Class/mechanism: Selective non-steroidal aromatase inhibitor. The aromatase enzyme converts adrenal and ovarian androgens (androstenedione and testosterone) to estrogens (estrone and estradiol) in peripheral tissues. Letrozole competitively binds to and inhibits the aromatase by binding to the heme of the enzyme's cytochrome P450.
For conciseness and simplicity, HemOnc.org currently will focus on treatment regimens and not list information such as: renal/hepatic dose adjustments, metabolism (including CYP450), excretion, monitoring parameters (although this will be considered for checklists), or manufacturer. Instead, for the most current information, please refer to your preferred pharmacopeias such as Micromedex, Lexicomp, UpToDate (courtesy of Lexicomp), or the prescribing information.
Diseases for which it is used
Patient drug information
- Letrozole (Femara) package insert
- Letrozole (Femara) patient drug information (Chemocare)
- Letrozole (Femara) patient drug information (UpToDate)
History of changes in FDA indication
- 7/25/1997: Initial approval for the treatment of advanced breast cancer in postmenopausal women
- 10/29/2004: Label expanded for the extended adjuvant treatment of early breast cancer in postmenopausal women who have received 5 years of adjuvant tamoxifen therapy. (Indication expanded to adjuvant setting after prior therapy)
- 12/28/2005: Label expanded for the adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer. (Indication expanded to adjuvant setting)
- 3/2/2010: Label simplified to adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer. (No change)
- 3/2/2010: Label simplified to extended adjuvant treatment of postmenopausal women with early breast cancer who have received prior standard adjuvant tamoxifen therapy. (Years requirement removed)
- 3/2/2010: Label simplified to first and second-line treatment of postmenopausal women with hormone receptor positive or unknown advanced breast cancer.
Also known as
- Code name: CGS 20267
- Brand names: Femara, Fempro, Gynotril, Latrotal, Lerozol, Letoval, Letpro, Letromina, Letroplex, Letroz, Letrozol, Lexel, Lezole