Results of the CONFIRM phase III trial comparing fulvestrant 250 mg with fulvestrant 500 mg in postmenopausal women with estrogen receptor-positive advanced breast cancer.
OBJECTIVE
We compared fulvestrant 500 mg regimen with the approved dose of fulvestrant 250 mg per month for treatment of postmenopausal women with estrogen receptor-positive advanced breast cancer who experienced progression after prior endocrine therapy.


METHODS
Comparison of Faslodex in Recurrent or Metastatic Breast Cancer (CONFIRM) is a double-blind, parallel-group, multicenter, phase III study. Patients were randomly assigned to fulvestrant 500 mg (500 mg intramuscularly [IM] on day 0, then 500 mg IM on days 14 and 28 and every 28 days thereafter) or 250 mg every 28 days. Primary end point was progression-free survival (PFS). Secondary end points included objective response rate, clinical benefit rate (CBR), duration of clinical benefit (DoCB), overall survival (OS), and quality of life (QOL).


RESULTS
PFS was significantly longer for fulvestrant 500 mg (n = 362) than 250 mg (n = 374) (hazard ratio [HR] = 0.80; 95% CI, 0.68 to 0.94; P = .006), corresponding to a 20% reduction in risk of progression. Objective response rate was similar for fulvestrant 500 mg and 250 mg (9.1% v 10.2%, respectively). CBR was 45.6% for fulvestrant 500 mg and 39.6% for fulvestrant 250 mg. DoCB and OS were 16.6 and 25.1 months, respectively, for the 500-mg group, whereas DoCB and OS were 13.9 and 22.8 months, respectively, in the 250-mg group. Fulvestrant 500 mg was well tolerated with no dose-dependent adverse events. QOL was similar for both arms.


CONCLUSIONS
Fulvestrant 500 mg was associated with a statistically significant increase in PFS and not associated with increased toxicity, corresponding to a clinically meaningful improvement in benefit versus risk compared with fulvestrant 250 mg.
Di Leo
Angelo
A
Sandro Pitigliani Medical Oncology Unit, Hospital of Prato, Prato, Italy. adileo@usl4.toscana.it
Jerusalem
Guy
G
Petruzelka
Lubos
L
Torres
Roberto
R
Bondarenko
Igor N
IN
Khasanov
Rustem
R
Verhoeven
Didier
D
Pedrini
José L
JL
Smirnova
Iya
I
Lichinitser
Mikhail R
MR
Pendergrass
Kelly
K
Garnett
Sally
S
Lindemann
Justin P O
JP
Sapunar
Francisco
F
Martin
Miguel
M
D018931:Antineoplastic Agents, Hormonal / Q000008:administration & dosage* / Q000009:adverse effects; D001938:Brazil; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004958:Estradiol / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D004965:Estrogen Antagonists / Q000008:administration & dosage* / Q000009:adverse effects; D005060:Europe; D005260:Female; D000077267:Fulvestrant; D006801:Humans; D007273:Injections, Intramuscular; D053208:Kaplan-Meier Estimate; D016015:Logistic Models; D008875:Middle Aged; D016017:Odds Ratio; D017698:Postmenopause; D016016:Proportional Hazards Models; D011788:Quality of Life; D011960:Receptors, Estrogen / Q000032:analysis / Q000037:antagonists & inhibitors*; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States
D018931:Antineoplastic Agents, Hormonal; D004965:Estrogen Antagonists; D011960:Receptors, Estrogen; D000077267:Fulvestrant; D004958:Estradiol