Table 4.

Landmark Analyses of PSA Progression and PSA Response in Trials S9346 and S9916

PSA Data by Analysis Type	Analyses by Trial
	S9346 (HSPC)				S9916 (CRPC)
	HR	95% CI*	Partial r2†‡ (%)	Full r2†§ (%)	HR	95% CI*	Partial r2†‡ (%)	Full r2†§ (%)
PSA progression by landmark time (PCWG2008 [25% + 2])‖¶
Univariate	4.99	4.17 to 6.00	31.5	—	2.06	1.70 to 2.49	8.9	—
Multivariate#	4.39	3.65 to 5.30	26.7	38.8	2.06	1.69 to 2.51	8.3	13.0
Lack of PSA response by landmark time**
Univariate	3.76	3.16 to 4.46	33.5	—	1.76	1.47 to 2.10	6.8	—
Multivariate#	3.58	3.00 to 4.27	30.0	41.6	1.87	1.52 to 2.28	6.6	10.9

Abbreviations: PSA, prostate-specific antigen; HSPC, hormone-sensitive prostate cancer; CRPC, castration-resistant prostate cancer; HR, hazard ratio; PCWG, Prostate Cancer Working Group.

^*All P values < .0001.

^†The r² coefficient of explained randomness was calculated using the method of O'Quigley et al.⁸

^‡For univariate analyses, this is the crude r². For multivariate analyses, this is the partial r² for prostate-specific antigen progression after adjustment for baseline characteristics.

^§The r² for the full multivariate model, including all baseline characteristics.

^‖In trial S9346, the landmark time was the end of the 7-month induction period; in trial S9916, it was 3 months after random assignment.

^¶25% + 2 indicates an increase of prostate-specific antigen by ≥ 25% and ≥ 2 ng/mL.

^#For S9346, model adjusted for age, ethnicity, site of patient registration (Europe v United States/Canada), pretreatment PSA level, bone pain, Gleason sum, and late induction registration. For S9916, model adjusted for treatment arm, age, ethnicity, pretreatment PSA level, SWOG PS, bone pain, prior prostatectomy, and progression of measurable or bone disease.

^**Prostate-specific antigen response was defined in trial S9346 as normalization to ≤ 4 ng/mL at months 6 and 7 (end of induction therapy) and in trial S9916 as a decline of ≥ 30% during the first 3 months on study.