FAVORABLE CLINICAL-RESPONSES IN SUBSETS OF PATIENTS FROM A RANDOMIZED, MULTIINSTITUTIONAL MELANOMA VACCINE TRIAL

Background: A phase III, randomized, double-blind, multi-institutional trial was performed evaluating active specific immunotherapy using va ccinia melanoma oncolysate (VMO) in the surgical adjuvant setting in p atients with stage II melanoma (UICC staging). The first interim analy sis showed no significant difference in disease-free and overall survi val. The data were further analyzed to identify subsets of patients wi th improved outcome when treated with VMO. Methods: Patients received either VMO or placebo of live vaccinia vaccine virus (V), once a week for 13 weeks and then once every 2 weeks for an additional 39 weeks or until recurrence. Having stratified patients according to sex, age, n umber of positive nodes, tumor thickness, and clinical stage, data wer e analyzed for disease-free survival and overall survival. Results: Ma le patients showed a 17% difference in overall survival at 4 years whe n treated with VMO (p = 0.19). A subset of male patients < 57 years of age with one to five positive nodes showed a 30% difference at 4 year s with VMO (p = 0.06). Patients with clinical stage I but pathological stage II disease (both male and female), who had undergone prophylact ic node dissection, showed a 23% difference in survival at 3 years wit h VMO (p = 0.11). Conclusions: This subset analysis shows encouraging survival benefit in certain subsets of patients and an increasing tren d in overall survival. Further follow-up of this phase III trial from a second interim analysis will be forthcoming.