PRECLINICAL DRUG RESEARCH
CONTENT TABLE
Pharmaceutical industry............................................................................................................... 3
Drug discovery process ................................................................................................................ 8
Therapeutic modalities .................................................................................................................... 8
General principles of drugs .............................................................................................................10
Choosing the project ......................................................................................................................15
Choosing the (right) target ...............................................................................................................16
Drug screening technologies ...........................................................................................................24
Pharmacokinetics in drug discovery ............................................................................................. 31
Pharmacology in drug discovery ................................................................................................... 52
Patent issues in drug discovery .................................................................................................... 57
Management of drug discovery .................................................................................................... 58
Drug development ....................................................................................................................... 60
Introduction ...................................................................................................................................60
Assessing drug safety: preclinical or non-clinical safety assessment.................................................64
General toxicity .......................................................................................................................... 71
Single-dose (acute) toxicity .................................................................................................... 71
Repeated-dose toxicity .......................................................................................................... 72
Safety pharmacology ................................................................................................................. 78
Genotoxicity! ............................................................................................................................. 82
General overview ................................................................................................................... 84
Regulatory tests ..................................................................................................................... 85
Additional tests ..................................................................................................................... 89
Screening tests ...................................................................................................................... 90
Reproduction toxicity ................................................................................................................. 91
Carcinogenicity .......................................................................................................................... 98
Local tolerance ........................................................................................................................ 101
Irritation/corrosion testing.................................................................................................... 102
Skin sensitization testing ...................................................................................................... 104
Phototoxicity testing ............................................................................................................ 105
Immunotoxicity testing ............................................................................................................. 105
Pediatric drug development ....................................................................................................... 107
Pharmaceutical development .................................................................................................... 116
Example drug insert: Norvir® ...................................................................................................... 124
1
,Example drug insert: Omeprazole .............................................................................................. 129
Biopharmaceuticals – biologicals ............................................................................................... 131
Introduction ................................................................................................................................. 131
Definition ..................................................................................................................................... 132
Differences .................................................................................................................................. 136
Manufacturing ......................................................................................................................... 137
Pharmacokinetics .................................................................................................................... 141
Regulatory ............................................................................................................................... 143
Immunogenicity ....................................................................................................................... 145
Delivery ................................................................................................................................... 146
Some examples............................................................................................................................ 148
Vaccines ................................................................................................................................. 148
Antibodies ............................................................................................................................... 151
Guest lecture: the global aspects of today driving the healthcare of tomorrow ............................. 167
2
,PHARMACEUTICAL INDUSTRY
• Written examination
o All subjects presented during the courses and seminars
o Major focus on the scientific insert of a marketed drug
o 3 open questions (50%) & discussing a drug insert (50%)
§ 1 question from Van Cruchten + insert + 2 from Delputte
• Introduction
o Chemicals = small molecules (SME = small molecular entities)
§ Aspirin, gluoxetine, omeprazole (against reflux), …
o Natural products = complex molecules
§ Artemether, paclitaxel, vinblastine, taxin, …
o Biologicals = large (complex) molecules
§ Insulin, interferon, EPO, …
• R & D spending
o Producing biologicals is very expensive (so treatment often too)
o We experience increased R & D expenditure (more costs in new drug
research) but les FDA approvals
§ EMA (European Medicine Agency)
§ FDA and EMA work together but can differ in approval
• Major disease areas
o You need to have a market for the drug you’re developing
o Can either be very specific one and you can ask a lot of money or you need
a big market
• Shift from preclinical to non-clinical
o First some studies you need to complete
o Normally first phase 1: assess pharmacokinetics of the drug in young
male volunteers
§ Spermatogenesis is renewed every 2 months
§ If something goes wrong, after 2 months there is normal sperm cell
production again
§ If it affects certain targets like Sertoli cells, then it can cause
permanent infertility
§ Not in women because they have a pool of cells and if they’re
affected, the woman is immediately infertile for the rest of life, also
risk of deformations of fetus à so 2 risks
§ Only on women if it’s a drug specifically for this target group, e.g.
for female reproduction à but then more studies first
o Phase 2: efficacy of the drug in small population
3
, o You don’t do everything preclinically first and then everything clinically à
it’s alternating, so each time a preclinical phase, then clinical and then
again this
o Money:
§ 20% to preclinical
§ 60% to clinical (a lot more expensive) à
§ Fail fast = fail cheap
> The worst scenario is that your drug is cancelled after
marketing because you spend all the costs but you don’t
have any revenue
> The more steps you go through, the more money you have
already put in
> So important to assess after every step!
• Regions
o Focus on Chine now, because it’s a huge population so a big market
o Also focus on Brazil because its economic situation became better
o Focus on other regions and/or age-related diseases
• Development costs and revenue cycle
o It’s difficult to bring a drug on the market without spending 2 billion dollars
on it à you need a population to be treated to get revenue
o You have about 10-15 years to make revenue because then it expires
o Between drug discovery and drug development you need to patent it to
make sure no one steals it à timing is important because it’s only valid for
a certain period of time, and it starts whenever you patent it
§ Not too early or the patent expires fast after releasing it on the
market
§ Not too late or another company might steal your drug
o So there is no investment in neglected diseases and orphan disease
§ Orphan disease = disease that occurs in small population
§ Foundations or non-profit organizations invest in drug
development for orphan diseases (big companies don’t do that
because there’s no revenue to be made if there are little patients)
• Blockbuster drugs
o Drugs that give a revenue of 1 billion dollars or more per year
o Pharmaceutical industry is very volatile, for example
§ Company of Ozempic is making lots of revenue
§ There’s another company making a drug with a better profile and
oral instead of injection
§ Stake holders are selling stock of Ozempic and buying the one of
the other company
4
, § Company of Ozempic is already laying off so many people because
of what might happen, even though they are still making profit at
the moment
• Timelines of drug development
o Drug development: takes about 10 years or longer
o Covid vaccines very fast: big investments to make it faster and regulators
were forced to look at it faster, …
o Once drug is on the market it’s not done à you need to monitor drugs
while on the market = pharmacovigilance
§ You can still detect adverse effects in very little people
§ You might not have seen it in a clinical study if it’s very rare
o Liver toxicity: lots of investment in early detection of this
§ Patient might need liver transplant: not easy to find
§ If liver transplant isn’t available or it fails à patient dies
• Competition in pharmaceutical market
o It’s very difficult to make a drug that no one else has
o Shrinking period of market exclusivity
o Increased competition between pharmaceutical companies
• Challenges for pharmaceutical sales
o Generic competition
o Price containment
§ Government tries to set low price (good for patient, not for
company)
o Poor product differentiation
§ Maybe there’s a competitor that is already further down the
process with a similar drug à they kill the compound early on so
there is no more costs that might go to waste
o Increased competition from “me-too” drugs
o Parallel importation
o Counterfeiting drugs
§ Companies that producing a similar drug and breaching the patent
5
,• Product positioning
o Generics
§ You need high volumes for high profit
§ Also highly competitive because any company can produce it
o Targeted therapeutics
§ Low sales because not many patients
§ Drug needs to be expensive to make money
§ Differentiation high: needs to be very specific
o Mega blockbusters
§ They are in the middle in most cases
§ Certain value but not very expensive drug
§ Reasonably high volume
• Failure rates un drug development
o Very high, only a few get approved
o Majority of compounds fail in preclinical development
§ Better here than later: fail fast = fail cheap
o Still 14% of drugs fail in phase III which is bad because lots of expenditure
and no revenue
o Reason why lots of drugs are failing
§ Pharmacokinetics (39%): ADME
> Absorption, distribution, metabolism, excretion
> If drug is not absorbed it won’t get into plasma and there will
be no efficacy of drug à animals are not always the best to
predict this in humans
6
, § Lack of efficacy (30%)
§ Adverse effects in man (10%)
§ Animal toxicology (11%)
§ Commercial reasons (5%)
> Market change (10 years of development), too late, …
§ Other reasons (5%)
• Major therapeutic areas
o Based on therapeutic area, e.g. Alzheimer’s, arthritis, cancer, …
o Based on pharmacological targets, e.g. G-protein coupled receptors,
enzymes, transporters, …
• Biotechnology-derived medicines
o Mainly antibodies and vaccines
o Larger proportion of “first-in-class” therapeutics
• Major pharmaceutical companies
o Roche, Novartis, Johnson & Johnson, …
o Pfizer: just manufacturing, no R&D
o They all have diverse portfolio, not just 1 focus à in case 1 goes wrong
they still have revenue
7
,DRUG DISCOVERY PROCESS
THERAPEUTIC MODALITIES
• Types of therapeutics
o Conventional therapeutics = all types of intervention aimed at alleviating
the effects of disease
§ Improve disease symptoms and/or prognosis
§ Alleviate effects of existing disease
§ Directed towards disease prevention
§ Achieve permanent cure
o Non-conventional therapeutics
§ Nutraceuticals = range of dietary preparations
> Slimming diets, diets with minerals, vitamins, fiber,
antioxidants, …
> Some scientific rationale
> Not subjected to formal regulatory approval
§ Cosmeceuticals = cosmetics supplemented with some active (?)
substances
> Reduce skin wrinkles, promote hair growth, …
> Little or no scientific rationale
> Free sales (but major market!)
• Current therapeutics
o 1: Conventional therapeutic drugs
§ Small molecule synthetic compounds
> Most of current drugs (Pharmacopoeia)
§ Natural products (or semi-synthetically derived)
> Antibiotics, anticancer, opiates, statins, …
8
, o 2: Biopharmaceuticals: therapeutic protein or nucleic acid preparations
made by techniques involving DNA technology
§ Peptide/protein mediators (insulin, GH, EPO, …)
§ Blood clotting factors
§ Enzymes
§ Antibodies (antisera, antitoxins, mAb)
§ Vaccines (inactivated, attenuated, subunit)
§ Cells / tissues (stem cells, graft- and transplant surgery)
• Beyond current biopharmaceuticals…
o 1: Gene therapy: correcting genetic defects by altering genetic material of
cells by recombinant DNA technology
§ Introduce new genes to replace missing or dysfunctional ones
(virus vector: non-integrated vs. integrated DNA)
§ Aim at single-gene disorders (cystic fibrosis, haemophilia) and
cancer
§ Restricted to somatic cell treatments
(ban on germ-cell gene therapy experiments)
§ à Not many gene therapy products licensed yet for clinical use
§ à Disappointing prospects (long-term safety, gene-delivery
systems, …)
§ Antisense-DNA
> Oligonucleotide sequence complementary to part of a
known mRNA sequence à selective blocking of expression
> But:
- Quick degradation in plasma
- Do not enter cells readily à liposomal packing
§ Ribozymes
> Specific RNA-sequences that inactivate genes by catalyzing
DNA cleavage
9
, o 2: Cell-based therapy: cell replacement therapies in various kinds of
degenerative diseases
§ Established clinical use:
> Autologous cell grafts: leukaemia, bone-marrow
malignancies
> Autologous chrondrocytes: cartilage repair
> Autologous keratinocytes: treating burns
§ Experimental exploration (but ethical issues à use of embryonic
tissues)
> Neuronal cells in brain: Parkinson’s disease, ALS,
Huntington’s disease
> Insulin-secreting cells: diabetes
> Cardiac muscle cells: restoration after myocardial
infarction
o 3: Organ- and tissue transplantation
o 4: Bionic devices
GENERAL PRINCIPLES OF DRUGS
• Phases in drug discovery and development
o Not in chronological order (seems like that in the figure)
o Lead = you’ve selected 1 or 2 most promising compounds
• Sequential drug R&D flow chart
o 1: Therapeutic concept à molecule
o 2: Molecule à registered product
o 3: Registered product à market & sales
o SO the challenge = functional integration of the 3 core disciplines
10
CONTENT TABLE
Pharmaceutical industry............................................................................................................... 3
Drug discovery process ................................................................................................................ 8
Therapeutic modalities .................................................................................................................... 8
General principles of drugs .............................................................................................................10
Choosing the project ......................................................................................................................15
Choosing the (right) target ...............................................................................................................16
Drug screening technologies ...........................................................................................................24
Pharmacokinetics in drug discovery ............................................................................................. 31
Pharmacology in drug discovery ................................................................................................... 52
Patent issues in drug discovery .................................................................................................... 57
Management of drug discovery .................................................................................................... 58
Drug development ....................................................................................................................... 60
Introduction ...................................................................................................................................60
Assessing drug safety: preclinical or non-clinical safety assessment.................................................64
General toxicity .......................................................................................................................... 71
Single-dose (acute) toxicity .................................................................................................... 71
Repeated-dose toxicity .......................................................................................................... 72
Safety pharmacology ................................................................................................................. 78
Genotoxicity! ............................................................................................................................. 82
General overview ................................................................................................................... 84
Regulatory tests ..................................................................................................................... 85
Additional tests ..................................................................................................................... 89
Screening tests ...................................................................................................................... 90
Reproduction toxicity ................................................................................................................. 91
Carcinogenicity .......................................................................................................................... 98
Local tolerance ........................................................................................................................ 101
Irritation/corrosion testing.................................................................................................... 102
Skin sensitization testing ...................................................................................................... 104
Phototoxicity testing ............................................................................................................ 105
Immunotoxicity testing ............................................................................................................. 105
Pediatric drug development ....................................................................................................... 107
Pharmaceutical development .................................................................................................... 116
Example drug insert: Norvir® ...................................................................................................... 124
1
,Example drug insert: Omeprazole .............................................................................................. 129
Biopharmaceuticals – biologicals ............................................................................................... 131
Introduction ................................................................................................................................. 131
Definition ..................................................................................................................................... 132
Differences .................................................................................................................................. 136
Manufacturing ......................................................................................................................... 137
Pharmacokinetics .................................................................................................................... 141
Regulatory ............................................................................................................................... 143
Immunogenicity ....................................................................................................................... 145
Delivery ................................................................................................................................... 146
Some examples............................................................................................................................ 148
Vaccines ................................................................................................................................. 148
Antibodies ............................................................................................................................... 151
Guest lecture: the global aspects of today driving the healthcare of tomorrow ............................. 167
2
,PHARMACEUTICAL INDUSTRY
• Written examination
o All subjects presented during the courses and seminars
o Major focus on the scientific insert of a marketed drug
o 3 open questions (50%) & discussing a drug insert (50%)
§ 1 question from Van Cruchten + insert + 2 from Delputte
• Introduction
o Chemicals = small molecules (SME = small molecular entities)
§ Aspirin, gluoxetine, omeprazole (against reflux), …
o Natural products = complex molecules
§ Artemether, paclitaxel, vinblastine, taxin, …
o Biologicals = large (complex) molecules
§ Insulin, interferon, EPO, …
• R & D spending
o Producing biologicals is very expensive (so treatment often too)
o We experience increased R & D expenditure (more costs in new drug
research) but les FDA approvals
§ EMA (European Medicine Agency)
§ FDA and EMA work together but can differ in approval
• Major disease areas
o You need to have a market for the drug you’re developing
o Can either be very specific one and you can ask a lot of money or you need
a big market
• Shift from preclinical to non-clinical
o First some studies you need to complete
o Normally first phase 1: assess pharmacokinetics of the drug in young
male volunteers
§ Spermatogenesis is renewed every 2 months
§ If something goes wrong, after 2 months there is normal sperm cell
production again
§ If it affects certain targets like Sertoli cells, then it can cause
permanent infertility
§ Not in women because they have a pool of cells and if they’re
affected, the woman is immediately infertile for the rest of life, also
risk of deformations of fetus à so 2 risks
§ Only on women if it’s a drug specifically for this target group, e.g.
for female reproduction à but then more studies first
o Phase 2: efficacy of the drug in small population
3
, o You don’t do everything preclinically first and then everything clinically à
it’s alternating, so each time a preclinical phase, then clinical and then
again this
o Money:
§ 20% to preclinical
§ 60% to clinical (a lot more expensive) à
§ Fail fast = fail cheap
> The worst scenario is that your drug is cancelled after
marketing because you spend all the costs but you don’t
have any revenue
> The more steps you go through, the more money you have
already put in
> So important to assess after every step!
• Regions
o Focus on Chine now, because it’s a huge population so a big market
o Also focus on Brazil because its economic situation became better
o Focus on other regions and/or age-related diseases
• Development costs and revenue cycle
o It’s difficult to bring a drug on the market without spending 2 billion dollars
on it à you need a population to be treated to get revenue
o You have about 10-15 years to make revenue because then it expires
o Between drug discovery and drug development you need to patent it to
make sure no one steals it à timing is important because it’s only valid for
a certain period of time, and it starts whenever you patent it
§ Not too early or the patent expires fast after releasing it on the
market
§ Not too late or another company might steal your drug
o So there is no investment in neglected diseases and orphan disease
§ Orphan disease = disease that occurs in small population
§ Foundations or non-profit organizations invest in drug
development for orphan diseases (big companies don’t do that
because there’s no revenue to be made if there are little patients)
• Blockbuster drugs
o Drugs that give a revenue of 1 billion dollars or more per year
o Pharmaceutical industry is very volatile, for example
§ Company of Ozempic is making lots of revenue
§ There’s another company making a drug with a better profile and
oral instead of injection
§ Stake holders are selling stock of Ozempic and buying the one of
the other company
4
, § Company of Ozempic is already laying off so many people because
of what might happen, even though they are still making profit at
the moment
• Timelines of drug development
o Drug development: takes about 10 years or longer
o Covid vaccines very fast: big investments to make it faster and regulators
were forced to look at it faster, …
o Once drug is on the market it’s not done à you need to monitor drugs
while on the market = pharmacovigilance
§ You can still detect adverse effects in very little people
§ You might not have seen it in a clinical study if it’s very rare
o Liver toxicity: lots of investment in early detection of this
§ Patient might need liver transplant: not easy to find
§ If liver transplant isn’t available or it fails à patient dies
• Competition in pharmaceutical market
o It’s very difficult to make a drug that no one else has
o Shrinking period of market exclusivity
o Increased competition between pharmaceutical companies
• Challenges for pharmaceutical sales
o Generic competition
o Price containment
§ Government tries to set low price (good for patient, not for
company)
o Poor product differentiation
§ Maybe there’s a competitor that is already further down the
process with a similar drug à they kill the compound early on so
there is no more costs that might go to waste
o Increased competition from “me-too” drugs
o Parallel importation
o Counterfeiting drugs
§ Companies that producing a similar drug and breaching the patent
5
,• Product positioning
o Generics
§ You need high volumes for high profit
§ Also highly competitive because any company can produce it
o Targeted therapeutics
§ Low sales because not many patients
§ Drug needs to be expensive to make money
§ Differentiation high: needs to be very specific
o Mega blockbusters
§ They are in the middle in most cases
§ Certain value but not very expensive drug
§ Reasonably high volume
• Failure rates un drug development
o Very high, only a few get approved
o Majority of compounds fail in preclinical development
§ Better here than later: fail fast = fail cheap
o Still 14% of drugs fail in phase III which is bad because lots of expenditure
and no revenue
o Reason why lots of drugs are failing
§ Pharmacokinetics (39%): ADME
> Absorption, distribution, metabolism, excretion
> If drug is not absorbed it won’t get into plasma and there will
be no efficacy of drug à animals are not always the best to
predict this in humans
6
, § Lack of efficacy (30%)
§ Adverse effects in man (10%)
§ Animal toxicology (11%)
§ Commercial reasons (5%)
> Market change (10 years of development), too late, …
§ Other reasons (5%)
• Major therapeutic areas
o Based on therapeutic area, e.g. Alzheimer’s, arthritis, cancer, …
o Based on pharmacological targets, e.g. G-protein coupled receptors,
enzymes, transporters, …
• Biotechnology-derived medicines
o Mainly antibodies and vaccines
o Larger proportion of “first-in-class” therapeutics
• Major pharmaceutical companies
o Roche, Novartis, Johnson & Johnson, …
o Pfizer: just manufacturing, no R&D
o They all have diverse portfolio, not just 1 focus à in case 1 goes wrong
they still have revenue
7
,DRUG DISCOVERY PROCESS
THERAPEUTIC MODALITIES
• Types of therapeutics
o Conventional therapeutics = all types of intervention aimed at alleviating
the effects of disease
§ Improve disease symptoms and/or prognosis
§ Alleviate effects of existing disease
§ Directed towards disease prevention
§ Achieve permanent cure
o Non-conventional therapeutics
§ Nutraceuticals = range of dietary preparations
> Slimming diets, diets with minerals, vitamins, fiber,
antioxidants, …
> Some scientific rationale
> Not subjected to formal regulatory approval
§ Cosmeceuticals = cosmetics supplemented with some active (?)
substances
> Reduce skin wrinkles, promote hair growth, …
> Little or no scientific rationale
> Free sales (but major market!)
• Current therapeutics
o 1: Conventional therapeutic drugs
§ Small molecule synthetic compounds
> Most of current drugs (Pharmacopoeia)
§ Natural products (or semi-synthetically derived)
> Antibiotics, anticancer, opiates, statins, …
8
, o 2: Biopharmaceuticals: therapeutic protein or nucleic acid preparations
made by techniques involving DNA technology
§ Peptide/protein mediators (insulin, GH, EPO, …)
§ Blood clotting factors
§ Enzymes
§ Antibodies (antisera, antitoxins, mAb)
§ Vaccines (inactivated, attenuated, subunit)
§ Cells / tissues (stem cells, graft- and transplant surgery)
• Beyond current biopharmaceuticals…
o 1: Gene therapy: correcting genetic defects by altering genetic material of
cells by recombinant DNA technology
§ Introduce new genes to replace missing or dysfunctional ones
(virus vector: non-integrated vs. integrated DNA)
§ Aim at single-gene disorders (cystic fibrosis, haemophilia) and
cancer
§ Restricted to somatic cell treatments
(ban on germ-cell gene therapy experiments)
§ à Not many gene therapy products licensed yet for clinical use
§ à Disappointing prospects (long-term safety, gene-delivery
systems, …)
§ Antisense-DNA
> Oligonucleotide sequence complementary to part of a
known mRNA sequence à selective blocking of expression
> But:
- Quick degradation in plasma
- Do not enter cells readily à liposomal packing
§ Ribozymes
> Specific RNA-sequences that inactivate genes by catalyzing
DNA cleavage
9
, o 2: Cell-based therapy: cell replacement therapies in various kinds of
degenerative diseases
§ Established clinical use:
> Autologous cell grafts: leukaemia, bone-marrow
malignancies
> Autologous chrondrocytes: cartilage repair
> Autologous keratinocytes: treating burns
§ Experimental exploration (but ethical issues à use of embryonic
tissues)
> Neuronal cells in brain: Parkinson’s disease, ALS,
Huntington’s disease
> Insulin-secreting cells: diabetes
> Cardiac muscle cells: restoration after myocardial
infarction
o 3: Organ- and tissue transplantation
o 4: Bionic devices
GENERAL PRINCIPLES OF DRUGS
• Phases in drug discovery and development
o Not in chronological order (seems like that in the figure)
o Lead = you’ve selected 1 or 2 most promising compounds
• Sequential drug R&D flow chart
o 1: Therapeutic concept à molecule
o 2: Molecule à registered product
o 3: Registered product à market & sales
o SO the challenge = functional integration of the 3 core disciplines
10
