FEMARA

What it is

Femara is a medicine containing letrozole 2.5 mg as coated tablets. Letrozole is a non-steroidal aromatase inhibitor used as an antineoplastic agent. It inhibits the aromatase enzyme by competitively binding to the haem of the cytochrome P450 subunit of the enzyme, resulting in a reduction of oestrogen biosynthesis in all tissues.

Approved indications

— Treatment of postmenopausal women with hormone receptor positive breast cancer.

Dosing overview

The recommended dose of Femara is one 2.5 mg tablet daily. In the adjuvant setting, treatment should continue for 5 years or until tumour relapse occurs, whichever comes first. In patients with metastatic disease, treatment with Femara should continue until tumour progression is evident.

Key safety warnings

Osteoporosis and bone fractures have been reported with the use of Femara, and monitoring of overall bone health is recommended during treatment. Tendonitis and tenosynovitis have been associated with Femara and aromatase inhibitors, with tendon rupture identified as a potential risk, though tendonitis and tenosynovitis are of uncommon occurrence and tendon rupture of rare occurrence. Patients should be monitored for signs and symptoms of tendon disorders during treatment with Femara. In patients with severe hepatic cirrhosis, systemic exposure and terminal half-life were approximately doubled compared to healthy volunteers. Patients with severe hepatic impairment should be kept under close supervision.

Contraindications

Femara is contraindicated in cases of hypersensitivity to the active substance or to any of the excipients, premenopausal endocrine status, pregnancy, and lactation.

PBS listing

Femara 2.5 mg tablets are listed on the PBS with 2 items. The listing is restricted, with an ex-manufacturer price of A$14.53.

Regulatory history

Femara letrozole 2.5 mg tablets were first registered on the ARTG on 30 October 1997. The BIG 1-98 study was a multi-centre, double-blind, randomised study conducted in over 8000 postmenopausal women with resected receptor-positive early breast cancer, investigating whether Femara for 5 years was superior to tamoxifen for 5 years and whether switching endocrine treatments at 2 years was superior to continuing the same agent. Femara for 5 years was superior to tamoxifen for efficacy endpoints of disease free survival, time to distant metastases, and systemic disease free survival.