Activity of exemestane in metastatic breast cancer after failure of nonsteroidal aromatase inhibitors: a phase II trial.
OBJECTIVE
To evaluate the antitumor activity and toxicity of a new steroidal aromatase inactivator, exemestane, in postmenopausal women with metastatic breast cancer who had progressive disease (PD) after treatment with a nonsteroidal aromatase inhibitor.


METHODS
In this phase II trial, eligible patients were treated with exemestane 25 mg daily (n = 241) followed, at the time PD was determined, by exemestane 100 mg daily (n = 58).


RESULTS
On the basis of the intent-to-treat analysis by independent review, exemestane 25 mg produced objective responses in 6.6% of patients (95% confidence interval [CI], 3.8% to 10.6%) and overall success (complete response + partial response + no change for 24 weeks or longer) in 24.3% (95% CI, 19.0% to 30.2%). The median durations of objective response and overall success were 58.4 weeks (95% CI, 49.7 to 71.1 weeks) and 37.0 weeks (95% CI, 35.0 to 39.4 weeks), respectively. Increasing the dose of exemestane to 100 mg upon the development of PD produced one partial response (1.7%; 95% CI, 0.0% to 9.2%). Both dosages were well tolerated and were discontinued because of adverse events in only 1.7% of patients.


CONCLUSIONS
Exemestane 25 mg once daily seems to be an attractive alternative to chemotherapy for the treatment of patients with metastatic breast cancer after multiple hormonal therapies have failed.
Lønning
P E
PE
Department of Oncology, Haukeland University Hospital, Bergen, Norway. plon@haukeland.no
Bajetta
E
E
Murray
R
R
Tubiana-Hulin
M
M
Eisenberg
P D
PD
Mickiewicz
E
E
Celio
L
L
Pitt
P
P
Mita
M
M
Aaronson
N K
NK
Fowst
C
C
Arkhipov
A
A
di Salle
E
E
Polli
A
A
Massimini
G
G
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000730:Androstadienes / Q000008:administration & dosage / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000556:secondary*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D010166:Palliative Care; D017698:Postmenopause; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D016896:Treatment Outcome
D000730:Androstadienes; D000970:Antineoplastic Agents; D018931:Antineoplastic Agents, Hormonal; C056516:exemestane