Randomized crossover study evaluating the effect of gemcitabine infusion dose rate: Evidence of auto-induction of gemcitabine accumulation

Peter Grimison, Peter Galettis*, Susan Manners, Maria Jelinek, Ekkaphon Metharom, Paul L de Souza, Winston Liauw, Matthew J Links

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

20 Citations (Scopus)


Controversy exists over the optimal dose rate for administration of gemcitabine. There is a strong pharmacologic rationale for increased intracellular accumulation with prolonged infusions, but this failed to translate into a significant benefit in a large randomized study. The purpose of this study was to compare the intracellular pharmacokinetics of gemcitabine given for 30 minutes or for 100 minutes in a crossover design.

Patients and Methods
We randomly assigned 33 patients to a standard dose of 1,000 mg/m2 over either 30 minutes or 100 minutes. At the second week, they were transferred to the alternate schedule. Blood samples were collected at various times after the gemcitabine infusion. Gemcitabine and difluorodeoxyuridine were measured in plasma by high-performance liquid chromatography (HPLC), and gemcitabine-triphosphate was measured by HPLC in leukocytes.

Intracellular accumulation was greater during the 100-minute infusion, which was consistent with previous data. This effect was confounded by an increase in gemcitabine-triphosphate accumulation between weeks 1 and 2, which was consistent with self-induction of gemcitabine accumulation. There was significant heterogeneity: 27% of patients had greater WBC accumulation during the 30-minute infusion (regardless of treatment order). Patients with relatively greater levels of gemcitabine-triphosphate in WBCs tended to have less under-dosing and a greater reduction in midcycle neutrophils. However, this observation did not correlate with plasma gemcitabine levels.

This work identifies significant variations in intracellular gemcitabine-triphosphate accumulation between and within individuals, and it provides evidence that this variation has potential clinical significance. The observed self-induction of gemcitabine metabolism has broad implications for the dosing of nucleoside analogs.
Original languageEnglish
Pages (from-to)5704-5709
Number of pages6
JournalJournal of Clinical Oncology
Issue number36
Publication statusPublished - 20 Dec 2007
Externally publishedYes


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