The purpose of the trial is to identify the recommended dose of sorafenib and sirolimus for combination therapy in subsequent phase 2 trials.

Inclusion Criteria:

• Patients with histological or cytological confirmed advanced solid tumor, which is refractory to standard therapies or for which no standard therapy exists and for which there is a rationale for the therapeutic use of a combination of sorafenib and sirolimus (especially metastic RCC, malignant melanoma, HCC, NSCLC, pancreatic cancer, hormone refractory prostate cancer).
• Men or women of at least 18 years
• Patients who have an ECOG status of 0 or 1
• Patients who have a life expectancy of at least 12 weeks
• Adequate bone marrow, liver and renal function
• Negative pregnancy test for female patients of childbearing potential
• Women and men enrolled into this trial must use adequate birth control measures during the course of the trial.
• Signed informed consent

Exclusion Criteria:

• History of serious cardiac disease
• Active clinically serious bacterial, viral or fungal infections (> grade 2).
• Known history of human immunodeficiency virus (HIV) infection or chronic hepatitis B or C.
• Clinically symptomatic brain or meningeal metastasis.
• Patients with seizure disorders requiring medication (such as steroids or antiepileptics).
• Patients with evidence or history of bleeding diathesis.
• Substance abuse, medical, psychological or social conditions that may interfere with the patients participation in the study or evaluation of the study results.
• Concomitant treatment with strong CYP3A4 inductors (such as rifampicin, St. John´s Wort) or CYP3A4 inhibitors (such as ketoconazole, voriconazole, itraconazole, diltiazem, verapamil, erythromycin). Moderate or weak CYP3A4 modifiers should be used concomitantly only after careful assessment of risk-benefit ratio. Concomitant use of carbamazepine, phenobarbital, phenytoin or chronic use of dexamethasone is excluded