Download Fig.1 NEW PARADIGM HAS FOUR MAJOR THEMES (I)

Toxicogenomics in the USA
- Molecular toxicological approach in drug discovery
and development
- Current use of toxicogenomics in preclinical studies
under assessing the current limitations and future
promise
Pfizer, Global Research & Development
Drug Safety Evaluation
Ikuo HORII
Disease is the outcome of the interaction between genes and environment
Genes
Disease
Environment
Diet
Organs
Gene related Factor
Life-style
Medicines
Most toxicologically relevant
outcomes require differential
expression of multiple genes
Toxicity
Side Effect
directly caused by DNA damage
Critical !!! (Mutagenicity, Carcinogenicity, etc.)
Toxicity indirectly derived from the changes of
related gene expression
Manageable !
Molecular Tox.
Approach
Toxicopanomics
Toxicogenomics
Toxicoproteomics
Metabolomics
Traditional Toxicology for Safety Assessment
Whole body assessment
Regulatory Tox.
Single Admin. Tox.
Repeated Admin. Tox.
Reproduction Tox.
Carcinogeneicity
Gene Tox.
Specific Tox.
etc..
Investigative Tox.
- General observation
(Lethality, Clinical sign, …)
- Body weight, Food consumption
- Clinical Pathology
(Blood chemistry, Hematology,
Urinalysis, …)
- Functional assessment
(Hepatic/Renal, CV, …)
- Histopathology
(Organ wt., Morphology, …)
In Vitro
Alternative
Molecular Toxicology
- New Science
- New Technology
Gene expression and toxicology
Most toxicologically relevant outcomes require
differential expression of multiple genes.
If toxicity manifested at the level of organism is
preceded by altered expression of related genes,
its detection can serve as an early warning for
subsequent deleterious outcomes
Miniaturization and automation of new tools for
analysis of gene expression and metabolic
networking allow the molecular life of cells to be
studied at a more holistic (and complex) level than
was previously possible
Molecular Toxicological Approach for Safety Assessment
Compound
Target site
( Efficacy)
Target site
(Toxicity)
Toxicity
Side Effect
Tox. out of extension of
efficacy
Central nervous
Peripher.nervous
Cardiovascular
Respiratory
Targeted Effect
Toxicological Endpoint
Digestive
Liver/Kidney
Urinary
Endocrine
Tox. on extension of efficacy
Molecular Tox.
Approach
Hematopoietic
Muscle/Skeletal
Skin
Sensory
Pharmacogenomics
Efficacy
Toxicopanomics
Safety
etc.
Change of toxicological approach
Introduction of new technology
IND(Entry into human)
Nos of Compound
Screening
NDA
Cost / Resources
Leads
Molecular-targeting
(Genomics)
Combinatorial Chemistry
SRA/SRT
• Many compounds
• Small amount of comp.
Candidate Compound
HTP-Tox./DMPK
- Molecular tox.
- Cell culture
New analytics
Regulatory Toxicology
- LC/MS/MS
(cassette dose)
HTP-Tox. in vivo
Pilot Tox.
Investigative Tox….
• Molecular-targeted comp.
Molecular Toxicology
Toxicopanomics
+ New Science
Toxicogenomics
Toxicoproteomics
Metabolomics
Safety
Assessment
Study Design for Toxicogenomics/Toxicoproteomics Assessment
Detection
- Gene expression : Gene chip analysis, etc
- Protein synthesis : 2-D Electrophoresis, Protein analysis
Study Design
(Comparison with known toxic-compounds under the database)
In vivo
In vitro
Normal(non-treat) & Treated
Cell / Organ / Tissue
- Non - change
- Up - regulation
- Down - regulation
Data Analysis
Toxicity-related Gene
Database
Archives-database
(Published information)
Significance of Toxicogemonics / Toxicoproteomics Approach
--- Mechanistic investigation & prediction of toxicity --Mechanistic Tox. Study
Study result
- Tox.related gene / protein
- Mechanistic related
metabolic pathway / action site
Tox. Prediction Study
- Expression profile of gene / protein
in new compounds
- Comparison of profiles with existing
gene-related toxicological database
Prediction of Toxicity
( Strategy of drug discovery )
Genes on the toxicology gene chip
Functional group
Stress response
Cell proliferation
Apoptosis
DNA damage
Inflammation
Oxidative stress
Drug metabolism
Transporter
Type of genes
Oncogenes
Acute phase response
Signal transduction
Transcription factors
Cell cycle regulation
Growth factors and receptor
Tumor suppressors
Caspases
Apoptic regulators
DNA repair
DNA morphology
Cytokines
Vasoregulators, etc.
Glutathione metabolism
Oxidase
Protein thioles
Cytochrome P450s
Glutathione transferase
UGT
Organic
Peptide
Ion pumps
Toxicogenomics・Toxicoproteomics・Metabolomics
DNA
：
Genome
(Genomics)
Gene-polymorphism
(SNPs etc)
RNA
：
Transcriptome
(Transcriptomics)
Gene expression profile
(mRNA )
Proteome
(Proteomics)
Protein synthesis profile
(Molecular function)
Protein
：
Biochemicals ： Metabolome
（Metabolites)
(Metabolomics)
Metabolite-pattern profile
(Urine, etc)
Timing of gene expression and protein synthesis
--- Toxicological assessment point ? --Toxicological stimulation(Trigger)
DNA
Signal
ｍRNA
mRNA Level
Toxicogenomics
Appearance of toxicity
Protein
Protein Level
Toxicoproteomics
Metabolic pattern in organism
--- Process from toxicity appearance through damage to restoration ---
Cell injury
20
Metabolic change
in injury site
z
10
Outbreak of injury
0
10
y
Repair of injury
10
x
20
0
liver (steatosis)
Toxicity type & site
heart
Pattern recognition
renal medulla
renal cortex
control
- Combination of changes
- Severity
Pattern analysis
Database
Gene expression, protein synthesis and metabolism in living body
Compound
Phase II Metabolism
m metabolites
t1
Phase I Metabolism
n metabolites
t2
t3
Gene expression
Liver
t1g1, t2g1, t3g1, t1g2, t2g2, t3g2, …...t1gi, t2gi, t3gFn,m
up or down
T1, T2, T3,etc
Blood
Protein synthesis
Ti(t1p1,t2p1,t3p1….tipi )
tx
Toxicological Endpoint
Other organs
General metabolism
Gene regulations etc.
Biochemical changes in bio-fluid / cell / organ
Urine
Metabolomics
Toxicological Endpoint Assessment in Traditional Tox-biomarkers
with New Markers of Toxicogenomics, Toxicoproteomics and Metabolomics
Toxicological Endpoint
Gene expression
(Toxicogenomics)
Protein synthesis
(Toxicoproteomics)
Biochemical changes (bio-fluid, cell, organ) (Metabonomics)
Traditional Toxicological Parameters：Clinical sign, Clinical pathology,
Histopathology, etc.
Safety Database for Tailor-made Medical Treatment
EIH(IND)
Drug
discovery
Lead compound
Clinical
development
Candidate compound
Know - How
Management
Molecular Toxicology
Toxicity / Side-effect
Prediction
Countermeasure
Safety Assessment Tool
Guidance Expert System
Safety Assessment
Database
NDA
Market
Drug
New data
Tailor-made
Medical Treatment
The 2002 Workshop on Pharmacogenetics/Pharmacogenomics
in Drug Development and Regulatory Decision-Making
--- Sponsored jointly the FDA, DruSafe PhRMA and PWG --May 16 - 17, 2002 at the University of Maryland, Shady Grove Conference Center
Toxicogenomics in Drug Development
: Where are we today & where are we going ?
Industry and regulatory agencies viewed this meeting as an opportunity
to discuss how such data should be included/evaluated in IND and NDA
applications.
Where are we now ?
Where would we like to be ?
(1) Is toxicogenomic science and validation technology
sufficiently mature to reply upon genomic data for
safety decisions and to justify the routine use of
genomic data in GLP toxicology studies ?
Current toxicogenomic data is not being collected in
GLP studies, and the data is difficult to interpret and
do not add to standard toxicology assays.
However, genomic data is useful in mechanistic
studies, and if done with IND compounds, the data
should be submitted. There was some consensus
that genomic data may be added to standard
toxicology data, but we need to explore the “safe
harbor” concept with FDA.
(2) Where is the value of toxicogenomic data to
Industry and the FDA ?
The value of toxicogenomic data now is in
mechanistic studies and hypothesis testing and
not predictive data in risk assessment.
Most would like to develop more confidence in
data, share data with FDA.
(3) How could data from genomic arrays, in conjunction
with standard short-term toxicology studies, be used
to assist in study design or in species selection for
long-term toxicology studies ?
The toxicogenomics is not well understood presently
to be predictive, especially outside the rat/mouse
species, of the human response.
The standard toxicology studies need not include or
be replaced by genomics, but genomic data may be
used to better design of toxicology.
(4) Is there a need for guidance in the toxicogenomics
area ? If guidance’s existed what wold be their main
purpose and what would be the potential impact ?
A regulatory guidance document is not necessary at
this time. However, standard practice for reviewing
data needs to be made transparent and a consensus
of how data should be submitted would be useful.
Thus, a white paper on how to review genomic data,
within FDA, for internal consistency is recommended.
(5) Development of “historic databases” in interpreting
toxicogenomic findings may be useful if the data are
robust and reliable and if toxicogenomics profiles
predict toxicities.
If this is correct, how should such databases be
developed and utilized ?
The development of some form of knowledge base
rather than a historical database for interpreting
toxicogenomic findings.
Since the technology is emerging, and data is
limited, the potential of genomic data is a “red flag”
awareness to evaluate in other toxicological
assays.
As a conclusion,
The application of toxicogenomics disciplines
ranges from hypothesis testing of toxicity to
safety evaluation.
However, validation of the results for use in
registration and marketing is limited and can
only be evaluated on a case by case basis at the
present time.
As we progress, the regulatory implications of
toxicogenomic data will be transparent and lead
to relevant guidance documents.