Use of chemotherapy plus a monoclonal antibody against HER2 for metastatic breast cancer that overexpresses HER2.
BACKGROUND
The HER2 gene, which encodes the growth factor receptor HER2, is amplified and HER2 is overexpressed in 25 to 30 percent of breast cancers, increasing the aggressiveness of the tumor.


METHODS
We evaluated the efficacy and safety of trastuzumab, a recombinant monoclonal antibody against HER2, in women with metastatic breast cancer that overexpressed HER2. We randomly assigned 234 patients to receive standard chemotherapy alone and 235 patients to receive standard chemotherapy plus trastuzumab. Patients who had not previously received adjuvant (postoperative) therapy with an anthracycline were treated with doxorubicin (or epirubicin in the case of 36 women) and cyclophosphamide alone (138 women) or with trastuzumab (143 women). Patients who had previously received adjuvant anthracycline were treated with paclitaxel alone (96 women) or paclitaxel with trastuzumab (92 women).


RESULTS
The addition of trastuzumab to chemotherapy was associated with a longer time to disease progression (median, 7.4 vs. 4.6 months; P<0.001), a higher rate of objective response (50 percent vs. 32 percent, P<0.001), a longer duration of response (median, 9.1 vs. 6.1 months; P<0.001), a lower rate of death at 1 year (22 percent vs. 33 percent, P=0.008), longer survival (median survival, 25.1 vs. 20.3 months; P=0.01), and a 20 percent reduction in the risk of death. The most important adverse event was cardiac dysfunction of New York Heart Association class III or IV, which occurred in 27 percent of the group given an anthracycline, cyclophosphamide, and trastuzumab; 8 percent of the group given an anthracycline and cyclophosphamide alone; 13 percent of the group given paclitaxel and trastuzumab; and 1 percent of the group given paclitaxel alone. Although the cardiotoxicity was potentially severe and, in some cases, life-threatening, the symptoms generally improved with standard medical management.


CONCLUSIONS
Trastuzumab increases the clinical benefit of first-line chemotherapy in metastatic breast cancer that overexpresses HER2.
Division of Hematology and Oncology, UCLA School of Medicine, Los Angeles, Calif 90095-1678, USA. dslamon@mednet.ucla.edu
D J
DJ
Slamon
B
B
Leyland-Jones
S
S
Shak
H
H
Fuchs
V
V
Paton
A
A
Bajamonde
T
T
Fleming
W
W
Eiermann
J
J
Wolter
M
M
Pegram
J
J
Baselga
L
L
Norton
D000328:Adult; D000368:Aged; D018943:Anthracyclines / Q000009:adverse effects / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000009:adverse effects / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D003520:Cyclophosphamide / Q000009:adverse effects / Q000627:therapeutic use; D018450:Disease Progression; D004317:Doxorubicin / Q000009:adverse effects / Q000627:therapeutic use; D015251:Epirubicin / Q000627:therapeutic use; D005260:Female; D006331:Heart Diseases / Q000139:chemically induced; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D017239:Paclitaxel / Q000009:adverse effects / Q000627:therapeutic use; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology* / Q000378:metabolism; D016019:Survival Analysis; D000068878:Trastuzumab
D018943:Anthracyclines; D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D003520:Cyclophosphamide; D004317:Doxorubicin; D015251:Epirubicin; D017239:Paclitaxel; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab