title: A phase II and pharmacokinetic study of 6S-leucovorin plus 5-fluorouracil in patient with colorectal carcinoma.
abstract: Leucovorin (LV) is commonly used as a modulator of 5-fluorouracil (5-FU) cytotoxicity. In patient with colon cancer, the addition of LV to 5-FU improves response rates, and in some trials has improved survival in advanced disease and in the adjuvant setting. Leucovorin is generally administered as a racemic mixture, but the isomers differ substantially in pharmacokinetics and biological activity, with 6S-LV the predominant active component. The current study was undertaken to determine the effect of 6R on the pharmacokinetics of 6S-LV, and to characterize the toxicity and antitumor effect of 5-FU when administered with 6S-LV to patients with advanced colorectal carcinoma. Thirty patients were treated with weekly 5-FU plus high dose 6S-LV. To determine the effects of 6R-LV on the pharmacokinetics of S6-LV, 20 patients were randomly assigned to receive either 250 mg/m2 6S-LV or 500 mg/m2 6R,S-LV as a 2 hour IV infusion on day -2, and the other preparation on day -1, with pharmacokinetics measured each day. The presence of 6R-LV had no effect on the AUC, Clp, Cmax, or terminal phase t1/2 of 6S-LV. The overall response rate was 40% (C.I. 23-60%). The most frequent toxicities were gastrointestinal. In this small cohort, scheduled and delivered dose intensity was positively associated with response (p = 0.05). These results show that there is no pharmacokinetic advantage to the use of 6S-LV rather than 6R,S-LV as a modulator of 5-FU.
authors.affiliation: Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY 14263, USA.
authors.forename: N J
authors.initials: NJ
authors.lastname: Meropol
authors.forename: N J
authors.initials: NJ
authors.lastname: Petrelli
authors.forename: Y M
authors.initials: YM
authors.lastname: Rustum
authors.forename: M
authors.initials: M
authors.lastname: Rodriguez-Bigas
authors.forename: L E
authors.initials: LE
authors.lastname: Blumenson
authors.forename: C
authors.initials: C
authors.lastname: Frank
authors.forename: E
authors.initials: E
authors.lastname: Berghorn
authors.forename: P J
authors.initials: PJ
authors.lastname: Creaven
mesh_terms: D000328:Adult; D000368:Aged; D000931:Antidotes / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002277:Carcinoma / Q000188:drug therapy* / Q000401:mortality / Q000556:secondary; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000401:mortality; D004064:Digestive System / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D015507:Drugs, Investigational / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use; D006801:Humans; D007262:Infusions, Intravenous; D002955:Leucovorin / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use; D008113:Liver Neoplasms / Q000188:drug therapy / Q000556:secondary; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013237:Stereoisomerism; D016896:Treatment Outcome
chemical_list: D000931:Antidotes; D000964:Antimetabolites, Antineoplastic; D015507:Drugs, Investigational; D002955:Leucovorin; D005472:Fluorouracil