A phase II trial of cyclosporin A in the treatment of refractory metastatic colorectal cancer.

Cyclosporin A (CSA) is an immunosuppressive agent that in experimental models has antiproliferative activity against colon cancer and other human neoplasms. A phase II trial was conducted to evaluate CSA in refractory colorectal malignancies. CSA was administered at a starting dose of 7.0 mg/kg twice daily (total dose, 14 mg/kg/day) and escalated to tolerance. Of 18 patients with measurable disease, 17 were evaluable. All had been treated with one fluorouracil-containing regimen. The European Cooperative Oncology Group (ECOG) performance status was 0 or 1 in 17 of the 18 patients. No objective responses were seen. Four patients maintained stable disease lasting from 10 to 75+ weeks. Significant toxicity occurred in 9 of 17 (53%) patients. Dose reduction was necessary in 10 of 17 (59%). Sustained escalation beyond the initial dose was possible in only two cases. Toxicities included nausea and vomiting (71%), nephrotoxicity (41%), fatigue (35%), flu-like symptoms (29%), and neurotoxicity (18%). In the dose and schedule employed in this trial, CSA is ineffective in refractory colorectal cancer and produces significant toxicity.