INTERFERON VERSUS INTERFERON PLUS PREDNISONE REMISSION MAINTENANCE THERAPY FOR MULTIPLE-MYELOMA - A SOUTHWEST-ONCOLOGY-GROUP STUDY

Purpose: We evaluated the vincristine, doxorubicin, and dexamethasone (VAD) regimen alone or with chemosensitizers for remission induction a nd interferon (IFN) versus IFN plus prednisone (IFN/P) for remission m aintenance in previously untreated multiple myeloma. Patients and Meth ods: Two hundred thirty-three patients were registered for remission-i nduction therapy with VAD or VAD plus the chemosensitizers verapamil a nd quinine. Patients who achieved remission were randomized to mainten ance therapy with IFN alpha 3 MU in the evening three times weekly or IFN plus 50 mg of prednisone (IFN/P) on the morning after IFN until re lapse. Results: two hundred twenty-nine patients were eligible for ind uction. Fatal toxicities in nine patients who received VAD plus verapa mil and quinine led to closure of this arm after 47 registrations. Sub sequently, all patients received VAD induction. Despite the high early mortality rate on VAD plus sensitizers, overall survival by induction arm did not differ for median or 5-year survival with approximately 4 0% of patients surviving 5 years. Eighty-nine eligible patients who ac hieved remission were randomized to maintenance. Patients who received IFN/P had improved progression-free survival (median, 19 v9 months fo r IFN; P = .008). After 48 months, progression-free survival on IFN/P was at the thirtieth percentile, whereas it was below the tenth percen tile on IFN alone. Median survival from start of maintenance was long on both arms (57 months for IFN/P v46 months for IFN; P = .36). Conclu sion: IFN/P was more effective than IFN alone. Improved relapse-free s urvival may be attributable to IFN/P or to the use of prednisone for m aintenance. This latter alternative is currently being studied. (C) 19 98 by American Society of Clinical Oncology.