Phase I evaluation of spirogermanium and 5-fluorouracil in colorectal carcinoma.

We have conducted a phase I study to evaluate the toxicity and tolerance of a 5 day continuous infusion of spirogermanium and 5-fluorouracil, (5-FU). The 5-FU was administered via a peripheral vein at 1000 mg/M2/day for 5 days by continuous infusion. Simultaneously, spirogermanium was administered via an indwelling central venous catheter by continuous infusion for 5 days starting at 50 mg/M2/day and escalating to 250 mg/M2/day. Sixteen patients received a total of 54.5 courses of therapy. The most common and severe toxicity was neurotoxicity. Mild to moderate gastrointestinal toxicity also occurred. No significant hematologic toxicity occurred. Two partial responses occurred lasting 11 and 20.5 months, both at the 100 mg/M2/day level of spirogermanium. The recommended phase II dosages are 5-FU 1000 mg/M2/day and spirogermanium 200 mg/M2/day by 5 day continuous infusion with escalation of the spirogermanium in selected individuals. Patients on long term therapy should have close neurologic evaluation and follow up. Consideration should also be given to evaluating a group of patients at the 100 mg/M2/day level of spirogermanium due to the responses seen at this level.