Phase II trial of 5-fluorouracil and alpha-2b interferon in patients with hormone-refractory metastatic prostate cancer.

OBJECTIVES

Metastatic prostate cancer remains a disease with no effective therapy. We treated 13 patients with hormone-refractory metastatic prostate cancer with 5-fluorouracil (5-FU) and alpha-2b interferon. Our objectives were to determine the response rate and toxicity of recombinant alpha interferon and 5-FU in patients with hormone-refractory metastatic prostate cancer.

METHODS

Patients with progressive hormone-refractory metastatic prostate cancer with adequate hematologic and renal function underwent baseline bone scans, computed tomographic (CT) scans of abdomen and pelvis, and measurement of prostate-specific antigen (PSA). Therapy consisted of a 5-day loading course of 5-FU at 500 mg/m2 with alpha-2b interferon 9 million units subcutaneously 3 times weekly followed by weekly 5-FU and alpha interferon 3 times per week.

RESULTS

When PSA was used as a response parameter with modified National Prostatic Cancer Project (NPCP) criteria, no objective responses were seen. Using NPCP criteria alone, 5 patients had stable disease. Post-therapy PSA values increased from baseline in 8 of 11 patients (2% to 72%) and declined in 3 patients (3% to 16%). Frequent dosage modifications were required with the dose intensity of 5-FU and alpha interferon of 57% and 58%, respectively. Toxicity was significant, with 31% of patients having grade 3 to 4 mucositis and 46% grade 3 to 4 fatique.

CONCLUSIONS

5-FU and alpha interferon, when administered at the dosage and schedule utilized in this study, have no clinically significant activity and are associated with unacceptable toxicity in patients with metastatic prostate cancer. The role of PSA as an indicator of response remains unclear.