Clinical benefit of fulvestrant in postmenopausal women with advanced breast cancer and primary or acquired resistance to aromatase inhibitors: final results of phase II Swiss Group for Clinical Cancer Research Trial (SAKK 21/00).
BACKGROUND
The aim of this study was to evaluate the efficacy and tolerability of fulvestrant, an estrogen receptor antagonist, in postmenopausal women with hormone-responsive tumors progressing after aromatase inhibitor (AI) treatment.


METHODS
This is a phase II, open, multicenter, noncomparative study. Two patient groups were prospectively considered: group A (n=70) with AI-responsive disease and group B (n=20) with AI-resistant disease. Fulvestrant 250 mg was administered as intramuscular injection every 28 (+/-3) days.


RESULTS
All patients were pretreated with AI and 84% also with tamoxifen or toremifene; 67% had bone metastases and 45% liver metastases. Fulvestrant administration was well tolerated and yielded a clinical benefit (CB; defined as objective response or stable disease [SD] for >or=24 weeks) in 28% (90% confidence interval [CI] 19% to 39%) of patients in group A and 37% (90% CI 19% to 58%) of patients in group B. Median time to progression (TTP) was 3.6 (95% CI 3.0 to 4.8) months in group A and 3.4 (95% CI 2.5 to 6.7) months in group B.


CONCLUSIONS
Overall, 30% of patients who had progressed following prior AI treatment gained CB with fulvestrant, thereby delaying indication to start chemotherapy. Prior response to an AI did not appear to be predictive for benefit with fulvestrant.
Perey
L
L
Swiss Group for Clinical Cancer Research (SAKK), Bern, Switzerland.
Paridaens
R
R
Department of General Medical Oncology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
Hawle
H
H
Swiss Group for Clinical Cancer Research (SAKK), Bern, Switzerland.
Zaman
K
K
Swiss Group for Clinical Cancer Research (SAKK), Bern, Switzerland. Electronic address: Khalil.Zaman@chuv.ch.
Nolé
F
F
Unit for Medical Care, Department of Medicine, European Institute of Oncology, Milan, Italy.
Wildiers
H
H
Department of General Medical Oncology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
Fiche
M
M
Swiss Group for Clinical Cancer Research (SAKK), Bern, Switzerland.
Dietrich
D
D
Swiss Group for Clinical Cancer Research (SAKK), Bern, Switzerland.
Clément
P
P
Department of General Medical Oncology, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
Köberle
D
D
Swiss Group for Clinical Cancer Research (SAKK), Bern, Switzerland.
Goldhirsch
A
A
Unit for Medical Care, Department of Medicine, European Institute of Oncology, Milan, Italy.
Thürlimann
B
B
Swiss Group for Clinical Cancer Research (SAKK), Bern, Switzerland.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D047072:Aromatase Inhibitors / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000556:secondary; D018450:Disease Progression; D019008:Drug Resistance, Neoplasm; D004958:Estradiol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D020847:Estrogen Receptor Modulators / Q000627:therapeutic use; D005260:Female; D000077267:Fulvestrant; D006801:Humans; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000473:pathology; D017698:Postmenopause; D011960:Receptors, Estrogen / Q000378:metabolism; D016879:Salvage Therapy; D016896:Treatment Outcome
D018931:Antineoplastic Agents, Hormonal; D047072:Aromatase Inhibitors; D020847:Estrogen Receptor Modulators; D011960:Receptors, Estrogen; D000077267:Fulvestrant; D004958:Estradiol