[CGS20267 (Letrozole), a new aromatase inhibitor: late phase II study for postmenopausal women with advanced or recurrent breast cancer (no. 1)--investigation of recommended clinical dose CGS20267 Study Group].
To determine the recommended clinical dose of CGS20267 (Letrozole), we conducted a randomized comparative study as a late phase II study (first part) in postmenopausal women with advanced or recurrent breast cancer. Forty-one patients were randomly assigned to receive 0.5 mg or 1.0 mg once daily. There were no statistically significant differences in background between the two groups. Although there was no significant difference in the objective response rates between the two groups, the rate was higher at 1.0 mg (44.4%) than at 0.5 mg (38.1%). We also combined these data with the results of an early phase II study. The objective response rates (CR + PR) were 31.4% at 0.5 mg and 42.2% at 1.0 mg, and response rates consisting of CR, PR, and NC for longer than 6 months were significantly higher at a dose of 1.0 mg (68.9%) than 0.5 mg (41.2%). Side effects included drug-related adverse events in 36.8% at 0.5 mg and in 31.6% at 1.0 mg. All of the events were grade 2 or lower, indicating a favorable tolerability of CGS20267. These results demonstrated that CGS20267 1.0 mg once daily is more effective than 0.5 mg, and has comparable safety, in the treatment of postmenopausal women with advanced or recurrent breast cancer. We conclude the recommended clinical dose of CGS20267 should be 1.0 mg once daily.
Abe
Rikiya
R
Dept. of Surgery II, Fukushima Medical College.
Tominaga
Takeshi
T
Nomizu
Tadashi
T
Nomura
Yasuo
Y
Takashima
Shigemitsu
S
Koyama
Hiroki
H
Sano
Muneaki
M
Tohge
Tetsuya
T
Ueo
Hiroaki
H
Ikeda
Seiyo
S
Ohashi
Yasuo
Y
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D047072:Aromatase Inhibitors; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality; D004791:Enzyme Inhibitors / Q000008:administration & dosage*; D004967:Estrogens / Q000097:blood; D005260:Female; D006801:Humans; D000077289:Letrozole; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy*; D009570:Nitriles / Q000008:administration & dosage*; D017698:Postmenopause; D015996:Survival Rate; D014230:Triazoles / Q000008:administration & dosage*
D000970:Antineoplastic Agents; D047072:Aromatase Inhibitors; D004791:Enzyme Inhibitors; D004967:Estrogens; D009570:Nitriles; D014230:Triazoles; D000077289:Letrozole