No abstract

Nine patients with metastatic breast cancer were treated with a minimum of 6 X 10(6) U/day of beta-interferon (IFN-beta) for at least 6 weeks. In patients whose disease did not progress during this period treatment was continued to a maximum of 13 weeks, while in other patients doses were escalated. With daily treatments over 3 weeks the maximum tolerated dose was found to be around 60 X 10(6) U/day. Fever occurred regularly. The dose-limiting toxicities were granulocytopenia and increasing liver enzymes. No objective remissions were observed. One patient showed stable disease after her cancer en cuirasse had rapidly progressed under chemotherapy. One patient each with nasopharyngeal carcinoma and fibrous sarcoma were also treated without success. IFN-beta at this moderately toxic dose given over a period of 6-13 weeks is of no clinical value in the treatment of metastatic breast cancer in women.

Mafosfamide-cyclohexylamine is a new oxazaphosphorine derivative. It was chosen for phase-I clinical testing because of an expected higher therapeutic index and lack of complete cross resistance in animal tumors compared to cyclophosphamide. The schedule consisted of a single iv dose repeated every three weeks. The compound was found to cause as it's dose limiting toxicity severe pain along the injected vein and acute irritation of mucous membranes. The maximal tolerated dose was around 1000 mg/m2 given as a slow infusion over 2-3 hours. Hematological toxicity was mild. A limited phase-I study with the lysine salt of mafosfamide showed an identical type of toxicity. Mafosfamide given iv in a high-dose intermittent schedule is of little interest for further clinical trials. It is probable, that the severe venous pain and the mucosal irritation are caused by the high local concentration of 4-hydroxy-cyclophosphamide or by a metabolite. An oxazaphosphorine derivative undergoing slower hydrolysis therefore leading to lower active drug concentrations within the injected vein may be more promising.

No abstract

Microangiopathic haemolytic anaemia developed in 5 (out of 14) patients treated with mitomycin C combinations, having received 4 or more treatment cycles. This finding necessitates restricted use of broad and longterm use of mitomycin C, particularly in view of the occasionally fatal outcome of this toxic complication. Adjuvant treatment with mitomycin C does not appear acceptable any longer. Patients treated with mitomycin C should be monitored carefully for occurrence of schistocytosis and platelet deficiency as very early signs of microangiopathic haemolytic anaemia.