The aim of this study was to evaluate the response characteristics of vincristine, adriamycin and dexamethasone (VAD) as a first-line chemotherapy and to determine the efficacy of maintenance alpha-interferon (alpha-IFN) in multiple myeloma (MM). Between January 1985 and December 1994, a prospective trial was performed in stage II and III MM patients. The study population received only VAD with no maintenance therapy before 1990 (n=31), and those recruited after 1990 (n=33) were planned to be maintained with alpha-IFN (5 mU, 3 times per wk) during the plateau to a maximum of 2 yr. Median follow-up duration (44 vs. 39 months), time to response (3.4 vs. 3.5 months) and rate of objective response (61.3%, 19/31 and 63.6%, 21/33) were similar in VAD-only and VAD+IFN groups, respectively. The survival analyses revealed higher median progression-free (39.6 vs. 12 months) and overall survival (65+ vs. 24 months) durations in VAD+IFN group compared to VAD-only group. VAD regimen was well tolerated and IFN-related side effects were reversible. These findings denote that IFN maintenance prolongs the duration of response obtained by VAD.