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Poster display session

3538 - Long-term responders to trastuzumab monotherapy in the first-line metastatic setting: characteristics and survival data (SAKK 22/99 Trial)


11 Sep 2017


Poster display session


Cytotoxic Therapy;  Breast Cancer


Sabine Schmid


Annals of Oncology (2017) 28 (suppl_5): v74-v108. 10.1093/annonc/mdx365


S. Schmid1, D. Klingbiel2, A. Goldhirsch3, C. Oehlschlegel4, E. Munzone5, F. Nolè3, B. Pestalozzi6, S. Aebi7, C. Rochlitz8, R. von Moos9, K. Zaman10, C. Mamot11, P. Weder1, B. Thuerlimann1, O. Pagani12, T. Ruhstaller1

Author affiliations

  • 1 Breast Center St. Gallen, Kantonsspital St. Gallen, 9007 - St. Gallen/CH
  • 2 Coordinating Center, SAKK, 3000 - berne/CH
  • 3 Department Of Oncology, Istituto Europeo di Oncologia, 20141 - Milan/IT
  • 4 Institute Of Pathology, Kantonsspital St. Gallen, 9007 - St. Gallen/CH
  • 5 5. division Of Medical Senology, European Institute of Oncology (IEO), 20133 - Milan/IT
  • 6 Department Of Oncology, Universitätsspital Zürich, 8091 - Zürich/CH
  • 7 Department Of Oncology, Inselspital, University Hospital Bern, Bern/CH
  • 8 Department Of Oncology, University Hospital Basel, 4031 - Basel/CH
  • 9 Department Of Oncology, Kantonsspital Graubünden, 8000 - Chur/CH
  • 10 Department Of Oncology, Centre Hospitalier Universitaire Vaudois - CHUV, 1011 - Lausanne/CH
  • 11 Department Of Oncology, Kantonsspital Aarau, Aarau/CH
  • 12 Iosi, Ospedale Regionale Bellinzona e Valli, Bellinzona/CH


Abstract 3538


The prospective randomized trial SAKK 22/99 compared first-line trastuzumab plus chemotherapy with the sequential use of trastuzumab followed by chemotherapy plus trastuzumab at progression in patients with stage 4 HER2-positive breast cancer. The main results were recently published in Annals of Oncology. Here we report characteristics and outcomes of patients with long-lasting disease control with trastuzumab alone.


Long-term responders to trastuzumab monotherapy were defined as patients achieving disease control for ≥ 6 months. A risk score was defined as sum of negative prognostic factors (NPFs): ER negative (neg), PgR neg and visceral disease. The HER2:CEP17 FISH ratio was correlated with duration of response. Standard descriptive statistics were used. Survival analysis was done using the Kaplan-Meier method.


Of 175 enrolled pts, 86 were randomised to receive trastuzumab monotherapy until PD. 24 patients (28%) were long-term responders (≥6 months). In a landmark analysis excluding patients who died within 6 months, 5y-overall survival (OS) in long-term responders was 54% (95% CI 31–72) compared to 18% (95% CI 10–30) in short-term responders (log-rank p = 0.02). Baseline characteristics were well-balanced except for visceral disease (see Table, Fisher’s exact test p = 0.01). With each additional NPF the proportion of long-term responders decreased: 0 NPF, 42%; 1 NPF, 40%; 2 NPFs, 35%; 3 NPFs 17%. Median FISH ratio was 4.8 (IQR 4.1–5.3) in long-term responders and 4.7 (IQR 2.5–5.3) in short-term responders; no long-term responders were in the lowest quartile of all FISH ratios.Table:

300P Baseline characteristics

HER2-long Responders (N = 24)HER2-short Responders (N = 62)
Age (med)57 years52 years
Visceral disease (yes)46%76%
ER-Status (pos)59%60%
PR-Status (pos)48%41%
FISH (med. Ratio)4.84.7
ALP U/l (med)74103
Hb g/l (med)130134
WBC G/l (med)5.86.8
Endocrine treatment adj (yes)33%48%


Long response to trastuzumab monotherapy is prognostic with significantly higher 5y-survival rates in this cohort. Negative prognostic factors including lower FISH ratio may reduce the chance for long-term response to trastuzumab monotherapy as first line therapy.

Clinical trial identification

Subanalysis of SAKK 22/99 trial; NCT00004935

Legal entity responsible for the study

Swiss Group of Clinical Cancer Research (SAKK)




All authors have declared no conflicts of interest.

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