Download Autoimmunity: relative risks

Changing the trajectory of
drug R&D
Robert Plenge, MD, PhD
American College of Rheumatology
November 15, 2016
Disclaimer
I am a full-time employee at Merck
Our two fundamental challenges
Cost to develop an
asset has increased by
Average peak sales
per asset has halved
1/3rd since 2010
since 2010
Where things go wrong & what that costs
$$$
Paul et al NRDD 2010
About 1 out of 10
programs make it
to launch
Where things go wrong & what that costs
$$$
But critical phase is
choice of target and early
development
Paul et al NRDD 2010
About 1 out of 10
programs make it
to launch
We relied on preclinical models to pick targets and
estimate efficacy in heterogeneous human populations
It was…
Discovery
(new targets)
Optimization
(pre-clinical)
Early Development
Today, humans are the model organism of
choice for new targets and precision medicine
Discovery
(new targets)
Optimization
(pre-clinical)
Early Development
Human genetics is a powerful tool to establish
Science
Medicine, July 2016
“causal human biology” at
theTranslational
very beginning
First, an example from
cardiovascular disease
There are examples of human genetics
leading to new drug targets (PCSK9)
Many genes influence cholesterol levels and
risk of heart disease
Atherosclerotic
Plaque
PCSK9 mutations associated with high and low
LDL cholesterol levels (and heart disease risk)
Blood Flow
…and design studies to find drugs that fix the underlying molecular defects – for example,
blocking PCSK9 lowers LDL (or “bad”) cholesterol in the blood.
PCSK9
LDLR
LDL-C
mAb
LDLR
Recycling
Lysosome
Now, examples from
osteoporosis and
rheumatoid arthritis
A quick primer on genetics of
osteoporosis and related traits
• >100 common variants associated with
osteoporosis
• Additional genes mutated in rare forms of
bone mass loss / accrual
• Experimental studies determine function,
including gain- vs loss-of-function of risk allele
• While many genes implicated, only a few
have led to novel therapies
David Karasik et al NRR 2016
Teriparatide
- recombinant PTH
- approved
Romosozumab
- anti-sclerostin
- phase III
osteoblast
Denosumab
- anti-RANKL
- approved
Estrada et al NG 2012
A very similar story in RA
• >100 common variants associated with
rheumatoid arthritis
• Additional genes mutated in rare forms of
immunodeficiency or autoinflammation
• Experimental studies determine function,
including gain- vs loss-of-function of risk allele
• While many genes implicated, only a few
overlap with approved therapies or those in
early development
Okada et al Nature 2013
PADI4
- Small molecule inhibitor
- early development
abatacept
- CTLA4-Ig
- approved
tocilizumab
- anti-IL6R
- approved
TYK2
- Small molecule inhibitor
- early development
Smolen et al Lancet 2016
Most are retrospective
examples…what is a
prospective approach to new
targets?
Human Phenotype
Pick a human
phenotype for drug
efficacy
High
Low
LOF
GOF
Plenge et al NRDD 2013
Gene function
Human Phenotype
Pick a human
phenotype for drug
efficacy
High
Low
LOF
GOF
Gene function
Nelson et al NG 2015
Human Phenotype
Pick a human
phenotype for drug
efficacy
High
Low
LOF
GOF
Gene function
Okada et al Nature 2013
Human Phenotype
Pick a human
phenotype for drug
efficacy
X
X
High
X
X
X
X
Identify a series of
alleles with range of
effect sizes in humans
(but of unknown
function)
X
Low
LOF
GOF
Gene function
Pick a human
phenotype for drug
efficacy
Human Phenotype
Efficacy
X
X
High
X
X
X
X
Assess biological
function of alleles
to estimate
“efficacy” response
curve
X
Low
LOF
GOF
Gene function
New target for
drug screen!
Pick a human
phenotype for drug
efficacy
Human Phenotype
Efficacy
X
High
X
X
X
X
Toxicity
X
Assess biological
function of alleles
Assess pleiotropy
to estimate
as proxy for ADEs
“efficacy” response
curve
This provides evidence
for the therapeutic
window at the time of
target ID & validation.
X
Low
LOF
GOF
Gene function
RANK-RANKL and denosumab
Osteoporosis
Pick a human
phenotype for drug
efficacy
High bone
density
Rare variants & osteopetrosis
Common
variants & BMD,
fracture risk
X
X
X
X
Low bone
density
GOF
Rare RANK variants & Paget’s
disease (no known GoF
mutations in RANKL)
X
Efficacy
X
Toxicity
X
Assess pleiotropy
as proxy for ADEs
This provides evidence
for the therapeutic
window at the time of
target ID & validation.
LOF
Gene function
RANK-RANKL and denosumab
Osteoporosis
Pick a human
phenotype for drug
efficacy
High bone
density
Rare variants & osteopetrosis
Common
variants & BMD,
fracture risk
GOF
Rare RANK variants & Paget’s
disease (no known GoF
mutations in RANKL)
X
Toxicity
X
No “obvious”
pleiotropic effects
that could be ADEs
X
X
X
X
Low bone
density
Efficacy
X
This provides evidence
for the therapeutic
window at the time of
target ID & validation.
LOF
Gene function
Allele that protects
from RA is
associated with lossof-function (LoF)
Same LoF allele
has no obvious
increased risk of
infection
Therapeutic hypothesis:
Inhibiting TYK2 will protect from
RA without risk of infection
Tokarski et al JBC 2015
But (and there is always a
but…)
Limitations of the approach
• Not all successful drugs will have genetic
support
– Little direct genetic evidence for TNF as a target
– Other approaches to causal human biology
• Even those targets with genetic support may
fail in clinical development
– Cathepsin K (CTSK) mutations cause
pycnodysostosis
– Odanacatib failed in Phase III due to safety
Introducing novel therapies is an important
component of our future health care system…
…but we need to do more to deliver
affordable medicines that matter
Questions?
@rplenge