(Background) Hormone-refractory metastatic prostate cancer remains a disease for were limited therapeutic options are available. Therefore, the establishment of newly, more effective chemotherapy is expectatied. Experimental data suggest that PC-3, a human hormone refractory prostate cancer cell line, showed a 2-fold increase in 5-Fluorouracil (5FU) sensitivity in the presence of alpha-2a Interferon (IFNα2a) at 100IU/ml, compared to that without IFNα2a. Based on this data, we treated 11 patients with 5FU and IFNα2a in order to determine the clinical response and toxicity of this combination chemotherapy.
(Methods) One course of this combination chemotherapy consisted of a continuous intravenous infusion of 5FU at 600mg/m²/day for 5 days (D1-D5) with IFNα2a 3 million units (MU) intramuscularly 3 times weekly (D1, D3, D5) followed by a bolus injection of 5FU at 600mg/m² and IFNα2a at 3MU/day on D15 and D22.
(Results) Based on the Response Criteria for Prostate cancer Treatment, one of 9 patients with bony metastasis had partial response, 2 patients with nodal disease on the CT scan obtained partial response. Six of 11 patients had more than 50% decrease in post-therapy prostatic antigen levels, 3 of whom obtained complete response. Significant myelosuppression did not occur. There were no chemotherapy-related deaths.
(Conclusion) These results suggest that the combination of 5FU and IFNα2a, although preliminary, is an active regimen against hormone-refractory metastatic prostate cancer.