autologous blood and marrow transplantation - Blog Science ...

Donor Lymphocyte Infusions Produce Durable
Molecular Remission in Patients Who Relapse
After Allografting for CML in Chronic Phase:
The Consequent Need to Reassess
the Definition of Leukemia-Free Survival
C. Craddock, F. Dazzi, R.M. Szydlo, E. Olavarria, N.C.P.
F. van Rhee, E. Kanfer, J.F. Apperley, J.M. Goldma
ICSM Haematology Department, Hammersmith Hospital, London, U.K.
The options for treating patients who relapse after allogeneic hematopoietic
stem cell transplantation (SCT) for chronic myeloid leukemia (CML) include a
second allograft, administration of interferon-alpha, and infusion of lymphocytes
from the original donor. A substantial proportion of patients will achieve molecular
remission after donor lymphocyte infusions (DLI), but the durability of these
remissions and therefore the contribution of DLI to management of patients who
relapse is not yet established. We studied a cohort of 247 patients with CML in
chronic phase who received an allogeneic SCT from an HLA-identical sibling
donor (n=147) or a volunteer unrelated donor (n=100) during the period 1 January
1986 to 31 December 1995 with a minimum follow up of 27 months. During the
period of observation, 74 patients relapsed, and of these, 52 received DLI. Twentyeight
patients were treated with a single ("bulk") infusion of donor lymphocytes,
and 24 received donor lymphocytes on an escalating dose schedule. Twenty-seven
(52%) patients achieved a complete molecular remission. No patient who achieved
a molecular remission has relapsed, with a median follow-up of 21 months (range
4-77). Because conventional measures of leukemia-free survival (LFS) censor
patients at the time of relapse and take no account of any subsequent remission that
may prove durable, we have established a new category of LFS, termed current
LFS (CLFS), which is defined as survival without molecular evidence of relapse at
the time of most recent assessment. For the 247 patients in this study, the conventionally
defined LFS at 5 years was 33% (95% CI 24-39%), while the CLFS was
45% (95% CI 39-52%). These data show that the molecular remissions that can be
achieved in CML patients who receive DLI for relapse after allografting may
continue for some years.
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