Clinical trials

• Clinical trials


  Assess the safety and efficacy of any potential new therapeutic 'intervention' in its intended target species
• Clinical trials are prospective rather than retrospective in nature, i.e. participants receiving the intervention are followed forward with time
• Clinical trials phases


  1. Phase I: Drug administered to small group of healthy volunteers to establish pharmacological properties and safety

  2. Phase II: Assess safety and effectiveness of drug in volunteer patients

  3. Phase III: Assess safety and efficacy characteristics of drug in greater detail with hundreds/thousands of patients
• Safe and effective (in clinical trials)

  Favorable risk:benefit ratio, where benefits outweigh risks. Acceptable level of efficacy defined, e.g. drug effective in 25% of patients
• If observed efficacy is below minimal acceptable level, clinical trials are normally terminated
• Phase IV clinical trials

  Assess long-term safety of drug, particularly if administered for longer periods than phase III trials
• Extensive early development work is essential to ensure production process for trial material is suitable for final-scale commercial manufacture
• Clinical trial design


  • Must have control group for comparison
  • Size limited by factors like financial resources, target population size, eligible participants willing to take part
• Randomized control clinical trial


  Participants randomly assigned to control or test group, with concurrent testing. Removes potential for bias and ensures statistical validity
• Historical control trials


  All participants receive new drug, results compared to previous trial data. Avoids ethical issues but vulnerable to bias
• Clinical trial phases and timeline


  • Preclinical testing (3.5 years)
  • Phase I (1 year)
  • Phase II (2 years)
  • Phase III (3 years)
  • FDA review and approval (2.5 years)
  • Total 12 years
• 5,000 compounds evaluated, 5 enter trials, 1 approved
• Patenting


  Products of nature can be patented if 'hand of man' has played a role in developing the product, e.g. purification, modification
• Patenting of genes and DNA sequences is allowed if they can be used for specific purposes like diagnostics or coding medically valuable proteins
• Regulatory authorities


  Governments pass laws to tightly control all aspects of pharmaceutical activity, enforced by regulatory agencies
• FDA


  • Mission is to protect public health
  • Regulates products worth $1 trillion annually
  • Employs over 9,000 people, $1 billion budget
  • Responsibilities include assessing preclinical/clinical data, approving manufacturing facilities, ensuring blood supply safety