A student is testing a new drug to treat a bacterial infection. Before the drug can be given to patients, it must go through several stages of testing. Describe the stages of drug testing that take place before a drug is approved for use in patients, and explain why each stage is necessary.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Scientists developing a new antibiotic must follow a strict testing process to ensure the drug is safe and effective before it is used to treat patients.
Model answer (5 marks)
1. Pre‑clinical testing – carried out in the laboratory using cells, tissues and live animals.
2. It is carried out first to determine whether the drug is toxic or causes harmful side effects before it is given to humans.
3. Clinical testing – starts with healthy human volunteers.
4. A placebo is used in these trials so that results can be compared and the placebo effect ruled out.
5. Clinical testing then proceeds to patients with the disease to confirm the drug is effective and to establish the optimum, safe dose.
2. It is carried out first to determine whether the drug is toxic or causes harmful side effects before it is given to humans.
3. Clinical testing – starts with healthy human volunteers.
4. A placebo is used in these trials so that results can be compared and the placebo effect ruled out.
5. Clinical testing then proceeds to patients with the disease to confirm the drug is effective and to establish the optimum, safe dose.
Examiner tips
- Use the exact terms ‘pre‑clinical’ and ‘clinical’ testing; include placebo and dose optimisation; keep each point short and to the point.
- Show the sequence: pre‑clinical → healthy volunteers → patients; explain the purpose of each stage.
Mark scheme (5 marks)
- Preclinical testing is carried out first, using cells, tissues and/or live animals in a laboratory
- Preclinical testing is necessary to find out whether the drug is toxic / causes harmful side effects before it is given to humans
- Clinical testing follows, initially on healthy human volunteers
- A placebo is used in clinical trials so that results can be compared / to rule out the placebo effect
- Clinical testing on patients with the disease is carried out to check the drug is effective and to determine the optimum / safe dose
Related
- All Eduqas A-Level Biology revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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