First-Line Doublet Chemotherapy for Metastatic Triple-Negative Breast Cancer: Circulating Tumor Cell Analysis of the tnAcity Trial

Figures & data

Table 1 Patient Baseline Characteristics in the Main Analysis of ≥1 Circulating Tumor Cell

Characteristic	Group 1 (+ + +) n = 24	Group 2 (+ ± ±) n = 54	Group 3 (−) n = 48
Age, median (range), years	57.0 (27–71)	56.0 (27–74)	56.5 (31–82)
<65, n (%)	15 (62.5)	42 (77.8)	32 (66.7)
≥65, n (%)	9 (37.5)	12 (22.2)	16 (33.3)
Baseline ECOG PS, n (%)
0	15 (62.5)	30 (55.6)	31 (64.6)
1	9 (37.5)	24 (44.4)	16 (33.3)
2	0	0	1 (2.1)
Race, n (%)
White	18 (75.0)	49 (90.7)	37 (77.1)
Black/African American	4 (16.7)	3 (5.6)	7 (14.6)
Not collected or reported	2 (8.3)	2 (3.7)	4 (8.3)
Region, n (%)
North America	13 (54.2)	33 (61.1)	23 (47.9)
Western Europe	11 (45.8)	20 (37.0)	25 (52.1)
Australia	0	1 (1.9)	0
Disease-free interval, n (%)
≤1 year	7 (29.2)	12 (22.2)	14 (29.2)
>1 year	17 (70.8)	41 (75.9)	34 (70.8)
Triple negative at primary diagnosis, n (%)	17 (70.8)	45 (83.3)	35 (72.9)
Site of metastasis, n (%)
Bone	12 (50.0)	21 (38.9)	13 (27.1)
Breast	7 (29.2)	18 (33.3)	7 (14.6)
Liver	9 (37.5)	17 (31.5)	10 (20.8)
Lung/thoracic	11 (45.8)	33 (61.1)	35 (72.9)
Lymph node(s)	18 (75.0)	45 (83.3)	28 (58.3)
Skin/soft tissue	5 (20.8)	10 (18.5)	8 (16.7)
Other	4 (16.7)	9 (16.7)	10 (20.8)
Abdomen/peritoneal	2 (8.3)	2 (3.7)	0
Prior taxane treatment, n (%)	17 (70.8)	29 (53.7)	33 (68.8)

Abbreviation: ECOG PS, Eastern Cooperative Oncology Group performance status.

Table 2 Median Circulating Tumor Cell Values at Each Assessment

Assessment, Median (Range), CTCs/7.5 mL Blood	Group 1 (+ + +)	Group 2 (+ ± ±)	Group 3 (−)
Baseline	n = 24	n = 54	n = 48
21.5 (0.5–478.5)	5.0 (0.5–1211.5)	0
Cycle 3	n = 18	n = 52	n = 46
3.0 (0.5–169.0)	0 (0–3.0)	0 (0–19.0)
Cycle 5	n = 14	n = 50	n = 24
9.8 (0.5–1380.0)	0 (0–17.5)	0 (0–3.0)

Abbreviation: CTC, circulating tumor cell.

Table 3 Response by Change in Circulating Tumor Cell (CTC) Levels from Baseline in the Main Analysis of ≥1 CTC

Response, n (%)	Group 1 (+ + +) n = 24	Group 2 (+ ± ±) n = 54	Group 3 (−) n = 48
Overall response rate	7 (29.1)	43 (79.6)	21 (43.8)
Complete response	1 (4.2)	9 (16.7)	3 (6.3)
Partial response	6 (25.0)	34 (63.0)	18 (37.5)

Figure 1 Efficacy outcomes by change in circulating tumor cell levels from baseline. Kaplan–Meier plots of (A) PFS and (B) OS.

Notes: Group 1 (+ + +), elevated at baseline and elevated postbaseline; Group 2 (+ ± ±), elevated at baseline and cleared postbaseline (cycle 3 and/or cycle 5); Group 3 (−), no CTCs detected at baseline. ^a vs Group 1.

Abbreviations: HR, hazard ratio; OS, overall survival; PFS, progression-free survival.

Figure 2 Efficacy outcomes by the absence or presence of circulating tumor cells at baseline. Kaplan–Meier plots of (A) PFS and (B) OS.

Abbreviations: CTC, circulating tumor cell; HR, hazard ratio; OS, overall survival; PFS, progression-free survival.

Table 4 PFS by Treatment Arm and Change in Circulating Tumor Cell (CTC) Levels from Baseline in the Main Analysis of ≥1 CTC

Treatment	CTC Group	n (%)	Median PFS, Months
nab-P/C	Group 1 (+ + +)	4 (8.9)	NE
	Group 2 (+ ± ±)	27 (60.0)	8.94
Group 3 (−)	14 (31.1)	4.37
nab-P/G	Group 1 (+ + +)	11 (28.2)	4.24
	Group 2 (+ ± ±)	11 (28.2)	7.92
Group 3 (−)	17 (43.6)	8.75
G/C	Group 1 (+ + +)	9 (21.4)	3.52
	Group 2 (+ ± ±)	16 (38.1)	8.52
Group 3 (−)	17 (40.5)	5.65

Abbreviations: C, carboplatin; CTC, circulating tumor cell; G, gemcitabine; nab-P, nab-paclitaxel; NE, not evaluable; PFS, progression-free survival.