PURPOSE: Since metastatic renal cell carcinoma has a poor prognosis and treatment strategies, including hormone therapy, chemotherapy and immunotherapy, have little impact on the quality of life and global survival statistics, new interest has recently focused on the combination of immuno-chemotherapy using pyrimidine analogues, such as gemcitabine. MATERIALS AND METHODS: In a phase II study 16 patients with metastatic renal cell carcinoma were treated with 1,000 mg./m. gemcitabine intravenously on days 1, 8, 15 and 28 for 6 months, 3 MU (1 MU = 1 x 10(6) IU) interferon (IFN)-alpha intramuscularly 3 times a week and 4.5 million IU interleukin (IL)-2 subcutaneously daily for 5 days a week for 2 consecutive weeks every month for 6 months. Responding and nonprogressing cases were maintained on immunotherapy consisting of IFN-alpha and IL-2 for further 6 months. RESULTS: In 15 evaluable patients overall response rate (1 complete response plus 3 partial response) was 28% while stable disease was achieved in 7 (47%). Median survival duration was 20 months (range, 9 to 26+) and median time to tumor progression was 14 months (6 to 26+). The complete response lasted 24+ months and partial response lasted 16 months. The regimen was well tolerated with only 1 case of neutropenia (WHO grade 3), while anorexia, fatigue and flu-like symptoms were the most common toxicity problems but were never greater than grade 2. CONCLUSIONS: Despite the small sample size, this study demonstrates that gemcitabine combined with standard doses of IFN-alpha and low doses of IL-2 is effective treatment for metastatic renal cell carcinoma. This biotherapy was well tolerated and resulted in an optimum objective response and relatively long-term survival.