Core2: Types of clinical trials

🧪 High-yield / 要点：Clinical trials progress from Phase 1 safety → Phase 2 dose/efficacy → Phase 3 confirmation/comparison → Phase 4 post-market safety.

Purpose / 目的

• Clinical trials evaluate safety and efficacy of new drugs/therapies in humans.
• Each phase answers a different clinical question before or after approval.

Phases / 各相

Phase	Typical subjects	Main goal	Key question
Phase 1	Small group; usually healthy volunteers	Safety, toxicity, PK/PD	Is it safe?
Phase 2	Several hundred patients	Optimal dose/regimen + preliminary efficacy	Does it work in patients?
Phase 3	Several thousand patients	Confirm safety/efficacy; compare with placebo or standard care	Is it better/safe enough for approval?
Phase 4	Post-marketing real-world patients	Long-term safety and effectiveness	What happens after approval?

Examples / 例

• Phase 1：new cancer drug → safety/toxicity ± tumor effect.
• Phase 2：Alzheimer drug → dose/regimen + cognitive effect.
• Phase 3：diabetes drug → compare with current standard care.
• Phase 4：antipsychotic → long-term safety/efficacy in schizophrenia.

Remember / 覚え方

• 1 = Safety
• 2 = Dose + early efficacy
• 3 = Confirm + compare
• 4 = Real-world monitoring