Kirk R. Schultz

Improved Early Event-Free Survival With Imatinib in Philadelphia Chromosome–Positive Acute Lymphoblastic Leukemia: A Children's Oncology Group Study

PURPOSE Imatinib mesylate is a targeted agent that may be used against Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL), one of the highest risk pediatric ALL groups. PATIENTS AND METHODS We evaluated whether imatinib (340 mg/m(2)/d) with an intensive chemotherapy regimen improved outcome in children ages 1 to 21 years with Ph+ ALL (N = 92) and compared toxicities to Ph- ALL patients (N = 65) given the same chemotherapy without imatinib. Exposure to imatinib was increased progressively in five patient cohorts that received imatinib from 42 (cohort 1; n = 7) to 280 continuous days (cohort 5; n = 50) before maintenance therapy. Patients with human leukocyte antigen (HLA) -identical sibling donors underwent blood and marrow transplantation (BMT) with imatinib given for 6 months following BMT. RESULTS Continuous imatinib exposure improved outcome in cohort 5 patients with a 3-year event-free survival (EFS) of 80% +/- 11% (95% CI, 64% to 90%), more than twice historical controls (35% +/- 4%; P < .0001). Three-year EFS was similar for patients in cohort 5 treated with chemotherapy plus imatinib (88% +/- 11%; 95% CI, 66% to 96%) or sibling donor BMT (57% +/- 22%; 95% CI, 30.4% to 76.1%). There were no significant toxicities associated with adding imatinib to intensive chemotherapy. The higher imatinib dosing in cohort 5 appears to improve survival by having an impact on the outcome of children with a higher burden of minimal residual disease after induction. CONCLUSION Imatinib plus intensive chemotherapy improved 3-year EFS in children and adolescents with Ph+ ALL, with no appreciable increase in toxicity. BMT plus imatinib offered no advantage over BMT alone. Additional follow-up is required to determine the impact of this treatment on long-term EFS and determine whether chemotherapy plus imatinib can replace BMT.

Hematopoietic Stem-Cell Transplantation for Acute Leukemia in Relapse or Primary Induction Failure

PURPOSE Patients with acute leukemia refractory to induction or reinduction chemotherapy have poor prognoses if they do not undergo hematopoietic stem-cell transplantation (HSCT). However, HSCT when a patient is not in complete remission (CR) is of uncertain benefit. We hypothesized that pretransplantation variables may define subgroups that have a better prognosis. PATIENTS AND METHODS Overall, 2,255 patients who underwent transplantation for acute leukemia in relapse or with primary induction failure after myeloablative conditioning regimen between 1995 and 2004 were reported to the Center for International Blood and Marrow Transplant Research. The median follow-up of survivors was 61 months. We performed multivariate analysis of pretransplantation variables and developed a predictive scoring system for survival. RESULTS The 3-year overall survival (OS) rates were 19% for acute myeloid leukemia (AML) and 16% for acute lymphoblastic leukemia (ALL). For AML, five adverse pretransplantation variables significantly influenced survival: first CR duration less than 6 months, circulating blasts, donor other than HLA-identical sibling, Karnofsky or Lansky score less than 90, and poor-risk cytogenetics. For ALL, survival was worse with the following: first refractory or second or greater relapse, > or = 25% marrow blasts, cytomegalovirus-seropositive donor, and age of 10 years or older. Patients with AML who had a predictive score of 0 had 42% OS at 3 years, whereas OS was 6% for a score > or = 3. Patients with ALL who had a score of 0 or 1 had 46% 3-year OS but only 10% OS rate for a score > or = 3. CONCLUSION Pretransplantation variables delineate subgroups with different outcomes. HSCT during relapse can achieve long-term survival in selected patients with acute leukemia.

A phase II study of imatinib mesylate in children with refractory or relapsed solid tumors: A Children's Oncology Group study†

Imatinib mesylate is a small molecule inhibitor of certain tyrosine kinases, most notably the chimeric bcr‐abl fusion protein found in CML. It also inhibits KIT and PDGF receptor tyrosine kinases in vitro. Ewing sarcoma, osteosarcoma, neuroblastoma, desmoplastic small round cell, and synovial sarcomas often overexpress KIT or the PDGF receptor. A phase II study of imatinib in children and young adults with select solid tumors was performed.

Long-term follow-up of imatinib in pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia: Children's Oncology Group Study AALL0031

We previously reported preliminary findings that post induction imatinib mesylate (340 mg/m2/day), in combination with intensive chemotherapy, resulted in outcomes similar to blood and marrow transplant (BMT) for pediatric patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL). We now report 5-year outcomes of imatinib plus intensive chemotherapy in 91 children (1–21 years) with and without allogeneic BMT (N=91). We explore the impacts of additional chromosomal abnormalities and minimal residual disease (MRD) by flow cytometry on outcomes. The 5-year disease-free survival was similar for Cohort 5 patients, treated with chemotherapy plus imatinib (70%±12%, n=28), sibling donor BMT patients (65%±11%, n=21) and unrelated donor BMT patients (59±15%; P=0.60, n=13). Patients with additional cytogenetic abnormalities had worse outcomes (P=0.05). End induction (pre-imatinib) MRD was not prognostic for Cohort 5 or allogeneic BMT patients, although limited by small numbers. The re-induction rate following relapse was similar to other higher-risk ALL groups. Longer-term follow-up confirms our initial observation of substantially good outcomes for children and adolescents with Ph+ ALL treated with imatinib plus intensive chemotherapy with no advantage for allogeneic BMT.

One-Unit versus Two-Unit Cord-Blood Transplantation for Hematologic Cancers

BACKGROUND Umbilical-cord blood has been used as the source of hematopoietic stem cells in an estimated 30,000 transplants. The limited number of hematopoietic cells in a single cord-blood unit prevents its use in recipients with larger body mass and results in delayed hematopoietic recovery and higher mortality. Therefore, we hypothesized that the greater numbers of hematopoietic cells in two units of cord blood would be associated with improved outcomes after transplantation. METHODS Between December 1, 2006, and February 24, 2012, a total of 224 patients 1 to 21 years of age with hematologic cancer were randomly assigned to undergo double-unit (111 patients) or single-unit (113 patients) cord-blood transplantation after a uniform myeloablative conditioning regimen and immunoprophylaxis for graft-versus-host disease (GVHD). The primary end point was 1-year overall survival. RESULTS Treatment groups were matched for age, sex, self-reported race (white vs. nonwhite), performance status, degree of donor-recipient HLA matching, and disease type and status at transplantation. The 1-year overall survival rate was 65% (95% confidence interval [CI], 56 to 74) and 73% (95% CI, 63 to 80) among recipients of double and single cord-blood units, respectively (P=0.17). Similar outcomes in the two groups were also observed with respect to the rates of disease-free survival, neutrophil recovery, transplantation-related death, relapse, infections, immunologic reconstitution, and grade II-IV acute GVHD. However, improved platelet recovery and lower incidences of grade III and IV acute and extensive chronic GVHD were observed among recipients of a single cord-blood unit. CONCLUSIONS We found that among children and adolescents with hematologic cancer, survival rates were similar after single-unit and double-unit cord-blood transplantation; however, a single-unit cord-blood transplant was associated with better platelet recovery and a lower risk of GVHD. (Funded by the National Heart, Lung, and Blood Institute and the National Cancer Institute; ClinicalTrials.gov number, NCT00412360.).

Unrelated Donor Cord Blood Transplantation for Children with Severe Sickle Cell Disease: Results of One Cohort from the Phase II Study from the Blood and Marrow Transplant Clinical Trials Network (BMT CTN)

The Sickle Cell Unrelated Donor Transplant Trial (SCURT trial) of the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) is a phase II study of the toxicity and efficacy of unrelated donor hematopoietic cell transplantation in children with severe sickle cell disease (SCD) using a reduced-intensity conditioning regimen. Here we report the results for the cord blood cohort of this trial. Eight children with severe SCD underwent unrelated donor cord blood transplantation (CBT) following alemtuzumab, fludarabine, and melphalan. Cyclosporine or tacrolimus and mycophenolate mofetil were administered for graft-versus-host disease (GVHD) prophylaxis. Donor/recipient HLA match status was 6 of 6 (n = 1) or 5 of 6 (n = 7), based on low/intermediate-resolution molecular typing at HLA -A, -B, and high-resolution typing at -DRB1. Median recipient age was 13.7 years (range: 7.4-16.2 years), and median weight was 35.0 kg (range: 25.2-90.2 kg). The median pre-cryopreservation total nucleated cell dose was 6.4 × 10(7) /kg (range: 3.1-7.6), and the median postthaw infused CD34 cell dose was 1.5 × 10(5) /kg (range: 0.2-2.3). All patients achieved neutrophil recovery (absolute neutrophil count >500/mm(3)) by day 33 (median: 22 days). Three patients who engrafted had 100% donor cells by day 100, which was sustained, and 5 patients had autologous hematopoietic recovery. Six of 8 patients had a platelet recovery to >50,000/mm(3) by day 100. Two patients developed grade II acute GVHD. Of these, 1 developed extensive chronic GVHD and died of respiratory failure 14 months posttransplantation. With a median follow-up of 1.8 years (range: 1-2.6), 7 patients are alive with a 1-year survival of 100%, and 3 of 8 are alive without graft failure or disease recurrence. Based upon the high incidence of graft rejection after unrelated donor CBT, enrollment onto the cord blood arm of the SCURT trial was suspended. However, because this reduced-intensity regimen has demonstrated a favorable safety profile, this trial remains open to enrollment for unrelated marrow donor transplants. Novel approaches aimed at improving engraftment will be needed before unrelated CBT can be widely adopted for transplanting patients with severe SCD.

Exome Sequencing and the Management of Neurometabolic Disorders

BACKGROUND Whole-exome sequencing has transformed gene discovery and diagnosis in rare diseases. Translation into disease-modifying treatments is challenging, particularly for intellectual developmental disorder. However, the exception is inborn errors of metabolism, since many of these disorders are responsive to therapy that targets pathophysiological features at the molecular or cellular level. METHODS To uncover the genetic basis of potentially treatable inborn errors of metabolism, we combined deep clinical phenotyping (the comprehensive characterization of the discrete components of a patients clinical and biochemical phenotype) with whole-exome sequencing analysis through a semiautomated bioinformatics pipeline in consecutively enrolled patients with intellectual developmental disorder and unexplained metabolic phenotypes. RESULTS We performed whole-exome sequencing on samples obtained from 47 probands. Of these patients, 6 were excluded, including 1 who withdrew from the study. The remaining 41 probands had been born to predominantly nonconsanguineous parents of European descent. In 37 probands, we identified variants in 2 genes newly implicated in disease, 9 candidate genes, 22 known genes with newly identified phenotypes, and 9 genes with expected phenotypes; in most of the genes, the variants were classified as either pathogenic or probably pathogenic. Complex phenotypes of patients in five families were explained by coexisting monogenic conditions. We obtained a diagnosis in 28 of 41 probands (68%) who were evaluated. A test of a targeted intervention was performed in 18 patients (44%). CONCLUSIONS Deep phenotyping and whole-exome sequencing in 41 probands with intellectual developmental disorder and unexplained metabolic abnormalities led to a diagnosis in 68%, the identification of 11 candidate genes newly implicated in neurometabolic disease, and a change in treatment beyond genetic counseling in 44%. (Funded by BC Childrens Hospital Foundation and others.).

Nonpermissive HLA-DPB1 mismatch increases mortality after myeloablative unrelated allogeneic hematopoietic cell transplantation

We examined current outcomes of unrelated donor allogeneic hematopoietic cell transplantation (HCT) to determine the clinical implications of donor-recipient HLA matching. Adult and pediatric patients who had first undergone myeloablative-unrelated bone marrow or peripheral blood HCT for acute myelogenous leukemia, acute lymphoblastic leukemia, chronic myelogenous leukemia, and myelodysplastic syndrome between 1999 and 2011 were included. All had high-resolution typing for HLA-A, -B, -C, and -DRB1. Of the total (n = 8003), cases were 8/8 (n = 5449), 7/8 (n = 2071), or 6/8 (n = 483) matched. HLA mismatch (6-7/8) conferred significantly increased risk for grades II to IV and III to IV acute graft vs host disease (GVHD), chronic GVHD, transplant-related mortality (TRM), and overall mortality compared with HLA-matched cases (8/8). Type (allele/antigen) and locus (HLA-A, -B, -C, and -DRB1) of mismatch were not associated with overall mortality. Among 8/8 matched cases, HLA-DPB1 and -DQB1 mismatch resulted in increased acute GVHD, and HLA-DPB1 mismatch had decreased relapse. Nonpermissive HLA-DPB1 allele mismatch was associated with higher TRM compared with permissive HLA-DPB1 mismatch or HLA-DPB1 match and increased overall mortality compared with permissive HLA-DPB1 mismatch in 8/8 (and 10/10) matched cases. Full matching at HLA-A, -B, -C, and -DRB1 is required for optimal unrelated donor HCT survival, and avoidance of nonpermissive HLA-DPB1 mismatches in otherwise HLA-matched pairs is indicated.

Comparison of outcome following allogeneic bone marrow transplantation with cyclophosphamide-total body irradiation versus busulphan-cyclophosphamide conditioning regimens for acute myelogenous leukaemia in first remission

Summary. We evaluated transplant‐related mortality (TRM), leukaemia relapse, leukaemia‐free survival (LFS) and overall survival (OS) in patients receiving busulphan and cyclophosphamide (BuCy) or cyclophosphamide and total body irradiation (CyTBI) prior to allogeneic bone marrow transplantation (BMT) for acute myelogenous leukaemia (AML) in first remission. Outcomes of 381 human leucocyte antigen (HLA)‐matched sibling transplants using BuCy were compared with 200 transplants using CyTBI performed between 1988 and 1996. The incidence of hepatic veno‐occlusive disease was higher with BuCy (13%) than with CyTBI (6%) (P = 0·009). Risks of acute and chronic GVHD were similar. In multivariate analysis, relapse risk was higher in the BuCy group [relative risk (RR) = 1·72; 95% confidence interval (CI), 1·05–2·81; P = 0·031]. Eleven of 373 evaluable patients in the BuCy group had a central nervous system relapse in contrast to none of 194 evaluable patients in the CyTBI group (P = 0·016). There were no differences in TRM, LFS and OS. CyTBI conditioning may lower relapse risk but produces comparable TRM, LFS and OS to BuCy for HLA‐matched sibling transplantation in first remission AML.

Increasing Incidence of Chronic Graft-versus-Host Disease in Allogeneic Transplantation: A Report from the Center for International Blood and Marrow Transplant Research

Although transplant practices have changed over the last decades, no information is available on trends in incidence and outcome of chronic graft-versus-host disease (cGVHD) over time. This study used the central database of the Center for International Blood and Marrow Transplant Research (CIBMTR) to describe time trends for cGVHD incidence, nonrelapse mortality, and risk factors for cGVHD. The 12-year period was divided into 3 intervals, 1995 to 1999, 2000 to 2003, and 2004 to 2007, and included 26,563 patients with acute leukemia, chronic myeloid leukemia, and myelodysplastic syndrome. Multivariate analysis showed an increased incidence of cGVHD in more recent years (odds ratio = 1.19, P < .0001), and this trend was still seen when adjusting for donor type, graft type, or conditioning intensity. In patients with cGVHD, nonrelapse mortality has decreased over time, but at 5 years there were no significant differences among different time periods. Risk factors for cGVHD were in line with previous studies. This is the first comprehensive characterization of the trends in cGVHD incidence and underscores the mounting need for addressing this major late complication of transplantation in future research.