Phase I study of taxol administered as a short i.v. infusion daily for 5 days.

Taxol inhibits cell division by promoting the assembly and stabilization of microtubules. This report describes the results of a phase I trial of taxol administered as a short iv infusion daily for 5 days every 4 weeks. Sixteen patients with refractory malignancy received 21 courses of taxol at five doses between 5 and 40 mg/m2/day X 5. The first nine patients received taxol as a 60-minute infusion. Two patients experienced anaphylactoid reactions, one at the 5-mg/m2/day and the second at the 15-mg/m2/day X 5 dose levels. These reactions were characterized by facial flushing, tachypnea, and hypotension within several minutes of drug administration. These anaphylactoid reactions occurred on the first day of treatment in the first patient and on the first day of the second course in the second patient. These reactions may be related to the rapid administration of the polyoxyethylated castor oil (Cremophor EL) vehicle in which taxol is formulated. No anaphylactoid reactions were observed in the seven patients who received taxol as a 6-hour infusion with antihistamine and prednisone premedication. Dose-related myelosuppression was seen; leukopenia (wbc count less than 1000/mm3) and granulocytopenia (granulocytes less than or equal to 200/mm3) occurred on Days 8 and 9 in two of two patients treated at the 40 mg/m2/day X 5 level. Thrombocytopenia was mild, with a platelet nadir of 87,000-95,000/mm3 at the highest dose level. Premedication with glucocorticoids and antihistamines coupled with a prolonged 6-hour infusion permitted taxol to be administered at 30 mg/m2/day X 5 safely without immediate life-threatening reactions.