TABLE 2.

Product development phases

Research phase	Participant	Number of participants	Duration of the research	Objective of the research
Phase I trials	Healthy volunteers	20–80	A few months	The interaction of the drug within organism is Investigated.
	If a new drug for cancer patients, patients with the same diagnosis.			Tolerability to drug
				Safety
				Tolerability to the increasing doses of the drug, and dose-related adverse effects are monitored.
Phase II trials	The patients with the disease or condition for which the drug was developed.	>100	A few months - 2 years	Effectiveness of the drug is investigated. However it may not be demonstrated with a few patients.
				Safety data are provided.
Phase III trials	The patients with the disease or condition for which the drug was developed.	300–3000	1–4 years	Greater efficacy and safety data are provided.
				Adverse effects seen less frequently in previous studies may be detected.
				Since they are long-term studies, obtained results provide more comprehensive data.
Phase IV trials	The patients with the disease or condition for which the drug was developed.	>1000	Years	Includes postmarketing studies after licensing the drug or the device by a health authority.
				They are postmarketing safety surveillance studies.