CLINICAL EFFICACY AND ENDOCRINE ACTIVITY OF VOROZOLE IN POSTMENOPAUSAL BREAST-CANCER PATIENTS - RESULTS OF A MULTICENTRIC PHASE-II STUDY

Background. Aminoglutethimide was the first aromatase inhibitor to be used successfully in breast cancer patients. However, this drug also i nhibits mineral corticoid and glucocortioid synthesis, making co-medic ation with corticosteroids necessary, and it is often poorly tolerated . The primary objective of this trial was to evaluate the clinical eff icacy and tolerability of vorozole, a new non-steroidal oral aromatase inhibitor, in postmenopausal breast cancer patients. The secondary ob jective was to evaluate the pharmacodynamic activity of the drug. Subj ects and method's. Thirty-four postmenopausal patients previously trea ted with tamoxifen in the adjuvant setting and/or for advanced disease were treated with vorozole, 2.5 mg once daily. Patients were monitore d with respect to treatment efficacy and safety. Hormonal evaluations were performed at baseline and during the course of treatment in order to evaluate the pharmacodynamic efficacy and safety of vorozole. Resu lts: According to UICC criteria, there were seven responders, one comp lete and six partial, for an overall response rate of 21% (95% confide nce interval (CI) 9%-38%). The median duration of response was 9.6 mon ths (95% CI 4.6-0), the median time to progression for the entire grou p was 4.7 months (95% CI 2.9-6.6) and the median survival time was 29. 7 months (95% CI 19.1-0). Tolerability was excellent to good in 97% of the patients. Oestradiol and oestrone levels were suppressed to the l imit of detection of the assays used. No effect was observed on the ot her endocrine parameters. Conclusions. Our results suggest that vorozo le is an effective and safe drug for the treatment of advanced postmen opausal breast cancer following tamoxifen failure.