Phase I clinical trials with fludarabine phosphate.

There have been six different phase I trials of Fludara I.V. (fludarabine phosphate) in patients with solid tumors and three different phase I trials of Fludara I.V. in patients with acute leukemia. In addition, one trial of the agent given intraperitoneally has also been published. In patients with solid tumors, the two most often used schedules are a daily bolus schedule of 18 to 25 mg/m2/d for 5 days repeated every 28 days, and a 20 mg/m2 loading dose followed by a 48-hour continuous infusion of the agent at a dose of 25 to 30 mg/m2/d. The dose-limiting toxicity in these studies has been myelosuppression. No dosage or schedule could be recommended for patients with acute leukemia because of the severe neurotoxicity (progressive dementia with blindness leading to coma) noted with doses greater than or equal to 96 mg/m2/d for 5 to 7 days. Other toxicities noted in phase I trials have included somnolence, mild to moderate nausea and vomiting, and a rare and reversible interstitial pneumonitis. Of greatest interest is that a profound lymphopenia has been noted as a side effect of Fludara I.V. That toxicity has proven to be of benefit for patients with chronic lymphocytic leukemia, low-grade lymphoma, and mycosis fungoides, all of which are responsive to Fludara I.V. therapy.