prevention Studies
• API (Alzheimer’s Prevention Initiative): $100m prevention trial
of outwardly healthy people at high genetic risk of AD using
antibody crenezumab (Genentech) – large Columbian kindred
and those with familial AD mutations from US
• DIAN (Dominantly Inherited Alzheimer Network) using
gantenerumab, solanezumab & BACE inhibitor in 160 people
aged 30+ with FAD mutation from US, UK, Australia, Spain
and Germany
• A4 (Anti Amyloid in Asymptomatic AD) - a trial of those who
are amyloid biomarker positive
• Positive results from these studies will provide support for the
amyloid hypothesis
AAmyloid Protein
-Amyloid Deposits
Beta Secretase Gamma Secretase
Beta Amyloid Peptide A
A-peptide Production
Beta Amyloid Fibrils
A
Passive immunisation
Active immunisation
Prevent amyloid
aggregation
Secretase Inhibitors
-secretase (BACE-1) inhibitors
Verubecestat (MK8931;BACE1 inhibitor)
– phase II/III study (EPOCH) in 1960 subjects with mild to
moderate AD. Safety cohort of 200 treated for at least 3
months completed 2013 and study allowed to continue –
main results ?2017/8.
– APECS trial in amnestic Mild Cognitive Impairment due to AD
(n=1500) results due 2019
E2609 (Eisai/Biogen; BACE-1 inhibitor) – phase III
studies in early AD (FDA Fast Track Status)
Others include HPP854 (High Point Pharmaceuticals,
ph1 MCI/mild AD), RG7129 (Roche, ph1); AZD3293
(Astra Zeneca, phase 1)
The pathological cascade in ADOverproduction of Aβ
Abnormal APP metabolismReduced Aβ clearance
Ageing
Unknown factors
AD-mutations(APP, PS1, PS2 genes)
Risk-genes(apolipoprotein E) Amyloid-β
accumulation
Activation of neurotoxic cascadesDecreased neurotrophic support
Fibrillary AβAβ oligomers
Hyperphosphorylation of tau
Amyloid plaques
Neuritic plaques
Dementia
Synaptic dysfunctionAxonal dysfunction
Collapse of cytoskeleton
Neurofibrillary tangles
Glial activationInflammation
Oxidative stressMitochondrial dysfunction
Adapted from Forlenza O, et al. BMC Medicine 2010; 8: 89.
Anti-tangle (anti-tau) approaches to therapy
Increasing interest in anti-tau treatments since tau (and tau
PET imaging) reflects the state of a person’s disease and
cognition more than amyloid
Altering or blocking tau hyperphosphorylation
– Unsuccessful so far
Enhancing clearance of aggregates with antibodies or
drugs
– Tau is a potential target for active or passive immunotherapy and
data from mice supports this approach
– A number of immunisations targeting tau have now entered
early clinical trials (eg current phase I study at RICE with
ACImmune’s active antibody will complete this year)
RVT-101(Inteperdine; Axovant)
5-HT6 serotonin receptor antagonist (like 2
recently failed compounds)
3 studies in AD, DLB & Parkinson’s disease
dementia (PDD)
– MINDSET: 6 month phase 3 study in AD added to
stable donepezil therapy measuring cognition and
ADLs
– HEADWAY: phase 2 study in DLB with global
primary measure and hallucinations as secondary
– October 2016: small 3 month study in AD, DLB
and PDD looking at effects on gait
Slide of Professor Clive Holmes
Xanamem (Actinogen, Australian company) blocks
enzyme that activates cortisone into active ‘stress
hormone’ cortisol, which is very active in hippocampus
and frontal cortex.
XanADu phase II study in mild AD about to start
40mg daily of pimavanserin a
selective 5HT2A partial inverse
agonist was well tolerated over 6
weeks of treatment
After solanezumab: where should Alzheimer’s research go?
(see www.alzforum.org/news/
Slide of Professor Clive Holmes
http://www.alzforum.org/news/conference-coverage/aruk-roundtable-where-now-alzheimers-disease-research
Image courtesy of Howard Fillit, ADDF
The future?
• Understand more about oligomeric Aβ
• Look at pathways from the new genetic approaches such as GWAS
(as in US MODEL-AD mouse model development)
• Tau clearly has a central role in Aβ neurotoxicity and needs further
investigation
• Consider multiple pathologies beyond amyloid and tau that are in
the AD brain early on – hypertension, diabetes, inflammatory
disease, Lewy bodies, hippocampal sclerosis, TDP43 deposits,
vascular disease
• Consider 2 or more approaches in combination
• Consider adaptive clinical trial designs
• Improve trial efficiency, combine phases of development, enable early
stopping, test candidate drugs in parallel etc
• European Prevention of Alzheimer’s Dementia (EPAD) will use this to
test treatment in the pre-symptomatic phase (proof of concept trials)
1
Goal 1: Prevent and effectively treat
Alzheimer’s disease by 2025
If this is to be achieved by finding a
suitable drug treatment, then that
drug should already be in Phase II
testing!
Thank you