Table 2.

Parameter estimates for the PSA disease progression model

Description	Parameter	Units	Estimate (RSE) [Shrinkage, %]	Bootstrap (n = 1,000)
Fixed effect parameters				Median	95% PI
Drug effect	θKP	day−1	6000‡	—
Drug inhibition	θKD0	ng·h·l−1 day−1	0.241 (32.6)	0.260	0.136–0.472
~ Days pretreated taxanes*	θKD0-NTRT	—	-4.00 (52.5)	-3.21	-8.96–0.123
Resistance development	θλ	day−1	0.0113 (44.3)	0.00949	0.00341-0.0262
Growth rate	θKG	day−1	0.00879 (12.6)	0.00941	0.00731–0.0112
Baseline PSA	θPSA0	ng/mL	23.2 (16.5)	23.1	17.3–31.6
~ Prior taxane†	θPSA0-PTAX	—	3.23 (27.6)	3.09	1.84–5.33
Interindividual variability variances
Inhibition rate	ωKD0	CV%	127.3 (14) [26]	132	99.5–175
Resistance development a	ωλ	CV%	88.3 (37.5) [40]	110	62.9–189
Growth rate b	ωKG	CV%	53.7 (13.5) [18]	56.3	40.9–70.8
Baseline PSA c	ωPSA0	CV%	130.4 (8.8) [1.0]	128	110–153
Residual variability variance
Proportional error	σprop	CV%	34.2 (27.5) [14]	24.8	18.8–43.4

^*Power relationship

^†proportional relationship

^‡estimate fixed.

^aCorrelation coefficient ωλ∼ω_KD0 = 0.802

^bcorrelation coefficient ω_KG∼ω_KD0 = -0.293; ω_KG∼ω_λ = -0.111

^ccorrelation coefficient ω_PSA0∼ω_λ = -0.094; ω_PSA0∼ω_KG = -0.032.

Individual parameters were defined as: K_D0 = θ_KD0^* (1+(θ_KD-NTRT/720)) ^*exp(η_KD0); K_P = θ_KP ^* exp(η_KP); λ = θ_λ^* exp(η_λ); K_G = θ_KG ^*exp(η_KG); PSA₀= θ_PSA0 ^*θ_PSA0-PTAX ^*exp(η_PSA0); with η_P distributed according to N(0,ω²_P) for parameter P.