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autologous blood and marrow transplantation - Blog Science ...

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Heslop et al. 517<br />

Disease Free Survival<br />

Months post BMT<br />

Figure 1. Leukemia-free survival in patients with AML receiving autografts. Leukemia-fr<br />

survival was estimated using the log-rank test <strong>and</strong> Kaplan Meier plots. Patients with AML<br />

first remission who received an autoBMT with marked <strong>marrow</strong> were compared with cont<br />

porary control patients who received unmanipulated <strong>marrow</strong> after the same chemother<br />

<strong>and</strong> transplant regimen. There is no significant difference in leukemia-free survival betw<br />

recipients of marked <strong>marrow</strong> (59% at 3 years) <strong>and</strong> unmarked <strong>marrow</strong> (39% at 3 years).<br />

years for the patients who received marked <strong>marrow</strong> <strong>and</strong> 54% for the patients who<br />

received unmarked <strong>marrow</strong>. Similarly, the cumulative incidence of relapse is not<br />

significantly different between recipients of marked <strong>marrow</strong> (30% at 3 years) <strong>and</strong><br />

unmarked <strong>marrow</strong> (59% at 3 years) (P=0.06).<br />

DISCUSSION<br />

Transfer of marker genes to <strong>autologous</strong> <strong>marrow</strong> has shown that residual<br />

malignant cells contaminating the product may be one source of subsequent<br />

leukemic relapse in patients with AML. A similar result was seen in a study of adult<br />

1 5<br />

patients with CML, in which marked cells coexpressing bcr-abl <strong>and</strong> neo were<br />

found at the time of relapse. Marked malignant cells were not found in adult<br />

patients relapsing after autograft for AML or acute lymphoid leukemia (ALL). 16<br />

However, only -10% of the <strong>marrow</strong> was marked in that study, <strong>and</strong> gene transfer to<br />

normal cells was very low.<br />

There are no data yet in the second-generation study on the efficacy of purging.<br />

A potential problem with this approach is that only a positive result is definitive.<br />

Hence, a relapse with marked leukemic cells indicates that the purging technique<br />

employed does not eradicate all leukemic cells. However, a negative result may<br />

reflect either a low number of residual leukemic cells in <strong>marrow</strong>, which were not<br />

marked, or a relatively small contribution to relapse from the infused <strong>marrow</strong> as

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