A phase II study of 9-nitro-camptothecin in patients with previously treated metastatic breast cancer.

Aims: This Phase II study was conducted to determine the efficacy and toxicity of 9-nitro-camptothecin (9-NC) in patients with previously treated metastatic breast cancer. Pharmacokinetic samples were obtained to investigate the correlation of plasma 9-NC exposure with clinical response and toxicity.

Patients And Methods: Eligible patients had histologically confirmed metastatic breast cancer with measurable or evaluable disease. Patients must have received one or two prior chemotherapy regimens for metastatic disease. 9-NC was given orally, 1.5 mg/m(2)/day for 5 days each week; response was assessed every 8 weeks. Pharmacokinetic samples were obtained on day 1 of weeks 1 and 5.

Results: Eighteen patients were enrolled between September 1999 and May 2000; seventeen patients were evaluable for response. The most common toxicities were nausea, vomiting, urinary symptoms, fatigue and diarrhea. No objective responses were observed; six patients had stable disease. 9-NC apparent clearance ranged from 0.57 to 55.08 L/h (median 5.91 L/h); 9-NC area under the curve ranged from 38 to 2130 ng/ml x h (median 377 ng/ml x h). There was no relationship between pharmacokinetic parameters and individual patient toxicity.

Conclusion: 9-NC has limited activity in patients with previously treated metastatic breast cancer. Though 9-NC has substantial pharmacokinetic variability in this patient population; no correlation was found between pharmacokinetic variables and toxicity.