Randomized study of Lapatinib alone or in combination with trastuzumab in women with ErbB2-positive, trastuzumab-refractory metastatic breast cancer.
OBJECTIVE
Preclinical studies in ErbB2-positive cell lines demonstrated a synergistic interaction between lapatinib and trastuzumab, suggesting that dual blockade is more effective than a single agent alone. EGF104900 compared the activity of lapatinib alone or in combination with trastuzumab in patients with ErbB2-positive, trastuzumab-refractory metastatic breast cancer (MBC).


METHODS
Patients with ErbB2-positive MBC who experienced progression on prior trastuzumab-containing regimens were randomly assigned to receive either lapatinib alone or in combination with trastuzumab. The primary end point was progression-free survival (PFS). Secondary efficacy end points included overall response rate (ORR), clinical benefit rate (CBR; complete response, partial response, and stable disease for >/= 24 weeks), and overall survival (OS).


RESULTS
In the intent-to-treat population (N = 296) who received a median of three prior trastuzumab-containing regimens, the combination of lapatinib with trastuzumab was superior to lapatinib alone for PFS (hazard ratio [HR] = 0.73; 95% CI, 0.57 to 0.93; P = .008) and CBR (24.7% in the combination arm v 12.4% in the monotherapy arm; P = .01). A trend for improved OS in the combination arm was observed (HR = 0.75; 95% CI, 0.53 to 1.07; P = .106). There was no difference in ORR (10.3% in the combination arm v 6.9% in the monotherapy arm; P = .46). The most frequent adverse events were diarrhea, rash, nausea, and fatigue; diarrhea was higher in the combination arm (P = .03). The incidence of symptomatic and asymptomatic cardiac events was low (combination therapy = 2% and 3.4%; monotherapy = 0.7% and 1.4%, respectively).


CONCLUSIONS
Despite disease progression on prior trastuzumab-based therapy, lapatinib in combination with trastuzumab significantly improved PFS and CBR versus lapatinib alone, thus offering a chemotherapy-free option with an acceptable safety profile to patients with ErbB2-positive MBC.
Blackwell
Kimberly L
KL
Duke University Medical Center, Durham, NC 27701, USA. black034@mc.duke.edu
Burstein
Harold J
HJ
Storniolo
Anna Maria
AM
Rugo
Hope
H
Sledge
George
G
Koehler
Maria
M
Ellis
Catherine
C
Casey
Michelle
M
Vukelja
Svetislava
S
Bischoff
Joachim
J
Baselga
Jose
J
O'Shaughnessy
Joyce
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000008:administration & dosage* / Q000009:adverse effects; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D000077341:Lapatinib; D008875:Middle Aged; D009362:Neoplasm Metastasis; D011788:Quality of Life; D011799:Quinazolines / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D013318:Stroke Volume / Q000187:drug effects; D000068878:Trastuzumab; D016277:Ventricular Function, Left / Q000187:drug effects
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D000077341:Lapatinib; D011799:Quinazolines; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human