Phase II trial of weekly vinorelbine and trastuzumab as first-line therapy in patients with HER2(+) metastatic breast cancer.
OBJECTIVE
Human epidermal growth factor receptor 2 (HER2) overexpression is associated with a more aggressive form of breast cancer that responds well to trastuzumab therapy. Trastuzumab-based combination regimens have shown greater antitumor activity than chemotherapy alone. These findings, coupled with the favorable antitumor activity and tolerability profile of vinorelbine in breast cancer, provided the rationale for investigating the novel combination of vinorelbine and trastuzumab.


METHODS
A phase II, open-label trial of intravenous vinorelbine (30 mg/m(2) on day 1, then weekly) and trastuzumab (4 mg/kg on day 0, then 2 mg/kg weekly) was conducted in previously untreated HER2(+) metastatic breast cancer patients. Vinorelbine dose was adjusted for grade 3/4 neutropenia; patients remained on combination therapy until disease progression or patient withdrawal due to adverse events.


RESULTS
Of 40 enrolled patients (median age 51 years, range 30-82), 37 were evaluable for response. Overall response rate was 78% (29/37, 95% confidence interval [CI] 62%-90%), including four (11%, 95% CI 3%-25%) complete and 25 (68%) partial responses. Objective tumor response correlated with degree of HER2 positivity: immunohistochemistry (IHC) 3(+) = 82% (18/22) response and IHC 2(+) = 58% (7/12) response. Median time to progression was 72 weeks (95% CI 37-138 weeks); median survival has not been reached. Grade 3/4 neutropenia was the most frequent serious toxicity and cause of dose reductions (9% of courses) and omissions (10% of courses). No patient experienced serious cardiac toxicity.


CONCLUSIONS
Weekly vinorelbine/trastuzumab offers a high therapeutic index as initial therapy in patients with HER2(+) metastatic breast cancer. Further investigation of this novel regimen is planned.
Jahanzeb
Mohammad
M
The Boca Raton Comprehensive Cancer Center, Florida, USA. mjahanze@utmem.edu
Mortimer
Joanne E
JE
Yunus
Furhan
F
Irwin
David H
DH
Speyer
James
J
Koletsky
Alan J
AJ
Klein
Paula
P
Sabir
Tariq
T
Kronish
Lori
L
D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D061067:Antibodies, Monoclonal, Humanized; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008875:Middle Aged; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics*; D015996:Survival Rate; D000068878:Trastuzumab; D016896:Treatment Outcome; D014747:Vinblastine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000077235:Vinorelbine
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; D014747:Vinblastine; D000077235:Vinorelbine