First-line, single-agent Herceptin (R) (trastuzumab) in metastatic breast cancer: a preliminary report

Following confirmation of the appropriate dosage, safety and potential effi cacy of Herceptin(R) (trastuzumab) in small-scale phase I and II trials inv olving patients with refractory disease, a large trial was conducted in 222 patients with breast cancer who had relapsed after one or two chemotherapy regimens for their metastatic disease. The results showed a positive and d urable overall response rate (15% according to a response evaluation commit tee (REC) assessment) using trastuzumab monotherapy (initial dose 4 mg/kg i ntravenously (i.v.) followed by 2 mg/kg i.v. weekly). In another recently c ompleted phase II trial, 113 patients were randomised to two dose levels (i nitial dose of 4 mg/kg i.v, dose followed by 2 mg/kg i.v, weekly, or initia l dose of 8 mg/kg followed by 4 mg/kg i.v. weekly) of single-agent trastuzu mab as first-line therapy for metastatic disease. The preliminary overall r esponse rate was 4 23% based on investigator assessment, and tolerability w as excellent as in previous trials; efficacy was similar in both dose group s, but the side-effects tended to be more frequent in the higher dose group , The preferred dosage is therefore the same as that currently recommended, i.e. an initial dose of 4 mg/kg i.v. followed by 2 mg/kg weekly i.v. until disease progression, (C) 2001 Elsevier Science Ltd. All rights reserved.