VOROZOLE (RIVIZOR(TM)) - AN ACTIVE AND WELL TOLERATED NEW AROMATASE INHIBITOR FOR THE TREATMENT OF ADVANCED BREAST-CANCER PATIENTS WITH PRIOR TAMOXIFEN EXPOSURE

Vorozole (Rivizor(TM)) is a potent and stereospecific inhibitor of aro matase having shown promising endocrine effects in phase I studies. In the present trial, 27 postmenopausal patients with advanced breast ca ncer, measurable lesions, presumably hormone responsive (ER or PR+, or ER? with disease-free survival longer than 1 year, or prior documente d response to tamoxifen), were treated with vorozole one tablet 2.5 mg daily. All had been previously treated with tamoxifen as adjuvant (tw o patients) or for advanced disease (24 patients), or both (one patien t). Objective remissions were observed in eight patients (30%) with tw o complete responses (CR) and six partial responses (PR) lasting for a median of 14.3 months (range 6.8-40.6); nine stabilizations were also recorded (median 7.9 months; range 3.7-40.1). Median time to progress ion for the 27 patients was 5.9 months. Sites of response were skin (t hree patients), lymph nodes (two patients), lung (two patients) and ch est wall plus lymph nodes (one patient). Treatment was very well toler ated: mild hot flushes (four patients), gastrointestinal complaints (f our patients) and no significant toxicity (common toxicity criteria gr ade above 2) or drug-related severe adverse event. It is concluded tha t vorozole is an active second-line endocrine treatment, deserving con sideration for randomized comparison with other agents such as aminogl utethimide, megestrol acetate or medroxyprogesterone acetate. [(C) 199 8 Rapid Science Ltd.].