DRUG DISCOVERY – NEW DRUG DEVELOPMENT PROCESS BY Dr. BASAVARAJ K. NANJWADE Department of Pharmaceutics K L E UNIVERSITY JN MEDICAL COLLEGE BELGAUM – 590010 E-mail: bknanjwade@yahoo.co.in 09/07/2007 Dept. of Pharmaceutics 1 DRUG • A substance used in the diagnosis, treatment, or prevention of a disease or as a component of a medication recognized or defined by the U.S. Food, Drug, and Cosmetic Act. • A drug is any chemical or biological substance, synthetic or non-synthetic 09/07/2007 Dept. of Pharmaceutics 2 • A drug is anything that affects the way an organism works. • Drugs can be taken to enhance function, such as a student drinking caffeine to enhance alertness. • For now we only consider drugs which are used to cure a disease. 09/07/2007 Dept. of Pharmaceutics 3 Continued • A disease is often thought of as an infection, where a bacteria, virus, or other living thing invades the body. • However, a disease is anything which affects the proper functioning of the body. • It can be an infection, a genetic disorder, or the result of environmental conditions such as malnourishment, poisoning, or stress. 09/07/2007 Dept. of Pharmaceutics 4 Continued • Engineers often find it easy to see the body as a factory. • Individual organs can be seen as machinery. The actual nuts, bolts, screwdrivers, and wrenches that make up all the machinery are the equivalent of proteins, little chunks of organic material that move things around in the body and attach them together. • Most of the work in our body is done by proteins. 09/07/2007 Dept. of Pharmaceutics 5 Continued • The body contains thousands of different kinds of proteins. • The construction of each is determined by the DNA in the nucleus of each cell. • DNA may be thought of as long strings of instructions which code for how each protein is too be built. • The DNA is just a long string of acids that serves as a message about how to make proteins. 09/07/2007 Dept. of Pharmaceutics 6 How Drugs are Developed • The processes of new drug discovery and development are long, complicated and dependent upon the expertise of a wide variety of scientific, technical and managerial groups. • If you are new to the industry, it can prove a significant challenge to understand the significance of your contribution, even if you belong to one of the teams directly involved; for those on the periphery, the problem is magnified to the point where team interactions and efficiency are adversely threatened. 09/07/2007 Dept. of Pharmaceutics 7 Differences and Similarities of Drugs and Medicinal Plants • Today there are at least 120 distinct chemical substances derived from plants that are considered important drug and are currently in use in one or more countries in the world • Some of these drugs are simply a chemical or chemicals extracted from plant materials and put into a capsule, tablet or liquid. • Eg. In Germany a Cynarin drug is manufactured and sold to treat hypertension, liver disorders and highly cholesterol levels. 09/07/2007 Dept. of Pharmaceutics 8 Differences and Similarities of Drugs and Medicinal Plants • The drug is simply this single chemical or an Artichoke liquid extract, that has been concentrated and chemically manipulated to contain a specific amount of this one chemical ; such a preparation is called a standardized extract. • However in the U.S artichoke extracts are available as natural products and sold in health food stores as “dietary supplements” • Some –U.S artichoke products are even standardized to contain a specific amount of cynarin, yet they can still be purchased here as a natural product without a prescription. • There may be little to no difference between the Cynarin drug produce in Germany and the artichoke standardized herbal supplements made in the U.S considering that the same amount of Cynarin is being delivered, dose for dose 09/07/2007 Dept. of Pharmaceutics 9 Need for consumer education about Herbal supplements & Drugs • Consumers find it very frustrating to sort through a lot of ambiguous information put out by natural product manufacturers who cannot legally label their goods with condition-specific. • Stop them in their tracks in the aisles at the health food store saying “ Hey, look at me, if you have high cholesterol. 09/07/2007 Dept. of Pharmaceutics 10 More is Not Always Better • Be careful about dosage amounts • Philosophy of excess: “ if some is good, more is better” 09/07/2007 Dept. of Pharmaceutics 11 Problem of One Vs Several Chemicals • While many drugs have originated from biologically active plant chemicals, and many plants, medicine uses can be attributed to various active chemicals found in them, there is a distinct difference between using a medicinal plant and a chemical drug. • The difference is one that scares most conventionally trained doctors with no training in plants. • Drugs usually consist of a single chemical, whereas medicinal plants can contain 400 or more chemicals. • It’s relatively easy to figure out the activity and side effects of a single chemical. 09/07/2007 Dept. of Pharmaceutics 12 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Acetyldigoxin Cardiotonic Digitalis lanata Adoniside Cardiotonic Adonis vernalis Aescin Anti-inflammatory Aesculus hippocastanum Aesculetin Anti-dysentery Frazinus rhychophylla Agrimophol Anthelmintic Agrimonia supatoria Ajmalicine Circulatory Disorders Rauvolfia sepentina Allantoin Vulnerary Several plants Allyl isothiocyanate Rubefacient Brassica nigra Anabesine Skeletal muscle relaxant Anabasis sphylla Andrographolide Baccillary dysentery Andrographis paniculata Anisodamine Anticholinergic Anisodus tanguticus 09/07/2007 Dept. of Pharmaceutics 13 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Anisodine Anticholinergic Anisodus tanguticus Arecoline Anthelmintic Areca catechu Asiaticoside Vulnerary Centella asiatica Atropine Anticholinergic Atropa belladonna Benzyl benzoate Scabicide Several plants Berberine Bacillary dysentery Berberis vulgaris Bergenin Antitussive Ardisia japonica Betulinic acid Anticancerous Betula alba Borneol Antipyretic, analgesic, antiinflammatory Several plants Bromelain Anti-inflammatory, proteolytic Ananas comosus Caffeine 09/07/2007 CNS Dept. stimulant of Pharmaceutics Camellia sinensis 14 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Camphor Rubefacient Cinnamomum camphora Camptothecin Anticancerous Camptotheca acuminata (+)-Catechin Haemostatic Potentilla fragarioides Chymopapain Proteolytic, mucolytic Carica papaya Cissampeline Skeletal muscle relaxant Cissampelos pareira Cocaine Local anaesthetic Erythroxylum coca Codeine Analgesic, antitussive Papaver somniferum Colchiceine amide Antitumor agent Colchicum autumnale Colchicine Antitumor agent, antigout Colchicum autumnale Convallatoxin Cardiotonic Convallaria majalis 09/07/2007 Curcumin Dept. of Pharmaceutics Choleretic Curcuma longa 15 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Cynarin Choleretic Cynara scolymus Danthron Laxative Cassia species Demecolcine Antitumor agent Colchicum autumnale Deserpidine Antihypertensive, tranquillizer Rauvolfia canescens Deslanoside Cardiotonic Digitalis lanata L-Dopa Anti-parkinsonism Mucuna sp Digitalin Cardiotonic Digitalis purpurea Digitoxin Cardiotonic Digitalis purpurea Digoxin Cardiotonic Digitalis purpurea Emetine Amoebicide, emetic Cephaelis ipecacuanha Ephedrine 09/07/2007 Dept. of Pharmaceutics 16 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Etoposide Antitumor agent Podophyllum peltatum Galanthamine Cholinesterase inhibitor Lycoris squamigera Gitalin Cardiotonic Digitalis purpurea Glaucarubin Amoebicide Simarouba glauca Glaucine Antitussive Glaucium flavum Glasiovine Antidepressant Octea glaziovii Glycyrrhizin Sweetener, Addison's disease Glycyrrhiza glabra Gossypol Male contraceptive Gossypium species Hemsleyadin Bacillary dysentery Hemsleya amabilis Hesperidin Capillary fragility Citrus species 09/07/2007 Dept. of Pharmaceutics 17 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Hyoscyamine Anticholinergic Hyoscyamus niger Irinotecan Anticancer, antitumor agent Camptotheca acuminata Kaibic acud Ascaricide Digenea simplex Kawain Tranquillizer Piper methysticum Kheltin Bronchodilator Ammi visaga Lanatosides A, B, C Cardiotonic Digitalis lanata Lapachol Anticancer, antitumor Tabebuia sp. a-Lobeline Smoking deterrant, respiratory stimulant Lobelia inflata Menthol Rubefacient Mentha species Methyl salicylate Rubefacient Gaultheria procumbens 09/07/2007 Dept. of Pharmaceutics 18 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Monocrotaline Antitumor agent (topical) Crotalaria sessiliflora Morphine Analgesic Papaver somniferum Neoandrographolide Dysentery Andrographis paniculata Nicotine Insecticide Nicotiana tabacum Nordihydroguaiaretic acid Antioxidant Larrea divaricata Noscapine Antitussive Papaver somniferum Ouabain Cardiotonic Strophanthus gratus Pachycarpine Oxytocic Sophora pschycarpa Palmatine Antipyretic, detoxicant Coptis japonica Papain Proteolytic, mucolytic Carica papaya 09/07/2007 Dept. of Pharmaceutics 19 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Phyllodulcin Sweetner Hydrangea macrophylla Physostigmine Cholinesterase Inhibitor Physostigma venenosum Picrotoxin Analeptic Anamirta cocculus Pilocarpine Parasympathomimetic Pilocarpus jaborandi Pinitol Expectorant Several plants Podophyllotoxin Antitumor anticancer agent Podophyllum peltatum Protoveratrines A, B Antihypertensives Veratrum album Pseudoephredrine* Sympathomimetic Ephedra sinica Pseudoephedrine, nor- Sympathomimetic Ephedra sinica Quinidine Antiarrhythmic Cinchona ledgeriana 09/07/2007 Dept. of Pharmaceutics 20 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Qulsqualic acid Anthelmintic Quisqualis indica Rescinnamine Antihypertensive, tranquillizer Rauvolfia serpentina Reserpine Antihypertensive, tranquillizer Rauvolfia serpentina Rhomitoxin Antihypertensive, tranquillizer Rhododendron molle Rorifone Antitussive Rorippa indica Rotenone Piscicide, Insecticide Lonchocarpus nicou Rotundine Analagesic, sedative, traquillizer Stephania sinica Rutin Capillary fragility Citrus species 09/07/2007 Dept. of Pharmaceutics 21 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Salicin Analgesic Salix alba Sanguinarine Dental plaque inhibitor Sanguinaria canadensis Santonin Ascaricide Artemisia maritma Scillarin A Cardiotonic Urginea maritima Scopolamine Sedative Datura species Sennosides A, B Laxative Cassia species Silymarin Antihepatotoxic Silybum marianum Sparteine Oxytocic Cytisus scoparius Stevioside Sweetner Stevia rebaudiana Strychnine CNS stimulant Strychnos nux-vomica 09/07/2007 Dept. of Pharmaceutics 22 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Plant Source Taxol Antitumor agent Taxus brevifolia Teniposide Antitumor agent Podophyllum peltatum a- Antiemetic, decrease Tetrahydrocannabinol( occular tension THC) Cannabis sativa Tetrahydropalmatine Analgesic, sedative, traquillizer Corydalis ambigua Tetrandrine Antihypertensive Stephania tetrandra Theobromine Diuretic, vasodilator Theobroma cacao Theophylline Diuretic, brochodilator Theobroma cacao and others Thymol Antifungal (topical) Thymus vulgaris 09/07/2007 Dept. of Pharmaceutics 23 Plant Based Drugs and Medicines Drug/Chemical Action/Clinical Use Topotecan Antitumor, anticancer agent Camptotheca acuminata Trichosanthin Abortifacient Trichosanthes kirilowii Tubocurarine Skeletal muscle relaxant Chondodendron tomentosum Valapotriates Sedative Valeriana officinalis Vasicine Cerebral stimulant Vinca minor Vinblastine Antitumor, Antileukemic agent Catharanthus roseus Vincristine Antitumor, Antileukemic agent Catharanthus roseus Yohimbine Aphrodisiac Pausinystalia yohimbe Yuanhuacine Abortifacient Daphne genkwa 09/07/2007 Abortifacient Yuanhuadine Dept. of Pharmaceutics Plant Source Daphne genkwa 24 The New Drug Development Process (Steps from Test Tube to New Drug Application Review) 09/07/2007 Dept. of Pharmaceutics 25 Non-clinical Drug Development • Non-clinical drug development is a complex, regulatory-driven process designed primarily to assess the safety and viability of new molecular entities. • Non-clinical, or preclinical, services encompass toxicology, pharmacology, metabolism, bioanalysis, pharmaceutical analysis and biosafety testing in support of non-clinical drug development. 09/07/2007 Dept. of Pharmaceutics 26 Non-clinical Drug Development • A sponsor must first submit data showing that the drug is reasonably safe for use in initial, small-scale clinical studies. • Depending on whether the compound has been studied or marketed previously, the sponsor may have several options for fulfilling this requirement. 1. Compiling existing non-clinical data from past in vitro laboratory or animal studies on the compound 2. Compiling data from previous clinical testing or marketing of the drug in the U.S or another country whose population is relevant to the U.S population 3. Undertaking new preclinical studies designed to provide the evidence necessary to support the safety of administering the compound to humans. 09/07/2007 Dept. of Pharmaceutics 27 Non-clinical Drug Development • During preclinical drug development, a sponsor evaluates the drug’s toxic and pharmacologic effects through in vitro and in vivo laboratory animal testing. • Genotoxicity screening is performed, as well as investigations on drug absorption and metabolism, the toxicity of the drug’s metabolites and the speed with which the drug and its metabolites are excreted from the body. 09/07/2007 Dept. of Pharmaceutics 28 FDA will generally ask 1. Develop a pharmacological profile of the drug 2. Determine the acute toxicity of the drug in at least two species of animals 3. Conduct short-term toxicity studies ranging from 2 weeks to 3 months, depending on the proposed duration of use of the substance in the proposed clinical studies. 09/07/2007 Dept. of Pharmaceutics 29 Subpart E • CFR (Code of Federal Regulations) establishes procedure to expedite the development, evaluation and marketing of new therapies intended to treat people with life-threatening and severelydebilitating illnesses, especially where no satisfactory alternatives exist. 09/07/2007 Dept. of Pharmaceutics 30 Sponsor/FDA Meetings ( Pre-IND) • Prior to clinical studies, the sponsor needs evidence that the compound is biologically active, and both sponsor and the FDA need data showing that the drug is reasonably safe for initial administration to humans. • Meeting at such an early stage in the process are useful opportunities for open discussion about testing phases, data, requirements, and any scientific issues that may need to be resolved prior to IND submission • At these meeting, the sponsor and FDA discuss and agree upon the design of the animal studies needed to initiate human testing 09/07/2007 Dept. of Pharmaceutics 31 Synthesis and Purification • The research process is complicated, time-consuming, and costly and the end result is never guaranteed. • Literally hundreds and sometimes thousands of chemical compounds must be made and tested in an effort to find one that can achieve a desirable result. • FDA estimates that it takes approximately eight and half years to study and test a new drug before it can be approved for the general public. • Computers can be used to simulate a chemical compound and design chemical structures that might work against it. • Enzymes attach to the correct site on a cell’s membrane, which causes the disease. • A computer can show scientists what the receptor site looks like and how one might tailor a compound to block an 09/07/2007 of Pharmaceutics 32 enzyme from attachingDept. there. Animal Testing • Drug companies make every effort to use as few animals as possible and to ensure their humane and proper care. • Generally two or more species ( one rodent, one nonrodent). • Animal testing is used to measure how much of a drug is absorbed into the blood, how it is broken down chemically in the body, the toxicity of the drug and its breakdown products metabolites, and how quickly the drug and its metabolites are excreted from the body 09/07/2007 Dept. of Pharmaceutics 33 Short and Long Term Animal Testing • Short-term testing in animals ranges in duration from 2 weeks to 3 months, depending on the proposed use of the substance. • Long-term testing in animals ranges in duration from a few weeks to several years. - Some animal testing continues after human tests begin to learn whether long-term use of a drug may cause cancer or birth defects. 09/07/2007 Dept. of Pharmaceutics 34 Institutional Review Board • Institutional review boards (IRB) are used to ensure the rights and welfare of people participating in clinical trials both before and during their trial participation. • An IRBs at hospitals and research institutions throughout the country make sure that participants are fully informed and have given their written consent before studies ever begin. • An IRBs are monitored by the FDA to protect and ensure the safety of participants in medical research. • An IRBs must be composed of no less than five experts and lay people with varying background to ensure a complete and adequate review of activities commonly conducted by research institutions. • An IRBs must be composed of people whose concerns are in relevant areas. 09/07/2007 Dept. of Pharmaceutics 35 IND Submitted I. Introduction II. Current requirements and practices III. Clarifications of present IND regulation A. Cover Sheet (FDA Form – 1571) B. Table of contents C. Introductory statement and general investigational plan D. Investigator's brochure E.09/07/2007 Protocols Dept. of Pharmaceutics 36 IND Submitted F. Chemistry, Manufacturing, and Control information 1. Chemistry and manufacturing introduction 2. Drug substance a. A description of the drug substance, including its physical, b. c. d. e. chemical, or biological characteristics The name and address of its manufacturer The general method of preparation of the drug substance The acceptable limits and analytical methods used to assure the identity, strength, quality, and purity of the drug substance. Information to support the stability of the drug substance during the toxicology studies and the proposed clinical study 09/07/2007 Dept. of Pharmaceutics 37 IND Submitted 3. Drug product a. A list of all components, which may include reasonable alternatives for inactive compounds, used in the manufacture of the investigational drug product, including both those components intended to appear in the drug product and those which may not appear, but which are used in the manufacturing process. b. Where applicable, the quantitative composition of the investigational new drug product, including any reasonable variations that may be expected during the investigational stage. c. The name and address of the drug product manufacturer 09/07/2007 Dept. of Pharmaceutics 38 IND Submitted d. A brief, general description of the method of manufacturing and packaging procedures as appropriate for the product. e. The acceptable limits and analytical methods used to assure the identity, strength, quality, and purity of the drug product. f. Information to support the stability of the drug substance during the toxicologic studies and the proposed clinical study(ies) 09/07/2007 Dept. of Pharmaceutics 39 IND Submitted 4. A brief general description of the composition, manufacture, and control of any placebo to be used in the proposed clinical trial. 5. A copy of all labels and labeling to be provided to each investigator. 6. A claim for categorical exclusion from or submission of an environmental assessment. 09/07/2007 Dept. of Pharmaceutics 40 IND Submitted G. Pharmacology and Toxicology information 1. Pharmacology and drug distribution. 2. Toxicology: Integrated summary. 3. Toxicology- Full data tabulation. H. Previous human experience with the investigational drug 09/07/2007 Dept. of Pharmaceutics 41 Phase 1 Clinical Studies • Phase 1 includes the initial introduction of an investigational new drug into human. • Phase 1 studies usually conducted in healthy volunteer. • Phase 1 studies are designed to determine the metabolic and pharmacologic actions of the drug in humans, the side effects associated with increasing doses, and if possible to gain early evidence on effectiveness. 09/07/2007 Dept. of Pharmaceutics 42 Phase 1 Clinical Studies • Phase 1 studies also evaluate drug metabolism, structure-activity relationships, and the mechanism of action in humans. • The total number of subjects included in Phase I studies varies with the drug, but is generally in the range of 20 to 80 09/07/2007 Dept. of Pharmaceutics 43 Phase 2 Clinical Studies • Phase 2 includes the early controlled clinical studies conducted to obtain some preliminary data on the effectiveness of the drug for a particular indication or indications in patients with the disease or condition. • This phase of testing also helps determine the common short-term side effects and risks associated with the drug. • Phase 2 studies are typically well-controlled, closely monitored, and conducted in a relatively small number of patients usually involving several hundred people. 09/07/2007 Dept. of Pharmaceutics 44 Sponsor/FDA Meeting (End of Phase 2) • One month prior to the “end of the Phase 2”, the sponsor should submit the background information and protocols for phase 3 studies. • This information should include data supporting the claim of the new drug product, chemistry data, animal data and proposed additional animal data, results of Phase 1 and 2 studies, statistical methods being used, specific protocols for phase 3 studies, as well as a copy of the proposed labeling for a drug, if available. • This summary provides the review team with information needed to prepare for a productive meeting. 09/07/2007 Dept. of Pharmaceutics 45 Phase 3 Clinical Studies • Phase 3 studies are expanded controlled and uncontrolled trials. • They are performed after preliminary evidence suggesting effectiveness of the drug has been obtained in Phase 2 and are intended to gather the additional information about effectiveness and safety that is needed to evaluate the overall benefit-risk relationship of the drug. 09/07/2007 Dept. of Pharmaceutics 46 Phase 3 Clinical Studies • Phase 3 studies also provide an adequate basis for extrapolating the results to the general population and transmitting that information in the physician labeling. • Phase 3 studies usually include several hundred to several thousand people. • Great care is taken to ensure that this determination is not made in isolation, but reflects current scientific knowledge, agency experience with the design of clinical trials, and experience with the class of drugs under investigation 09/07/2007 Dept. of Pharmaceutics 47 Accelerated Development/ Review • Accelerated development/review is a highly specialized mechanism for speeding the development of drugs that promise significant benefit over existing therapy for serious or life-threatening illnesses for which no therapy exists. • The fundamental element of this process is that manufacturers must continue testing after approval to demonstrate that the drug indeed provides therapeutic benefit to the patient. • If not, the FDA can withdraw the product from the market more easily than usual. 09/07/2007 Dept. of Pharmaceutics 48 Treatment IND • Treatment investigational new drug are used to make promising new drugs available to desperately ill patients as early in the drug development process as possible. • An immediately life-threatening disease means a stage of a disease in which there is a reasonable likelihood that death will occur within a matter of months or in which premature death is likely without early treatment. • Treatment INDs are made available to patients before general marketing begins, typically during Phase 3 studies. • Treatment INDs also allow FDA to obtain additional data on the 09/07/2007 Dept. of Pharmaceutics drug’s safety and effectiveness. 49 Long – Term Testing • Long-term testing in animals ranges in duration from a few weeks to several years. • Some animal testing continues after human tests begin to learn whether long-term use of a drug may cause cancer or birth defects. • Much of this information is submitted to FDA when a sponsor requests to process with human clinical trials. • The FDA reviews the preclinical research data and then makes a decision as to whether to allow the clinical trials to proceed 09/07/2007 Dept. of Pharmaceutics 50 IND Review Process 09/07/2007 Dept. of Pharmaceutics 51 NDA Review Process 09/07/2007 Dept. of Pharmaceutics 52 Generic Drug (ANDA) Review Process 09/07/2007 Dept. of Pharmaceutics 53 OTC Drug Monograph Review Process 09/07/2007 Dept. of Pharmaceutics 54 09/07/2007 Dept. of Pharmaceutics 55