Ten-year follow-up of a single center prospective trial of unmanipulated peripheral blood stem cell autograft and interferon-alpha in early phase chronic myeloyd leukemia.

BACKGROUND AND OBJECTIVES: The potential role of autologous stem cell transplantation (ASCT) as an alternative therapeutic strategy in chronic myelogenous leukemia (CML) has been widely explored in pilot studies, but the clinical results in terms of survival have so far been evaluated only retrospectively and in heterogeneous groups of patients. The goal of our prospective study was to evaluate the feasibility and long-term efficacy of unmanipulated ASCT followed by low-dose interferon-alpha in a homogeneous group of patients affected by CML in a very early phase of disease. DESIGN AND METHODS: Twenty-six unselected consecutive patients with CML in chronic phase underwent stem cell collection at diagnosis, then received cytoreductive treatment with hydroxyurea and, subsequently, a busulphan-melphalan myeloablative regimen followed by unmanipulated stem cell graft within one year of diagnosis. Interferon was given a median of 6.5 months after transplant at escalating doses, starting from 0.5 x 10(6) IU 3 times/week, on the basis of the clinical and hematologic tolerance.
RESULTS: Median chronic phase duration from diagnosis is 9 years. The ten-year projected probability of overall survival from diagnosis is 55% with a median follow-up of surviving patients of 9.5 years (8-10.5); median survival has not been reached after ten years. INTERPRETATION AND
CONCLUSIONS: Our experience suggests that high-dose therapy followed by unmanipulated peripheral blood stem cell transplantation and low-dose interferon-alpha is a feasible approach, which results in long-term survival in newly diagnosed CML patients. These data need to be confirmed in controlled trials comparing ASCT with other therapeutic approaches, such as the use of interferon-alpha alone or in combination with other agents.