TY - JOUR
T1 - Sequential treatment with exemestane and non-steroidal aromatase inhibitors in advanced breast cancer
AU - Bertelli, Gianfilippo
AU - Garrone, Ornella
AU - Merlano, Marco
AU - Occelli, Marcella
AU - Bertolotti, Laura
AU - Castiglione, Federico
AU - Pepi, Fiorella
AU - Fusco, Ornella
AU - Del Mastro, Lucia
AU - Leonard, Robert C F
PY - 2006/1
Y1 - 2006/1
N2 - Background: The steroidal aromatase inactivator exemestane has demonstrated activity after prior failure of non-steroidal aromatase inhibitors (including third-generation inhibitors letrozole and anastrozole) in post-menopausal women with advanced breast cancer. If exemestane is used as first anti-aromatase agent, however, it is unclear whether patients can still benefit from letrozole or anastrozole after progression. Patients and Methods: Postmenopausal patients with advanced, hormone receptor-positive or -unknown breast cancer were eligible for this study. Patients with no prior exposure to anti-aromatase drugs received exemestane, 25 mg daily, as first anti-aromatase agent. At the time of progression, patients were crossed-over to anastrozole or letrozole if further endocrine therapy was considered appropriate. Patients with prior exposure to anti-aromatase agents were also included in the study, and were given anastrozole or letrozole if they had previously received exemestane, or exemestane if they had previously received anastrozole or letrozole. The primary endpoint of the study was the clinical benefit rate (complete response + partial response + stabilization of disease for ≥24 weeks). Results: Forty patients received exemestane 25 mg daily as first anti-aromatase agent, with a CB rate of 67.5% (95% CI 52.9-82.0%) and a median time to progression (TTP) of 9.6 months. In 18 patients, letrozole (n = 17) or anastrozole (n = 1) were used after failure of exemestane: the CB rate was 55.6% (95% CI 32.6-78.5%) with a median TTP of 9.3 months. In 23 patients, exemestane was used after failure of letrozole or anastrozole: the CB rate was 43.5% (95% CI 23.2-63.7%) with a median TTP of 5.1 months. Conclusions: Our study confirms that exemestane is active after prior failure of letrozole or anastrozole. We have also shown that patients can receive exemestane as their first anti-aromatase agent and still benefit from letrozole or anastrozole after progression. This suggests that the partial non-cross resistance between steroidal and non-steroidal anti-aromatase agents is independent of the sequence employed.
AB - Background: The steroidal aromatase inactivator exemestane has demonstrated activity after prior failure of non-steroidal aromatase inhibitors (including third-generation inhibitors letrozole and anastrozole) in post-menopausal women with advanced breast cancer. If exemestane is used as first anti-aromatase agent, however, it is unclear whether patients can still benefit from letrozole or anastrozole after progression. Patients and Methods: Postmenopausal patients with advanced, hormone receptor-positive or -unknown breast cancer were eligible for this study. Patients with no prior exposure to anti-aromatase drugs received exemestane, 25 mg daily, as first anti-aromatase agent. At the time of progression, patients were crossed-over to anastrozole or letrozole if further endocrine therapy was considered appropriate. Patients with prior exposure to anti-aromatase agents were also included in the study, and were given anastrozole or letrozole if they had previously received exemestane, or exemestane if they had previously received anastrozole or letrozole. The primary endpoint of the study was the clinical benefit rate (complete response + partial response + stabilization of disease for ≥24 weeks). Results: Forty patients received exemestane 25 mg daily as first anti-aromatase agent, with a CB rate of 67.5% (95% CI 52.9-82.0%) and a median time to progression (TTP) of 9.6 months. In 18 patients, letrozole (n = 17) or anastrozole (n = 1) were used after failure of exemestane: the CB rate was 55.6% (95% CI 32.6-78.5%) with a median TTP of 9.3 months. In 23 patients, exemestane was used after failure of letrozole or anastrozole: the CB rate was 43.5% (95% CI 23.2-63.7%) with a median TTP of 5.1 months. Conclusions: Our study confirms that exemestane is active after prior failure of letrozole or anastrozole. We have also shown that patients can receive exemestane as their first anti-aromatase agent and still benefit from letrozole or anastrozole after progression. This suggests that the partial non-cross resistance between steroidal and non-steroidal anti-aromatase agents is independent of the sequence employed.
KW - Anastrozole
KW - Aromatase inhibitors
KW - Breast cancer, endocrine therapy
KW - Exemestane
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UR - http://www.scopus.com/inward/citedby.url?scp=32044460822&partnerID=8YFLogxK
U2 - 10.1159/000090985
DO - 10.1159/000090985
M3 - Article
C2 - 16410685
AN - SCOPUS:32044460822
VL - 69
SP - 471
EP - 477
JO - Oncology
JF - Oncology
SN - 0030-2414
IS - 6
ER -