TABLE 7.

Androgen Receptor Variant 7 Detected by Quantitative Reverse Transcriptase Polymerase Chain Reaction in Circulating Tumor Cells as Both Primary and Acquired Resistance to Abiraterone and Enzalutamide

	Abiraterone (n = 31)		Enzalutamide (n = 31)
	Pretreatment AR-V7–Positive	Pretreatment AR-V7–Negative	Pretreatment AR-V7–Positive	Pretreatment AR-V7–Negative
Patients, n	6	25	12	19
PSA ORR, % (95% CI)	0 (0–46)	68 (46–85)	0 (0–26)	53 (29–76)
p Value	.004		.004
PSA PFS, mo (95% CI)	1.3 (0.9–NR)	5.3 (5.3–NR)	1.4 (0.9–NR)	6.0 (3.8–NR)
HR (95% CI)	16.1 (3.9–66.0)		7.4 (2.7–20.6)
p Value	< .001		< .001
PFS*, mo (95% CI)	2.3 (1.4–NR)	6.3 (6.3–NR)	2.1 (2.0–NR)	6.1 (4.7–NR)
HR (95% CI)	16.5 (3.3–82.9)		8.5 (2.8–25.5)
p Value	< .001		< .001
OS, mo	10.6	NR	5.5	NR
HR (95% CI)	12.7 (1.3–125.3)		6.9 (1.7–28.1)
p Value	.006		.002
	Pretreatment (n = 62)		Pretreatment AR-V7–Negative (n = 42)
	AR-V7–Positive	AR-V7–Negative	Post-Treatment AR-V7–Negative	Post-Treatment AR-V7–Positive
Patients, n	18	44	36	6
ORR, % (95% CI)	0 (0–19)	61 (45–76)	68 (52–81)	17 (4–58)
p Value	< .0001		NA
PSA PFS, mo (95% CI)	1.4 (0.9–2.6)	6.1 (5.3–NR)	6.1 (5.9–NA)	3.0 (2.2–NA)
HR (95% CI)	10.5 (4.7–23.6)		NA
p Value	< .001		NA
PFS*, mo (95% CI)	2.1 (1.9–3)	6.4 (6.1–NR)	6.5 (6.1–NA)	3.2 (3.1–NA)
HR (95% CI)	12.7 (5.1–31.9)		NA
p Value	< .001		NA
OS (95% CI)	9.2 (4.5–NR)	>11.9 (11.9–NR)	NA	NA
HR (95% CI)	8.3 (2.5–27.4)		NA
p Value	< .001		NA

^*Clinical or radiographic; PSA response is defined as ≥50% decline in baseline PSA maintained for ≥4 weeks.

Abbreviations: AR-V7, androgen receptor-variant 7; PSA, prostate-specific antigen; ORR, overall response rate; PFS, progression-free survival; NR, not reached; HR, hazard ratio; OS, overall survival; NA, not available.