Non-myeloablative conditioning with allogeneic hematopoietic cell transplantation for the treatment of high-risk acute lymphoblastic leukemia.
ABSTRACT Allogeneic hematopoietic cell transplantation is a potentially curative treatment for patients with acute lymphoblastic leukemia. However, the majority of older adults with acute lymphoblastic leukemia are not candidates for myeloablative conditioning regimens. A non-myeloablative preparative regimen is a reasonable treatment option for this group. We sought to determine the outcome of non-myeloablative conditioning and allogeneic transplantation in patients with high-risk acute lymphoblastic leukemia.
Fifty-one patients (median age 56 years) underwent allogeneic hematopoietic cell transplantation from sibling or unrelated donors after fludarabine and 2 Gray total body irradiation. Twenty-five patients had Philadelphia chromosome-positive acute lymphoblastic leukemia. Eighteen of these patients received post-grafting imatinib.
With a median follow-up of 43 months, the 3-year overall survival was 34%. The 3-year relapse/progression and non-relapse mortality rates were 40% and 28%, respectively. The cumulative incidences of grades II and III-IV acute graft-versus-host disease were 53% and 6%, respectively. The cumulative incidence of chronic graft-versus-host disease was 44%. Hematopoietic cell transplantation in first complete remission and post-grafting imatinib were associated with improved survival (P=0.005 and P=0.03, respectively). Three-year overall survival rates for patients with Philadelphia-negative acute lymphoblastic leukemia in first remission and beyond first remission were 52% and 8%, respectively. For patients with Philadelphia chromosome-positive acute lymphoblastic leukemia in first remission who received post-grafting imatinib, the 3-year overall survival rate was 62%; for the subgroup without evidence of minimal residual disease at transplantation, the overall survival was 73%.
For patients with high-risk acute lymphoblastic leukemia in first complete remission, non-myeloablative conditioning and allogeneic hematopoietic cell transplantation, with post-grafting imatinib for Philadelphia chromosome-positive disease, can result in favorable long-term survival.
- SourceAvailable from: Werner Linkesch
Article: Impact of minimal residual disease on outcomes after umbilical cord blood transplantation for adults with Philadelphia-positive acute lymphoblastic leukaemia: an analysis on behalf of Eurocord, Cord Blood Committee and the Acute Leukaemia working party of the European group for Blood and Marrow Transplantation.[Show abstract] [Hide abstract]
ABSTRACT: The status of umbilical cord blood transplantation (UCBT) in adults with Philadelphia-positive acute lymphoblastic leukaemia (Ph+ALL) and the impact of minimal residual disease (MRD) before transplant are not well established. We analysed 98 patients receiving UCBT for Ph+ALL in first (CR1) or second (CR2) complete remission (CR1, n = 79; CR2, n = 19) with MRD available before UCBT (92% analysed by reverse transcription polymerase chain reaction). Median age was 38 years and median follow-up was 36 months; 63% of patients received myeloablative conditioning and 42% received double-unit UCBT. Eighty-three patients were treated with at least one tyrosine kinase inhibitor before UCBT. MRD was negative (-) in 39 and positive (+) in 59 patients. Three-year cumulative incidence of relapse was 34%; 45% in MRD+ and 16% in MRD- patients (P =0·013). Three-year cumulative incidence of non-relapse mortality was 31%; it was increased in patients older than 35 years (P = 0·02). Leukaemia-free survival (LFS) at 3 years was 36%; 27% in MRD+ and 49% in MRD- patients (P = 0·05), and 41% for CR1 and 14% for CR2 (P = 0·008). Multivariate analysis identified only CR1 as being associated with improved LFS. In conclusion, MRD+ before UCBT is associated with increased relapse. Strategies to decrease relapse in UCBT recipients with Ph+ALL and MRD+ are needed.British Journal of Haematology 06/2014; · 4.96 Impact Factor
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ABSTRACT: Adult acute lymphoblastic leukemia (ALL) is a heterogeneous disease, due to the expression of different biological and clinical risk factors, for which allogeneic stem cell transplantation (alloHSCT) is an effective consolidation therapy. The non-relapse mortality of alloHSCT remains significantly higher compared with that of conventional chemotherapy. Therefore, one of the main challenges in the care of ALL is to establish a more precise prognostic definition to select patients who could take advantage from an alloHSCT. Currently, the use of minimal residual disease following induction and early consolidation therapy has improved the prognostic accuracy in defining ALL risk class. In Philadelphia-positive ALL, the introduction of tyrosine kinase inhibitors pre and post alloHSCT appears to improve outcomes significantly and, in the absence of specially designed clinical trials, alloHSCT remains the most effective post-remission therapy. Nowadays, alloHSCT can be performed according to various modalities encompassing the use of different conditioning regimens, as well as distinct donors and stem cell source, with a significant accessibility to transplant.Mediterranean Journal of Hematology and Infectious Diseases 01/2014; 6(1):e2014065.
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ABSTRACT: An essential component of allogeneic and autologous hematopoietic cell transplantation (HCT) is the conditioning regimen administered before the hematopoietic cell infusion. Early regimens relied on dose intensity, assuming that high-dose chemoradiotherapy would eliminate malignant disease and reinfusion of the graft would then restore hematopoiesis. However, as the contribution of graft-versus-tumor (GVT) effects to the success of allogeneic HCT was recognized over time, in an effort to exploit these, many investigators lowered the dose of radiation and chemotherapeutic agents in the preparative regimen. This resulted in a major paradigm shift, and, consequently, the pool of eligible patients underwent a remarkable expansion. In this article we provide a review of the definition of high-dose, reduced-intensity, and nonmyeloablative conditioning regimens, the most commonly used agents and combinations, and the evolution of some early regimens. We also provide a brief review of the toxicities associated with these regimens.Blood 06/2014; · 9.78 Impact Factor
Nonmyeloablative conditioning with allogeneic hematopoietic cell
transplantation for the treatment of high risk acute lymphoblastic
by Ron Ram, Rainer Storb, Brenda M. Sandmaier, David G. Maloney,
Ann E. Woolfrey, Mary Evelyn D. Flowers, Michael B. Maris, Gina G. Laport,
Thomas R. Chauncey, Thoralf Lange, Amelia A. Langston, Barry E. Storer,
and George Earl Georges
Haematologica 2011 [Epub ahead of print]
Citation: Ram R, Storb R, Sandmaier BM, Maloney DG, Woolfrey AE, Flowers ME,
Maris MB, Laport GG, Chauncey TR, Lange T, Langston AA, Storer BE, and Georges GE.
Nonmyeloablative conditioning with allogeneic hematopoietic cell transplantation for the
treatment of high risk acute lymphoblastic leukemia. Haematologica. 2011; 96:xxx
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Published Ahead of Print on April 20, 2011, as doi:10.3324/haematol.2011.040261.
Nonmyeloablative conditioning with allogeneic hematopoietic cell transplantation for the
treatment of high risk acute lymphoblastic leukemia
Short title: Nonmyeloablative transplantation for ALL patients
Ron Ram,1 Rainer Storb,1,2 Brenda M. Sandmaier,1,2 David G. Maloney,1,2 Ann Woolfrey,1,2
Mary E. D. Flowers,1,2 Michael B. Maris, 3 Ginna G. Laport,4 Thomas R. Chauncey,2,5
Thoralf Lange,6 Amelia A. Langston, 7 Barry Storer, 1,2 and George E. Georges1,2
1Fred Hutchinson Cancer Research Center, Seattle, WA, USA; 2University of Washington
School of Medicine, Seattle, WA, USA; 3Rocky Mountain Cancer Center, Denver, CO, USA;
4Stanford University, Stanford, CA, USA; 5Veterans Affairs Puget Sound Health Care System,
Seattle, WA, USA; 6University of Leipzig, Leipzig, Germany, and 7Emory University, Atlanta,
The work was supported by grants from the National Institutes of Health, Bethesda, MD, USA
(grants P01CA018029, P01CA078902, and P30CA015704). RR was a recipient of a fellowship
award from the Davidoff Foundation.
George E. Georges, M.D., Fred Hutchinson Cancer Research Center, 1100 Fairview Ave N,
D1-100; Seattle, WA 98109 USA. Phone: international +206.6676886.
Fax: international +206.6676124. E-mail: firstname.lastname@example.org
We thank the research nurses Michelle Bouvier and Hsien-Tzu Chen and data manager Gresford
Thomas for their invaluable help in this study; Helen Crawford, Bonnie Larson, and Sue
Carbonneau for manuscript preparation; and especially the patients and their families, the
transplantation teams, physicians, nurses, long-term follow-up team and support personnel for
their dedicated care of patients on this study.
Background. Allogeneic hematopoietic cell transplantation is a potentially curative treatment for
patients with acute lymphoblastic leukemia. However, the majority of older adults with acute
lymphoblastic leukemia are not candidates for myeloablative conditioning regimens. A
nonmyeloablative preparative regimen is a reasonable treatment option for this group. We sought
to determine the outcome of nonmyeloablative conditioning and allogeneic transplantation in
patients with high-risk acute lymphoblastic leukemia.
Design and Methods. Fifty-one patients, median age 56 years, underwent allogeneic
hematopoietic cell transplantation from sibling or unrelated donors after fludarabine and 2 Gray
total body irradiation. Twenty-five patients had Philadelphia chromosome-positive acute
lymphoblastic leukemia. Eighteen of these patients received post-grafting imatinib.
Results. With median follow-up of 43 months, the 3-year overall survival was 34%. The 3-year
relapse/progression and non-relapse mortality rates were 40% and 28%, respectively. The
cumulative incidences of grades II and III-IV acute graft-versus-host disease were 53% and 6%,
respectively. The cumulative incidence of chronic graft-versus-host disease was 44%.
Hematopoietic cell transplantation in first complete remission and post-grafting imatinib were
associated with improved survival, p=0.005 and 0.03, respectively. Three-year overall survival
for patients with Philadelphia-negative acute lymphoblastic leukemia in first remission and
beyond first remission were 52% and 8%, respectively. For patients with Philadelphia
chromosome-positive acute lymphoblastic leukemia in first remission who received post-grafting
imatinib, the 3-year overall survival was 62%; for the subgroup without evidence of minimal
residual disease at transplantation, the overall survival was 73%.
Conclusions. For patients with high-risk acute lymphoblastic leukemia in first complete
remission, nonmyeloablative conditioning and allogeneic hematopoietic cell transplantation, with
post-grafting imatinib for Philadelphia chromosome-positive disease, can result in favorable
Trial Registration: Clinicaltrials.gov identifier: NCT0036738
Key words: acute lymphoblastic leukemia, Philadelphia chromosome-positive, allogeneic
hematopoietic cell transplantation, nonmyeloablative conditioning, imatinib
Allogeneic hematopoietic cell transplantation (HCT) with a myeloablative conditioning
regimen is an established potentially curative treatment for patients with high-risk acute
lymphoblastic leukemia (ALL).1,2 However, many older adults with ALL are not candidates for
high dose conditioning and HCT.3,4 The use of nonmyeloablative conditioning with fludarabine
and low dose total body irradiation (TBI) can substantially decrease the toxicity of the
preparative regimen and extends allogeneic HCT to older or medically infirm patients.5,6 This
approach relies primarily on potent graft-versus-leukemia effects to prevent relapse of the
disease. Other reduced intensity regimens have been reported by investigators for the treatment
of patients with ALL.3,7-9 However, relapse has remained a major problem following reduced
intensity conditioning regimens.
In recent years, the development of imatinib mesylate, and subsequently the newer tyrosine
kinase inhibitors (TKIs), dasatinib and nilotinib, combined with chemotherapy were very
effective for inducing disease remission in patients with Philadelphia chromosome positive (Ph+)
ALL.10-13 Imatinib therapy after allogeneic HCT was well tolerated and improved relapse-free
survival following myeloablative conditioning compared to historical controls not given imatinib
therapy after HCT.14 A recent report showed that patients with Ph+ ALL who received induction
chemotherapy with imatinib followed by myeloablative conditioning and allogeneic HCT for
Ph+ ALL in CR1 had superior overall survival compared to patients who did not undergo HCT.15
We report on the multicenter experience with allogeneic HCT following nonmyeloablative
conditioning with fludarabine and 2 Gray (Gy) TBI for patients with high-risk ALL. We identify
risk factors for disease relapse and mortality. We also describe the causes of non-relapse
mortality (NRM) and the toxicity and efficacy of post-HCT imatinib for patients with Ph+ ALL.
DESIGN AND METHODS
This analysis includes 51 consecutive patients with ALL who were prospectively enrolled
and received non-myeloablative conditioning followed by allogeneic HCT on sequential multi-
institutional protocols between February 1, 2000 and July 30, 2009. The protocols were
registered as National Cancer Institute clinical trials. Patients treated with post-grafting imatinib
were registered on NCT00036738. Other patients were enrolled in sequential protocols specific
for donor type and minor variations in planned duration of post-grafting immunosuppression.
Patients were treated at 6 centers with the Fred Hutchinson Cancer Research Center (FHCRC),
Seattle, WA, acting as the coordinating center. All patients signed informed consent forms
approved by the local institutional review boards.
Patients with related or unrelated donors (URD) were eligible for nonmyeloablative
conditioning if they were older than 55 or 50 years, respectively. Younger patients were eligible
if they had high risk ALL and co-morbid conditions that excluded them from myeloablative
conditioning or if they had disease relapse after a preceding myeloablative HCT. Adult high risk
ALL was defined as greater than first complete remission (CR1), or CR1 and at least one of the
following: (1) age > 35 years, (2) white blood cells (WBC) > 30,000/µL at diagnosis for B cell
ALL or WBC >100,000/µL at diagnosis for T cell ALL or (3) Ph+ ALL with t(9;22).2 Pediatric
high risk ALL was defined as >CR1, or CR1 and the addition one of the following: (1) failure to
achieve complete remission after induction phase; (2) t(9;22) or t(4;11) clonal abnormalities; and
(3) poor response to prednisone in T cell ALL with WBC > 100,000/µL.16
Patients referred for HCT in CR1 had a median of 3 cycles (range, 3-4) of various standard
induction/intensification chemotherapy regimens.17-19 Pre-transplant disease status was assessed
within 21 days before HCT. CR was defined according to standard morphologic criteria as
outlined in the International Working Group.20 For patients in CR, minimal residual disease
(MRD) was assessed by multiparametric flow cytometry (minimum 4-color, cut-off level to
establish MRD positivity ≥ 0.01%), karyotype analysis (G-banding) and fluorescence in situ
hybridization (FISH). Quantitative reverse transcriptase–polymerase chain reaction (RT-PCR) of
p210 and p190 BCR/ABL mRNA was not part of the MRD workup in all of the patients with Ph+
ALL; thus, PCR results were not included in assessment of MRD. All patients and donors had
high resolution HLA-allele level typing performed for 10 HLA alleles (HLA-A, B, C, DRB1 and
DQB1). Patients received grafts from the following donors: HLA identical sibling (n=9), 10/10
HLA-allele matched URD (n=31), single HLA allele mismatched URD (n=6) and single HLA-
antigen mismatched URD (n=5). Pretransplant comorbidities were assessed retrospectively,
using the HCT comorbidity index (HCT-CI).21
Regimen and treatment plan
The conditioning regimen consisted of fludarabine (30 mg/m2/day on days -4 through -2
before HCT and 2 Gray (Gy) TBI given at 0.07 to 0.1 Gy/min from linear accelerator sources on
day 0.6 Patients received unmanipulated G-CSF mobilized peripheral blood stem cells (PBSC)
shortly after TBI. One patient received an unrelated bone marrow graft instead of PBSC. Post-
grafting immunosuppression consisted of combined mycophenolate mofetil and a calcineurin
inhibitor, cyclosporine or tacrolimus, as previously described.5,22-25
All patients received intrathecal methotrexate (12 mg/dose or 6 mg/dose if given via
Ommaya reservoir) for central nervous system (CNS) prophylaxis, two doses pre-transplant
(once per week) and six doses post-transplant (starting at day +30, once every 2 weeks). All men
received 16 Gy in 8 fractions of testicular irradiation during conditioning. All patients with a
history of CNS disease, 3 with Ph– and 4 with Ph+ ALL, received cranio-spinal irradiation as
part of the conditioning regimen.
The mean infused PBSC dose was 8.5×106 CD34/kg cells (range, 0.9-24.4). Engraftment
and donor chimerism were measured by variable number tandem repeat (VNTR) of
microsatellite markers at days 28, 56 and 84 after HCT.
Acute and chronic graft-versus-host disease (GVHD) were assessed as described.6,26
Toxicities occurring within the first 100 days were scored using the Common Terminology
Criteria for Adverse Events v3.0. Disease response after HCT was monitored with standard
marrow morphology, flow cytometry and conventional cytogenetics, FISH and, if indicated,
PCR for BCR-ABL transcripts.27 Disease responses were assessed at 1, 3, 6, 12 and 24 months
after HCT and/or as clinically indicated.
Ph+ ALL patients
Twenty-five patients had the Ph+ cytogenetic abnormality detected at diagnosis. After the
introduction of imatinib, 18 patients enrolled in a study evaluating the safety and efficacy of
incorporating post-grafting imatinib to the treatment regimen. Patients were initiated on imatinib
at a dose of 600 mg orally once daily either by their referring physician or at the transplant center
before enrollment on the study. Imatinib was stopped on day –2 before HCT to avoid interaction
with engraftment of donor hematopoietic cells. Imatinib was reinitiated at 400-600 mg daily after
HCT when ANC was >500/µL or on day +15 if there was no neutropenia. Imatinib was
continued for at least one year after HCT, unless there was toxicity or disease progression; all
patients received at least 1 month of imatinib. Dose reduction of imatinib was allowed for
mitigation of side effects/ toxicities.
Causes of death
In patients who relapsed or progressed with ALL, relapse/progression was listed as the primary
cause of death regardless of other associated events. Relapse was defined as recurrence of
malignancy based on one or more of the following parameters: marrow morphology, flow
cytometry, cytogenetic studies, including FISH, or RT-PCR for BCR/ABL transcripts. All deaths
occurring in the absence of relapse/progression were considered NRM.
Data were analyzed as of October 1, 2010. Overall survival (OS) was estimated using the
Kaplan-Meier method. Cumulative incidence estimates were calculated for acute and chronic
GVHD, relapse and NRM. Death was treated as a competing risk in the analyses of
relapse/progression and acute and chronic GVHD. Relapse/progression was treated as a
competing risk when analyzing NRM. Cox regression was used for univariate analyses of risk
factors for all time-to-event end points. For each analysis, hazard ratios (HR) and 95%
confidence intervals (95% CI) are given together with p values for comparisons with the
reference category. All p values are derived from likelihood ratio statistics and are two sided.
Fifty one patients underwent allogeneic HCT. All had high risk ALL including 19 who were
beyond CR1. Six patients were under 18 years of age (1 CR1 and 5 >CR1). Table 1 summarizes
the patients' characteristics. Twenty-five patients had Ph+ ALL. Of these, 18 received post-
grafting imatinib (Table 2). The median follow-up for surviving patients was 43 (range, 14-98)
Fifty patients achieved sustained donor engraftment. One patient with Ph+ ALL had non-
fatal primary graft rejection. This patient received an HLA matched unrelated marrow graft with
a 0.9×106/kg CD34+ cell dose. After graft rejection, this patient was treated with imatinib, chose
not to undergo a second HCT, relapsed and died 20 months after HCT. The median donor CD3+
T-cell chimerism levels for the 50 PBSC recipients at day 28 and day 84 were 79 (range, 15-
100)% and 88 (range, 48-100)%, respectively. The chimerism and engraftment patterns were not
different in patients treated with imatinib.
By day 120 after HCT, 53% of patients developed grade II acute GVHD and 6% developed
grades III-IV acute GVHD (Figure 1A). Among the patients who received HLA-identical sibling,
HLA-allele-matched unrelated donor, and HLA-allele/antigen mismatched unrelated grafts, the
overall incidences of grade II-IV acute GVHD were 33%, 50% and 91%, respectively.
Cumulative incidence of chronic extensive GVHD at 3 years was 42% (Figure 1B).
Among the patients with Ph+ ALL treated with post-grafting imatinib (n=18), 10 (56%)
developed grade II-IV acute GVHD. There was no significant difference between the incidences
of acute GVHD among patients who received or did not receive imatinib (HR=0.65, 95% CI 0.3-
1.4, p=0.25). Ten of the 18 patients (56%) developed chronic extensive GVHD and 5 (28%)
developed limited chronic GVHD. There was no significant difference in the incidence of
chronic GVHD among patients who received or did not receive imatinib (HR=1.4, 95% CI 0.6-
3.3, p=0.45). Five patients (36%) developed chronic skin GVHD while receiving imatinib
treatment. Discontinuation of imatinib after HCT was not associated with new onset or
exacerbation of chronic GVHD.
NRM at 3 years after HCT among all patients was 28% (Figure 1C). The following causes
were included under NRM: GVHD (n=4), GVHD-associated infections (n=8), sepsis (n=1),
congestive heart failure (n=1) and suicide (n=1). There was no significant difference in NRM
among patients who were or were not treated with post-HCT imatinib (HR=0.5, 95% CI 0.2-1.5,
p=0.20), respectively. The four deaths in the imatinib group were due to GVHD-associated
infections: bacterial pneumonia, sepsis with pancreatitis, respiratory syncytial virus pneumonia
and community acquired H1N1 viral pneumonia.
Disease relapse/ progression
Among the 51 patients, 22 (43%) had relapse/progression at a median of 5 (range, 0.3 to 58)
months after HCT. None of the patients developed isolated CNS relapse. None were treated with
donor lymphocyte infusion for disease relapse. The median time from the diagnosis of relapse to
death was 4 (range, 0.3-15) months in the 20 patients that had died at the time of analysis.
Overall, the 3-year estimated probability of relapse/progression was 40%. Univariate
analysis identified risk factors for relapse/progression (Table 3). Patients >CR1 at the time of
HCT had a significantly increased risk for relapse after HCT compared to those in CR1 (HR=3.9,
95% CI 1.6-9.5, p=0.002). For Ph– ALL (n=26), the 3-year estimated relapse rate for CR1 and
>CR1 patients was 15% and 62%, respectively (Figure 2). For Ph+ ALL (n=25), the 3-year
estimated relapse rate for CR1 and >CR1 was 32% and 67%, respectively (Figure 2). Two
patients with molecular evidence of disease after transplant were included as disease relapse. For
patients with Ph+ ALL, evidence of additional cytogenetic abnormalities at diagnosis was
borderline associated with an increased risk of relapse after HCT (HR=3.4, 95% CI 0.9-13,
The estimated 3-year OS among the 51 patients was 34%. Relapse was the primary cause of
death (n=20, 57% of all deaths). Univariate analysis performed for the entire cohort identified
>CR1 disease status as the only significant factor associated with increased mortality (HR=2.7,
95% CI 1.4-5.3, p=0.005), Table 3. Other factors (donor source, acute or chronic GVHD) were
not significantly associated with increased mortality. The 3-year OS for patients with Ph– ALL
in CR1 and >CR1 were 52% and 8%, respectively, (HR=3.4, 95% CI 1.3-9.1, p=0.01) (Figure
3A). Excluding the six pediatric patients, the 3-year OS for CR1 and >CR1 were 48% and 0%,
respectively (HR=4.5, 95% CI 1.4-15.1, p=0.01).
Among patients with Ph+ ALL, treatment with post-HCT imatinib was associated with
significantly decreased mortality (HR=0.3, 95% CI 0.1-0.9, p=0.03), Table 3. The 3-year OS for
patients with Ph+ ALL who were in CR1 vs. >CR1 were 47% and 17%, respectively; however,
this difference did not reach statistical significance (HR=1.8, 95% CI 0.6-5.4, p=0.32). For
patients in CR1 who received post-grafting imatinib, 3-year OS was 62% (Figure 3B, Table 2);
for the subgroup that had no evidence of MRD at HCT, the OS was 73%. Additional cytogenetic
abnormalities (beyond Ph+) detected at diagnosis, showed a trend for increased mortality
(HR=2.0, 95% CI 0.7-5.5, p=0.19).
Outcomes of patients age <18 years
Six patients with Ph– ALL were younger than 18 years at the time of HCT with a median
age of 11 (range, 8-16) years (4 had relapsed after a prior allograft, 1 CR1 and 1 CR3). Two
patients received HLA-antigen mismatched unrelated grafts. All 5 patients >CR1 relapsed (3 of
them within 6 months). All patients developed acute GVHD. The single CR1 patient is currently
alive at 88 months post HCT.
Outcomes of patients age >60 years
Sixteen patients (31%) were older than 60 years at the time of HCT with a median age of 63
(range, 61-69) years. Six of the 16 (38%) died from non-relapse causes and 4 (25%) had disease
relapse. Of the 9 patients with Ph– ALL, 2 in CR1 are currently alive for >2.1 years. Among
patients with Ph+ ALL (n=7), the estimated 3-year OS was 57%.
The median duration of post-HCT imatinib treatment was 11.5 (range, 3-50) months (Table
2). The drug was given at a daily dose range of 200-600 mg. In three patients dose modifications
were made. In general, imatinib was well tolerated. Three patients (17%) discontinued imatinib
because of adverse events, and all events were reversible (two gastrointestinal toxicities and one
recurrent pleural effusion).
Despite improvements in therapy, mortality from high-risk ALL has not substantially
decreased in older patients. Two large prospective trials and meta-analyses summarizing the
results of the previous controlled trials showed that allogeneic HCT after myeloablative
conditioning improved the outcome of adult patients with high risk ALL.2,28-31 However, in
patients with high risk disease, survival advantage was demonstrated only up to age 35 years.2,32
Developing HCT approaches for older or medically infirm patients with ALL has remained
challenging. While the outcome for patients not undergoing allogeneic HCT is very poor, those
who proceed with myeloablative conditioning followed by HCT have an unacceptably high
NRM.2,33 This multicenter study addressed the problem of NRM in older and medically infirm
patients by using a nonmyeloablative conditioning regimen consisting of fludarabine and 2 Gy
TBI which depended on allogeneic graft-vs.-leukemia effects for cure of high risk ALL.
We observed that OS was significantly improved for patients who underwent HCT early in
the course of their disease. For Ph– ALL patients in CR1, 3-year OS was 52%, while for patients
beyond CR1, 3-year OS was only 8%, primarily due to increased disease relapse. Other