Journal of Clinical Oncology, Vol 12, 1902-1909, Copyright © 1994 by American Society of Clinical Oncology
Phase I evaluation of a water-soluble etoposide prodrug, etoposide phosphate, given as a 5-minute infusion on days 1, 3, and 5 in patients with solid tumors
DR Budman, LN Igwemezie, S Kaul, J Behr, S Lichtman, P Schulman, V Vinciguerra, SL Allen, J Kolitz and K Hock
Don Monti Division of Oncology, Department of Medicine, North Shore University Hospital-Cornell University Medical College, Manhasset, NY 11030.
PURPOSE: To determine the toxicities, maximum-tolerated dose (MTD), and
pharmacology of etoposide phosphate, a water-soluble etoposide derivative,
administered as a 5-minute intravenous infusion on a schedule of days 1, 3,
and 5 repeated every 21 days. PATIENTS AND METHODS: Thirty-six solid tumor
patients with a mean age of 63 years, performance status of 0 to 1, WBC
count > or = 4,000/microL, and platelet count > or = 100,000/microL,
with normal hepatic and renal function were studied. Doses evaluated in
etoposide equivalents were 50, 75, 100, 125, 150, 175, and 200 mg/m2/d.
Etoposide in plasma and urine and etoposide phosphate in plasma were
measured by high- performance liquid chromatography (HPLC). Eleven of 36
patients were treated with concentrated etoposide phosphate at 150 mg/m2/d.
RESULTS: Grade I/II nausea, vomiting, alopecia, and fatigue were common.
Leukopenia (mainly neutropenia) occurred at doses greater than 75 mg/m2,
with the nadir occurring between days 15 and 19 posttreatment. All effects
were reversible. Hypotension, bronchospasm, and allergic reactions were not
observed in the first 25 patients. The MTD due to leukopenia was determined
to be between 175 and 200 mg/m2/d. In 11 patients treated with concentrated
etoposide phosphate, no local phlebitis was noted, but two patients did
develop allergic phenomena. The conversion of etoposide phosphate to
etoposide was not saturated in the dosages studied. Etoposide phosphate had
peak plasma concentrations at 5 minutes, with a terminal half-life (t1/2)
of 7 minutes. Etoposide reached peak concentrations at 7 to 8 minutes, with
a t1/2 of 6 to 9 hours. Both etoposide phosphate and etoposide demonstrated
dose-related linear increases in maximum plasma concentration (Cmax) and
area under the curve (AUC). CONCLUSION: Etoposide phosphate displays
excellent patient tolerance in conventional dosages when administered as a
5- minute intravenous bolus. The suggested phase II dose is 150 mg/m2 on
days 1, 3, and 5. The ability to administer etoposide phosphate as a
concentrated, rapid infusion may prove of value both in the outpatient
clinic and in high-dose regimens.