Treatment of metastatic renal cell carcinoma with a combination of human lymphoblastoid interferon-alpha and cimetidine.

Human lymphoblastoid interferon-alpha was administered intramuscularly at a dose of 5 x 10(6) units/day to 20 metastatic renal cell carcinoma patients. For potentiating the antitumor effect of interferon, cimetidine was also given to them orally at a dose of 800 mg/day. The combination therapy obtained a complete response in three patients (15%) and a partial response in three (15%). Nine patients (45%) had stable disease and five (25%), progressive disease. All six patients who responded to the combination therapy had been nephrectomized and had pulmonary metastases. Two of them also had metastases to other sites (mediastinal lymph nodes and bone). The pulmonary metastases were significantly more receptive to interferon therapy than those at the other sites. The average times before a response was obtained were 2.2 months for a minor response, 2.7 months for a partial response and 3.0 months for a complete response, and the average duration of response was 26 months. The six patients who responded survived for a significantly longer period than the 14 non-responding patients treated with interferon in combination with cimetidine. The major toxicities encountered were fever, fatigue and anorexia due to interferon, and the combination therapy was well tolerated except in three patients. The results suggest that interferon-alpha and cimetidine combination therapy may be of use in the management of patients with metastatic renal cell carcinoma.