Unrelated donor bone marrow transplantation therapy for chronic myelogenous leukemia

Eight patients received allogeneic bone marrow transplantation (BMT) as therapy for chronic myelogenous leukemia (CML) using marrow from unrelated donors. In all cases donors and recipients were HLA DR identical and had low MLC reactivity. In three cases recipients received marrow that was identical at the HLA A,B loci. In five cases HLA identity differed for one HLA A locus antigen. The unrelated donor search interval ranged from 2 to 28 months (median, 3 months). All recipients were prepared with a combination of cyclophosphamide, 60 mg/kg/d administered intravenously (IV) (days -6,-5) and with total body irradiation administered in 165 cGy fractions twice daily for four days (days -4, -3, -2, -1). Engraftment occurred in all cases (range, 18 to 48 days; median, 35 days), and return to a complete Philadelphia chromosome (Ph') negative state was documented in six of eight cases. Moderate or severe acute graft v host disease (GVHD) occurred in seven of eight cases, and extensive chronic GVHD in four of six evaluable recipients. A B cell lymphoproliferative disorder developed in one patient. Four recipients have died within 2 to 4 months of transplant. Four of eight patients survive at 11+ to 24+ months following transplantation (median, 15+ months) with normal peripheral blood counts and without evidence of leukemia. Current Karnofsky activity assessments are 90% or 100% in all survivors. Curative therapy of CML has been available only to the minority of patients eligible for sibling donor BMT. Unrelated donor BMT can be effective in the treatment of CML and may be particularly useful in this disorder since the prolonged stable phase of disease offers an opportunity to locate suitable donors.