Proof of Concept - szucs.ch · Prof. Karl G. Hofbauer. Chair for Applied Pharmacology. Biozentrum / Pharmazentrum. University of Basel. Zürich, 25.09.2007. Proof of Concept

Prof. Karl G. Hofbauer

Chair for Applied Pharmacology

Biozentrum / PharmazentrumUniversity of Basel

Zürich, 25.09.2007

Proof of Concept

The „Message in a Bottle“- Approach to Drug Discovery

New compound

Medicinal chemistry

Broad screening

New compound

Medicinal chemistry

Broad screening

The „Message in a Bottle“- Approach to Drug Discovery

Indication

New compound

Broad screening

Selection Criteria for a Development Compound

Pharmacodynamicse.g. Efficacy, selectivity

Physicochemical propertiese.g. Solubility, molecular size

Pharmacokineticse.g. Bioavailability, half-life

Tolerabilitye.g. Toxicity, mutagenicity

Technical feasibilitye.g. Patentability, manufacturing costs

Marketing aspectse.g. Treatment costs, medical need

Productivity - Expenditure (US Data)R

esea

rch

Exp

endi

ure

(US

$)

New

Reg

istr

atio

ns(N

CE

s)

1985 1990 1995 2000

approx. 60 NCEs*)

approx. 40 NCEsapprox. 7 billion US $

> 40 billion US $

*) NCE, new chemical entity

From “Preclinical Research“ to “Drug Discovery“

Preclinical ResearchIdeas

Concepts

Drug DiscoveryTargets

Processes

Modern Technologies in Drug Discovery

Disease genes & proteins

PhysiologyPathophysiology

Molecular Targets

(>1.000?)

DNA Arrays

Proteome

Antisenseoligonucleotides

Modelorganisms

HumanGenome

(<30.000 Genes)

InformaticsGACCGT

Informatics

500 1000 1500 2000 M/zRel

ativ

e A

bund

ance

(x10

6 )

Mass Spectrometry

Genome

Physiome

Sequencing,Structural analysis

siRNA

From “Clinical Research“ to “Drug Development“

Clinical ResearchBroad Scope

Flexible Study Design

Drug DevelopmentTarget Product Profile

Registration Requirements

Pre-clinical

Drug Discovery & Development

Phase I Phase II Phase III Market

3-5 years 7-12 years life-cycle

Clinical

D0 D1 D2 D3

Target selected,Assay established

Start screening,Search for hits, Selection of lead structures

Optimization of lead structures, Development candidate selected

Hypothesis,Exploratory and basicresearch,Identification of targets

Preclinical Phases

D4

Preclinical development

D0 D1 D2 D3


Optimization of lead structures, Development candidate selected

Lead Optimization

D4


Hypothesis,Exploratory and basicresearch,Identification of targets


D2 D3

Selectivity,In vitro efficacy

In vivo efficacy, disease models,Second species, structure- activity relationship (SAR)

Lead Optimization: Efficacy

D4

Chronic in vivo studies, Further profiling, etc.

Hit to lead Lead optimization Development candidate

D2 D3

Preliminary ADME*),Physical chemistry

ADME, second species PK+)

Physical chemistry,Cytotoxicity, genotoxicity

Lead Optimization: PK/Toxicology

D4

GLP**) toxicology (in vivo toxicology in two species),Safety pharmacology

*) ADME: absorption, distribution, metabolism, excretion

Hit to lead Lead optimization Development candidate

**) GLP, good laboratory practice+) PK, pharmacokinetics

Lead Optimization: ObjectivesOptimal Pharmacodynamics

Appropriate Pharmakokinetics

Affinity and selectivity in vitro, Efficacy in vivo

Bioavailability, half-life,Metabolism, excretion

Minimal ToxicityCyto- & genotoxicity (exclusion criteria)Target organ toxicity (risk assessment)

Lead Optimization: FlowchartNew compound

Further profiling

Receptor binding assay

Cellular assay

In vivo experiment ED50 < 10 mg/kg p.o.

EC50 < 10 nmol/l

EC50 < 100 nmol/l

EC50 , 50% effective concentration ED50 , 50% effective dose

stop

stop

stop

Lead Optimization

Synthesis SAR/STR*Testing

in vitro

in vivo

* SAR, structure-activity relationship; STR, structure-toxicity relationship

Compound (Cpd) Number vs. Cost

> 100,000

1000

10

< 5

1

New cpds

Hits

Leads

Development cpds

Marketed cpds

100

100,000

10 Mio

50 Mio

> 500 Mio

Cost (US $)Number (n)

Success Rate in Clinical Development (US Data)

Phase I LaunchPhase IIIPhase II100

75

50

25

01994 1996 1998 1994 1996 1998 1994 1996 1998 1994 1996 1998

From: Wood, A.J.J., New Engl. J. Med. 355, 618-623 (2006)

Succ

essR

ate

(%)

Year of entry in development phase

Reasons for AttritionA

ttriti

onfo

reac

hcr

iteri

on(%

)

19912000

Clinical safety

Efficacy

Formulation

Pharmacokinetics

Commercial

Toxicology

Cost of Goods

Other

From: Kola, I. & Landis, J., Nature Reviews / Drug Discovery 3, 711-715 (2004)

D0 D1 D2 D3



Optimisation of lead structures, Development candidate selected

Hypothesis,Exploratory and basicresearch,Target identification

Preclinical Proof of Concept (POC)

D4


Preclinical POC

Pre-clinical

Clinical Proof of Concept (POC)

Phase I Phase II Phase III Market

3-5 years 7-12 years life-cycle

Clinical

Clinical POC

Proof of Concept

> 100,000

1000

10

< 5

1

New cpds

Hits

Leads

Development cpds

Marketed cpds

100

100,000

10 Mio

50 Mio

> 500 Mio

Cost (US $)Number (n)

Preclinical POC

Clinical POC

Definition Demonstration of the feasibility of a project

CriteriaPharmacodynamics (mechanism of action, efficacy)Therapeutic relevance (efficacy, surrogate markers)

ObjectivesDefinition of development strategyEarly elimination of potential failures

Proof of Concept

NecrosisHealthy tissue

Coronary artery

Pathophysiology of Myocardial Infarction

Thrombus Artery

Plaque

Compensation:

Neurohumoralactivation

(e.g.: Angiotensin II)

Dose-Response Curve100

50

0

2.5 5 10 20 40 80 160

For

mat

ion

of a

ngio

tens

inII

(%)

Angiotensin Converting Enzyme (ACE) inhibitor (mg)

Kaplan-Meier Curve

Placebo

ACE inhibitor

Surv

ival

rate

(%)

Time after start of treatment (days)

0

Preclinical Clinical

Molecular mechanism

ACE inhibition

Reduced mortality

From Molecular Mechanism to Clinical Endpoint

“Hard“ Endpoint

Asking questions


Molecular mechanism

Mode of action

Animal models

Effect in patients

Therapeutic benefit

ACE inhibition

Reduced mortality


“Hard“ Endpoint

Providing answers


Molecular mechanism

Mode of action

Animal models

Effect in patients

Therapeutic benefit

ACE inhibition

Reduced mortality


“Hard“ Endpoint

Providing answers

ClinicalPOC

PreclinicalPOC


Molecular mechanism

Mode of action

Animal models

Effect in patients

Therapeutic benefit

ACE inhibition

MI size reduction

MI size reduction

Improvedfunction

Reduced mortality

Ang II BK


“Hard“ Endpoint

Providing answers

AngII, angiotensin II; BK, bradykinin; MI, myocardial infarction

ClinicalPOC

PreclinicalPOC

Ramipril Lowers Mortality in Patients with Myocardial Infarction

Cum

ulat

ive

Mor

talit

y(%

)

Ramipril

Placebo

Time after start of treatment (months)

AIRE = Acute Infarction Ramipril Efficacy Study

From: The AIRE Study Investigators., Lancet 342, 821 – 828 (1993)

The Beneficial Effects of Ramipril Persist over Several Years

From: Hall, A., ESC Congress 2003, Vienna

Mor

talit

y(1

= 1

00%

)

Ramipril

Time after start of treatment (years)

(Placebo)

AIREX = Acute Infarction Ramipril Efficacy Extension Study

End AIREΔ = 1.45 years

Medical backgroundEpidemiology and pathophysiology of obesity

Regulation of energy balanceCentral control of appetite

Therapeutic optionsHuman recombinant leptin

Proof of Concept in Obesity

Obesity: Medical Background

Diagnosis: BMI = Body Mass Index (weight in kg divided by height in m 2); BMI > 25: overweight, BMI > 30: obesity

Mokdad, A. H. et al., JAMA 2003;289:76-79

Prevalence of Obesity and Diagnosed Diabetes Among US Adults, 1991/2001

1991

1991

2001

2001

<4% 4- 6% 7- 8% 9 - 10% > 10%No Data

<10% 10-14% 15-19% 20-24% > 25%No Data

Obesity

Diabetes

Pathophysiology of Obesity

Environ-ment

Genes

Energy expenditure

Energy intake

Energy storage

Cave painting, mesolithic period

(approx. 8000-5000 BC)

Energy Balance and Evolution

Vallorta valley, Spain

Cave painting,mesolithic period

(modified)


Vallorta valley, Spain


“Feast and Famine”

“Thrifty Genes”


• Rapid uptake and deposition of energy reserves during periods of plentiful supply • Efficient storage and conservation of energy during periods of limited supply• Hormonal und neural coordination of adaptation to supply situation• Complex and redundant regulatory systems, certain components essential

“Feast and Famine” “Thrifty Genes”

Obesity: Genes and EnvironmentD

istr

ibut

ion

(%)

Normal genetic background

Body mass index

Normal energy intake

Normal weight Obesity

High energy intake & low

energy expenditure


istr

ibut

ion

(%)


Body mass index


High energy intake



istr

ibut

ion

(%)

Genetic predisposition


Body mass index



High energy intake & low

energy expenditure


istr

ibut

ion

(%)

Genetic predisposition


Body mass index


High energy intake



isri

butio

n(%

)

Body mass index



Single gene mutation

Genetically Obese (ob/ob) Mouse

Hereditary form of obesity due to the

lack of a circulating factor (parabiosis experiments, D. L. Coleman, 1969).

In 1994 ob/ob protein (= leptin)

identified *)

*) Ref.:Zhang, Y. et al., Nature 372, 425-432 (1994)

Hypothalamus: Location

Hypothalamus

Pons

Midbrain

Hypophysis

Thirdventricle

Leptin and Energy Balance

Energy expenditure

Leptin receptors

Food intake

Adipose tissue

Appetite

Leptin

Spontaneous Mutations of Leptin or Leptin Receptors in Mice

Leptin deficiency: In ob/ob mice a Cys-to- Thr substitution at position 105 results in the synthesis of a truncated protein, incapable of being secreted

Leptin receptor dysfunction: In db/db mice a premature stop codon results in the synthesis of the short Ob-Ra with an incomplete intracellular domain

Effect of Chronic Leptin Administration (0.1 mg/kg/d) on Food Intake and Body

Weight in ob/ob and db/db Mice

Redrawn from: Levin, N. et al., PNAS USA 93, 1726-1730 (1996)

0

2

4

6

8

10

0 2 4 6 8 10 12

Day

Food

Inta

ke (g

/mou

se/d

)

20

25

30

35

40

45

50

0 2 4 6 8 10 12

Day

Bod

y W

eigh

t (g)

ob/ob: vehicleob/ob: leptin

db/db: vehicledb/db: leptin

POC with Leptin in Obesity

• Leptin as substitution therapy

• Leptin for weight loss

• Leptin after weight loss

Spontaneous Mutations of Leptin or Leptin Receptors in Humans

Leptin deficiency: C. T. Montague et al., Nature 387, 903 (1997)

A. Strobel et al., Nature Genetics 18, 213 (1998)

Leptin receptor K. Clément et al.,dysfunction: Nature 392, 398 (1998)

Congenital Leptin Deficiency

From: Marx, J., Science 299, 846-849 (2003)

Severely obese child with congenital leptin deficiency before start

of treatment with rh leptin

Age: 3.5 years

Chronic Treatment with rh Leptin in a Child with Congenital Leptin Deficiency

From: Marx, J., Science 299, 846-849 (2003)

Age: 3.5 years Age: 9 years

+ Leptin

Leptin Deficiency & Energy Balance

Energy expenditure

Leptin receptors

Food intake

Adipose tissue

Appetite

Leptin

Mean (SD) Weight Loss and Serum Leptin Levels in Obese Subjects after 24 Weeks of

Treatment with Recombinant Human Leptin

Leptin dose(mg/kg/d)

Number ofsubjects

Weightchange (kg)

Serum leptin(ng/ml)

Placebo 12 - 1.3 (4.9) 25 (40)

0.01 6 - 0.7 (5.4) 28 (20)

0.03 8 - 1.4 (4.1) 116 (100)

0.10 13 - 2.4 (5.5) 272 (322)

0.30 8 - 7.1 (8.5) 480 (522)

From: Heymsfield, S.B. et al., JAMA 282, 1568-1575 (1999)

Correlation between serum leptin levels and body fat mass (given as percent body weight) in 136 lean and 139 obese subjects. The insert shows the same correlation in a semi-logarithmic plot.

Serum Leptin Concentrations in Lean and Obese Subjects

From: Considine, R.V. et al., NEJM 334, 292-295 (1996)

Leptin Resistance & Energy Balance

Energy expenditure

Food intake

Adipose tissue

Appetite

Leptin

Leptin resistanceLeptin receptors

Mesolithic cave painting,Vallorta valley, Spain

Pieter Breughel d. Ä. (1567), Alte Pinakothek, München

Energy Balance and Evolution“Feast and Famine” “The Land of Plenty”

Leptin Signaling Pathways

Modified from: Bjoerbaek, C. et al., JBC 275, 40649-40657 (2000)

Extracellular

Intracellular

Leptin resistance?

ObRb ReceptorLeptin

Actual body weight

Target body weight

Negative energy balance(Diet, Drugs)

Changes in Body Weight during and after a Period of Negative Energy Balance

Adapted from: B. Guy-Grand, Ann. N.Y. Acad. Sci. 499, 313 (1987)

Actual body weight

Target body weight




Actual body weight

Target body weight

Persistent weight reduction


Relapse

Rebound



Actual body weight

Target body weight

Persistent weight reduction

Counterregulation


Relapse

Rebound



Reduced Leptin after Weight Loss

Energy expenditure

Food intake

Adipose tissue

Appetite

Leptin

Risk of Relapse

Leptin receptors

Adaptation of Energy Expenditure to Changes in Body Weight

Cha

nge

in e

nerg

yex

pend

iture

(kca

l/day

)

10% 20% weight reduction

10% Gewichts-zunahme

Modified after: Leibel, R.L. et al., NEJM 332, 621-628 (1995)

Return to initial weight

Study protocol (n=10)

Low-Dose Leptin in the Maintenance of Reduced Weight

From: Rosenbaum, M. et al., JCI 115, 3579-3586 (2005)

Leptin levels

Leptin treatment

0.02-0.12 mg/kg over 5 weeks


Compensatory changes after weight loss, e.g.

reduction in total energy expenditurereduction in thyroid hormone levelsreduction in sympathetic nervous system tone

were partially or fully reversed by leptin treatment




Leptin treatment ( )after a weight loss of 12kg induced a slight but significant further reduction in body weight (-3kg) and body fat mass (-3kg)

Leptin Treatment after Weight Loss

Energy expenditure

Food intake

Adipose tissue

Appetite

Leptin

Weight loss enhanced

=

= =

=

Leptin receptors

POC with Leptin in Obesity

• Leptin is an effective substitution therapy for the rare cases with genetic leptin deficiency

• Leptin does not induce sufficient weight loss in patients with common forms of obesity

• Leptin may be useful as an adjunct treatment after weight loss

Prof. Karl G. Hofbauer

Chair for Applied Pharmacology

Biozentrum / PharmazentrumUniversity of Basel

Zürich, 25.09.2007

Proof of Concept

Documents

Proof of Concept - szucs.ch · Prof. Karl G. Hofbauer. Chair for Applied Pharmacology. Biozentrum / Pharmazentrum. University of Basel. Zürich, 25.09.2007. Proof of Concept