Following a previous EORTC GU-Group study, in which linomide showed some activity in poor prognosis patients, this study was initiated to determine the effect of linomide in more favourable patients. 35 patients with metastatic renal cell carcinoma with good prognostic factors, i.e. good performance status, prior nephrectomy, no prior systemic therapy, and no liver, bone or brain metastases, were treated with linomide, a quinoline derivative with immunomodulating properties, at a dose of 10 mg daily, after an initial dose escalation during the first 4 weeks of treatment. In 29 evaluable patients, no responses were observed (95% confidence interval 0-10%). Best overall response was no change in 9 patients, for a median duration of 4 months. Linomide in this schedule was poorly tolerated, with 17% (6 patients) of patients being withdrawn and 23% (8 patients) having dose reductions due to adverse events, mostly influenza-like symptoms of myalgia, arthralgia and fatigue. Several cases of pericarditis and neuropathy were observed. In spite of selection of favourable prognosis patients and an optimal daily dosing schedule, linomide was not an effective treatment in renal cell carcinoma. In view of toxicity and lack of efficacy, there is no rationale in further testing the drug in this disease.