Association of Paclitaxel pharmacokinetics with the development of peripheral neuropathy in patients with advanced cancer.
OBJECTIVE
The shortening of infusion time from 3 to 1 hour decreases the systemic exposure (area under the curve, AUC) of total and unbound paclitaxel but increases the AUC of its vehicle Cremophor EL, whereas the time above total paclitaxel concentrations of 0.05 micromol/L (T >0.05) remains almost constant. As both Cremophor EL and paclitaxel are neurotoxic, we evaluated their pharmacodynamic effects on the development of peripheral neuropathy as the most important nonhematologic toxicity.


METHODS
Patients with advanced cancer of different origin were randomized to receive a maximum of 12 weekly-given 1- or 3-hour infusions of 100 mg/m2 paclitaxel (Taxol). Twenty-four patients were assessable for both pharmacokinetics and peripheral neuropathy development evaluated by a clinical scoring system including sensory symptoms, strength, tendon reflexes, and vibratory sense.


RESULTS
Patients with peripheral neuropathy development (n=14) received more weeks of therapy (P=0.056) and showed significantly higher T(>0.05) (P=0.022) and overall systemic drug exposures (weeks of therapy x AUC) for total paclitaxel (P=0.002) and unbound paclitaxel (P=0.003) than those without peripheral neuropathy. In Kaplan-Meier analyses, T(>0.05) > or = 10.6 hours (P=0.023), AUC of total paclitaxel > or = 4.7 microg/mL x hour (P = 0.047), and AUC of unbound paclitaxel > or = 0.375 microg/mL x hour (P = 0.095) were identified as being potential factors for peripheral neuropathy development. In a Cox regression analysis, only T(>0.05) > or = 10.6 hours remained as an independent risk factor (relative risk, 18.43; P = 0.036) after adjusting for prior vincamycin (relative risk, 11.28; P = 0.038).


CONCLUSIONS
From the results obtained in this study, it is concluded that exposure to paclitaxel but not Cremophor EL is associated with peripheral neuropathy development.
Department of Hematology and Oncology, University of Freiburg Medical Center, Freiburg, Germany. mielkes@nhlbi.nih.gov
Stephan
S
Mielke
Alex
A
Sparreboom
Seth M
SM
Steinberg
Hans
H
Gelderblom
Clemens
C
Unger
Dirk
D
Behringer
Klaus
K
Mross
D000328:Adult; D000368:Aged; D000972:Antineoplastic Agents, Phytogenic / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D019540:Area Under Curve; D005260:Female; D006801:Humans; D007260:Infusion Pumps; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D017239:Paclitaxel / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D010523:Peripheral Nervous System Diseases / Q000139:chemically induced*; D016016:Proportional Hazards Models; D013997:Time Factors; D016896:Treatment Outcome
D000972:Antineoplastic Agents, Phytogenic; D017239:Paclitaxel