TABLE 2.
Concentration-response model for opioid abstinence in the phase 3 study.
| Parameter | Description | Estimate (RSE%) | IIV (RSE%)# |
|---|---|---|---|
| α | Intercept at logit level (300/300 mg and PBO) | −3.30 (16) | 2.64 (6.0) |
| Emax | Maximal BUP effect | 4.86 (9.7) | 38.7 (32) |
| EC50 | BUP concentration yielding 50% of Emax | 1.21 (44) | 151 (0.39) |
| βα (300/100) | Relative intercept for 300/100 mg compared to 300/300 mg and PBO | 0.794 (10) | − |
| βα (OPRD1 TC) | Fractional change in α for OPRD1 TC genotype (rs678849) | 0.133 (150) | − |
| βα (OPRD1 TT) | Fractional change in α for OPRD1 TT genotype (rs678849) | 0.309 (92) | − |
| βEC50 (INJUSE) | Fractional increase in EC50 for use of opioids by injectable route at baseline | 2.57 (47) | − |
| βEC50 (OPRD1 TC) | Fractional decrease in EC50 for OPRD1 TC genotype (rs678849) | −0.713 (19) | − |
| βEC50 (OPRD1 TT) | Fractional decrease in EC50 for OPRD1 TT genotype (rs678849) | −0.937 (4.0) | − |
| βEC50 (RACE) | Fractional decrease in EC50 for African Americans | −0.113 (910) | − |
| βEmax (EMPLY) | Fractional increase in Emax for employed participants at baseline | 0.427 (37) | − |
| βEmax (RACE) | Fractional decrease in Emax for African Americans | −0.311 (31) | − |
# IIV was modeled assuming a normal distribution for α (SD shown) and log-normal distributions for Emax and EC50 (CV% shown). For log-normal distributions, CV% was calculated as where was the variance of the related subject-specific random effect.
BUP, buprenorphine; CV, coefficient of variation; IIV, interindividual variability; PBO, placebo; RSE, relative standard error; SD, standard deviation.