Informatics and drug discovery
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Informatics and Drug Discovery. Peter Goodfellow. 20 th Century Health Achievements. Vaccination Control of infectious diseases Decline in deaths from coronary heart disease and stroke Family planning Healthier mothers and babies Fluoridation of drinking water

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Informatics and Drug Discovery

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Informatics and drug discovery

Informatics and Drug Discovery

Peter Goodfellow


20 th century health achievements

20th Century Health Achievements

  • Vaccination

  • Control of infectious diseases

  • Decline in deaths from coronary heart disease and stroke

  • Family planning

  • Healthier mothers and babies

  • Fluoridation of drinking water

  • Safer and healthier foods

  • Recognition of tobacco use as a health hazard

  • Motor vehicle safety

  • Safer workplaces

    Source: CDC MMWR April 02, 1999 / 48(12);241-243 http://www.cdc.gov/mmwr/preview/mmwrhtml/00056796.htm


Aids mortality and protease inhibitor use

AIDS Mortality and Protease Inhibitor Use

Deaths

Deaths per 100 person-years

Therapy with a PI (% of patient-days)

Use of protease inhibitors

1994

1995

1996

1997

1998

Year

Palella et al. N Engl J Med 1998


Drug discovery

Drug Discovery

Output of New Molecular Entities

120

100

Index (% of 1994 output)

80

60

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

Year

Source: CMR International


Informatics and drug discovery

chemicaldiversity

proteintargets

identify‘hit’

optimize‘hit’ structure

database

/genes

test safety/efficacy

animals

humans

The Drug Discovery Process

The aim is to translate new information into new therapies


Complexity of drug discovery finding a molecule that satisfies multiple criteria

Complexity of Drug DiscoveryFinding a Molecule that Satisfies Multiple Criteria

1 Drug Molecule

manufacturable

patentable

non-mutagenic

non-teratogenic

durable

reversible

non-inducing

metabolically stable

permeable

soluble

physically stable

potent

10,000 Drug Candidates

selective

Valid Biomedical Hypothesis?

targeted


Complexity of drug discovery finding a molecule that satisfies multiple criteria1

Complexity of Drug DiscoveryFinding a Molecule that Satisfies Multiple Criteria

1 Drug Launch

Regulatory filing

Competitive profile

Cost-effective manufacturing

Carcinogenicity studies

Long-term safety

Efficacy

Side effect profile

Dosing ranges

Patient recruitment

Trial sites and investigators

Stability

Formulation

10 Drug Molecules

Safe and active in lab and animal models

All discovery criteria met


Predictive models

Predictive Models

  • A predictive model quantitatively relates a number of descriptors (variable factors that are likely to influence future behaviour or results) to an outcome.

    • In marketing, for example, a customer's gender, age, and purchase history (descriptors) might predict the likelihood of a future sale (outcome).

  • In drug discovery, descriptors tend to be derived from chemical structure, and outcomes are in vitro or in vivo phenomena

    • the goal is to predict behaviour before synthesis

    • models can be built from experimental data too:

      • e.g. prediction of %F from solubility, permeability and clearance data


Statistics

Statistics

  • Various statistical methods are applied to find the mathematical relationship between the descriptors and the outcomes

    • multiple linear regression, logistic regression K-nearest neighbours, PLS, linear discriminant analysis, decision trees, neural networks, Support Vector machines and many more

    • Choice depends on

      • data type/volume

      • the objectives for the model (see later)

      • personal preference


Modelling decisions

Modelling Decisions

  • Model in vivo or an in vitro surrogate?

    • in vivo ideal, but often limited data set

    • in vitro is itself a model for in vivo

      • but data generation is easier

    • E.g. Absorption

      • Caco-2 cell in vitro data vs in vivo perfusion data

  • Use of data

    • Is the data good enough to be left as “real” numbers e.g. pIC50?

    • Or should it be used as a category e.g. “high, medium, low”?

  • Do you want to filter “bad”, prioritise “good” or both?

    • Do you need to avoid false positives or negatives?

      • One is usually more important than the other


Uses of predictive models in discovery

Uses of Predictive Models in Discovery

  • Lead generation

    • Filtering of structures to remove poor start points from screening collection

      • “Lipinski’s rules”, sub-structure filters, hard to remove or critical properties like poor solubility, permeability and hERG interaction

        • Even 70% predictive models are useful, as they can enrich the proportion of “good” compounds coming in

  • Hit to candidate

    • Used to guide medicinal optimisation

      • Predictive power and interpretability are key

        • Interpretability can often compensate for poor predictive power, as gives insights to the chemists as to what might solve the problem

  • Candidate attrition

    • Predictive ADMET used as another component of “risk assessment” for taking a candidate forward, to aid formulation studies, or to help interpret the result of an experiment


Modelling retention times on hplc

Modelling Retention Times on HPLC

Q. Given about half a million good quality retention times and chemical structures, can we build a model of retention time that would be of use?

Pred. RT

Mean Absolute error = 0.23 mini.e. 14 seconds

Abs. Error

Exptl. RT

Chris Luscombe CIX


Informatics and drug discovery

Initial Filter from a Developability AssayInterpretable rule, filters “bad” compounds, with low false positive rate

143/160 compounds

in the box are active


Deep detecting adverse events

DEEP – Detecting Adverse Events

Systems for Signal Detection

DEEP Partnership with Lincoln Technologies

This system has now been deployed at FDA, CDC,large Pharma (Pfizer, Lilly, Bayer, BMS, J&J, Roche, AZ)

DEEP

DEEP (Data Explorationand Evaluation in Pharmacovigilance)

Scientific PublicationsNew strategies to evaluate poly-therapy, drug interactions and demographic “risk factors” for AEs


Safety data mining enables rapid and systematic identification of safety signals

Safety Data Mining Enables Rapid and Systematic Identification of Safety Signals

With post-marketing data, it is difficult to distinguish signals from noise.

Safety Data Mining (SDM)/disproportionality methods identify AEs that are reported with > expected frequency (statistical independence)

Frequency is assessed against the background of all other drugsand events. Results are used for hypothesis generation.

Bayesian methodology to estimate relative reporting rates (risks) of AEs

Enhanced effectiveness of post-marketing pharmacovigilance through rapid, systematic screening of AE databases

Enhanced benefit-risk management


Bayesian methods to assess the frequency of specific drug adverse event combinations

Bayesian Methods to Assess the Frequency of Specific Drug-Adverse Event Combinations

Drug X

All other Drugs

Event of interest

C

A

All other Events

D

B

An empirical Bayesian methodology estimates relative reporting rates

Is A>C ??

A+B C+D


Interpretation

Interpretation

Wonderex - Rash (16 reports in the database)

  • EBGM: 3.0 EB05: 1.8 EB95: 4.3

  • Wonderex-rash combination is reported at 3-fold greater frequency than if there were no association between Wonderex and rash

  • 95% confidence that the true relative reporting rate is at least 1.8

  • 95% confidence that the true relative reporting rate does not exceed 4.3


Informatics and drug discovery

0 EB05  1 < EB05 2 < EB05 4 < EB05 8 < EB05 < 

Enhanced Pharmacovigilance

Had these tools previously been available, critical signalsmight have been identified years before they were recognized with traditional pharmacovigilance. They are now used routinely .


Deep provides information to reconise product performance and benefit risk ratio

Benefit-risk management-Pharmacovigilance planning

Competitive intelligence

Regulatory agency queries

Regulatory submissions for PLEs

Characterizing factors associated with rare serious AEs

In-licensing due-diligence

Exploring drug interactions and polytherapy in ‘real world use’

Understanding the effects of litigation/publicity on safety signals

Evaluating indication-specific safety profiles in products with multiple indications

Evaluating rare serious events in special populations (i.e., children)

Signal assessment for our co-licensed products

Advisory committee preparation

DEEP Provides Information to Reconise Product Performance and Benefit-Risk Ratio:


Informatics and drug discovery

NSAIDS & COX-2 Inhibitors:

AERS to 3Q03(Suspect drugs)


Informatics and drug discovery

AERS to 3Q03 (Suspect drugs)


Cardiovascular and stroke related aes subset analysis age 50 yr

Cardiovascular and Stroke-Related-AEs Subset Analysis: Age < 50 yr

AERS through 3Q 2003


Informatics and drug discovery

Chemical Safety:

Using human safety data to determine which structural features of drugs contribute to their toxicities

Identify associations between fragments and signals,by calculating diagnostictest statistics.

A positive signal (EB05  5 ) is used as the ”gold standard.” The presenceof a fragment in drug represents a “positive test.”

Identify drug-event pairs with EB055(designate as "signals").

Run datamining algorithm (MGPS).

Create a chemical fragment library for all drug structures in AERS using MoSS to create fragments ranging in size from 4-10 atoms.

Diagnostic test statistics

For a given fragment-event pair:

Odds ratio of 20 means that the odds of having a specific "signal" are 20 times greater if the fragment is present (in the molecule) than if it is not

Positive predictive value of 0.4 means that 40% of drugs containing the fragment will have a “signal” for that adverse event


Informatics and drug discovery

= nitrogen


Thanks to

Thanks to:

  • Darren Green, John Leonard, June Almenoff and Trevor Gibbs for sharing slides

  • Colleagues who taught me about drug discovery

  • SB and GSK for letting me play with a very big chemistry set


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