Schedule-selective biochemical modulation of 5-fluorouracil: a phase II study in advanced colorectal cancer.

Based on experimental findings suggesting that 5-fluorouracil (FUra) may have different mechanisms of action depending on the schedule of administration, we generated the hypothesis that biochemical modulation of this fluoropyrimidine should be schedule specific. We thus tested the activity of a hybrid regimen consisting of two biweekly cycles of FUra bolus (600 mg/m2) modulated by pretreatment (24-h interval) with methotrexate (200 mg/m2), alternating with a 3-week continuous infusion of FUra (200 mg/m2/day) modulated by low-dose (6S)leucovorin (20 mg/m2 bolus weekly). Thirty-three consecutive patients with advanced measurable colorectal cancer and no prior therapy for metastatic disease entered the study from February 1992 to August 1993. They were treated with two biweekly cycles of FUra bolus (600 mg/m2) preceded by (24-h interval) methotrexate (200 mg/m2), alternating with a 3-week continuous infusion of FUra (200 mg/m2/day) modulated by low-dose (6S)leucovorin (20 mg/m2 bolus weekly). The median Eastern Cooperative Oncology Group performance status was 1; the liver was the only metastatic site in 17 patients. Treatment outcome was evaluated by computed tomographic scan in all patients, except for two. Three complete and 13 partial responses were obtained among these 33 patients (response rate, 48%; 95% confidence limits, 31-66%). Performance status (Eastern Cooperative Oncology Group) influenced clinical response. The combined complete response and partial response rate was 69%, 33%, and 25% in patients with an Eastern Cooperative Oncology Group performance status of 0, 1, and 2, respectively (chi2, 4.6, P = 0.032, two-tailed Mantel test for trend). After a median follow-up time of 26 months, 10 patients are still alive. The median progression-free survival and overall survival were 9.5 and 20.2 months, respectively. No toxic deaths or grade 4 toxicity occurred. The incidence of grade 3 toxicity per patient in any cycle was: mucositis 6%, diarrhea 3%, and vomiting 3% for the bolus part and 21%, 3%, and 6%, respectively, for the continuous infusion part of the regimen. Hand-foot syndrome occurred in 27% of the patients treated with the continuous infusion regimen.

Adjuvant Treatment of Colorectal Cancer in the Elderly.

From March 1992 until January 1994, 1,014 patients radically resected for Dukes' B(2), B(3) or C colon cancer were randomized to receive FU plus levamisole or FU plus leucovorin (LV) plus levamisole. Only 41% of patients older than age 70 years, as compared to 53% of those younger, have completed the treatment as planned. This poorer compliance was not associated with a higher incidence or degree of toxicity. Only a small difference in percentages was detected between the age groups of patients requiring dose reductions or treatment delays, while the percentages of patients that had their treatment discontinued was markedly increased in the older age group, without a parallel increase in severe toxicity. Preliminary results suggest that adjuvant chemotherapy with FU plus levamisole or FU plus LV plus levamisole is well tolerated by elderly patients and is not associated with greater toxicity in patients over 70 years of age than in younger patients. The lower adherence to the treatment plans in older patients may be due to reluctance by physicians and families to administer chemotherapy due to the misconception that the elderly are more prone to adverse reactions.

5-Fluorouracil plus 5-methyltetrahydrofolate in advanced pancreatic cancer. GLISP (Gruppo Ligure Studio Pancreas).

A total of 20 patients with advanced pancreatic adenocarcinoma were enrolled in a phase II trial testing the activity of 5-fluorouracil given at 370 mg/m2 as a rapid i.v. bolus for 5 consecutive days, preceded by a rapid i.v. bolus of 200 mg/m2 5-methyltetrahydrofolic acid. The treatment was repeated every 4 weeks. The median age of the patients was 68 years and their median Eastern Cooperative Oncology Group (ECOG) performance status was 1. There were 7 patients with locally advanced disease and 13 with distant metastases (median, 2 sites). A median of 3 monthly cycles of treatment (range, 1-7) were given, with a corresponding dose intensity of 396 mg/m2 per week (86% of that planned). No complete response, 1 partial response, and 8 cases of disease stabilization were obtained. In general the regimen was well tolerated, with only 2 patients suffering from grade 3 stomatitis or diarrhea; the most common toxicity was nausea, which was experienced by almost 50% of the patients. The combination of 5-methyltetrahydrofolate plus 5-fluorouracil appears as little effective in this disease as 5-fluorouracil plus 5-formyltetrahydrofolate (leucovorin). It is suggested that bolus 5-fluorouracil is so inactive as an "effector agent" against pancreatic cancer that its biochemical modulation with exogenous high-dose reduced folates cannot improve the therapeutic outcome produced by the fluoropyrimidine in these patients.

Activity of continuous-infusion 5-fluorouracil in patients with advanced colorectal cancer clinically resistant to bolus 5-fluorouracil.

We have recently demonstrated that continuous-infusion (CI) 5-fluorouracil (FU) eradicates human colon carcinoma cells made resistant to bolus FU in vitro. In addition, in the same experimental system, the mechanisms of resistance to pulse and CI FU were found to be different. These observations led us to test the clinical activity of a standard regimen of CI FU (300 mg/m2 per day) in a cohort of 15 patients with advanced measurable colorectal cancer who were in progression after having failed to respond to bolus treatment with FU alone (3 patients) or FU combined with high-dose 6-S-leucovorin (LV) (12 patients). The median age of the patients was 68 years, and their median Eastern Cooperative Oncology Group performance status (ECOG PS) was 1. No myelotoxicity was observed. Mild diarrhea, mucositis, and vomiting occurred in 32%, 26%, and 19% of the patients, respectively, with no WHO grade 3 or 4 episodes being noted. In all, 6 of 15 patients complained of hand-foot syndrome, which was severe in 2 instances, lasting approximately 1 week. Overall, 1 partial response and 6 instances of disease stabilization, including 3 minor responses, were obtained both in patients who had been pretreated with pulse FU alone and in patients who had failed first-line treatment with FU + LV. Finally, 8 patients failed CI FU. In conclusion, these results, obtained in patients who were clearly progressing after having failed first-line treatment, support our experimental finding that resistance to bolus FU may be overcome by CI FU and extend this possibility to patients who are resistant to bolus treatment with FU + LV.

Phase II study of 5-fluorouracil plus leucovorin and interferon alpha 2b in advanced colorectal cancer.

15 untreated patients with advanced measurable colorectal cancer along with other 29 patients in progression after failing first line chemotherapy with fluoropyrimidines received 5-fluorouracil (5FU) 500 mg/m2 given as a weekly bolus at mid-infusion of leucovorin (LV), 500 mg/m2 administered intravenously over 2 h and interferon alpha 2b (IFN) 3 x 10(6) U given intramuscularly every other day. All patients had their previous chemotherapy at least 4 weeks prior to 5FU-LV-IFN. 5 patients discontinued the three drug regimen due to toxicity (intense weakness, fever and influenza-like symptoms in 4 patients; diarrhoea in 1 patient) however no grade IV toxicity was observed. IFN administration was reduced to twice/weekly in 5 patients due to influenza-like symptoms. 1 complete response and 5 partial responses were observed (13.6% response rate); the complete response was obtained in a patient resistant to 5FU: the response rate was only twice as much in untreated patients (3/15 patients, 20%) compared with that in patients previously treated with fluoropyrimidines (3/29 patients, 10.3%). Therefore, modulation of 5FU with LV plus IFN at the doses and schedules employed in this study may rarely overcome clinical resistance to the fluoropyrimidine and the addition of IFN does not appear to enhance the activity of 5FU plus LV.