4.13—Development of drug testing

Drug testing asks two different questions: is a treatment safe, and does it work better than a comparator? Modern development moves from laboratory and animal evidence to controlled clinical phases.

Phase 1 uses a small group to study dose and side effects; Phase 2 tests effectiveness in patients; Phase 3 compares the new drug with an existing treatment in a larger group. Placebos estimate expectation effects, and double blinding reduces observer and participant bias.

William Withering’s digitalis “soup” illustrates early dose-finding without modern controls. A current trial can compare a treatment with a placebo or existing drug while neither patient nor clinician knows the allocation.

A later phase is not automatically proof that every patient benefits. Sample size, comparator, blinding, side effects and outcome measures determine what the evidence supports.