3 . 0 Background 
3 . 1 Treatment of Chronic Myelogenous Leukemia 
Allogeneic Marrow Transplantation in CML 
Chronic myelocytic leukemia (CML) is a disease 
affecting primarily adults between the ages of 30 and 65. 
with a maximum incidence at approximately 45 years. 
Allogeneic bone marrow transplantation cures over 50% of 
patients who manifest the early chronic phase of disease 
( CML-CP) . 7 The prospect for cure in advanced disease is 
poor. In the accelerated and blast phases long-term survival 
is achieved in only 10-25% of patients. 8 In most centers 
allogeneic marrow transplantation is limited to patients who 
are under the age of 50. Complications associated with 
increased mortality, such as acute and chronic graft versus 
host disease, are more frequent in older patients. 9 
Considering these factors allogeneic transplantation is 
recommended early in the chronic phase of the disease in 
patients of a suitable age if a compatible related donor is 
identified. 
Since only 25-35% of patients with CML have a matched 
sibling donor suitable for transplant, marrow registries 
including the National Marrow Donor Program have been 
established with over 400,000 potential donors available for 
patients who lack a related donor. 10 In one 
multi-institutional series of patients with CML-CP 
transplanted with matched, unrelated marrow grafts, survival 
appeared somewhat inferior compared to patients transplanted 
from fully matched sibling donors. 11 Lower survival rates 
also have been described with unrelated donors in the 
National Marrow Donor Program (N. Kernan, personal 
communication) . Long term disease-free survival is 
achievable with unrelated marrow transplantation, although 
the risk of acute mortality related to graft vs. host 
disease is substantial. Unfortunately, only 30-35% of 
patients who lack a matched sibling donor can find a 
compatible donor through the registry. 12 
With over 50-70% of patients with CML unable to undergo 
allogeneic marrow transplantation, new strategies must be 
developed to improve survival and provide the potential for 
cure. 
Interferon to Suppress Ph+ Cells in CML: 
Alpha interferons are naturally occurring polypeptides 
with properties including antiviral, immunomodulatory, and 
growth-regulatory activities. The activity of alpha 
interferon in hematologic diseases such as CML has been 
established. 13,14 In 96 previously treated and untreated 
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