Species-specific therapy of acute lymphoid leukemia.

In the past 10 years immunophenotyping of ALL has been demonstrated to be useful for selecting and scheduling chemotherapy. Different drug regimens are now used for T-cell and B-cell ALL than for non-T non-B ALL with the result that survival and cure of T-cell and B-cell ALL have been considerably improved. The use of different drug regimens for different immunophenotypic varieties of non-T non-B ALL is being tested. "Prognostic factors" of ALL are artifacts of data analysis and treatment and should no longer be used for guiding treatment. The administration of all-inclusive multiple-drug therapy to all patients with ALL regardless of species should also be abandoned. Minimally effective drugs can interfere with dosage and continuity of more effective drugs, and can result in side effects and sequelae that increase the mortality and morbidity of treatment. Since acute leukemias are genetic disorders of hematopoiesis the future direction of leukemic therapy is toward genetic targeting.