LONG-TERM RESULTS OF CONTINUOUS TREATMENT WITH RECOMBINANT INTERFERON-ALPHA IN PATIENTS WITH METASTATIC CARCINOID-TUMORS - AN ANTIANGIOGENIC EFFECT

This study investigated the efficacy of long-term continuous and dose- escalated interferon-alpha (IFN) treatment in patients with progressiv e carcinoid tumors, In this single-institution, phase II study 16 chem otherapy-naive, eligible patients were entered, Interferon treatment c onsisted on 5 MIU IFN three times weekly s.c. until radiologic progres sion, In case of progression the dose was increased to 10 MIU. Radiolo gic and biochemical evaluation was done monthly and thereafter 3 month ly, We have treated 16 patients of whom 15 are evaluable for tumor res ponse, Calculated by standard response criteria, three patients experi enced a partial response, Another three had an important minor respons e. Median response duration was 24 months (range 18-51 months), Bioche mical responses were observed in nine out of 12 patients with an eleva ted 5-hydroxyindoleacetic acid excretion. The serum neuron-specific en olase proved a reliable marker for both response end progression, In t he one patient progressive after 3 months, a dose increment to 10 MIU was without effect. In patients initially not progressing or respondin g to 5 MIU, escalation to 10 MIU had a short lasting beneficial effect in three cases. The radiological characteristics and the kinetics of these responses are compatible with an anti-angiogenic effect of IFN, This study of IFN in carcinoid tumors confirms the activity in this di sease. Our results demonstrate the necessity of initiating treatment o nly in radiologically progressive patients and continuing this treatme nt until progression, We feel that currently the activity of IFN in me tastatic carcinoid tumors compares favorably with that of systemic che motherapy in patients with progressive disease.