PHAR - Drug Design and Development

Overcoming challenges of drug attrition

reduce attrition - better predictive models (especially for safety issues) - better animal models (linking mechanism to disease) - experimental medicine (innovative ways of demonstrating efficacy in humans) changing business model -reducing internal investment in discovery research - turn to biotech and academia - increase of outsorcing to CROs (contract research organisations) - R and D becomes Search and Development - collarborative or 'precompetitive' approaches - refocusing research portfolio and asset swapping

Ethics of toxicology

replace refine reduce

Advantages and disadvantages of using healthy volunteers in phase 1 studies

scientific advantages - physiological processes are well understood - less physiological variation or confounders (no illness, organ dysfunction, interfering drugs) - responses are more uniform practical advantages - accessible - eligible for future studies - low drop out rate - easier to obtain blood for PK profile disadvantages - actual patients: older, sicker, more comorbidities (renal/hepatic function), contaminant drugs - target of the drug may not be present in healthy subjects

history of human experiments

- 1840s Sims performes surgical experiments on enslaved African women - Tuskegee Syphilis Study - The Monster Study - Nazi human experiments (high altitude experiments, antibiotics, Josef Mengele twins, others [poisons, TB, toxic gas, limb transplant, sterilisation, malaria]) - Nuremberg 1946-1947 doctors trial

Repeat-dose toxicity

- 2 mammalian species (rodent and non-rodent) - except for biologicals - one dose -> produce dose-limiting toxicity - one dose -> should be non-toxic - aim to mimic planned clinical design where possible - often 28 day or 90 days long parameters to observe: - clinical observations - functional parameters (ECG, ophtalmoscopy, respiration, renal output) - clinical pathology (haematology, clinical biochemistry, urinalysis) - gross pathology and organ weights - histopathology

ABC transporter protein family

- 48 members, 7 subfamilies - Major superfamilies: P-gp/ABCB1 (P-glycoprotein), MRP2/ABCB2 (multidrug resistance-associated protein 2), BCRP/ABCG2 (breast cancer resistance protein)

Objectives of Clinical Trials

- Evaluate new preventative and therapeutic measures and modes of health care delivery - observational: the investigators OBSERVE the population to make an interference on the relationship between variables - experimental: the investigators INTERVENE in the natural history altering ONE OF THE VARIABLES and then making an interference of the relationship between the variable and the outcomes Interventions: - new treatments for diseases - new methods for primary prevention - screening programs - new ways of organising or delivering health services

Paul Ehrlich

- Father or modern drug discovery - earliest chemotherapy - hypothesis: molecules can bind to specific receptors - systematic synthesis and testing of arsenicals - used observation to design and change his molecules - new technology available -> structure determination 1908 Nobel Prize: Antimicrobial discovery - arsphenamine "606", Salversan - first effective treatment for syphilis

When to use healthy volunteers or patients in Phase 1 study

- HV -> phase 1 studies if the IMP is a small molecule/antibody with an expected low-risk profile patients -> trials of cancer treatments (in this case they may benefit). often have advanced cancer and have received all current treatments (nothing to lose really) cellular and gene-based regimes: - emerging fields with own specific consideration -> they are always trialled in patients - may exist for and extended period of time - may have a permanent effect - effects may evolve over time - may require surgery/invasive procedure to deliver to the target site - cellular products may elicit and undesired immune response - there may be a lack of other treatment options

Prof Sir James Black

- Nobel Prize for Medicine 1988 - development of propanolol, the first beta blocker used for the treatment of heart disease - exploitation of endogenous molecules - modified to find selective compounds (adrenaline to propranolol) - histamine to cimetidine (H2 antagonists for gastric ulcers) - specific to biolological systems

Facilities in clinical trial design

- P1 studies should be conducted in specialised centres -> accredited by the MHRA - safety: resuscitation capabilities, experience of personnel, monitoring of subjects, proximity to a hospital with an ICU - pharmacy capabilities: abilities to store and dispense drugs - sample acquisition/analysis: lab to process blood samples - accessibility to patients or healthy volunteers

Challenges of biologics production

- SME = chemical synthesis (medicinal chemistry) - biologics = biochemical synthesis (molecular biologist, biochemical engineering) - choosing expression systems (correct product, sufficient product yield, product isolation) - Regulatory problems (product contamination, product activity, batch variability, product stability)

Biomarker, surrogate endpoint, clinical endpoint

- a measurable indicator of some biological state or condition. often measured and evaluated to examine normal biological processes, pathogenic processes, pharmacologic responses to a therapeutic intervention - measure of effect of a specific treatment that may correlate with a real clinical endpoint, but does not necessarily have a guaranteed relationship ("biomarker intended to substitute for a cinical endpoint") - direct measure of outcome, clinical benefit, how a patient feels/functions or survives

Sources of toxicology

- all medicines contain more than the active ingredient - related substances - process residues - degradation products - excipients

Bias

- allocation/selection bias - design bias - co-intervention bias - observer bias - analysis bias - reporting/publication bias - researcher bias

Most frequent on therapy adverse events

- arthralgia - nausea - anorexia - insomnia - vomiting - pain - diarrhea - fatigue - dizziness - abdominal pain

Function of ABC transporters

- binding of the two ATPs at the dimer interface -> could induce changes in TMD conformation - leads to dimerisation and configuration of a sandwich-like NBD - substrate binds to TMD -> induce a decrease in the activation energy for NBD dimerisation - ATP hydrolysis -> separates NBD -> releases substrate into extracellular space - restores a stable conformational state of the NBD

Biopharmaceuticals vs Traditional medicines (SME)

- biologics are more specific/complex - biologics have multiple binding sites -> elicit multiple functions - side effects are associated with ON TARGET effects (SME have off target effects) - size (large/small) - stability (heat sensitive vs stable) - immunogenic/non-immunogenic - species-dependent vs species-independent - not oral active/orally active - long lasting/short acting

Development phase

- building on the lead optimisation phase - pre-clinical candidate molecules progressed - chemical development (good manifacturing route, from grams to kgs to tonnes) - pharmacy (formulation, physical form) - detailed pharmacology - acute and short-term toxicity - geno toxicity - clinical trial plans (regulatory affairs)

In vitro/In vivo toxicology/safety testing

- can provide information on MOA - can provide early indication of toxicity types of tests - protein binding assays - CYP450 induction/inhibition - cardiovascular toxicity (leading cause of toxicity-related drug attrition) -> hERG inhibition assays

Declining R and D productivity

- despite the increasing global RD expenditure, with the development time remains the same - the number of global new medicines is not increasing genomics - might provide a range of new targets - target proteins increased from 500 to 50 000 - more success if the genetic basis is known more molecules - from one chemist, one molecule -> one chemist, computer, robot and 10 000 molecules partnerships - industry + academia + prescribers + regulators + society individual patient therapy - more targets - more molecules - pharmacogenetics - disease redefinition

How to introduce drugs into clinical practice - SAFETY

- does the benefit outweigh the risk - is there something missing from the trial evidence (subgroup, time of follow up) celecoxib, a COX-2 selective nonsteroidal anti-inflammatory drug - comparator - NSAID - increased GI complications + increased cardiovascular toxicity stomach ease -> Pfizer scandal

How to introduce drugs into clinical practice - CONVENIENCE

- dosing - route of administration - taste - formulation desferasiox oral iron chelator. - very similar or even better results as its comparator (deferoxamine) - one is oral the other is IV infusion -> more convenient

Physician prescribing patterns

- drug reps/sponsored trials/advertising/bribing docs, pharmacists, nurses, allied health professionals - pharmaceutical enticements on physicians prescribing patterns - "luxurious resort on West coast"

Sample Size

- eliminate the possibility that the difference is due to the intervention and not simply due to chance - to calculate the sample size -> assumptions are made about the incidence of the primary outcome and the likely treatment effect of the intervention under-estimation: statistically non-significant over-estimation: in very large sample even small difference will be statistically significant + ethical issues of large number of people who did not get the drug. statistically - level of significance - power - clinically meaningful difference - demonstrate equivalence is highest and demonstrate equality is lowest

Characteristics of a medicine (small molecules and biologicals)

- engages the desired molecular target -achieves desired therapeutic effect - drug gets to the right site - maintains the right concentration for the right duration - A stable formulation containing the drug - safe with respect to adverse effects - safely eliminated from the body

Qualified person for pharmacovigilance

- establishing and maintaining GSK's - acting as a single contact point on a 24-hour basis - overview of safety profiles and emerging safety concerns

Preclinical drug target validation

- experimental validation of the target according to its propoesd MOA -> proof it is likely to be clinically efficacious = proof of principle - in vitro, in vivo, in silico - on-going process during which evidence is collected -> increases confidence the target has therapeutic relevance (expression in diseased cells/tissue, drug modulates this on a bioassay, disease state is ameliorated by the drug in cell or animal model) - biology is always unpredictable

Generic drugs and biosimilars

- generic: copies of a brand-name drugs that have xactly the same dosage, indended use, effects, side effects, route of administration, risk, safety and strength as the original drug = brand-name counterparts - biosimilars: biologic medical product that is almost an identical copy of an original product that is manufactured by a different company

Benefits of biopharmaceuticals

- highly specific - less off-target effects - well-tolerated - can replace/repair underlying pathology - quicker to clinic (on average 1 year) - entry to market is higher, patents longer and further in scope

First in-human studies/Phase I studies

- human research -> non-interventional/interventional studies -> first into human or intervention has been used before - does not benefit subjects or patients - also known as non-therapeutic trials - conducted with healthy volunteers or patients Parts - trial of single ascending doses (SAD) - tolerability, safety, PK and PD - multiple ascending doses (MAD) - steady state parameters - ADME studies (using radiolabelled IMP) - Bioavailability of the IMP - effect of various factors on the activity of the IMP (food, age, gender etc.) - Effect of IMP on the QT interval (or other cardivascular effects) 50-200 healthy subjects: individual who is not known to suffer any significant illness relevant to the proposed study - ordinary range of body measurements (weight) - mental state -> able to understand and give valid consent to the study

Target Selection (Identification and validation)

- identify molecular targets that are involved in disease progression - prove that manipulating the molecular target can provide therapeutic benefit for patients - cellular and genetic targets: enzymes (e.g. kinases, proteases), GPCRs, ion channels, nuclear hormone receptors, PPIs -techniques: gene mapping, separation and characterisation of proteins, data mining, computer screening, analysis of biological and molecular data - genomics, proteomics, bioinformatics

The Principle Investigator in Clinical Trial Design

- in charge of the design and conduct of the trial - responsible for subject safety - must hold a post-graduate qualification related to pharmacology - SPONSOR should ensure that PI knows enough about the agents (target, MOA, potential adverse effects) -> manage the informed consent process

Principles guiding research in humans

- informed CONSENT is essential - results must AID SOCIETY rather than individuals - research should be based on PRIOR ANIMAL WORK - physical and metal SUFFERING MUST BE AVOIDED - research in which DEATH OR DISABLING INJURY IS EXPECTED should not be conducted - The RISKS SHOULD BE JUSTIFIED by the anticipated benefits - research must be conducted in PROPER FACILITIES and by QUALIFIED SCIENTISTS - participants may FREELY END the experimentation - experiment MUST STOP if it proves too dangerous

Multidrug resistance of ABC efflux transporters

- intrinsic or acquired resistant -> chemotherapeutic failure and malignant tumour progression in anticancer pharmacotherapy - increased drug efflux via ABC transporters - overexpressed in cancer cells -> forming a unique defense against chemotherapeutics, endogeneous and exogeneous cytotoxic agents - polyspecificity: structurally diverse drugs are extruded - they reduce the concentration of endo and exotoxins ABCB1 substrates: eryhtromycin (antibiotic), hydrocortisone (corticosteroid), digoxin (cardiac glycoside), cimetidine (H2-antagonist), cyclosporin (immunosuppressant)

Structure-based design

- lead discovery strategy - X-ray and NMR derived 3D structures of proteins - homology models - active site analysis - pharmacophores - docking - ab initio design - fragment binding e.g. neuraminidase

Fragment-based discovery

- lead discovery strategy - structure guided growth of low-affinity fragments into drug molecules - low affinity fragment hit - bound to Hsp90 protein - developed potent lead - lead to the discovery of Onalespib (Phase II drug against solid tumours)

High Throughput Screening

- lead discovery strategy - screening large numbers of compounds (>1M) in assays with a simple read out (yes or no) - automatised, miniaturised assays - based on historical collections - computational structure/data visualisation, analysis and management tools) - quality of compounds - unreliable - combinatorial chemistry -> many of few - medicinal chemistry - emerging power of AI in modern collection built by design e.g. Sorafenib (Raf kinase in Renal cell carcinoma) was developed based on an HTS hit

George Hitchings and Gertrude Elion

- linked isease to aberrations in cellular processes and biochemistry - ligand-based drug discovery - design of NME with specific molecular structure - based on the structure of purine and pyrimidine - drugs for leukaemia, gout, malaria and herpes

Lead discovery - criteria for lead compounds

- measured and in-silico assessment - synthetic accessibility - potency (dose response) - specificity - selectivity - toxicology - drug-like structure - physical properties (solubility, lipophilicity) - preliminary SAR (structure activity relationship) Ideal scenario: - structure and ligand-target complex is determined (e.g. crystal structure) - activity demonstrated in vivo (animal model)

In vitro genetox - micronucleus test

- micronuclei are formed when a chromosome (or a fragment) is unable to migrate to a mitotic pole during anaphase, and is left out of the daughter nuclei - detects chromosome breaks (caused by clastogens) and aneuploidy (caused by aneugens) - test can be done on cultured mammalian lymphocytes or cell lines (CHO, V79, CHL/IU, L5178Y, TK6)

Pharmacovigilance of vaccines

- most vaccines are prophylactic - given to healthy subjects, tolerance of ADRs is low - many vaccines are mandatory in many countries - many vaccines are given to children, some at birth - number of doses distributed are very high with nearly 100% coverage for some vaccines -> nearly every event can be expected to occur by coincidence following some vaccines (even very rare events) - besides anaphylaxis -> few well-recognised events attributable to vaccination - if a severe event is related to a vaccine -> this will most likely lead to withdrawal of the vaccine

Phase 1 Clinical Trial Study Design

- multiple factors inform study design: e.g. level of risk, PK, PD, number of dose levels to investigate, number of subjects, capacity of the research facility - no regulatory need for Phase 1 to be double-blind, often single-blind is used Parallel group design - each subject receives one dose of drug or placebo - within each group some get the drug other get P - drug escalates from one group to the next - used if drug has long half-life or if multiple doses undesirable Crossover design - more efficient - within subject variability can be measured (e.g. effect of food) - ideally suited to small molecules with short half life - 'interlocking' allows for a greater wash-out period

Dose range finding (DRF) and Maximum tolerated dose (MTD)

- not normally classed as regulatory - one rodent and one non-rodent species - phase 1: single dose escalation (SDE) phase consisting of a small number of repeated administrations to determine the MTD - phase 2: repeat dose (RD) protocol (usually 3 dose levels) 7-14 days in duration - observe: clinical observaitons, clinical pathology parameters, gross pathology, TK evaluation - organ weights and histopathology -> in RD phase

Polispecificity of ABCB1

- polispecificity of the drug-binding cavity - bc of their side chains (Phe and Tyr side chains, flexible and bale to rotate + aliphatic side chains, hydrogen-bond donor side chains) structurally diverse ligands can be accomodated (Gutmannet et al. 2010) - flexibility of the surrounding helices (glycine and proline rich residues) (Wen et al., 21013) - structure of transporter ->forms a single bipartite binding site, which recognises a spectrum of substrates (Johnson and Chen, 2017)

Aims of nonclinical toxicology studies

- predict the likelihood of toxicity in humans - identify any target organs for toxicity - the reversibility of toxicity - identify a safe starting dose for Phase I clinical studies and the highest dose that can safely be administered (based on NOEL/NOAEL/HNSTD) - identify parameters/biomarkers for clinical monitoring

Importance of risk management

- regulatory expectaion - company perspective - patient perception prescribing information alone may not be sufficient -> not all prescribers/patients read all of the information examples: - tracleer (bosentan) for pulmonary hypertension - leponex (clozapine) for psychosis - accutane (isoretinoin) for acne - Thalomid (thalidomide) for leprosy and MM

Marketing authorisaiton

- results in a licence to market a pharmaceutical product in a particular country or a group of countries - defined the quality, permitted uses and restrictions of use - restricts the promotional claims which can be made - defined the packaging and labelling of the product

Blinding and placebo

- single blind -> those participating in the study are made unaware of which group they are in (in order to remove co-intervention, observer and analysis bias) - double blind -> neither those participating in or conducting the trial are aware who has been allocated to which group Requirements for placebo - to be effective -> both groups must receive something that appears to be identical (pill, infusion, sham procedure) - placebo effect

Success of first-in-class drugs

- speculative research targets - expensive, not often succeeds "fast followers" or innovative improvers often win - established efficacy of the lead compound -> further improve to overcome shortcomings e.g. atenolol or amlodipine 'me too' - structurally similar, same MOA - but a new hypothesis - creation of a patentable entity e.g. bisoprolol same target but different properties - efficacy (potency, clinical outcome) - efficiency (route of administration, dosing interval, tolerability, need for monitoring)

CTIMP approval process

- sponsor = UCL/UCLH Joint research office - Research Ethics Committee Approval (NHS 'IRAS' system) - Authorisation by the Medicines and Healthcare Regulatory Agency (MHRA) -> regulates CTIMPs in the UK - Good Manufacturing Process (GMP) - specify how IMPs will be manufactured - NHS permision (if on an NHS-site or in patients)

Safety assessment/monitoring

- spontaneously reported symptoms/signs - symptoms/signs reported as the result of a probe (e.g. survey or questionnaire) - vital signs (BP, HR, Temp) - blood tests (renal, liver function, full blood count) - special safety assessment (ECG, Neurological exam, visual, hearing) adverse event = any untoward medical occurrence in a subject to whom a medical product (MP) has been administered, including occurrences which are not necessarly caused by or related to the MP adverse reaction = 'untoward and unintended' response in a subject to an IMP which is related to any dose administered to that subject serious adverse events (SAEs) = any adverse event that results in death or immediate risk of death - hospitalisation or prolongation of existing hospitalisation - new disability - congenital abnormality or birth defect

Randomisation

- study participants are randomly allocated to different arms of the study - removes allocation/selection bias - helps ensure that the groups are similar and the only major difference is the variable being studied - generated by computers and calculators - STRATIFIED RANDOMISATION: random assignment within group defined by participant characteristic (gender, age, disease severity) to ensure a good balance of these across the groups

Recruitment and reimbursement

- subjects must be recruited of their own free will - money should NOT be viewed as and inducement - rather reimbursement for time and inconvenience = minimum hourly wage -> should never be related to risk - study-specific adverts must be approved by the REC (payment must not be over-stressed) - subjects can be in only one trial at a time (should not receive an IMP within 3-months of the last one, have to be monitored to ensure they are not taking part in too many trials)

Ideal drug target

- target is disease-modifying and/or has proven a funciton in the pathophysiology of a disease - modulation of the target is less important under physiological conditions or in other diseases - if the druggability is not obvious (e.g. as for kinases) a 3D-structure for the target protein or a close homologue should be available for druggability assessment - target has a favourable 'assayibility' enabling high throughput screening - target expression is not uniformly distributed throughout the body - a target/disease-specific biomarker exists to monitor therapeutic efficacy - favourable prediction of potential side effects according to phenotype data (e.g. in KO mice or genetic mutation databases) - target has a favourable IP situation (no competitors on target, freedom to operate)

How to introduce drugs into clinical practice - EFFICACY

- use best level of evidence available - is the comparator the gold standard treatment - what are the clinical endpoints that are being measured -> are these directly applicable in practice e.g. infliximab (anti TNF alpha) in the treatment of rheumatology

Considerations for medical research participation

- what is the purpose fo the study - why have I been chosen - Do I HAVE to take part? - What will I be asked to do if I take part - What other treatments are available? - Are there any benefits in taking part? - Are there any risks in taking part? - What if something goes wrong? Am I insured? - What if new information becomes available? - What will hapen at the end of the study? - Will my taking part be kept confidential? - Who is organising the study?

Pharmacokinetic challenges of drug optimisation

- when new hit identified that works well in vitro - low oral uptake (absorption) - limited distribution to target tissue (distribution) - rapid excretion/degradation (elimination) - severe side effects or toxicity (elimination) next phase: - physio-chemical properties (non-specific) - interaction with transporters and enzymes (specific)

Targeting TNFalpha in arthritis

1.) Carswel et al. 1975 identified in mice and its effect on fibrosarcoma in vivo master regulator in inflammatory response -> antiinflammatory cytokines, bone and cartilage destruction, pro-inflammatory cytokines 2.) Animal model = collagen-induced arthritis - Complete Freund's adjuvant -> induces immune response - pathological features associated with RA (cartilage degradation, synoval hyperplasia, immune cell infiltration) 3.) TNFalpha was shown to ameliorate and protect collagen in collagen-induced arthritis (Williams et al. 1992) 4.) Infliximab - chimeric monoclonal antibody biologic drug Human trials successful

The pharmacovigilance process

1.) Data in - literature reports - spontaneous reports - clinical trial data - regulatory reports - licensing pratners 2.) Database entry 3.) Data Review - signal evaluation 4.) Output - Licensing Partners - World-wide regulatory reports (expedited or periodic) - Risk-management plans (RMPs) - Amend prescribing information - Submission - Enquiry response

The discovery of antibiotics using animal models

1.) Fleming - London Team Identified that penicillium inhibited the growth of Staphylococus aereus 2.) Chain, Heatley and Florey - Oxford Team Characterised penicillin in mouse models, translated these studies to man and generated this drug on an industrial scale Experiment - 8 mice -> inject 5 ml and 10ml penicillin

The drug discovery continuum

1.) Target identification 2.) Target validation MS: Hit Understanding of disease and its underpinnig biology to allow the selection and prosecution of the best targets 3.) Lead discovery MS: Lead 4.) Lead optimisation MS: Candidate 5.) Development MS: IND (investigational new drug) Discovery and production of drug molecules with the right efficacy, ADME and safety profile 6.) Clinical Trials MS: new drug application 7.) Launch Clinical evaluation of candidate compounds in humans Time: 10-15 years Cost: 2BN pounds

In vitro genetox - comet assay

1.) detects a rang eof DNA damage - strand breaks (single or double) - repair induced breaks - alkali-label sites (ALS) - abasic sites - DNA cross-linking (DNA-DNA and DNA-protein) - doesn't detect aneuploidy 2.) can use any tissue from the animal - selection of tissues -> should be evaluated based on data from structural analogues, ADME studies or any other toxicological information 3.) common to measure the % DNA in tail -> proportional to DNA damage

Historical regulations of research ethics

1900 - Berlin Code of Ethics - unambiguous consent needed after thorough explanation of possible negative consequences of participation in study - excluded sue of minors or incompetent subjects - required documentation of fulfilment of code requirements in the medical records - being in a study should not interfere with standard diagnostics, care and prophylaxis - Nuremberg Code 1947 Declaration of Helsinki - first version in 1964 by WMA - 7 amendments, most recent 2013 - not legally binding, rejected by the FDA - medical research is subject to ethical standards -> promote and ensure respect for all human subjects and protect their health and rights - primary purpose of med. res is to generate new knowledge -> it can never take precedence of the rights and interests of individual research subjects

Substrates for ABC transporters

ABCB1 (analgesics, antibiotics, anticancer drugs, anthistamines, HIV protease inhibitors, immuno suppressive agents) ABCC2: antibiotics, anticancer drugs, HIV drugs ABCG2: antibiotics, antivirals, antibiotics, antihypertensives, calcium channel blockers

Non-clinical safety assessment

Aim: - to give reassurance that the new drug is safe - to protect volunteers, patients and the workforce - to fulfil regulatory requirements Studies: general toxicology, metabolism, genetic toxicology, carcinogenecity, reproductive toxicology, safety pharmacology alternative: choice is a balance between relevance to humans and specificity purified enzymes -> subcellular fractions -> isolated cells -> perfused organs -> intact animals -> human

Risk and benefit evaluation in pharmacovigilence

Bupropion - used to treat major depressive disorder and to support stopping smoking - risk: 0.1% seizure, 0.12% hypersensitivity - benefit: 30% of real-life quite rate per 10K treated patients - 22 SAEs vs 190 of smoking-related morbidity + 123 deaths avoided in 20 years Abacavir - NRTI used to prevent and treat HIV/AIDS - hypersensitivity Alosetron - maximum acceptable risk - moderate colitis, impacted bowel, severe colitis, perforated bowel

Research Ethics Committee

Declaraton of helsinki - research protocol must be submitted for consideration, comment, guidance and approval to the concerned research ethics committee before the study begins - this committee must be independent - have the right to monitor ongoing studies - at the end of the study the researchers must submit a final report Role of REC - protect volunteers - protect investigators from themselves - ensure the needs of society do not trump the individual basic human rights - encourage highest quality science REC considerations - the quality of the science and the pre-clinical data (and quality of the team) - is it in the interests of society that question be answered? - assessment of risks to the subjects - how will these risks be managed? - assessment of the informed consent process - appropriateness of the protocol and research facilities - how data will be collected, stored, analysed and disseminated appropriately

Legal background of medical research

EU clinical trials detective 2001 - legal framework -> sets out how a clinical trial must be conducted - based on Declaration of Helsinki -> in law - EU Clinical Trial Regulation 2014 will come into place when the IT infrastructure is established - EU clinical trial and database: clinical trial information in the EU, public database - Research Ethics Committees

Attrition in drug discovery

Early stage - target validity - no suitable molecules - change in commercial priorities Late stage - scientific reasons (preclinical efficacy/safety, bioavilability) - technical reasons (formulation issues, patent issues) - commercial reasons (cost of goods, budget/resource constraints, portfolio rationalisation, potential value) -regulatory reasons (regulatory hurdles/requirements/decisions) most common reasons: - clinical safety - non-clinical toxicology - rationalisation of company portfolio

Regulatory Reporting in pharmacoviligence

Expedited reporting - individual cases - serious or serious and unexpected reactions - defined timeline This applies to reports from spontaneous sources and from any type of clinical or epidemiological investigation, independent of design or purpose. Periodic reporting - groups of cases - serious and non-serious reactions - longer time period (e.g. annual) provide an evaluation of the risk-benefit balance of a medicinal product at defined time points post-authorisation

Determining starting dose

FDA approach - No observable adverse effect level (NOAEL) - derivded from animal toxicology studies - NOAEL is converted to a human equivalent dose (HED) - on the basis of body surface area - safety factor is applied to give the maximum recommended starting dose (MRSD) - MRSD is adjusted on the basis of the predicted pharmacological action EMA approach - minimal anticipated biological effect level (MABEL) Dose escalation - usually 3-5 fold with each increment - all data from previous doses are reviewed - stopping rules pre-defined (severe adverse events, effects on vital signs or blood tests) - decision maker pre-specified

Comparison Groups

Fundamental principle: at least two groups: intervention and the comparator group - IV vs no IV - IV vs placebo/sham - IV A vs IV B (other treatment) TB vaccine - vaccine vs control -> showed lower TBC deaths - physician chose more intelligent and cooperative parents -> children of non-cooperative parents were control - after randomisation -> similar results

Inflammatory diseases case study

Glucocorticoids -> anti-inflammatory and immuno-suppressive effects (vasodilation, leukocyte migration/activation, fibrosis, clonal expansion of B and T cells, production of IL-1, IL-2... TNF alpha, generation of prostaglandins) side effects: - suppression of response to injury and infection - cataracts - increased abdominal fat - skin thinning - osteoporosis - increased appetite - hyperglycemia - moon face - buffalo hump - peptic ulceration - cs-induced glaucoma Mono/poly nuclear phagocytes (chemotaxis, diapedesis, adhesion) T cells (lysis, apoptosis up, proliferation, cytotoxicity down) B cells (plasma cell formation, antibody production, lowered antigen presentation)

Target identificaion

Historically - traditional medical uses of natural products e.g. foxglove, poppy - experimentation - understanding of physiology and pathology e.g. angina pectoris - elaboration of the structure and function of endogenous chemical mediators and receptors e.g. betablockers or insulin Modern methods - reverse (gene to phenotype) - forward (phenotype to gene) Strategies - gene expression profiling - focused proteomics - pathway analysis - pathway databases - phenotype analysis - phenomic database - functional screening (siRNAs, shRNAs) - genetic association - literature DISEASE UNDERSTANDING + UNDERSTANDING OF BASIC MOLECULAR MECHANISM + ACCESS TO MODELS AND TECHNOLOGIES

Hatch-Waxman Act of 1984

INNOVATION + AFFORDABILITY - after patent expiry - generic drugs no longer -need to prove their safety and efficacy - no clinical trial, but an ANDA (abbreviated new drug application) - first generic gets 180 day exclusivity - provide brand manufacturers with incentives to develop new pharmaceuticals through a 5-year exclusivity period - 3 year exclusivity for improved versions of brand pharmaceuticals effect: - 19% of prescriptions were generic now nearly 90% - 35% of pharmaceuticals had generic competitor, now 80% - generics entered market 3-5 years after patent expiry, now immediately (can capture 90% market share)

Lead discovery

Identification of Hits (potential chemical starting points) via primary assays 1.) ligand-based: exploiting molecules known to bind to the target 2.) structure-based: exploiting knowledge of a 3D structure of the target protein or its protein ligands 3.) HTS: screening large sets of diverse molecules 4.) Natural compounds: with known clinical/therapeutic effects

Labelling and intervention sbeyond labeling

Information - indications, important limitations, contraindications, warning and precautions, adverse reactions, pregnancy communication strategies (publicaitons, letters, medical and non-medical advertising) education and outreach programmes (e.g. reaction warning cards) systems guiding prescribing, dispensing and use restricted access/distribution control

Targeting ABC efflux transporters to overcome MDR

Inhibitors - first generation led to toxic side-effects - cyclosporine A with doxorubicin - second-generation increase inhibitory effects and lower toxicity - third generation: higher affinity to ABC transporters (zosuquidar,tariquidar) - haven't reached clinical trials tyrosine kinase inhibitors - EGFR inhibitor (icotinib, gefitinib, erlotinib, lapatinib) - VEGFR inhibitor (telatinib, sunitinib, motesanib, vandetanib) - PDGF (masitinib) - nilotinib (inhhibits P-gp, and p38 MAPK) Natural origin - chinese herbal medicines (flavonoids, coumarins, terpenoids, alkaloids) - honokiol - calebin-A (Curcuma lunga) RNAi or siRNA epigenetic regulators

chronic toxicity/carcinogenecity safety test

Intended route of exposure in humans chronic toxicity - 2 species (rodent for 6 months, non-rodent for 9 months) - parameters (clinical observations, clinical pathology, gross pathology and organ weights, histopathology) carcinogenecity - 2 years in rats - usually 18 months in mice - number of survivors in control shouldn't fall below 25% -parameters (clinical observations, gross pathology/histopathology)

ABCG2 and oral availability (Multidrug resistance)

Intestine and liver - increases direct intestinal excretion (reduces net uptake from the gut lumen) and liver-mediated excretion - direct intestinal/hepatobiliary excretion - decreases oral availability blood-tissue barriers -increases excretion into the blood - decreases tissue penetration (brain, lymphocyte, stem cell) - physiological role is to limit exposure to ingested toxic xenobiotics

Ways of drug delivery

Local: - eyes/nose (drops or sprays) - skin (creams or ointments) - lung (inhalers) - rectum (creams or suppositories) systemic: - brain, heart, circulation, liver, kidney, pancreas, tumours oral - buccal - intestinal - colonic - intravenous - intra-arterial - subcutaneous - intrathecal

Lead optimisation

Medicinal chemistry - library development - development of SAR studies - In silico Screening - chemical synthesis iterative cycles of cynthesis and testing In vitro studies - drug affinity and selectivity - cell disease models - mode of action (MOA) - ADME - lead candidate refinement (on-target pharmacology, off-target pharmacology, safety, PK/PD, disease models) In vivo studies - animal models of diseas states - behavioural studies - functional imaging - ex-vivo studies Development - early development chemistry - pharmacy and safety assessment - Protection of IP (patents)

Specific SAE cases

Northwick Park Tragedy TGN1412 - MAb agonist of CD28 (T-cell receptor) - being developed as a treatment for leukaemia - cytokine release syndrome with multi-organ failure BIA102474-101 - Fatty acid amide hydroxylase (FAAH) inhibitor) .....

Increase oral availability of anticancer drugs

Oral administration ideally: patient-friendly, relatively safe and cheap - efficacy vs toxicity (oral administration rarely feasible) drug transporter inhibitor + cytotoxic drug = better oral availability (and better response in resistant tumour) ivermectin - antiparasitic agent - neurotoxic - 100x higher in abcb1 KO mice elecridar (ABCB1 and ABCG2 inhibitor) + Topotecan (Topoisomerase I inhibitor, anticancer drug) = drastic therapy improvement

New drug introduction scams

Patents - price changes in the cost of a months drug supply - statin switches evergreening - life cycle management - extend the patent life to maintain revenue - examples include packaging, dosing, regimen, route, small changes in active ingredient me toos - slightly modified mimics of existing medicaitons - new agents in a class

General overview of clinical trials

Phase I (First Time in Man or FTIM) - healthy volunteers - safety, pharmacokinetics, pharmacology - 20-80 Phase II (Proof of concept or PoC) - Patients - IIa - pilot trials to detremine safety and efficacy - IIb - larger scale trials to evaluate safety and efficacy - 100-300 Phase III - patients - large scale to evaluate overall risk-benefit - leads into NDA - 1000-3000 Phase IV - post launch - long-term monitoring - more than 1000

Target selection

Potential reward: - unmet need - efficacy of new drug (vs potential harm) - financial Risk - big pharma - biotech - academic Technical elements (drug hunter commitment, technology resources/priorisation, portfolio management, clinical development opinion, competitive inteligence, therapeutic areas) Non-technical (business forecasts, MA in-licensing opportunities, consultancy experts, financial analysis, stragic marketing, management policy/share price)

Therapeutic modalities

Relevant: SME, Biologics, Gene therapy, Cell-based therapy, organ and tissue transplant Less relevant: advie ad counselling, psychological treatments, dietary and nutritional treatments, physical treatments, pharmacological treatments biological and biopharmaceutical

Endpoints

Requirements - appropriate - based on the hypothesis i.e. likely to be altered by the intervention - measurable - clinically relevant - benefit that is detectable by the ptient (objective/subjective) - surrogate: lab measure/imaging/physical sign - frequent: less participants are required to measure an effect of the intervention Composite endpoints - single measure of effect, based on a combination of individual endpoints - useful for drugs that can benefit patients in several ways or component events are infrequent - e.g. cardivascular death, hospitalisation of heart failure,

Signal and sources of signals

Signal = a report or reports of an event with an unknown casual relationship to treatment that is recognised as worthy of further exploration and continued surveillance Sources 1.) Preclinical development - In vitro studies (chemistry, metabolism, receptors, transporters) - animal studies 2.) Clinical development - human studies (adverse events, laboratory data, class effects) - animal studies - in vitro studies 3.) Early after launch - human studies (Phase IIIb/IV; New indications) - Spontaneous Reports - Published literature - Epidemiology 4.) Mature product - published literature - spontaneous case reports - epidemiology

Potential drug targets

Small molecular weight chemical compound (SMOL) - enzymes (inhibitor, activator) - receptors (I, A, agonist, antagonist, modulator, sensitiser) - transcription factors (I, A) - ion channels (I, opener) - transport proteins (I) - protein-protien interface (I) - nucleic acids (alkylation, complexation, intercalation) Biologics (BIOL) - ext. cell. proteins (antibodies) - TM receptors, ext. cell. proteins (recombinant proteins) - cell surface receptor (antibody-drug conjugates) - substrates and metabolites (enzymatic cleavage) Nucleic acids - RNA (siRNA or RNAi)

process of risk management

Stages: 1.) dentification and characterization of the safety profile of the medicinal product 2.) planning of pharmacovigilance activities to characterize risks and identify new risks 3.) planning and implementation of risk minimization and mitigation and assessment of the effectiveness of these activities 4.) document postapproval obligations that have been imposed as a condition of the marketing authorization

Reproductive toxicology

Stages 1.) premating to conception 2.) conception to implantation 3.) implantation to closure of hard palate (organogenesis) 4.) closure of hard palate to end of pregnancy 5.) birth to weaning 6.) weaning to sexual maturity fertility and early embryonic development (in rats) - premating to implantation - gamete production and release - mating behaviour - pre-implantation, implantation and embryo viability embryo-foetal development (rat and rabbit) - 3.) and 4.) - assess effects on pregant female as well as embryo development pre- and postnatal development (in rats) - implantation to weaning (3 to 6) - observations continued to sexual maturity

Preclinical drug target identification - CETP

Starting with a molecular target: cholesterol ester transfer protein 1.) rare mutation identified -> increased function of CETP leads to accelerated atherosclerosis 2.) polymorphism of the CETP gene -> leads to lower serum levels, lower LDL and higher HDL -> linked to exceptional longevity even with statins (lipitor) -> very high residual rates of ischaemic heart disease 3.) CETP inhibitor: Torcetrapib (Pfizer) - good human toxicology - well-tolerated - phaes III trial enrolled from 2005 onwards high expectations 4.) 60% increase in deaths observed among patients taking torcetrapib and otarvastatin vs taking ovarstatin alone 5.) trial stopped, cost to Pfizer was more than 800M

Preclinical drug target identification - PDE5

Starting with molecular target 1.) Pathophysiology ANP causes vasc. muscle relaxation, natriuresis and produces cGMP -> activates vasodilation PDE - breaks cGMP down 2.) assayed in isolated aortic bands and then PDE5 enzymes from rat kidney 3.) PDE5 highly expressed in smooth muscle, but absent from kidneys 4.) lead compounds: Zaprinast, UK-92,480 5.) well-tolerated in phase I studies side effec: erectile dysfunction 6.) new double-blind clinical trials 7.) licensing and launching as viagra (2.9 million US prescriptions)

Disproportionality analysis (DPA) of pharmacovigilance databases

To assess the frequency of specific drug-adverse event combinations against the background of all other drugs and events difficult to identify

Structure of ABC transporters

Transmembrane domains (TMDs) - 2 of them with 6 TM helices - span the membrane and form channels -> determine transport characteristics of substrates Nucleotide binding domains (NBDs) /ABC domains - 2 of them - responsible for binding and hydrolysing ATP via an ATPase -> provides energy for translocation ABCB1: TMD1-NBD1-TMD2-NBD2 ABCC2: TMD0 - L0 -TMD1 - NBD1 - TMD2 - NBD2 TMD0 = 5 helical helical TM fragments ABCG2 - NBD - TMD - reverse order - half-transporter - forms heterodimers

Preclinical Drug target Identification case study - Peptic Ulcer Disease

a break in the inner lining of the stomach, first part of the small intestine 1.) identified the vagus nerve in gastric secretion 2.) histamine, and identification of histamine as a gastricsecretagogue 3.) animal models and experiments with the structure of Histamine -> Na-guanylhistamine 4.) discovery of H2 receptor 5.) Burimamide as a lead compound - poor potency 6.) Further development: Metilamide - agranulocytosis, nephrotoxicity 7.) Development of CIMETIDINE

Classification of Adverse drug reactions

adverse drug event/adverse drug reaction: - injury resulting from the use of a drug - ADE includes harm caused by the drug (ADR and overdoses), harm from the use of the drug (dose reductions or discontinuoations of drug therapy) - harm directly caused by the drug at normal doses during normal uses (prophylaxis, diagnosis, therapy of disease, modification of physiologic function) TypeA/TypeB - predictable adverse events which are commonly dose-dependent, can be mild, moderate or severe - unpredictable, have nothing to do with doses (occurs less often) - influenced by patient-specific factors such as drug allergies or intolerances Serious/non-serious - at any dose: results in death, is life-threatening, requires inpatient hospitalisation or prolongation of existing hospitalisation, results in persistent or significant disability/incapacity, or is a congenital anomaly/birth defect Expected/Unexpected

Sentinel events

any unanticipated event in a healthcare setting resulting in death or serious physical or psychological injury to a patient or patients, not related to the natural course of the patient's illness. - anaphylaxis - serious skin reactions - hepatotoxicity - prolonged QT - acute renal failure - agranulocytosis

Determing disease, targets, candidates

disease: incorrectly functioning part or system of the body resulting from the effect of genetic errors, infection, poison, nutritional deficiency, toxicity or unfavourable environmental factors target: component within a given biochemical pathway, that may be responsible for causing a disease state - receptor on a cell - an ion channel - an enzyme or a transport system candidate molecule: shows promising interactions with the target and is a potential new medicine

In silico toxicology/safety testing

evaluation of the chemical structure - Quantitative structure activity relationship (QSAR) ( mathematical relationship between biological activity and chemical characteristics) -structural alerts e.g. Derek (genotoxicity, carcinogenicity, skin sensitisation, hepatotoxicity, hERG liability, teratogenecity, reproductive toxicity)

Realistically identified targets

human genome - intersection between the number of genes linked to disease and the 'druggable' (30K genes, 3K druggable, 3K disease modifying, 600-1200 both) In reality: GCPRs and Enzymes (hormones and GF, ion channels, nuclear hormone receptors, DNA, unknown) around 200 targets were drugged -> over half 70-80% fall into first two category new target validation is slow

Central problem in drug development

if time, money and human resources were unlimited every prospective drug target or therapeutic innovation for every disease could be pursuade. But time, money and human resources are not unlimited. So where do we put these resources? When to stop a project?

Visibility of drug target

lots of effective drugs already exist chronic medical conditions - academics and pharma is being pressured to address them - multifactorial diseases - hard to identify - lack of applicable models pre-clinically orphan diseases - conditions that affect less than 200k people - cystic fibrosis, Lou Gehrig's disease, and Tourette's syndrome - repurposing

transporter/metabolising enzyme - mediated Drug drug interactions (DDI)

polyspecific transporters are induced/inhibited in parallel with polyspecific drug metabolising enzyme Elecradir (ABCB1 and ABCG2 inhibitor) + Topotecan (Topoisomerase I inhibitor, anticancer drug) = drastic anticancer therapy improvement Ritonavir (efflux transporter inhibito) + Lopinavir (HIV protease inhibitor, AIDS treatment)

Necessity of in human experiments

problems with animal models pathophysiology of the model might be wrong - e.g. myocardial infarction in rats - young animals (most human MIs occur over 50) - no atherosclerosis (an important underlying disease process) - no thrombosis (cause of the myocardial infarction) - no co-morbidities (patients have hypertension or diabetes) - no polypharmacy (patients might be on other drugs) species specific effects of drugs - different therapeutic effect? - different toxic effects? if the new treatment is a device - anatomy of the two species are different

Preclinical drug target identification case study - leptin

starting with gene major problem now and the future -> aims to identify anti-obesity drugs (huge market) 1.) discoveryof leptin -> hormone released by fat cells - secretion proportional to fat stores = ideal drug target 2.) recognition: leptin gene mutation, affected individuals morbidly obese -> treated with leptin infusion 3.) leptin infusion -> no effect on obese people with normal leptin gene some genetic therapies -> may only work for specific mutations

Investigational medicinal product

substances or combinations of substances which administered to humans to investigate: - utility to make a medical diagnosis - utility to restore, correct or modify physiological function in humans investigating an IMP = clinical trial (CTIMP) regulated by EU clinical trials directive IMPs: small molecules, immunoglobulins, vaccines, gene therapy, cell therapy, products from human plasma, radiopharmaceuticals, herbs, homeopathic substances

Types of animal models

system that models physiology - cardiovascular - CNS function - Gastrointestinal system that models pathology - genetic manipulation - drug induced - infection - surgically induced

Pharmacokinetics

the branch of pharmacology concerned with the movement of drugs within the body 3 pharmacokinetics phases - absorption - distribution - elimination 2 pharmacokinetic effectors - transport - metabolism

Safety testing - genotoxicity

the property of chemical agents that damages the genetic information within a cell causing mutations, which may lead to cancer genetic toxicology testing (in vitro mammalian chromosomal aberration test, mammalian erythrocyte micronucleus test, mammalian cell gene mutation test) bacterial reverse mutation test/Ames test option 1.) cytogenetic test for chromosome damage or in vitro mouse lymphoma assay -> in vivo genotoxicity option 2.) in vivio genotoxicity in 2 different tissues (including rodent haemotopoietic cell micronucleus)

Unplanned drug-drug interactions in MDR

unplanned DDI efflux enzyme inhibitors - erythromycin (antibiotic) - verapamil from grapefruit juice (Ca2+ channel blocker) = leads to co-administered drug toxicity efflux transporter enzyme inducers: - rifampicin (antibiotic) - hyperforin (in St John's Wort plant) = leads to co-administered drug undertreatment (decreases oral availability)

Enhancements of pharmacovigilance

with new tools it may be possible to identify signals at an earlier stage than with traditional PV methods. 1.) Epidemiology - Electronic health records - Insurance claims database (designed for payment for medical services, data from multiple US health plans) - Electronic health record database (medical record of a patient held by the provider, use to track patients' care) 2.) Pre-clinical toxicology and pharmacology - exploring associations among chemical descriptors 3.) Clinical trial data - analysing clinical trial data 4.) External literature 5.) Spontaneous data - mining spontaneous data ARTIFICIAL INTELLIGENCE