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Table 1 Biomarker status at baseline among patients in the intent-to-treat population of the MARIANNE study

From: Relationship between tumor biomarkers and efficacy in MARIANNE, a phase III study of trastuzumab emtansine ± pertuzumab versus trastuzumab plus taxane in HER2-positive advanced breast cancer

  Trastuzumab + taxane (Control) (N = 365)a T-DM1 (T-DM1) (N = 367)a T-DM1 + pertuzumab (T-DM1 + P) (N = 363)a
HER2 mRNA
 n (%) 330 (90) 339 (92) 330 (91)
 Median (range) 57.28 (1.9–4182.1) 56.89 (0.9–3615.6) 61.61 (2.1–3281.2)
HER2 status, n (%)
 ISH-positive/IHC 3+ 294 (81) 305 (83) 295 (81)
 ISH-positive/IHC 2+ 27 (7) 25 (7) 27 (7)
 ISH-positive/IHC 1+, 0 or unknown 5 (1) 2 (1) 3 (1)
 ISH-negative/IHC 3+ 7 (2) 5 (1) 7 (2)
 ISH-negative or unknown/IHC 2+ 0 0 2 (1)
 ISH unknown/IHC 3+ 32 (9) 30 (8) 29 (8)
HER3 mRNA
 n (%) 331 (91) 342 (93) 332 (91)
 Median (range) 1.88 (0.1–33.1) 1.57 (0.1–52.7) 1.71 (0.1–26.0)
PIK3CA status
 n (%) 326 (89) 332 (90) 328 (90)
 Mutated, n (%) 83 (25) 92 (28) 88 (27)
 Non-mutated, n (%) 243 (75) 240 (72) 240 (73)
PTEN H-score
 n (%) 182 (50) 181 (49) 179 (49)
 Median (range) 135.0 (0.0–310.0) 180.0 (0.0–370.0) 160.0 (0.0–380.0)
HER2 distribution
 n (%)b 360 (99) 365 (99) 360 (99)
 Focal (10–29%), n (%) 14 (4) 12 (3) 15 (4)
 Heterogeneous (30–79%), n (%) 35 (10) 37 (10) 33 (9)
 Homogeneous (≥80%), n (%) 311 (86) 316 (87) 312 (87)
  1. aIntention-to-treat population
  2. bOnly includes patients who were IHC 2+ or IHC 3 +
  3. Biomarker prevalence reported here is based on the number of patients with data available for each marker. HER2 human epidermal growth factor receptor 2, IHC immunohistochemistry, ISH in situ hybridization, PIK3CA phosphoinositide 3-kinase catalytic subunit alpha, P pertuzumab, PTEN phosphatase and tensin homolog, T-DM1 trastuzumab emtansine