Table 3.
Parameter estimates of parametric Weibull survival models
| Description | Estimates (RSE) | P-value* | ||
|---|---|---|---|---|
| Intercept | Coefficient | log(Scale) | ||
| Base model | 6.556 (1.3) | — | -0.483 (23.1) | — |
| Univariate models [unit] | ||||
| Prior taxanes [0,1] | 6.622 (1.7) | -0.149 (110) | -0.484 (22.9) | 0.3632 |
| ECOG score [0, 1, 2] | 6.711 (1.7) | -0.344 (46.8)a -0.681 (52.9)b | -0.528 (21.1) | 0.0130 |
| Age [years] | 7.535 (8.1) | -0.014 (60.3) | -0.489 (22.6) | 0.0936 |
| log (TTN) [days] + 1) | 6.433 (1.4) | 0.091 (45.1) | -0.507 (21.7) | 0.0265 |
| log (PSA0 [ng/mL]) | 7.352 (3.6) | -0.186 (29.1) | -0.560 (19.9) | 0.0006 |
| log (CFB [%]) | 6.880 (3.1) | 0.206 (56.7) | -0.505 (21.9) | 0.0779 |
| log (PSAAUC [ng*h/ml]+ 1) | 6.349 (1.9) | 0.050 (49.9) | -0.494 (22.2) | 0.0486 |
| log (KG [day−1]) | 6.798 (2.1) | 0.155 (42.9) | -0.492 (22.3) | 0.0198 |
| log (KD [day−1]) | 6.798 (2.1) | 0.429 (42.9) | -0.492 (22.3) | 0.0145 |
| Multivariate model [unit] | ||||
| log(kG [day−1]) | 4.987 (16.1) | -0.482 (34.7) | -0.644 (16.8) | <0.0001 |
| log(PSA0 [ng/ml]) | -0.144 (36.8) | |||
| ECOG [0, 1, 2] | -0.313 (46.2)* -0.428 (75.3)* | |||
| log (Tnadir [days] + 1) | 0.049 (75.2) |
*
Likelihood ratio test, compared to base model.
a
ECOG = 1
b
ECOG = 2.
RSE, relative standard error (%); PSA, prostate-specific antigen; PSA0, predicted individual predicted baseline level of PSA; PSAAUC, AUC under the PSA-time curve; CFB, relative maximum change from baseline (%); TTN, time (days) to PSA nadir; KD, PSA growth inhibition rate. The survival function S is given by: S=1-(shape/scale)*(t/scale)(shape-1) with scale=(exp(Intercept+βn*covn +(..) + βn*covn)) for covariate n and its associate regression coefficient βn.