Trastuzumab single-drug therapy after failure of cytotoxic treatment for metastatic breast cancer.
BACKGROUND
Trastuzumab is an established component of breast cancer combination regimens, but data on the safety and efficacy of single-agent therapy is sparse.


METHODS
70 Patients with HER2-overexpressing breast cancer after failure of at least one chemotherapy regimen for metastatic disease were recruited from 28 institutions. HER2 overexpression was 3+ in 96% and 2+/FISH+ in 4%. Treatment consisted of a loading dose of 4 mg/kg trastuzumab in the first week and 2 mg/kg per week thereafter, continued until progression.


RESULTS
Trastuzumab treatment duration ranged from 1 to 66 weeks (median: 12). Objective responses (complete response (CR)/partial response (PR)) were seen in 12/62 fully evaluable patients (19%; 2 CR) while another 29% showed stabilization of the disease. Half of the patients had experienced progression after 13 weeks while median duration of response reached 44 weeks. Median survival was 68 weeks with nearly one-third of the patients still alive after more than 3 years. The most frequent adverse reaction was infusion-related syndrome arising during the first administration. Significant cardiovascular problems were detected in 3 cases, all with anthracycline pretreatment.


CONCLUSIONS
Patients with metastatic breast cancer overexpressing HER2 may benefit from trastuzumab single-drug treatment, predominantly due to its favourable safety profile.
Clemens
Michael
M
Klinikum Mutterhaus der Borromäerinnen gGmbH, Trier, Germany.
Eidtmann
Holger
H
Nitz
Ulrike
U
Niederle
Norbert
N
du Bois
Andreas
A
Grischke
Eva-Maria
EM
Hinke
Axel
A
von Minckwitz
Gunter
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000556:secondary*; D002277:Carcinoma / Q000188:drug therapy* / Q000378:metabolism / Q000556:secondary*; D005260:Female; D005858:Germany; D006801:Humans; D008875:Middle Aged; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D000068878:Trastuzumab; D016896:Treatment Outcome; D055815:Young Adult
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human