Drug-induced antibodies during 2-N-methyl-9-hydroxyellepticinium acetate (NSC-264137) treatment: Schedule dependency and relationship to hemolysis

Drug-dependent antibodies were investigated in patients treated with elleptinium acetate, a cytostatic drug with activity in advanced breast cancer. Retrospective analysis of 83 patients, receiving weekly intravenous elliptinium, showed a high incidence of anti-elliptinium antibodies (20%). Hemolysis occurred among antibody-positive patients, apparently related to the antibody titer. The predictability of anti-elliptinium antibodies for hemolysis and the schedule dependency of antibody development was examined prospectively. Among 42 patients treated weekly for at least three courses, 40% developed antibodies. Of 30 patients receiving elliptinium daily for three days every three weeks, none developed either antibodies or hemolysis. Only antibody positive patients, with titers ≥ 32 were at risk for hemolysis. The possible mechanisms are discussed.