Letrozole : in postmenopausal hormone-responsive early-stage breast cancer.
Letrozole is a highly selective, nonsteroidal, third-generation aromatase inhibitor approved for first-line and extended adjuvant therapy in postmenopausal women with hormone-responsive, early-stage breast cancer. Binding of letrozole to the haeme component of the cytochrome P450 subunit of aromatase inhibits estrogen biosynthesis throughout the body. As first-line adjuvant therapy in approximate, equals 8000 postmenopausal women with hormone-responsive, early-stage breast cancer, once-daily letrozole 2.5mg significantly prolonged disease-free survival (DFS; primary endpoint) and reduced the risk of relapse at distant sites relative to once-daily tamoxifen 20mg in the ongoing Breast International Group 1-98, double-blind, multinational trial. The median duration of follow-up for this primary core analysis was 25.8 months. Extended adjuvant therapy with once-daily letrozole 2.5mg significantly prolonged DFS relative to placebo treatment at a median follow-up of 30 months (primary endpoint) in the MA-17 trial in approximate, equals 5000 postmenopausal women who were disease free after 4.5-6 years of tamoxifen therapy for hormone-responsive, early-stage breast cancer. Letrozole treatment for up to 5 years was generally well tolerated in this clinical setting. As first-line treatment, relative to tamoxifen, letrozole was associated with a significantly lower incidence of venous thromboembolitic events, vaginal bleeding, hot flushes and night sweating, whereas the incidence of cardiac failure, bone fractures and arthralgia was higher in letrozole recipients.
Scott
Lesley J
LJ
Adis International Limited, Auckland, New Zealand. demail@adis.co.nz
Keam
Susan J
SJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D047072:Aromatase Inhibitors / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D006801:Humans; D000077289:Letrozole; D008297:Male; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D009570:Nitriles / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D017698:Postmenopause; D016032:Randomized Controlled Trials as Topic; D020845:Selective Estrogen Receptor Modulators / Q000009:adverse effects / Q000627:therapeutic use; D013629:Tamoxifen / Q000009:adverse effects / Q000627:therapeutic use; D013923:Thromboembolism / Q000209:etiology; D014230:Triazoles / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use*; D020246:Venous Thrombosis / Q000209:etiology
D000970:Antineoplastic Agents; D047072:Aromatase Inhibitors; D009570:Nitriles; D020845:Selective Estrogen Receptor Modulators; D014230:Triazoles; D013629:Tamoxifen; D000077289:Letrozole