Inclusion Criteria:

- Histologically confirmed renal cell carcinoma (primary tumour or biopsy/surgery of
metastases)

- Radiologically confirmed metastatic disease

- Surgically removed primary tumour so feasible (nephrectomy or nephron-sparing surgery
as indicated)

- Karnofsky-Performance Status >70%

- Age 19-75 years

- Life expectancy of at least 3 months

- Adequate bone marrow function (i.e. white blood cell count above 3000/μL, platelet
count above 75 000 /μL, hemoglobin above 9 mg/dl)

- Adequate organ function (i.e. serum creatinine, bilirubin and AST below 1.25 x the
upper limit of the institutions' normal range)

- Negative pregnancy test for female patients

- Written informed consent

Exclusion Criteria:

- Age <19 or >75 years

- Karnofsky-Performance Status < 70%

- Untreated or uncontrolled brain metastases

- Second neoplasia

- Primary tumour surgically removable

- Solitary, surgically removable metastases

- Major concomitant diseases of the cardiovascular, respiratory or renal systems, as
well as active systemic infections

- Severe renal disease or liver insufficiency or myeloid dysfunction (including
patients with a history of a disease that is likely to interfere with the metabolism
or excretion of the test medication)

- Other less common diseases as peptic ulcer disease, inflammatory bowel disease,
autoimmune disease (severe known psoriasis, idiopathic thrombocytopenic purpura,
lupus erythematosus, autoimmune hemolytic anemia, scleroderma, rheumatoid arthritis
etc.)

- Drug addiction (including excessive alcohol consumption) within 1 year prior to study
start.

- History of other conditions consistent with decompensated liver disease or other
evidence of bleeding form esophageal varices.

- History of chronic hepatitis and immunsupressiva

- Known HIV Infection

- Evidence of allergy or hypersensitivity against recombinant Interferon alfa-2a or
other components of preparation.

- History of severe psychiatric disease, especially depression. Severe psychiatric
disease is defined as treatment with an antidepressant medication or a major
tranquilizer at therapeutic doses for major depression or psychosis, respectively,
for at least 3 months at any previous time or any history of the following: a
suicidal attempt, hospitalization for psychiatric disease, or a period of disability
due to a psychiatric disease.

- Seizure disorders and /or compromised central nervous system function.

- History of evidence of severe retinopathy

- Patient unwilling or unable to give informed consent

- Pregnancy or breastfeeding