Combined alpha- and gamma-interferon therapy for malignant midgut carcinoid tumors. A phase I-II trial.

A phase I-II trial was initiated to investigate the effects of a combination of alpha- and gamma-interferon in 12 patients with malignant carcinoid tumors. All patients were treated with alpha-interferon at a dose of 5-10 MU, 3-5 times weekly for a median of 22 months and had stable or progressive disease. Gamma-interferon was added at a daily dose of 0.5 MU subcutaneously. After 3 months of treatment 4 patients showed progressive biochemical disease while 8 patients had continuous stable biochemical disease. The dose was escalated to 1 MU daily in 8 patients while 3 continued at lower dose levels. Gamma-interferon was withdrawn from one patient due to mental depression. At 6 months there was 1 partial response, 3 patients with progressive and 7 with stable disease. Half of the patients experienced increased fatigue during the study. Other adverse reactions were skin lesions and myalgia. The combination therapy demonstrated subjective improvement in half of the patients, but lacked antitumoral effects.