LOWER DOSES MIGHT INCLUDE ONE-
HALF AND ONE-QUARTER OF THE MTD
•
MUCH CONTROVERSY ABOUT BASIS FOR
SELECTION OF DOSES TO BE TESTED
•
STUDY PARAMETERS INVESTIGATED
INCLUDE EXTENSIVE HISTOPATHOLGY
CANCER BIOASSAY
Generally, are control group and three Tx
groups per sex
•
High dose group should approximate MTD*
•
MTD* = Highest Practical Dose which can be
administered experimentally without affecting overall
survival
•
N.B.: Dose Selection is NOT intended to approximate
anticipated human exposure level.
#50
#50
#50
#50-100
HIGH (4x)
MEDIUM (2x)
LOW (x)
CONTROL
Approximate Number of Animals Required for 95%
Confidence Interval Equal to Size of the Effect
(Spontaneous Background Rate = 0.01)
40
+/-.10
.10
.01
.11
ED 10
1,100
+/-.01
.01
.01
.02
ED 1
80,000
+/-.001
.001
.01
.011
ED.001
Approximate
sample size
(each)
(C.I.)
95%
Excess
Prop. of
Animals with
tumors control
Treated
Case
