The evidence supporting this protocol is provided by a phase III, multicentre, international, randomised trial involving 907 patients comparing letrozole with tamoxifen alone as first-line therapy for advanced breast cancer in postmenopausal women.r
Between November 1996 and January 1999, 453 patients were randomised to receive letrozole 2.5 mg daily and 454 patients were randomised to receive tamoxifen 20 mg daily.r
The primary efficacy endpoint was time to progression (TTP) and secondary end points were overall objective tumour response rate (ORR), duration of overall response, rate of clinical benefit, duration of clinical benefit, time to treatment failure (TTF), time to response (TTR), number of deaths, overall survival (OS) and tolerability.r
Efficacy
TTP was significantly longer for letrozole than for tamoxifen (41 vs 26 weeks). Treatment with letrozole reduced the risk of progression by 30% (HR, 0.70; 95% confidence interval, 0.60 to 0.82, P = 0.0001). TTP was significantly longer for letrozole irrespective of dominant site of disease, receptor status, or prior adjuvant antiestrogen therapy.r
TTF was significantly longer for letrozole (40 vs 25 weeks). ORR was higher for letrozole (30% vs 20%; P =0.0006), as was the rate of clinical benefit (49% vs 38%; P =0.001).
Kaplan-Meier plot of time to progression (TTP) r
© Journal of Clinical Oncology 2001
Toxicity
Both treatments were well tolerated.
Adverse events1
© Journal of Clinical Oncology 2001