Analysis of the role of hematopoietic stem-cell transplantation in infants with acute lymphoblastic leukemia in first remission and MLL gene rearrangements: a report from the Children's Oncology Group

PURPOSE

Although the majority of children with acute lymphoblastic leukemia (ALL) are cured with current therapy, the event-free survival (EFS) of infants with ALL, particularly those with mixed lineage leukemia (MLL) gene rearrangements, is only 30% to 40%. Relapse has been the major source of treatment failure for these patients. The parallel Children's Cancer Group (CCG) 1953 and Pediatric Oncology Group (POG) 9407 studies were designed to test the hypothesis that more intensive therapy, including dose intensification of chemotherapy, and hematopoietic stem-cell transplantation (HSCT) would improve the outcome for this group of patients.

PATIENTS AND METHODS

One hundred eighty-nine infants (CCG 1953, n = 115; POG 9407, n = 74) were enrolled between October 1996 and August 2000. For infants with the MLL gene rearrangement and an appropriate donor, HSCT was the preferred treatment on CCG 1953 and investigator option on POG 9407 after completion of the second phase of therapy. Fifty-three infants underwent HSCT.

RESULTS

The 5-year EFS rate was 48.8% (95% CI, 33.9% to 63.7%) in patients who received HSCT and 48.7% (95% CI, 33.8% to 63.6%) in patients treated with chemotherapy alone (P = .60). Transplantation outcomes were not affected by the preparatory regimen or donor source.

CONCLUSION

Our data suggest that routine use of HSCT for infants with MLL-rearranged ALL is not indicated. However, limited by small numbers, this study should not be considered the definitive answer to this question.

Young adults with acute lymphoblastic leukemia have an excellent outcome with chemotherapy alone and benefit from intensive postinduction treatment: a report from the children's oncology group

PURPOSE

Patients 16 to 21 years of age with acute lymphoblastic leukemia (ALL) have an inferior outcome compared with younger children, leading some medical oncologists to advocate allogeneic stem-cell transplantation in first remission for these patients. We examined outcome for young adults with ALL enrolled onto the Children's Cancer Group (CCG) 1961 study between 1996 and 2002.

PATIENTS AND METHODS

CCG 1961 entered patients with ALL 1 to 21 years of age with initial WBC count > or = 50,000/microL and/or age > or = 10 years. Randomly assigned therapies evaluated the impact of postinduction treatment intensification on outcome. We examined outcome and prognostic factors for 262 young adults with ALL.

RESULTS

Five-year event-free and overall survival rates for young adult patients are 71.5% (SE, 3.6%) and 77.5% (SE, 3.3%), respectively. Rapid responder patients (< 25% bone marrow blasts on day 7) randomly assigned to augmented therapy had 5-year event-free survival of 81.8% (SE, 7%), as compared with 66.8% (SE, 6.7%) for patients receiving standard therapy (P = .07). One versus two interim maintenance and delayed intensification courses had no significant impact on event-free survival. WBC count more than 50,000/microL was an adverse prognostic factor.

CONCLUSION

Young adult patients with ALL showing a rapid response to induction chemotherapy benefit from early intensive postinduction therapy but do not benefit from a second interim maintenance and delayed intensification phase. Given the excellent outcome with this chemotherapy, there seems to be no role for the routine use of allogeneic stem-cell transplantation in first remission for young adults with ALL.

Outcome After Relapse Among Children With Standard-Risk Acute Lymphoblastic Leukemia: Children's Oncology Group Study CCG-1952

Purpose

The event-free survival (EFS) of children with standard-risk acute lymphoblastic leukemia (SR-ALL) is now more than 80%. However, prognosis after relapse continues to be poor. We examined postrelapse outcomes of children initially treated on the Children's Cancer Group CCG-1952 study.

Patients and Methods

We evaluated outcomes after bone marrow (BM) relapse and isolated extramedullary (EM) relapse for 347 patients with SR-ALL (WBC < 50,000/μL; age, 1 to 9 years). The prognostic significance of several factors for EFS after relapse (EFS2) was assessed by Cox regression analysis. Stem-cell transplant (SCT) was compared with chemotherapy as salvage treatment.

Results

The mean ± SE times to isolated central nervous system relapse, BM relapse, and isolated testicular relapse were 23 ± 1 months (range, 1 to 88 months), 36 ± 1 months (range, 2 to 79 months), and 40 ± 2 months (range, 16 to 64 months), respectively. The estimated percent ± SE 3-year EFS2 and overall survival rates after BM relapse were 37% ± 4% and 46% ± 4%, respectively, and rates after isolated EM relapse were 57% ± 5% and 71% ± 5%, respectively. By multivariate analysis, we found the duration of first remission to be the most significant predictor of EFS2 for either BM relapse or isolated EM relapse. Outcome was equivalent with SCT or chemotherapy after early or late relapse of SR-ALL at any site.

Conclusion

Duration of first remission remains the most significant predictor of outcome after either BM or isolated EM relapse of SR-ALL. Prognosis after early BM relapse remains poor and is not improved with SCT in this cohort.

Intravenous 6-mercaptopurine decreases salvage after relapse in childhood acute lymphoblastic leukemia: a report from the Children's Cancer Group study CCG 1922

PURPOSE

To compare outcomes of patients with NCI standard risk acute lymphoblastic leukemia (ALL) who relapsed after being randomized to receive either oral or intravenous 6-mercaptopurine (6MP) in the Children's Cancer Group study CCG 1922.

PATIENTS AND METHODS

CCG 1922 accrued patients from March 1993 to August 1995. A total of 1,060 patients were randomly assigned to four treatment groups: oral 6MP plus prednisone (OP), intravenous 6MP plus prednisone (IP), oral 6MP plus dexamethasone (OD), and intravenous 6MP plus dexamethasone (ID). During the 2nd through 4th month of therapy groups OP and OD were treated with 75 mg/m(2)/day of oral 6MP for 70 days and groups IP and ID with 1,000 mg/m(2)/week of intravenous 6MP over 10 hr for 11 doses. All patients received a single delayed intensification and all received oral 6MP in maintenance.

RESULTS

Patients randomized to oral 6MP had significantly better 5-year overall survival (96 +/- 1% vs. 92 +/- 1%; P = 0.008). There was, however, no statistically significant difference in the event-free survival (EFS). Of the 179 patients who relapsed, 84 had a second or later event and 68 have died. Forty of the 84 second events were a death. Survival after relapse was significantly greater for patients randomized to oral 6MP during consolidation than those receiving intravenous 6MP (P = 0.002, log rank test) with 4-year survival post-relapse of 67 +/- 6% vs. 48 +/- 6%. The steroid randomization had no influence on outcome. Post-relapse therapy details are not available and if different between groups may have influenced the outcome.

CONCLUSION

Treatment with intravenous 6MP during a brief period of total therapy had a significant negative impact on the prognosis in childhood ALL even though oral 6MP was used during maintenance.

Lymphoblast biology and outcome among children with Down syndrome and ALL treated on CCG-1952

BACKGROUND

Patients with Down syndrome (DS) and standard risk (SR) acute lymphoblastic leukemia (ALL-DS) are reported to have inferior event free (EFS) and overall survival (OS) compared to patients without DS (ALL-NDS).

PROCEDURE

We compared the prevalence of favorable and unfavorable clinical and biologic features, toxicity and outcome within the ALL-DS and ALL-NDS cohorts of 2,174 eligible patients with SR-ALL enrolled on CCG-1952.

RESULTS

Fifty-nine patients (3%) had ALL-DS. DS patients were less likely to have either favorable (hyperdiploidy, triple trisomy of chromosomes 4, 10, and 17, TEL-AML1 rearrangement) or unfavorable (T-cell ALL, hypodiploidy, adverse translocations) biologic features. Toxicity occurred significantly more often and number of days hospitalized was significantly greater in ALL-DS than in ALL-NDS. ALL-DS patients had an inferior 4-year EFS compared to the NDS cohort. However, EFS was equivalent when the comparison excluded ALL-NDS with favorable biologic features. OS was significantly inferior for ALL-DS.

CONCLUSIONS

The absence of favorable biologic features within ALL-DS contributes to the difference in EFS previously observed between DS and NDS SR-ALL cohorts.

Deletion of 7p or monosomy 7 in pediatric acute lymphoblastic leukemia is an adverse prognostic factor: a report from the Children's Cancer Group

Monosomy 7 or deletions of 7q are associated with many myeloid disorders; however, the significance of such abnormalities in childhood acute lymphoblastic leukemia (ALL) is unknown. Among 1880 children with ALL, 75 (4%) had losses involving chromosome 7, 16 (21%) with monosomy 7, 41 (55%) with losses of 7p (del(7p)), 16 (21%) with losses of 7q (del(7q)), and two (3%) with losses involving both arms. Patients with losses involving chromosome 7 were more likely to be > or =10 years old, National Cancer Institute (NCI) poor risk, and hypodiploid than patients lacking this abnormality. Patients with or without these abnormalities had similar early response to induction therapy. Event-free survival (EFS) and survival for patients with monosomy 7 (P<0.0001 and P=0.0007, respectively) or del(7p) (P<0.0001 and P=0.0001, respectively), but not of patients with del(7q), were significantly worse than those of patients lacking these abnormalities. The poorer EFS was maintained after adjustment for a Philadelphia (Ph) chromosome, NCI risk status, ploidy, or an abnormal 9p. However, the impact on survival was not maintained for monosomy 7 after adjustment for a Ph. These results indicate that the critical region of loss of chromosome 7 in pediatric ALL may be on the p-arm.

Dexamethasone versus prednisone and daily oral versus weekly intravenous mercaptopurine for patients with standard-risk acute lymphoblastic leukemia: a report from the Children's Cancer Group

Conventional therapy for childhood acute lymphoblastic leukemia (ALL) includes prednisone and oral 6-mercaptopurine. Prior observations suggested potential advantages for dexamethasone over prednisone and for intravenous (IV) over oral 6-mercaptopurine, which remain to be validated. We report the results of a randomized trial of more than 1000 subjects that examined the efficacy of dexamethasone and IV 6-mercaptopurine. Children with National Cancer Institute standard-risk ALL were randomly assigned in a 2 x 2 factorial design to receive dexamethasone (6 mg/m(2)/d) for 28 days in induction, plus taper, compared with prednisone (40 mg/m(2)/d). The second randomized assignment was for daily oral or weekly IV 6-mercaptopurine during consolidation. During maintenance, 5 days of the randomized steroid was given monthly, at the same dose, and all patients received daily oral 6-mercaptopurine. During delayed intensification, all patients received a dexamethasone dosage of 10 mg/m(2)/d for 21 days, with taper. Intrathecal (IT) methotrexate was the sole central nervous system-directed therapy. Patients randomly assigned to receive dexamethasone had a 6-year isolated central nervous system-relapse rate of 3.7% +/- 0.8%, compared with 7.1% +/- 1.1% for prednisone (P =.01). There was also a trend toward fewer isolated bone marrow relapses with dexamethasone. The 6-year event-free survival (EFS) was 85% +/- 2% for dexamethasone and 77% +/- 2% for prednisone (P =.002). EFS was similar with oral or IV 6-mercaptopurine; however, patients assigned to IV 6-mercaptopurine had decreased survival after relapse.

Expression of HOX11 in childhood T-lineage acute lymphoblastic leukaemia can occur in the absence of cytogenetic aberration at 10q24: a study from the Children's Cancer Group (CCG)

Clonal genetic aberrations in tumour cells provide critical information for the development of new diagnostic and therapeutic strategies for patients. In paediatric T-cell acute lymphoblastic leukaemia (T-ALL) chromosomal translocations are present in 30-35% of cases. HOX11 and the closely related HOX11L2 genes play a key role in T-ALL. HOX11 is aberrantly activated by either of the two chromosomal translocations, t(7;10) and t(10;14). In this study, HOX11 expression levels were measured by real-time quantitative reverse-transcriptase polymerase chain reaction. We show that leukaemic blasts from 15/76 (19.7%) paediatric T-ALL patients expressed the HOX11 gene at high level and 22/76 (28.9%) at low level, yet the reported frequency for chromosomal rearrangement of 10q24 is 4-7%. Direct cytogenetic analysis revealed that only 2/16 specimens that showed HOX11 expression exhibited abnor-malities at 10q24. These results confirm and extend our previously published findings, and implicate mechanisms other than gross chromosomal translocations for the deregulation of HOX11. Analysis of clinical outcome for the whole study group showed a trend for better outcome for patients with leukaemic blasts expressing HOX11 at high level. A statistically significant difference in clinical outcome was found in a subgroup of 20 patients treated for high-risk disease on CCG-1901 from the Children's Cancer Group, where HOX11 expression in leukaemic blasts conferred a prognostic advantage (P=0.01).