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New drug development process


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The process of new drug development.

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New drug development process

  3. 3. INTRODUCTION Development of new drug is very difficult, time consuming & very expensive process. During last 50 years, hundreds of new drugs have been introduced, & many older drugs have been withdrawn. < 1% of compounds that go into test eventually become licensed medicines. To bring a new drug to market requires a good understanding of drug development process & integral role preclinical testing plays
  4. 4. In the past most drugs have been discovered either by identifying the active ingredient from traditional remedies or by serendipitous discovery. But now we know diseases are controlled at molecular and physiological level. Also shape of an molecule at atomic level is well understood. Information of Human Genome. Since the period of patent protection for a new drug(normally 20 years) starts when the compound is registered with the patent office. 5000– 10,000 compounds yield 1 new drug to market.
  5. 5. NEW DRUG  New drug: definition under Schedule Y  New substance, which except during local clinical trials, has not been used ever before in the country.  Drug already approved for certain claims but which is now proposed to be marketed with modified or new claims (indications, dosage, dosage form, route of administration). FDC of two or more drugs, proposed to be combined for first time in a fixed ratio.
  6. 6. REGULATORY AUTHORITIES Authority to grant permission for New Drug to test & market new drug in India rests with “Drugs Controller General of India (DCGI)”, and is given as per Drugs & Cosmetic rules. Schedule Y of Drugs & Cosmetic Rules, regarding investigation of new drug (NDA) gives details of preclinical (animal) data required as also issues guidelines on clinical trials which are required to be carried out for import & /or manufacture of new drug in India.
  7. 7. US :- FDA (Food and Drug Administration) Europe :- EMEA (European Medicines Evaluation Agency) UK :- MHRA (Medicines and Healthcare products Regulatory Agency) Japan :- MHLW(Ministry of Health ,Labour and Welfare)
  8. 8. COMMON WAYS OF DEVELOPING NEW DRUGSRandom screening:- It is a sort of blind hitting procedure where new chemical entities (natural or synthetic) are subjected to series of pharmacological screening procedures to explore different types of biological activity. From natural products. e.g. Plants and animals Studying disease process. Using computers to design new drugs.
  9. 9. STEPS IN NEW DRUG DEVELOPMENT A. Idea or Basic Research B. New drug discovery C. Screening D. Preclinical studies E. Formulation development F. IND application G. Clinical studies H. Official license / Regulations/Marketing
  10. 10. BASIC RESEARCH Start by studying normal & abnormal body functions.  Investigation of each component of the disease (pathophysiology). Look up information obtained in previous research and publication. Find out at which stage we can stop disease progression or development (OUR TARGET!). Search for targeted drug. Isolate the index compound. Perform animal testing to obtain safety data. Approval to test in humans.
  11. 11. NEW DRUG DISCOVERY Pre- discovery To understand the disease. Target Identification Choose a molecule to target with a drug.  Target validation Test the target and confirm its role in the disease.  Drug discovery Find a promising molecule (a “lead compound”) that could become a drug. Lead Optimization  What is/are the symptom(s) ?  What is the cause?  Which is the target organ?  What is/are Biochemical pathway(s)?
  12. 12. TARGET IDENTIFICATION & VALIDATIONOften begins with target identification - choosing a biochemical mechanism involved in a disease condition. Drugs usually act on either cellular or genetic chemicals within our body, known as targets believed to be associated with the disease. Drug candidates are tested for their interaction with drug target. Up to 5000-10000 molecules for each potential drug candidate are subject to rigorous screening process. Once scientists confirm interaction with drug target, they typically validate that target by checking activity against the disease condition for which the drug is
  13. 13. LEAD IDENTIFICATION Lead compound or substance is one that is believed to have potential to treat disease. Laboratory scientists compare known substances with new compounds to determine their likelihood of success. There are a few ways to find a lead compound: Nature: Until recently, scientists usually turned to nature to find interesting compounds for fighting disease. Bacteria found in soil and moldy plants both led to important new treatments. De novo: to advances in chemistry, scientists can also create molecules from scratch. They can use sophisticated computer modeling to predict what type of molecule may work.
  14. 14. High-throughput Screening: This process is the most common way that leads are usually found. Advances in robotics and computational power allow researchers to test hundreds of thousands of compounds against the target to identify any that might be promising. Biotechnology: Scientists can also genetically engineer living systems to produce disease-fighting biological molecules. Leads are sometimes developed as collections, or libraries, of individual molecules that possess properties needed in new drug. Testing is then done on each of these molecules to confirm its effect on drug target.
  15. 15. LEAD OPTIMIZATION (ALTER THE STRUCTURE OF LEAD CANDIDATES TO IMPROVE PROPERTIES) Lead compounds that survive the initial screening are then “optimized,” or altered to make them more effective and safer. By changing the structure of a compound, scientists can give it different properties. For example, they can make it less likely to interact with other chemical pathways in the body, thus reducing the potential for side effects. Hundreds of different variations or “analogues” of the initial leads are
  16. 16. Teams of biologists and chemists work together closely: The biologists test the effects of analogues on biological systems. chemists take this information to make additional alterations that are then retested by the biologists. The resulting compound is the candidate drug. Even at this early stage researchers begin to think about: how the drug will be made, considering formulation (the recipe for making a drug, including inactive ingredients used to hold it together and allow it to dissolve at the right time), delivery mechanism (the way the drug is taken – by mouth, injection, inhaler)
  17. 17. LEAD OPTIMIZATION AT MOLECULAR LEVEL New techniques have revolutionized the ability of researchers to optimize potential drug molecules. Technologies such as magnetic resonance imaging and X-ray crystallography, along with powerful computer modeling capabilities, chemists can actually “see” the target in 3D and design potential drugs to more powerfully bind to the parts of the target where they can be most effective. In addition, new chemistry techniques help scientists to synthesize the new compounds quickly.
  18. 18. NEWER TECHNOLOGIES THAT ARE PIVOTAL TO THE DRUG DISCOVERY AND DEVELOPMENT 1. Medical genetics: Genetic linkage studies are used to shift through the human genome to link genes with particular diseases, while genetic association studies are used to look for known gene sequence in unselected individuals to determine whether they are more common in one disease than another. 2. Combinatorial biosynthesis: It is technique for modelling and building libraries of chemical compounds for considerations as a drug candidates. 3. Robotic high – throughput screening: Using miniaturization and fully automated robotic technology, compounds generated from combinational chemistry, are tested in primary activity screens, identifying lead compounds for further biological testing and chemical optimization.
  19. 19. 4. Bioinformatics : It is information system developed for analysis of biological, particularly genomic data It is used for gene identification and mapping, comparing sequence data in search of similarities, linking genes with their associated proteins and biological functions. Ultimately it is used to identify and validate new targets and to model disease process.
  20. 20.  In the past ,screening of these many compounds could take up to two years.  Using robotic high-throughput screening, this now takes only a few weeks.
  21. 21. CHARACTERISTICS OF IDEAL DRUG CANDIDATE High Potency High Selectivity Good oral Bioavailability Low or no interaction with CYP450 Less or minimal adverse effects Good therapeutic index
  22. 22. SCREENING NCEs are subject to battery of screening tests designed to determine different types of biological activity. Such tests include studies on animal behavior, isolated tissues, intact animals, animal models of the disease. 1 in every 4000-5000 NCEs screened is marketed.
  23. 23. PHARMACOLOGICAL SCREENING OF CANDIDATE MOLECULES Pharmacological observations are made, depending on expected pharmacological properties. e.g. fall in BP, fall in blood glucose, etc. At the cellular level, it is possible to understand the mechanism of action of a drug, whether is acts as: Receptor agonist / antagonist; if so, its affinity and selectivity. Inhibitor of key enzyme, etc. Through this process one can rapidly identify active compounds, antibodies or genes which modulate a particular biomolecular pathway. The results of these experiments provide starting points for
  24. 24. PRECLINICAL TESTING Lab and animal testing to determine if the drug is safe enough for human testing . In order to gain approval for general medical use, the quality, safety and efficacy of any product must be demonstrated. Regulatory authority approval to commence clinical trials is based largely upon preclinical pharmacological and toxicological assessment of the potential new drug in animals. Such preclinical studies can take up to 3 years to complete.
  25. 25. Scientists carry out in vitro and in vivo tests. The U.S. Food and Drug Administration (FDA) requires extremely thorough testing before the candidate drug can be studied in humans. During this stage researchers also must work out how to make large enough quantities of the drug for clinical trials. Techniques for making a drug in the lab on a small scale do not translate easily to larger production. This is the first scale up. The drug will need to be scaled up even more if it is approved for use in the general patient population.
  26. 26. At pre-clinical stage ,the regulatory bodies will generally ask, at a minimum that sponsors(s): Develop a pharmacological profile of drug. Determine the acute toxicity of the drugs in at least two species of animals. Conduct a short-term toxicity studies ranging from 2weeks to 3 months, depending on the proposed duration of use of the substance in the clinical studies. Thus pre-clinical testing Involves: 1. Pharmacology testing. 2. Toxicology testing. 3. Animal pharmacokinetics testing.
  27. 27. THE RANGE OF MAJOR TESTS UNDERTAKEN ON A POTENTIAL NEW DRUG DURING PRECLINICAL TRIALS. Pharmacokinetic profile Pharmacodynamic profile Bioequivalence and bioavailability Acute toxicity Chronic toxicity Reproductive toxicity and teratogenicity Mutagenicity Carcinogenicity Immunotoxicity
  28. 28. PHARMACOKINETICS “What does the body do to the drug ?” Relates to the fate of a drug in the body, particularly its ADME, i.e. its absorption into the body, its distribution within the body, its metabolism by the body, and its excretion from the body. Generally, ADME studies are undertaken in two species, usually rats and dogs. Repeated at various different dosage levels. (Males & females). If initial clinical trials reveal differences in human versus animal model
  29. 29. PHARMACODYNAMICS “What does the drug do to the body ?” Studies deal more specifically with how the drug brings about its characteristic effects. Emphasis in such studies is often placed: Physiological effects. Drug action. Relationship between drug concentration and effect.
  30. 30. TOXICITY TESTING Toxicology studies will be carried out both in vitro and on animal species. Toxicology and safety testing determine the potential risk a compound pose to man and the environment. Dosage levels are explored initially at the stage of animal testing in efficacy and safety models. Most substances are toxic if given at high enough doses: aims of early drug development are to characterize the toxicity of a compound and to find the balance between desired activity and tolerable toxicity. Toxicity studies are done to calculate:  Maximum tolerated dose  Gross Effects, Clinical Chemistries  Gross pathology to Indicate Target Organs  Satisfactory Therapeutic Ratio vis-à-vis Animal Efficacy studies Toxicology studies in preclinical stage are conducted to  Select or reject lead candidate  General indication of suitability  Dose selection and guidance to clinician
  31. 31. TYPES OF TOXICOLOGICAL INVESTIGATIONSAcute toxicity 2 weeks studies in 3-4 species to determine maximum tolerated dose. Sub-acute toxicity 6 months studies in 2 species Chronic toxicity  Up to 12 months studies in rats and non-rodent to determine if adverse effects occur with repeated daily dosing.  Oncology studies o At least 18 months in mice o 2 years in rat  Earlier studies demanded calculation of an LD50 value (i.e. the quantity of the drug required to cause death of 50 per cent of the test animals). Such studies required large quantities of animals, were expensive, and attracted much attention from animal welfare groups.  Nowadays, in most world regions, calculation of the approximate lethal dose is sufficient.
  32. 32. REPRODUCTIVE TOXICITY AND TERATOGENICITYAll reproductive at three different dosage levels (ranging from non- toxic to slightly toxic) to different groups of the chosen target species (usually rodents). Fertility studies aim to assess the nature of any effect of the substance on male or female reproductive function. The drug is administered to males for at least 60 days (one full spermatogenesis cycle). Females are dosed for at least 14 days before they are mated. These reproductive toxicity studies complement teratogenicity studies, which aim to assess whether the drug promotes any developmental abnormalities in the foetus. (usually rats and rabbits)
  33. 33. MUTAGENICITY, CARCINOGENICITY AND OTHER TESTS Mutagenicity tests aim to determine whether the proposed drug is capable of inducing DNA damage, either by inducing alterations in chromosomal structure or by promoting changes in nucleotide base sequence. Mutagenicity tests are usually carried out in vitro and in vivo 18-24 month, often using both prokaryotic and eukaryotic organisms. Longer-term carcinogenicity tests are undertaken, particularly if (a) the product’s likely therapeutic indication will necessitate its administration over prolonged periods few weeks or more . (b) if there is any reason to suspect that the active ingredient or other constituents could be carcinogenic. For many biopharmaceuticals, immunotoxicity tests (i.e. the product’s ability to induce
  34. 34. ACCEPTABLE TOXICITY Now a days, extensive toxicological studies ensure that drugs causing serious toxicity do not reach the market, unless of course the agent concerned has potentially life saving role in treating a diseases. And where no other more suitable drugs are available. At present, HIV infection represents such a serious threat to life that is considered acceptable to use drugs to treat it which rather toxic to human body.
  35. 35. INVESTIGATIONAL NEW DRUG (IND) APPLICATION AND SAFETY After completing pre-clinical testing, the company files an IND with FDA or DCGI in India to begin to test the drug in human. File IND with the FDA before clinical testing can begin; ensure safety for clinical trial volunteers through an Institutional Review Board(IRB). Before any clinical trial can begin, the researchers must file an Investigational New Drug (IND) application with the FDA. The application includes : The results of preclinical work, Candidate drug’s chemical structure how it is thought to work in the body, a listing of any side effects , method of product manufacture and
  36. 36. The IND also provides a detailed clinical trial plan that outlines how, where and by whom the studies will be performed. The FDA or DCGI reviews the application to make sure people participating in the clinical trials will not be exposed to unreasonable risks. All clinical trials must be reviewed and approved by the Institutional Review Board (IRB) at the institutions where the trials will take place. This process includes the development of appropriate informed consent, which will be required of all clinical trial participants. Statisticians and others are constantly monitoring the data as it becomes
  37. 37. The FDA or the sponsor company can stop the trial at any time if problems arise. In some cases a study may be stopped because the candidate drug is performing so well that it would be unethical to withhold it from the patients receiving a placebo or another drug. Finally, the company sponsoring the research must provide comprehensive regular reports to the FDA and the IRB on the progress of clinical trials.
  38. 38. PATENTING The discovery and Lead Optimization of any substance of potential pharmaceutical application is followed by its patenting. A method of synthesis and its biological effects, the better the chances of successfully securing a patent. Thus, patenting may not take place until preclinical trials and phase I clinical trials are completed. Patenting, once successfully completed: 1. it must be proven safe and effective in subsequent clinical trials, 2. be approved for general medical use by the relevant regulatory authorities.
  39. 39. WHAT IS A PATENT AND WHAT IS PATENTABLE? A patent may be described as a monopoly granted by a government to an inventor, such that only the inventor may exploit the invention/innovation for a fixed period of time (up to 20 years). In order to be considered patentable, an invention/innovation must satisfy several criteria: novelty non-obviousness sufficiency of disclosure utility
  40. 40. FORMULATION DEVELOPMENT Pre-formulation Before a drug can formulated, we must known about its physio-chemical properties and behaviour (e.g. its solubility, its crystal structure). These will dictate, the dosage forms in which medicine will be marketed and can be used during drug development investigations. Drug characterizations Pre-formulation studies will attempt to characterize the drug by Spectroscopy, Solubility, melting point, Assay development, Stability, Microscopy, Powder flow and compression properties, Excipient compatibility.
  41. 41. Dosage form design At some stage, a decision needs to be made about the dosage forms for the delivery of the drug (e.g. tablet, capsule). Types of dosage form There are many different dosage forms and they all have their relative advantages and disadvantages. (e.g. Tablets and capsule, Injections and Infusion, Pessaries and suppositories, Solution, Suspension, Elixirs, Ointment, Creams, Paints, Aerosols, Dry powder inhalations, transdermal patches.)
  42. 42. CLINICAL DEVELOPMENT OF DRUG A clinical development plan is a comprehensive plan designed to map out the development of a drug compound from early Phase-1 studies through marketing. The clinical development plan contains a summary of the pre- clinical findings and of market research done for the drug. Phases of clinical research Clinical research is done in four phases(1,2,3&4),each designed to address different questions. Based upon data gathered from pre-clinical testing, the sponsor has estimation of: •The drug’s therapeutic effect and dose levels.
  43. 43. PHASE I CLINICAL TRIALS The main goal of a Phase 1 trial is to discover if the drug is safe in humans. This is a open study conducted in healthy human volunteers (20- 80). In special populations (e.g. for anti-cancer drugs).
  44. 44. In phase I studies regulatory bodies (i.e. FDA)can impose a clinical hold(i.e. prohibit the study from proceeding or stop a trial that has started) for reasons of safety ,or because of sponsor’s failure to accurately disclose the risk of study to investigators. Phase I Trial Address:  How rapidly the drug is absorbed?  Where is the drug distributed in the body?  Which organ or organ system are involved in metabolism of drug?  How quickly is the drug eliminated from the body? FACT: only about 70% of experimental drugs passes Phase I clinical trials.
  45. 45. PHASE II CLINICAL TRIALS Therapeutic exploratory trials. First trial in patients with the disease to be treated. 50-300 patients are used for this study. Objectives Effectiveness of the drug  Common short term side effects and risks with I.N.D. Determine doses and regimens for phase III trials  PK, PD, safety Therapeutic regimens Target populations for further studies in phase III
  46. 46. FACT: only about 35% of experimental drug passes Phase II clinical trial. Phase II Trial address:  What is the minimum effective dose?  What is the maximum tolerated dose?  Is the drug effective in mild, moderate, and severe cases of the disease or condition?  Is the drug effective for all expected indications?
  47. 47. 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
  48. 48. PHASE III CLINICAL TRIAL  Phase III studies are extended controlled and uncontrolled trials. They are performed after preliminary evidence suggesting effectiveness of the drug has been obtained in phase II ,and intended to gather the additional info about effectiveness and safety. It may involve several hundred to several thousand (300-3000)patients and last 1-5 years. Phase III trials involve different patient sub-groups, such as children, the elderly ,and perhaps those with impairments in liver and kidney. Once the phase III completed satisfactory, the drug company to apply marketing Phase III Trial Address:  Overall benefit-risk relationship?  Adverse reaction in a large group of patients over a longer period of exposure?  The ideal dosage regimen?  Should the drug is allowed to be marketed? FACT: only about 25% of a experimental drugs passes Phase III clinical trials.
  49. 49. ORGANIZATIONAL STRUCTURE FOR A TYPICAL PHASE III CLINICAL TRIAL sponsor Steering committee Data monitoring committee[DM C] Contact Research organization [CRO] Data Management Center Clinical Study Site Investigators Data Clarification Forms (DCFs) Data Clarification Forms (DCFs)
  50. 50. CLINICAL TRIAL DESIGN An incredible amount of thought goes into the design of each clinical trial. To provide the highest level of confidence in the validity of results, many drug trials are : Placebo-controlled: Some subjects will receive the new drug candidate and others will receive a placebo. (In some instances, the drug candidate may be tested against another treatment rather than a placebo.) Randomized: Each of the study subjects in the trial is assigned randomly to
  51. 51. Double-blinded: Neither the researchers nor the subjects know which treatment is being delivered until the study is over. This method of testing provides the best evidence of any direct relationship between the test compound and its effect on disease because it minimizes human error. However, in many instances, alternative trial designs are chosen based on ethical or other grounds. In most cases, two groups are considered: control and test. However, these designs can be adapted to facilitate more complex subgrouping.
  52. 52. NEW DRUG APPLICATION (NDA) AND APPROVALOnce all three phases of the clinical trials are complete, the sponsoring company analyzes all of the data. If the findings demonstrate that the experimental medicine is both safe and effective, the company files a New Drug Application (NDA) — which can run 100,000 pages or more — with the FDA requesting approval to market the drug. The NDA includes all of the information from the previous years of work, as well as the proposals for manufacturing and labeling of the new medicine. FDA experts review all the information included in the NDA to determine if it demonstrates that the medicine is safe and effective enough to be approved.
  53. 53. Following rigorous review, the FDA can either 1) approve the medicine, 2) send the company an “approvable” letter requesting more information or studies before approval can be given, or 3) deny approval. Review of an NDA may include an evaluation by an advisory committee, an independent panel of FDA-appointed experts who consider data presented by company representatives and FDA reviewers. Committees then vote on whether the FDA should approve an application, and under what conditions. The FDA is not required to follow the recommendations of the advisory committees, but often does.
  54. 54. PHASE IV CLINICAL TRIAL(POST MARKETING SURVEILLANCE) Research on a new medicine continues even after approval. As a much larger number of patients begin to use the drug, companies must continue to monitor it carefully and submit periodic reports, including cases of adverse events, to the FDA. In addition, the FDA sometimes requires a company to conduct additional studies on an approved drug in “Phase 4” studies. These trials can be set up to evaluate long-term safety or how the new medicine affects a specific subgroup of patients.
  55. 55. WORLD HARMONIZATION OF DRUG APPROVALS The International Conference on harmonization of technical requirement for registration of pharmaceuticals for human use . A collaboration between regulator from US / EU / JAPAN. Produce guidelines on drug development and clinical trial that are accepted across countries. Good starting place for summaries of clinical trial issues.
  56. 56. PHASE ‘0’ MICRODOSING A new approach to obtain human pharmacokinetic information before the usual expensive phase I safety program is conducted is the phase 0 microdosing. It is hypothesized that microdosing will help to reduce or replace the extensive animal testing of compounds for kinetics, which may later be rejected in human studies. Thus, micro-dose studies use minute quantities of drug and are not intended to produce any pharmacologic effect, when administered to humans, and, therefore, may not cause any adverse events also, but may produce useful pharmacokinetic information and help in further
  57. 57. 1/100th of dose anticipated to produce a pharmacological effect. A small dose of your own medicine….. Provides sufficiently useful PK information to decide on confirmatory development (human & animal toxicology) Helps in early de-selection: Cost saving related to manufacturing, scaling up & CTs.
  58. 58. ABBREVIATED NEW DRUG APPLICATION (ANDA) ANDA is submitted to regulatory bodies to obtain the approval to market a generic drug product. It contains data which when, provided for the review and once approved, an applicant may manufacture and market the generic drug product as a low cost alternative. Generic drug applications are termed “abbreviated” cause they are generally not required to include pre-clinical and clinical data to established safety and effectiveness.
  61. 61. CONCLUSION The drug discovery and development process is a long and complicated process. Before any newly discovered drug is placed on the market, it must undergo extensive testing. Each success is built on many, many prior failures. Advances in understanding human biology and disease are opening up exciting new possibilities for breakthrough medicines. At the same time, researchers face great challenges in understanding and applying these advances to the treatment of disease. These possibilities will grow as our scientific knowledge expands and becomes increasingly complex. Research-based pharmaceutical companies are committed to advancing science and bringing new medicines to patients.