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Introduction
1. Anatomy
2. Microbiology
3. Physiology
4. Pathology
5. Pharmacology
6. Immunology
7. Biochemistry
8. Cell and molecular biology
9. Biostatistics and epidemiology
9.1 Measure of disease frequency
9.2 Measures of health status
9.3 Reportable diseases
9.4 Variables and distributions
9.5 Standard deviation and confidence intervals
9.6 Measures of association
9.7 Types of study design
9.8 Bias
9.9 Hypothesis testing
9.10 Sensitivity, specificity and predictive values
9.11 Phases of drug approval
9.12 Doctor patient relationships, ethics and decision-making capacity
9.13 Additional information
10. Genetics
11. Behavioral science
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9.11 Phases of drug approval
Achievable USMLE/1
9. Biostatistics and epidemiology

Phases of drug approval

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Phase Description
I (drug discovery and development) Studies are conducted to determine the drug’s efficacy, appropriate dosage, methods of administration, side effects, metabolism, excretion, and potential drug interactions.
II (preclinical studies) The drug is tested in vivo and/or in vitro to determine its potential for harm (toxicity).
III (clinical research) Phase 1: Involves 20-100 study participants and lasts several months. Used to determine the safety and dosage of the drug. About 70% of these drugs move on to the next clinical research phase.
Phase 2: Involves up to several hundred people with the condition of interest. Lasts from a few months to two years. Used to monitor the drug’s efficacy and to identify side effects. Only 30% of drugs move to the next phase.
Phase 3: Involves 300-3000 volunteers and can last up to four years. Used to continue monitoring the drug’s efficacy and to evaluate longer-term adverse reactions. About 25%-30% of drugs move to the next phase.
Phase 4: Involves several thousand volunteers who have the disease or condition. Continues to monitor safety and efficacy. If a drug passes this phase, it goes on to FDA review.
IV (FDA review) Takes 6-10 months.
V (post-market monitoring) The drug is available for sale, and safety monitoring continues.

Phase I: Drug discovery and development

  • Determine drug efficacy and dosage
  • Study administration methods, side effects, metabolism, excretion
  • Assess potential drug interactions

Phase II: Preclinical studies

  • Test drug in vivo and/or in vitro
  • Evaluate toxicity and potential for harm

Phase III: Clinical research

  • Phase 1: 20-100 participants, several months
    • Assess safety and dosage
    • ~70% progress to next phase
  • Phase 2: Up to several hundred participants, months to 2 years
    • Monitor efficacy, identify side effects
    • ~30% progress to next phase
  • Phase 3: 300-3000 participants, up to 4 years
    • Continue efficacy monitoring, evaluate long-term adverse reactions
    • ~25-30% progress to next phase
  • Phase 4: Several thousand participants with disease/condition
    • Ongoing safety and efficacy monitoring
    • Success leads to FDA review

Phase IV: FDA review

  • Duration: 6-10 months

Phase V: Post-market monitoring

  • Drug available for sale
  • Continued safety monitoring
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Phases of drug approval

Phase Description
I (drug discovery and development) Studies are conducted to determine the drug’s efficacy, appropriate dosage, methods of administration, side effects, metabolism, excretion, and potential drug interactions.
II (preclinical studies) The drug is tested in vivo and/or in vitro to determine its potential for harm (toxicity).
III (clinical research) Phase 1: Involves 20-100 study participants and lasts several months. Used to determine the safety and dosage of the drug. About 70% of these drugs move on to the next clinical research phase.
Phase 2: Involves up to several hundred people with the condition of interest. Lasts from a few months to two years. Used to monitor the drug’s efficacy and to identify side effects. Only 30% of drugs move to the next phase.
Phase 3: Involves 300-3000 volunteers and can last up to four years. Used to continue monitoring the drug’s efficacy and to evaluate longer-term adverse reactions. About 25%-30% of drugs move to the next phase.
Phase 4: Involves several thousand volunteers who have the disease or condition. Continues to monitor safety and efficacy. If a drug passes this phase, it goes on to FDA review.
IV (FDA review) Takes 6-10 months.
V (post-market monitoring) The drug is available for sale, and safety monitoring continues.
Key points

Phase I: Drug discovery and development

  • Determine drug efficacy and dosage
  • Study administration methods, side effects, metabolism, excretion
  • Assess potential drug interactions

Phase II: Preclinical studies

  • Test drug in vivo and/or in vitro
  • Evaluate toxicity and potential for harm

Phase III: Clinical research

  • Phase 1: 20-100 participants, several months
    • Assess safety and dosage
    • ~70% progress to next phase
  • Phase 2: Up to several hundred participants, months to 2 years
    • Monitor efficacy, identify side effects
    • ~30% progress to next phase
  • Phase 3: 300-3000 participants, up to 4 years
    • Continue efficacy monitoring, evaluate long-term adverse reactions
    • ~25-30% progress to next phase
  • Phase 4: Several thousand participants with disease/condition
    • Ongoing safety and efficacy monitoring
    • Success leads to FDA review

Phase IV: FDA review

  • Duration: 6-10 months

Phase V: Post-market monitoring

  • Drug available for sale
  • Continued safety monitoring