A phase I trial of fluorouracil, leucovorin, and recombinant interferon alpha-2b in patients with advanced malignancy

We conducted a phase I trial of fluorouracil (5-FU), leucovorin, (LCV), and recombinant interferon-alpha-2b (rIFN-alpha-2b). The doses of each of the three agents were escalated sequentially. 5-FU and LCV were administered by IV bolus, weekly for 6 weeks and rIFN-alpha-2b was administered by subcutaneous injection, three times weekly for 6 weeks. Twenty-nine patients with advanced cancer (75% colon or pancreatic cancer) were treated. Partial remissions were observed in three patients (10%) with previously untreated colon cancer, colon cancer refractory to 5-FU plus LCV and previously untreated pancreatic cancer, respectively. An additional three patients with pancreatic, prostate, and rectal cancer had a 50% reduction in tumor markers but no change in objective tumor measurements. The toxicity of this regimen was tolerable. The most common toxicities were diarrhea, fatigue, flu-like symptoms, nausea/vomiting, and mucositis. However, no fatal or life-threatening toxicities were observed. We conclude that the combination of 5-FU, LCV, and rIFN-alpha-2b can be safely administered and recommend further evaluation of this regimen in patients with tumors of gastrointestinal origin using doses of 5-FU 600 mg/m2, LCV 500 mg/m2, and rIFN-alpha-2b 10 x 10(6) U.