Approaches to the treatment of Philadelphia-positive acute lymphoblastic leukemia

Philadelphia positivity occurs in 20-25% of adult patients with ALL, the incidence increasing with age. 'Lymphoid-type' and 'stem cell-type' subgroups have been identified. Conventional chemotherapy is ineffective in eradicating the disease in the vast majority of patients. Allogeneic BMT is the only treatment currently available which offers a reasonable prospect of cure, with a 2 year actuarial survival of approximately 40% reported for patients transplanted in first remission or after relapse. In the absence of a histocompatible sibling, BMT from an unrelated donor early in first remission may be justified in young patients with 'lymphoid-type' disease which is characterised by a high rate of early relapse. The efficacy of ABMT in unproven; if used, purging should be considered as most harvested marrows have molecular evidence of residual disease. In the absence of BMT, experimental strategies such as therapy with cytokines to enhance differentiation of leukaemic blasts and maintenance interferon early after the attainment of CR should be considered.