BCG stimulation of immune responsiveness in patients with malignant melanoma. Preliminary report.

Abstract

Thirteen patients with malignant melanoma without clinically detectable disease but high likelihood of relapse were treated with a Phase I immunotherapy program of live BCG given by scarification. Two dose levels were used: high dose = 6 × 108 live organisms, and low dose - 6 × 107 live organisms. The early serial immunologic data are reported, and these are cor elated with BCG dose and clinical status. Six of six receiving low dose BCG and five of seven receiving high dose BCG are still in remission (12+ — 25+ weeks). All relapse patients failed to develop delayed hypersensitivity or primary antibody response to the primary antigen Keyhole limpet hemocyanin (KLH). In contrast, remission patients all developed delayed hypersensitivity and a majority developed primary antibody response to KLH. Lynphocyte blastogenic response to mitogens and antigens and quantitative immunoglobulin levels did not change significantly during BCG therapy and were similar in remission and relapse patients. Eight weeks after starting therapy, the degree of skin test reactivity to established antigens was significantly greater in patients receiving high-dose BCG compared to patients receiving low dose BCG or relapse patients. Our study suggests that high-dose BCG may be associated with a heightened immune reactivity compared with low-dose BCG. Further follow-up is needed for conclusions regarding clinical benefit from immunostimulation with live BCG.