[A dose-comparative study on TAP-144-SR, an LH-RH agonist depot formulation, in premenopausal patients with advanced or recurrent breast cancer. TAP-144-SR Breast Cancer Study Group].

A comparative phase II study was performed with different doses of TAP-144-SR in ER-positive or ER-unknown premenopausal patients with advanced or recurrent breast cancer. One hundred and six patients were randomly allocated to either 3.75 mg or 7.5 mg treatment by a centralized telephone registration system. TAP-144-SR was administered sc at 4-week intervals for 12 weeks (a total of 3 injections). Ninety-five cases were evaluated with the response rate of 30.4% (14/46) in the 3.75 mg group and 24.5% (12/49) in the 7.5 mg group, respectively. Serum estradiol was decreased to postmenopausal level (< 30 pg/ml) within 3-4 weeks after the first dose in the both dose groups, and this suppression was maintained throughout the treatment period. The adverse reactions most frequently observed were climacteric disturbances like hot flashes which was likely to be due to the hypoestrogen status. In conclusion, there was no significant difference between both dose groups in terms of response rates, adverse effects, and hormonal suppression. Therefore, the lower dose is recommended for the further study.