Phase II study of 4'-(9-acridinylamino)methanesulfon-m-anisidide (AMSA) in metastatic breast cancer.

A phase II study of 4'-(9-acridinylamino)methanesulfon-m-anisidide (AMSA) was carried out in previously treated patients with metastatic breast cancer. Four of 26 evaluable patients achieved partial responses and four showed minor responses. The maximum tolerated dose of AMSA was 30 mg/m2/day x 3 days and the dose-limiting toxic effect was myelosuppression. Two of the AMSA responders had not responded to initial therapy with an Adriamycin-containing regimen, indicating a lack of cross-resistance between these two DNA binders.