title: Severe sequence-specific toxicity when capecitabine is given after Fluorouracil and leucovorin.
abstract: OBJECTIVE
  Options for single-agent fluoropyrimidine adjuvant therapy after bowel cancer resection include intravenous fluorouracil with leucovorin (FU/LV) or oral capecitabine. These treatments have similar efficacy but differ in convenience and toxicity. We therefore wished to compare their overall acceptability to patients.
  
  
  METHODS
  Patients scheduled for adjuvant single-agent fluoropyrimidine therapy were randomly assigned to receive once-weekly FU/LV (425 mg/m(2) FU, 45 mg LV) for 6 weeks, followed by two 3-week cycles of capecitabine (1,250 mg/m(2) twice daily, days 1 through 14), or the same treatments but in reverse order. After 12 weeks, the patients were asked which treatment they preferred, and received the preferred treatment for an additional 12 weeks. The primary end point was patient preference.
  
  
  RESULTS
  After 40 of the planned 74 patients had been randomly assigned, real-time adverse event monitoring led to early trial closure because of excess sequence-specific toxicity. Eleven of 14 patients (79%) receiving capecitabine as their second treatment experienced grade >/= 3 toxicity. This compared with five of 18 patients (28%) receiving capecitabine as the first treatment, and no patients receiving FU/LV as the first treatment (zero of 16) or the second treatment (zero of 12). Similar imbalances were seen in the proportion of patients requiring interruption of treatment.
  
  
  CONCLUSIONS
  In chemotherapy-naïve patients, capecitabine produced more toxicity than FU/LV, but at levels in line with previously reported data. However, treatment with capecitabine after FU/LV caused markedly increased toxicity, indicating a sequence-specific interaction. The mechanism has not been determined, but interaction with intracellularly retained folate after FU/LV therapy is a possibility. Oncologists need to be aware of this risk if considering crossing patients over from FU/LV to capecitabine-based regimens.
authors.affiliation: Cancer Research UK Centre, St James's Institute of Oncology, St James's University Hospital, Leeds LS9 7TF, United Kingdom.
authors.forename: Ivo M
authors.initials: IM
authors.lastname: Hennig
authors.forename: Jay D
authors.initials: JD
authors.lastname: Naik
authors.forename: Sarah
authors.initials: S
authors.lastname: Brown
authors.forename: Alex
authors.initials: A
authors.lastname: Szubert
authors.forename: David A
authors.initials: DA
authors.lastname: Anthoney
authors.forename: David P
authors.initials: DP
authors.lastname: Jackson
authors.forename: Alan M
authors.initials: AM
authors.lastname: Melcher
authors.forename: S Michael
authors.initials: SM
authors.lastname: Crawford
authors.forename: Christopher
authors.initials: C
authors.lastname: Bradley
authors.forename: Julia M B
authors.initials: JM
authors.lastname: Brown
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Seymour
mesh_terms: D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000009:adverse effects*; D001707:Biopsy, Needle; D000069287:Capecitabine; D017024:Chemotherapy, Adjuvant; D003082:Colectomy / Q000379:methods; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000401:mortality* / Q000473:pathology / Q000601:surgery; D018592:Cross-Over Studies; D003841:Deoxycytidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004347:Drug Interactions; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives*; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D002955:Leucovorin / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011336:Probability; D011446:Prospective Studies; D012016:Reference Values; D018570:Risk Assessment; D016037:Single-Blind Method; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D003841:Deoxycytidine; D000069287:Capecitabine; D002955:Leucovorin; D005472:Fluorouracil