Progress report on two clinical trials in women with advanced breast cancer. Trial I: tamoxifen versus tamoxifen plus aminoglutethimide. Trial II: aminoglutethimide in patients with prior tamoxifen exposure.

A progress report is presented on two on-going clinical trials in women with advanced breast cancer. In Trial I to date, 56 patients have been randomized to tamoxifen (TAM) alone or TAM plus aminoglutethimide (AG) (plus hydrocortisone). Patients failing TAM can then receive AG. The two groups are reasonably well balanced with respect to prior hormonal therapy exposure (TAM, 19%; TAM plus AG, 17%), age, disease-free interval, performance score, and estrogen receptor status. The TAM plus AG group has a higher incidence of visceral dominant disease (41 versus 26%) and prior chemotherapy exposure (41 versus 33%). Responses have been observed in 7 of 27 (26%) patients on TAM and 11 of 28 (39%) on TAM plus AG. Median times to treatment failure (defined as disease progression, unacceptable toxicity, or patient refusal) are 211 and 123 days, respectively (log-rank on time to treatment failure, p = 0.87). Toxicity is greater for TAM plus AG with a higher incidence of skin rash, lethargy, and dizziness. Thrombotic events were seen in one patient on TAM and two patients on TAM plus AG. One patient on TAM plus AG developed leukopenia and sepsis. The data are too preliminary for one to draw firm conclusions regarding relative efficacy. In TRial II to date, 35 patients with prior tamoxifen exposure have received AG. The mean number of prior systemic therapies is 3.2 (range, 1 to 7). The response rate is 20% and similar with (21%) or without (19%) prior chemotherapy exposure. The median time to treatment failure is 92 days. One patient developed leukopenia and sepsis. Additional patient accrual is necessary to allow characterization of potential efficacy within prognostically important subsets.