Phase I and pharmacokinetic study of Genexol-PM, a cremophor-free, polymeric micelle-formulated paclitaxel, in patients with advanced malignancies.
OBJECTIVE
The rationale for developing an alternative paclitaxel formulation concerns Cremophor EL-related side effects, and a novel paclitaxel delivery system might augment its therapeutic efficacy. Genexol-PM is a polymeric micelle formulated paclitaxel free of Cremophor EL. A phase I study was performed to determine the maximum tolerated dosage, dose-limiting toxicities, and the pharmacokinetic profile of Genexol-PM in patients with advanced, refractory malignancies.


METHODS
Twenty-one patients were entered into the study. Genexol-PM was i.v. administered over 3 h every 3 weeks without premedication. The Genexol-PM dose was escalated from 135 mg/m(2) to 390 mg/m(2).


RESULTS
All of the patients were evaluable for toxicity and response. Acute hypersensitivity reactions were not observed. Neuropathy and myalgia were the most common toxicities. During cycle 1, grade 3 myalgia occurred in 1 patient at 230 and 300 mg/m(2), respectively. At 390 mg/m(2), 2 of 3 patients developed grade 4 neutropenia or grade 3 polyneuropathy. Therefore, the maximum tolerated dosage was determined to be 390 mg/m(2). There were 3 partial responses (14%) among the 21 patients. Of the 3 responders, 2 were refractory to prior taxane therapy. The paclitaxel area under the curve from time 0 to infinity and peak or maximum paclitaxel concentration seemed to increase with escalating dose, except at 230 mg/m(2), which suggests that Genexol-PM has linear pharmacokinetics.


CONCLUSIONS
The main dose-limiting toxicities were neuropathy, myalgia, and neutropenia, and the recommended dosage for a phase II study is 300 mg/m(2). Genexol-PM is believed to be superior to conventional paclitaxel in terms of the obviation of premedication and the delivery of higher paclitaxel doses without additional toxicity.
Kim
Tae-You
TY
Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea.
Kim
Dong-Wan
DW
Chung
Jae-Yong
JY
Shin
Sang Goo
SG
Kim
Sung-Chul
SC
Heo
Dae Seog
DS
Kim
Noe Kyeong
NK
Bang
Yung-Jue
YJ
D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use; D000972:Antineoplastic Agents, Phytogenic / Q000009:adverse effects / Q000627:therapeutic use*; D019540:Area Under Curve; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008823:Micelles; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy*; D017239:Paclitaxel / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D013997:Time Factors
D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; D008823:Micelles; D011108:Polymers; C022131:cremophor; D011092:Polyethylene Glycols; D017239:Paclitaxel