Pyridoxine therapy for palmar-plantar erythrodysesthesia associated with continuous 5-fluorouracil infusion

Summary The limiting toxicity of low dose continuous infusion 5-fluorouracil (200–300 mg/m²/day) is often palmarplantar erythrodysesthesia (PPE). PPE developed in 16/25 patients (exact 95% confidence interval of 42% –82%) with metastatic colon cancer enrolled in a phase II trial. In this trial, 5-FU was given continuously at a dose of 200 mg/m²/day until toxicity or progressive disease forced discontinuation.The first signs of the syndrome developed at a median of 2 months following infusion initiation and, unless treatment was interrupted, became progressively worse. The incidence of moderate to severe PPE was 71% in the 14 previously untreated patients (exact 95% confidence intervals of 42–92%). Seventy-eight percent of the responders in the no prior treatment group developed PPE. The incidence of moderate to severe PPE was only 27% in the 11 previously treated patients (exact 95% confidence intervals of 6–61%). The higher incidence of PPE in the previously untreated patients probably resulted from a longer total infusion time (median = 7.3 months) than the previously treated (median = 4.5 months). The longer infusion time in turn was a result of the higher response rates (64 vs 18%) in the previously untreated versus treated groups.Five previously untreated patients who developed PPE received 50 or 150 mg of pyridoxine/day when moderate PPE changes were noted. Reversal of PPE without interruption of the 5-FU was seen in 4/5 patients. Four of these patients who received pyridoxine had responded to 5-FU treatment. No adverse affect of pyridoxine on clinical response was noted.The five previously untreated patients who received pyridoxine for PPE continued 5-FU for a median of 6 months after development of the syndrome. The six previously untreated patients who did not receive pyridoxine when they developed PPE were able to continue 5-FU for a median of only 2.5 months after development of the syndrome. A similar number of clinical responders to 5-FU were present in both groups.Considering the high incidence of PPE and response in previously untreated colon cancer patients who receive protracted continuous 5-FU, prophylactic pyridoxine in conjunction with this treatment modality might be useful.