TABLE 2

Parameter estimates of the exposure–response model in rats, monkeys, and humans

Emax in human was estimated using a logistic function (Emax= elogit/1+ elogit).

ParameterEstimates (RSE%)
RatMonkeyHuman
Emax1 fixed1 fixed0.670
Logit for Emax0.707 (16.3)
EC50 (ng/ml)0.196 (22.7)0.416 (29.3)0.292 (7.60)
Hill1.50 (7.33)1.71 (26.3)2.44 (8.44)
E0 (ng/mla or ng×h/mlb)1170 (8.47)a78.9 (11.2)b50.7 (9.90)b
ω2 Logit for Emax0.520 (51.3)
ω2 EC500.693 (48.5)
ω2 E00.219 (30.0)
σ2 Proportional0.195 (28.3)0.128 (29.0)0.0260 (14.0)
  • ω2, interindividual variance estimate for each parameter; σ2, proportional residual error variance; RSE%, relative standard error (standard error as a percentage of estimate).