Table 2.

Treatment Patterns in Patients with Metastatic CRPC Who Initiated Abiraterone Acetate or Enzalutamide Therapy During the Observation Period

Treatment parameters	Abiraterone acetate cohort (N = 2591)	Enzalutamide cohort (N = 807)	P valuea
Observation period, mo, mean ± SD [median]	11.0 ± 7.4 [9.6]	8.6 ± 7.1 [6.6]	<.0001b
Patients with an observation period, N (%)
≥3 mo	2188 (84.4)	576 (71.4)	<.0001b
≥6 mo	1745 (67.3)	432 (53.5)	<.0001b
≥9 mo	1373 (53.0)	319 (39.5)	<.0001b
≥12 mo	1032 (39.8)	219 (27.1)	<.0001b
Exposure to treatment, mo, mean ± SD [median]c	7.5 ± 6.1 [5.7]	6.3 ± 5.9 [4.0]	<.0001b
Fills, N, mean ± SD [median]	6.7 ± 5.4 [5.0]	5.4 ± 4.7 [4.0]	<.0001b
Days of supply per fill, mean ± SD [median]	33.5 ± 12.4 [30.0]	32.7 ± 11.2 [30.0]	.0765
Medication possession ratiod
Medication possession ratio, mean ± SD [median]
3 mo	0.97 ± 0.08 [1.00]	0.97 ± 0.08 [1.00]	.0666
6 mo	0.96 ± 0.09 [1.00]	0.94 ± 0.12 [1.00]	.0222b
9 mo	0.95 ± 0.10 [1.00]	0.92 ± 0.15 [1.00]	<.0001b
12 mo	0.95 ± 0.11 [1.00]	0.92 ± 0.16 [1.00]	.0330b
Medication possession ratio ≥80%, N (%)
3 mo	2082 (95.2)	541 (93.9)	.2319
6 mo	1631 (93.5)	383 (88.7)	<.0001b
9 mo	1272 (92.6)	270 (84.6)	<.0001b
12 mo	946 (91.7)	187 (85.4)	.0039b
Nonpersistence, N (%)
3 mo	160 (7.3)	51 (8.9)	.2151
6 mo	406 (23.3)	118 (27.3)	.0780
9 mo	517 (37.7)	141 (44.2)	.0307b
12 mo	516 (50.0)	119 (54.3)	.2435

^aP value was calculated using chi-square tests for categorical variables and t-tests for continuous variables.

^bIndicates P <.05.

^cExposure to treatment was calculated as the number of days between the first fill and the last refill plus the days of supply of the last refill.

^dIf prescription fills overlapped (the start date of the refill started before the end of the previous fill's supply), an adjustment was made such that the prescription start date of the following fill was reset to be the day after the previous fill ended.

CRPC indicates castration-resistant prostate cancer; SD, standard deviation.