LESSON 1 OF 2
From cells to clinical trials
By the end you can
- Describe the stages of research
- Explain the three clinical trial phases
- Know why animal results don't guarantee human results
Lab and animal research
New compounds start in cell studies (in vitro, in a dish) and then animal studies (in vivo, usually mice or rats). Together these are called preclinical research. They show whether something is worth pursuing, but many results don't carry over to people. Bodies are more complex than dishes, and rodents are not small humans.
Clinical trial phases
Phase 1 tests safety in a small group, often tens of people. Phase 2 tests whether it works and looks for side effects in a few hundred. Phase 3 confirms results in hundreds to thousands, usually against a placebo or existing treatment. A phase 2b trial is a larger, more rigorous phase 2 study run before phase 3.
The gold standard is a randomized controlled trial: people are randomly assigned to the compound or a placebo, and ideally nobody knows who got which, which is called blinding. This reduces bias.
Weak evidence to watch for
Case reports, small uncontrolled studies, studies published only as conference abstracts, and research from a single lab group are weaker evidence. Testimonials and online stories aren't research at all.
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Key terms
- In vitro
- Studied in cells or tissues outside a living body.
- In vivo
- Studied in a living organism, such as a mouse.
- Preclinical
- Cell and animal research done before any human trials.
- Randomized controlled trial (RCT)
- A study that randomly assigns people to the compound or a control.
- Placebo
- An inactive substance used for comparison.
- Phase 1/2/3
- The stages of human trials: safety, early effect, large confirmation.
Remember
- Research moves from cells to animals to human trials.
- Phase 3 randomized trials are the strongest evidence.
- Animal results are a starting point, not proof in people.