A chlorinated heterocyclic sulfanilamide with potential antineoplastic activity and potential immunosuppressive activity. Chloroquinoxaline sulfonamide poisons topoisomerase II alpha and topoisomerase II beta, thereby causing double-stranded breaks in DNA, accumulation of unrepaired DNA, and apoptosis. This agent also exhibits lymphotoxicity by inhibiting lymphocyte activation in a cell cycle-specific manner.