<Table> <Tr> <Th colspan="7"> Summary of clinical trial phases </Th> </Tr> <Tr> <Th> Phase </Th> <Th> Primary goal </Th> <Th> Dose </Th> <Th> Patient monitor </Th> <Th> Typical number of participants </Th> <Th> Success rate </Th> <Th> Notes </Th> </Tr> <Tr> <Td> Preclinical </Td> <Td> Testing of drug in non-human subjects , to gather efficacy , toxicity and pharmacokinetic information </Td> <Td> unrestricted </Td> <Td> scientific researcher </Td> <Td> not applicable ( in vitro and in vivo only ) </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Phase 0 </Td> <Td> Pharmacokinetics ; particularly , oral bioavailability and half - life of the drug </Td> <Td> very small , subtherapeutic </Td> <Td> clinical researcher </Td> <Td> 10 people </Td> <Td> </Td> <Td> often skipped for phase I </Td> </Tr> <Tr> <Td> Phase I </Td> <Td> Testing of drug on healthy volunteers for safety ; involves testing multiple doses dose - ranging </Td> <Td> often subtherapeutic , but with ascending doses </Td> <Td> clinical researcher </Td> <Td> 20 -- 100 normal healthy volunteers ( or for cancer drugs , cancer patients ) </Td> <Td> approximately 70 % </Td> <Td> determines whether drug is safe to check for efficacy </Td> </Tr> <Tr> <Td> Phase II </Td> <Td> Testing of drug on patients to assess efficacy and side effects </Td> <Td> therapeutic dose </Td> <Td> clinical researcher </Td> <Td> 100 -- 300 patients with specific diseases </Td> <Td> approximately 33 % </Td> <Td> determines whether drug can have any efficacy ; at this point , the drug is not presumed to have any therapeutic effect whatsoever </Td> </Tr> <Tr> <Td> Phase III </Td> <Td> Testing of drug on patients to assess efficacy , effectiveness and safety </Td> <Td> therapeutic dose </Td> <Td> clinical researcher and personal physician </Td> <Td> 300 -- 3,000 patients with specific diseases </Td> <Td> 25 -- 30 % </Td> <Td> determines a drug 's therapeutic effect ; at this point , the drug is presumed to have some effect </Td> </Tr> <Tr> <Td> Phase IV </Td> <Td> Postmarketing surveillance -- watching drug use in public </Td> <Td> therapeutic dose </Td> <Td> personal physician </Td> <Td> anyone seeking treatment from their physician </Td> <Td> N / A </Td> <Td> watch drug 's long - term effects </Td> </Tr> </Table>
<Table> <Tr> <Th colspan="7"> Summary of clinical trial phases </Th> </Tr> <Tr> <Th> Phase </Th> <Th> Primary goal </Th> <Th> Dose </Th> <Th> Patient monitor </Th> <Th> Typical number of participants </Th> <Th> Success rate </Th> <Th> Notes </Th> </Tr> <Tr> <Td> Preclinical </Td> <Td> Testing of drug in non-human subjects , to gather efficacy , toxicity and pharmacokinetic information </Td> <Td> unrestricted </Td> <Td> scientific researcher </Td> <Td> not applicable ( in vitro and in vivo only ) </Td> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Phase 0 </Td> <Td> Pharmacokinetics ; particularly , oral bioavailability and half - life of the drug </Td> <Td> very small , subtherapeutic </Td> <Td> clinical researcher </Td> <Td> 10 people </Td> <Td> </Td> <Td> often skipped for phase I </Td> </Tr> <Tr> <Td> Phase I </Td> <Td> Testing of drug on healthy volunteers for safety ; involves testing multiple doses dose - ranging </Td> <Td> often subtherapeutic , but with ascending doses </Td> <Td> clinical researcher </Td> <Td> 20 -- 100 normal healthy volunteers ( or for cancer drugs , cancer patients ) </Td> <Td> approximately 70 % </Td> <Td> determines whether drug is safe to check for efficacy </Td> </Tr> <Tr> <Td> Phase II </Td> <Td> Testing of drug on patients to assess efficacy and side effects </Td> <Td> therapeutic dose </Td> <Td> clinical researcher </Td> <Td> 100 -- 300 patients with specific diseases </Td> <Td> approximately 33 % </Td> <Td> determines whether drug can have any efficacy ; at this point , the drug is not presumed to have any therapeutic effect whatsoever </Td> </Tr> <Tr> <Td> Phase III </Td> <Td> Testing of drug on patients to assess efficacy , effectiveness and safety </Td> <Td> therapeutic dose </Td> <Td> clinical researcher and personal physician </Td> <Td> 300 -- 3,000 patients with specific diseases </Td> <Td> 25 -- 30 % </Td> <Td> determines a drug 's therapeutic effect ; at this point , the drug is presumed to have some effect </Td> </Tr> <Tr> <Td> Phase IV </Td> <Td> Postmarketing surveillance -- watching drug use in public </Td> <Td> therapeutic dose </Td> <Td> personal physician </Td> <Td> anyone seeking treatment from their physician </Td> <Td> N / A </Td> <Td> watch drug 's long - term effects </Td> </Tr> </Table>
when is a drug studied in patients who have the condition that the drug is intended to treat
when is a drug studied in patients who have the condition that the drug is intended to treat
Phase I Phase II Phase III Phase IV
Phase I Phase II Phase III Phase IV