Formestane, a steroidal aromatase inhibitor after failure of non-steroidal aromatase inhibitors (anastrozole and letrozole): is a clinical benefit still achievable?
BACKGROUND
There are few clinical data on the sequential use of aromatase inhibitors (AI). This paper focuses on the relevance of clinical benefit CB (CR + PR + SD > or = 6 months) in postmenopausal metastatic breast cancer (MBC) patients treated with the steroidal aromatase inhibitor (SAI) formestane (FOR). who had already received non-steroidal aromatase inhibitor (nSAI): letrozole (LTZ) or anastrozole (ANZ).


METHODS
Twenty postmenopausal women with MBC were analysed in this retrospective two-centre study with the sequence nSAI-FOR. When receiving ANZ, 1 of 11 achieved a complete response and 9 of 11 a stable disease > or = 6 months, and receiving LTZ 1 of 9 achieved a partial response and 4 of 9 a stable disease > or = 6 months. The analysis of the entire population treated with FOR showed an overall CB of 55% (11 of 20) with a median duration of 15 months and median time to progression (TTP) of 6 months.


CONCLUSIONS
Formestane 250 mg once bi-weekly seems to be an attractive alternative third-line hormonal therapy for the treatment of patients with MBC, previously treated with nSAI.
Carlini
P
P
Department of Medical Oncology, Regina Elena National Cancer Institute, Rome, Italy. pcarlini@iol.it
Frassoldati
A
A
De Marco
S
S
Casali
A
A
Ruggeri
E M
EM
Nardi
M
M
Papaldo
P
P
Fabi
A
A
Paoloni
F
F
Cognetti
F
F
D000328:Adult; D000368:Aged; D000077384:Anastrozole; D000735:Androstenedione / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D047072:Aromatase Inhibitors; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D002986:Clinical Trials as Topic; D018450:Disease Progression; D004791:Enzyme Inhibitors / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D000077289:Letrozole; D008875:Middle Aged; D009570:Nitriles / Q000627:therapeutic use; D017698:Postmenopause; D011960:Receptors, Estrogen / Q000032:analysis; D012189:Retrospective Studies; D017211:Treatment Failure; D014230:Triazoles / Q000627:therapeutic use
D000970:Antineoplastic Agents; D047072:Aromatase Inhibitors; D004791:Enzyme Inhibitors; D009570:Nitriles; D011960:Receptors, Estrogen; D014230:Triazoles; D000077384:Anastrozole; D000735:Androstenedione; D000077289:Letrozole; C014594:formestane